Biomedical subjects

Gary S Rubin

Publications and source records attributed to Gary S Rubin.

At least 19 recordsLinked to original sources

PubMed2006

Clinical assessment of two new contrast sensitivity charts.

BACKGROUND: Contrast sensitivity measurement in UK clinical practice is most commonly performed with the Pelli-Robson chart. AIMS: To compare the repeatability of two new contrast sensitivity charts and to measure their agreement with the Pelli-Robson charts. METHOD: Contrast sensitivity was measured monocularly using two versions of the Mars letter contrast sensitivity chart, two presentations on the Test Chart 2000 and two versions of the Pelli-Robson chart. Bland-Altman techniques were used to assess repeatability and agreement. RESULTS: 53 subjects were recruited with visual acuity from 6/4 to 6/72. The coefficient of repeatability was 0.182 for the Pelli-Robson chart, 0.121 for the Mars chart and 0.238 for Test Chart 2000. Limits of agreement with the Pelli-Robson chart were -0.29 to +0.15 log units for the Mars letter contrast sensitivity chart and -0.32 to +0.78 log units for the Test Chart 2000. For patients with poor contrast sensitivity, the limits of agreement between the Test Chart 2000 and the Pelli-Robson chart improved from -0.33 to +0.15 log units. CONCLUSION: In a population of hospital ophthalmology patients, the coefficient of repeatability is better for the Mars chart and worse for the Test Chart 2000 when compared with the Pelli-Robson chart. The electronic test chart does not agree well with the Pelli-Robson chart, although this might simply be due to the performance of liquid crystal display screens at low contrast levels. The Mars letter contrast sensitivity chart shows good validity and reasonable agreement with the Pelli-Robson chart.

Adult↗

PubMed2006

Acuity, crowding, reading and fixation stability.

People with age-related macular disease frequently experience reading difficulty that could be attributed to poor acuity, elevated crowding or unstable fixation associated with peripheral visual field dependence. We examine how the size, location, spacing and instability of retinal images affect the visibility of letters and words at different eccentricities. Fixation instability was simulated in normally sighted observers by randomly jittering single or crowded letters or words along a circular arc of fixed eccentricity. Visual performance was assessed at different levels of instability with forced choice measurements of acuity, crowding and reading speed in a rapid serial visual presentation paradigm. In the periphery: (1) acuity declined; (2) crowding increased for acuity- and eccentricity-corrected targets; and (3), the rate of reading fell with acuity-, crowding- and eccentricity-corrected targets. Acuity and crowding were unaffected by even high levels of image instability. However, reading speed decreased with image instability, even though the visibility of the component letters was unaffected. The results show that reading performance cannot be standardised across the visual field by correcting the size, spacing and eccentricity of letters or words. The results suggest that unstable fixation may contribute to reading difficulties in people with low vision and therefore that rehabilitation may benefit from fixation training.

Adult↗

PubMed2006

Gaze changes with binocular versus monocular viewing in age-related macular degeneration.

PURPOSE: To determine and explain gaze changes during binocular versus monocular viewing in patients with age-related macular degeneration (AMD). DESIGN: Cross-sectional study. PARTICIPANTS: Twenty-nine patients with bilateral late-stage AMD. METHODS: Distance acuity and fundus pathologic features were evaluated. Eye position was recorded while viewing a circular fixation target under monocular and binocular viewing conditions using an infrared eye tracker (SMI Gazetracker, SensoMotoric, Germany; Eyelink Software 2.04). Gaze changes were quantified by calculating the mean x-coordinate and y-coordinate eye position of the center of the bivariate contour ellipse area for a 30-second fixation task under both viewing conditions. Retinal loci used for monocular fixation for each eye were determined using the scanning laser ophthalmoscope (SLO; SLO 101, Rodenstock, Munich, Germany). MAIN OUTCOME MEASURE: Gaze position. RESULTS: Nine patients showed no shift in gaze position from monocular to binocular viewing. Three patients demonstrated a shift in both eyes, and 17 patients demonstrated a shift in only 1 eye. The mean shift was 4.7+/-5 degrees (standard deviation). The shift in gaze position in the worse eye was predictive of the distance between the 2 monocular preferred retinal loci (PRLs; better and worse eye; r(2) = 0.59; P<0.0001), whereas there was no association between the shift in gaze position in the better eye and distance (r(2) = 0.00; P = 0.91). CONCLUSIONS: Most AMD patients shift gaze position in 1 or both eyes when viewing binocularly compared with monocularly. These changes suggest that different retinal locations are used for fixation under the 2 viewing conditions. The SLO data showed that these patients are likely to demonstrate monocular PRLs that fall on noncorresponding areas. These results may have implications for the effective development of eccentric viewing and binocular behavior of AMD patients.

