Important Note: The following information is provided for your education. It should not be relied upon for personal diagnosis or treatment. If you believe that a particular therapy applies to you or someone you care about, be sure to consult a doctor before trying it.
   

On Downloading (Please Read Carefully)   
To download or print the Amblyopia File, point your mouse to "File" in the top bar of your Explorer or Netscape window, and click once. Now click once on either "Save As" (download), or "Print" (print), and follow the appropriate prompts.
  
Previous Amblyopia Research: 2002-2006   
The Amblyopia File also contains summaries of past research that has shown promise and may still be standard practice among many physicians. To download earlier research findings on Amblyopia, click HERE.
 

Latest Research on Amblyopia
  
Arch Ophthalmol. 2008 Jul;126(7):891-5. Comment in: Arch Ophthalmol. 2008 Jul;126(7):990-1.
Sutured protective occluder for severe amblyopia.
Arnold RW, Armitage MD, Limstrom SA.
Pediatric Ophthalmology and Strabismus, Ophthalmic Associates, 542 W Second Ave, Anchorage, AK 99501-2242, USA. eyedoc@alaska.net

OBJECTIVE: To investigate the feasibility, acceptability, efficacy, and cost of a newly developed translucent shield that can be fixed by sutures to the orbital rim for a month of amblyopia therapy. METHODS: In an institutional review board-approved protocol for patients with amblyopia who do not adhere to the use of conventional patching, shield occluders were fashioned from heat-moldable sturdy black or translucent (20/4000) plastic with holes drilled for attachment. Under brief general anesthesia, patients aged 5 to 10 years had a thorough examination before the shield occluder was sewn to the brow and cheek of the nonamblyopic eye with 3-0 monofilament polypropylene sutures. RESULTS: Ten children completed this protocol from December 1999 through January 2002. All tolerated the occluder for 12 to 36 days. The resultant skin scars were acceptable to parents, patients, and investigators. The amblyopic eyes improved from a mean (SD) of 0.77 (0.30) logMAR (Snellen equivalent, 20/119) to 0.45 (0.29) logMAR (Snellen equivalent, 20/57), a change of 0.32 (0.16) logMAR lines. There was no damage to the sound (occluded) eye. CONCLUSION: Sew-on occluder shields are an alternative when adherence to the use of other types of patching (often referred to as compliance with patching) is not satisfactory.

------

J Pediatr Ophthalmol Strabismus. 2008 May-Jun;45(3):174-6.
The use of levodopa in the treatment of bilateral amblyopia secondary to uncorrected high hypermetropia.
Abrams MS.
Excel Eye Center, Orem, UT 84057, USA.

The standard treatment of bilateral amblyopia secondary to uncorrected high bilateral hypermetropia has been spectacles and time. The patient described here failed to show adequate improvement in visual acuity after 18 months of standard treatment. Visual acuity improved dramatically when the patient began taking levodopa, dropped precipitously when the medication was discontinued, and returned quickly to post-treatment levels when levodopa was restarted. Visual acuity remained stable when the medication was slowly tapered and discontinued. This report suggests that dopamine may play a role in the pathophysiology of bilateral amblyopia secondary to uncorrected high bilateral hypermetropia.

------

J Refract Surg. 2008 May;24(5):464-72.
LASIK in children with hyperopic anisometropic amblyopia.
Utine CA, Cakir H, Egemenoglu A, Perente I.
Turkiye Hospital, Istanbul, Turkey. cananutine@gmail.com

PURPOSE: To evaluate the results of LASIK for hyperopia in pediatric eyes with amblyopia resulting from anisometropia. METHODS: Thirty-two children with anisometropic amblyopia in whom conventional therapy was unsuccessful underwent unilateral LASIK between 1999 and 2005. Mean patient age was 10.3 +/- 3.1 years (range: 4 to 15 years), and mean follow-up was 20.1 +/- 15.1 months (range: 12 to 60 months). At the last follow-up examination, spherical equivalent refraction, uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and complications were recorded. RESULTS: Mean preoperative and postoperative manifest spherical equivalent refraction of the treated eyes was 5.17 +/- 1.65 and 1.39 +/- 1.21 diopters (D), respectively (P < .01). Mean UCVA was 0.06 +/- 0.09 (range: 0.01 to 0.5) preoperatively and 0.27 +/- 0.23 (range: 0.05 to 0.8) postoperatively (P < .01). Mean BSCVA was 0.20 +/- 0.17 (range: 0.01 to 0.8) preoperatively and 0.35 +/- 0.25 (range: 0.1 to 1.0) postoperatively (P < .01). Six eyes gained > or = 4 lines of BSCVA, 4 eyes gained 2 to 3 lines, 12 eyes gained 1 line, and 9 eyes were unchanged; only 1 eye lost 1 line of BSCVA due to haze in the flap-stroma interface. None of the patients reported halos or glare. There were no intraoperative or postoperative flap complications. CONCLUSIONS: LASIK seems to be an effective and safe procedure for the management of hyperopic anisometropic amblyopia in select cases. Visual acuity improved in the amblyopic eyes and was associated with decreased anisometropia. The refractive response to hyperopic LASIK in children appears to be similar to that of adults with comparable refractive errors.

------

J Vis. 2008 Apr 23;8(4):22.1-14.
Amblyopic perception of biological motion.
Thompson B, Troje NF, Hansen BC, Hess RF.
McGill Vision Research, Department of Ophthalmology, McGill University, Montreal, Canada. ben.thompson@mcgill.ca

Although a number of low-level visual deficits in amblyopia have been identified, it is still unclear to what extent these deficits extend throughout the visual processing hierarchy. Biological motion perception can be a useful measure of local and global visual processing since the point-light stimuli that are often used to study this ability carry both local motion and global form information. To investigate the integrity of the biological motion processing system in amblyopia, we employed both detection and discrimination tasks with coherent or scrambled point-light walkers either alone or embedded in different types of point-light masks. These manipulations allowed for control over the amount of form and/or motion information available to the observers that could be used for task performance. We found that amblyopic eyes could process both the global form and local motion components of point-light walkers, indicating intact processing for these stimuli. However, amblyopic eyes did show an increased susceptibility to the addition of masking dots suggesting that segregation of signal from noise is deficient in amblyopia.

