A 1-week course of topical prednisolone acetate 1% four times daily did not affect the IOP-lowering effect of selective laser trabeculoplasty in eyes with primary open-angle glaucoma.
The performance deficit of glaucoma patients which may be minimal under normal testing conditions is magnified when external noise is added to the stimulus. VEPs and psychophysical thresholds show interesting differences in their sensitivity to this effect. Implications for the early detection of glaucoma are discussed.
The purpose of this study was to evaluate topical urea ophthalmic ointment as an agent to promote epithelial healing. Corneal epitheliopathy and epithelial defects were chemically induced in rabbits. Urea ophthalmic ointment was administered to one eye and control ointment to the fellow eye. The rabbits were examined by a masked observer for eleven days and points were awarded for steps of improvement in their ocular surface disease. The eyes receiving the urea ointment improved an average of 5.73 points while the control eyes improved 4.2 points (p < 0.0001). In conclusion, topical urea dissolved in a bland ointment encourages corneal reepithelialization and limits epithelial damage after toxic injury to corneal epithelium.
Ganciclovir nanoparticles were prepared using biodegradable polymers to evaluate a possible treatment for cytomegalovirus (CMV) retinitis. Bovine serum albumin (BSA), polyethylcyanoacrylate (PEC), and chitosan were utilized as drug carriers. The three products were evaluated for drug-loading capacity, particle size, and drug release. Spherical nanoparticles ranging between 0.3 and 1.2 pm in diameter were obtained, with those of PEC being the smallest. Loading capacity was in the range of 62566.9%. Drug release studies revealed decreasing release rates in the following order: BSA > PEC 2: chitosan. PEC nanoparticles containing ganciclovir (measured spectrophotometrically) and radioactive acyclovir (measured by liquid scintillation) showed essentially the same release patterns. The PEC nanoparticles containing [3H]acyclovir and ganciclovir together were selected for in vivo drug level studies. Following an intravitreal injection in rabbit eyes, drug levels in different eye tissues were used to compare the nanoparticle dispersion with free drug solution. The PEC nanoparticle product showed a markedly higher concentration than that of the drug solution over the 10 days, especially in the vitreous and retina. Therapeutic levels were detected for up to 10 days following administration of the nanospheres. Some lens opacification and vitreous turbidity were associated with administration of the PEC nanoparticles.
Several studies have indicated that contrast-dependent tasks, such as detecting threshold stimuli, may be more effective in discriminating glaucoma from normal groups if external noise is added to the stimulus. We sought to determine if the same were true for contrast-independent tasks. Subjects were 15 patients with glaucoma and a group of 20 normals with the same mean age. We employed two contrast-independent tasks, orientation defined texture and dot numerosity discrimination. The stimulus was presented on a computer controlled video monitor. One side of the display contained a standard and the other contained a non-standard target. For each task, noise was added by perturbing the main feature of the display, dot number or line orientation, by a Gaussian distribution truncated at 2 standard deviation units. There were four noise levels for each task. Subjects viewed the stimulus display and made a spatial two-alternative forced choice judgment. Subjects judged the side of the orientation texture which contained a sub-region with a different angle and the side of the dot figures which had the larger number of dots. Glaucoma patients performed more poorly than normals in discriminating the orientation texture ( p < 0:05) and in judging dot numerosity ( p < 0:05). This was true even in the absence of added external noise. Adding external noise did not increase the differences between glaucoma patients and normals. Unlike contrast-dependent tasks in which the differences between normal and glaucoma patients are increased when external noise is added, contrast-independent tasks show maximal differentiation between the two groups without added noise. Tasks such as texture discrimination and dot numerosity may be useful in detecting glaucoma.
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