Aged↗

PubMed2006

Reading with central scotomas: is there a binocular gain?

PURPOSE: The purpose of this study was to compare reading performance under binocular versus monocular viewing conditions in patients with bilateral age-related macular degeneration (AMD). METHODS: Twenty-two patients with AMD participated. Distance acuity, reading acuity, and contrast sensitivity were recorded binocularly and monocularly with the better eye. An infrared eye tracker recorded eye movements during reading. Reading speed and reading eye movement parameters, including number of fixations and regressions, fixation duration, and number of saccades to find the next line, were calculated for both viewing conditions. The difference between binocular and monocular performance (binocular gain) was computed. Regression analysis was used to determine whether intraocular differences in distance and reading acuity and contrast sensitivity were predictive of binocular gain. RESULTS: Reading speed when using both eyes was highly correlated with the reading speed for the better eye. There was a small, but not significant, advantage of binocular viewing (6.9 words/minute, p = 0.33). No significant difference was detected in any eye movement parameters when comparing both eyes with the better eye. Although some patients showed either positive or negative binocular gain, the amount of gain was not predicted by intraocular differences in acuity or contrast sensitivity. CONCLUSIONS: Overall, there was no significant difference between binocular and monocular reading performance in patients with AMD.

Aged, 80 and over↗

PubMed2006

The effect of font and line width on reading speed in people with mild to moderate vision loss.

PURPOSE: The aim of this study was to evaluate the effects of print size, typeface, and line width on reading speed in readers with mild to moderate sight problems. METHODS: A total of 43 patients, most of whom had mild cataract or glaucoma with acuity 6/30 or better (median age = 72; range = 24-88 years), read aloud a selection of texts presented randomly in four sizes (10, 12, 14 and 16 point), for each of four typefaces [Foundry Form Sans (FFS), Helvetica (HV), Tiresias PCfont (TPC), Times New Roman (TNR)] at a standard line width of 70 characters and a viewing distance of 40 cm. A subset of letter sizes and typefaces were tested at two additional line widths (35, 90). RESULTS: As expected, reading speed increased with print size from a median of 144 words min(-1) for 10-point text to 163 words min(-1) for 16-point text (repeated measures anova, p < 0.0001). There was also a significant effect of typeface with TPC being read about 8 words min(-1) faster, on average, than the other fonts (159 words min(-1) for TPC vs 151 words min(-1) for the other fonts, p < 0.0001). However fonts of the same nominal point size were not equivalent in actual size. When adjusted for the actual horizontal and vertical space occupied, the advantage of TPC was eliminated. There was no effect of line width (p > 0.3). Data from the present study were extrapolated to the general population over age 65. This extrapolation indicated that increasing minimum print size from 10 points to 16 points would increase the proportion of the population able to read fluently (>85 words min(-1)) from 88.0% to 94.4%. CONCLUSION: This study shows that line width and typeface have little influence on reading speed in people with mild to moderate sight problems. Increasing the minimum recommended print size from 10 points to 14 or 16 points would significantly increase the proportion of the population able to read fluently.

Adolescent↗

PubMed2005

Eye movements and reading in macular disease: further support for the shrinking perceptual span hypothesis.

Reduced perceptual span is one factor which limits reading speed in patients with macular disease. This study measured the perceptual span and the number of saccades to locate a target in 18 patients with macular disease and seven control subjects on two occasions separated by up to 12 months. Perceptual span changed by up to two letters. Changes in perceptual span were significantly related to changes in reading speed (r2 = 0.43, p < 0.005), and were independent of changes in the number of saccades used to observe a target (r2 = 0.003, p = 0.62). These findings have important implications for the development of training programmes for patients with macular disease.

Adolescent↗

PubMed2005

Compensatory strategy use identifies risk of incident disability for the visually impaired.