------

Can J Ophthalmol. 2008 Feb;43(1):100-4.
Treatment of anisometropic amblyopia in older children using macular stimulation with telescopic magnification.
Nazemi F, Markowitz SN, Kraft S.

Background: Brain plasticity exists beyond the critical period in children aged 9-17 years and in adults, and can result in vision restitution following more intense amblyopia treatments. Telescopic magnification provides a clearer image and better visual stimulation and hence promotes brain plasticity. The purpose of this study was to investigate the impact of vision therapy with telescopic magnification on brain plasticity when given after the traditional methods of amblyopia treatment currently in use in older children. Methods: The study was a prospective, nonrandomized, interventional case series of children aged 7-18 years with a confirmed diagnosis of anisometropic amblyopia not amenable to any further medical or surgical treatments. Strabismic and deprivation amblyopia cases were excluded. The patients wore newly prescribed glasses and were instructed to use a telescopic device in conjunction with the glasses for 30 minutes every day while watching, undisturbed, a favourite television show. Compliance was verified by the parents and investigated at each visit. The outcome measure selected for this study was best corrected visual acuity (BCVA) achieved at the 6-month follow-up visit. Results: Eighteen study subjects (11 males and 7 females) were recruited aged 7-16 (mean 11.7) years. Before telescopic training sessions the mean BCVA in the amblyopic eye for the entire group was 0.5 (SD 0.3) logMAR units (20/63 equivalent), and this improved following the sessions to 0.24 (SD 0.34) logMAR units (20/35 equivalent) (p < 0.0001). A BCVA of 20/25 or better was achieved in the amblyopic eye in 10 (55.6%) of our 18 study subjects and a BCVA of 20/40 or better in 15 (83.3%) of the 18. There were no side effects evident from the intervention, specifically, no diplopia. Compliance with training was complete as per protocol. Interpretation: The addition of vision rehabilitation therapy in the form of training sessions with telescopic magnification a
s described in this paper enhanced vision restitution in older children with anisometropic amblyopia.

-----

Am J Ophthalmol. 2008 Jan 18 [Epub ahead of print]
Comparative Efficacy of Penalization Methods in Moderate to Mild Amblyopia.
Tejedor J, Ogallar C.
Department of Ophthalmology, Hospital Ramón y Cajal, Madrid, Spain.

PURPOSE: To compare the efficacy and sensory outcome of pharmacologic and optical penalization in the treatment of moderate to mild amblyopia. DESIGN: Randomized clinical trial. METHODS: In an institutional setting, two- to 10-year-old children with strabismic or anisometropic amblyopia (visual acuity in the amblyopic eye at least 20/60) who were cooperative to measure visual acuity using the logarithm of the minimum angle of resolution (logMAR) crowded Glasgow acuity cards were randomized into two groups of therapy (n = 35 in each group), 1% atropine, and optical penalization with positive lenses, after stratification by cause of amblyopia. Visual acuity was tested by the logMAR crowded Glasgow acuity cards, after retinoscopic refraction, and deviation angle were measured by the simultaneous prism and cover or Krimsky test. Stereoacuity was determined using the Titmus fly test and Randot preschool or Randot circles stereoacuity test. Change in visual acuity of the amblyopic
eye and in interocular difference of visual acuity after six months of amblyopia therapy was the main outcome measure; stereoacuity at six months of therapy was a secondary outcome measure. RESULTS: Thirty-one and 32 children completed the outcome examination in the atropine and optical penalization group, respectively. Average improvement in visual acuity of the amblyopic eye was larger in the atropine than in the optical penalization group (3.4 and 1.8 logMAR lines, respectively), as well as average improvement in interocular difference of visual acuity (2.8 and 1.3 logMAR lines, respectively). Better stereoacuity, but nonsignificantly different, was detected in the atropine group. CONCLUSIONS: Atropine penalization may be considered more effective than optical penalization with positive lenses.

-----

Ophthalmology. 2007 Dec;114(12):2293-301.
Optical treatment of amblyopia in astigmatic children: the sensitive period for successful treatment.
Harvey EM, Dobson V, Clifford-Donaldson CE, Miller JM.
Department of Ophthalmology and Vision Science, University of Arizona, Tucson, Arizona 85711, USA. emharvey@u.arizona.edu

OBJECTIVE: To compare the effectiveness of eyeglass treatment of astigmatism-related amblyopia in children younger than 8 years (range, 4.75-7.99 years) versus children 8 years of age and older (range, 8.00-13.53 years) over short (6-week) and long (1-year) treatment intervals. DESIGN: Prospective, interventional, comparative case-control study. PARTICIPANTS: Four hundred forty-six nonastigmatic (right and left eye, <0.75 diopters [D]) and 310 astigmatic (RE, > or =1.00 D) Native American (Tohono O'odham) children in kindergarten or grades 1 through 6. INTERVENTION: Eyeglass correction of refractive error, prescribed for full-time wear, in astigmatic children. MAIN OUTCOME MEASURES: Amount of change in mean right-eye best-corrected letter visual acuity for treated astigmatic children versus untreated, age-matched nonastigmatic children after short (6-week) and long (1-year) treatment intervals. RESULTS: Astigmatic children had significantly reduced mean best-corrected visual acuity at baseline compared to nonastigmatic children. Astigmats showed significantly greater improvement in mean best-corrected visual acuity (0.08 logarithm of the minimum angle of resolution [logMAR] unit; approximately 1 line), than the nonastigmatic children (0.01 logMAR unit) over the 6-week treatment interval. No additional treatment effect was observed between 6 weeks and 1 year. Treatment effectiveness was not dependent on age group (<8 years vs. > or =8 years) and was not influenced by previous eyeglass treatment. Despite significant improvement, mean best-corrected visual acuity in astigmatic children remained significantly poorer than in nonastigmatic children after 1 year of eyeglass treatment, even when analyses were limited to results from highly compliant children. CONCLUSIONS: Sustained eyeglass correction results in significant improvement in best-corrected visual acuity in astigmatic children, including those previously believed to be beyond the sensitive
period for successful treatment.

