Investigative ophthalmology & visual science
-
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.
-
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.
-
Invest. Ophthalmol. Vis. Sci. · Jan 2001
Investigation of the role of prolactin in the development and function of the lacrimal and harderian glands using genetically modified mice.
To determine whether prolactin receptor is essential for normal development and function of the lacrimal gland and whether hyperprolactinemia can alter lacrimal development. ⋯ Prolactin plays a small role in establishing the sexual dimorphism of male lacrimal glands. In females, hyperprolactinemia causes a hyperfemale morphology, suggesting a role in dry eye syndromes. Prolactin is required for porphyrin secretion by the Harderian gland but plays no essential role in the secretory immune function of the lacrimal gland.
-
Invest. Ophthalmol. Vis. Sci. · Sep 2000
Comparative StudyUltrasonographic evaluation of optic disc swelling: comparison with CSLO in idiopathic intracranial hypertension.
To determine the accuracy and reproducibility of ultrasonographic (US) readings of optic disc elevations in patients with papilledema compared with confocal scanning laser ophthalmoscope (CSLO) measurements. ⋯ The results indicate that US and CSLO readings are correlated i: both disc swelling and cupping conditions, but to a different extent because of a significant discrepancy in papilledema. US assessment can be considered highly reproducible. Combined US and HRT optic disc analysis may be recommended in papilledema evaluation as long as a better correlation can be demonstrated in further studies.
-
Invest. Ophthalmol. Vis. Sci. · Sep 2000
Post-treatment at 12 or 18 hours with 3-aminobenzamide ameliorates retinal ischemia-reperfusion damage.
The window of protection afforded by 3-aminobenzamide (3-ABA), a poly-(ADP-ribose) polymerase (PARP) inhibitor, against apoptotic loss of inner retinal elements after ischemia-reperfusion insult in rats was examined. ⋯ Administration of 3-ABA at 12 or 18 hours after ischemia, when there was accumulation of poly-(ADP-ribose) in the inner retina, significantly ameliorated retinal ischemia-reperfusion injury. These findings, together with earlier reports from our laboratory, are consistent with a late and pivotal role of PARP in apoptotic loss of inner retinal elements after ischemia-reperfusion insult to the retina.