A comprehensive approach to LASIK.

Candidates for LASIK procedures should have a stable refraction for at least 12 months. The three main contraindications for LASIK include patients with keratoconus or autoimmune disease and active corneal or ocular disease. The proper laser room environment is critical for optimal laser performance. The temperature should be maintained between 18 degrees C and 24 degrees C, and the humidity should be kept below 50%.

Does decompression diminish the discomfort of severe dysthyroid orbitopathy?

We assessed whether patients perceived that surgical decompression had reduced the discomfort of dysthyroid orbitopathy. Standard pain instruments were administered to 13 consecutive patients of a university-based oculoplastic practice who had undergone two-wall orbital decompression for dysthyroid optic neuropathy. We used visual analog scale (VAS) ratings of pre- and postoperative orbital discomfort. On a 0 to 10 scale, relief of discomfort after decompression was rated as moderate or better (VAS > 9.0) in 13 of 13 patients (mean VAS = 9.22, SD = 0.91) and complete (VAS = 10.0) in 8 of 13. Patients perceived that surgical decompression was associated with a clinically and statistically significant (p < 0.001) reduction of discomfort.

Relation of visual symptoms to topographic ablation zone decentration after excimer laser photorefractive keratectomy.

BACKGROUND: The authors used computer-assisted videokeratoscopy to analyze the relation of photorefractive keratectomy ablation zone decentration to subjective patient assessments of disturbing visual symptoms. METHODS: Ablation zone decentration was measured 1 month postoperatively. The study population was divided into two groups: group 1, patients whose ablation zone decentrations were less than 0.50 mm; group 2, patients whose ablation zone decentrations were greater than 0.50 mm. Visual symptoms including glare, rings or halos around lights and problems with night driving were scored preoperatively and 6 months postoperatively. The Hotelling T-square and chi-square tests were used. RESULTS: The mean decentration from the center of the ablation zone to the pupillary center was 0.30 mm and 190 degrees for group 1 compared with 0.66 mm and 198 degrees for group 2. The Hotelling T-square test showed a significant statistical preoperative/postoperative difference in group 1 (P < 0.03) for the halo symptom category. No other symptom category showed a significant statistical difference in either group for the mean scores. The Hotelling T-square test did not show a statistically significant difference between the two groups preoperatively to postoperatively regarding the mean scores of the individual patient differences for the three symptoms. The only significant statistical difference for the individual patient ratings preoperatively to postoperatively was for the halo symptom category (chi-square = 7.756; P < 0.03). CONCLUSIONS: Multivariate analysis did not show a significant statistical difference preoperatively between the two groups or postoperatively except for group 1 with regard to the halo symptom category. It appears from this study that ablation zone decentrations less than 0.89 mm from the pupillary center do not necessarily produce unwanted visual symptoms 6 months postoperatively.

Bilateral penetrating keratoplasty for sclerocornea in an infant with monosomy 21. Case report and review of the literature.

An 8-month-old caucasian girl with monosomy 21 and sclerocornea underwent bilateral penetrating keratoplasties. Both light and electron microscopic studies were performed on the corneal buttons. Light microscopy revealed variable and abnormal corneal thickness with the peripheral cornea being thinner than the center, lack of Bowman's layer, irregular stromal lamellae, stromal vascularization, markedly underdeveloped or absent Descemet's membrane, and marked attenuation of the endothelium. Electron microscopy demonstrated basal epithelial cells with a thin epithelial basement membrane residing directly on stromal lamellae without intervening Bowman's layer. Stromal collagen fibrils were irregular in size measuring 38-69 nm in diameter. We believe this to be the first report of corneal transplantation and the second reported case of sclerocornea in a patient with monosomy 21.

Sebaceous and meibomian carcinomas of the eyelid. Recognition, diagnosis, and management.

Sebaceous carcinoma of the eyelid is frequently misdiagnosed clinically and histopathologically. The tumor may present as a lid mass, recurrent chalazion, or diffuse unilateral blepharoconjunctivitis. Fifty percent of cases are misdiagnosed, often by an inexperienced general pathologist interpreting the initial biopsy. Frozen-section monitoring of surgical margins has been reported unreliable in 25% of cases. Mohs surgery is also unreliable in cases where there is pagetoid intraepithelial spread or skip lesions. This tumor may spread regionally into the lacrimal secretory and excretory systems, to regional lymph nodes, and rarely disseminate hematogenously. Guidelines for management are discussed.

Quipazine increases renin release by a peripheral hemodynamic mechanism.

Systemically administered serotonin (5-HT) agonists have been suggested to act centrally to increase plasma renin activity (PRA) and arterial pressure (AP). To test this hypothesis, hemodynamic responses were determined in conscious male rats after intracerebroventricular (i.c.v.) or intravenous (i.v.) administration of the direct 5-HT agonist quipazine. When administered i.v., quipazine increased AP and PRA, and decreased renal blood flow (RBF); doses of quipazine i.c.v. that increased AP to a similar degree failed to increase PRA. The increase in PRA elicited by i.v. quipazine was not blocked by propranolol, suggesting non-neural mechanisms. The increase in AP and decrease in RBF elicited by i.v. quipazine were not eliminated by prazosin, enalapril, or a V1-vasopressin antagonist administered alone or in combination. LY 53857, a 5-HT2 antagonist that enters the central nervous system (CNS), blocked all responses to i.v. quipazine. In contrast, the peripheral 5-HT2 antagonist xylamidine blocked the renin and RBF responses, but only attenuated the pressor response to quipazine. These data suggest that quipazine can act in the CNS to increase AP, but when administered systemically quipazine also activates vascular 5-HT2 receptors to increase AP further and to decrease RBF. The increase in PRA caused by i.v. quipazine is secondary to renal hemodynamics and is unrelated to CNS actions of this drug.

Field bioassay to evaluate contact and residual toxicities of insecticides to carabid beetles (Coleoptera: Carabidae).

A 2-yr field study evaluated the effects of selected insecticides on Bembidion obscurellum Motschulsky and Bembidion quadrimaculatum L., carabid predators of the wheat midge, Sitodiplosis mosellana (Géhin). A bioassay method using caged beetles indicated that insecticides differed significantly in their contact and residual toxicities when applied at maximum recommended field rates. Deltamethrin, the least toxic insecticide, caused approximately 30% mortality in both beetle species, but its residual toxicity on the soil remained constant for 1 wk. Dimethoate was initially more toxic (73% mortality) than deltamethrin but less toxic after 1 wk (12% mortality). Carbofuran and chlorpyrifos, the most toxic contact sprays, caused 83 to 100% mortality. After 1 wk, the residual toxicity of carbofuran had declined markedly (5% mortality) whereas the toxicity of chlorpyrifos remained high (82% mortality). Pitfall trapping was an inconclusive method of evaluating the toxicity of insecticidal sprays to carabid adults. In plots treated with carbofuran, pitfall catches of Bembidion species were not significantly different from those in control plots during a 6-wk period after spraying. In plots treated with chlorpyrifos, catches of Bembidion species were significantly lower than those in control plots 3-16 d after spraying, but not thereafter. Results suggested that adult immigration and residual toxicity influence pitfall catches and recovery of carabid populations after spraying.