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Felius J.,Retina Foundation of the Southwest | Beauchamp C.L.,Pediatric Ophthalmology and Center for Adult Strabismus | Stager Sr. D.R.,Pediatric Ophthalmology and Center for Adult Strabismus
American Journal of Ophthalmology | Year: 2014

Purpose To investigate the association between visual acuity deficits and fixation instability in children with Down syndrome and nystagmus. Design Prospective cross-sectional study. Methods setting: Institutional. study population:Sixteen children (aged 10 months-14 years) with Down syndrome and nystagmus, and a control group of 93 age-similar children with unassociated infantile nystagmus. observation procedures: Binocular Teller acuity card testing and eye-movement recordings. Fixation stability was quantified using the nystagmus optimal fixation function (NOFF). An exponential model based on results from the control group with unassociated infantile nystagmus was used to relate fixation stability to age-corrected visual acuity deficits. main outcome measures: Binocular grating visual acuity and NOFF. Results Visual acuity was 0.2-0.9 logMAR (20/30-20/174 Snellen equivalent) and corresponded to a 0.4 logMAR (4 lines) mean age-corrected visual acuity deficit. Fixation stability ranged from poor to mildly affected. Although visual acuity deficit was on average 0.17 logMAR larger (P =.005) than predicted by the model, most children had visual acuity deficit within the 95% predictive interval. Conclusions There was a small mean difference between the measured visual acuity deficit and the prediction of the nystagmus model. Although other factors also contribute to visual acuity loss in Down syndrome, nystagmus alone could account for most of the visual acuity deficit in these children. © 2014 BY ELSEVIER INC. ALL RIGHTS RESERVED.


Birch D.G.,Retina Foundation of the Southwest | Weleber R.G.,Oregon Health And Science University | Duncan J.L.,University of California at San Francisco | Jaffe G.J.,Duke University | Tao W.,Neurotech
American Journal of Ophthalmology | Year: 2013

Purpose: To evaluate the safety and effect on visual function of ciliary neurotrophic factor delivered via an intraocular encapsulated cell implant for the treatment of retinitis pigmentosa (RP). Design: Ciliary neurotrophic factor for late-stage retinitis pigmentosa study 3 (CNTF3; n = 65) and ciliary neurotrophic factor for early-stage retinitis pigmentosa study 4 (CNTF4; n = 68) were multicenter, sham-controlled dose-ranging studies. Methods: Patients were randomly assigned to receive a high- or low-dose implant in 1 eye and sham surgery in the fellow eye. The primary endpoints were change in best-corrected visual acuity (BCVA) at 12 months for CNTF3 and change in visual field sensitivity at 12 months for CNTF4. Patients had the choice of retaining or removing the implant at 12 months for CNTF3 and 24 months for CNTF4. Results: There were no serious adverse events related to either the encapsulated cell implant or the surgical procedure. In CNTF3, there was no change in acuity in either ciliary neurotrophic factor- or sham-treated eyes at 1 year. In CNTF4, eyes treated with the high-dose implant showed a significant decrease in sensitivity while no change was seen in sham- and low dose-treated eyes at 12 months. The decrease in sensitivity was reversible upon implant removal. In both studies, ciliary neurotrophic factor treatment resulted in a dose-dependent increase in retinal thickness. Conclusions: Long-term intraocular delivery of ciliary neurotrophic factor is achieved by the encapsulated cell implant. Neither study showed therapeutic benefit in the primary outcome variable. © 2013 Elsevier Inc. All rights reserved.


