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Biomedical subjects

G S Rubin

Publications and source records attributed to G S Rubin.

At least 19 recordsLinked to original sources
PubMed2006

Visual function and quality of life following vitrectomy and epiretinal membrane peel surgery.

AIM: To investigate the effect of epiretinal membrane (ERM) peel on patients' health related quality of life (HR-QOL) and to explore the association between self reported HR-QOL and conventional measures of visual function. METHODS: The National Eye Institute 25 Item Visual Function Questionnaire (VFQ-25) and the 36 Item Short-Form Health Survey (SF-36) were self administered by 20 patients before and 4 months following surgery. Preoperative and postoperative data collected included logMAR near and distant visual acuity (VA), contrast sensitivity, and metamorphopsia. Questionnaire scores were compared preoperatively and postoperatively and their correlation with traditional methods of visual function evaluation analysed. RESULTS: Postoperatively there was no significant improvement in mean logMAR VA. However, eight (40%) subjects improved by two or more ETDRS lines and nine eyes (45%) reached a final VA of 6/18 or better. Metamorphopsia decreased significantly (p = 0.019) and there was significant improvement in VFQ-25 mean scores for the general vision (p = 0.03), distance activities (p = 0.05), and composite score (p = 0.03). Baseline binocular VA was significantly correlated with baseline VFQ-25 composite score (r = 0.631, p = 0.004). CONCLUSIONS: ERM surgery appears to improve patients' subjective perception of visual function as indicated by higher composite scores in VFQ-25 and improved metamorphopsia in the absence of significant improvement in mean logMAR VA.

Adult↗
PubMed2005

Contrast sensitivity as an outcome measure in patients with subfoveal choroidal neovascularisation due to age-related macular degeneration.

PURPOSE: Although visual acuity is the most frequently used primary outcome measure in clinical trials of treatments for choroidal neovascularisation (CNV) due to age-related macular degeneration (AMD), contrast sensitivity may provide valuable additional information. This paper reviews the evidence for using contrast sensitivity as a measure of visual function and as an outcome measure in clinical trials in patients with subfoveal CNV due to AMD. METHODS: Medline database searches were performed to retrieve relevant articles on contrast sensitivity. In addition, articles were included from the authors' knowledge of the literature and from the reference lists of retrieved articles. RESULTS: The published literature demonstrates that contrast sensitivity is an important measure of visual function in patients with subfoveal CNV due to AMD. Most clinical trials of treatments for CNV due to AMD have reported visual acuity as the primary outcome. However, there is evidence that treatment (such as verteporfin therapy) may also provide additional benefits in terms of contrast sensitivity. These benefits may not be completely characterised by measurement of visual acuity alone. CONCLUSIONS: The inclusion of contrast sensitivity as an outcome measure in studies of patients with CNV due to AMD may provide a more complete understanding of the effects of treatment on visual function and the likely benefits for patients.

Activities of Daily Living↗
PubMed2004

Evaluation of a new quantitative technique to assess the number and extent of preferred retinal loci in macular disease.

Patients with scotomas due to macular disease may use more than one preferred retinal locus (PRL) for fixation. We have developed and evaluated an objective, quantitative technique to determine the number of PRLs used during an episode of fixation and the extent of each locus. In five of eight adults with macular disease our techniques consistently indicated the presence of multiple PRLs. Patients with multiple PRLs were more likely to have suffered recent vision loss in the tested eye. Our technique describes fixation more fully than the traditional method of calculating a single bivariate contour ellipse area.

Adult↗
PubMed2003

Fundus autofluorescence imaging compared with different confocal scanning laser ophthalmoscopes.

