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Biomedical subjects

J M Seddon

Publications and source records attributed to J M Seddon.

At least 91 records · Page 5Linked to original sources
PubMed1992

Development of the 'Activities of Daily Vision Scale'. A measure of visual functional status.

To develop a method for the evaluation of visual function in subjects with cataracts, the authors identified 20 visual activities and categorized them into five subscales (distance vision, near vision, glare disability, night driving, and daytime driving) that comprised the Activities of Daily Vision Scale (ADVS). Each subscale in the ADVS was scored between 100 (no visual difficulty) and 0 (inability to perform the activity because of visual difficulty). In 334 subjects scheduled for cataract extraction (mean age 75 +/- 9 years, 67% women), ADVS scores (mean +/- standard deviation) for each subscale ranged from 44 +/- 31 for night driving to 72 +/- 24 for near vision activities. When administered by telephone, inter-rater reliability coefficients (r) were 0.82 to 0.97 (P < 0.001) for each of the subscales, and test-retest reliability was 0.87 for the scale overall. Cronbach's coefficient alpha was very high for both the in-person (alpha = 0.94) and telephone (alpha = 0.91) formats. Criterion validity, the correlation between visual loss and ADVS score, was -0.37 (P < 0.001) when the ADVS was administered in person and -0.39 (P < 0.001) when it was administered by telephone. Content validity as assessed with factor analysis showed that 88% of the variance of the principal components weighted on one factor. The authors conclude that substantial visual disability is not captured by routine visual testing and that the ADVS is a reliable and valid measure of patient's perception of visual functional impairment.

Activities of Daily Living↗
PubMed1992

Evaluation of skin microtopography as a measure of ultraviolet exposure.

A pilot study was conducted to investigate the use of skin microtopography as a semiquantitative noninvasive method for estimating cumulative sun exposure in epidemiologic studies of eye disease. The subjects received a kit through the mail containing materials needed to make a replica of the skin texture of a sun-exposed area of the hand. Each subject previously had undergone a skin biopsy around the same site to evaluate elastotic degeneration, and all were interviewed about past sun exposures. A gradable skin impression was obtained from 96 of 115 (83%) participants after two mailings. The impressions were graded according to the degree of skin texture alteration using standard photographs; interobserver reliability was 0.73 using a weighted kappa statistic. The impression score was correlated most strongly with age (r = 0.53). Independent predictors of higher impression scores (more skin texture changes) were older age, cigar or pipe smoking, less education, lighter iris color, lighter skin color, male gender, and tendency to sunburn. After adjustment for age and the other predictor variables, the biopsy score was not correlated with the impression grade (r = 0.18, P = 0.13). Behaviors indexing sun exposure were not correlated with microtopography. These results suggest that skin microtopography as done in this study reflects aging from intrinsic parameters more than from actinic damage.

Adolescent↗
PubMed1991

Retinal pigment epithelial tears associated with trauma.

Two previously healthy patients, a 66-year-old man with blunt trauma to the right eye, and a 28-year-old man with head trauma from a motorcycle accident, were observed to have parafoveal retinal pigment epithelial tears after injury. In both patients, fluorescein angiography demonstrated mottled window defects in the areas of the tears, and blocked fluorescence in the areas of the rolled-up pigment epithelium. Neither eye had evidence of pigment epithelial detachments. We hypothesize that this unusual phenomenon is caused by an acute tractional force oriented tangentially to the macular plane, the result of a rapid spherically expansile deformation of the globe during trauma.

Accidents, Traffic↗
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↗
PubMed1991

Falls in elderly patients with glaucoma.

