Anisometropic Amblyopic Patients Research Articles

Quantitative comparison of binocular suppression of patients with anisometropic amblyopia and ametropic amblyopia

Objective: To explore the differences in clinical characteristics and interocular interactions between patients with anisometropic amblyopia and ametropic amblyopia. Methods: Cross-sectional study. The newly diagnosed anisometropic (the binocular difference in spherical equivalent≥1.00 D) amblyopia patients and ametropic amblyopia patients (aged 4 to 6 years) in Beijing Tongren Hospital from January 2020 to December 2022 were involved. Patients were further categorized by the refractive status after cycloplegia, including hyperopia, myopia, astigmatism, hyperopia with astigmatism, myopia with astigmatism, mild anisometropia and severe anisometropia. Quantitative measurements of best-corrected visual acuity (logMAR), stereoacuity (transformed to log units), perceptual eye position and interocular suppression were performed, and the differences between groups were analyzed. The rank sum test was used for statistical evaluation. Results: The average age of 45 ametropic amblyopia patients (21 males and 24 females) and 84 anisometropic amblyopia patients (48 males and 36 females) was 5.0 (4.0, 5.0) years and 5.0 (4.0, 6.0) years, respectively. The interocular differences in spherical equivalent [2.56 (1.50, 4.19) D vs. 0.25 (0.13, 0.56) D] and best-corrected visual acuity [0.40 (0.18, 0.70) logMAR vs. 0.07 (0.00, 0.12) logMAR] were larger in patients with anisometropic amblyopia than those with ametropic amblyopia. The anisometropic amblyopia patients had worse stereoacuity [2.60 (2.00, 2.90) log arcsec vs. 2.00 (2.00, 2.30) log arcsec] and deeper suppression [20.0% (13.3%, 40.0%) vs. 10.0% (0, 23.3%)], compared with the ametropic amblyopia patients. The differences were all statistically significant (P<0.05). The suppression and stereoacuity between patients with hyperopic anisometropic amblyopia [suppression, 30.0% (17.5%, 50.0%); stereoacuity, 2.90 (2.30, 2.90) log arcsec] and astigmatic anisometropic amblyopia [suppression, 10.0% (0, 20.0%); stereoacuity, 2.00 (2.00, 2.30) log arcsec] were significantly different (P<0.05). The differences of suppression and stereoacuity between patients with severe (binocular difference in spherical equivalent>2.50 D) [suppression, 30.0% (20.0%, 53.3%); stereoacuity, 2.90 (2.57, 2.90) log arcsec] and mild anisometropia [suppression, 20.0% (0, 30.0%); stereoacuity, 2.00 (2.00, 2.90) log arcsec] were also statistically significant (P<0.05). Conclusions: Patients with anisometropic amblyopia have deeper binocular suppression, worse stereoacuity and more severe binocular interaction abnormality than those with ametropic amblyopia. The severity of anisometropia affects the degree of the interaction abnormality.

Structural and functional alterations in the brains of patients with anisometropic and strabismic amblyopia: a systematic review of magnetic resonance imaging studies.