BACKGROUND: Use of compensatory strategies may be a marker for preclinical disability. OBJECTIVE: To determine, among persons who did not report mobility disability, if the reported use of compensatory strategies was a predictor of subsequent disability at 2 years in those who did and did not have visual impairment at baseline. METHODS: Within a population-based sample of 2520 persons aged 65 to 84 years, those who reported no difficulty walking or stair-climbing at baseline (not disabled) were studied. Visual impairment was defined as a visual acuity worse than 20/40, log contrast sensitivity less than 1.5, or more than 30 points missing in the visual field. Use of compensatory strategies at baseline was reported as changing the frequency or method used to walk or climb stairs. Incident disability was defined as report of new difficulty in mobility at 2 years. RESULTS: Those using compensatory strategies at baseline were 3 times more likely to report incident disability in walking and stair-climbing, compared with persons who did not use compensatory strategies. Visual field impairment was the most significant predictor of incident mobility disability of all the vision measures studied. Among those with visual field impairment, users of compensatory strategies were 3 times more likely to report incident walking disability (95% confidence interval, 1.87-5.58) and incident stair-climbing disability (95% confidence interval, 1.86-4.83) compared with those who did not use compensatory strategies. CONCLUSION: Preclinical disability, characterized by use of compensatory strategies in those with no disability, is a predictor for subsequent disability and may help identify patients with visual impairment for whom mobility interventions are warranted.

Activities of Daily Living↗

PubMed2005

Age-related macular disease: how to assess the retina using scanning laser techniques?

Age-related macular disease (AMD) is the leading cause of legal blindness among the elderly in Western nations. The magnitude of the problem will undoubtedly grow, as age is a significant risk factor and the number of people aged 65 and over is projected to increase. The most frequent cause of severe visual loss associated with AMD is irreversible degeneration of the overlying neurosensory retina, caused by the growth of choroidal neovascularization or, alternatively, the development of geographic atrophy of the retinal pigment epithelium. Today, we are able to image the human retina in vivo. Recently developed imaging techniques provide better assessment of retinal pathology than conventional ophthalmoscopy alone. This overview presents the most recent devices available for retinal imaging, which mainly exploit laser technology such as scanning laser ophthalmoscopy. Its basic principles, as well as its characteristics for imaging and functional assessment of the retina, are described. Lastly, potential benefits for clinical routine, rehabilitation strategies in AMD, and future research aspects are discussed.

Aged↗

PubMed2005

Preferred retinal locus development in patients with macular disease.

OBJECTIVE: To observe the development of the preferred retinal locus (PRL) in a group of patients with central scotomas caused by recent onset macular disease (MD). DESIGN: Prospective observational case series. PARTICIPANTS: Twenty-five individuals with bilateral central scotomas caused by MD. All patients had experienced visual loss in their better eye in the 2 weeks before recruitment. METHODS: Patients were assessed at baseline and at 4 further visits for up to 12 months. At each visit, the retinal area used for fixation was assessed using a scanning laser ophthalmoscope, the infrared Gazetracker was used to determine the number of discrete retinal areas used for fixation in 5 positions of gaze, and reading speed was measured using MN-Read-style sentences. RESULTS: All 25 patients developed a PRL within 6 months. Sixteen patients (64%) made an adaptation whereby they were unaware of using an eccentric retinal area for fixation. Multiple fixation loci were exhibited by 11 patients at the end of the study. Nineteen patients used a consistent number of PRLs under all positions of gaze. Reading speed was not associated with PRL location or the presence of multiple PRLs. CONCLUSIONS: All of the patients in this study developed a repeatable preferred retinal locus within 6 months of visual loss in their second affected eye. Reading performance was better in patients who were not aware of using eccentric viewing strategies and who used a repeatable number of PRLs under all positions of gaze. These findings are relevant for counseling patients with MD and for the design of rehabilitation programs for patients with central vision loss.

Adaptation, Ocular↗

PubMed2005

Impaired vision and the ability to take medications.

OBJECTIVES: To assess relationships between vision (contrast sensitivity, stereopsis, visual acuity) and a performance-based measure of ability to implement new medications. DESIGN: Cross-sectional analysis; prospective cohort study. SETTING: Community-based. PARTICIPANTS: Three hundred thirty-five participants aged 73 to 82 in Year 3 of the Women's Health and Aging Study II, a representative sample of the two-thirds least-disabled community-dwelling women. MEASUREMENTS: Hopkins Medication Schedule Pillbox Ratio, a joint measure of accuracy and time, and a performance-based measure of ability to implement a prescription. Participants received written and verbal instructions for taking two medications and were directed to place pills in a pillbox accordingly. Vision assessments: contrast sensitivity (Pelli-Robson letter sensitivity chart), stereopsis (Randot Circles), and visual acuity (Early Treatment Diabetic Retinopathy Study eye chart). RESULTS: Forty-four percent (148/335) of women incorrectly placed one or both medications. Each vision measure was positively associated with Pillbox Ratio scores and varied with cognition and time to completion. Better visual acuity, contrast sensitivity, and stereopsis were each associated with better performance in women with poor cognition who filled the pillbox quickly. Additionally, better visual acuity was associated with better performance in participants with good cognition who filled the pillbox slowly; better stereopsis was associated with better performance in participants with poor cognition who filled the pillbox slowly and whose stereoacuity was below normal. CONCLUSION: Visual acuity, contrast sensitivity, and stereopsis should be considered potential risk factors for impaired ability to implement a medication regimen in older adults. Future research should investigate the role of vision, including contrast sensitivity and stereopsis, on performance of other instrumental activities of daily living.