BACKGROUND: With the advent of confocal scanning laser ophthalmoscopes (cSLO), fundus autofluorescence (FAF) resulting mainly from lipofuscin accumulation on the level of the retinal pigment epithelium can be visualised in vivo. Various cSLOs are available to document FAF. The authors analysed and compared results of FAF using three different instruments. METHODS: Eight eyes of eight normal volunteers and 18 eyes of 12 patients with different retinal diseases (age related macular degeneration, macular dystrophy, central serous retinopathy) were examined. FAF images were recorded from each subject with the Heidelberg retina angiograph (HRA), the Rodenstock cSLO (RcSLO) and the Zeiss Prototype SM 30-4024 (ZcSLO). For excitation an argon laser (488 nm) was used (barrier filter: HRA 500 nm; RcSLO 515 nm; ZcSLO 521 nm). 32 FAF images were aligned and averaged using the same software for all cSLOs. FAF distribution was measured and grey scale values as well as root mean square (RMS) contrast were compared. RESULTS: Mean age of all subjects was 55.5 (SD 21.4) years. The maximum grey scale value averaged across all eyes was 76.19 (39.34) for the HRA, 61.44 (22.12) for the ZcSLO and 37.0 (9.97) for the RcSLO. The RMS contrast was 0.46 (0.20) for the ZcSLO, 0.40 (0.12) for the HRA, and 0.13 (0.05) for the RcSLO. The differences between the cSLOs were statistically significant with higher grey scale levels and more contrast for the HRA and ZcSLO than the RcSLO (repeated measures ANOVA; p<0.0001). The differences between the HRA and the ZcSLO were not significant (post hoc comparisons; p<0.05). CONCLUSIONS: All cSLOs allow clinically useful FAF imaging in retinal diseases. However, grey scale levels and contrast were much lower on the RcSLO. Therefore, RcSLO images appear much darker than HRA or ZcSLO images. Furthermore, not all cSLOs have a fixed photodetector gain and a standardised value for the argon laser amplification, which is mandatory for an absolute comparison of FAF imaging results.

Aged↗
PubMed2001

The association of multiple visual impairments with self-reported visual disability: SEE project.

PURPOSE: This report examines the relationship between psychophysical measures of visual impairment and self-reported difficulty with everyday visual tasks in a population-based sample of individuals 65 years of age and older. METHODS: Community-dwelling residents (n = 2520) of Salisbury, MD, between the ages of 65 and 84 were recruited for the study. Visual acuity under normal and low luminance, contrast and glare sensitivity, stereoacuity, and visual fields were measured. Subjective physical disability was assessed with the Activities of Daily Vision Scale (ADVS). RESULTS: In multiple regression analyses adjusted for demographic factors, cognitive status, depression, and number of comorbid medical conditions, each of the vision tests except low luminance acuity was independently associated with lower ADVS scores. The analyses indicate that a factor of 2 reduction in visual acuity or contrast sensitivity, comparable with that observed in mild to moderate lens opacity, was associated with a three- to fivefold odds of reporting difficulty with daily tasks. Although age alone was a significant risk factor for disability, it was not associated with overall ADVS score, once visual impairment and other chronic medical conditions were taken into account. CONCLUSIONS: Visual acuity, contrast and glare sensitivity, stereoacuity, and visual fields are significant independent risk factors for self-reported visual disability in an older population. Visual impairment defined by acuity alone is not the only dimension of the association with subjective disability. Additional vision measures are required to understand the impact of vision loss on everyday life.

Activities of Daily Living↗
PubMed2000

Mixed lens opacities and subsequent mortality.

BACKGROUND: Previous studies have found an association between cataract or lens opacity and increased risk of mortality. Further work on determining explanatory factors for this association is needed. OBJECTIVES: To determine, in a population-based cohort of older persons, the 2-year risk of death associated with different types of lens opacities; whether an association of mortality and lens opacity is explained by confounding risk factors such as smoking, diabetes, age, race, and sex, which are known to be related to opacity and mortality; whether lens opacity is a marker for health status; and whether there are differences in cause-specific mortality for persons with and without lens opacity. MAIN OUTCOME MEASURE: Two-year mortality rate. METHODS: The Salisbury Eye Evaluation Project consists of a random sample of 2520 residents of Salisbury, Md, aged 65 to 84 years. At baseline, lens photographs were taken to document nuclear, cortical, posterior subcapsular cataract, and mixed opacities. Data on education, smoking, alcohol use, hypertension, diabetes and other comorbid conditions, handgrip strength, and body mass index were also collected. Two-year follow-up was conducted for mortality and cause of death. RESULTS: Nuclear opacity, particularly severe nuclear opacity, and mixed opacities with nuclear were significant predictors of mortality independent of body mass index, comorbid conditions, smoking, age, race, and sex (mixed nuclear: odds ratio, 2.23; 95% confidence interval, 1.26-3.95). CONCLUSION: Lens opacity status is an independent predictor of 2-year mortality, an association that could not be explained by potential confounders.

