Levodopa and childhood amblyopia.

Occlusion and levodopa-carbidopa treatment for childhood amblyopia

Studies in nonhuman primates show that monocular visual deprivation starting at different ages has different effects on cells in the parvocellular and magnocellular laminae of the lateral geniculate nucleus. The present study used color and luminance contrast sensitivity (CS) measurements to look for differences in parvocellular- and magnocellular-related visual function in human subjects with strabismic amblyopia. Fifteen subjects with early- and 14 with late-onset strabismic amblyopia and similar ranges of visual acuity were studied, together with 15 subjects with normal vision. Contrast sensitivities were measured to an equiluminant (L-M cone-modulated) grating with slow onset and an achromatic (L+M cone-modulated) 0.8-cpd grating with rapid onset using an adaptive Luminance and color CS were lower in the amblyopic eyes than in the fellow eyes of all amblyopes. For luminance CS, this was due both to an increase in sensitivity of the fellow eye and to a reduction in sensitivity in the amblyopic eye. Color CS was greatly reduced in the amblyopic and fellow eyes of subjects with strabismic amblyopia of early- and late onset compared with subjects with normal vision. The reduction in color CS compared with luminance CS was significantly greater in eyes with late- rather than early-onset amblyopia. Parvocellular and magnocellular function are differentially affected in the amblyopic and fellow eyes of subjects with strabismic amblyopia. The difference is more marked in late-onset amblyopia than in early-onset amblyopia.

PurposeDichoptic training is becoming a popular tool in amblyopia treatment. Here we investigated the effects of dichoptic demasking training in children with amblyopia who never received patching treatment (NPT group) or were no longer responsive to patching (PT group).MethodsFourteen NPT and thirteen PT amblyopes (6–16.5 years; 24 anisometropic, two strabismus, and one mixed) received dichoptic demasking training for 17 to 22 sessions. They used the amblyopic eye (AE) to practice contrast discrimination between a pair of Gabors that were dichoptically masked by a band-filtered noise pattern simultaneously presented in the fellow eye (FE). Dichoptic learning was quantified by the increase of maximal tolerable noise contrast (TNC) for AE contrast discrimination. Computerized visual acuities and contrast sensitivity functions for both eyes and the Randot stereoacuity were measured before and after training.ResultsTraining improved maximal TNC by six to eight times in both groups, along with a boost of AE acuities by 0.15 logMAR (P < 0.001) in the NPT group and 0.06 logMAR (P < 0.001) in the PT group. This visual acuity improvement was significantly dependent on the pretraining acuity. Stereoacuity was significantly improved by 41.6% (P = 0.002) in the NPT group and 64.2% (P < 0.001) in the PT group. The stereoacuity gain was correlated to the pretraining interocular acuity difference (r = −0.49, P = 0.010), but not to the interocular acuity difference change (r = −0.28, P = 0.15). Training improved AE contrast sensitivity in the NPT group (P = 0.009) but not the PT group (P = 0.76). Moreover, the learning effects in 12 retested observers were retained for 10 to 24 months.ConclusionsDichoptic training can improve, and sometimes even restore, the stereoacuity of amblyopic children, especially those with mild amblyopia (amblyopic VA ≦0.28 logMAR). The dissociation of stereoacuity gain and the interocular acuity difference change suggests that the stereoacuity gain may not result from a reduced interocular suppression in most amblyopes. Rather, the amblyopes may have learned to attend to, or readout, the stimulus information to improve stereopsis.

