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.
   

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Previous RP Research: 2002-2006   
The Retinitis Pigmentosa 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 Retinitis Pigmentosa, click HERE.
 

Latest Research on
Retinitis Pigmentosa
     
Mol Vis. 2008 Jun 6;14:1081-93.
Identification of novel mutations in X-linked retinitis pigmentosa families and implications for diagnostic testing.
Neidhardt J, Glaus E, Lorenz B, Netzer C, Li Y, Schambeck M, Wittmer M, Feil S, Kirschner-Schwabe R, Rosenberg T, Cremers FP, Bergen AA, Barthelmes D, Baraki H, Schmid F, Tanner G, Fleischhauer J, Orth U, Becker C, Wegscheider E, Nürnberg G, Nürnberg P, Bolz HJ, Gal A, Berger W.
Division of Medical Molecular Genetics and Gene Diagnostics, Institute of Medical Genetics, University of Zurich, Switzerland. neidhardt@medgen.uzh.ch

PURPOSE: The goal of this study was to identify mutations in X-chromosomal genes associated with retinitis pigmentosa (RP) in patients from Germany, The Netherlands, Denmark, and Switzerland. METHODS: In addition to all coding exons of RP2, exons 1 through 15, 9a, ORF15, 15a and 15b of RPGR were screened for mutations. PCR products were amplified from genomic DNA extracted from blood samples and analyzed by direct sequencing. In one family with apparently dominant inheritance of RP, linkage analysis identified an interval on the X chromosome containing RPGR, and mutation screening revealed a pathogenic variant in this gene. Patients of this family were examined clinically and by X-inactivation studies. RESULTS: This study included 141 RP families with possible X-chromosomal inheritance. In total, we identified 46 families with pathogenic sequence alterations in RPGR and RP2, of which 17 mutations have not been described previously. Two of the novel mutations represent the most 3'-terminal pathogenic sequence variants in RPGR and RP2 reported to date. In exon ORF15 of RPGR, we found eight novel and 14 known mutations. All lead to a disruption of open reading frame. Of the families with suggested X-chromosomal inheritance, 35% showed mutations in ORF15. In addition, we found five novel mutations in other exons of RPGR and four in RP2. Deletions in ORF15 of RPGR were identified in three families in which female carriers showed variable manifestation of the phenotype. Furthermore, an ORF15 mutation was found in an RP patient who additionally carries a 6.4 kbp deletion downstream of the coding region of exon ORF15. We did not identify mutations in 39 sporadic male cases from Switzerland. CONCLUSIONS: RPGR mutations were confirmed to be the most frequent cause of RP in families with an X-chromosomal inheritance pattern. We propose a screening strategy to provide molecular diagnostics in these families.

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Invest Ophthalmol Vis Sci. 2008 Jun;49(6):2765-72.
The effect of peripheral visual field loss on representations of space: evidence for distortion and adaptation.
Fortenbaugh FC, Hicks JC, Turano KA.
Lions Vision Center, The Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, USA.

PURPOSE: To determine whether peripheral field loss (PFL) systematically distorts spatial representations and to determine whether persons with actual PFL show adaptation effects. METHODS: Nine participants with PFL from retinitis pigmentosa (RP) learned the locations of statues in a virtual environment by walking a predetermined route. After this, the statues were removed and the participants were to walk to where they thought each statue had been located. Placement errors, defined as the differences between the actual and estimated locations, were calculated and decomposed into distance errors and angular offsets. RESULTS: Participants showed distortions in remembered statue locations, with mean placement errors increasing with decreasing field of view (FOV) size. A correlation was found between FOV size and mean distance error but not mean angular offsets. Compared with eye movements of normal-vision participants with simulated PFL from a previous study, the eye movements of the RP participants were shorter in duration, and smaller saccadic amplitudes were observed only for the RP participants with the smallest FOV sizes. The RP participants also made more fixations to the statues than the simulated PFL participants. Results from a real-world replication of the task showed no behavioral differences between simulated and naturally occurring PFL. CONCLUSIONS: PFL is associated with distortions in spatial representations that increase with decreasing FOV. The differences in eye movement and gaze patterns suggest possible adaptive changes on the part of the RP participants. However, the use of different sampling strategies did not aid the performance of the RP participants as FOV size decreased.

