Anisometropic Amblyopia Group Research Articles

Analyses of eye movement parameters in children with anisometropic amblyopia

ObjectiveTo investigate the characteristics of eye movement in children with anisometropic amblyopia, and to compare those characteristics with eye movement in a control group.Methods31 children in the anisometropic amblyopia group (31 amblyopic eyes in group A, 31 contralateral eyes in group B) and 24 children in the control group (48 eyes in group C). Group A was subdivided into groups Aa (severe amblyopia) and Ab (mild-moderate amblyopia). The overall age range was 6–12 years (mean, 7.83 ± 1.79 years). All children underwent ophthalmic examinations; eye movement parameters including saccade latency and amplitude were evaluated using an Eyelink1000 eye tracker. Data Viewer and MATLAB software were used for data analysis.ResultsMean and maximum saccade latencies, as well as mean and maximum saccade amplitudes, were significantly greater in group A than in groups B and C before and after treatment (P < 0.05). Mean and maximum saccade latencies were significantly different among groups Aa, Ab, and C (P < 0.05). Pupil trajectories in two detection modes suggested that binocular fixation was better than monocular fixation.ConclusionsEye movement parameters significantly differed between contralateral normal eyes and control eyes. Clinical evaluation of children with anisometropic amblyopia should not focus only on static visual acuity, but also on the assessment of eye movement.

Evaluation of Macular Pigment Optical Density in Eyes with Hyperopic Anisometropic Amblyopia Using Fundus Reflectometry.

This study aimed to evaluate the macular pigment optical density (MPOD) scores in eyes with hyperopic anisometropic amblyopia and compare those with their fellow and control eyes using one-wavelength fundus reflectometry. This cross-sectional study enrolled 33 patients diagnosed with hyperopic anisometropic amblyopia aged 12-40 years. The control group consisted of 36 hyperopic and 42 emmetropic children, age-matched to the patients. Central macular thickness (CMT), MPOD, axial length (AL), best-corrected visual acuity, and refraction errors were measured between the study group and the control group. Eyes with the diagnosis of hyperopic anisometropic amblyopia had significantly higher mean and maximum (max) MPOD scores compared with their fellow eyes as well as hyperopic and emmetropic eyes (p<0.001 for all). The mean AL in eyes with hyperopic anisometropic amblyopia was statistically shorter than that in hyperopic and emmetropic controls (p=0.027, p<0.001, respectively). The mean CMT was found to be thicker in eyes with hyperopic anisometropic amblyopia when compared to their fellow eyes, as well as hyperopic and emmetropic controls, eventhough there was no significant difference was found among the four groups (p=0.052). The mean MPOD levels were significantly correlated with the difference in CMT (r=-0.21, p=0.032), and logMAR visual acuity scores (r=-0.44, p<0.001) in the hyperopic anisometropic amblyopia group. The present study indicates that the MPOD is reduced in eyes with hyperopic anisometropic amblyopia. This reduction may be due to less visual stimulus-induced deterioration of foveal development and microarchitecture in anisometropic amblyopic eyes.

Single Center to Evaluate and Compare Anisometropic Amblyopia in Adults Using Blood Oxygenation Level-Dependent Functional Magnetic Resonance Imaging and Diffusion Kurtosis Imaging.

BackgroundAnisometropic amblyopia results from the unequal ability to focus between the right and left eyes. Blood oxygenation level-dependent functional magnetic resonance imaging (BOLD-fMRI) measures the proportion of oxygenated hemoglobin in specific areas. Diffusion kurtosis imaging (DKI) is a method of diffusion tensor imaging that estimates the skewed distribution of water diffusion probability. We aimed to evaluate and compare 11 adult patients with anisometropic amblyopia (AA) with 13 normally sighted healthy controls (HC) using BOLD-fMRI and DKI.Material/MethodsEleven adults with AA (age range 20–49; mean age 29.18±8.089) and 13 HC adults (age range 22–50; mean age 28.00±5.79) were recruited. DKI scanning used a single excitation echo-planar imaging sequence and a region of interest to obtain DKI parameters for optic radiation; the corpus callosum was manually placed, including mean kurtosis (MK), fractional anisotropic (FA), and mean diffusivity (MD) values; and BOLD data used a gradient-echo echo-planar imaging sequence.ResultsThe AA group had lower MK and FA of bilateral optic radiation than the HC group (P=0.008 and P=0.006, respectively) and higher MD than the HC group (P=0.005). The MK of the corpus callosum in the AA group was lower than that of HC group (P=0.012).Compared with the non-dominant eyes of the HC group, the amblyopic eyes in the AA group had less activation range and intensity in Brodmann areas 17, 18, and 19.ConclusionsThe combined use of DKI and BOLD-fMRI detected microstructural changes associated with local visual pathways and identified damage to the visual cortex in patients with amblyopia.

