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PubMed2006

Utility of the National Eye Institute VFQ-25 questionnaire in a heterogeneous group of multiple sclerosis patients.

PURPOSE: To investigate the utility of the 25-Item National Eye Institute Visual Function Questionnaire (VFQ-25) in assessing visual function in a heterogeneous group of multiple sclerosis (MS) patients and to identify correlations of VFQ-25 scores with clinically relevant objective visual parameters. DESIGN: Comparative cohort study. METHODS: The VFQ-25 was distributed to 34 patients with clinically definite MS. Patients underwent a comprehensive ophthalmic examination, including Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity (V(A)), Pelli-Robson contrast sensitivity (CS), Humphrey visual field 30 to 2 (HVF), and Farnsworth-Munsell 100-Hue color vision (100-Hue). Expanded Disability Status Scores (EDSS) were recorded for each patient. Comparative analyses using chi2 tests and t tests were performed. Spearman rank correlation coefficients were computed to identify relationships between VFQ-25 scores and the aforementioned visual parameters. RESULTS: In comparison with a published reference group without ocular disease, MS patients had considerably worse VFQ-25 composite scores (P < .01), being similar to published cohorts of glaucoma and cataract patients. VFQ-25 composite scores were found to be modestly and significantly correlated with several clinical parameters, including: V(A) (r = -0.63, P < .001), CS (r = 0.60, P < .001), HVF (r = 0.53, P = .003), and 100-Hue (r = -0.48, P = .01). EDSS scores, the use of disease modifying agents, and having a history of previous optic neuritis did not correlate significantly with VFQ-25 composite scores. CONCLUSIONS: The VFQ-25 questionnaire is a sensitive and useful tool in assessing visual function in MS patients. Such patients have quality of life indices similar to glaucoma and cataract patients, underscoring the significance of visual symptoms in MS.

Adult↗

PubMed1989

Psychophysical changes in glaucoma.

Chronic glaucoma has been thought to spare the central vision until quite late in the disease process. This assumption is based on the use of the relatively insensitive Snellen chart to measure central vision and the relatively sensitive kinetic and static perimetry to measure the peripheral vision. In recent years, new measures of visual function have been utilized to assess patients with glaucomatous damage. Sensitive methods of measuring central visual function such as color vision, contrast sensitivity (both spatial and temporal), and macular light sensitivity have demonstrated defects early in the glaucomatous process - sometimes even before perimetry is affected. Since these visual functions are largely mediated by macular fibers, central vision may be affected earlier and more frequently in glaucoma than previously believed. Studies of both the nerve fiber layer of the retina and of quantitative light sense perimetry suggest that glaucomatous damage may occur diffusely across the population of nerve fibers, focally in the arcuate portion of the nerve fiber layer, or in both places. Color vision, contrast sensitivity and macular light sense appear to correlate with the diffuse type of nerve fiber layer damage. The exact utility of the psychophysical tests that assess central visual function for the clinical management of glaucoma has not yet been demonstrated. More work is needed to determine which tests are most useful, what parameters are most efficient, and what the diagnostic and prognostic significance of abnormal values may be. However, the studies of color vision, contrast sensitivity and macular light sensitivity have led to a better understanding of how glaucoma affects visual function.

Color Perception↗

PubMed1982

Contrast sensitivity function and visual acuity of the opossum.

The Modulation Transfer Function (MTF) of the visual system of the opossum, D. marsupialis aurita, was determined using the amplitude of Visually Evoked Cortical Potentials (VECP) as response indicator. Stimuli consisted of a 180 degrees phase reversal of sinusoidally modulated gratings with an average luminance of 2.4 cd/m2. Contrast sensitivity was determined for various spatial frequencies and the MTF was calculated by the least square fit of an exponential function. The average acuity value obtained was 1.25 c/deg. The Fourier transform of the MTF was considered an approximation of the Line Spread Function of the visual system. The lowest value observed was 14 min of arc. The visual acuity observed in the mesopic range was not altered when stimulus intensity was raised to photopic levels.

Animals↗

PubMedDate not supplied

Visual retinocortical function in dementia of the Alzheimer type.