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Mol Vis. 2008 May 19;14:922-7.
Mutations in the TOPORS gene cause 1% of autosomal dominant retinitis pigmentosa.
Bowne SJ, Sullivan LS, Gire AI, Birch DG, Hughbanks-Wheaton D, Heckenlively JR, Daiger SP.
The University of Texas Health Science Center, Human Genetics Center, School of Public Health, Houston, TX 77030, USA. sara.j.bowne@uth.tmc.edu

PURPOSE: The purpose of this project was to determine if mutations, including large insertions or deletions, in the recently identified RP31 gene topoisomerase I-binding arginine-serine rich (RS) protein (TOPORS), cause an appreciable fraction of autosomal dominant retinitis pigmentosa (adRP). METHODS: An adRP cohort of 215 families was used to determine the frequency of TOPORS mutations. We looked for mutations in TOPORS by testing 89 probands from the cohort without mutations in other known adRP genes. Mutation detection was performed by fluorescent capillary sequencing and by multiplex ligation probe amplification. RESULTS: Two different TOPORS mutations, p.Glu808X and p.Arg857GlyfsX9, were each identified in one proband. Patients with these mutations exhibited clinical signs typical of advanced adRP. No large deletions or insertions of TOPORS were identified in our study. CONCLUSIONS: Point mutations and small insertions or deletions in TOPORS cause approximately 1% of adRP. Large deletions or insertions of TOPORS are not an appreciable cause of adRP. Contrary to previous reports, no distinct clinical phenotype was seen in these patients.

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Int J Mol Med. 2008 Jun;21(6):715-20.
Evaluation of the common variants of the ABCA4 gene in families with Stargardt disease and autosomal recessive retinitis pigmentosa.
Shastry BS.
Department of Biological Sciences, Oakland University, Rochester, MI 48309, USA. shastry@oakland.edu.

Stargardt disease (STGD) is one of the most common autosomal recessive retinal dystrophies with an estimated incidence of one in 10,000. It affects the central retina (macula). Retinitis pigmentosa (RP) comprises a large and exceptionally heterogeneous group of hereditary disorders of the retina. It is caused by the loss of photoreceptors. The condition is a degenerative disorder characterized by retinal pigment deposits and has an estimated incidence of one in 4,000. Although, to date, 45 known loci have been identified, none of them independently account for a substantial portion of RP. Recently, the photoreceptor cell-specific ATP-binding cassette transporter (ABCA4) gene was found to be mutated in patients with STGD as well as autosomal recessive RP. In order to further understand the contribution of this gene to the susceptibility to STGD and RP, we analyzed three unrelated STGD families and one autosomal recessive RP family specifically for the more common variants (A1038V, G1961E, 2588G-->C, R943Q or 2828G-->A) in the ABCA4 gene. Our analyses employing standard techniques such as polymerase chain reaction, restriction fragment length polymorphism, and direct DNA sequencing of amplified products were able to identify one common variant (R943Q) in all three STGD families but not in the RP family. All three affected STGD individuals, however, were heterozygous for this variation, and this alteration did not segregate with the disease and was also present in the normal controls. Similar analysis of other common variants revealed no pathogenic mutations in the STGD and RP families. It is likely that the variant identified in this study represents a rare polymorphism (non-pathogenic). Although, at present we cannot eliminate the possibility of this gene as a candidate gene, future extensive studies on this as well as other candidate genes may uncover the susceptibility gene for these recessive forms of the disorders in these families.