Retinal nerve fiber layer thickness in amblyopia.

To report retinal nerve fiber layer thickness (RNFLT) in eyes with amblyopia compared with contralateral healthy eyes. 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. 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 μm and 99.8 μm in the fellow normal eye (P = 0.5), the total foveal thickness was 152.82 μm (26.78) in the anisometropic eye and 150.42 μm (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. Our study showed that RNFL thickness was similar in amblyopic and non-amblyopic eyes between all three amblyopia groups.

Long-Term Efficacy of the Combination of Active Vision Therapy and Occlusion in Children with Strabismic and Anisometropic Amblyopia.

This retrospective study was conducted to evaluate the efficacy of the combined treatment of occlusion and active vision therapy in a total of 27 amblyopic children, including 14 strabismic and 13 anisometropic cases. For such purpose, changes in distance and near visual acuity as well as in the binocular function was evaluated during a two-year follow-up. In both amblyopia groups, significant improvements were found in distance and near visual acuity in the non-dominant eye (p < 0.001). In the strabismic amblyopia group, the percentage of patients with binocular function score (BF) > 3.3 decreased significantly from a baseline value of 64.3% to a two-year follow-up value of 7.1% (p < 0.001). In the anisometropic amblyopia group, this percentage also decreased significantly from a baseline value of 15.4% to a two-year follow-up value of 0.0% (p < 0.001). No recurrences were observed in the anisometropic amblyopia group, whereas recurrence occurred in two cases of the strabismic amblyopia group after finishing the vision rehabilitation process. In conclusion, the combined approach of the treatment evaluated is efficacious for providing an improvement in visual acuity and binocular function in both anisometropic and strabismic amblyopia, which was maintained over time.

Clinical Aniseikonia in Anisometropia and Amblyopia.

Purpose:Clinically, aniseikonia (a perceived difference in shape and image size between the eyes) is often neglected in anisometropic amblyopia due to assumed measurement difficulties. Therefore, we currently lack evidence on whether correction of aniseikonia is beneficial. This study aimed to determine whether subjective aniseikonia is measurable in anisometropia with or without amblyopia.Methods:Participants (15–52 years) with Anisometropic Amblyopia (n = 7), Anisometropia without amblyopia (n = 6) and Isometropic Controls (n = 6) were recruited. Subjective aniseikonia was measured using three clinical techniques: Robertson Technique (RT) (penlight and Maddox rod), Aniseikonia Inspector Version 3 (AI3), and the New Aniseikonia Test booklet (NAT), and a psychophysical adaptive method, the Contrast-balanced Aniseikonia Test (CAT), where dichoptic contrast adjustments compensate for any suppression.Results:Eighteen participants completed all tests, one Anisometropic Amblyopia participant could only complete the CAT and NAT due to fusion loss. The Anisometropic Amblyopia group exhibited the most aniseikonia (range –1.50–+10.50%) followed by Anisometropic Controls (range –3.30–+4.50%) and Isometropic Controls (range –1.50–+3.28%). There was a significant trend of more subjective aniseikonia with increasing amounts of anisometropia across all four tests (AI3 r = 0.630, p = 0.005; NAT r = 0.542, p = 0.017; RT r = 0.499, p = 0.035; CAT r = 0.440, p = 0.059. Bland Altman analysis demonstrated clinically significant levels of variability between the tests.Conclusions:Subjective aniseikonia can be reliably measured in patients with anisometropia and suppression. Subjective aniseikonia measurement is recommended as four of the most commonly used clinical tests did not support the 1% per dioptre rule of thumb.

Optical Coherence Tomography Analysis of Macular Thickness in Children with Amblyopia

Purpose: To compare central, inner and outer ring macular thickness measured with optic coherence tomography (OCT) in children with unilateral amblyopia. To analyze the differences in retinal structure among strabismic, anisometropic and combined (strabismus + anisometropia) amblyopia. Background: Amblyopia is a reduction of visual acuity in one or both eyes due to an abnormal visual input during the development of the visual system. It is mainly caused by strabismus, anisometropia or high bilateral refractive errors, and visual deprivation. Although it has been always said that the amblyopic eye is an otherwise healthy eye, the imaging techniques developed lately, especially OCT and angio OCT, may show differences in retinal structures that could have a role in the development of amblyopia and/or its response to treatment. Methods: Retrospective review of amblyopic children followed up in our hospital. 60 children with unilateral amblyopia due to anisometropia and/or strabismus, with a good quality OCT exam, were included. We analyzed 9 thickness measurements: central macular thickness (1mm ring) and 4 sectors in inner (3mm) and outer (6mm) rings. Results: Data from 60 children is included. Mean retinal thickness at the central 1mm ring was 249.15µm for amblyopic eyes vs 238.3µm for fellow eye (p=0.000). For the thickness in the other 8 sectors for inner and outer rings no statistically significant differences were found. The central retina measurement was thicker in the anisometropic amblyopia group (p=0.003), but no statistically significant difference was found in the strabismic (p=0.066) and combined group (p=0.055). Conclusions: Central retinal thickness was significantly greater in amblyopic eyes compared to fellow eyes. This difference in thickness is also statistically significant in patients with anisometropia but not in those with strabismus or strabismus + anisometropia. Further studies with more patients are recommended.