BACKGROUND: Some histological investigations have reported anomalies in the primary visual pathways of individuals with dementia of the Alzheimer type (DAT), while others have suggested that these visual structures are spared by the disease process. OBJECTIVES: This study was conducted to address this issue of substantial controversy. We determined in vivo whether DAT alters the functioning of the primary visual pathways by evaluating pattern-reversal electroretinograms (ERGs) and cortical visual evoked potentials (VEPs). METHODS: Twenty-seven individuals with mild to moderate DAT and 27 age- and sex-matched control subjects were included in the investigation. ERG and VEP recordings were obtained from all participants with the use of a clinical electrodiagnostic system. Stimulus conditions were biased towards a preferential response from the magnocellular and parvocellular subdivisions of the visual system. RESULTS: Amplitude and latency of the ERG were not affected by DAT. The VEP amplitude was not attenuated in DAT individuals, but there was a delay in the latency of the VEPs arising from both magnocellular and parvocellular streams of visual processing. CONCLUSION: Our results indicate that while the inner retina appears to be spared by the disease process, the visual function is altered upstream in the retinocortical visual pathways of individuals with DAT.

Aged↗

PubMed2006

Recovery of visual and functional disability following cataract surgery in older people: Sunderland Cataract Study.

PURPOSE: To examine changes in visual, psychological, and functional disability in older people waiting for cataract extraction and 6 months after surgery. SETTING: Community-based study in Northeast England. METHODS: Participants were 92 patients (mean age 78.1 years +/- 6.5 [SD], 79% female) with age-related cataract. Questionnaires were administered at time of listing for cataract extraction, 2 weeks preoperatively, and 2 and 6 months after surgery to assess visual symptoms and function, anxiety and depression, perceived health status, cognition, and activities of daily living. RESULTS: Mean waiting time was 265 +/- 64.4 days. Forty-six patients had first-eye surgery, 39 had second-eye surgery, and 7 had sequential-eye surgery (both eyes operated on during follow-up). During the waiting period, there were no significant changes in visual symptoms, cognition, or functional abilities. However, perceived health status, anxiety, and depression improved significantly during this time. For first- and second-eye patients, surgery resulted in significant improvements in all questionnaire scores, except activities of daily living. CONCLUSIONS: Despite waiting 9 months for cataract surgery, patients did not decline in visual symptoms, social functioning, or cognition. In first- and second-eye patients, successful cataract extraction resulted in significant gains in visual function, cognition, and emotional and general well-being. The benefits of cataract surgery in older people extended beyond simple measures of visual acuity.

Activities of Daily Living↗

PubMed2006

Differential impact of executive function on visual memory tasks.

Despite their common use in neuropsychological evaluation, little is known about the differential contribution of executive functioning to visual memory tests. In this study, hierarchical regression was used to determine the role of executive functioning on the Visual Reproduction subtest of the Wechsler Memory Scale--Third Edition, and the Rey-Osterrieth Complex Figure (ROCF) in a mixed neurological sample of 193 patients. Executive functioning was predictive of Visual Reproduction but not ROCF recall variables after accounting for demographic variables and global cognitive functioning. Only executive tests with a visuospatial component, the Trail-Making Test Part B and Wisconsin Card Sorting Test perseverative responses, were predictive of recall of Visual Reproduction stimuli. Organization of the ROCF was predictive of both Visual Reproduction and ROCF recall. These findings increase our understanding of the executive contribution to two common visual memory tests and may aid in the clinical interpretation of seemingly discrepant visual memory performance.

Adult↗

PubMed1996

Role of ocular involvement in the prediction of visual development and clinical prognosis in Aicardi syndrome.