We analyzed the determinants of serious falls among 489 ambulatory elders aged 65 years and older who received a comprehensive examination at a glaucoma consultation service. For the previous year, at least one fall requiring medical attention or restricted activity was reported by 9.6% (95% confidence interval [CI], 7.0% to 12.2%) of participants. Using logistic regression to adjust for potential confounding variables, the greatest single risk factor for falls was the use of nonmiotic topical eye medications (odds ratio [OR], 5.4; 95% Cl, 1.8 to 16.4). Additional risk factors for falls were female sex (OR, 2.3; 95% Cl, 1.1 to 4.7) and use of cardiac medications (OR, 2.5; 95% Cl, 1.1 to 5.6). Three other characteristics were also associated with the risk of falls: use of miotic eye medications (OR, 3.2; 95% Cl, 1.0 to 10.1); visual field impairment of 40% or greater (OR, 3.0; 95% Cl, 0.94 to 9.8); and use of sedatives (OR, 2.4; 95% Cl, 0.89 to 6.7). These findings suggest that ocular and systemic medications are the major predictors of falls even in this elderly population seeking ophthalmologic care for glaucoma. Medications appear to pose a greater risk for falls than even major visual impairment.

Accidental Falls↗
PubMed1991

Low-dose aspirin and risks of cataract in a randomized trial of US physicians.

Observational studies have raised the question of a possible benefit of aspirin on the development of cataract. The Physicians' Health Study, a randomized double-masked placebo-controlled trial among 22,071 male physicians, aged 40 to 84 years, provided the opportunity to collect information about whether low-dose aspirin therapy (325 mg on alternate days) affects the development or extraction of cataract. There were 173 age-related cataracts among those physicians assigned to aspirin therapy and 180 among those given placebo (relative risk, 0.95; 95% confidence interval, 0.74 to 1.22). Cataract extractions were less frequent in the aspirin than in the placebo group, but this difference was not statistically significant (relative risk, 0.80; 95% confidence interval, 0.56 to 1.15). Among younger men (aged 40 to 59 years), the relative risks were 0.62 (95% confidence interval, 0.40 to 0.94) for cataract development and 0.67 (95% confidence interval, 0.38 to 1.31) for cataract extraction. These randomized trial data tend to exclude any large benefit of aspirin. While the overall findings concerning cataract development seem to be null, the data on extraction of age-related cataract, while not statistically significant, cannot exclude a possible small to moderate benefit of alternate-day aspirin therapy on the extraction of age-related cataract.

Adult↗
PubMed1991

Survival of patients with metastases from uveal melanoma.

The authors evaluated a series of 145 consecutive patients with metastases from uveal melanoma, after proton beam irradiation, to assess the effect of early diagnosis and treatment for metastases on survival. Metastases were diagnosed between 7 weeks and 8.3 years (median, 2.4 years) after proton beam irradiation. Most patients (n = 94) were symptomatic before diagnosis; the remainder were first detected during screening examination. Liver involvement was documented in nearly all patients (n = 136). The majority of patients had died from metastases by the close of the study (n = 137). Significantly longer survival occurred among patients diagnosed during screening examination (P = 0.004) and among young patients (P = 0.03). The majority of patients received some form of treatment for metastases (69%). Median survival was 2.0 months for patients receiving no treatment compared with 5.2 months for those receiving treatment for metastases (P = .0001). However, the overall 1-year survival rate was poor (13%). Prophylactic adjuvant therapy could be explored as a means to increase disease-free survival in patients with uveal melanoma.

Adult↗
PubMed1990

An inverse face-centered cubic phase formed by diacylglycerol-phosphatidylcholine mixtures.

Fully hydrated unsaturated diacylglycerol-phosphatidylcholine mixtures are found to adopt an inverse face-centered cubic phase, of crystallographic cubic aspect 15. The same behavior is observed for either the 1,2- or 1,3-isomer of the diacylglycerol. This Q15 cubic phase, of probable space group Fd3m (Q227), occurs between an inverse hexagonal (HII) phase and an inverse micellar (L2) solution, with increasing diacylglycerol concentration, which implies that the mean curvature of the interface is more negative than that of the HII phase. This behavior is quite different from that of the more usual bicontinuous inverse cubic phases Pn3m (Q224), Im3m (Q229), and Ia3d (Q230), which normally occur between the lamellar L alpha and the HII phases. One possible structure for the Fd3m cubic phase has recently been proposed (Mariani, P., Luzzati, V., & Delacroix, H. (1988) J. Mol. Biol. 204, 165-189), consisting of tetrahedrally arranged clusters of inverse micelles surrounded by a continuous cage of tetrahedrally connected water/lipid (inverse) channels.