Amblyopia is the most common cause of vision loss in children and can persist into adulthood in the absence of effective intervention. Previous clinical and neuroimaging studies have suggested that the neural mechanisms underlying strabismic amblyopia and anisometropic amblyopia may be different. Therefore, we performed a systematic review of magnetic resonance imaging studies investigating brain alterations in patients with these two subtypes of amblyopia; this study is registered with PROSPERO (registration ID: CRD42022349191). We searched three online databases (PubMed, EMBASE, and Web of Science) from inception to April 1, 2022; 39 studies with 633 patients (324 patients with anisometropic amblyopia and 309 patients with strabismic amblyopia) and 580 healthy controls met the inclusion criteria (e.g., case-control designed, peer-reviewed articles) and were included in this review. These studies highlighted that both strabismic amblyopia and anisometropic amblyopia patients showed reduced activation and distorted topological cortical activated maps in the striate and extrastriate cortices during task-based functional magnetic resonance imaging with spatial-frequency stimulus and retinotopic representations, respectively; these may have arisen from abnormal visual experiences. Compensations for amblyopia that are reflected in enhanced spontaneous brain function have been reported in the early visual cortices in the resting state, as well as reduced functional connectivity in the dorsal pathway and structural connections in the ventral pathway in both anisometropic amblyopia and strabismic amblyopia patients. The shared dysfunction of anisometropic amblyopia and strabismic amblyopia patients, relative to controls, is also characterized by reduced spontaneous brain activity in the oculomotor cortex, mainly involving the frontal and parietal eye fields and the cerebellum; this may underlie the neural mechanisms of fixation instability and anomalous saccades in amblyopia. With regards to specific alterations of the two forms of amblyopia, anisometropic amblyopia patients suffer more microstructural impairments in the precortical pathway than strabismic amblyopia patients, as reflected by diffusion tensor imaging, and more significant dysfunction and structural loss in the ventral pathway. Strabismic amblyopia patients experience more attenuation of activation in the extrastriate cortex than in the striate cortex when compared to anisometropic amblyopia patients. Finally, brain structural magnetic resonance imaging alterations tend to be lateralized in the adult anisometropic amblyopia patients, and the patterns of brain alterations are more limited in amblyopic adults than in children. In conclusion, magnetic resonance imaging studies provide important insights into the brain alterations underlying the pathophysiology of amblyopia and demonstrate common and specific alterations in anisometropic amblyopia and strabismic amblyopia patients; these alterations may improve our understanding of the neural mechanisms underlying amblyopia.

Evaluation of Choroidal Vascular Structure in Hyperopic Anisometropic Amblyopia.

The aim of the study was to investigate the choroidal structure of patients with anisohypermetropic amblyopia compared to that of healthy eyes in controls of the same age. The study comprises three groups: One group was the amblyopic eyes of patients with anisometropic hypermetropia (AE group), another group was the fellow eyes of patients with anisometropic hypermetropia (FE group), and a final group of healthy controls. Both the choroidal thickness (CT) and choroidal vascularity index (CVI) values were obtained using the spectral-domain optical coherence tomography (OCT) method of improved depth imaging (EDI-OCT; Heidelberg Engineering GmbH, Spectralis, Germany, Heidelberg). This study included 28 anisometropic amblyopic patients (AE and FE groups) and 35 healthy controls. Regarding the distribution of ages and sexes (p=0.813 and p=0.745), the groups were the same. The mean best-corrected visual acuity in AE, FE, and the control group was 0.58±0.76, 0.008±1.30, and 0.004±1.20 logMAR units, respectively. There was a significant difference in terms of CVI, luminal area (LA), and all the CT values between groups. Post hoc univariate analyses indicated that CVI and LA were significantly higher in AE compared to FE and the control group (p<0.05, for each). The temporal, nasal, and subfoveal CT values were considerably higher in AE compared to FE and the control groups (p<0.05, for each). However, there was no difference between FE and the control group (p>0.05, for each). The AE group had larger LA, CVI, and CT values compared to the FE and control groups. These results show that choroidal changes in amblyopic eyes in children are permanent in adulthood if untreated and are involved in the pathogenesis of amblyopia.

Macular pigment optical density of hyperopic anisometropic amblyopic patients measured by fundus reflectometry.

PurposeHyperopic anisometropia is a major cause of amblyopia and may be associated with macular pigment optical density (MPOD) reduction. To explore whether the MPOD changes in hyperopic anisometropic amblyopia, we measured the MPOD using fundus reflectometry in eyes with hyperopic anisometropic amblyopia and normal vision.MethodsThis was a cross-sectional study conducted from January 2017 to June 2017. Forty subjects (25 males and 15 females) between the ages of 6 and 10 years were recruited. The subjects' eyes were divided into two groups: amblyopic eyes (best-corrected visual acuity (BCVA) not more than 20/25 or BCVA of two eyes differing by two or more lines) and fellow eyes. All enrolled subjects underwent a comprehensive ophthalmic examination, including extraocular motility assessment, cover-uncover testing, and refractive error (noncycloplegic), BCVA, axial length (AL), macular foveal thickness (MFT) and MPOD (Visucam® 200, Carl Zeiss Meditec AG, Germany).ResultsThe MPOD of amblyopic and fellow eyes was 0.12 ± 0.03 log units and 0.13 ± 0.04 log units, respectively, with a significant difference (P = 0.026). The MFT of amblyopic and fellow eyes was 241.28 ± 13.95 and 237.13 ± 16.02 μm, respectively, revealing that the MFT was significantly higher in amblyopic eyes than in fellow eyes (P = 0.028). Conversely, there was no correlation between the MPOD and MFT in the two groups.ConclusionsThis study is the first to report that the MPOD is decreased in hyperopic anisometropic amblyopia. In this study, no correlation between the MPOD and MFT was found. In the future, factors that induce a decrease in the MPOD in eyes with hyperopic anisometropic amblyopia should be explored in a large-sample study with follow-up observation.

