Purchase this article with an account.
J.J. Sloper, M.M. Neveu, N.K. Ragge, L.C. Burton, J.R. O. Collin, G.E. Holder; Midline Interactions Are Not Critical for the Development of the Human Optic Chiasm: Major Differences Between Man and Mouse . Invest. Ophthalmol. Vis. Sci. 2006;47(13):802.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Rodent retinofugal fibres from each eye interact at the chiasmal midline to determine their hemispheric projection. Monocular enucleation early in development results in an albino–like misrouting of the remaining hemispheric projections. The present study addresses the question of whether similar changes occur in the human.
Fourteen subjects with unilateral anophthalmia or very severe microphthalmos aged 1 month to 61 years underwent clinical and electrophysiological examination. Ten age–matched albino and ten normal subjects served as control groups. Full–field ERGs were recorded from the remaining eye of the unilaterally anophthalmic/severely microphthalmic subjects. Five channel VEPs were recorded in all subjects to flash (FVEP) and pattern appearance (PVEP) stimulation. Component amplitude and latency were analysed. Abnormality was defined as an inter–hemispheric difference of more than 6ms in latency or 50% in amplitude.
Full–field ERGs in the remaining eye of all the anophthalmic or severely microphthalmic subjects were normal. FVEPs and PVEPs from all anophthalmic or severely microphthalmic subjects did not significantly differ from normal in latency, amplitude or hemisphere distribution (P>0.5). FVEPs and PVEPs in albino subjects demonstrated significant inter–hemispheric asymmetries of both amplitude and latency (P<0.0001) that were significantly different from normal (P<0.0001).
Normal segregation of the hemispheric projections at the optic chiasm does not require binocular fibre interaction at the chiasmal midline in man, unlike in rodents. The data emphasize the potential hazards in extrapolating from lower animals to man.
This PDF is available to Subscribers Only