Background:Stargardt disease, a common form of heredomacular degeneration, leads to severe vision loss. Video game play can act as a positive biofeedback to reinforce visual rehabilitation and fixation training. It can potentially lead to visual improvement. This study was done to explore the possibility of visual improvement using video game stimulation for visual rehabilitation in Stargardt disease.Methods:We evaluated eight patients with Stargardt disease who had nonatrophic retina surrounding the area of degeneration at the macula. They underwent extensive baseline testing to determine their Snellen visual acuity, pattern visual evoked potentials, retinal sensitivity, and fixation analysis with microperimetry, electroretinography, fundus photography, optical coherence tomography, and autofluorescence. They were given 40 h of training with video game play and re-evaluated on all the tests.Results:They showed both subjective and objective evidence of improvement in visual functions and vision-related tasks. Visual acuity (from 0.77 ± 0.29 to 0.71 ± 0.32 logMAR, p = 0.027), contrast sensitivity (from 1.28 ± 0.25 to 1.46 ± 0.17, p = 0.002), and fixation stability (log of bivariate contour ellipse area from 6.67 ± 0.52 to 5.85 ± 0.84, p = 0.022) improved significantly. The retinal sensitivity improved by 0.47 ± 3.39 dB (p = 0.67). Stereopsis and pattern visual evoked potentials showed improvement. A low vision questionnaire documented subjective improvement.Conclusion:Visual stimulation by video game play can result in improvement in visual acuity, fixation pattern, and retinal sensitivity with improvement in vision-related tasks. It can serve as a simple rehabilitatory technique for patients with central vision loss due to Stargardt disease.

The present study aimed to explore temporal frequency discrimination in amblyopia, and the influence of attentional load on amblyopic temporal cognition. Twenty anisometropic amblyopes, 20 strabismic amblyopes and 20 normal subjects were recruited. A flickering disk was used for visual stimuli. A two-alternative, forced-choice staircase paradigm was used to measure the temporal frequency discrimination thresholds of amblyopic eyes, fellow eyes and normal dominant eyes under reference temporal frequencies of 5, 10 and 20 Hz. The just-noticeable differences data were analyzed statistically. In addition, the temporal frequency discrimination thresholds of the subjects were measured under different conditions of attentional load. The changes in temporal frequency discrimination thresholds were compared between amblyopic and normal eyes when attention was loaded. At the reference temporal frequencies of 5 and 10 Hz, temporal thresholds of amblyopic eyes were significantly increased compared with fellow eyes (P<0.05). Regarding strabismic amblyopia, temporal thresholds of fellow eyes were increased compared with normal eyes (P<0.05). However, no correlation was identified between the temporal-frequency discrimination thresholds and the LogMAR visual acuities in amblyopic eyes. In addition, higher attentional load caused greater changes in temporal thresholds in amblyopic eyes, but the situation was not the same for lower attentional load. In conclusion, in the present study a deficit of temporal frequency discrimination in amblyopic eyes and the fellow eyes of strabismic amblyopes was identified. Furthermore, the influence of attentional load on temporal frequency discrimination in amblyopic eyes was increased compared with normal eyes.

Introduction We aim to compare retrobulbar blood flow parameters between the amblyopic eye and the fellow eye in patients with anisometropic amblyopia. Methods Peak systolic velocity (PSV) and end-diastolic velocity (EDV) of the ophthalmic artery (OA), central retinal artery (CRA), and posterior ciliary artery (PCA) were measured by color Doppler imaging (CDI), and the resistivity index (RI) and pulsatility index (PI) were calculated in 62 patients aged 12-40 years with anisometropic amblyopia. Results The mean PSV values of OA, CRA, and PCA in amblyopic and fellow eyes were 30.38 ± 10.34, 8.45 ± 2.27, and 8.03 ± 2.77, and33.73 ± 14.46, 8.35 ± 2.05, and 8.81 ± 2.77, respectively. The mean EDV values of OA, CRA, and PCA in amblyopic and fellow eyes were 6.86 ± 2.64, 1.47 ± 1.59, and 1.94 ± 2.03, and 8.57 ± 4.30, 1.80 ± 1.73, and 2.32 ± 1.20, respectively. The mean RI values of OA, CRA, and PCA in amblyopic and fellow eyes were 0.77 ± 0.10, 0.85 ± 0.14, and 0.78 ± 0.15, and 0.75 ± 0.07, 0.79 ± 0.20, and 0.74 ± 0.13, respectively. OA-PSV and OA-EDV values were significantly lower in the amblyopic eye than in the healthy eye (p < 0.05). OA-RI values were significantly higher (p < 0.05) in the amblyopic eye than in the healthy eye. Conclusions Considering the decrease in PSV and EDV and the increase in RI, which are the blood flow parameters of the amblyopic eye, our study may provide guidance to focus on increasing blood flow in the treatment of amblyopia.

