Retinal nerve fiber layer thickness in amblyopia

Purpose: To report retinal nerve fiber layer thickness (RNFLT) in eyes with amblyopia compared with contralateral healthy eyes. Methods: In this cross-sectional study, we included patients with anisometropic amblyopia, strabismic amblyopia, and mixed amblyopia. All subjects underwent complete ophthalmic examination, including RNFLT measurement with time-domain OCT (Stratus OCT) and scanning laser polarimeter (GDX VCC). A paired “t” test was used to compare average and quadrant-wise RNFL thickness between the amblyopic and contralateral normal eyes. In addition, an analysis of variance test was used to compare various RNFL thickness parameters between the three groups. Results: A total of 33 eyes of 33 subjects with anisometropic amblyopia, 20 eyes of 20 subjects with strabismic amblyopia, and 38 eyes of 38 subjects with mixed amblyopia were included. In the anisometropic amblyopia group, the average RNFLT in the amblyopic eye was 98.2 ?m and 99.8 ?m in the fellow normal eye (P = 0.5), the total foveal thickness was 152.82 ?m (26.78) in the anisometropic eye and 150.42 ?m (23.84) in the fellow eye (P = 0.38). The difference between amblyopic and contralateral normal eye for RNFL and macular parameters was statistically insignificant in all three groups. The RNFL thickness in four quadrants was similar in the amblyopic and non-amblyopic eye between all three groups and statistically non-significant. Conclusion: Our study showed that RNFL thickness was similar in amblyopic and non-amblyopic eyes between all three amblyopia groups

Assessment of macular vascular plexus density using optical coherence tomography angiography in cases of strabismic amblyopia

Purpose: To evaluate the superficial retinal vascular plexus density using optical coherence tomography angiography (OCTA) in cases of strabismic amblyopia. Methods: Ten eyes of 10 patients with purely strabismic amblyopia underwent detailed ocular evaluation followed by the assessment of the superficial retinal plexus vascular density using OCTA (Topcon DRI OCT Triton, Swept Source OCT, Topcon, Japan). Ten contralateral normal eyes of the same patients were considered as control. All these 20 eyes underwent a 4.5 × 4.5 mm cube scan OCTA centered at the fovea. Using the Topcon propriety software all 20 eyes were assessed for the capillary plexus density of the superficial retinal vascular plexus along the superior, inferior, nasal, and temporal quadrants centered at the fovea. The numerical values were statistically assessed using a paired t-test with respect to each quadrant between the normal and the pathological eyes. Results: The average age of patients was 16 years and eight patients were males. The mean superficial retinal vascular plexus density along the superior, inferior, nasal, and temporal quadrants in normal and pathological eyes were 49.25 ± 30.34 and 48.93 ± 2.85, 47.22 ± 4.11 and 47.37 ± 4.8, 45.54 ± 1.55 and 43.81 ± 4.21, and 46.26 ± 4.63 and 46.38 ± 5.40, respectively. Similarly, the capillary densities along the central were 17.84 ± 3.49 and 17.24 ± 2.44 in normal and pathological eyes. The differences among all these four quadrants and central area were not statistically significant (P-values > 0.05 for all four quadrants and central area) as compared with the normal eyes. Conclusion: The superficial retinal vascular plexus density of a 4.5 × 4.5 mm cube centered at the fovea of eyes of cases of strabismic amblyopia is similar to that of normal eyes.

Macular Thickness in Moderate to Severe Amblyopia

PURPOSE: To compare the macular retinal thickness of moderately to severely amblyopic eyes with non-amblyopic eyes as controls. METHODS: This case control study was conducted on 56 children aged 4 to 10 years old (64.3% female subjects). Twenty-eight children had unilateral amblyopia (28 amblyopic eyes as cases and 28 normal fellow eyes as internal controls) and 28 children had normal visual acuity in both eyes and were considered as external controls (n = 56 eyes). Among our cases, 14 had strabismic amblyopia and 14 had anisometropic amblyopia. Macular retinal thickness was measured using optical coherence tomography at the center and in 1-, 3-, and 6-mm rings. RESULTS: Best-corrected visual acuity of the amblyopic eyes was less than that of the internal and external controls, and the best-corrected visual acuity of their fellow eyes was also less than that of the external controls. Thickness of the central macula and a 1-mm ring area in the amblyopic eyes was higher than that of both internal and external controls. Difference of central macular thickness ≥20 µm between two eyes of the amblyopic children was significantly more than non-amblyopic subjects. CONCLUSIONS: Based on the results of this study, the macular retinal thickness was significantly higher in moderate to severe amblyopic eyes compared to their fellow eyes and external controls. This might be due to macular developmental disorders in amblyopic eyes. Therefore, optical coherence tomography imaging is recommended if subtle macular abnormalities are suspected in moderate to severe amblyopic eyes.