AIMS/BACKGROUND: This study was undertaken to document visual function and acuity in patients with Aicardi syndrome, and to determine whether there is any relation between ocular features of the syndrome exhibited at birth and later visual function. METHODS: Fourteen patients with Aicardi syndrome, all examined and followed by the same ophthalmologist, were reviewed between 1975 and 1992 and their ocular characteristics and visual acuity described. It was hypothesised that larger lacunae may be associated with poorer clinical outcome and therefore the relation between these two variables was investigated. RESULTS: Visual acuity as documented by Snellen, Sheridan-Gardner, preferential looking, or pattern visual evoked potential tests was in the normal to low normal range in six eyes of four patients. Visual function correlated significantly with macular appearance. Good visual function was preserved if the fovea appeared normal on funduscopic examination and was uninvolved by lacunae. The size of the largest chorioretinal lacuna also correlated significantly with clinical outcome: patients with large lacunae were more likely to be immobile and to have no language skills. CONCLUSION: It was concluded that good visual function in patients with Aicardi syndrome may be anticipated if the fovea is normal. Although many patients have severe psychomotor retardation, the presence of predominantly small chorioretinal lacunae may indicate a better prognosis for mobility and language development.

Abnormalities, Multiple↗

PubMed1996

Remote clinic/patient monitoring for multicenter trials. Optic Neuritis Study Group.

Clinic monitoring is essential for the quality control of multicenter clinical trials. In studies of eye diseases, certification of visual function testers is integral to such monitoring. Routine site visits, while useful for evaluating clinic performance and certifying visual function testers, are expensive and not suitable for every study. As part of the Longitudinal Optic Neuritis Study (LONS), a follow-up study of the patients entered into the Optic Neuritis Treatment Trial (ONTT), we established a central system for clinic monitoring and visual function tester certification in lieu of performing site visits. We also established a centralized and well-defined system for maintaining patient contact in an attempt to enhance follow-up visit compliance. Both have been used over the first three years of the LONS. Coordinators at two of the participating clinical centers were selected to serve as regional coordinators; each was responsible for overseeing seven or eight clinics and 200 patients. Annually by phone these coordinators perform certification of each technician's visual function testing. Clinic monitoring is performed by monthly phone calls. Conference calls involving each clinic's personnel, the regional coordinator, and Data Coordinating Center personnel are held one or two times per year. Patient phone contact at four-month intervals between annual patient exams is done to evaluate visual and general health status, to review study information, and to coordinate and encourage annual protocol exams at the respective centers. This system has helped achieve a visit completion rate of over 90% for active study patients. Patient phone contact by the regional coordinators has been well received. Telephone certification of visual function technicians by the regional coordinators appears to be as effective as on-site certification. Clinic performance appears to be continuing at the same high level as during the period of annual site visits. Although site visits are valuable for clinical trials, if routine site visits are not feasible the methods we have implemented for remote monitoring may be useful.

Appointments and Schedules↗

PubMed1975

Functional asymmetries of the human visual system as revealed by binocular rivalry and binocular brightness matching.

Two techniques, a binocular rivalry task and a binocular brightness matching task, were designed to yield indices of asymmetry (relative dominance weights) for the two eyes, the crossed and uncrossed visual pathways, and the two cerebral hemispheres. Twenty subjects with normal vision were run on all conditions. Intercorrelations of the dominance weights obtained by the two methods showed no relationship between the two methods, but produced three hypotheses about visual functioning: (1) the left hemisphere appears more dominant for rivalry; (2) the right hemisphere appears more dominant for brightness matching; (3) the uncrossed visual pathways are dominant over the crossed pathways in the binocular rivalry task.

Dominance, Cerebral↗

PubMed1992

["Glare vision". I. Physiological principles of vision change with increased test field luminance].

Clinical tests of visual acuity are an important measure of visual function. However visual acuity is usually determined only in narrow range of luminance levels between 160 and 320 cd/m2; therefore losses of visual acuity in other ranges of light intensity can not be detected. In a distance of 80 cm from the patients eyes, Landolt rings of varying sizes were presented on a small test field whose light intensity can be varied between 0.1 and 30,000 cd/m2. Thereby an acuity-luminance-function can be obtained. We studied such functions under different conditions of exposure time both with constant and with increasing luminance of the test field. We found that persons with normal vision can increase their visual acuity with increasing test field luminance up to a range of 5000 cd/m2. The maximum values of visual acuity under optimal lightening conditions lie (varying with age) between 2.2 and 0.9. Under pathological conditions visual acuity falls at high luminances accompanied by sensations of glare. Tests of glare sensitivity as a function of exposure time showed 4 sec to be a critical time of exposure since after 4 sec normal persons just reach their maximum visual acuity at high luminances. The underlying physiological mechanisms lead us to suppose that patients with neuronal light adaptation disturbances display a greater visual loss as a result of decreased time of exposure than those with disturbances in the ocular media. Visual acuity as well as the capacity to increase the patients visual acuity under optimal conditions of lighting were both found to be strongly age-dependent.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

Vision change and quality of life in the elderly. Response to cataract surgery and treatment of other chronic ocular conditions.