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Clin Exp Optom. 2008 Mar;91(2):166-76.
Reported effects of non-traditional treatments and complementary and alternative medicine by retinitis pigmentosa patients.
Kiser AK, Dagnelie G.
Johns Hopkins University, Wilmer Eye Institute, Baltimore MD, USA. abittne1@jhmi.edu

BACKGROUND: Benefits of complementary and alternative medicine (CAM)-related interventions have been demonstrated for patients with chronic, systemic diseases in which stress, anxiety and disability are prevalent. Subjects with retinitis pigmentosa (RP) commonly indicate that they have 'good' and 'bad' vision days, stating that stress causes a decrease in vision and that vision improves when the stress is alleviated. We assessed CAM use by RP patients and its perceived effectiveness. METHODS: We enquired about nine CAM areas: meditation, mind-body therapies, yoga, movement therapies, energy therapies, acupuncture, massage therapy, spirituality/religion and herbal therapies/aromatherapy. Ninety-six RP patients with any level of vision completed an anonymous internet survey. RESULTS: Ninety-five per cent of respondents tried at least one of the nine CAM areas. Seventy-five per cent have used nutritional supplements, including lutein (47 per cent), bilberry (32), vitamin A palmitate (36) and docosahexaenoic acid (23 per cent). Some tried meditation (47) and yoga (31 per cent). Stress and anxiety levels were reported as improved in 93, 92 and 87 per cent of those who used yoga, meditation and mind-body therapies, respectively. Many of those who tried mind-body therapies (40) or acupuncture (50 per cent), used it with a desire to fight RP. Vision was subjectively affected in 65 per cent of acupuncture users and from 20 to 35 per cent of the users of the other CAM areas. Those who indicated that their vision was affected by at least one type of CAM (35 per cent) were statistically significantly more likely to require magnification to read (that is, they had lost more vision and RP had progressed), than those who did not believe vision was impacted (59 versus 84 per cent). CONCLUSIONS: RP patients are using CAM and are experiencing some impact on vision and physical/emotional well-being. Clinicians and researchers should be aware of its use. Clinical trials with CAM interventions are necessary to attempt to validate these findings.

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J Ocul Pharmacol Ther. 2008 Jan 17 [Epub ahead of print]
A Pilot Study of Topical Treatment with an alpha(2)-agonist in Patients with Retinal Dystrophies.
Merin S, Obolensky A, Farber MD, Chowers I.
Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel.

Purpose: The aim of this study was to assess the neuroprotective effect of a topical alpha(2)-agonist in patients with retinal dystrophies. Methods: This study was a prospective, placebo-controlled, double-masked, randomized clinical trial. A total of 26 patients with retinal dystrophies were included. One (1) randomly selected eye was treated with brimonidine tartrate 0.2% twice-daily, while the fellow eye received artificial tears. Disease progression parameters tested at 6-8-month intervals throughout the study included Goldmann visual fields, contrast sensitivity, color vision, and fullfield electroretinography. Results: Seventeen (17) of the 26 recruited patients completed the study. Except for 1 patient with an 18-month follow-up, all patients were followed up for 24-36 months (mean, 29). At the conclusion of the study, there were no differences detected in visual acuity, color vision, and contrast sensitivity between the treated and control eyes. There was a trend, however, toward a lesser degree of visual field loss in the brimonidine-treated eyes. There was also a delay in the time required to reach a 25% visual field loss in the treated eyes. These differences were more pronounced in a subgroup of patients diagnosed as retinitis pigmentosa and with visual fields of 5 cm(2) or more at baseline. Conclusions: The findings of this pilot study suggest a trend for slower progression in the eyes of patients with retinal dystrophy when treated with brimonidine, according to one of the parameters that was studied (visual field loss). Further studies that include a larger number of patients and a longer follow-up period are needed to clarify and confirm the potential neuroprotective effect of alpha(2)-agonists in human retinal dystrophies.

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Clin Exp Optom. 2008 Jan;91(1):78-84.
A review of the potential to restore vision with stem cells.
Mooney I, Lamotte J.
Southern California College of Optometry, Fullerton, California, USA.

