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At least 433 records · Page 24Linked to original sources
PubMed1995

A comparison of driving in older subjects with and without age-related macular degeneration.

OBJECTIVE: To determine the effects of age and central vision loss on driving skills. METHODS: Ten subjects with age-related macular degeneration and average binocular visual acuity of 20/70, and 11 age-similar subjects with normal vision, were examined with a battery of cognitive and visual tests, an interactive driving simulator, and an on-road driving test. Data were collected on the frequency of real-world accidents and convictions for traffic violations. RESULTS: There were no significant differences between the two groups on any of the cognitive tests. The age-related macular degeneration group demonstrated poorer performance on the driving simulator, including delayed braking response times to stop signs, slower speeds, and more of both lane boundary crossings and simulator accidents. The age-related macular degeneration group also demonstrated poorer overall on-road test performance, including having significantly more points deducted for driving too slowly and for not maintaining proper lane position. However, these effects on the simulator and the on-road test did not translate into an increased risk of real-world accidents for the age-related macular degeneration group. Significantly more control subjects than patients with age-related macular degeneration were involved in self-reported accidents, and significantly more control subjects had state convictions for traffic violations. There was evidence of compensation in the age-related macular degeneration group in four major areas: (1) not driving in unfamiliar areas; (2) traveling at slow speeds; (3) self-restricting their nighttime driving, and (4) taking fewer risks while driving (eg, not changing lanes). There was also evidence of compensation in the older control group. CONCLUSIONS: Vision, simulator, and on-road test variables combined with subjective risk taking predicted self-reported real-world accidents in a logistic regression analysis. However, risk taking, rather than simulator or road-test performance, was the most significant predictor for both patients with age-related macular degeneration and the control group.

Accidents, Traffic↗
PubMed1996

Persistent palinopsia following ingestion of lysergic acid diethylamide (LSD).

OBJECTIVE: To identify a distinctive chronic visual complication of lysergic acid diethylamide (LSD) use. DESIGN: Description of the clinical findings in three patients with this disorder. SETTING: A neuro-ophthalmology referral center. RESULTS: All three patients experienced prolonged afterimages (palinopsia) during LSD intoxication and have continued to be symptomatic up to 3 years after they ceased to ingest the drug. Results of neuro-ophthalmologic and neurologic examinations and neuroimaging and electrophysiologic studies were normal. CONCLUSIONS: We have described three patients in whom persistent palinopsia developed following ingestion of LSD. Clinicians should inquire about past LSD use in all patients who initially have seemingly spontaneous, isolated palinopsia. Recognition of this distinctive clinical syndrome associated with LSD use might avoid unnecessary anxiety and excessive diagnostic tests for patients with this disorder.

Adolescent↗
PubMed1996

The association of postoperative subjective visual function with acuity, glare, and contrast sensitivity in patients with early cataract.

BACKGROUND: It has been shown in our previous studies that early cataracts affect vision in ways that can be measured by objective means and that this objective impairment in visual acuity, glare, and contrast sensitivity can be successfully reversed by cataract surgery. OBJECTIVE: To evaluate the association of subjective visual function with objective measures of acuity, glare, and contrast sensitivity in patients who were symptomatic from early cataract. METHODS: We administered a task-oriented questionnaire prior to and 4 months after cataract surgery to patients who were symptomatic from early cataract (median preoperative ETDRS [Early Treatment Diabetic Retinopathy Study] visual acuity of 20/40 [range, 20/20 to 20/80]); ETDRS visual acuity, disability glare, and contrast sensitivity were also measured at those times. RESULTS: Uncomplicated cataract surgery resulted in resolution or improvement of subjective symptoms for the great majority of subjects, and in a few subjects new symptoms developed or current symptoms worsened. We found a positive association between postoperative improvement in subjective visual function (as measured by the questionnaire) and postoperative improvement in objective visual function (as measured by visual acuity and contrast sensitivity). We also found that the greater the degree of preoperative impairment in objective visual function (as measured by visual acuity and contrast sensitivity), the greater the postoperative improvement in subjective visual function (as measured by the questionnaire). No such association was found for our disability glare test. CONCLUSIONS: Cataract surgery for symptomatic individuals with mild impairment in visual acuity does relieve visual symptoms, and preoperative measurement of contrast sensitivity can help determine who with early cataract is most likely to report subjective improvement in vision.

Adult↗
PubMed1996

Reduced stereoacuity in Williams syndrome.

Strabismus is a frequently recognized manifestation of Williams syndrome [Greenberg and Lewis, 1988: Ophthalmology 95:1608-1612; Kapp et al., 1995: Am J Ophthalmol 119:355-360]. We recently evaluated the ophthalmologic function of 12 patients with Williams syndrome (WS), with an emphasis on binocularity. Four of 12 patients (33%) had measurable strabismus. Of the 8 remaining patients, examination of binocular function was possible in 6, all of whom demonstrated reduced stereoacuity. We speculate that subnormal binocular vision and the poor visuospatial performance observed in patients with WS may be related to abnormal brain morphogenesis in the region of the occipitoparietal cortex.