Binocular treatment in adult amblyopia is based on parvocellular or magnocellular pathway.

Amblyopia is speculated to be an untreatable disease in the patient, who is beyond the critical period of vision; however, currently, it is treatable in adults. This study aimed to elucidate whether the treatment is useful in both anisometropic amblyopia and strabismic amblyopia. In addition, the differences were detected between anisometropic amblyopia and strabismic amblyopia after the same perceptual treatment and whether the suppression in anisometropic amblyopia or strabismic amblyopia could be decreased before and after the treatment. A binocular perceptual learning was applied for the treatment, the suppression was measured, and the patients were followed up for 2 months after training. Anisometropic amblyopia and strabismic amblyopia groups were subjected to the assessment of stereo, visual acuity, contrast sensitivity, and suppression before and after the training. After 6 weeks of "Diploma Gabor Orientation Coherence" training, in the anisometropic amblyopia group, the outcomes of visual acuity (t = 3.114, p = 0.026) and contrast sensitivity (t = 7.786, p = 0.001) were increased significantly. While in the strabismic amblyopia group, the outcomes of stereo (t = 2.987, p = 0.040) and contrast sensitivity (t = 3.638, p = 0.022) were increased significantly. After Diploma Gabor Orientation Coherence training in the same frequency and in the same duration, the anisometropic amblyopia group got an improvement in visual acuity, but the strabismic amblyopia group got an improvement in stereo. As there are evidences to show that anisometropic amblyopia and strabismic amblyopia were injured in different pathways, we think the diverse results might come from the different pathway injury in anisometropic amblyopia and strabismic amblyopia.

Macular retinal and choroidal thickness in unilateral amblyopia using swept-source optical coherence tomography

BackgroundTo investigate macular retinal and choroidal thickness in amblyopic eyes compared to that in fellow and normal eyes using swept-source optical coherence tomography (SS-OCT).MethodsThis study examined 31 patients with hyperopic anisometropic amblyopia (6.9 ± 3.8 years, mean ± standard deviation), 15 patients with strabismic amblyopia without anisometropia (7.9 ± 4.2 years), and 24 age-matched controls (7.8 ± 3.3 years). Retinal and choroidal thickness was measured by 3D scans using SS-OCT. A 6-mm area around the fovea was automatically analyzed using the Early Treatment Diabetic Retinopathy Study map. The thickness from SS-OCT was corrected for magnification error using individual axial length, spherical refraction, cylinder refraction, and corneal radius. Retinal thickness was divided into the macular retinal nerve fiber layer (mRNFL), ganglion cell layer + inner plexiform layer (GCL+IPL), ganglion cell complex (GCC), and the inner limiting membrane to the retinal pigment epithelium (ILM-RPE) thickness. Retinal and choroidal thickness was compared among amblyopic, fellow, and normal eyes.ResultsIn both amblyopia groups, there was no significant difference in the mRNFL, GCL+IPL, and GCC thicknesses among the amblyopic, fellow, and control eyes. In the anisometropic amblyopia group, choroidal thickness (subfovea, center 1 mm, nasal and inferior of the inner ring, nasal of the outer ring, and center 6 mm) of amblyopic eyes were significantly greater than that of fellow and normal eyes. In contrast, none of the choroidal thicknesses were significantly different among the investigated eyes in the strabismic amblyopia group.ConclusionsWe found no significant difference in inner retinal thickness in patients with unilateral amblyopia. Although there were significant differences in choroidal thickness with hyperopic anisometropic amblyopia, there was no significant difference for the strabismic amblyopia. The discrepancy in choroidal thickness between the two types of amblyopia may be due to both differences in ocular size and underlying mechanism.

Abnormal Spontaneous Brain Activity in Patients With Anisometropic Amblyopia Using Resting-State Functional Magnetic Resonance Imaging.

