Conjunctivitis.

Conjunctivitis refers to any inflammatory condition of the membrane that lines the eyelids and covers the exposed surface of the sclera. It is the most common cause of "red eye". The etiology can usually be determined by a careful history and an ocular examination, but culture is occasionally necessary to establish the diagnosis or to guide therapy. Conjunctivitis is commonly caused by bacteria and viruses. Neisseria infection should be suspected when severe, bilateral, purulent conjunctivitis is present in a sexually active adult or in a neonate three to five days postpartum. Conjunctivitis caused by Chlamydia trachomatis or Neisseria gonorrhoeae requires aggressive antibiotic therapy, but conjunctivitis due to other bacteria is usually self-limited. Chronic conjunctivitis is usually associated with blepharitis, recurrent styes or meibomianitis. Treatment requires good eyelid hygiene and the application of topical antibiotics as determined by culture. Allergic conjunctivitis is distinguished by severe itching and allergen exposure. This condition is generally treated with topical antihistamines, mast-cell stabilizers or anti-inflammatory agents.

Minocycline-induced scleral, dental, and dermal pigmentation.

PURPOSE: To report a case of scleral discoloration secondary to minocycline therapy. METHOD: Case report of a patient referred to a university-based cornea and external disease clinic. RESULTS: The patient had been treated with oral minocycline therapy for adult facial acne for 12 years when she began to develop bilateral blue-gray discoloration of the sclera as well as of the teeth, hard palate, ears, nail beds, and skin. CONCLUSIONS: Chronic systemic minocycline therapy may induce scleral pigmentary changes. The mechanism of discoloration and the long-term natural history upon cessation of minocycline are unclear.

Computerized videokeratography of keratoconus kindreds.

OBJECTIVE: To assess the role of heredity in the development of keratoconus. DESIGN: Prospective study. SETTING: Eye clinic providing secondary and tertiary ophthalmic care in Toronto. PATIENTS: Thirty-nine patients with keratoconus (57 eyes) and 48 relatives of 11 patients with keratoconus. The corneal topography of the family members was compared with that of a group of 68 volunteer control subjects (136 eyes) without clinical evidence or a family history of keratoconus. OUTCOME MEASURES: Three quantitative measures derived from computerized videokeratography: the relative steepness of the inferior cornea versus the superior cornea, central corneal power and the difference in central corneal power between the two eyes. All the data were statistically analysed with the use of nonparametric discriminant analysis. RESULTS: Fifteen family members who were believed to be clinically normal on the basis of refraction, keratometry and slit-lamp examination has statistically significant topographic abnormalities suggestive of early or mild keratoconus. CONCLUSIONS: The presence of these findings in family members of patients with keratoconus may represent the incomplete expression of a gene contributing to the development of the condition. Pedigree analysis suggested an autosomal dominant inheritance pattern in 9 of the 11 families. Our results underline the value of videokeratography for accurate family pedigree analysis and the diagnosis of keratoconus.

Ocular toxicity of mitomycin C and 5-fluorouracil in the rabbit.

We studied the histotoxic effects of mitomycin C and 5-fluorouracil (5-FU) in the eyes of New Zealand white rabbits using light microscopy. Twenty-four eyes of 24 rabbits received subconjunctival injections of mitomycin C (0.025, 0.05, 0.10, 0.20, 0.40 or 0.80 mg/mL) or 5-FU (10.0 mg/mL), either alone (0.25 mL) or in combination with anterior chamber injections (0.05 mL), once daily for 4 consecutive days. Two eyes of two rabbits received subconjunctival and anterior chamber injections of unpreserved sterile saline. The eyes were examined regularly for external signs of toxicity and were enucleated 4 weeks after the last injection. Mitomycin C produced considerable tissue damage in the anterior segment, the severity being related to both the concentration and the route of administration. Eyes that received both subconjunctival and anterior chamber injections showed more damage than those that received subconjunctival injections alone. At the highest concentration of mitomycin C the cornea was inflamed, with stromal necrosis and marked endothelial loss. Hemorrhagic iris necrosis was also seen. In contrast, the 5-FU-treated eyes showed no microscopic evidence of toxicity. We conclude that there is greater risk of toxic anterior segment effects when mitomycin C is used as adjunctive therapy following filtration or pterygium surgery.

Evaluation of corneal topography: past, present and future trends.

The keratometer and photokeratoscope have long been the standard instruments for measuring corneal curvature. The recent development of computer-assisted photokeratoscopy has greatly enhanced the evaluation of corneal topography, helping improve our understanding of both normal and abnormal topography and their influence on visual acuity. The authors review normal corneal topography and compare various tools, both new and old, currently available for evaluating corneal contour. Case studies are presented to illustrate some of the clinical and research applications of computer-assisted photokeratoscopy in an ophthalmology practice. Future applications of computer-assisted photokeratoscopy include intraoperative topography, the design of custom-fitted contact lenses and combination with ray-tracing analysis.