Effects of L-dopa methyl ester on the strabismic amblyopia cats / 中国药理学通报

Aim To observe the effects of the L-dopa methyl ester (LDME) on the pattern visual evoked potentials (P-VEP) and the expression of c-fos mRNA in neurons of the visual cortex of kittens with strabismic amblyopia, and explore the therapeutic effect of L-dopa methyl ester on amblyopia and its action mechanism.Methods 30 normal kittens were randomly divided into 6 groups: low dose of L-dopa methyl ester (20 mg·kg~(-1)), medium dose of L-dopa methyl ester (40 mg·kg~(-1)), and high dose of L-dopa methyl ester (80 mg·kg~(-1)),positive control (L-dopa 40 mg·kg~(-1)),normal control, and model control group.The surgery for producing iatrogenic convergent strabismus was performed on 4 weeks old kittens(normal control group excluded). After the confirmation of the development of amblyopia by pattern visual evoked potential,L-dopa methyl ester,L-dopa and normal saline were given to the corresponding animals, respectively. The P-VEP of amblyopia eyes was observed after one month, and the technique of in situ hybridization was used to detect the expression of c-fos mRNA.Results L-dopa methyl ester could reduce obviously the length of P100 peak latency of the cat strabismic amblyopes, and increase the amplitude of P100. The positive staining cells of strabismic cat visual cortex were less than those of normal cats, whose difference was significant (P<0.01).Positive staining cells in the treatment group were significantly increased when compared with that of the model group (P<0.01).Conclusion L-dopa methyl ester can significantly improve the conduction and sensory function in the model of strabismic amblyopia cats. The mechanism may be related to the increased amount of L-dopa methyl ester into the cerebral cortex and regulation of the expression of c-fos mRNA.

The evaluation of stereopsis in different types and degrees of amblyopic children / 眼科研究

Objective Amblyopia is common disease in children. It can cause visual suppression that damage binocular vision function especially to the development of stereopsis. The objective of this study was to investigate the stereoscopic vision in children with different types and degrees of amblyopia. Methods This is a clinical retrospective comparative analysis. 178 children with amblyopia from Sichuan Provincial Corps Hospitial CAPF were enrolled in this study. Approximation zero disparity, crossed disparity, uncrossed disparity were examined with Yan' s stereogram. The classification of stereogram based on the criteria of Okuda. The degree of amblyopia was graded based on the corrected vision acuity. Results The differences in the eyes and percentage of approximation zero disparity, crossed disparity, uncrossed disparity among refractive amblyopia group, anisopia amblyopia group and strabismic amblyopia group were statistically significant, respectively(χ~2 =13. 979, P =0. 001; χ~2 = 15. 198, P = 0. 001 ; χ~2 =6. 974, P = 0. 031) . Approximation zero disparity, crossed disparity in mild amblyopia were better than of medium amblyopia in ametropic amblyopic children (P ＜ 0. 05) . No statistically significant difference in the eye number and percentage of uncrossed disparity was found between mild and moderate refractive ametropia (P ＞ 0. 05) . The same outcomes also were seen in approximation zero disparity, crossed disparity, uncrossed disparity between mild and medium anisopia amblyopia (P ＞ 0. 05) . No statistically significant differences in the eye number and percentage of approximation zero disparity, crossed disparity were found between mild and moderate strabismic amblyopia (P ＞0. 05) . Conclusion Amblyopia affects the development of stereoacuity. Amblyopia is aggravated with the increase of amblyopia degrees. The influence of amblyopia on stereoscopic vision is most mild in refractive ametropic and most serious in strabismic amblyopia.