-----

J Cataract Refract Surg. 2007 Dec;33(12):2028-34.
Laser-assisted subepithelial keratectomy for anisometropic amblyopia in children: outcomes at 1 year.
Astle WF, Rahmat J, Ingram AD, Huang PT.
Vision Clinic, Alberta Children's Hospital, University of Calgary, Calgary, Alberta, Canada. william.astle@calgaryhealthregion.ca

PURPOSE: To assess the refractive, visual acuity, and binocular results of laser-assisted subepithelial keratectomy (LASEK) for anisomyopia, anisohyperopia, and anisoastigmatia in children with various levels of amblyopia secondary to the anisometropic causes. SETTING: Nonhospital surgical facility with follow-up in a hospital clinic setting. METHODS: This retrospective review was of 53 children with anisometropia who had LASEK to correct the refractive difference between eyes. All LASEK procedures were performed using general anesthesia. Patients were divided into 3 groups according to their anisometropia as follows: myopic difference greater than 3.00 diopters (D), astigmatic difference greater than 1.50 D, and hyperopic difference greater than 3.50 D. The children were followed for at least 1 year, and their refractive status, visual acuity, and binocular vision were assessed and recorded at 2 and 6 months as well as 1 year. RESULTS: The mean age at treatment was 8.4 years (range 10 months to 16 years). The mean preoperative anisometropic difference was 6.98 D in the entire group, 9.48 D in the anisomyopic group, 3.13 D in the anisoastigmatic group, and 5.50 D in the anisohyperopic group. One year after LASEK, the mean anisometropic difference decreased to 1.81 D, 2.43 D, 0.74 D, and 2.33 D, respectively, and 54% of all eyes were within +/-1.00 D of the fellow eye, 68% were within +/-2.00 D, and 80% were within +/-3.00 D. Preoperative visual acuity and binocular vision could be measured in 33 children. Postoperatively, 63.6% of children had an improvement in best corrected visual acuity (BCVA) and the remainder had no noted change. No patient had a reduction in BCVA or a loss in fusional ability after LASEK. Of the 33 children, 39.4% had positive stereopsis preoperatively and 87.9% had positive stereopsis 1 year after LASEK. CONCLUSION: Laser-assisted subepithelial keratectomy is an effective surgical alternative to improve visual acuity in a nisometropic children unable to tolerate conventional methods of treatment or in whom these methods fail.

-----

Eye. 2007 Oct 12; [Epub ahead of print]
Assessment of a computer-based treatment for older amblyopes: the Glasgow Pilot Study.
Cleary M, Moody AD, Buchanan A, Stewart H, Dutton GN.
1Orthoptic Department, Gartnavel General Hospital, Glasgow, Scotland.

PurposeThere have been few viable alternatives to patching the better eye as a treatment of amblyopia for more than two centuries. The success of patching depends on compliance, which is problematic for up to 59% of children and their families.MethodsThis pilot study trialled the interactive binocular treatment (I-BiT) system as an alternative amblyopia treatment in 12 older amblyopes (6.1-11.4 years, median 8.2), who had not complied with or responded to occlusion. Virtual reality images were projected to each eye simultaneously via a headset during eight treatment sessions of 25-min duration. Outcome measures were changes in high- (HCVA) and low-contrast log MAR acuity (LCVA) at 1 week, 4 weeks and a final follow-up (3-18 months) after the final treatment.ResultsSustained improvements in HCVA were observed in seven children (58%) and in LCVA in eight children (67%), including two for whom amblyopia was eliminated. Five children had visual acuities equivalent to 6/12 or better at least 6 months after stopping treatment, compared with one child prior to treatment. Significant improvements in HCVA occurred up to the fourth treatment; in LCVA to the seventh treatment.ConclusionSustained improvements in visual acuity were observed for 58% of this small group of children using the I-BiT system, despite prior failure with conventional treatment. This offers hope for a potential time-saving alternative to patching, in which compliance can easily be monitored, but the results need to be validated by means of a randomised controlled trial.

-----

BMJ. 2007 Oct 6;335(7622):707. Epub 2007 Sep 13. Comment in: BMJ. 2007 Oct 6;335(7622):678-9.
Objectively monitored patching regimens for treatment of amblyopia: randomised trial.
Stewart CE, Stephens DA, Fielder AR, Moseley MJ; ROTAS Cooperative.
Department of Optometry and Visual Science, City University, London EC1V 0HB.

OBJECTIVES: To compare visual outcome in response to two prescribed rates of occlusion (six hours a day and 12 hours a day). DESIGN: Unmasked randomised trial. SETTING: Research clinics in two London hospitals. PARTICIPANTS: 97 children with a confirmed diagnosis of amblyopia associated with strabismus, anisometropia, or both. INTERVENTIONS: 18 week period of wearing glasses (refractive adaptation) followed by occlusion prescribed ("patching") for six or 12 hours a day. MAIN OUTCOME MEASURES: Visual acuity measured by logMAR letter recognition; objectively monitored rate of occlusion (hours a day). RESULTS: The mean age of children at study entry was 5.6 (SD 1.5) years. Ninety were eligible for occlusion but 10 dropped out in this phase, leaving 80 children who were randomised to a prescribed dose rate of six (n=40) or 12 (n=40) hours a day. The mean change in visual acuity of the amblyopic eye was not significantly different (P=0.64) between the two groups (0.26 (95% confidence interval 0.21 to 0.31) log units in six hour group; 0.24 (0.19 to 0.29) log units in 12 hour group). The mean dose rates (hours a day) actually received, however, were also not significantly different (4.2 (3.7 to 4.7) in six hour group v 6.2 (5.1 to 7.3) in 12 hour group; P=0.06). The visual outcome was similar for those children who received three to six hours a day or more than six to 12 hours a day, but significantly better than that in children who received less than three hours a day. Children aged under 4 required significantly less occlusion than older children. Visual outcome was not influenced by type of amblyopia. CONCLUSIONS: Substantial (six hours a day) and maximal (12 hours a day) prescribed occlusion results in similar visual outcome. On average, the occlusion dose received in the maximal group was only 50% more than in the substantial group and in both groups was much less than that prescribed. Younger children required the least occlusion.