How does anisometropia affect the choroidal vascularity index?

Purpose:To investigate the choroidal vascularity index (CVI) and morphological features of the choroid in anisometropic amblyopia.Methods:In this prospective cross-sectional study, 39 patients with unilateral anisometropic amblyopic patients and 33 eyes of 33 healthy control participants were involved. These participants were examined in terms of axial length (AL), spherical equivalent (SE), central macular thickness (CMT), choroidal thickness (CT), total choroidal area (TCA), luminal area (LA), stromal area (SA), LA/SA ratio, and CVI. All parameters were compared between amblyopic eyes, healthy fellow eyes, and healthy control eyes. The Shapiro–Wilk tests, Chi-square test, the paired t-test, Wilcoxon signed-rank test, Mann–Whitney U test, Kruskal–Wallis test, and Pearson/Spearman correlation tests were used.Results:In the hyperopic patients; SE, subfoveal CT, nasal CT, temporal CT, TCA, LA, SA, and CMT were greater in amblyopic eyes than in healthy fellow eyes and control eyes (P < 0.001, P < 0.001, P < 0.001, P < 0.001, P < 0.001, P < 0.001, and P < 0.001, respectively), and CVI, LA/SA ratio, and AL were smaller in amblyopic eyes than in healthy fellow eyes and control eyes ([P < 0.001, P = 0.006], P < 0.001, and P < 0.001, respectively). In the myopic patients, subfoveal CT, nasal CT, temporal CT, TCA, LA, SA values were statistically smaller in amblyopic eyes than in healthy eyes and control eyes ([P < 0.001, P = 0.002), [P = 0.004, P = 0.012], [P = 0.012, P = 0.032], [P < 0.001, P = 0.013], [P < 0.001, P = 0.024], and [P < 0.001, P = 0.047], respectively). The differences in the AL and choroidal parameters were due to myopia and hyperopia.Conclusion:The choroidal structural parameters of the amblyopic eyes were different from that of the healthy eyes.

Posterior Pole Asymmetry Analysis in the Children with Anisometropia.

Objectives:The objectives of the study were to investigate the inter and intraocular differences in posterior pole asymmetry analysis (PPAA) with optical coherence tomography (OCT) in anisometropia, to examine the relationship between the presence of anisometropia and amblyopia and retinal thickness.Methods:Patients between ages of 5 and 16 years with anisometropia who applied to our clinic were included in the study. Macular retinal thickness measurements were evaluated by PPAA using the posterior pole algorithm of the spectral domain-OCT device. Asymmetry was analyzed both as the difference between the right and left eyes and the difference between the superior, inferior, and mean retinal thicknesses of 64 separate quadrants in the same eye. Hemispheric and right-left eye asymmetry differences analyses were performed.Results:118 patients were included in the study(65 females and 53 males). Group 1 consisted of anisometropic patients (n=46), Group 2 consisted of anisometropic amblyopia patients (n=40), and Group 3 consisted of control group (n=32). The mean age of the patients was 9.72±5.6 years. The mean spherical equivalent difference between the two eyes of the patients was 1.7±0.6 D. When anisometropic eyes were compared with normal eyes, there was no significant difference between mean superior, inferior and total retinal thickness, and right-left eye asymmetry values (for all, p>0.05). In the asymmetry evaluation performed by counting the black boxes in the PPAA, a significant difference was found in the right-left asymmetry evaluation in anisometropic amblyopic eyes, in some quadrants and in the right-left asymmetry analysis (p<0.05).Conclusion:While no difference was found between anisometropic and normal eyes in the PPAA, there was differences in some quadrants in the anisometropic amblyopic group compared to the control group suggesting that there is an involvement in the peripheral quadrants of the macula, especially in treatment resistant amblyopic patients.