Aged↗

PubMed2005

Predicting reading fluency in patients with macular disease.

PURPOSE: Difficulty in reading is the most frequent complaint of patients with macular disease (MD). This article assesses whether clinical variables measured at the onset of MD can be used to predict patients' future reading ability. METHODS: Twenty-five patients with MD were recruited within 4 weeks of the onset of symptoms in their second affected eye. Clinical and demographic features were recorded at baseline and at the exit point of the study 3 to 12 months later. Odds ratios (OR's) were constructed to assess the predictive value of these variables in terms of reading fluency and any change in reading speed at the exit point of the study. RESULTS: Baseline contrast sensitivity was associated with future fluent reading (OR, 2.40; interval size, 0.15; 95% confidence interval, 1.13 to 5.07). Age, sex, scotoma size, disease type, visual acuity, and reading speed were not statistically significant predictors of future fluent reading. It was not possible to predict fully in which patients reading speed improved or deteriorated. CONCLUSIONS: Contrast sensitivity can predict the likelihood of future fluent reading in patients with MD. Baseline reading speed, visual acuity, age, disease type, and scotoma size are poor predictors of future reading performance.

Contrast Sensitivity↗

PubMed2004

Visual function and subjective perception of visual ability after macular hole surgery.

PURPOSE: To evaluate the functional and anatomical results of macular hole surgery and to explore its effect on patients' Health-Related Quality Of Life (HR-QOL) and to investigate the associations between self-reported HR-QOL and conventional measures of visual function. DESIGN: Case series. 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 30 patients before and 4 months after macular hole surgery. Preoperative, intraoperative, and postoperative clinical data were collected including visual acuity, contrast sensitivity, and metamorphopsia. Multi-item scales rating different aspects of HR-QOL were compared before and after surgery, and their correlation with traditional methods of outcome evaluation was analyzed. RESULTS: Macular hole closure was achieved in 26 patients (87%). Mean LogMAR visual acuity improved by 6 +/- 10 letters for distance and 7 +/- 12 letters for near. Metamorphopsia was reduced by a mean of 35 +/- 70 squares on Amsler chart, and Pelli-Robson contrast sensitivity decreased by a mean of -0.09 +/- 0.3 log units postoperatively. The VFQ-25 composite score as well as scale scores associated with general vision, near vision, vision-related mental health, and role difficulties were significantly improved (P < .05) after successful closure of macular hole. Conversely out of the eight SF-36 health concepts, limitation in usual role activities because of emotional problems was the only one that significantly improved postoperatively. Both baseline and postoperative best-corrected visual acuity significantly correlated with most of the VFQ subscale scores before and after surgery, respectively. CONCLUSIONS: In this case-series, macular hole surgery appears to have a beneficial effect on patients' subjective perception of visual function. The use of vision-targeted health status questionnaires in conjunction with detailed clinical examination provides a more comprehensive overview of individuals' daily well-being after surgical intervention. Further controlled studies are required to confirm our findings.

Aged↗

PubMed2004

Fixation stability using central and pericentral fixation targets in patients with age-related macular degeneration.