OBJECTIVE: Evaluation of health care in older populations has increasingly focused on quality of life as a critical outcome of treatment. Vision is assumed to be central to functioning. Data suggest that aging, in itself, is associated with a decline in visual functioning, which, in turn, is related to a decline in physical and mental functioning. Other studies indicate that cataract surgery is followed by significant improvement in vision and visual function. Our objective was to test these assumptions. DESIGN: Prospective study of 1021 patients, consecutively drawn from 76 randomly selected ophthalmologists' offices in three cities. Structured interviews were completed at baseline, 2 months, and 1 year after entry. PATIENTS: Six hundred thirteen patients with cataracts and 408 other ophthalmic patients drawn from the same offices but treated for other chronic ocular disorders. All received refractive services as needed. SETTING: Patients from three cities (Baltimore, Md, St Louis, Mo, and San Diego, Calif) were interviewed once in their homes and twice by telephone. INTERVENTIONS: The study involved the measurement of the effects of usual treatment for cataracts and other degenerative eye diseases. MAJOR OUTCOME MEASURES: Visual, social, and psychological functioning. RESULTS: Within 1 year of treatment, change in visual function was accompanied by significant changes, in the same direction, in quality of life functions: night-time driving, daytime driving, community activities, home activities, mental health, and life satisfaction. In addition, the patients with cataracts showed significantly greater improvement in measures of vision than did the noncataract group. CONCLUSIONS: Regardless of treatment, improvement across quality of life functions occurred when visual function improved. Thus, many types of functional degeneration observed in older populations, attributed to a decline in vision, can be slowed, or even reversed, when visual function is improved. Cataract surgery was effective in improving vision and quality of life functions.

Aged↗

PubMed1979

Visual evoked potential (VEP): basic concepts and clinical applications.

The Visual Evoked Potential is the objective measurement of visual function monitored at the level of the occipital cortex with scalp electrodes. This article summarizes many of the recent clinical applications of the VEP. Included are basic concepts of the VEP and its clinical utilization for the objective assessment of refractive error, visual acuity, amblyopia, binocularity, demyelinating diseases, psychogenic disorders, pre-surgical prediction of post-surgical visual function, visual fields, color blindness and neurological development.

Amblyopia↗

PubMed2004

Disturbed visual system function in methionine synthase deficiency.

BACKGROUND: Isolated functional methionine synthase deficiency occurs in the cblE and cblG defects of methylcobalamin metabolism and is one of a number of causes of severely elevated plasma homocysteine. Clinical features are predominantly of a neurological nature but also include functional restriction of the visual system manifesting as loss of visual acuity and nystagmus. As yet, the origin and pathogenesis of impaired vision have not been explained. MATERIALS AND METHODS: We investigated a patient who was proven by complementation analysis in cultured fibroblasts to belong to the cblG complementation group. Ganzfeld electroretinograms (ERG) and flash visual evoked potentials (VEP) were recorded over a period of 4 years. RESULTS: Amplitudes of all International Society for Clinical Electrophysiology of Vision (ISCEV) standard responses were below normal. The greatest reductions were of rod response to 24 microV, of standard combined response (SC) b-wave to 120 microV, of oscillatory potentials (OP) to 5 microV, of cone response b-wave to 35 microV, and of 30 Hz flicker response to 8 microV. Except for SC and cone a-waves at age 2.5 and 3.5 years, as well as cone b-wave at 3.5 years, amplitudes remained at a subnormal level at follow-up examinations. Implicit times were slightly prolonged (SC b-wave 6 ms, OPs 2 ms, cone b-wave 2 ms, 30 Hz flicker 4 ms) or fell within the normal range. Responses of the flash VEP were severely deformed but reproducible. CONCLUSIONS: This is the first report of detailed investigations of the visual system in a patient with isolated methionine synthase deficiency. Reduced oscillatory potentials suggest microvascular damage to the retina through homocysteine. Decreased photoreceptor function as well as ganglion cell loss as indicated by pathological flash VEPs may reflect a cytotoxic impact of homocysteine on neurons of the visual pathway.