Development of a quality of life questionnaire for adults with anisometropic amblyopia

Objective: To develop and validate the health-related quality of life (HRQOL) questionnaire for adult patients with anisometropic amblyopia. Methods: Cross-sectional study. A total of 170 adult patients with anisometropic amblyopia, 100 adult patients with other eye diseases and 80 healthy adults with normal vision were recruited at the First Affiliated Hospital of Nanjing Medical University, and 20 healthy adults with normal vision were recruited at Qinhuai Medical District of Easter Theater General Hospital of PLA from December 2019 to February 2020. Individual interviews of 30 adult patients with anisometropic amblyopia generated 80 questionnaire items. For item reduction, 40 adult patients with anisometropic amblyopia were asked to complete the 80-item questionnaire and responses were analyzed. Then factor analyses were performed to identify prominent factors (subscales). The reliability of the questionnaire was evaluated by Cronbach's α coefficient. The overall and sub-scale scores were the average scores of all included items, ranging from 0 (worst HRQOL) to 100 (best HRQOL). The final 20-item questionnaire was administered to additional 100 adult patients with anisometropic amblyopia, 100 adult patients with other eye diseases and 100 visually normal adults. Mean overall and subscale scores were compared across groups using one-way analysis of variance. Results: The final adult anisometropic amblyopia questionnaire (AAAQ) consisted of a function subscale and a psychosocial subscale, each containing 10 items. The Cronbach's α coefficients of the overall, function subscale and psychosocial subscale were 0.88, 0.78 and 0.78. There were 55 males and 45 females in 100 adult anisometropic amblyopia patients, with a median age of 26 years (range, 18 to 43 years). The age and gender distribution were matched with 100 adult patients with other eye diseases and 100 healthy adults with normal vision (all P>0.05). The mean overall score (28.63±9.18), function subscale score (27.69±9.88) and psychosocial subscale score (29.53±9.90) for adult patients with anisometropic amblyopia were significantly lower compared to adult patients with other eye diseases (71.28±8.14, P<0.01; 65.56±7.81, P<0.01; 76.85±10.76, P<0.01) and visually normal adults (84.54±9.13, P<0.01; 81.70±9.27, P<0.01; 87.38±10.06, P<0.01). Conclusion: The AAAQ meets the requirements for validity and reliability of a HRQOL questionnaire, and can be used to assess the HRQOL of adult patients with anisometropic amblyopia. (Chin J Ophthalmol, 2021, 57: 341-347).

Reduced evoked activity and cortical oscillations are correlated with anisometric amblyopia and impairment of visual acuity

Amblyopia is a developmental disorder associated with abnormal visual experience during early childhood commonly arising from strabismus and/or anisometropia and leading to dysfunctions in visual cortex and to various visual deficits. The different forms of neuronal activity that are attenuated in amblyopia have been only partially characterized. In electrophysiological recordings of healthy human brain, the presentation of visual stimuli is associated with event-related activity and oscillatory responses. It has remained poorly understood whether these forms of activity are reduced in amblyopia and whether possible dysfunctions would arise from lower- or higher-order visual areas. We recorded neuronal activity with magnetoencephalography (MEG) from anisometropic amblyopic patients and control participants during two visual tasks presented separately for each eye and estimated neuronal activity from source-reconstructed MEG data. We investigated whether event-related and oscillatory responses would be reduced for amblyopia and localized their cortical sources. Oscillation amplitudes and evoked responses were reduced for stimuli presented to the amblyopic eye in higher-order visual areas and in parietal and prefrontal cortices. Importantly, the reduction of oscillation amplitudes but not that of evoked responses was correlated with decreased visual acuity in amblyopia. These results show that attenuated oscillatory responses are correlated with visual deficits in anisometric amblyopia.