-----

Am J Ophthalmol. 2007 Oct;144(4):487-96. Epub 2007 Aug 20.
Treatment of bilateral refractive amblyopia in children three to less than 10 years of age.
Wallace DK, Chandler DL, Beck RW, Arnold RW, Bacal DA, Birch EE, Felius J, Frazier M, Holmes JM, Hoover D, Klimek DA, Lorenzana I, Quinn GE, Repka MX, Suh DW, Tamkins S; Pediatric Eye Disease Investigator Group.
Jaeb Center for Health Research, 15310 Amberly Drive, Suite 350, Tampa, FL 33647, USA. pedig@jaeb.org

PURPOSE: To determine the amount and time course of binocular visual acuity improvement during treatment of bilateral refractive amblyopia in children three to less than 10 years of age. DESIGN: Prospective, multicenter, noncomparative intervention. METHODS: One hundred and thirteen children (mean age, 5.1 years) with previously untreated bilateral refractive amblyopia were enrolled at 27 community- and university-based sites and were provided with optimal spectacle correction. Bilateral refractive amblyopia was defined as 20/40 to 20/400 best-corrected binocular visual acuity in the presence of 4.00 diopters (D) or more of hypermetropia by spherical equivalent, 2.00 D or more of astigmatism, or both in each eye. Best-corrected binocular and monocular visual acuities were measured at baseline and at five, 13, 26, and 52 weeks. The primary study outcome was binocular acuity at one year. RESULTS: Mean binocular visual acuity improved from 0.50 logarithm of the minimum angle of resolution (logMAR) units (20/63) at baseline to 0.11 logMAR units (20/25) at one year (mean improvement, 3.9 lines; 95% confidence interval [CI], 3.5 to 4.2). Mean improvement at one year for the 84 children with baseline binocular acuity of 20/40 to 20/80 was 3.4 lines (95% CI, 3.2 to 3.7) and for the 16 children with baseline binocular acuity of 20/100 to 20/320 was 6.3 lines (95% CI, 5.1 to 7.5). The cumulative probability of binocular visual acuity of 20/25 or better was 21% at five weeks, 46% at 13 weeks, 59% at 26 weeks, and 74% at 52 weeks. CONCLUSIONS: Treatment of bilateral refractive amblyopia with spectacle correction improves binocular visual acuity in children three to less than 10 years of age, with most improving to 20/25 or better within one year.

-----

Eur J Ophthalmol. 2007 Sep-Oct;17(5):823-7.
Does compliance with amblyopia management improve following supervised occlusion treatment?
El-Ghrably IA, Longville D, Gnanaraj L.
Department of Ophthalmology, Royal Victoria Infirmary, Newcastle - UK.

PURPOSE. To demonstrate improvement in compliance following supervised occlusion therapy for amblyopia in children who had failed to respond to outpatient treatment. METHODS. Retrospective review of the visual outcome of 30 children who were admitted to an ophthalmology ward for 1-day intensive supervised occlusion. These children had documented poor compliance and previously failed to respond to the outpatient occlusion treatment. During their stay a trained ophthalmology nurse educated parents regarding amblyopia and the benefits of occlusion therapy. Visual acuity (VA) of the amblyopic and fellow eyes was recorded on admission, discharge, and at each subsequent visit. The compliance was recorded from parent's history and also indirectly by noticing improvement in vision. RESULTS. The mean supervised occlusion was 7.4 hours (range 4-12 hours). The compliance with occlusion therapy improved in 23 children (77%) after discharge. The mean duration of occlusion after discharge
improved to 4 hours (range 1-12 hours). The mean follow-up was 18 months (range 4-24 months). Though there was no dramatic improvement in VA at discharge there was a statistically significant improvement in VA between admission and last recorded VA (p<0.0001). Of the 23 children who were compliant with occlusion following discharge, 21 (91%) gained at least one line of acuity in their amblyopic eye on the last assessment of their VA and five of them achieved 6/12. Of the seven children who did not comply with occlusion following discharge, only one patient gained one line improvement in his amblyopic eye. CONCLUSIONS. This study shows that supervised occlusion treatment and parental education was effective in children who had initially failed traditional outpatient treatment.

-----

Graefes Arch Clin Exp Ophthalmol. 2007 Jul 19; [Epub ahead of print]
Effect of oral CDP-choline on visual function in young amblyopic patients.
Fresina M, Dickmann A, Salerni A, De Gregorio F, Campos EC.
Ophthalmology Service, University of Bologna, Bologna, Italy.

PURPOSE: The purpose of the study was to evaluate the effect on visual function of orally administered CDP-choline in addition to patching for the treatment of amblyopia in children. METHODS: This was an open label parallel group study comparing patching plus oral CDP-choline with patching alone. Sixty-one participants (aged between 5 and 10 years) suffering from anisometropic or strabismic amblyopia were divided at random into two groups: Group A, 800 or 1,200 mg (according to the body weight) of orally administered CDP-choline and 2-h patching a day; Group B, 2-h patching a day. Both groups were treated for 30 consecutive days. A follow-up visit was set 60 days after the treatment was discontinued. The main outcome measure was the change in visual acuity of amblyopic eyes as measured by Snellen's E charts. The secondary outcome measures were changes in the visual acuity of amblyopic eye as measured by isolated letters (Snellen's E) and changes in the contrast sensitivity of amblyopic eyes. RESULTS: The addition of CDP-choline to patching therapy was not found to be more effective than patching alone after 30-day treatment. The present results showed that adding CDP-choline to patching stabilised the effects obtained during the treatment period. In fact, whereas the participants treated only with patching showed a decrease in visual acuity at 90 days, these receiving CDP-choline and patching combined appeared to maintain the results obtained (two-way ANOVA: P = 0.0042). Similar results were obtained when measuring visual acuity by isolated Snellen's E letters. CONCLUSIONS: In amblyopic patients, CDP-choline combined with patching contributes to obtaining more stable effects than patching alone.

