Search PubMed⌕ Search

Biomedical subjects

O D Schein

Publications and source records attributed to O D Schein.

At least 91 records · Page 5Linked to original sources
PubMed1994

Primary graft failure: a case control investigation of a purported cluster.

Primary graft failure is a rare but major complication of penetrating keratoplasty. An apparent clustering of four cases during a 1-month period led to a review of all 778 keratoplasties performed by nine surgeons at Massachusetts Eye and Ear Infirmary from July 1, 1986 to June 30, 1988. The objectives of this study were (a) to investigate the possibility that cases of primary graft failure occurred in clusters within their physical environment of space, time, and personnel and (b) to determine the frequency of and evaluate possible risk factors for primary graft failure. Twenty-one cases of primary graft failure were found, resulting in an incidence rate of 2.7% during this period. A 13.3% incidence of primary graft failure was found in donor mates, suggesting improper tissue preparation. The charts and eye bank records of the 21 cases and 84 age-matched controls, randomly selected from the group of all keratoplasties, were reviewed for donor-, recipient-, surgeon-, and surgery-related characteristics. Improper tissue preparation was not associated with primary graft failure. An individual surgeon was the most significant risk factor [odds ratio = 6 (95% CI: 2.1-17.0)].

Adult↗
PubMed1994

Cortical lenticular opacification: distribution and location in a longitudinal study.

PURPOSE: To examine the distribution of cortical opacification of the lens by lens quadrant in a longitudinal study. METHODS: In 1990, a follow-up assessment of a cohort of Chesapeake Bay watermen, initially studied in 1985, was performed. Four hundred thirty-seven subjects (834 eyes) had gradable cortical photographs for at least one eye in both 1985 and 1990. Cortical photographs were graded by both estimating total area and determining the quadrant with the greatest degree of cortical opacification. RESULTS: The prevalence and severity of cortical opacification increased with age with a high degree of concordance (84%) between eyes. For the 47 eyes with cortical opacification > or = 1/8 at baseline, the principal locations of opacification were: inferonasal 63.8%, inferotemporal 17.0%, superonasal 6.4%, and superotemporal 12.8% (P < 0.001, compared with equal distribution by quadrant). Five-year development of new cortical opacification and five-year progression of existing cortical opacification showed even greater preferential occurrence in the inferonasal quadrant of the lens. CONCLUSIONS: In this population, the inferonasal quadrant of the lens is the principal site of cortical opacification in both cross-sectional and longitudinal assessment. This finding is consistent with the hypothesis that sunlight exposure is a significant risk factor for cortical opacification.

Adult↗
PubMed1993

Anterior corneal disease of epidermolysis bullosa simplex.

We report the histopathological findings of the anterior cornea from a patient with skin biopsy-proven epidermolysis bullosa simplex. As seen with light microscopy, the cornea had a fibrocellular pannus deep to a thickened epithelial basement membrane. Transmission electron microscopy of the anterior cornea demonstrated a nonhomogeneous basal epithelial layer with abnormal attachment complexes to an irregular, multilaminar basement membrane. The findings of transmission electron microscopy of the bulbar conjunctiva were normal.

Adult↗
PubMed1993

Contact lens abrasions and the nonophthalmologist.

Corneal abrasions associated with contact lens wear are commonly evaluated and treated in acute care clinics and emergency departments by nonophthalmologists. The risk of progression to suppurative keratitis in this setting requires management distinct from that of other mechanical (eg, fingernail scratch) corneal abrasions. The antibiotic chosen should reflect the need for prophylaxis against Pseudomonas. Conditions favoring bacterial growth, specifically occlusive patching and/or use of steroid containing compounds, should be avoided, and 24-hour follow-up examination is recommended.

Adult↗
PubMed1993

Efficacy of a disinfectant wipe method for the removal of adenovirus 8 from tonometer tips.