Evaluation of Bruch’s membrane opening-minimum rim width and retinal nerve fiber layer thickness in adults with anisometropic amblyopia

To investigate the relationship between Bruch's membrane opening-minimum rim width (BMO-MRW) and retinal nerve fiber layer thickness (RNFLT) in adult patients anisometropic amblyopia using spectral domain optical coherence tomography (SD-OCT). In this cross-sectional, observational study, 43 anisometropic eyes with corresponding fellow eyes. BMO-MRW (shortest distance from BMO to the internal limiting membrane) and peripapillary RNFLT were obtained with Spectral Domain Optic Coherence Topography (SD-OCT). Global and six sectors values according to the legacy distribution of the SD-OCT (nasal [N], nasal superior [NS], temporal superior [TS], temporal [T], temporal inferior [TI], and nasal inferior [NI]) for both RNFLT and BMO-MRW were evaluated. Mean RNFLT and BMO-MRW measurements comparison showed no significance between anisometropia and fellow eyes. In correlation analyses ; although all sectors showed significant positive correlations; the global, TS and NI BMO-MRW sectors were significantly correlated with their corresponding RNFLT within both anisometropia and fellow eyes. In subgroup caparison analyses RNFLT and BMO-MRW showed no differences between amblyopia and fellow eyes. On subgroups correlation analyses, there were not a consistent correlation sectors between RNFLT and BMO-MRW. In the analysis of the BMO-MRW and RNFLT measurements obtained by SD-OCT in adult anisometropic amblyopia patients, both parameters were evaluated not significant on showing structural changes. In correlation analysis within amblyopic and fellow eye groups, while there was positive correlation on all sectors, statistically significant relationships were detected in global, NI, TS sectors for both BMO-MRW and RNFLT measurements.

Effect of keratorefractive surgery on choroidal thickness in anisometropic amblyopia

To evaluate postoperative change in choroidal thickness (CT) in patients with anisometropic amblyopia undergoing keratorefractive surgery. Anisometropic amblyopic patients and nonamblyopic patients who underwent keratorefractive surgery were included in the study. The eyes were divided into three groups. Group 1 consisted of eyes with anisometropic amblyopia, group 2 were the nonamblyopic fellow eyes, and group 3 (control group) were nonamblyopic eyes which had undergone keratorefractive surgery. At the third postoperative month, the CT of these eyes were measured by Enhanced Depth Imaging OCT (EDI-OCT). The choroidal thickness (CT) was measured in the subfoveal area and at 500 micron intervals nasally and temporally. Twenty-three anisometropic amblyopia patients with amblyopic and fellow eyes and 23 control eyes were enrolled. The mean subfoveal choroidal thickness (CT) was 387.3±168.8μm in group 1, 412.2±88.8μm in group 2 and 337.3±99μm in group 3 (P: 0.019). Group 1 and group 2 showed higher choroidal thickness (CT) in the nasal and temporal quadrants than group 3 (P: 0.03, P: 0.04). At the third postoperative month, central foveal choroidal thickness was 356.6±115.5μm in group 1, 375.1±112.5μm in group 2 and 284.4±98.9μm in group 3 (P: 0.071). Choroidal thickness (CT) in the nasal and temporal quadrants at the third postoperative month was also similar (P: 0.210, P: 0.103). The macular choroid is thicker in amblyopic eyes and non-amblyopic fellow eyes than in the nonamblyopic controls. Improved fixation after refractive surgery may normalize CT.

Quantitative analysis of macular and peripapillary microvasculature in adults with anisometropic amblyopia

The aim of this study was to compare the macular and peripapillary capillary vessel density (CVD) and foveal avascular zone (FAZ) in amblyopic eyes of adults with their fellow eyes and with eyes of healthy controls using optical coherence tomography-angiography (OCT-A). A total of 34 eyes of 17 patients with anisometropic amblyopia and 80 eyes of 40 age- and gender-matched healthy controls were included. CVD in superficial (SCP) and deep retinal capillary plexuses (DCP), peripapillary region, and FAZ were analyzed by OCT-A. The median ages were 31years (range 20-64) in patients with amblyopia and 34.5years (range 24-65) in healthy controls (p = 0.242). The mean FAZ area measured was 0.329 ± 0.024mm2 in amblyopic eyes, 0.332 ± 0.025mm2 in fellow eyes, and 0.269 ± 0.015mm2 in control eyes (p < 0.05). The amblyopic eye of participants showed a decrease in CVD of SCP and DCP (p < 0.001, for all). The inside optic disk CVD measurements were lower in the amblyopic eyes than in the fellow eyes (p = 0.001) and healthy subjects (p = 0.015). Significant differences in macular and peripapillary microvasculature were found in anisometropic amblyopic patients. The clinical significance of the results requires further investigation.

