New evidence on the state of stress of the san andreas fault system.

Contemporary in situ tectonic stress indicators along the San Andreas fault system in central California show northeast-directed horizontal compression that is nearly perpendicular to the strike of the fault. Such compression explains recent uplift of the Coast Ranges and the numerous active reverse faults and folds that trend nearly parallel to the San Andreas and that are otherwise unexplainable in terms of strike-slip deformation. Fault-normal crustal compression in central California is proposed to result from the extremely low shear strength of the San Andreas and the slightly convergent relative motion between the Pacific and North American plates. Preliminary in situ stress data from the Cajon Pass scientific drill hole (located 3.6 kilometers northeast of the San Andreas in southern California near San Bernardino, California) are also consistent with a weak fault, as they show no right-lateral shear stress at approximately 2-kilometer depth on planes parallel to the San Andreas fault.

Cataract extraction. Risk factors in a health maintenance organization population under 60 years of age.

Risk factors for cataract extraction in a young (less than 60 years of age) urban health maintenance organization population were evaluated in a case-control study. The subjects (72 case-control pairs) subscribed to the Kaiser Permanente Medical Care Program in the San Francisco Bay area and had cataract extraction between 1976 and 1980. All patients had visual acuity of at least 20/40 OU, documented before development of cataracts. Thirty-six (50%) of the 72 cataract extraction patients had at least one known risk factor for cataract formation, including trauma, intraocular inflammation, diabetes mellitus, syphilis, oral or topical steroid use, or previous eye surgery. Male patients were found to be a mean of 4.3 years younger than female patients, and diabetics were found to be a mean of 3.5 years older than nondiabetics. Variables found to be related to cataract extraction in univariate analysis included diagnosis of diabetes mellitus, a family history of cataracts, pulse rate, white blood cell count, and syphilis.

The value of routine dilated pupil screening examination.

We evaluated the cost-effectiveness of routine dilated fundus examination in improving visual outcomes. The cost of routine dilated fundus examination was related to the number of preventable cases of vision-threatening peripheral retinal disease. Patients with these diseases who had no risk factors were ascertained in a population of 1.75 million adults for a period of 6 months. Those whose last examination had been undilated were identified because only for them could routine dilated examination (RDE) have been substituted for undilated examination. The number of preventable cases was calculated for multiples of a 10% probability of prevention. The cost of RDE was determined from the number of undilated examinations in the same population and period and the cost of a single RDE. The number of patients who underwent undilated examination was estimated by random medical record review. The additional cost of a single RDE was determined from estimated examination times and payroll costs. Among patients without risk factors, 38 were identified for whom undilated examination rather than RDE had been performed. If prevention had been 10% effective, the substitution of 50,000 RDEs for undilated examinations costing the provider $433,000 would have been required per prevented case. These results suggest that most peripheral retinal diseases cannot be prevented by RDE. Routine dilated examination is an expensive test per prevented case. Published clinical guidelines lack evidence to recommend its use.

Metipranolol-associated granulomatous iritis.

PURPOSE: Topical metipranolol therapy for primary open-angle glaucoma has been associated with anterior granulomatous uveitis in the United Kingdom. We studied granulomatous uveitis reactions to topical metipranolol 0.3% therapy for primary open-angle glaucoma in two patients in the United States. METHODS: Two patients, aged 71 and 81 years, were given topical metipranolol 0.3% therapy for primary open-angle glaucoma. RESULTS: Both developed granulomatous uveitis. The iritis was associated with an increase in intraocular pressure in both patients and resolved on discontinuation of the drug. One patient was inadvertently rechallenged with metipranolol, and the iritis recurred. CONCLUSIONS: Topical metipranolol 0.3% therapy may be associated with the development of granulomatous uveitis and a paradoxical increase in intraocular pressure.

Reduction of cyclosporine dosage with ketoconazole in a patient with birdshot retinochoroidopathy.

PURPOSE: To report the successful reduction of cyclosporine dosage with adjunctive ketoconazole in a patient with birdshot retinochoriodopathy. METHOD: Case report. RESULTS: A 55-year-old woman treated with cyclosporine for birdshot retinochoroidopathy had ketoconazole (200 mg/day) added to her medical regimen. Her cyclosporine dosage was reduced to 40 mg per day from 200 mg per day, an 80% reduction. No toxic effect was observed during 12 months of follow-up nor was there progression of the birdshot retinochoroidopathy. CONCLUSIONS: Cyclosporine dosage may be reduced considerably in patients with uveitis who use adjunctive ketoconazole. The regimen appears to be safe and efficacious.