-----

Clin Exp Optom. 2007 Jul;90(4):250-7.
Amblyopia treatment: an evidence-based approach to maximising treatment outcome.
Webber AL.
School of Optometry and Institute of Health and Biomedical Innovation, Queensland University of Technology, Australia.

The basis of treatment for amblyopia (poor vision due to abnormal visual experience early in life) for 250 years has been patching of the unaffected eye for extended times to ensure a period of use of the affected eye. Over the last decade randomised controlled treatment trials have provided some evidence on how to tailor amblyopia therapy more precisely to achieve the best visual outcome with the least negative impact on the patient and the family. This review highlights the expansion of knowledge regarding treatment for amblyopia and aims to provide optometrists with a summary of research evidence to enable them to better treat amblyopia. Treatment for amblyopia is effective, as it reduces overall prevalence and severity of visual loss in this population. Correction of refractive error alone significantly improves visual acuity, sometimes to the point where further amblyopia treatment is not required. Atropine penalisation and patch occlusion are effective in treating amblyopia. Lesser amounts of occlusion or penalisation have been found to be just as effective as greater amounts. Recent evidence has highlighted that occlusion or penalisation in amblyopia treatment can create negative changes in behaviour in children and impact on family life. These complications should be considered when prescribing treatment because they can negatively affect compliance. Studies investigating the maximum age at which treatment of amblyopia can still be effective and the importance of near activities during occlusion are ongoing.

-----

Am J Ophthalmol. 2007 Jun;143(6):1060-3.
Treatment of strabismic amblyopia with refractive correction.
Cotter SA, Edwards AR, Arnold RW, Astle WF, Barnhardt CN, Beck RW, Birch EE, Donahue SP, Everett DF, Felius J, Holmes JM, Kraker RT, Melia BM, Repka MX, Wallace DK, Weise KK; Pediatric Eye Disease Investigator Group.

PURPOSE: To report data on the response of previously untreated strabismic amblyopia to spectacle correction. DESIGN: Prospective, interventional case series. METHODS: Twelve patients with previously untreated strabismic amblyopia were prescribed spectacles and examined at five-week intervals until visual acuity was not improved from the prior visit. RESULTS: Amblyopic eye acuity improved by 2 lines or more from spectacle-corrected baseline acuity in nine of the 12 patients (75%), resolving in three (interocular difference </=1 line). Mean change from baseline to maximum improvement was 2.2 +/- 1.8 lines. Improvement continued for up to 25 weeks. CONCLUSIONS: These results support the suggestion from a prior study that strabismic amblyopia can improve and even resolve with spectacle correction alone. Larger studies with concurrent controls are needed to confirm or refute these findings.

-----

J Refract Surg. 2007 May;23(5):447-55.
Improvement of visual acuity following refractive surgery for myopia and myopic anisometropia.
Vuori E, Tervo TM, Holopainen MV, Holopainen JM.
Department of Ophthalmology, University of Helsinki, Helsinki, Finland.

PURPOSE: To test the hypothesis that anisometropic adults without significant amblyopia suffer from mild visual impairment probably due to aniseikonia, which might be improved by corneal refractive surgery. METHODS: Fifty-seven patients presenting with myopic anisometropia > or = 3.25 diopters (D) and 174 myopic controls appropriate for refractive surgery were included. Photorefractive keratectomy (PRK) or LASIK was performed on 57 anisometropic eyes. As 43 of the 174 myopic control patients had bilateral surgery, PRK or LASIK was performed on 217 myopic control eyes. Best spectacle-corrected visual acuity (BSCVA), refraction, and refractive correction were measured preoperatively and at 1, 3, 5 to 7, 8 to 13, and 25 months following surgery. RESULTS: Preoperative mean spherical equivalent was -7.20 +/- 2.40 D for anisometropic patients and -6.40 +/- 1.90 D for myopic patients. At 8 to 13 months postoperatively, when 23 (40%) anisometropic eyes and 94 (43%) myopic eyes were examined, the mean spherical equivalent refractions were -0.80 +/- 1.60 D and -0.30 +/- 0.60 D, respectively. Preoperatively, the mean BSCVA on a logMAR scale was -0.0143 +/- 0.0572 (Snellen 0.98 +/- 0.12) in the anisometropic group and 0.0136 +/- 0.0361 (Snellen 1.04 +/- 0.09) in the control group (P = .001). Eight to 13 months postoperatively, these values were 0.0076 +/- 0.0659 (Snellen 1.03 +/- 0.15) and 0.0495 +/- 0.0692 (Snellen 1.13 +/- 0.18) and this difference remained statistically significant (P = .012). For the myopic patients, the improvement in BSCVA reached almost maximum at 3 months, and this improvement was found to be highly significant 3 months after surgery (P = .001). The improvement in BSCVA was significantly slower for anisometropic patients and became statistically significant only after 8 to 13 months postoperatively (P = .041). CONCLUSIONS: Anisometropia reduces visual acuity in the more myopic eye and can be at least partially reversed by refractive correction. The slower improvement in BSCVA for anisometropic patients suggests plastic changes in the visual cortex following refractive surgery.