Vision research involving stem cells is a rapidly evolving field. Animal experiments have shown that in response to environmental cues, stem cells can repopulate damaged retinas, regrow neuronal axons, repair higher cortical pathways, and restore pupil reflexes, light responses and basic pattern recognition. Viable corneas have been grown from stem cells and transplanted into humans. Similarly, human trials to repair damaged retinas in retinitis pigmentosa and age-related macular degeneration patients have produced preliminary successes. This review attempts to place the collective contributions toward stem cell/vision research into a broader clinical model of how stem cells might ultimately be used to restore the entire visual pathway.

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J Biomater Sci Polym Ed. 2007;18(8):1031-55.
Retinal prostheses: current challenges and future outlook.
Winter JO, Cogan SF, Rizzo JF 3rd.
Center for Innovative Visual Rehabilitation, VA Medical Center, Boston, MA, USA. winter.63@osu.edu

Blindness from retinal diseases, including age-related macular degeneration (AMD) and retinitis pigmentosa (RP), usually causes a significant decline in quality of life for affected patients. Currently there is no cure for these conditions. However, over the last decade, several groups have been developing retinal prostheses which hopefully will provide some degree of improved visual function to these patients. Several such devices are now in clinical trials. Unfortunately, the possibility of electrode or tissue damage limits excitation schemes to those that may be employed with electrodes that have relatively low charge densities. Further, the excitation thresholds that have been required to achieve vision to date, in general, are relatively high. This may result in part from poor apposition between neurons and the stimulating electrodes and is confounded by the effects of the photoreceptor loss, which initiates other pathology in the surviving retinal tissue. The combination of these and other factors imposes a restriction on the pixel density that can be used for devices that actively deliver electrical stimulation to the retina. The resultant use of devices with relatively low pixel densities presumably will limit the degree of visual resolution that can be obtained with these devices. Further increases in pixel density, and therefore increased visual acuity, will necessitate either improved electrode-tissue biocompatibility or lower stimulation thresholds. To meet this challenge, innovations in materials and devices have been proposed. Here, we review the types of retinal prostheses investigated, the extent of their current biocompatibility and future improvements designed to surmount these limitations.

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Acta Neurochir Suppl. 2007;97(Pt 2):487-93.
Towards the bionic eye--the retina implant: surgical, opthalmological and histopathological perspectives.
Alteheld N, Roessler G, Walter P.
Department of Ophthalmology, RWTH Aachen University, Aachen, Germany. nalteheld@ukaachen.de

Degenerations of the outer retina such as retinitis pigmentosa (RP) lead to blindness due to photoreceptor loss. There is a secondary loss of inner retinal cells but significant numbers of bipolar and ganglion cells remain intact for many years. Currently, no therapeutic option to restore vision in these blind subjects is available. Short-term pattern electrical stimulation of the retina using implanted electrode arrays in subjects blind from RP showed that ambulatory vision and limited character recognition are possible. To produce artificial vision by electrical retinal stimulation, a wireless intraocular visual prosthesis was developed. Images of the environment, taken by a camera are pre-processed by an external visual encoder. The stimulus patterns are transmitted to the implanted device wirelessly and electrical impulses are released by microcontact electrodes onto the retinal surface. Towards a human application, the biocompatibility of the utilised materials and the feasibility of the surgical implantation procedure were stated. In acute stimulation tests, thresholds were determined and proved to be within a safe range. The local and retinotopic activation of the visual cortex measured by optical imaging of intrinsic signals was demonstrated upon electrical retinal stimulation with a completely wireless and remotely controlled retinal implant. Potential obstacles are reviewed and further steps towards a successful prosthesis development are discussed.

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Acta Neurochir Suppl. 2007;97(Pt 2):481-6.
A neuroprosthesis for restoring sight.
Viola MV, Patrinos AA.
Office of Biological and Environmental Sciences, United States Department of Energy, Germantown, MD, USA.

