Objective: Our goal was to determine the effect of endoscopic white li
ght on the developing mammalian retina by quantitative histological an
alysis. Study Design: Albino rats at postnatal days 10 (n = 16) and 16
(n = 20) were exposed to endoscopic white light for 1 h, while an equ
al number oflittermate controls were not exposed, but otherwise treate
d identically. The thickness of the outer nuclear layer (ONL) and the
total retinal thickness were measured light microscopically using a co
mputer-assisted morphometry program. Results: We found no statisticall
y significant decrease in the thickness of the ONL or the total retina
l thickness, nor were any significant decreases found in the ONL or th
e total retinal thickness for male or female groups. Conclusion: Endos
copic white light does not cause damage to the developing rodent neura
l retina detectable at the light microscopic level.