5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗

PubMed2004

Simultaneous bilateral cataract surgery: a retrospective survey.

PURPOSE: To evaluate patient satisfaction and functional visual outcome, safety, and visual and refractive outcomes of simultaneous bilateral cataract surgery (SBCS). SETTING: North Karelia Central Hospital, Joensuu, Finland. METHODS: A retrospective external review of 200 patients drawn randomly from 637 patients who underwent SBCS at the North Karelia Central Hospital in 2001 was performed. Of the 200 eligible patients, 141 who returned a completed questionnaire on patient satisfaction and functional visual outcome of SBCS were enrolled. Postoperative refraction and best corrected visual acuity (BCVA) were available in 148 eyes of 74 patients. RESULTS: The surgery was carried out under topical anesthesia, and 98% were outpatient surgeries. No serious intraoperative or postoperative complications occurred. Of the 141 patients, 96% (95% confidence interval [CI]: 91-98) experienced SBCS as positive or quite positive, 89% (95% CI: 83-94) felt safe to go home after the surgery, and 91% (95% CI: 85-95) would recommend SBCS to their relatives or friends. The mean visual functioning index (VF-7 score) was 87.3 (median 95). Postoperative BCVA was 20/40 or better in 84% (95% CI: 77-89) and 20/25 or better in 66% (95% CI: 57-73) of the 148 eyes examined. The postoperative refraction was +/-0.75 diopter (D) of the target value in 78% (95% CI: 71-85) and +/-1.5 D in 95% (95% CI: 91-98), and the mean anisometropia was 0.26 D (SD 0.6 D, range 0-1.65). CONCLUSION: This study provides evidence that SBCS by experienced surgeons is likely to be a safe and efficient procedure and is positively received by patients.

Adult↗

PubMed2003

Topical phenylephrine may result in worsening of visual loss when used to dilate pupils in patients with vaso-occlusive disease of the optic nerve.

Four patients (age range 54-82, 1F 3M) diagnosed with non-arteritic ischemic optic neuropathy experienced acute worsening of visual function after instillation of phenylephrine for dilated funduscopic examination. They experienced decreased visual function immediately or shortly after administration of topical mydriatic drops given in preparation for funduscopy. In all cases one drop each of 2.5% phenylephrine and 0.5-1% tropicamide was used. Three patients had classical risk factors such as hypertension, diabetes, and had a contralateral "disc-at-risk". The female and youngest patient had ischemic optic neuropathy presumed secondary to lupus erythematosus. The time from acute visual loss to presentation to neuro-ophthalmic care ranged from 1-6 days. The time of onset of the decline in visual function varied from 45 minutes (patient with lupus) to 12 hours after instillation of mydriatic drops. Visual acuity at diagnosis ranged from 20/40-20/400. Phenylephrine is a mydriatic with vasoconstrictive properties, which may be absorbed through the cornea, thus yielding non-negligible intraocular concentrations. Vasoconstriction of the watershed posterior ciliary capillary beds may result in further precipitating infarction of already compromised circulatory territories in edematous optic nerves. Because phenylephrine is a known vasoconstrictor in vivo and in vitro, it is more likely to cause deleterious vasoconstriction and an acute decline in visual function in patients with acute ischemic optic neuropathy than tropicamide. The routine practice of using phenylephrine to prepare patients for funduscopic assessment should be re-examined, particularly in patients with ischemic optic neuropathy.

Administration, Topical↗

PubMed2003

Differential effects of low-frequency rTMS at the occipital pole on visual-induced alpha desynchronization and visual-evoked potentials.