Macular degeneration (MD) and retinitis pigmentosa (RP), two diseases that cause degeneration of retinal photoreceptor cells, are the leading causes of blindness in the United States. Anatomical studies have shown that other retinal neuronal cells (bipolar cells, ganglion cells) are preserved in these diseases and they are capable of eliciting visual percepts when electrically stimulated. We describe the design of a prototype 16-electrode retinal prosthesis, and the physiological and clinical results on six blind patients with RP who had the device implanted. The US Department of Energy artificial retina program is described. The goal of the program is construction of a 1000-electrode retinal neuroprosthesis with the potential of enabling blind patients to read large print and ambulate with ease.

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Acta Neurochir Suppl. 2007;97(Pt 2):465-72.
Implantable visual prostheses.
Thanos S, Heiduschka P, Stupp T.
Department of Experimental Ophthalmology, University Eye Hospital and Interdisciplinary Centre of Clinical Research (IZKF), Münster, Germany. solon@uni-muenster.de

Visual impairment and blindness is primarily caused by optic neuropathies like injuries and glaucomas, as well as retinopathies like agerelated macular degeneration (MD), systemic diseases like diabetes, hypertonia and hereditary retinitis pigmentosa (RP). These pathological conditions may affect retinal photoreceptors, or retinal pigment epithelium, or particular subsets of retinal neurons, and in particular retinal ganglion cells (RGCs). The RGCs which connect the retina with the brain are unique cells with extremely long axons bridging the distance from the retina to visual relays within the thalamus and midbrain, being therefore vulnerable to heterogeneous pathological conditions along this pathway. When becoming mature, RGCs loose the ability to divide and to regenerate their accidentally or experimentally injured axons. Consequently, any loss of RGCs is irreversible and results to loss of visual function. The advent of micro- and nanotechnology, and the construction of artificial implants prompted to create visual prostheses which aimed at compensating for the loss of visual function in particular cases. The purpose of the present contribution is to review the considerable engineering expertise that is essential to fabricate current visual prostheses in connection with their functional features and applicability to the animal and human eye. In this chapter, 1) Retinal and cortical implants are introduced, with particular emphasis given to the requirements they have to fulfil in order to replace very complex functions like vision. 2) Advanced work on material research is presented both from the technological and from the biocompatibility aspect as prerequisites of any perspectives for implantation. 3) Ultimately, experimental studies are presented showing the shaping of implants, the procedures of testing their biocompatibility and essential modifications to improve the interfaces between technical devices and the biological environment. The review ends by pointing to future perspectives in the rapidly accelerating process of visual prosthetics and in the increasing hope that restoration of the visual system becomes reality.

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Graefes Arch Clin Exp Ophthalmol. 2007 Aug 3; [Epub ahead of print]
Slowing the degenerative process, long lasting effect of hyperbaric oxygen therapy in retinitis pigmentosa.
Vingolo EM, Rocco M, Grenga P, Salvatore S, Pelaia P.
Inherited Degenerative Retinal Diseases Unit, Department of Ophthalmology, Policlinico Umberto I, University of Rome “La Sapienza”, Rome, Italy.