PURPOSE: To determine the efficacy of a disinfectant wipe method in eliminating adenovirus 8 from both Goldmann tonometer and pneumotonometer tips, and to determine the efficacy of 5-minute disinfectant soaks in removing the virus from Goldmann tonometer tips. METHOD: Quantification of adenovirus 8 in the ocular secretions of six infected patients was performed. Clinically relevant inocula of adenovirus 8 were then prepared in a serum suspension which was used to contaminate Goldmann tonometer and pneumotonometer tips. Each contaminated tip was subjected to either a dry wipe or a wipe with one of the following: water, isopropyl alcohol, hydrogen peroxide, and iodophor. The tips were than quantitatively assayed for residual adenovirus 8. Disinfectant soaks were similarly assessed using contaminated Goldmann tonometer tips soaked in water, hydrogen peroxide, iodophor, and sodium hypochlorite. RESULTS: Adenovirus 8 was recovered from both types of tonometer tips after dry wipes, but no viable virus was recovered from tips wiped with water only or with any of the disinfectants tested. Adenovirus 8 also was recovered from Goldmann tonometer tips that were either rinsed or soaked in water; no virus was recovered from tips soaked for 5 minutes in any of the disinfectants tested. CONCLUSION: A disinfectant wipe method using isopropyl alcohol, hydrogen peroxide, or iodophor is effective in removing adenovirus 8 from both Goldmann tonometer and pneumotonometer tips. Five-minute disinfectant soaks also are effective for Goldmann tonometer tips.

Adenovirus Infections, Human↗
PubMed1993

A randomized trial of intraocular lens fixation techniques with penetrating keratoplasty.

PURPOSE: Pseudophakic corneal edema is the principal indication for penetrating keratoplasty in the United States. Currently, three techniques of intraocular lens (IOL) fixation during penetrating keratoplasty for this condition are commonly used--flexible anterior chamber IOL (AC IOL) implantation, iris suture fixation of a posterior chamber IOL (PC IOL), and transscleral suture fixation of a PC IOL. This study represents the first prospective, randomized comparison of these three techniques. METHODS: One hundred seventy-six consecutive patients with pseudophakic corneal edema who underwent penetrating keratoplasty with IOL exchange were randomized to one of the three implantation techniques. Standardized evaluations were performed at baseline and at 6, 12, and 18 months postoperatively. Life-table analysis provided cumulative risk estimates for specific complications. RESULTS: Randomization produced comparable groups at baseline. The cumulative risk of macular edema was significantly less for the iris fixation cohort than for either the AC IOL or scleral fixation group. A complications index was constructed based on the major adverse outcomes of glaucoma escalation, cystoid macular edema, IOL dislocation, and graft failure. A significantly lower risk of complication was found for iris compared with scleral fixation of PC IOLs. CONCLUSION: The authors conclude that transscleral fixation of the PC IOL at the time of penetrating keratoplasty for pseudophakic corneal edema is associated with a greater risk of adverse outcome than iris fixation of a PC IOL.

Aged↗
PubMed1992

Microbial contamination of in-use ocular medications.

Two hundred twenty in-use medications from 101 patients with nonmicrobial ocular surface disease were studied by culturing the bottle caps, a drop produced by simple inversion, and the interior contents removed sterilely. Conjunctival cultures were taken from these patients and 50 age-matched controls. Pathogenic organisms were harvested from conjunctivae significantly more frequently (P less than .01) from cases (34 of 101) than from controls (five of 50). Sixty-four medications (29%) had microorganisms cultured from at least one medication site. Gram-negative organisms were significantly more likely (P less than .00001) to be isolated from all medication sites than gram-positive organisms. Additionally, when isolated from medication sites, the gram-negative organisms were highly likely to be cultured from the conjunctiva as well. This was not true for pathogenic gram-positive organisms. We conclude that a cycle of contamination between in-use medications and conjunctivae may represent an important risk factor for microbial keratitis in patients with ocular surface disease.

Conjunctiva↗
PubMed1992

The increased risk of ulcerative keratitis among disposable soft contact lens users.

