Investigative ophthalmology & visual science
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To determine whether the Goldmann applanation tonometer can be modified to measure intraocular pressure (IOP) in the conscious rat. ⋯ The Goldmann applanation tonometer was modified to measure IOP in the conscious, unsedated rat. This instrument, the standard for measuring this key physiological parameter in the human eye, can now be applied to the laboratory rat. This may advance the use of this important animal as a model in IOP and glaucoma research.
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Invest. Ophthalmol. Vis. Sci. · Feb 2001
Rhodopsin-mediated blue-light damage to the rat retina: effect of photoreversal of bleaching.
Acute white-light damage to rods depends on the amount of rhodopsin available for bleaching during light exposure. Bleached rhodopsin is metabolically regenerated through the visual cycle involving the pigment epithelium, or photochemically by deep blue light through photoreversal of bleaching. Because photoreversal is faster than metabolic regeneration of rhodopsin by several orders of magnitude, the photon catch capacity of the retina is significantly augmented during blue-light illumination, which may explain the greater susceptibility of the retina to blue light than to green light. However, blue light can also affect function of several blue-light-absorbing enzymes that may lead to the induction of retinal damage. Therefore, this study was conducted to test whether rhodopsin and its bleaching intermediates play a role in blue-light-induced retinal degeneration. ⋯ Short time exposure to blue light has deleterious effects on retinal morphology. Because damage was observed only in the presence of the visual pigment, blue-light-induced retinal degeneration is rhodopsin mediated. Absorption of blue light by other proteins is not sufficient to induce light damage. Photoreversal of bleaching, which occurs only in blue but not in green light, increases the photon-catch capacity of the retina and may thus account for the difference in the damage potential between blue and green light.