News Article | February 15, 2017
Site: www.technologyreview.com

The companies, GenSight Biologics of Paris and Bionic Sight, a startup out of Weill Cornell Medical College in New York, both say a combination of wearable electronics and gene therapy has a chance to restore vision by re-creating the retina’s ability to sense light. Both companies are aiming to help patients with a degenerative eye disease called retinitis pigmentosa, which destroys light-sensing cells in the retina. If the approach works, it could in theory be used to treat any type of retinal disease that involves the loss of these cells, called photoreceptors. Optogenetics, a form of gene therapy, offers an unconventional but potentially powerful way to bypass damaged photoreceptors. Using the technique, scientists add genetic instructions to a different type of retinal cells, ganglions, so that they become light-sensitive instead. Working with the Institut de la Vision in Paris, GenSight has developed a pair of goggles containing a camera, a mircroprocessor, and a digital micromirror that will convert images the camera captures into bright pulses of red light in order to stimulate the modified cells. When tested in blind monkeys and rats, the technology appeared to restore their ability to see, says GenSight CEO Bernard Gilly, but only a test in human volunteers who are able to describe what they perceive after being treated will be definitive. He expects a human study to start this year. The companies are also closely tracking results from an initial human test of optogenetics carried out last March in Texas. In a trial being led by RetroSense Therapeutics, recently acquired by Allergan, a blind woman became first person to receive an optogenetic treatment to help restore her vision. That study has so far enrolled four patients, according to David Birch of the Retina Foundation of the Southwest, where the trial is taking place. Each patient gets three injections into the eye of an engineered virus carrying a gene from algae, which instructs cells to make the light-sensitive protein. The team hasn’t yet reported its results, so it’s unknown whether the subjects have gotten any of their vision back. The RetroSense study relies on natural light to activate the cells. That could limit the treatment’s effectiveness, because the light-sensing proteins only respond to specific wavelengths of light, and low levels of ambient or natural light may not be bright enough to trigger them. Richard Masland, an ophthalmology professor at Harvard Medical School and a scientific advisor for RetroSense, says that is why companies are looking into goggles or other “light adaptation machinery” as way to beam light of the right wavelengths and intensity into the eye. Also pursuing a combination of goggles and optogenetics is Bionic Sight, a startup founded by Sheila Nirenberg, a neuroscientist at Weill Cornell Medical College. The company said in January that it would partner with the gene-therapy company Applied Genetic Technologies to begin clinical trials by 2018. It’s still unclear what sort of vision will result from stimulating the ganglion cells, as these cells normally act to relay nerve impulses and don’t receive light directly. Nirenberg says her goggles will convert light into a “neural code,” or a pattern of pre-processed pulses, which will look to the ganglion cells as if they are coming from other cells in the retina. Daniel Palanker, an ophthalmology professor and director of the Hansen Experimental Physics Laboratory at Stanford University, is skeptical that Nirenberg’s neural code will help. That’s because there are around 30 types of retinal ganglion cells, some of which respond to light while some respond to motion and some to differences in contrast. No one set of light patterns would be able to communicate with all of them, he says.


News Article | November 11, 2016
Site: news.yahoo.com

Kids with lazy eye — or amblyopia, the medical term for the condition — may improve their vision by playing a specially designed iPad game, a new study finds. What's more, kids in the study who played the game experienced greater improvements in their vision after just two weeks, compared with those who received the standard treatment for lazy eye, in which the child wears a patch over his or her "good" eye. The findings suggest that treatments for lazy eye that require children to use both eyes, as the iPad game does, "may yield faster gains than patching," the researchers, from a nonprofit eye research institute called the Retina Foundation of the Southwest, in Dallas, wrote in the Nov. 10 issue of the journal JAMA Ophthalmology. Children with lazy eye don't see as well with one of their eyes as they do with the other, and this weaker eye may wander from side to side, according to the Mayo Clinic. About 3 percent of U.S. children have a lazy eye. The standard eye-patch treatment helps to stimulate the weaker eye in kids with lazy eye. Although most children have improved vision after this treatment, it doesn't always work, and some kids experience a return of their lazy eye after the treatment, the researchers said. In addition, children with lazy eye may have trouble using both of their eyes together, so treatments that allow them to use both eyes may work better than those that allow them to use only one of their eyes (as is the case with eye patching), the researchers said. In the new study, the researchers randomly assigned 28 children with lazy eye to either wear an eye patch or undergo treatment with the iPad game. In the game, called Dig Rush, children control characters who are mining for gold, and the goal is to return pieces of gold to a cart as fast as possible while avoiding obstacles, such as monsters. [7 Ways to Short-Circuit Kids' Mobile Addiction] To play the game, the children wear special glasses that affect how the game looks to each eye. The stronger eye sees some elements of the game (such as the gold cart) in reduced contrast, while the weaker eye sees other elements (such as the miner characters) in high contrast.. Both eyes see elements of the background (such as rocks) in high contrast. The children in the iPad group played the game for 1 hour a day, five days a week, for two weeks. Those in the eye-patch treatment group wore an eye patch for 2 hours a day, seven days a week, for two weeks. After two weeks, the children in the iPad group were able to read an average of 1.5 more lines on a letter chart than they could before the treatment, while those in the eye-patch group could read 0.7 more lines on the letter chart, on average, than they could before the treatment. About 40 percent of the children in the iPad group reached 20/32 vision or better (which is near-normal vision), compared with just 7 percent in the eye-patch group. After two weeks, the children in the eye-patch group switched over to the iPad group, and all of the children played the game for another two weeks. After four weeks, there was no difference in vision between the two groups, the researchers found. However, it's still not clear whether the vision improvements in the children after they played the game will last over the long term, the researchers said, so future research is needed to look at that question.