To explore the abnormality of spontaneous activity in patients with anisometropic amblyopia under resting-state functional magnetic resonance imaging (Rs-fMRI). Twenty-four participants were split into two groups. The anisometropic amblyopia group had 10 patients, all of whom had anisometropic amblyopia of the right eye, and the control group had 14 healthy subjects. All participants underwent Rs-fMRI scanning. Measurement of amplitude of low frequency fluctuations of the brain, which is a measure of the amplitudes of spontaneous brain activity, was used to investigate brain changes between the anisometropic amblyopia and control groups. Compared with an age- and gender-matched control group, the anisometropic amblyopia group showed increased amplitude of low frequency fluctuations of spontaneous brain activity in the left superior temporal gyrus, the left inferior parietal lobe, the left pons, and the right inferior semi-lunar lobe. The anisometropic amblyopia group also showed decreased amplitude of low frequency fluctuations in the bilateral medial frontal gyrus. This study demonstrated abnormal spontaneous brain activities in patients with anisometropic amblyopia under Rs-fMRI, and these abnormalities might contribute to the neuropathological mechanisms of anisometropic amblyopia. [J Pediatr Ophthalmol Strabismus. 2017;54(5):303-310.].

The Initiation of Smooth Pursuit is Delayed in Anisometropic Amblyopia.

PurposeSeveral behavioral studies have shown that the reaction times of visually guided movements are slower in people with amblyopia, particularly during amblyopic eye viewing. Here, we tested the hypothesis that the initiation of smooth pursuit eye movements, which are responsible for accurately keeping moving objects on the fovea, is delayed in people with anisometropic amblyopia.MethodsEleven participants with anisometropic amblyopia and 14 visually normal observers were asked to track a step-ramp target moving at ±15°/s horizontally as quickly and as accurately as possible. The experiment was conducted under three viewing conditions: amblyopic/nondominant eye, binocular, and fellow/dominant eye viewing. Outcome measures were smooth pursuit latency, open-loop gain, steady state gain, and catch-up saccade frequency.ResultsParticipants with anisometropic amblyopia initiated smooth pursuit significantly slower during amblyopic eye viewing (206 ± 20 ms) than visually normal observers viewing with their nondominant eye (183 ± 17 ms, P = 0.002). However, mean pursuit latency in the anisometropic amblyopia group during binocular and monocular fellow eye viewing was comparable to the visually normal group. Mean open-loop gain, steady state gain, and catch-up saccade frequency were similar between the two groups, but participants with anisometropic amblyopia exhibited more variable steady state gain (P = 0.045).ConclusionsThis study provides evidence of temporally delayed smooth pursuit initiation in anisometropic amblyopia. After initiation, the smooth pursuit velocity profile in anisometropic amblyopia participants is similar to visually normal controls. This finding differs from what has been observed previously in participants with strabismic amblyopia who exhibit reduced smooth pursuit velocity gains with more catch-up saccades.

The Morpho-functional Evaluation of Retina in Amblyopia

Purpose: To investigate the morphological or functional differences of retina in amblyopia.Materials and methods: Forty-one patients with unilateral strabismic, anisometropic or combined amblyopia were included in the study. A control group was composed of 16 normal children. All participants were tested with optical coherence tomography (OCT) and pattern electroretinography (PERG). The findings from amblyopic and nonamblyopic eyes were compared among the amblyopic groups. Also, amblyopic and nonamblyopic eyes were compared with the healthy control eyes.Results: No significant difference was found in OCT parameters for amblyopic and nonamblyopic eyes among the amblyopic groups (p > 0.05). In the combined and anisometropic groups, ganglion cell complex (GCC) was found to be significantly increased in both amblyopic and nonamblyopic eyes compared to the control group (p < 0.05). In strabismic amblyopia, significant reduction in GCC thickness and increase in foveal thickness were found, compared to nonamblyopic eyes (p = 0.019, p = 0.08). There were no significant differences in PERG amplitude and latency between the amblyopic and the nonamblyopic eyes in amblyopic groups (p > 0.05). PERG amplitude in amblyopic eyes was found to be significantly decreased compared with that in normal eyes (p < 0.05). When the nonamblyopic eyes were compared with the control group, only the anisometropic amblyopia group demonstrated significant reduction in amplitude and prolongation in latency (p = 0.002, p = 0.026).Conclusion: We found no significant differences in morphological and functional measures among amblyopic groups. However, we detected significant differences in the retinal function and morphology of both amblyopic and nonamblyopic eyes compared with healthy control eyes.

Permanent results of pleoptic treatment

The value of pleoptic treatment was assessed by a long-term follow-up of patients treated 15-22 years ago, employing a questionnaire sent to 232 patients and a clinical examination of a sample of 44 of these. Answers were received from 157 persons with different occupations and educational levels who were fairly representative of the population of Northern Finland as a whole. The treatment was considered beneficial by 62% of these. The primary improvement in the mean visual acuity (VA) from 0.33 to 0.86 among the 44 persons examined proved to be partly transitory, the final mean value being 0.61. The poorest results were found in the combined strabismic and anisometropic amblyopia group. The final VA correlated positively with the initial VA and negatively with age at the time of treatment. Binocular single vision improved the prognosis. Altogether 1/4 of the patients achieved a VA of 1.0 or better, about one half experienced no permanent increase in VA and the remainder were distributed evenly between these two extremes.