Amblyopia is a common childhood vision disorder with a prevalence of 1.6-3.5% worldwide. It has different causes such as anisometropia, strabismus and visual deprivation. This study aimed to determine the effect of patching operation of the better eye on visual acuity (VA) and contrast sensitivity function (CSF) of the amblyopic eye. Thirty four children (18 boys; 16 girls) with mean age of 6.88±1.48 (SD) years participated in the study. Twenty six children had anisometropic and eight had combined (anisometropia and strabismus) amblyopia. VA and CSF of the subjects were measured through YANG vision tester before and three months after patching therapy.The VA between both eyes and CSF at four spatial frequencies, 1.5,6, 12 and18 cycles per degree (cpd) in two phases, were compared. In the better eye, the best corrected VA did not show any significant difference before and after treatment. In amblyopic eyes, postoperative VA significantly improved (P<0.001). Furthermore, the postoperative CSF at high and low spatial frequencies did not show statistically significant difference, whereas at the medium levels significantly increased(P=0.003, 0.001).VA increased in 64% participants and CSF improved 1.16, 1.57, 3.91 and 2.44 times in 1.5, 6, 12 and 18 spatial frequencies respectively. Complete (VA 20/20) and relative improvement (at least 2 lines) of VA was achieved in 60.61% and 39.39% of amblyopic cases respectively. Based on our results, patching of the better eye in amblyopic children can improve VA and CSF, especially in intermediate frequencies. Therefore, our findings recommend the CSF as an accompanying and complementary test for VA at pre and post patch operation evaluation in amblyopia treatment.

This study aimed to compare ocular wavefront aberrations for pupil diameters of 4 mm and 6 mm, and contrast sensitivity, in eyes with AcrySof IQ and AcrySof Natural intraocular lenses (IOLs). Sixty eyes of 60 patients were enrolled in this prospective randomized study. After phacoemulsification the eyes received either AcrySof IQ SN60WF or AcrySof Natural SN60AT IOLs. One month after surgery, all patients underwent complete ophthalmological examination including corneal topography, wavefront analysis for pupil diameters of 4 mm and 6 mm, and contrast sensitivity measurements with the CSV 1000E instrument under photopic and mesopic conditions with and without glare. There was no statistically significant difference between groups in age, sex or other preoperative ocular characteristics (p > 0.05). Patients with AcrySof IQ IOLs had higher contrast sensitivity at 6 c.p.d. under photopic conditions, at 6 c.p.d. and 18 c.p.d. under mesopic conditions, and at 6 c.p.d., 12 c.p.d. and 18 c.p.d. under mesopic conditions with glare (p < 0.05). Corneal spherical aberration was 0.273 ± 0.074 μm in the AcrySof Natural group and 0.294 ± 0.086 μm in the AcrySof IQ group (p = 0489). Ocular spherical aberration was 0.362 ± 0.141 μm and 0.069 ± 0.043 μm (p < 0.001) for 6-mm diameter pupils and 0.143 ± 0.091 μm and 0.017 ± 0.016 μm (p < 0.001) for 4-mm diameter pupils, with AcrySof Natural and AcrySof IQ IOLs, respectively. There were no significant differences in other higher-order aberrations between the groups (p > 0.05). Aspherical AcrySof IQ IOLs significantly reduced spherical aberration for pupil diameters of both 4 mm and 6 mm and also improved contrast sensitivity more than spherical AcrySof Natural IOLs, especially in mesopic conditions.