-----

Arch Ophthalmol. 2007 May;125(5):655-9.
Stability of visual acuity improvement following discontinuation of amblyopia treatment in children aged 7 to 12 years.
Hertle RW, Scheiman MM, Beck RW, Chandler DL, Bacal DA, Birch E, Chu RH, Holmes JM, Klimek DL, Lee KA, Repka MX, Weakley DR; Pediatric Eye Disease Investigator Group.
Jaeb Center for Health Research, 15310 Amberly Drive, Tampa, FL 33647, USA. pedig@jaeb.org

OBJECTIVE: To assess the stability of visual acuity improvement during the first year after cessation of amblyopia treatment other than spectacle wear in children aged 7 to 12 years. METHODS: At the completion of a multicenter randomized trial during which amblyopia treated with patching and atropine improved by at least 2 lines on the electronic Early Treatment of Diabetic Retinopathy Study testing protocol, 80 patients aged 7 to 12 years were followed up while not receiving treatment (other than spectacle wear) for 1 year. MAIN OUTCOME MEASURE: Ten letters or more (> or =2 lines) worsening of visual acuity (measured using the electronic Early Treatment of Diabetic Retinopathy Study testing protocol) during the year following treatment discontinuation. RESULTS: During the year following cessation of treatment, the cumulative probability of worsening visual acuity (> or =2 lines) was 7% (95% confidence interval, 3%-17%); 82% of patients maintained an increase in visual acuity of 10 letters or more compared with their visual acuity before starting treatment. CONCLUSION: Visual acuity improvement occurring during amblyopia treatment is sustained in most children aged 7 to 12 years for at least 1 year after discontinuing treatment other than spectacle wear. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT00094692.

-----

Ophthalmology. 2007 Apr;114(4):643-7. Epub 2006 Dec 22.
Optical analysis of visual improvement after correction of anisometropic amblyopia with a phakic intraocular lens in adult patients.
Alió JL, Ortiz D, Abdelrahman A, de Luca A.
Department of Refractive Surgery, Instituto Oftalmológico de Alicante, Vissum Corporation, Alicante, Spain. rdioa@vissum.com

PURPOSE: To analyze possible reasons for an increase in visual acuity observed in myopic patients with anisometropic amblyopia after implantation of a phakic intraocular lens (PIOL) using a theoretical eye model. DESIGN: Retrospective case series. PARTICIPANTS: Fifty-nine eyes of 48 patients with anisometropic amblyopia implanted with an angle-supported PIOL. METHODS: Inclusion criteria were anisometropia of at least 3 diopters (D) and a best spectacle-corrected visual acuity (BSCVA) of 0.7 or less in the best eye. Follow-up was performed at 1, 3, 6, and 12 months and then annually for up to 10 years. The theoretical analysis of mechanisms to explain the visual improvement was performed using a theoretical eye, based on the Kooijman model, in which the measured values of radii and thickness of the different surfaces were substituted. The magnification and spot size were calculated by a ray tracing process. MAIN OUTCOME MEASURES: Uncorrected visual acuity, improvement in best spectacle-corrected visual acuity, and spherical equivalent. RESULTS: Mean gain in visual acuity was 3 lines (range, 0-7 lines). Fifty-four eyes (91.5%) gained at least 1 line of visual acuity, whereas no eyes lost lines of vision. The change in BSCVA did not correlate with preoperative BSCVA (Pearson coefficient, r = 0.19) or with the degree of anisometropia (Pearson coefficient, r = 0.23). The calculations using a Kooijman eye model corrected with spectacles and with a PIOL accounted for the full increase in visual acuity in terms of the magnification (increased by a factor of 1.2) and the spot size (reduced by a factor of 2). CONCLUSIONS: After implantation of a PIOL, the visual acuity of myopic patients with anisometropic amblyopia showed a significant increase. This increase was explained using a theoretical eye model not only in terms of magnification but also including changes in aberrations. An evident role of neuroprocessing in this visual improvement was not identified.

-----

Binocul Vis Strabismus Q. 2007;22(1):49-56.
Long term vision outcomes of conventional treatment of strabismic and anisometropic functional amblyopia.
Garoufalis P, Georgievski Z, Koklanis K.

PURPOSE: To investigate the long-term vision outcomes of amblyopia treatment in "successfully" compared with "unsuccessfully" treated patients. METHODS: Forty-two participants (n=42, mean age 14.8 years, range 10-25 years) were enrolled in the study. Individuals with strabismic or mixed (strabismic and anisometropic) amblyopia were examined at a mean of 6.6 years (range 1-18 years) after cessation of amblyopia treatment. Participants were classified as being "successfully" treated (Group 1) if visual acuity of 6/7.5 or better was achieved at cessation of treatment, or "unsuccessfully" treated (Group 2) if visual acuity of 6/9 or less was achieved at cessation of treatment. Visual acuity was analyzed by calculating an interocular score or difference in visual acuity between the amblyopic and non amblyopic normal (control) eye. RESULTS: A deterioration of visual acuity occurred in 62% of the participants in both Groups 1 and 2. The mean deterioration of visual acuity over time for either group was less than one LogMAR chart line and was not "statistically significant" by convention (F [1,39] = 3.361, p=0.074). The outcomes achieved at cessation of treatment did not "statistically significantly" affect the mean deterioration that occurred over time (F [1,49] = 0.031, p=0.860). CONCLUSION: Visual acuity was relatively stable over a mean followup period of 6.6 years. The treatment outcome and the success of amblyopia treatment were found to be irrelevant to long term stability of visual acuity. These findings suggest that amblyopia treatment mostly results in a lasting improvement in visual acuity, and that both unsuccessfully and successfully treated individuals maintain their visual acuity improvement achieved during treatment.

-----

Am Fam Physician. 2007 Feb 1;75(3):361-7.
Amblyopia.
Doshi NR, Rodriguez ML.
Department of Family, Community and Preventive Medicine, Drexel University College of Medicine, Warminster, Pennsylvania 18974, USA.