BACKGROUND: Retinitis pigmentosa (RP) therapy is still an unsolved challenge. Recent reports have underlined that hyperbaric oxygen (HBO) therapy could play a role in slowing the retinal degenerative process. The aim of this study was to assess the efficacy of HBO therapy on visual function in RP patients. METHODS: We performed a single-center, comparative, longitudinal case-controlled randomized clinical trial, which lasted 10 years. We randomly divided RP patients into two groups. Group 1, the control group, consisted of 44 RP patients (21 males and 23 females; mean age 35.5) who took Vitamin A. Group 2, with 44 RP patients (21 males and 23 females; mean age 35,02), underwent HBO therapy. No statistically significant difference was found at the beginning of the study between the two groups. We compared the results concerning visual acuity, Goldmann perimetry, static perimetry Humphrey field analyzer (HFA), and electroretinogram (ERG) obtained in the two groups at 5 and 10 y
ears follow-up. Statistical analysis was performed with Kaplan-Meier life-table with the evaluation of log-rank coefficient. RESULTS: At 5 year follow-up, 87.5% of group 2 patients preserved 80% of the initial visual acuity, while the same result was achieved in only 70.4% of group 1 patients (X(2) = 8.2; p < 0.01); at 10 year follow-up, 63.33% of group 2 patients preserved 80% of the initial visual acuity, while the same percentage of residual visual acuity was maintained in 40% of group 1 patients (X(2) = 3.22; p = 0.05). At 10 year follow-up, Goldmann perimetry (target I4e) did not change in 31.6% of group 2 and in 10.5% of group 1; evaluation of mean defect (MD) with static perimetry HFA showed that 53% of HBO patients had 80% of residual mean sensitivity compared to 23.5% of the control group patients (X(2) = 4.72; p = 0.035). ERG b-wave mean values at the end of the protocol were significantly higher in the HBO treated group (X(2) = 4.53; p = 0.013). CONCLUSION: Our study underlines that HBO therapy can be a safe alternative approach to RP patients, contributing to the stabilization of their visual function concerning visual acuity, visual field, and ERG responses while waiting for a definite cure.

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Exp Eye Res. 2007 Jul;85(1):7-14. Epub 2007 Mar 7.
Long-term visual prognoses in patients with retinitis pigmentosa: The Ludwig von Sallmann lecture.
Berson EL.
Havard Medical School, Massachusetts Eye and Ear Infirmary, 243 Charles Street, Boston, MA 02114, USA.

Retinitis pigmentosa can be followed over almost its entire course with narrow bandpassed, computer averaged cone electroretinograms (ERGs). The long-term rate of decline of these responses can be described by an exponential function. A cone ERG actuarial table based on 1039 patients and 6553 visits is presented to show the estimated number of years for an average patient with a given 30-Hz cone ERG amplitude to decline to 0.05muV (i.e. virtual blindness). The table is based on a projected rate of loss of 10% of remaining cone ERG amplitude per year for those not on treatment and 8.3% per year for those on treatment with vitamin A palmitate 15,000IU/day. The table can be used to provide an estimate of the average long-term visual prognosis from a single visit; more precise estimates for a specific patient require several additional visits over 2- to 3-year intervals. Evidence is presented to support the idea that patients with a projected cone amplitude of 3.5muV or greater at age 40 (about 25% of our patient population with typical retinitis pigmentosa) would be expected, on average, to retain some useful vision for their entire lives without treatment. Knowledge of the amount of remaining cone function in the ERG often reduces patient anxiety and helps patients plan for their future.

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Arch Ophthalmol. 2007 Jun;125(6):759-64.
Treatment of cystoid macular edema in retinitis pigmentosa with intravitreal triamcinolone.
Scorolli L, Morara M, Meduri A, Reggiani LB, Ferreri G, Scalinci SZ, Meduri RA.
Department of Pathophysiological Optics, University of Bologna, Via Zuccardi Merli 1, 40141 Bologna, Italy. luciascorolli@yahoo.it

OBJECTIVE: To evaluate the results of treatment with intravitreal triamcinolone acetonide injection in patients with cystoid macular edema secondary to retinitis pigmentosa. METHODS: This prospective, nonrandomized comparative trial included 20 eyes of 20 patients with cystoid macular edema secondary to retinitis pigmentosa (group A) and 20 eyes of 20 control individuals (group B) with the same characteristics who declined treatment. All treated eyes received an intravitreal injection of 0.1 mL of triamcinolone acetonide (4 mg). The total follow-up was 12 months. The main outcome measures were best-corrected visual acuity, central macular thickness measured by optical coherence tomography, and intraocular pressure. RESULTS: No statistically significant changes were observed in best-corrected visual acuity. Central macular thickness showed statistical differences between the 2 groups. Intraocular pressure showed a statistically significant increase after the first day, at 1 month, and at 3 months in both groups but no significant increase afterward. CONCLUSIONS: Intravitreal triamcinolone administration may be useful for select cases of cystoid macular edema in patients with retinitis pigmentosa but its efficacy seems to be limited over time. Therefore, to obtain a good anatomical result and an improvement of best-corrected visual acuity, further treatment would be necessary after 6 months.