Densitometry↗
PubMed1990

Host factors, UV radiation, and risk of uveal melanoma. A case-control study.

Uveal melanoma threatens life, as well as sight. To evaluate the effect of constitutional factors and UV radiation on the risk of uveal melanoma, 197 cases in New England were compared with 385 matched population controls, identified by random-digit dialing, and 337 cases residing within the United States were compared with 800 sibling controls. In the population-based comparison, estimated relative risks (RRs) of uveal melanoma, after adjustment for other factors, were elevated for the following: ancestry from more northern latitudes with a substantially elevated risk for Northern European ancestry (RR, 6.5; 95% confidence interval [CI], 1.9 to 22.4) and more than a twofold risk for British ancestry (RR, 2.4; 95% CI, 1.1 to 5.1), as compared with Southern European or other Mediterranean heritage; light skin color as compared with dark (RR, 3.8; 95% CI, 1.1 to 12.6); and 10 or more cutaneous nevi as compared with none (RR, 2.7; 95% CI, 1.5 to 4.9). There was a statistically significant trend for increasing risk with more northern heritage and more moles. Southern residence (below latitude 40 degrees N) for more than 5 years also increased risk (RR, 2.8; 95% CI, 1.1 to 6.9), as compared with none. In both comparisons, use of sunlamps was a risk determinant (RR, 3.4; 95% CI, 1.1 to 10.3 with random-digit dialed controls and RR, 2.3; 95% CI, 1.2 to 4.3 with sibling controls, comparing occasional or frequent use to never use), as was intense sun exposure (RR, 1.7; 95% CI, 0.9 to 3.0 and RR, 2.1; 95% CI, 1.4 to 3.2, respectively). However, birthplace below latitude 40 degrees N and outdoor work were associated with a lower risk.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Relative survival rates after alternative therapies for uveal melanoma.

Survival in a group of 556 patients with uveal melanoma treated by proton beam irradiation with a median follow-up of 5.3 years was compared with that of 238 patients enucleated during the same 10-year period as irradiated patients (July 1975 to December 1984) with a median follow-up of 8.8 years, and 257 patients enucleated during the preceding 10 years (January 1965 to June 1975) with a median follow-up of 17.0 years. Adjustments were made for known prognostic factors including age, tumor location, tumor height, and clinical estimate of tumor diameter (for enucleated patients this was estimated in a regression equation relating histologic to clinical measurement). The overall rate ratio for all cause mortality was 1.2 (95% confidence interval, 0.9-1.6) for the concurrent enucleation series versus proton beam, and 1.6 (95% confidence interval, 1.2-2.1) for the earlier enucleation series versus proton beam. Relative rates of metastatic death, cancer death, and all cause mortality comparing alternative treatments were found to vary with time after treatment. Interval-specific rate ratios were evaluated using proportional hazards models fitted to separate time intervals after treatment. For all three outcomes, rate ratios were over two and statistically significant for the first 2 years after treatment and closer to one and nonsignificant after year 6 comparing the two enucleation groups with proton beam. Results suggest that treatment choice has little overall influence on survival in patients with uveal melanoma.

Adult↗
PubMed1990

Case-control study of idiopathic retinal detachment.

A case-control study of idiopathic, rhegmatogenous retinal detachment (IRD) was conducted to investigate potential risk factors for developing IRD. These included some factors reported previously, such as cardiovascular disease, and some not under suspicion, such as cigarette smoking and iris colour. Cases (n = 198) were incident cases of IRD who were hospitalized for surgical repair of their detachments. Controls (n = 655) were patients hospitalized for conditions unrelated to suspected risk factors for IRD. The risk of IRD appeared to increase with increasing age, and the relative risk for self-reported myopes, compared with non-myopes, was elevated (RR = 3.4, 95% CI = 2.3 - 5.0). The relative risk of IRD was decreased in current smokers (RR = 0.5, 95% CI = 0.3 - 0.8); although there was not a significant trend of decreasing relative risk with increasing amount smoked, the estimate was lowest in those who smoked most heavily. Risk did not appear to be related to gender, eye colour, history of myocardial infarction, or history of hypertension.