News Article | November 10, 2016
Site: www.sciencedaily.com

A special type of iPad game was effective in treating children with amblyopia (lazy eye) and was more effective than the standard treatment of patching, according to a study published online by JAMA Ophthalmology. Amblyopia is the leading cause of monocular visual impairment in children, affecting 3 percent in the United States. Amblyopia has traditionally been viewed as a monocular disorder that can be treated by patching the fellow (opposite) eye to force use of the amblyopic eye, but it does not always restore 20/20 vision or teach the eyes to work together. Because amblyopia arises from binocular discordance, binocular treatments are likely to yield better vision outcomes. However, it is unclear whether binocular treatment is comparable to patching in treating amblyopia. Krista R. Kelly, Ph.D., of the Retina Foundation of the Southwest, Dallas, and colleagues randomly assigned 28 children (average age, 7 years) with amblyopia to binocular game treatment (n = 14) and to patching treatment (n = 14). The action-oriented adventure iPad game required children to wear special glasses that separate game elements seen by each eye so that reduced-contrast elements are seen by the fellow eye, high-contrast elements are seen by the amblyopic eye, and high-contrast background elements are seen by both eyes. For successful game play, both eyes must see their respective game components. Children were asked to play the game at home for 1 hour a day, 5 days a week for 2 weeks (10 hours total). The primary outcome was change in amblyopic eye best-corrected visual acuity (BCVA) at the 2-week visit. The researchers found that at the 2-week visit, improvement in amblyopic eye BCVA was greater with the binocular game compared with patching, with the average visual acuity improvement after binocular treatment being more than double the improvement found with patching, and this was achieved with less than 50 percent treatment time required for patching (10 vs 28 hours assigned treatment). Five of 13 children (39 percent) with binocular treatment reached 20/32 or better visual acuity compared with 1 of 14 children (7 percent) with patching. At 2 weeks, patching children crossed over to binocular game treatment, and all 28 children played the game for another 2 weeks. At the 4-week visit, no group difference was found in BCVA change, with children who crossed over to the binocular games catching up with children treated with binocular games. "We show that in just 2 weeks, visual acuity gain with binocular treatment was half that found with 6 months of patching, suggesting that binocular treatment may yield faster gains than patching. Whether long-term binocular treatment is as effective in remediating amblyopia as patching remains to be investigated," the authors write.