Aged↗
PubMed2000

Causes of blindness and visual impairment in a population of older Americans: The Salisbury Eye Evaluation Study.

OBJECTIVE: To determine the causes of blindness and visual impairment in a population-based sample of older Americans. METHODS: A random sample of 3821 residents of Salisbury, Md, between the ages of 65 and 84 years was identified from Medicare records. Sixty-six percent (2520 persons) agreed to undergo an eye examination; 26% of the participants were African American. The clinical examination included acuity testing with an Early Treatment Diabetic Retinopathy Study chart and standardized refraction testing for those with a visual acuity worse than 20/30, slitlamp and dilated retinal examination by an ophthalmologist, tonometry, lens and fundus photography, and a suprathreshold visual field test. Visual impairment was defined as a best-corrected acuity in the better-seeing eye worse than 20/40 and better than 20/200, while blindness was acuity in the better-seeing eye of 20/200 or worse. For those with a visual acuity worse than 20/40 in either eye, one or more causes were assigned by an ophthalmologist and a final cause for each eye was confirmed by a panel of 3 subspecialty ophthalmologists (O.D.S., H.A.Q., and S.B.B.) based on all available evidence. RESULTS: Bilateral presenting acuity worse than 20/40 increased from 4% in the 65- to 74-year age group to 16% in the 80- to 84-year age group. One third of those with presenting acuity worse than 20/40 improved to 20/40 or better with refraction. Overall, 4.5% had a best-corrected acuity worse than 20/40. African Americans were more likely to remain visually impaired than were whites despite refraction (odds ratio [95% confidence interval], 1.7 [1.1-2.6]). Whites were most often impaired or blind from age-related macular degeneration (1.2% vs 0.5%; P=.09). African Americans had higher rates of impairment and blindness from cataract or posterior capsular opacification (2.7% vs 1.1%; P=.006), glaucoma (0.9% vs 0.1%; P=.006), and diabetic retinopathy (1.2% vs 0.2%; P=. 004). CONCLUSIONS: More than half of those with visual impairment or blindness had conditions that were either surgically treatable or potentially preventable. African Americans had a disproportionate number of blinding diseases, particularly those amenable to eye care intervention. Targeted interventions for specific populations to increase appropriate eye care use would greatly improve vision and function in older Americans. Arch Ophthalmol. 2000;118:819-825

Aged↗
PubMed2000

Reading with eccentric fixation is faster in inferior visual field than in left visual field.

PURPOSE: People with central field loss tend to fixate so that information falls in the inferior or left visual field. Studies of reading from a page of text suggest that using inferior field is advantageous relative to using left visual field. In this study, we investigated whether reading without eye movements in normal peripheral vision is better when text is presented in inferior or left visual field. METHODS: Reading rates were determined for retinally stabilized rapid serial visual presentation sentences of seven letter sizes, presented at 5 degrees in inferior and left visual field of six normal observers. RESULTS: When print size is appropriately magnified for peripheral viewing, reading speed in inferior field is faster than in left visual field. There is no significant difference between inferior and left visual field in the print size required to reach maximum reading speed. CONCLUSIONS: For reading tasks not involving eye movements, there is an advantage in eccentrically fixating such that text falls in inferior rather than left visual field.

Adult↗
PubMed2000

Monocular versus binocular visual acuity as measures of vision impairment and predictors of visual disability.