Adolescent↗
PubMed2005

Screening for correctable visual acuity deficits in school-age children and adolescents.

BACKGROUND: Although the benefits of vision screening seem intuitive, the value of such programmes in junior and senior schools has been questioned. In addition to this there exists a lack of clarity regarding the optimum age, and frequency at which to carry out screening. OBJECTIVES: The objective of this review is to evaluate the effectiveness of vision screening programmes carried out in schools in reducing the prevalence of undetected, correctable visual acuity deficits due to refractive error in school-age children. SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Trials - CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) on The Cochrane Library (Issue 3 2004), MEDLINE (1966 to August 2004) and EMBASE (1980 to August 2004). No language or date restrictions were placed on these searches. To date it has not been possible to carry out any manual searches but it is hoped to include these in a future update. SELECTION CRITERIA: We planned to include randomised controlled trials including randomised cluster controlled trials. DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed study abstracts identified by the electronic searches. No trials were identified that met the inclusion criteria. MAIN RESULTS: As no trials were identified, no formal analysis was performed. A narrative synthesis of other retrieved studies was undertaken in order to explain current practice. AUTHORS' CONCLUSIONS: At present there are no robust trials available that allow the benefits of school vision screening to be measured. The disadvantage of attending school with a visual acuity deficit also needs to be quantified. The impact of a screening programme will depend on the geographical, and socio-economic setting in which it is conducted. There is therefore clearly a need for well planned randomised controlled trials, in various settings, to be undertaken so that the potential benefits and harms of vision screening can be measured.

Adolescent↗
PubMed2006

Quantifying axonal loss after optic neuritis with optical coherence tomography.

OBJECTIVE: To determine to what degree changes in retinal nerve fiber layer (RNFL) thickness after optic neuritis (ON) correlate with either visual recovery or impairment. METHODS: ON can cause visible defects within the RNFL, which can be quantified using optical coherence tomography (OCT). It may be possible to predict visual recovery by measuring RNFL loss after ON. Fifty-four patients underwent repeated evaluations with optical coherence tomography and standardized ophthalmic testing after ON. Regression analyses were used to determine the relationship between RNFL thickness and visual function. RESULTS: Thinning of the RNFL was seen in the majority of patients (74%), and it tended to occur within 3 to 6 months of ON. The average RNFL value was thinner (p<0.0001) in the affected (78 microm) compared with the unaffected eye (100 microm). Patients with incomplete visual recovery demonstrated greater RNFL loss after ON. Regression analyses demonstrated a threshold of RNFL thickness (75 microm), below which RNFL measurements predicted persistent visual dysfunction. INTERPRETATION: Determination of RNFL thickness may predict visual recovery after ON, and lower RNFL values correlate with impaired visual function. Optical coherence tomography may have a potential role as a surrogate marker for axonal integrity within the optic nerve among patients with ON.

Adolescent↗
PubMed1986

Creutzfeldt-Jakob disease: clinical analysis of a consecutive series of 230 neuropathologically verified cases.

In this consecutive series of 230 patients with neuropathologically verified Creutzfeldt-Jakob disease (CJD), the disease was found to affect men and women with approximately equal frequency in a peak plateau between the ages of 55 and 75 years (mean, 61.5 years). Familial cases accounted for 4 to 8% of the total series. Nonspecific prodromal symptoms occurred in one third of the patients, and the neurological presentation, although usually a gradually evolving mental deterioration, was of rapid onset in 20% of patients and in 36% of patients consisted exclusively of neurological symptoms. The great majority of these symptoms were of cerebellar or visual origin. Extrapyramidal muscular rigidity, myoclonus, and characteristic periodic electroencephalographic (EEG) complexes were observed comparatively late in the illness, and some type of involuntary movement or periodic EEG activity was seen in over 95% of the patients. The median duration of illness was 4 months (mean, 7.6 months); 90% of patients died within a year of onset.

Adult↗
PubMed1991

Visual dysfunction in Alzheimer's disease: relation to normal aging.