News Article | November 10, 2016
Site: www.eurekalert.org

A special type of iPad game was effective in treating children with amblyopia (lazy eye) and was more effective than the standard treatment of patching, according to a study published online by JAMA Ophthalmology. Amblyopia is the leading cause of monocular visual impairment in children, affecting 3 percent in the United States. Amblyopia has traditionally been viewed as a monocular disorder that can be treated by patching the fellow (opposite) eye to force use of the amblyopic eye, but it does not always restore 20/20 vision or teach the eyes to work together. Because amblyopia arises from binocular discordance, binocular treatments are likely to yield better vision outcomes. However, it is unclear whether binocular treatment is comparable to patching in treating amblyopia. Krista R. Kelly, Ph.D., of the Retina Foundation of the Southwest, Dallas, and colleagues randomly assigned 28 children (average age, 7 years) with amblyopia to binocular game treatment (n = 14) and to patching treatment (n = 14). The action-oriented adventure iPad game required children to wear special glasses that separate game elements seen by each eye so that reduced-contrast elements are seen by the fellow eye, high-contrast elements are seen by the amblyopic eye, and high-contrast background elements are seen by both eyes. For successful game play, both eyes must see their respective game components. Children were asked to play the game at home for 1 hour a day, 5 days a week for 2 weeks (10 hours total). The primary outcome was change in amblyopic eye best-corrected visual acuity (BCVA) at the 2-week visit. The researchers found that at the 2-week visit, improvement in amblyopic eye BCVA was greater with the binocular game compared with patching, with the average visual acuity improvement after binocular treatment being more than double the improvement found with patching, and this was achieved with less than 50 percent treatment time required for patching (10 vs 28 hours assigned treatment). Five of 13 children (39 percent) with binocular treatment reached 20/32 or better visual acuity compared with 1 of 14 children (7 percent) with patching. At 2 weeks, patching children crossed over to binocular game treatment, and all 28 children played the game for another 2 weeks. At the 4-week visit, no group difference was found in BCVA change, with children who crossed over to the binocular games catching up with children treated with binocular games. "We show that in just 2 weeks, visual acuity gain with binocular treatment was half that found with 6 months of patching, suggesting that binocular treatment may yield faster gains than patching. Whether long-term binocular treatment is as effective in remediating amblyopia as patching remains to be investigated," the authors write. Editor's Note: This research is supported by a grant from the Thrasher Research Fund and from the National Eye Institute. This study was conducted at the Retina Foundation of the Southwest. All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest and none were reported.


Birch E.E.,Retina Foundation of the Southwest | Birch E.E.,Southwestern Medical Center
Progress in Retinal and Eye Research | Year: 2013

Amblyopia is the most common cause of monocular visual loss in children, affecting 1.3%-3.6% of children. Current treatments are effective in reducing the visual acuity deficit but many amblyopic individuals are left with residual visual acuity deficits, ocular motor abnormalities, deficient fine motor skills, and risk for recurrent amblyopia. Using a combination of psychophysical, electrophysiological, imaging, risk factor analysis, and fine motor skill assessment, the primary role of binocular dysfunction in the genesis of amblyopia and the constellation of visual and motor deficits that accompany the visual acuity deficit has been identified. These findings motivated us to evaluate a new, binocular approach to amblyopia treatment with the goals of reducing or eliminating residual and recurrent amblyopia and of improving the deficient ocular motor function and fine motor skills that accompany amblyopia. © 2012 Elsevier Ltd.


Subramanian V.,Retina Foundation of the Southwest | Jost R.M.,Retina Foundation of the Southwest | Birch E.E.,Retina Foundation of the Southwest | Birch E.E.,Southwestern Medical Center
Investigative Ophthalmology and Visual Science | Year: 2013

Purpose. To determine whether fixation instability contributes to reduced visual acuity in amblyopia, we compared fixation instability, quantified by the Nidek MP-1 microperimeter, in amblyopic and nonamblyopic children. Methods. Participants were 89 children (5-17 years old) with strabismus (n = 31), anisometropia (n = 29), or both conditions (n = 29). Fixation instability was measured using the Nidek MP-1 microperimeter, which calculated horizontal and vertical eye position at 25 Hz as the child attempted steady fixation for 30 seconds. Fixation instability was quantified as the 95% bivariate contour ellipse area (95% BCEA), the best-fit ellipse within which 95% of fixation occurred during the 30-second test. BCEA was normalized by log transformation. Results. Children with amblyopia had significantly larger BCEAs for amblyopic eyes (mean = 0.56 log deg2) than fellow eyes (mean = 0.2 log deg2, P < 0.01) and right eyes of normal controls (mean = 0.12 log deg2, P ≤ 0.01). Fixation instability was significantly greater along the horizontal axis of the ellipse for amblyopic (mean = 3.53°) than fellow (mean = 1.98°, P = 0.008), and control (mean = 1.62°, P < 0.001) eyes. Conclusions. Fixation instability in amblyopic eyes of children with strabismus and/or anisometropia, and the associated poor stereoacuity probably is the consequence of decorrelated binocular experience early in life. Longer duration of decorrelated visual experience is associated with increased fixation instability, poorer stereoacuity, and more severe amblyopia. Treatments that minimize the duration of decorrelated visual experience may improve stereoacuity and decrease fixation instability. © 2013 The Association for Research in Vision and Ophthalmology, Inc.