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J Neural Eng. 2007 Jun;4(2):R14-31. Epub 2007 Mar 14.
Prosthetic interfaces with the visual system: biological issues.
Cohen ED.
Division of Physics, Office of Science and Engineering Labs, Center for Devices and Radiological Health, HFZ130, 12725 Twinbrook Pkwy. Rockville, MD 20852, USA.

The design of effective visual prostheses for the blind represents a challenge for biomedical engineers and neuroscientists. Significant progress has been made in the miniaturization and processing power of prosthesis electronics; however development lags in the design and construction of effective machine-brain interfaces with visual system neurons. This review summarizes what has been learned about stimulating neurons in the human and primate retina, lateral geniculate nucleus and visual cortex. Each level of the visual system presents unique challenges for neural interface design. Blind patients with the retinal degenerative disease retinitis pigmentosa (RP) are a common population in clinical trials of visual prostheses. The visual performance abilities of normals and RP patients are compared. To generate pattern vision in blind patients, the visual prosthetic interface must effectively stimulate the retinotopically organized neurons in the central visual field to elicit patterned visual percepts. The development of more biologically compatible methods of stimulating visual system neurons is critical to the development of finer spatial percepts. Prosthesis electrode arrays need to adapt to different optimal stimulus locations, stimulus patterns, and patient disease states.

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Br J Ophthalmol. 2007 Jan 10; [Epub ahead of print]
Continued Use of Dorzolamide for the Treatment of Cystoid Macular Edema in Patients with Retinitis Pigmentosa.
Fishman GA, Apushkin M.
University of Illinois Eye and Ear Infirmary, United States.

AIMS: To determine the value of a topical carbonic anhydrase inhibitor for extended treatment of cystoid macular edema (CME) in patients with retinitis pigmentosa (RP). METHODS: Eight patients with RP and foveal cystic-appearing lesions observed on fundus examination and by optical coherence tomography (OCT) testing were treated with a topical form of carbonic anhydrase inhibitor. RESULTS: Foveal cystic-like spaces were documented by OCT testing in all eight patients prior to treatment. All patients showed a significant reduction in their foveal thickness (FT) and foveal zone thickness (FZT) in at least one eye after using 2% dorzolamide three times a day for 1 or 2 months. Six patients demonstrated an improvement in both eyes. After an additional 6 to 13 months of the same treatment regimen, of six patients who showed a sustained reduction in FT and FZT in at least one eye, four demonstrated this reduction in both eyes. While they still remained on Trusopt, a recurrence (rebound) of CME in both eyes was observed in two patients while one patient showed a sustained improvement in one eye and rebound of CME in the other eye. Out of 8 patients, 3 showed an improvement of their visual acuity by 7 letters or more, in at least one eye, on Snellen acuity charts which was determined as clinically significant. CONCLUSION: Results from our study suggest that RP patients could potentially sustain a beneficial effect from continued treatment with a topical form of carbonic anhydrase inhibitor.

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Br J Ophthalmol. 2007 Jan 10; [Epub ahead of print]
Continued Use of Dorzolamide for the Treatment of Cystoid Macular Edema in Patients with Retinitis Pigmentosa.
Fishman GA, Apushkin M.
University of Illinois Eye and Ear Infirmary, United States.