Previous controlled studies on contact lens-associated ulcerative keratitis were performed before the widespread use of disposable contact lenses. Therefore, a controlled study was undertaken to determine the relative risk of ulcerative keratitis among users of disposable soft contact lenses compared with the risk among users of other lens types. Forty-six consecutive cases of contact lens-associated ulcerative keratitis were identified between January 1990 and June 1992 at a corneal specialty practice in western Michigan. Five controls, matched to each case patient according to the dispensing data and prescribing practitioner, were obtained for 42 cases (91%). Users of daily-wear rigid gas-permeable lenses had the lowest risk of developing ulcerative keratitis. Relative to users of daily-wear soft contact lenses, users of extended-wear soft contact lens had an age-adjusted and sex-adjusted relative risk of 1.87 (95% confidence interval, 0.61 to 5.71). Disposable soft contact lens users had the highest risk of developing ulcerative keratitis, with an adjusted relative risk of 14.16 (95% confidence interval, 5.47 to 37.63) compared with daily-wear soft contact lens users and 7.66 (95% confidence interval, 2.27 to 25.83) compared with conventional extended-wear soft contact lens users.

Acanthamoeba Keratitis↗
PubMed1992

Phototoxicity and the cornea.

The cornea is sensitive to the effects of ultraviolet (UV) light and can suffer both acute and chronic toxicity. Ultraviolet keratitis is associated with relatively short exposures to light sources such as welding arcs or tanning lamps. The corneal effects are seen within a few hours following exposure and typically will resolve within 72 hours. Chronic exposure to environmental UV light may lead to a variety of ocular surface abnormalities that rarely resolve in the absence of therapy. Ultraviolet light, while potentially destructive, also can be used therapeutically. Recently, the photoablative properties of the excimer laser have been used in corneal refractive surgery. This laser uses UV light to break chemical bonds and remove tissue. Corneal phototoxicity is a reflection of the sensitivity of the ocular surface to photochemical injury. Fortunately, effective protection in the form of UV-blocking lenses is widely available.

Adult↗
PubMed1991

The incidence of ulcerative keratitis among aphakic contact lens wearers in New England.

We conducted a population-based incidence study in five New England states to quantify the risk of ulcerative keratitis associated with contact lens use among aphakic persons. All practicing ophthalmologists in the five-state area were surveyed to identify prospectively all new cases of ulcerative keratitis during a 4-month period. The number of aphakic persons using specific types of contact lenses was estimated through a telephone survey of 4178 households identified by random digit dialing. The annualized incidence of ulcerative keratitis among aphakic persons using contact lenses was estimated to be 52 cases per 10,000 aphakic contact lens wearers (95% confidence interval (CI), 31.1 to 86.9). The risk of ulcerative keratitis varied substantially by lens use, with extended wear having an estimated sevenfold greater risk relative to daily wear (95% CI, 1.6 to 30.2). Rates of ulcerative keratitis in aphakic persons using contact lenses were much greater than rates among cosmetic wearers of the same lens type: for daily-wear lenses, aphakic persons were estimated to have 6.3 times the risk of cosmetic wearers (95% CI, 1.9 to 21.0), and for extended-wear lenses, aphakic persons were estimated to have 8.7 times the risk of cosmetic wearers (95% CI, 3.5 to 21.9). These risks are useful in assessing the benefits and risks of contact lens wear as an alternative to other methods of aphakic correction.

Adolescent↗
PubMed1990

A gas-permeable scleral contact lens for visual rehabilitation.

We evaluated the use of a highly gas-permeable, fluid-filled scleral lens for patients with diseased corneas for whom conventional contact lens strategies failed. Fifteen patients were successfully fit with individually fabricated scleral lenses. Significant corneal hypoxia, which limited the use of previous polymethylmethacrylate scleral lenses, was not encountered. Preliminary results suggest that a gas-permeable scleral lens may offer therapeutic as well as visual benefit to some patients with severe corneal disease.

Adult↗
PubMed1990

Ulcerative keratitis in contact lens wearers. Incidence and risk factors.