Abnormal intra-network architecture in extra-striate cortices in amblyopia: a resting state fMRI study

BackgroundAmblyopia (lazy eye) is one of the most common causes of monocular visual impairment. Intensive investigation has shown that amblyopes suffer from a range of deficits not only in the primary visual cortex but also the extra-striate visual cortex. However, amblyopic brain processing deficits in large-scale information networks especially in the visual network remain unclear.MethodsThrough resting state functional magnetic resonance imaging (rs-fMRI), we studied the functional connectivity and efficiency of the brain visual processing networks in 18 anisometropic amblyopic patients and 18 healthy controls (HCs).ResultsWe found a loss of functional correlation within the higher visual network (HVN) and the visuospatial network (VSN) in amblyopes. Additionally, compared with HCs, amblyopic patients exhibited disruptions in local efficiency in the V3v (third visual cortex, ventral part) and V4 (fourth visual cortex) of the HVN, as well as in the PFt, hIP3 (human intraparietal area 3), and BA7p (Brodmann area 7 posterior) of the VSN. No significant alterations were found in the primary visual network (PVN).ConclusionOur results indicate that amblyopia results in an intrinsic decrease of both network functional correlations and local efficiencies in the extra-striate visual networks.

Characteristics of Anisometropic Patients with and without Strabismus.

Objectives:To evaluate the risk factors for strabismus in patients with anisometropia by comparing degree of anisometropia, depth of amblyopia, and binocular visual function in anisometropic patients with and without strabismus.Materials and Methods:Sixty-five anisometropic patients older than 5 years with amblyopia in one eye who were followed in the Ankara University Faculty of Medicine, Department of Ophthalmology, Pediatric Ophthalmology and Strabismus Unit between May 2009 and April 2010 were included in this study. There were 27 cases of strabismus. The depth of amblyopia, degree of anisometropia, and binocular visual function were assessed in anisometropic cases with and without strabismus.Results:The 65 patients with anisometropia were divided into two groups: 27 patients with strabismus (group 1) and 38 patients without (group 2). Depth of amblyopia was greater in patients with strabismus compared to those without (p=0.006). In patients with strabismus, there was no correlation between angle of deviation and depth of amblyopia (p=0.453). In anisometropic amblyopia patients without strabismus, there was a positive correlation between depth of anisometropia and depth of amblyopia (p=0.35, Pearson’s correlation coefficient=0.343). Comparison in terms of anisometropia showed that patients with strabismus had significantly larger spherical difference between the two eyes than in patients without strabismus (p=0.000, Mann-Whitney U test). There was no significant difference in terms of cylindrical values (p=0.146, Mann-Whitney U test). There was no statistically significant difference in the presence of fusion between anisometropic patients with and without strabismus.Conclusion:The risk of developing strabismus increased as degree of anisometropia increased in anisometropic cases. In addition, depth of amblyopia was greater in anisometropic patients with strabismus.

Distant stereoacuity in children with anisometropic amblyopia.

To characterize changes in distant stereoacuity using Frisby-Davis Distance test (FD2) and Distant Randot test (DR) during treatment for anisometropic amblyopia, to determine factors that influence posttreatment stereoacuity and to compare the two distant stereotests. Fifty-eight anisometropic amblyopic patients with an interocular difference of ≥1.00 diopter who achieved the visual acuity 20/20 following amblyopia treatment were retrospectively included. Stereoacuity using FD2 and DR for distant and Titmus test for near measurement were assessed and compared at the initial, intermediate, and final visit. Multivariate regression models were used to identify factors associated with initial and final stereoacuity. The two distant stereotests revealed a significant improvement in distant stereoacuity after successful amblyopia treatment. Distant stereoacuity using FD2 showed the greatest improvement during the follow up period. The number of nil scores was higher in DR than FD2 at each period. In multivariate analysis, better final stereoacuity was associated with better initial amblyopic eye acuity in both distant stereotests, but not in the Titmus test. Comparing the two distant stereotests, final stereoacuity using FD2 was associated with initial stereoacuity and was moderately related with the Titmus test at each period, but final stereoacuity using DR was not. Distant stereoacuity measured with both FD2 and DR showed significant improvement when the visual acuity of the amblyopic eye achieved 20/20. Changes in distant stereoacuity by FD2 and DR during the amblyopia treatment were somewhat different.

