Faculty Bibliography

PURPOSE: The authors reviewed their experience with total conjunctival flaps (TCF) and partial conjunctival flaps (PCF) for the past 5 years in 61 patients. METHODS: Forty-eight patients had TCF and 13 had PCF. Diagnoses for surgery included severe bullous keratopathy for chronic graft failure (not candidates for keratoplasty) (19), herpes zoster ophthalmicus (7), chronic ulcerative keratitis (14), neurotrophic keratitis (2), and herpes simplex keratitis (9). RESULTS: There were seven complications. Four flap retractions occurred in the TCF group, requiring resuturing in two. Three complications occurred in the PCF group. One patient had two flap retractions and recurrent ulceration, requiring tarsorrhaphy. One patient with PCF suffered a perforation after flap retraction, necessitating penetrating keratoplasty. CONCLUSION: The authors believe conjunctival flaps are underused and should be considered seriously for bullous keratopathy, neurotrophic keratitis, recalcitrant keratitis, and persistent nonhealing epithelial defects

Nitrates have been a major part of the internist's pharmacopoeia for more than 100 years, predominantly for the relief of anginal symptoms. The effects of nitroglycerin on the eye and specifically on intraocular pressure has been investigated with diverse results. However, nitroglycerin may also serve to protect retinal ganglion cells against glutamate mediated toxicity--a form of cell death that may be critical in glaucomatous blindness. Consequently, we therefore sought to evaluate whether nitroglycerin preparations, taken for non-ophthalmic reasons, had an effect on glaucomatous damage

BACKGROUND: S(+) ketamine, because of its higher anesthetic potency and lower risk of psychotomimetic reactions, has been suggested to be superior to presently available racemic ketamine. The racemate is a direct vasodilator in vivo, and thus the authors investigated the vasorelaxing effects of ketamine enantiomers on rat aorta. METHODS: Rat isolated aortic rings with and without endothelium were contracted with 3 x 10(-7) M norepinephrine. Then 10(-5) to 3 x 10(-3) M S(+), R(-), or racemic ketamine were added cumulatively. Vascular responses to ketamine were further studied in rings pretreated with the nitric oxide synthase inhibitor N(omega)-nitro-L-arginine (NNLA), the adenosine triphosphate-sensitive K+ channel antagonist glibenclamide, and the L-type calcium channel blocking agent D888. RESULTS: Ketamine enantiomers and the racemate produced concentration-dependent vasorelaxation. The relaxing effect of S(+) ketamine was significantly weaker compared with R(-) ketamine and the racemate reflected by the half-maximum effective concentration (EC50) values of 11.6 x 10(-4), 4.8 x 10(-4), and 6 x 10(-4) M, respectively. Removal of the endothelium and NNLA or glibenclamide pretreatment did not significantly alter the vasorelaxing effect of ketamine. In contrast, D888 pretreatment significantly shifted the concentration-effect curves of both S(+) and R(-) ketamine rightward (EC50 values of 18.9 x 10(-4) and 8.5 x 10(-4) M, respectively), whereas the difference between the isomers was not affected. CONCLUSIONS: Vasorelaxation by ketamine enantiomers is quantitatively stereoselective: The effect of S(+)ketamine is significantly weaker compared with that of the racemate and R(-) ketamine. This stereoselective difference is not due to nitric oxide release, activation of adenosine triphosphate-sensitive potassium channels, or differential inhibition of L-type calcium channels

PURPOSE: To compare postoperative intraocular pressure (IOP) after administration of acetazolamide and timolol following phacoemulsification and intraocular lens implantation. SETTING: Ophthalmic Consultants of Long Island, Rockville Centre, New York, USA. METHODS: Sixty patients were included in a prospective, randomized, masked trial. The patients received either two doses of oral, sustained-release acetazolamide (Diamox Sequels) or a single dose of topical timolol 0.5% gel (Timoptic XE). Intraocular pressure was measured by Goldmann applanation tonometry preoperatively and 1 day postoperatively. RESULTS: Mean preoperative IOP was 16.4 mm Hg. One day postoperatively, it was 19.5 mm Hg in the oral acetazolamide group and 15.9 mm Hg in the timolol gel group. One patient in the acetazolamide group developed significant adverse reactions. CONCLUSION: Prophylactic use of topical timolol 0.5% gel for viscoelastic-induced ocular hypertension after cataract extraction appears to offer better IOP control than oral acetazolamide and has potentially fewer adverse systemic effects

PURPOSE: To evaluate the effect of substituting topical cyclosporin A 0.5% for topical corticosteroids in patients with postkeratoplasty glaucoma. METHODS: Topical cyclosporin A 0.5% was prospectively substituted for topical corticosteroids to treat 25 patients with postkeratoplasty glaucoma. RESULTS: Twenty-one (84%) of 25 patients showed a reduction in intraocular pressure (IOP) (range, 1-22 mm Hg; mean, 8.7 mm Hg). Follow-up ranged from 3 to 12 months (mean, 5.8). Graft clarity was maintained in all patients, with one allograft rejection episode. Thirteen patients were able to discontinue one or more glaucoma medication(s). CONCLUSION: Topical cyclosporin A 0.5% may be substituted for topical corticosteroids to aid in the management of postkeratoplasty patients with glaucoma. However, the resultant decrease in IOP may be associated with an increased risk for immune rejections

PURPOSE: To evaluate the effect of photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) on corneal sensation. SETTING: Eye Institute, Medical School of the University of Crete, Heraklion, Greece, and Orasis, Hellenic Eye Center of Athens, Greece. METHODS: In a masked study, corneal sensation was measured with the Cochet-Bonnet aesthesiometer in 40 consecutive patients 6 to 12 months following PRK and LASIK (60 mm constitutes normal reading and < 40 mm, abnormal). RESULTS: After 6 to 12 months, the mean corneal sensation following PRK was 39.2 mm (range 30 to 55 mm) (mean 9.5 months) and after LASIK, 53.6 mm (range 40 to 60 mm) (mean 9.3 months). The mean correction attempted for PRK was 7.05 diopters (D) (range 2.5 to 12.0 D) and for LASIK, 11.71 D (range 6.0 to 20.0 D). CONCLUSION: In this group of patients, with correction of primarily severe myopia, corneal sensation was significantly greater after LASIK than after PRK

PURPOSE: Viscoelastic-induced ocular hypertension following penetrating keratoplasty (PK) may result in endothelial cell loss and optic nerve damage. METHODS: In a prospective, randomized, masked trial, two doses of oral sustained-release acetazolamide were compared to a single dose of topical 0.5% timolol gel after 40 PKs. RESULTS: The mean preoperative intraocular pressure (IOP) was 17.4 mm Hg for the oral acetazolamide group and 16.7 mm Hg for the timolol gel group. The mean IOP on the first postoperative day was 17.9 mm Hg with oral acetazolamide and 12.9 mm Hg with timolol gel. One patient developed significant adverse reactions with oral acetazolamide; there were no adverse reactions with timolol gel. CONCLUSION: Prophylactic use of timolol gel for viscoelastic-induced ocular hypertension after PK appears to offer better IOP control than oral acetazolamide, with potentially fewer adverse systemic effects