The effect of simulated normal and amblyopic higher-order aberrations on visual performance

The aim of the present study was to evaluate whether Zen meditation (a mindfulness-based practice) stimulates visual function and increases retinal and retinal nerve fiber layer (RNFL) thickness. This cross-sectional controlled study included 36 eyes of 18 meditators and 76 eyes of 38 age- and sex-matched healthy non-meditators. The average response of both eyes in each subject was analyzed. All subjects underwent evaluation of high and low contrast visual acuity (using ETDRS charts), contrast sensitivity vision (CSV) using the Pelli Robson chart and CSV 1000E test, color vision (using the Farnsworth and L’Anthony desaturated D15 color tests), stereoscopic vision using the TNO test, and retinal and RNFL thickness using optical coherence tomography (OCT). Differences in visual function and RNFL thickness were compared between groups. Our results indicated that meditators exhibited significantly better visual acuity with the three contrast levels used and significantly better contrast sensitivity vision (CSV 1000E) than healthy non-meditators (p ≤ 0.05). Retinal and RNFL structural measurements did not differ significantly between groups. Ganglion cell layer thickness was moderately correlated with visual acuity, CSV, color vision, and stereoscopic vision (p ≤ 0.05; r > 0.6). In conclusion, visual function was enhanced in meditators without significant alterations in the retinal morphologic structure. Further studies are needed to determine whether there is a causal association between mindfulness and visual function improvement.

IntroductionAmblyopia is a neurodevelopmental vision disorder typically affecting one eye, resulting in compromised binocular function. While evidence-based treatments exist for children, there are no widely accepted treatments for adults. This...

ObjectiveAcupuncture has certain effects to improve myopia visual function, but its neural mechanism is unclear. In this study, we acupunctured at the right Taiyang acupoint of myopic patients to analyze the effects of acupuncture on visual function and electroencephalographic activity and to investigate the correlation between improvements in visual function and changes in the brain.MethodsIn this study, a total of 18 myopic patients were recruited. The contrast sensitivity (CS) of the subjects was examined before and after acupuncture, and electroencephalography (EEG) data of the entire acupuncture process were recorded.ResultsThe study found that compared with before acupuncture, the CS of both eyes in myopic patients at each spatial frequency was increased after acupuncture; compared with the resting state, the contribution of microstate C was decreased during the post-acupuncture state, and the transition probability between microstate A and microstate C was reduced; in addition, the contribution of microstate C was negatively correlated with CS at both 12 and 18 cpd.ConclusionThe contrast sensitivity of myopic patients was improved after acupuncture at the Taiyang acupoint (20 min), which may be related to microstate C.

Near vision contrast sensitivity after photorefractive keratectomy

Effects of flurbiprofen and indomethacin on acute cystoid macular edema after cataract surgery: Functional vision and contrast sensitivity

In recent years, a theory has been advanced that corneal asphericity in and of itself determines visual function; that the natural, optimal shape of the cornea is prolate; and that changing the cornea from prolate to oblate negatively impacts visual results. This article presents an analysis of the impact of corneal asphericity on wavefront-guided LASIK. A retrospective analysis was conducted of 160 myopic eyes that had undergone wavefront-guided LASIK. Surgical procedures and data collection were conducted at six clinical sites. Corneal topography, visual acuity, and contrast sensitivity data were collected before and 6 months after surgery. The topographically measured corneal surface of each eye was fitted to a conic, and a Q-value was computed for a 5.5-mm pupil. Multivariate regression analysis was performed to evaluate the correlation between Q-value and visual function. The relationship of changes in the corneal surfaces to visual performance was also investigated. Preoperative corneas exhibited negative (prolate) conic shape constants. Postoperative corneas were about equally divided between positive (oblate) and negative conics. There was no statistically significant correlation between corneal shape and visual acuity or contrast sensitivity function. Changes in corneal asphericity after surgery had no significant correlation with changes in visual acuity or contrast sensitivity. Visual acuity and contrast sensitivity after wavefront-guided LASIK are not dependent on corneal asphericity. Neither preserving nor inducing asphericity ensures better visual outcome. Better visual outcomes are more likely to result from the application of a customized shape than a standard conic shape.