Altered interhemispheric functional connectivity in patients with anisometropic and strabismic amblyopia: a resting-state fMRI study.

Altered brain functional connectivity has been reported in patients with amblyopia by recent neuroimaging studies. However, relatively little is known about the alterations in interhemispheric functional connectivity in amblyopia. The present study aimed to investigate the functional connectivity patterns between homotopic regions across hemispheres in patients with anisometropic and strabismic amblyopia under resting state. Nineteen monocular anisometropic amblyopia (AA), 18 strabismic amblyopia (SA), and 20 normal-sight controls (NC) were enrolled in this study. After a comprehensive ophthalmologic examination, resting-state fMRI scanning was performed in all participants. The pattern of the interhemispheric functional connectivity was measured with the voxel-mirrored homotopic connectivity (VMHC) approach. VMHC values differences within and between three groups were compared, and correlations between VMHC values and each the clinical variable were also analyzed. Altered VMHC was observed in AA and SA patients in lingual gyrus and fusiform gyrus compared with NC subjects. The altered VMHC of lingual gyrus showed a pattern of AA > SA > NC, while the altered VMHC of fusiform gyrus showed a pattern of AA > NC > SA. Moreover, the VMHC values of lingual gyrus were positively correlated with the stereoacuity both in AA and SA patients, and the VMHC values of fusiform gyrus were positively correlated with the amount of anisometropia just in AA patients. These findings suggest that interhemispheric functional coordination between several homotopic visual-related brain regions is impaired both in AA and SA patients under resting state and revealed the similarities and differences in interhemispheric functional connectivity between the anisometropic and strabismic amblyopia.

Is There a Critical Period for Amblyopia Therapy? Results of a Study on Older Anisometropic Amblyopes

Amblyopia, a common cause of low vision, is rarely treated in adults. Improvement in vision has been seen beyond the critical period at times. Hence, this study was taken up to study the effect of minimal occlusion therapy (2-4 hours/day) in anisometropic amblyopic patients in the age group of 12-30 years. The study is a prospective, randomized case series of anisometropic amblyopia patients aged 12-30 years who reported in the outpatient department of Hakeem Abdul Hameed Centenary Hospital, New Delhi, from December 2011 to November 2013. Thorough ocular examination and cycloplegic refraction was done to rule out other ocular disease. Anisometropic Amblyopia was diagnosed only after four weeks of spectacle wear. The selected patients were then advised occlusion therapy of 2-4 hours per day of better eye with stress on near visual task. Videogames, computers, mobile phone gaming and colouring in especially designed patterns were used as vision training aids. The outcome measure selected was best corrected visual acuity (BCVA) achieved that remained stable for three consecutive months of occlusion. Sixty one patients of anisometropic amblyopia were included in the study (32 males and 29 females) aged 12-30 years (mean age 17 years). Mean BCVA at the start of treatment was 20/125 (0.8 log MAR units) and 20/32 (0.2 log MAR units) at the end of the treatment. Thirty three patients (54%) out of 61 had BCVA of 20/20, while 58 patients (95%) had ≥ 20/40 BCVA, 01(1.6%) had 20/50 and 02 (3.27%) had 20/80 BCVA at the end of therapy. The results were statistically significant (p- value <0.0001) with a 95% confidence interval. This study clearly proves that there is no critical period for the treatment in older (12-30 years) anisometropic amblyope. Even 2-4 hours per day of occlusion of better eye with vision training thorough near visual task of amblyopic eye is effective. However, counseling and patient compliance is important for successful outcome of therapy.

Pupillary Reflex in Response to Light Stimulation Under Different Conditions in Healthy Individuals and Anisometropic Amblyopia Patients

Pupillary Reflex in Response to Light Stimulation Under Different Conditions in Healthy Individuals and Anisometropic Amblyopia Patients

Alterations induced by bangerter filters on the visual field: a frequency doubling technology and standard automated perimetry study.