AIMS: To determine the value of a topical carbonic anhydrase inhibitor for extended treatment of cystoid macular edema (CME) in patients with retinitis pigmentosa (RP). METHODS: Eight patients with RP and foveal cystic-appearing lesions observed on fundus examination and by optical coherence tomography (OCT) testing were treated with a topical form of carbonic anhydrase inhibitor. RESULTS: Foveal cystic-like spaces were documented by OCT testing in all eight patients prior to treatment. All patients showed a significant reduction in their foveal thickness (FT) and foveal zone thickness (FZT) in at least one eye after using 2% dorzolamide three times a day for 1 or 2 months. Six patients demonstrated an improvement in both eyes. After an additional 6 to 13 months of the same treatment regimen, of six patients who showed a sustained reduction in FT and FZT in at least one eye, four demonstrated this reduction in both eyes. While they still remained on Trusopt, a recurrence (rebound) of CME in both eyes was observed in two patients while one patient showed a sustained improvement in one eye and rebound of CME in the other eye. Out of 8 patients, 3 showed an improvement of their visual acuity by 7 letters or more, in at least one eye, on Snellen acuity charts which was determined as clinically significant. CONCLUSION: Results from our study suggest that RP patients could potentially sustain a beneficial effect from continued treatment with a topical form of carbonic anhydrase inhibitor.

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Lancet. 2006 Nov 18;368(9549):1795-809.
Retinitis pigmentosa.
Hartong DT, Berson EL, Dryja TP.
Ocular Molecular Genetics Institute, Harvard Medical School, Massachusetts Eye and Ear Infirmary, 243 Charles Street, Boston, MA 02114, USA.

Hereditary degenerations of the human retina are genetically heterogeneous, with well over 100 genes implicated so far. This Seminar focuses on the subset of diseases called retinitis pigmentosa, in which patients typically lose night vision in adolescence, side vision in young adulthood, and central vision in later life because of progressive loss of rod and cone photoreceptor cells. Measures of retinal function, such as the electroretinogram, show that photoreceptor function is diminished generally many years before symptomic night blindness, visual-field scotomas, or decreased visual acuity arise. More than 45 genes for retinitis pigmentosa have been identified. These genes account for only about 60% of all patients; the remainder have defects in as yet unidentified genes. Findings of controlled trials indicate that nutritional interventions, including vitamin A palmitate and omega-3-rich fish, slow progression of disease in many patients. Imminent treatments for retinitis pigmentosa are greatly anticipated, especially for genetically defined subsets of patients, because of newly identified genes, growing knowledge of affected biochemical pathways, and development of animal models.

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Arq Bras Oftalmol. 2006 Sep-Oct;69(5):687-90.
[Visual rehabilitation in patients with retinitis pigmentosa]
[Article in Portuguese]
de Castro CT, Berezovsky A, de Castro DD, Salomao SR.
Setor de Visao Subnormal, Departamento de Oftalmologia, Universidade Federal de Sao Paulo, Sao Paulo, SP, Brasil. celina@oftalmo.epm.br

PURPOSE: To determine which low-vision aids could be useful to patients with retinitis pigmentosa and also the benefits that the rehabilitation program could provide based on visual acuity and/or daily visual tasks. METHODS: A group of 30 patients with retinitis pigmentosa aged from 7 to 73 years were enrolled in this study. Visual acuity and visual function tests (visual field, full-field electroretinogram) was performed and low-vision aids tested. Information about the use of the remaining vision was obtained. After choosing the best optical or electronic devices and before their prescription, a low-vision training program was carried out. RESULTS: The best corrected visual acuity varied from HM (hand movements) to 20/40 for distance and visual acuity better than 16M to 0.5M for near. 90% of the patients had optical devices prescribed: 13 for near, 9 for distance, 2 electronic devices and 3 filters. Three patients with extremely narrow visual field and very low visual acuity were referred to orientation and mobility. CONCLUSIONS: The low-vision aids were useful for the retinitis pigmentosa patients: telescopes, hand-held magnifiers, stand magnifiers, half-eye base-in prism lenses, electronic devices and illumination control were beneficial to enhance visual acuity and visual efficiency. The prescription of low-vision aids was helpful in daily-life activities and a high level of satisfaction with the implemented visual rehabilitation program was reported.
  
Previous RP Research: 2002-2006   
The Retinitis Pigmentosa 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 Retinitis Pigmentosa, click HERE.
 

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