A case-control study of ulcerative keratitis in soft contact lens (CL) users compared three groups of daily wear or extended wear patients: (a) 86 patients with ulcerative keratitis, (b) 61 hospital-based controls, and (c) 410 population-based controls. Overnight lens use, whether regularly with extended wear lenses or occasionally with daily wear lenses, emerged as the preeminent risk factor for ulcerative keratitis. It increased risk by 10 to 15 times in users of extended wear lenses and by 9 times in users of daily wear lenses when these groups were compared with subjects engaged in strict daily wear of daily wear lenses. Even when actual overnight wear was not taken into account, the relative risk was four times greater in users of extended wear lenses than in users of daily wear lenses. The study found a marginal association (p = 0.056) between lens care frequency in general and ulcerative keratitis in comparing ulcerative keratitis cases with population controls. Of the individual hygiene-related measures, evidence of a protective effect was strongest for cleaning the lens case. Smokers showed a threefold greater risk than nonsmokers, regardless of the type of lens worn. An incidence study found the rate of ulcerative keratitis to be approximately 1 in 2,500 daily wear lens users and 1 in 500 extended wear lens users per year. This finding was statistically consistent with the risk ratio noted in the case-control study. Extrapolations suggest that 4,000 of the 9 million U.S. users of daily wear soft lenses develop ulcerative keratitis annually. Among the 4 million U.S. extended wear soft lens users, 8,000 may do so per year.

Adult↗
PubMed1989

The relative risk of ulcerative keratitis among users of daily-wear and extended-wear soft contact lenses. A case-control study. Microbial Keratitis Study Group.

Over 13 million people in the United States wear soft contact lenses for refractive correction. Ulcerative keratitis is considered the most serious adverse effect of the use of contact lenses. We performed a case-control study with 86 cases patients, estimating separately for hospital-based (n = 61) and population-based (n = 410) controls the relative risk of ulcerative keratitis among users of extended-wear as compared with daily-wear soft contact lenses. The relative risk of ulcerative keratitis for extended-wear as compared with daily-wear lenses among the population-based controls was 3.90 (95 percent confidence interval, 2.35 to 6.48) and among the hospital-based controls, 4.21 (95 percent confidence interval, 1.95 to 9.08). Thirty-eight percent of those with extended-wear lenses used them only during the day, and 11 percent of those with daily-wear lenses occasionally wore them overnight. When lens wearers were distinguished according to their overnight use of lenses, the users of extended-wear lenses who wore them overnight had a risk 10 to 15 times as great as the users of daily-wear lenses who did not, and the users of daily-wear lenses who sometimes wore them overnight had 9 times the risk of the users of such lenses who did not. For the users of extended-wear lenses, the risk of ulcerative keratitis was incrementally related to the extent of overnight wear. A reduction in risk associated with more frequent attention to lens hygiene was almost significant. We conclude that soft contact lenses worn overnight carry a significantly greater risk for ulcerative keratitis than soft lenses worn only during the day.

Contact Lenses, Extended-Wear↗
PubMed1989

The incidence of ulcerative keratitis among users of daily-wear and extended-wear soft contact lenses.

The wearing of contact lenses has increased dramatically in the past decade; over 4 million people in the United States now use extended-wear soft contact lenses, and 9 million use daily-wear soft contact lenses. Numerous reports have caused concern that the use of soft contact lenses, especially extended-wear lenses, may result in a substantial risk of ulcerative keratitis. To examine this issue, we conducted a prospective study in five New England states to estimate the incidence of ulcerative keratitis among those who use cosmetic extended-wear and daily-wear soft contact lenses. To obtain the numerator for each estimate of incidence, we surveyed all practicing ophthalmologists in the study area to identify all new cases diagnosed over a four-month period. To provide the denominator, we conducted a survey of 4178 households to estimate the number of persons who wore each type of soft contact lens. The annualized incidence of ulcerative keratitis was estimated to be 20.9 per 10,000 persons using extended-wear soft contact lenses for cosmetic purposes and 4.1 per 10,000 persons using daily-wear soft contact lenses for cosmetic purposes (P less than 0.00001).

Adolescent↗