Adolescent↗
PubMed1990

Evaluation of an iris color classification system. The Eye Disorders Case-Control Study Group.

A system for classification of iris color based on standard photographs, developed for use in a multicenter study, is described. Categories of iris color are distinguished based on predominant color (blue, gray, green, light brown, or brown) and the amount of brown or yellow pigment present in the iris. Two trained readers independently graded 339 iris photographs; discrepancies in grades were adjudicated. Measures of interobserver reliability were 0.76 by kappa for exact agreement and 0.97 for weighted kappa. The distribution of iris color grades demonstrates that the system achieved an appropriate level of detail within the authors' study population, which included patients with various racial backgrounds from five urban clinical centers. This simple, reliable classification system for iris color is offered for use in clinical research.

Analysis of Variance↗
PubMed1990

An NMR blood test for uveal melanoma?

In a recent article a simple nuclear magnetic resonance (NMR) blood test was suggested for the detection of the presence of cancer. The test's sensitivity to uveal melanoma of both pre- and posttreatment status has been investigated. Cases in this study were 95 patients with uveal melanoma, and controls were 70 participants in an ongoing case control study of retinal eye disease being conducted at the Massachusetts Eye and Ear Infirmary. Proton NMR evaluations at 4.7 T (200 MHz) were performed on plasma obtained from EDTA and citrated blood samples. The average line-width values were calculated from each spectrum. Statistical analysis revealed that mean proton NMR line widths were essentially equal for patients with treated (18.7 Hz) and untreated tumors (18.4 Hz) and for controls (18.5 Hz). Results based on this data set suggest that proton NMR spectroscopy has little predictive power in the detection of uveal melanoma or in the monitoring of therapy.

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↗
PubMed1989

Conservative treatment of uveal melanoma: local recurrence after proton beam therapy.

Twenty-three of 1006 (2.3%) uveal melanoma patients treated with proton beam therapy at the Harvard Cyclotron Laboratory between July 1975 and December 31, 1986 received additional treatment for documented (15 patients) or suspected (eight patients) tumor growth in the irradiated eye. Growth within the initially irradiated volume was documented at Massachusetts Eye and Ear Infirmary in 12 patients. Documented growth occurred in nine of 665 (1.4%) patients with small and intermediate size tumors, at times after treatment ranging from 6 to 48 months (median 16 months), and in three of 341 (.9%) patients with large tumors at 7, 11, and 12 months after treatment. Melanoma growing totally outside the treated volume was also documented in three additional patients at 7, 9, and 45 months; two of these were thought to be "ring melanomas". Eight patients had the treated eye removed elsewhere for suspected tumor growth. The additional treatment in these 23 patients was conservative in nine patients (repeat proton irradiation in five and laser photocoagulation in four). Thirteen underwent immediate enucleation and one had orbital exenteration. Ultimately, 17 of the 23 eyes (74%) were removed. Estimated probability of local control of the melanoma within the irradiated eye at 60 months was 96.3 +/- 1.5%. Dose distributions to the 12 patients with documented local failure within the irradiated volume were analyzed. Ten tumors recurred marginally in an area receiving less than the prescribed dose of 70 CGE (CGE = Cobalt Gray Equivalents = proton Gy X RBE 1.1), whereas only two recurred in the volume receiving full dose. Based on these data, it appears that a dose of 70 CGE in five fractions is associated with very high rates of local control in human uveal melanoma. It is reasonable to consider initiating studies using a lower total dose or a more protracted course, to determine if some of the observed complications are dose-related.

Adult↗