The Effect of L-dopa in Amblyopic Children for Whom Occlusion Therapy Failed

PURPOSE: This study was undertaken to evaluate the effect of L-dopa in amblyopic children for whom occlusion treatment failed. METHODS: We studied nine amblyopic children (11 eyes) for whom part-time occlusion (4~8 hours/day) treatment for a minimum period of 6 months had failed. The types of amblyopia included: anisometropic (1 patient, 1 eye), stimulus deprivation (4 patients, 6 eyes) and mixed (anisometropic and strabismic: 2 patients, 2 eyes; anisometropic and organic: 2 patients, 2 eyes). Best corrected visual acuity before treatment was between 0.05 and 0.5. They received, with full informed consent of the parent, levodopa (2~4 mg/kg) for 8 weeks combined with part-time occlusion. RESULTS: The children were between 4 and 11 years old (mean 5.8+/-2.05). Of the subjects, 45.5% (4 patients, 5 eyes) had improved visual acuity after 8 weeks of treatment. In one patient with anisometropic, two patients with mixed (anisometropic and strabismic), and one patient with stimulus deprivation (ametropic) amblyopia, visual acuity improved by one to five lines. CONCLUSIONS: In anisometropic, strabismic amblyopes and mild deprivational amblyopes for whom occlusion treatment failed, L-dopa improved visual acuity. L-dopa may be an additional option for treatment of amblyopic patients with a guarded visual prognosis.

The Refractive Errors and Axial Length in Amblyopia

PURPOSE: It is the purpose of this study to investigate the distribution of the refractive error between amblyopic and nonamblyopic eye in the strabismic or anisometropic amblyopia and also evaluate the relationship among refractive error, axial length and the depth of amblyopia. METHODS: We prospectively reviewed the corrected best visual acuity, amount of deviation, cycloplegic refractive error and axial length in a total of 65 patients who are 29 strabismic and 36 anisometropic amblyopic patients from February 1999 to June 2001. RESULTS: Hyperopia was detected in as many as 20 of 29 strabismic (69%) and 22 of 36 anisometropic amblyopia (61%). In strabismic amblyopia the depth of amblyopia is correlated with the degree of hyperopia (r=0.535, p=0.022), not with axial length. In anisometropic amblyopia, the depth of amblyopia is correlated with the degree of hyperopia (r=0.689, p=0.000) and the degree of myopia (r=-0.691, p=0.013), and in especially hyperopic anisometropia, it is correlated with axial length (r=0.513, p=0.017). CONCLUSIONS: Hyperopia was the major refractive error in strabismic and anisometropic amblyopia and the depth of amblyopia is correlated with degree of hyperopia. In hyperopic anisometropic amblyopia, the greater the depth of amblyopia, the shorter the axial length.

Therapy of Strabismic Amblyopia less than 0.1 Vision

In amblyopes with visual acuity less than 0.1, it is very hard to obtain visual improvement by antiamblyopia treatment. They show very poor compliance with patching of good eye due to severely blurted vision of amblyopic eye. We experienced 29 children who showed strabismic amblyopia with vision less than 0.1. The treatment includes glasses, patching or patching combined with atropine penalization of good eye, and surgery for strabismus in some cases. The average improvement of visual acuity in 29 children was 4 lines on viusal acuity chart. Twenty three out of 29 patients(79%) obtained visual acuity of 0.3 or more. Among 6 patients who could not show good visual outcome, 5 patients had been lazy in patching therapy. The improvement of visual acuity was not influenced by age of the patients, severity of refractive error and angle of deviation, but compliance with patching. This study reveals that the vigorous and steady patching could considerably improve visual acuity in severe amblyopia, and also needs full understanding and effort of patients, parents and physicians to gain satisfactory result.

The Analysis of Improvement of Visual Acuity by Occlusion Therapy in Strabismic Amblyopia

In an attempt to assess the effect of occlusion to improvement of visual acuity, we analyzed data from 55 patients with strabismic amblyopia(mean; 5.5 years old) who received strabismus surgery with occlusion(combined therapy) or surgery only. The results were as follows: 1. The younger the patients at onset, the better the visual acuity obtained. The improvement in visual acuity was higher in 27 of 32 cases(84.4%) with the combined therapy than in 5 of 18 cases(27.8%) who underwent surgery only, and the difference between those two groups was significant statistically(p<0.05). 2. In exotropes, improvement of visual acuity was shown in 19 of 32 cases(59.3%) and there was no significant difference in the improvement of visual acuity between the intermittent and constant types. 3. In 23 esotropes, 18 patients(78.3%) showed the improvement of visual acuity; 13 of 16 cases in infantile esotropia and all of 7 cases in acquired one. 4. In the final results of surgery, the alignment was satisfactory in 50 of 55 cases(90.9%), showing less than 10 prism diopters. From the results of our study, we confirmed that the occlusion during pre-and postoperative periods is the effective therapy to treat amblyopia in the children with strabismic amblyopia, and its importance was reported.