Visual-induced alpha desynchronization (VID) and visual-evoked potentials (VEPs) characterize occipital activation in response to visual stimulation but their exact relationship is unclear. Here, we tested the hypothesis that VID and VEPs reflect different aspects of cortical activation. For this purpose, we determined whether VID and VEPs are differentially modulated by low-frequency repetitive transcranial magnetic stimulation (rTMS) over the occipital pole. Scalp EEG responses to visual stimuli (flashed either to the left or to the right visual field) were recorded for 8 min in six healthy subjects (1) before, (2) immediately following, and (3) 20 min after left occipital rTMS (1 Hz, 10 min). The parameters aimed to reduce cortical excitability beyond the end of the TMS train. In addition, simple reaction times to visual stimulation were recorded (left or right hand in separate blocks). In all subjects, VID was significantly and prominently reduced by rTMS (P = 0.0001). In contrast, rTMS failed to modulate early VEP components (P1/N1). A moderate effect was found on a late VEP component close to manual response onset (P = 0.014) but this effect was in the opposite direction to the VID change. All changes were restricted to the targeted left occipital cortex. The effects were present only after right visual field stimulation when a right hand response was required, were associated with a behavioral effect, and had washed out 20 min after rTMS. We conclude that VID and early VEPs represent different aspects of cortical activation. The findings that rTMS did not change early VEPs and selectively affected VID and late VEPs in conditions where the visual input must be transferred intrahemispherically for visuomotor integration (right visual field/right hand) are suggestive of rTMS interference with higher-order visual functions beyond visual input. This is consistent with the idea that alpha desynchronization serves an integrative role through a corticocortical "gating function."

Adult↗

PubMed2004

Assessment of visual satisfaction and function after cataract surgery.

PURPOSE: To examine the relationships between importance, satisfaction, visual acuity, and visual function in a sample of preoperative cataract patients and to derive and prospectively evaluate a shortened measure of visual function. SETTING: Day-stay cataract surgery unit at large private hospital and consulting rooms of metropolitan ophthalmologists. METHODS: Two independent samples of 111 and 121 patients were surveyed before and after surgery with regard to their visual satisfaction, trouble with vision, VF-14 visual function, overall satisfaction, and importance of factors affecting patient satisfaction. A 7-item scale of visual function derived from the first sample's results was prospectively tested against the second sample. Distance and reading acuities were recorded from the patients' charts. RESULTS: The 7-item measure of visual function strongly correlated with the VF-14 (r>0.9) and had predictive power equal to that of the VF-14 for satisfaction and trouble with vision. However, the 7 items differed somewhat from a version developed in Helsinki. Distance visual acuity was not significantly correlated with visual function, satisfaction, or trouble with vision, although reading acuity was significantly correlated with visual function and trouble with vision (r=0.31 and r=0.32, respectively). CONCLUSIONS: A shortened measure of visual function that had a predictive value equal to that of the VF-14 can more practically be used in everyday practice. Furthermore, the study showed that regional factors matter and highlights the necessity of basing measurement scales on factors important to the population in question to ensure scale validity.

Aged↗

PubMed1997

Impact of cataract surgery on car driving: a population based study in Sweden.

AIMS: To investigate the outcome of cataract surgery on the patients' self estimation of visual function while driving. Furthermore, the benefit of surgery to the car driving population was determined. METHODS: A total of 208 consecutive patients (211 cases) with driving licences, who underwent cataract surgery with intraocular lenses, were studied prospectively using self administered questionnaires. Their self estimated degree of visual functional problems while driving were analysed before and after surgery. RESULTS: Visual problems while driving declined from 82% preoperatively to 5% after surgery. Remaining visual problems with the operated eye were present in only seven patients. Problems in estimating distance while driving decreased from 37% before surgery to 6% after surgery. Twenty three per cent of the patients drove with a visual acuity below the requirements for driving in Sweden before surgery and only 4% after surgery. There was no correlation between the degree of visual problems while driving and visual acuity before surgery. CONCLUSION: The car driving population greatly benefited from cataract surgery in terms of subjectively improved visual function and distance estimation while driving. Functional visual problems while driving should be considered as an indication for cataract surgery. These findings also indicated that the second eye should be operated on, if necessary, to achieve optimal ability to estimate distance and give best possible road safety.

Adult↗