Amblyopia, a decrease in visual acuity, is a major public health problem with a prevalence of 1 to 4 percent in the United States. It is thought to develop early in life during the critical period of visual development. Early recognition of amblyogenic risk factors such as strabismus, refractive errors, and anatomic obstructions can facilitate early treatment and increase the chance for recovery of visual acuity. Multiple medical organizations endorse screening for visual abnormalities in children and young adults, yet only 20 percent of school-age children have routine vision screening examinations. Any child with a visual acuity in either eye of 20/40 or worse at age three to five years or 20/30 or worse at age six years or older, or a two-line difference in acuity between eyes, should be referred to an ophthalmologist for further evaluation and definitive therapy. Treatment is started at the time of diagnosis and depends on the etiology. Treatment options for children with strabismus include patching and atropine drops. Children with refractive errors should be prescribed corrective lenses. Corneal lesions, cataracts, and ptosis require surgery. The success of therapy is highly dependent on treatment compliance. Patients and their parents should be educated about the need for regular follow-up and the risk of permanent vision loss.

-----

Klin Monatsbl Augenheilkd. 2007 Jan;224(1):40-6.
[Evaluation of Visual Acuity in a Historical Cohort of 137 Patients Treated for Amblyopia by Occlusion 30 - 35 Years ago.]
[Article in German]
Simonsz-Toth B, Loudon SE, van Kempen-du Saar H, van de Graaf ES, Groenewoud JH, Simonsz HJ.
Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Niederlande (Leitung Prof. Dr. J. P. Mackenbach).

BACKGROUND: Opinions differ on the course of the visual acuity in the amblyopic eye after cessation of occlusion therapy. This study evaluated visual acuity in a historical cohort treated for amblyopia with occlusion therapy 30 - 35 years ago. MATERIALS AND METHODS: Between 1968 and 1975, 1250 patients had been treated by the orthoptist in the Waterland Hospital in Purmerend, the Netherlands. Of these, 471 received occlusion treatment for amblyopia (prevalence 5.0 %, after comparison with the local birth rate). We were able to contact 203 of these patients, 137 were orthoptically re-examined in 2003. We correlated the current visual acuity with the cause of amblyopia, the age at start and end of treatment, the visual acuity at start and end of treatment, fixation, binocular vision and refractive errors. RESULTS: Mean age at the start of treatment was 5.4 +/- 1.9 years, 7.4 +/- 1.7 years at the end and 37 +/- 2.7 years at follow-up. Current visual acuity in the amblyopic eye was correlated with a low visual acuity at the start (p < 0.0001) and end (p < 0.0001) of occlusion therapy, an eccentric fixation (p < 0.0001), and the cause of amblyopia (p = 0,005). At the end of the treatment, patients with a strabismic amblyopia (n = 98) had a visual acuity in the amblyopic eye of 0.29 logMAR +/- 0.3, and in 2003 0.27 +/- 0.3 logMAR. In patients with an anisometropic amblyopia (> 1 D, n = 16) visual acuity had decreased from 0.17 +/- 0.23 logMAR to 0.21 logMAR +/- 0.23. In patients with both strabismic and anisometropic amblyopia (n = 23), visual acuity had decreased from 0.52 logMAR +/- 0.54 to 0.65 logMAR +/- 0.54. Overall, acuity had decreased in 54 patients (39 %) after cessation of treatment. Of these, 18 patients had an acuity decrease to less than 50 % of their acuity at the end of treatment. In 15 of these 18 patients anisohypermetropia had increased. CONCLUSIONS: A decrease in visual acuity after cessation of occlusion therapy occurred in patients with a combined cause of amblyopia or with an increase in anisohypermetropia.

-----

Indian J Ophthalmol. 2006 Dec;54(4):257-60.
Efficiency of occlusion therapy for management of amblyopia in older children.
Brar GS, Bandyopadhyay S, Kaushik S, Raj S.
Department of Ophthalmology, Postgraduate Institute of Medical Education and Research, Chandigarh, Punjab, India. eyepgi@sify.com

PURPOSE: To analyse results of full time occlusion therapy for amblyopia in children older than 6 years. MATERIALS AND METHODS: This was a retrospective consecutive case series analysis of children treated for amblyopia at a tertiary care center. All children received full time occlusion (FTO) for the dominant eye. RESULTS: Eighty-eight children older than 6 years at the time of initiation of therapy were included. Age at initiation of therapy ranged from 6 to 20 years (9.45 +/- 3.11 years). Forty-two children (47.7%) had strabismic amblyopia, 37 (42.0%) had anisometropic amblyopia and 9 (10.2%) had a combination of strabismic and anisometropic amblyopia. Eighty out of 88 eyes (90.0%) had improvement in visual acuity following FTO. Visual acuity (VA) improved from 0.82 +/- 0.34 at presentation to 0.42 +/- 0.34 (P < 0.001) after FTO. In children with strabismic amblyopia, VA improved from 0.81 +/- 0.42 to 0.42 +/- 0.39 (P <0.001). In children with anisometropic amblyopia, visual acuity of the amblyopic eye improved fron 0.82 +/- 0.24 to 0.36 +/- 0.29 (P< 0.001) following FTO. Out of 13 children older than 12 years, only 6 children (46.1%) had improvement in VA. Mean follow-up after complete stoppage of occlusion was 8.37 +/- 1.78 months. CONCLUSION: Occlusion therapy yields favorable results in strabismic and/or anisometropic amblyopia, even when initiated for the first time after 6 years of age. After 12 years of age, some children may still respond to occlusion of the dominant eye.

-----

Ophthalmology. 2006 Dec 21; [Epub ahead of print]
Optical Analysis of Visual Improvement after Correction of Anisometropic Amblyopia with a Phakic Intraocular Lens in Adult Patients.
Alio JL, Ortiz D, Abdelrahman A, Luca AD.
Department of Refractive Surgery, Instituto Oftalmologico de Alicante, Vissum Corporation, Alicante, Spain; Division of Ophthalmology, School of Medicine, Miguel Hernandez University, Alicante, Spain.

