ANATOMICAL CORRELATES OF EXPERIMENTALLY-INDUCED MYOPIA

Purpose: The present study compares morphological changes associated w ith optical defocus-induced myopia (ODM) with those from form deprivat ion myopia (FDM), as it is yet to be determined whether the latter is a consequence of visual deprivation or active myopic eye growth. Metho ds: Hatchling chicks were reared for 2 weeks wearing a monocular trans lucent occluder or -10.00 D lens, with the other eye used as a control . After enucleation, eyes were processed for scanning electron microsc opy. Results: Anatomical profiles of control eyes revealed significant variations in tissue thickness as a function of nasotemporal location . Both FDM and ODM eyes demonstrated similar morphological profiles of retinal thinning, cartilaginous scleral thickening, enlarged photorec eptor inner segments and decreased photoreceptor cell density towards the ora serrata. A graded differential orientation of photoreceptors e xisted in all eyes. Conclusion: The comparable morphological changes i n FDM and ODM suggest that the response to altered visual experience i s similar in both paradigms.