In patients with Alzheimer's disease (AD), compared with age-matched and young healthy control subjects, visual deficits in the following functions were observed: color, stereoacuity, contrast sensitivity, and backward masking (homogeneous and pattern). Critical flicker fusion thresholds were normal, relative to age-matched healthy subjects. For color, the majority of the errors were tritanomalous (blue axis). Color and stereoacuity deficits were unrelated to severity of dementia, in accordance with models of vision that describe these functions as modular rather than diffuse for cortical localization. Although contrast sensitivity was depressed throughout the frequency range in AD, more patients were impaired at low than at high spatial frequencies, contrasting with the observed normal aging pattern of high-frequency loss. Healthy elderly subjects showed depressed critical flicker fusion thresholds and reduced contrast sensitivity at high frequencies, relative to the young group; differences between these groups were not found for the other vision tests. A subset of the AD group received detailed neuro-ophthalmological examination, and no abnormalities were found. This finding, taken together with normal thresholds for critical flicker fusion, suggests that the widespread visual dysfunction reported here is more likely to be related to known pathological changes in primary visual and association cortex in AD than to changes in the retina or optic nerve.

Adolescent↗
PubMed1985

Eye-contact graphs.

The structure of nonverbal communication expressed as eye-contact between two human beings is analyzed using graph-theoretic tools involving a theorem of König on bipartite graphs and various results concerning directed graphs (as in Harary). A taxonomy for possible eye-contact configurations is constructed; then a theory, formed from a sequence of theorems proved about classes of eye-contact graphs derived from the taxonomy, is interpreted to analyze possible levels of communication. This theory can apply to any living system but it is interpreted here with respect to human subsystems composed of (1) individuals with normal vision, and (2) individuals with vision disorders which lead to crossed eyes.

Esotropia↗
PubMed2005

Multiple sensitive periods in human visual development: evidence from visually deprived children.

Psychophysical studies of children deprived of early visual experience by dense cataracts indicate that there are multiple sensitive periods during which experience can influence visual development. We note three sensitive periods within acuity, each with different developmental time courses: the period of visually-driven normal development, the sensitive period for damage, and the sensitive period for recovery. Moreover, there are different sensitive periods for different aspects of vision. Relative to the period of visually driven normal development, the sensitive period for damage is surprisingly long for acuity, peripheral vision, and asymmetry of optokinetic nystagmus, but surprisingly short for global motion. A comparison of results from unilaterally versus bilaterally deprived children provides insights into the complex nature of interactions between the eyes during normal visual development.

Adolescent↗
PubMed2005

Visual system side effects caused by parasympathetic dysfunction after botulinum toxin type B injections.

Botulinum toxin type B (BTX-B) has been approved by the Food and Drug Administration for the treatment of cervical dystonia. However, as with botulinum toxin type A (BTX-A) it has off-label uses, such as for hyperhidrosis, focal dystonias, spasticity, and facial wrinkles. BTX-B has also been shown to be a safe and effective alternative for patients who are resistant to BTX-A. The most commonly reported side effects include dry mouth and dysphagia. To date, there have been few reports of visual disturbances associated with BTX-B use. In this study, we report on three individual patients who received BTX-B and who subsequently developed parasympathetic dysfunction of the visual system after injections of BTX-B at remote sites.

Adult↗
PubMed1997

Identification of a gene within the tandem array of red and green color pigment genes.

The tandem array of color pigment genes on chromosome Xq28 contains nested exons of a distinct gene. This gene (termed TEX28) is composed of five exons that span almost the entire distance between the protein-coding regions of the color pigment genes and a transketolase-related gene. Although most of the TEX28 gene is repeated within the color pigment gene array, the exclusion of exon 1 from the array is predicted to restrict transcription to a single copy of the gene. The TEX28 gene encodes a polypeptide of 410 amino acid residues. This polypeptide does not display significant homology with any known proteins in public databases. Transcripts of the gene (1.8 kb) were detected in testes, but not in any other tissue examined. Color vision disorders that result from the deletion of color pigment genes should be reappraised for associated phenotypes that may derive from disruption of the TEX28 gene.

Amino Acid Sequence↗
PubMed2002

Mouse models to study GCAP functions in intact photoreceptors.

In photoreceptor cells cGMP is the second messenger that transduces light into an electrical response. Regulation of cGMP synthesis by Ca2+ is one of the key mechanisms by which Ca2+ exerts negative feedback to the phototransduction cascade in the process of light adaptation. This Ca2+ feedback to retinal guanylyl cyclases (Ret-GCs) is conferred by the guanylate cyclase-activating proteins (GCAPs). Mutations in GCAP1 that disrupt the Ca2+ regulation of Ret-GCs in vitro have been associated with severe human vision disorders. This chapter focuses on recent data obtained from biochemical and electrophysiological studies of GCAP1/GCAP2 knockout mice and other GCAP transgenic mice, addressing: 1. the quantitative aspects of the Ca2+-feedback to Ret-GCs in regulating the light sensitivity and adaptation in intact rods; 2. functional differences between GCAP1 and GCAP2 in intact rod photoreceptors; and 3. whether GCAP mutants with impaired Ca2+ binding lead to retinal disease in vivo by constitutive activation of Ret-GCs and elevation of intracellular cGMP, as predicted from in vitro studies.

Animals↗