PURPOSE: To analyze possible reasons for an increase in visual acuity observed in myopic patients with anisometropic amblyopia after implantation of a phakic intraocular lens (PIOL) using a theoretical eye model. DESIGN: Retrospective case series. PARTICIPANTS: Fifty-nine eyes of 48 patients with anisometropic amblyopia implanted with an angle-supported PIOL. METHODS: Inclusion criteria were anisometropia of at least 3 diopters (D) and a best spectacle-corrected visual acuity (BSCVA) of 0.7 or less in the best eye. Follow-up was performed at 1, 3, 6, and 12 months and then annually for up to 10 years. The theoretical analysis of mechanisms to explain the visual improvement was performed using a theoretical eye, based on the Kooijman model, in which the measured values of radii and thickness of the different surfaces were substituted. The magnification and spot size were calculated by a ray tracing process. MAIN OUTCOME MEASURES: Uncorrected visual acuity, improvement in best spectacle-corrected visual acuity, and spherical equivalent. RESULTS: Mean gain in visual acuity was 3 lines (range, 0-7 lines). Fifty-four eyes (91.5%) gained at least 1 line of visual acuity, whereas no eyes lost lines of vision. The change in BSCVA did not correlate with preoperative BSCVA (Pearson coefficient, r = 0.19) or with the degree of anisometropia (Pearson coefficient, r = 0.23). The calculations using a Kooijman eye model corrected with spectacles and with a PIOL accounted for the full increase in visual acuity in terms of the magnification (increased by a factor of 1.2) and the spot size (reduced by a factor of 2). CONCLUSIONS: After implantation of a PIOL, the visual acuity of myopic patients with anisometropic amblyopia showed a significant increase. This increase was explained using a theoretical eye model not only in terms of magnification but also including changes in aberrations. An evident role of neuroprocessing in this visual improvement was not identified.

-----

Ophthalmology. 2006 Nov;113(11):2097-100.
Recurrence of amblyopia after occlusion therapy.
Bhola R, Keech RV, Kutschke P, Pfeifer W, Scott WE.
Department of Ophthalmology, University of Iowa Hospitals and Clinics, Iowa City, Iowa 52246, USA.

PURPOSE: To determine the stability of visual acuity (VA) after a standardized occlusion regimen in children with strabismic and/or anisometropic amblyopia. DESIGN: Retrospective, population-based, consecutive observational case series. PARTICIPANTS: Four hundred forty-nine patients younger than 10 years who underwent an occlusion trial for amblyopia and were observed until there was a recurrence of amblyopia or for a maximum of 1 year after decrease or cessation of occlusion therapy. METHODS: We performed a retrospective chart review of all patients treated by occlusion therapy for strabismic and/or anisometropic amblyopia at our institution over a 34-year period. Of the 1621 patients identified in our database, 449 met the eligibility criteria and were included in this study. Patients having at least a 2 logarithm of the minimum angle of resolution (logMAR)-level improvement in VA by optotypes or a change from unmaintained to maintained fixation preference during the course of occlusion therapy were included. A recurrence of amblyopia was defined as > or =2 logMAR levels of VA reduction or reversal of fixation preference within 1 year after a decrease or cessation of occlusion therapy. MAIN OUTCOME MEASURE: Recurrence of amblyopia after a decrease or cessation of occlusion therapy and its relationship with patient age and VA of the amblyopic eye at the time of decrease or cessation of occlusion therapy. RESULTS: Of 653 occlusion trials, 179 (27%) resulted in recurrence of amblyopia. The recurrence was found to be inversely correlated with patient age. There was no statistically significant association between the recurrence of amblyopia and VA of the amblyopic eye at the end of maximal occlusion therapy. CONCLUSIONS: There is a clinically important risk of amblyopia recurrence when occlusion therapy is decreased before the age of 10 years. The risk of recurrence is inversely correlated with age (P<0.0001).

-----

Binocul Vis Strabismus Q. 2006;21(4):231-4.
Refractive eye surgery in treating functional amblyopia in children.
Levenger S, Nemet P, Hirsh A, Kremer I, Nemet A.
Saclker School of Medicine, Tel Aviv University, Kfar Saba, Israel.

PURPOSE: While excimer laser refractive surgery is recommended and highly successful for correcting refractive errors in adults, its use in children has not been extensively exercised or studied. We report our experience treating children with amblyopia due to high anisometropia, high astigmatism, high myopia and with associated developmental delay. SETTING: Review of patient records of our refractive clinic. METHODS: A retrospective review was made of all 11 children with stable refractive errors who were unsuccessfully treated non-surgically and then underwent corneal refractive surgery and in one case, lenticular surgery. Seven had high myopic anisometropia, 2 had high astigmatism, and two had high myopia--one with Down's Syndrome and one with agenesis of the corpus callosum. RESULTS: The surgical refractive treatment eliminated or reduced the anisometropia, reduced the astigmatic error, improved vision and improved the daily function of the children with developmental delay. There were no complications or untoward results. CONCLUSIONS: Refractive surgery is safe and effective in treating children with high myopic anisometropia, high astigmatism, high myopia and developmental delay due to the resulting poor vision. Surgery can improve visual acuity in amblyopia not responding to routine treatment by correcting the refractive error and refractive aberrations.
  
Previous Amblyopia Research: 2002-2006   
The Amblyopia File also contains summaries of past research that has shown promise and may still be standard practice among many physicians. To download earlier research findings on Amblyopia, click HERE.

 

The Amblyopia FileSM Compiled and Maintained by    The Center for Current Research, Inc. 708 Aubrey Avenue • Ardmore PA USA 19003 Phone: 610-649-3165 Email: customerservice@lifestages.com Website: www.centercurrentresearch.com

©Copyright 1992-date by The Center for Current Research. The Amblyopia File is a proprietary compilation of the Center for Current Research. The information in the File is solely for your use, and the use of your family, friends, and doctors. The information is the property of the individual researchers and institutions that produced it. It is an infringement of copyright law to attempt to "resell" the information as it is presented here.