Variance Analysis Of Visual Deficits In Different Amblyopic Children

Amblyopia is a common visual developmental disorder. It requires earlydiagnosis and treatment, or brings ill effects to the patients. The causes of amblyopiaare multiple. To analyze the variance of visual deficits in different amblyopes ishelpful to know the pathogenesis and make advices to the diagnosis and treatment.Mckee et al. analyzed the visual functions data in359adult amblyopes, and found thatthere were significant differences in the patterns of visual deficits among differentamblyopes. However, do these differences exist among different amblyopic children,what are the main factors that cause the differences, how to use these results to guidethe targeted treatment of amblyopia? These questions are worth of depth study.We developed three psychophysical detection methods by using PsychophysicsToolbox2.5package in Matlab, together with and other detection tools, six types ofvisual functions data from307subjects were collected at the Ophthalmology Centerof the Second Affiliated Hospital, Zhejiang University Medical School. To analyze thevariance of single visual function in different amblyopic children, we performedlinear fit on optotype acuity and other visual functions, then tested the differences offitting line parameters by permutation tests. To comprehensively compare the visualloss among different amblyopic children, we used Box-Cox transformation topreprocess the data, then extracted common factors from visual functions with factoranalysis and tested the differences of factor values in different patient categories withpermutation tests. To study the effects of stereoscopic deficit to the visual functions inamblyopic eyes, we divided all amblyopes into different age group, then tested thedifferences of optotype acuity, vernier acuity and edge contrast sensitivity betweenL800(stereoscopic acuity≤800") group and G800(stereoscopic acuity>800") groupin different ages with permutation tests, the results were helpful to explore the factorsthat cause the differences of visual deficits in different amblyopic children. Fromthese analysis, we made advices to the targeted treatment of amblyopia. The results of statistical analysis are as followed:1. The deficits of vernier acuity,grating acuity, edge contrast sensitivity in children with ametroic amblyopia aredifferent with other amblyopic children.2. The visual acuity (the combination ofvernier, grating and optotype acuity) and contrast sensitivity (the combination ofPelli-Robson and edge contrast sensitivity) in children with ametroic amblyopia aresignificantly better than those with anisometropic, strabismic and strab-anisometropicamblyopia, while the differences of visual performance in children with anisometropic,strabismic and strab-anisometropic amblyopa are not significant, which are disagreewith the study in adult amblyopia.3. There are significant effects of stereoscopicdeficits to the vernier acuity, optotype acuity and contrast sensitivity in amblyopiceyes, but the effects only appear after the maturation of corresponding visualfunctions.Based on these results, we believe that the differences of visual deficits amongdifferent amblyopes appear gradually during the development of visual system. Themain reason why there are no significant differences of visual deficits in children withanisometropic, strabismic and strab-anisometropic amblyopia is the late maturity ofvernier acuity and contrast sensitivity. Therefore, during the treatment of amblyopia,focused visual stimulation should be given to different amblyopic children before thematurity of each visual function, which can remedy the extra visual deficits in them.For example, vernier or grating task training should be strengthened in strabismicamblyopes, while contrast sensitivity training should be strengthened in anisometropicamblyopes.