Cytomegalovirus-associated acute retinal necrosis syndrome.

PURPOSE: To describe a case of acute retinal necrosis syndrome in which a polymerase chain reaction-based assay provided evidence for cytomegalovirus as the causative agent of the syndrome. METHODS: Polymerase chain reaction-based assays were used to analyze a vitreous aspirate from a 70-year-old man with acute retinal necrosis syndrome. The specimen was tested for cytomegalovirus, varicella-zoster virus, and herpes simplex virus type 1 and type 2. RESULTS: The polymerase chain reaction assay for cytomegalovirus was positive, and polymerase chain reaction assays for varicella-zoster virus and herpes simplex virus type 1 and type 2 were negative. CONCLUSION: Cytomegalovirus may be a causative agent of acute retinal necrosis syndrome.

Microsporidial keratoconjunctivitis in a patient without human immunodeficiency virus infection.

PURPOSE: To describe a case of microsporidial keratoconjunctivitis in a patient without human immunodeficiency virus (HIV) infection. METHODS: Case report. An epithelial corneal scraping from a woman with chronic bilateral keratoconjunctivitis was evaluated by Giemsa stain. RESULTS: Giemsa stain of an epithelial corneal scraping disclosed intracellular and extracellular spores characteristic of microsporidia. An HIV enzyme-linked immunosorbent assay (ELISA) test was negative. The signs and symptoms of the bilateral keratoconjunctivitis resolved after treatment with albendazole. CONCLUSION: Microsporidia may cause a chronic epithelial keratoconjunctivitis in the absence of HIV infection.

Fuchs' superficial marginal keratitis.

We studied three cases of Fuchs' superficial marginal keratitis, an uncommon condition that is characterized by intermittent, recurrent episodes of ocular irritation accompanied by marginal infiltrates and that is followed by progressive marginal superficial stromal thinning. Usually, it has an indolent course with spontaneous remission, and good visual acuity is preserved. In advanced cases, a pseudopterygium develops in the area of marginal thinning. The pseudopterygium encroaches onto the cornea over a period of years, but spares the central cornea. In two of our three cases, the degree of thinning beneath the pseudopterygium became marked. This led to corneal perforation during pseudopterygium excision in one case, and after blunt trauma in the other. These complications indicate the need for special precautions when caring for these patients.

Vitreitis and Waldenström's macroglobulinemia.

PURPOSE: To describe vitreitis in a patient with Waldenström's macroglobulinemia. METHODS: Case report and review of pertinent literature. RESULTS: A 90-year-old man developed vitreitis 10 years after a systemic diagnosis of a lymphoproliferative disorder. Numerous small, normal-appearing lymphocytes were seen on pathologic examination of the vitreous. He developed worsening lymphadenopathy and was diagnosed with Waldenström's macroglobulinemia after systemic review. CONCLUSION: Chronic lymphoproliferative diseases such as Waldenstrom's macroglobulinemia may cause vitreitis.

Supratarsal injection of corticosteroid in the treatment of refractory vernal keratoconjunctivitis.

PURPOSE: We studied supratarsal injection of corticosteroid as a new therapeutic modality for treating severe vernal keratoconjunctivitis to determine its efficacy in treating patients refractory to all conventional therapy. METHODS: Twelve patients with vernal keratoconjunctivitis resistant to all established therapy were prospectively studied by randomly assigning them to receive supratarsal injection of either short- or intermediate-acting corticosteroid. Relief of symptoms and resolution of clinical signs were evaluated. Patients were followed up to four years to identify side effects. RESULTS: All patients experienced dramatic symptomatic relief within one to five days, regardless of the type of corticosteroid injected. Marked decrease in cobblestone papillae was noted in 14.9 days (mean) after short-acting corticosteroid injection and 12.8 days after intermediate-acting corticosteroid injection (P = .65). Shield ulcers and limbal involvement resolved in one to three weeks, independent of the corticosteroid used (P = .90). No complications were observed with supratarsal injection of short-acting corticosteroid. One patient developed persistent increase of intraocular pressure after injection of intermediate-acting corticosteroid. CONCLUSIONS: The dramatic symptomatic and clinical improvement suggests that supratarsal injection of corticosteroid may be a valuable therapeutic approach to treating refractory vernal keratoconjunctivitis. Short-acting and intermediate-acting corticosteroids were equally efficacious. Because of the lack of intraocular pressure increase observed with short-acting corticosteroid, we favor its use in supratarsal injection.