PURPOSE: To examine the relationship between monocular and binocular visual acuities as predictors of visual disability in a population-based sample of individuals 65 years of age and older. METHODS: Two thousand five hundred twenty community-dwelling residents of Salisbury, Maryland, between the ages of 65 and 84 years of age were recruited for the study. Corrected visual acuity was measured monocularly and binocularly using ETDRS charts. Reading speed, face discrimination, and self-reported difficulty with visual tasks were also determined. RESULTS: Binocular acuity is predicted with reasonable accuracy by acuity in the better eye alone, but not by the widely used American Medical Association (AMA) weighted-average algorithm. The AMA algorithm significantly underestimates binocular acuity when the interocular acuity difference exceeds one line. Monocular acuity and binocular acuity were significantly better predictors of reading speed than the AMA weighted score or a recently proposed Functional Vision Score (FVS). Monocular acuity in the better eye, binocular acuity, and the AMA and FVS algorithms were equally good predictors of self-reported vision disability. None of the acuity measures were good predictors of face recognition ability. CONCLUSIONS: The binocular acuities of older individuals can be inferred from measures of monocular acuity. There is little evidence for binocular inhibition when the monocular acuities in the two eyes are unequal, as opposed to the widely used AMA algorithm for computing binocular visual impairment. For tasks that are strongly associated with visual acuity, such as reading, this association can be captured from measures of monocular acuity and does not require separate assessment of binocular acuity.

Aged↗
PubMed1999

Determination of risk factor associations with questionnaire outcomes: a methods case study.

Increasingly in biomedical studies, health status is inferred through a series of questionnaire item responses. Challenges for analyzing associations between such responses and risk factors include multiplicity-many indicators must be combined to derive summary statements about health status, and measurement error-persons' self-report fluctuates due to causes other than substantive health changes. In order to deal with these challenges, the authors propose a strategy which comprises three methods: 1) score the item responses, then regress the score on predictors; 2) regress each item response on predictors, accounting for within-person associations; and 3) summarize and analyze the item responses jointly, using a latent variable model. The authors develop modeling and diagnostic procedures for method 3. They then show how the three-method analytic strategy can be used to solve the problem of determining which aspects of vision are associated with self-reported functioning in activities that require seeing at a distance. They demonstrate that methods 2 and 3 illuminate basic findings from method 1 by adding specificity, describing patterns as well as severities of health impairments, and identifying isolated items that relate to risk factors differentially than others. They conclude that the three-method strategy specifies how risk factors determine questionnaire-based health outcomes substantially better than any of the methods in isolation.

Activities of Daily Living↗
PubMed1999

Reading with central field loss: number of letters masked is more important than the size of the mask in degrees.

When the center of a readers, visual field is blocked from view, reading rates decline and eye movement patterns change. This is true whether the central visual field is blocked artificially (i.e. a mask) or through disease (e.g. a retinal scotoma due to macular degeneration). In past studies, when mask size was defined in terms of the number of letters masked from view, reading rates declined sharply as number of letters masked increased. Patients with larger central scotomas (in degrees of visual angle) also read slower. We sought to determine whether number of letters masked or size of the mask in degrees is the predominant factor affecting reading rates and eye movement behavior. By matching number of letters masked across several mask sizes (and compensating for reduced acuity in the periphery), we found that number of letters masked is the more important factor until mask size is quite large (> or = -7.5 degrees) and number of letters masked from view is more than seven.

Adult↗
PubMed1999

Reading with simulated scotomas: attending to the right is better than attending to the left.

Persons with central field loss must learn to read using eccentric retina. To do this, most adopt a preferred retinal locus (PRL), which substitutes for the fovea. Patients who have central field loss due to age-related macular degeneration (AMD), most often adopt PRL adjacent to and to the left of their scotoma in visual field space. It has been hypothesized that this arrangement of PRL and scotoma would benefit reading. We tested this hypothesis by asking normally-sighted subjects to read with the left or right half of their visual field plus 3.2 degrees in the contralateral field masked from view. Letter identification, word identification, and reading were all slower when only the information in the left visual field was available. This was primarily due to the number of saccades required to successfully read to stimuli. These data imply that patients would be better off with PRL to the right of their scotoma than to the left for the purposes of reading.