Purpose. To investigate the effects of Bangerter filters on the visual field in healthy and in amblyopic patients. Materials and Methods. Fifteen normal adults and fifteen anisometropic amblyopia patients were analysed with standard automated perimetry (SAP) and frequency doubling technology (FDT) at baseline and with filters 0.8 and 0.1. Results. With 0.1 filter in SAP there was an increase of MD compared with controls (−10.24 ± 1.09 dB) in either the amblyopic (−11.34 ± 2.06 dB; P < 0.050) or sound eyes (−11.34 ± 1.66 dB; P < 0.030). With filters 0.8 the PSD was increased in the amblyopic eyes (2.09 ± 0.70 dB; P < 0.007) and in the sound eyes (1.92 ± 0.29 dB; P < 0.004) compared with controls. The FDT-PSD values in the control group were increased with the interposition of the filters compared to baseline (0.8; P < 0.0004 and 0.1; P < 0.0010). We did not find significant differences of the baseline PSD between amblyopic eyes (3.80 ± 2.21 dB) and the sound eyes (4.33 ± 1.31 dB) and when comparing the filters 0.8 (4.55 ± 1.50 versus 4.53 ± 1.76 dB) and 0.1 (4.66 ± 1.80 versus 5.10 ± 2.04 dB). Conclusions. The use of Bangerter filters leads to a reduction of the functionality of the magno- and parvocellular pathway.

Macular thickness in unilateral amblyopia as measured by optical coherence tomography: a meta analysis

To offer a clue for the etiology of amblyopia by systematically comparing the macular thickness measured by optical coherence tomography (OCT) between the amblyopic eye and the fellow normal eye in patients with unilateral amblyopia. Databases including Wanfang, PubMed and others were searched, and data were extracted after quality assessment, then the Meta analysis was performed by the RevMan 5.02 software. Four studies using the time-domain OCT (TD-OCT) were enrolled in the analysis and all those were anisometropic amblyopic patients. The only one study showed that the foveal minimum thickness is thicker in the amblyopic eyes than the fellow ones (P = 0.045). The meta analysis indicated the amblyopic eyes were 6.82 µm (P < 0.05, 95% CI: 2.81-10.83) thicker in the fovea (1 mm diameter region ). Five trials using the spectral-domain OCT (SD-OCT) were included in the analysis. It showed no significant difference in the foveal minimum thickness between amblyopic and fellow eyes. Also, no significant difference were detected in either anisometropic or strabismic subgroup (P = 0.50). Amblyopic eyes were 7.38 µm thicker in the fovea (1 mm diameter region) (P < 0.05, 95% CI: 3.13 -11.63) and significant difference in the anisometropic subgroup while no significant difference in the strabismic subgroup were detected. The macular fovea is thicker in the amblyopic eyes than the fellow ones by the use of OCT, so it is effective to measure the macular thickness of amblyopia in searching evidence for the etiology of amblyopia.

The Relationship between Higher-order Aberrations and Amblyopia Treatment in Hyperopic Anisometropic Amblyopia

PurposeTo investigate the relationship between higher-order aberrations (HOAs) and amblyopia treatment in children with hyperopic anisometropic amblyopia.MethodsThe medical records of hyperopic amblyopia patients with both spherical anisometropia of 1.00 diopter (D) or more and astigmatic anisometropia of less than 1.00 D were reviewed retrospectively. Based on the results of the amblyopia treatment, patients were divided into two groups: treatment successes and failures. Using the degree of spherical anisometropia, subjects were categorized into mild, moderate, or severe groups. Ocular, corneal, and internal HOAs were measured using a KR-1W aberrometer at the initial visit, and at 3-month, 6-month, and 12-month follow-ups.ResultsThe results of the 45 (21 males and 24 females) hyperopic anisometropic amblyopia patients who completed the 12-month follow-up examinations were analyzed. The mean patient age at the initial visit was 70.3 months. In total, 28 patients (62.2%) had successful amblyopia treatments and 17 patients (37.8%) failed treatment after 12 months. Among the patient population, 24 (53.3%) had mild hyperopic anisometropia and 21 (46.7%) had moderate hyperopic anisometropia. When comparing the two groups (i.e., the success and failure groups), ocular spherical aberrations and internal spherical aberrations in the amblyopic eyes were significantly higher in the failure group at every follow-up point. There were no significant differences in any of the HOAs between mild and moderate cases of hyperopic anisometropia at any follow-up. When the amblyopic and fellow eyes were compared between the groups there were no significant differences in any of the HOAs.ConclusionsHOAs, particularly ocular spherical aberrations and internal spherical aberrations, should be considered as reasons for failed amblyopia treatment.