PURPOSE: To determine fixation stability for central and pericentral fixation targets in patients with age-related macular degeneration (AMD). DESIGN: Comparative study. PARTICIPANTS: Twelve patients having late-stage AMD involving the fovea and 10 age-matched controls having no other eye diseases and visual acuity better than 20/25. METHODS: Six different fixation targets (1 degrees cross; 1 degrees filled circle; 1 degrees letter x; small 4-point diamond; large 4-point diamond using dimensions as in a field analyzer; large-crossover whole-image diagonal with open 1 degrees center) were presented on a high-resolution monitor. Before examination, subjects were given verbal instructions to move their eye to see the center of the target best. Fixation stability was measured for the preferred eye, with the fellow eye occluded, using a gaze tracker. Fixation stability was quantified by calculating the bivariate contour ellipse area (BCEA) over 30 seconds for each target. For statistical analysis, BCEA values (minutes of arc2) were converted into their logarithms. The absolute retinal scotoma for the study eye was determined using a scanning laser ophthalmoscope. MAIN OUTCOME MEASURE: Bivariate contour ellipse area. RESULTS: Visual acuity in patients (age range, 57-87 years) ranged from 20/32 to 20/600. The lowest BCEA values were found for the 1 degrees letter x in patients (mean, 12052.2%+/-254.0%) and for the 1 degrees cross in normal subjects (mean, 1286.9%+/-47.8%); the highest BCEA values were found for the small 4-point diamond in patients (mean, 23109.5%+/-298.3%) and for the large 4-point diamond in normals (age range, 62-79 years) (mean, 3229.2%+/-105.4%). The difference between the targets was significant for normal subjects (analysis of variance [ANOVA], P<0.01) but not for patients (ANOVA, P>0.05). In normals, BCEA values were significantly lower for central fixation targets than for pericentral fixation targets (P<0.01). CONCLUSION: Fixation is significantly less stable for pericentral fixation targets in normal subjects, indicating an advantage for central fixation targets. These results are particularly significant for any clinical and experimental testing method that requires the patient to maintain stable fixation.

Aged↗

PubMed2004

Association of visual field loss and mobility performance in older adults: Salisbury Eye Evaluation Study.

PURPOSE: To determine the association between visual field loss and orientation and mobility (O&M) performance in a population-based sample of older adults and to identify the specific regions of the visual field that are most strongly associated with O&M performance. METHODS: A population-based sample of 1504 persons between the ages of 72 to 92 was enrolled in the third round of Salisbury Eye Evaluation. Monocular visual fields (60 degrees radius) were tested with the 81-point, single intensity (24 dB) screening test strategy on the Humphrey Field Analyzer. Binocular visual fields were estimated from a combination of the monocular fields. The number of points missed was calculated for the overall visual field and for 3 non-overlapping regions: central (< or = 20 degrees radius), upper- and lower-peripheral visual fields. Orientation and mobility performance was evaluated by walking speed, number of bumps, and number of orientation errors on a circuitous, 32.8-m course seeded with obstacles. Log-linear regressions and linear regressions, adjusting for age, gender, body mass, height, cognitive and general health status, were performed. RESULTS: Loss in the overall visual field was associated with an increase in the number of bumps and decrease in walking speed. Visual field loss was not associated with the number of orientation errors. Out of the three visual field sub-regions that we tested, in terms of percentage of loss, the central and lower peripheral regions showed comparable decrements in walking speed and the central region was most strongly associated with number of bumps. CONCLUSIONS: The loss in visual field, which occurs with aging, is associated with a decline in mobility performance. Walking speed decreases, and the number of bumps into obstacles increases, with decreases in the visual field. The number of orientation errors is not associated with the loss in visual field that occurs with aging.

Aged↗

PubMed2004

Clinical performance of electronic, head-mounted, low-vision devices.

This study compared four electronic head-mounted devices (HMDs) (Jordy, Flipperport, Maxport and NuVision) with conventional optical low-vision aids (LVAs). The aim was to determine any performance differences for laboratory-based clinical measurements and practical visual tasks for patients with macular disease. Possible factors influencing success were explored. Ten patients with early onset macular disease (EOMD) and 10 with age-related macular disease (AMD) used the four HMDs, habitual spectacles and previously prescribed optical LVAs to complete a range of clinical measurements and everyday visual tasks. The clinical measurements were distance, intermediate and near acuities, and contrast sensitivity. The visual tasks were to read text of three sizes, to write a cheque and to identify grocery items on a shelf. Following the initial evaluation, each subject took home two randomly selected HMD devices for 2 weeks, after which performance measures were repeated. No single HMD stood out as being superior overall. Flipperport and Jordy provided significantly better distance and intermediate acuity than the previously prescribed optical LVAs but near acuity and contrast sensitivity were not consistently better with any of the HMDs. Practice at home provided some improvement in performance with HMDs, nevertheless, optical aids remained the best devices for optimum functioning for the majority of tasks. Younger patients and those with better distance acuity were more likely to benefit from HMDs, particularly when reading small print. In low vision clinics, practitioners should continue to show patients conventional optical aids and demonstrate these electronic HMDs only when appropriate for the individual patient.