Eye Movements↗
PubMed1999

The effects of simulated cataract on reading with normal vision and simulated central scotoma.

Reading rates are slower for persons with low vision than for normally-sighted persons. This study investigated the change in reading performance and reading eye movements when we simulated the two most common causes of low vision--central field loss and cataract--and their combination (scotoma + cataract). Three subjects read sentences with each of these simulated impairments at five different letter sizes. They required larger letters to read with the cataract or scotoma than they did with normal vision, and larger still to read with scotoma + cataract; the change in eye movements relative to normal vision was similar across conditions. When reading large letters (1.61 degrees), the cataract had almost no effect, while the scotoma and scotoma + cataract reduced reading rate for two of the subjects. The cataract had a greater impact on performance relative to normal vision for these same two subjects, while for the third subject the cataract had a greater impact with the scotoma in place. Cataract extraction tends to be postponed in patients with central field loss because it is not perceived to be beneficial. The findings from this study, as well as others, suggest that patients with central field loss would benefit from cataract extraction.

Adult↗
PubMed1999

Eye care utilization by older Americans: the SEE Project. Salisbury Eye Evaluation.

OBJECTIVE: To determine eye care utilization patterns among older Americans, particularly characterizing those who sought different types of providers, and the predictive factors for seeking eye care services in general and among those with diabetes and those with visual loss. DESIGN AND PARTICIPANTS: The SEE Project, a population-based survey of 2520 persons aged 65 to 84 in Salisbury, Maryland, provided cross-sectional data on eye care use. Questions on eye care use, demographics, medical history, and other factors were asked on the home interview. MAIN OUTCOME MEASURES: Use of an eye care provider in the previous year, with additional outcomes of use of different types of eye care providers. RESULTS: Blacks were significantly less likely to see any type of eye care provider over 1 year: 50% versus 69% among whites. Those who reported having a vision problem, those with more education, and those in the older age groups were significantly more likely to see either an ophthalmologist or an optometrist. Diabetes and driving a car were predictive factors for seeing an ophthalmologist but not for seeing an optometrist. Self-report of diabetes and eye care problems, and being a current driver, were predictive of seeing an eye care professional among those with visual impairment. CONCLUSIONS: Although blacks are known to be at greater risk for several age-related eye diseases, they are much less likely to see an eye care provider. Interventions that remove barriers to eye care services should be considered.

Aged↗
PubMed1999

Who participates in population based studies of visual impairment? The Salisbury Eye Evaluation project experience.

PURPOSE: To describe characteristics of respondents and nonrespondents to a home questionnaire and comprehensive clinical examination in a population of elderly Americans. METHODS: The SEE project is a population-based study of age-related eye diseases, visual impairment, and functional status of individuals aged 65 to 84. Potential participants were identified using the Health Care Financing Administration Medicare data base for Salisbury, MD: After sending out an introductory letter, a trained interviewer visited potential participants in their homes, obtained their consent to participate, administered a short screening interview that included questions about their general health and vision, and administered an extensive questionnaire on their diet, medical history, and difficulty performing activities related to vision. The interviewer then scheduled an appointment for the participants to visit a central site for an exam. Potential participants could fall into one of two refusal groups; refusal to take part in the study before the home questionnaire or prior to the clinic visit. RESULTS: The overall response rate for the clinic visit was 65%. Compared to individuals with complete exams, the two groups of refusals were older, less likely to have any college education, more likely to report poor health status, and more likely to need help with Independent Activities of Daily Living (IADL's). Participants with complete home questionnaires that failed to come to the clinic were more likely to have Mini-Mental scores below 25. There were not significant differences by race, gender, or self reported vision status among the three groups. CONCLUSIONS: Population-based studies requiring an in-clinic examination may selectively under-sample those with health and mental difficulties. These differential responses may introduce bias in the study results and need to be addressed when assessing the burden, type and severity of disease in the community. However, self-report of visual status was similar among refusals and participants in this study on vision.

Activities of Daily Living↗