Anatomical correlates of experimentally induced myopia.
OBJECTIVE
The present study compares morphological changes associated with optical defocus-induced myopia (ODM) with those from form deprivation myopia (FDM), as it is yet to be determined whether the latter is a consequence of visual deprivation or active myopic eye growth.


METHODS
Hatchling chicks were reared for 2 weeks wearing a monocular translucent occluder or -10.00 D lens, with the other eye used as a control. After enucleation, eyes were processed for scanning electron microscopy.


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 photoreceptor inner segments and decreased photoreceptor cell density towards the ora serrata. A graded differential orientation of photoreceptors existed in all eyes.


CONCLUSIONS
The comparable morphological changes in FDM and ODM suggest that the response to altered visual experience is similar in both paradigms.
School of Optometry, University of New South Wales, Sydney, Australia. J.Beresford@UNSW.EDU.AU
J A
JA
Beresford
S G
SG
Crewther
D P
DP
Crewther
D000818:Animals; D002645:Chickens; D008027:Light; D008855:Microscopy, Electron, Scanning; D009216:Myopia / Q000209:etiology / Q000473:pathology*; D010786:Photoreceptor Cells / Q000648:ultrastructure; D012160:Retina / Q000473:pathology*; D012683:Sensory Deprivation