Diurnal and circadian variations in intraocular pressure in goats exposed to different lighting conditions.

The effect of constant light and constant darkness on intraocular pressure (IOP) in goats has not been investigated. We hypothesized that IOP variations would differ between goats kept under a cycle of 12 hours of light and 12 hours of darkness (LD), constant darkness (DD), and constant light (LL). To test this hypothesis, goats were exposed to these conditions for five days (LD, 30 goats; DD, 10 goats; LL, 10 goats).