Adult↗

PubMed2004

Fixation stability and reading speed in patients with newly developed macular disease.

BACKGROUND: Patients with macular disease and central scotomas must use a peripheral, preferred retinal locus (PRL) in place of their damaged fovea. This paper investigates the development of the PRL, with particular reference to the stability of fixation. METHODS: Twenty-five patients with age-related and juvenile macular disease were recruited. All patients had developed a scotoma in their better eye within the previous 2 weeks. Patients were assessed using a scanning laser ophthalmoscope and an infra-red gazetracker on four further occasions over the next 12 months. RESULTS: A linear relationship exists between reading speed and fixation stability for patients and control subjects. Fixation stability was not related to scotoma size, visual acuity or contrast sensitivity. Changes in fixation stability account for 54% of the variance in change in reading speed over the course of this study. CONCLUSIONS: The deficit in reading speed in patients with macular disease can be partially attributed to impairments in fixation stability.

Aged↗

PubMed2004

Divided visual attention as a predictor of bumping while walking: the Salisbury Eye Evaluation.

PURPOSE: The purpose of this study was to determine the association between bumping while walking and divided visual attention, as measured by the useful field of view (UFOV). METHODS: The Salisbury Eye Evaluation is a population-based study of community-dwelling adults, aged 72 to 92 at the third round of data collection. Participants walked a circuitous 32.8-m course, seeded with obstacles, and the number of bumps made while traversing the course was counted. UFOV divided attention score was based on processing speed: the time taken to identify a central target, and the location of a peripheral target simultaneously. Association between number of bumps and UFOV score was assessed in a generalized linear model, with adjustment for vision and attention measures that might explain the UFOV score. RESULTS: Of the 1504 participants in this study, 10.1% did not attempt the mobility course. In a model adjusting for demographic, physical, cognitive and attention, and vision measures, a decrease of 50 ms in processing speed for the divided-attention task was associated with a 4.9% increase (P = 0.004) in number of bumps made over the course. Receiver operating characteristic curves were created for the UFOV and visual field tests, to determine accuracy in detecting those with a high number of bumps. The visual field test had slightly higher area under the curve, but positive predictive value for both tests was low. CONCLUSIONS: The UFOV test of divided attention, as measured by processing speed, independently predicted bumping while walking. These data suggest that poor visual attention is a significant risk factor for bumping while walking.

Aged↗

PubMed2003

Visual acuity and contrast sensitivity in patients with neovascular age-related macular degeneration. Results from the Radiation Therapy for Age-Related Macular Degeneration (RAD-) Study.

BACKGROUND: Patients with advanced age-related macular degeneration (AMD) suffer not only from impairment in central visual acuity (VA), but also from reduction in contrast sensitivity (CS). We examined VA and CS changes over time in patients with subfoveal choroidal neovascularizations (CNV) as well as the correlation between the two parameters. METHODS: VA was determined according to a standardized protocol with the Early Treatment Diabetic Retinopathy (ETDRS) chart. CS was measured with Pelli-Robson charts. The angiographic characteristics of CNV and the presence of CNV in the fellow eye as well as gender and age were evaluated as possible prognostic factors of VA and CS progression. Two hundred and five patients with neovascular AMD were recruited within the Radiation Therapy for Age-Related Macular Degeneration (RAD) Study and were reviewed over 2 years. The treatment and control groups showed no significant difference for VA or for CS ( P>0.05), and both groups were considered together. RESULTS: At baseline, mean VA was 55.6+/-14.5 SD letters (EDTRS chart), and mean CS was 22.8+/-6.9 letters (Pelli-Robson chart). Spearman Correlation Coefficient ( r(s)) between VA and CS was r(s)=0.60, P=0.0001. Over 2 years the mean VA loss was 23.6+/-21.4 letters and mean CS reduction was 9.0+/-9.7 letters. Agreement between change of VA and change of CS was moderate ( r(s)=0.65, P=0.0001; kappa coefficient (grouped into VA loss < or =15, >15, >30 letters; CS loss < or =6, >6, >15 letters) kappa=0.43, 95% CI [0.32;0.54]). Proportional hazard models did not show any apparent influence of type of CNV, or CNV in the fellow eye, on change in VA and CS. CONCLUSION: The results indicate that VA and CS do not always show the same progression in visual function loss although they show a moderate correlation in eyes with neovascular AMD. Both parameters provide important information about visual disability and should be evaluated as outcome in interventional studies.

Aged↗