Wen Y.,Retina Foundation of the Southwest | Klein M.,Retina Foundation of the Southwest | Hood D.C.,Columbia University | Birch D.G.,Retina Foundation of the Southwest
Investigative Ophthalmology and Visual Science | Year: 2012

PURPOSE. To compare local functional measures, the multifocal electroretinogram (mfERG) and visual field sensitivity, with a local structural measure, spectral domain (SD) optical coherence tomography (OCT), of receptor damage in patients with retinitis pigmentosa (RP). METHODS. MfERGs, visual fields, and SD-OCT scans were obtained from 10 patients with RP, ranging in age from 23 to 59 years. Average amplitudes, average linear sensitivities, and average layer thicknesses were measured from within the central 3° and from three concentric annuli located between 3° and 8°, 8° and 15°, and 15° and 24°. A computer program aided manual segmentation and calculated OCT thickness in the scans. RESULTS. Within each patient with RP, mfERG amplitude for each circle/annulus was highly correlated with corresponding layer thicknesses in the outer retina (r = 0.88 to 0.99), but not at all correlated with thickness of the inner nuclear layer or total retina. Across all ring eccentricities, relative mfERG amplitude and relative visual field sensitivity were correlated with relative SD-OCT outer retinal thickness. CONCLUSIONS. In patients with RP, preserved cone photoreceptor function measured by mfERG amplitude and visual field sensitivity correlate well with the remaining thickness of the photoreceptor layer. All three measures show comparable relative loss beyond 3° eccentricity. In the fovea, SD-OCT outer retina thickness showed less relative loss than either mfERG or visual field sensitivity. © 2012 The Association for Research in Vision and Ophthalmology, Inc.


Felius J.,Retina Foundation of the Southwest | Felius J.,University of Texas Southwestern Medical Center | Muhanna Z.A.,Retina Foundation of the Southwest
Investigative Ophthalmology and Visual Science | Year: 2013

PURPOSE. Children with idiopathic infantile nystagmus (IIN) exhibit visual acuity deficits that have been modeled in terms of foveation characteristics of the nystagmus waveform. Here we present evidence for an additional component of acuity loss associated with the deprivation experienced during the sensitive period of visual development. METHODS. Binocular grating visual acuity and eye movement recordings were obtained from 56 children with IIN (age 4.8 ± 3.2 years) and documented waveform history from longitudinal visits. Visual acuity was modeled in terms of foveation characteristics (Nystagmus Optimal Fixation Function, NOFF) and of each child's time course of pendular nystagmus during the sensitive period. RESULTS. Mean visual acuity was 0.25 ± 0.19 logMAR below age norms, and the mean foveation fraction was 0.28 (NOFF = -0.9 ± 2.3 logits). Nystagmus had a median onset at age 3 months and transitioned to waveforms with extended foveation at age 35 months. The best fit of the model showed the following: Poor foveation (0.01 foveation fraction) was associated with 0.60 logMAR acuity deficit; this deficit gradually reduced to zero for increasingly better foveation; pendular nystagmus during each decile of the sensitive period was associated with an additional 0.022 logMAR deficit. The model accounted for 57% of the variance in visual acuity and provided a better fit than either component alone. CONCLUSIONS. Visual acuity in IIN is explained better if, besides the child's foveation characteristics, an additional component is taken into account representing the nystagmusinduced visual deprivation during the sensitive period. These findings may have implications for the timing of treatment decisions in children with IIN. © 2013 The Association for Research in Vision and Ophthalmology, Inc.

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