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At least 559 records · Page 31Linked to original sources
PubMed1996

Spatial frequency sweep pattern reversal VER acuity vs Snellen visual acuity: effect of optical defocus.

The effect of artificially induced image defocusing on visual acuities (VAs) measured by spatial frequency sweep pattern reversal visual evoked response (SPVER) and Snellen measurement was studied in six normal subjects. The steady-state SPVER was recorded using vertical gratings of 10 different spatial frequencies ranging from 0.52 to 30.36 c/deg. The SPVER acuity was compared with Snellen acuity (SA) measured under the same conditions of optical defocus. With moderate defocusing [< + 1.0 diopter (D), VA > 20/40], the SPVER acuities were equal to or poorer than the SAs. With more defocus (> + 1.5 D, VA < 20/70), the SPVER acuities became better than the SAs. The discrepancies between the SA and SPVER acuities may be the result of the influence of the parafoveal area on the SPVER at lower visual acuity levels.

Adult↗
PubMed1991

Lymphocytic adenohypophysitis: an immunohistochemical study.

Lymphocytic adenohypophysitis is a rare inflammatory disorder of the anterior pituitary gland. In some cases, there is evidence of concurrent autoimmune disease. We present the case of a 39-year-old woman who developed visual disturbance during the early postpartum period. Magnetic resonance imaging revealed an intrasellar mass with suprasellar extension. Study of the tumor tissue showed diffuse infiltration of the entire pituitary gland by lymphocytes and plasma cells. Immunohistochemical examination revealed that the majority of the infiltrating lymphocytes were T cells that might have modulated the immunoreaction to the anterior pituitary gland. We suggest that the disorder is related to cell-mediated immunity as well as humoral immunity.

Adult↗
PubMed1993

Neuro-ophthalmology and psychiatry.

Neuro-ophthalmology and psychiatry interact over several issues. The neuro-ophthalmologist can confirm the suspicion of nonorganic visual dysfunction by demonstrating the functional integrity of the visual system and the nonphysiologic nature of the visual complaints. He or she may recognize evidence of organic dysfunction in the patient with a presumed psychiatric diagnosis. In some cases, the pathology may be related to the use of certain psychiatric medications. Specialized examination techniques within the realm of neuro-ophthalmology may provide subtle information about the functional integrity of the central nervous system in patients with psychiatric disease. Clinical and investigational collaboration between the neuro-ophthalmologist and the psychiatrist will provide the most appropriate patient management and may further our understanding of the biological basis of psychiatry.

Brain Diseases↗
PubMed1990

Visual deficits related to dopamine deficiency in experimental animals and Parkinson's disease patients.

In patients affected by Parkinson's disease, and in the monkey model of this disease, visual defects have been shown using psychophysical and electrophysiological measures of spatial and temporal contrast sensitivity. These studies imply an essential role for dopamine in primate vision. There is electrophysiological and neurochemical evidence to suggest that at least part of the problem is impaired retinal processing caused by systemic dopaminergic deficiency. Some of the deficits that have been demonstrated, consistent with physiological studies, suggest that center-surround interaction of neurons may suffer as a consequence of dopaminergic deficiency. The role of the regulation of retinal dopamine (D1 and D2) receptors in primate vision and of the balance of these receptors in presynaptic dopaminergic deficiency is not yet determined. Using sinusoidal grating stimuli in cognitively loaded tasks may increase understanding of the behavioral consequences of visual deficits seen in dopamine deficiency syndromes.

Animals↗
PubMed1983

Clinical applications of preferential looking measures of visual acuity.

We have undertaken 3 lines of research aimed at the eventual transformation of the laboratory-based preferential looking (PL) acuity-testing procedures into clinically-useful techniques. (1) The first line of research involves studies of the parameters of PL testing, and the establishing of norms for various groups. The results show that acuity development is closely tied to gestational age, that infants' acuity is reduced at low luminances but does not vary significantly at levels above 1 log cd/m2, and that monocular acuity is poorer than previously-published binocular acuity norms. (2) The second line involves the development of a shortened procedure (the 'diagnostic grating' procedure) that maximizes the certainty of gaining the most critical information from an infant in a short time. In this procedure, the infant is tested with a low spatial frequency grating to screen for blindness or total lack of visual response, and another grating of a spatial frequency that is diagnostic of normal acuity for children of the patient's age. Based on the results with these two gratings and the time available, the child is then tested with other gratings to refine the acuity estimate. (3) The third line of research involves using the procedure, in a laboratory setting, with individual infants and children at risk for visual acuity deficits. Longitudinal case histories of patients with strabismus, ptosis, and suspected blindness are presented.

Amblyopia↗
PubMed1983

Visual testing with 'preferential looking' in mentally retarded children.

In 21 out of 26 children and young adults with mental retardation visual acuity could be successfully examined with operant preferential looking. There was a good correlation in this group of patients between ocular abnormalities demonstrated in an ophthalmological examination and the visual acuity results.

Adolescent↗
PubMedDate not supplied

The pattern electroretinogram: N95 amplitudes in normal subjects and optic neuritis patients.

Recent work has suggested that the N95 peak of the transient pattern electroretinogram (PERG) may be a more sensitive indicator of the late stages of retinal function prior to optic nerve activation than the P50 peak. In this report, we show that a new measure of N95 amplitude, based on digital filtering methods to identify a non-linear baseline before measurement, greatly reduced the amplitude variation in a population of 50 normal subjects when compared with two other plausible measures. We then used that new measure to follow the time course of N95 amplitudes in 12 optic neuritis patients. It was found that maintenance of a normal N95 amplitude at 6 months after onset of optic neuritis was always associated with excellent clinical recovery as measured by visual fields, acuity, presence or absence of an afferent pupil and optic atrophy, and contrast sensitivity (CS). Loss of N95 amplitude to below laboratory limits of normal was associated with abnormalities in these indicators of visual function. This study supports the idea that the N95 peak represents retinal ganglion cell function.

Adolescent↗
PubMed1992

Evaluation of the visual system in multiple sclerosis: a comparative study of diagnostic tests.

In 22 patients with clinically definite multiple sclerosis (MS) who were without visual symptoms and had a visual acuity of at least 1.0 in both eyes at the time of measurement, the following tests were performed to detect subclinical lesions in the visual system: visual evoked potential (VEP), contrast sensitivity test (CS), flight of colours test (FOC), colour vision test (Ishihara plates) (CV) and the pupillary light reflex (PLR). VEP was abnormal in 81.8%, CS in 72.7%, FOC in 36.4%, CV in 31.8%, and PLR in 52.3% of the patients. VEP and CS together were most sensitive: combining these techniques subclinical lesions of the visual system were detected in 90.9% (20/22) of these asymptomatic patients.

Adult↗
PubMed1985

Long-term auditory and visual complications of biotinidase deficiency.

The biochemical, dermatological and neurological motor disorders of biotinidase deficiency (multiple carboxylase deficiency) show a dramatic response to pharmacological doses of biotin. This condition is characterised by the accumulation of biocytin and depletion of biotin. Neuromuscular function returns to normal with the reversal of the characteristic organic acidaemia. It would appear that the optic and auditory nerves or their related neurological structures may suffer damage from the excess biocytin and deficient biotin. Despite reversal of the dermatological and psychomotor abnormalities children are likely to be left with auditory and/or visual handicaps if diagnosis and treatment is delayed beyond the first year of life. Treatment with biotin was commenced 6, 18, and 13 months after onset of symptoms. Two children subsequently were found to have visual impairment (acquired retinal dysplasia) and two had sensori-neural deafness. In one patient both defects were present.

Amidohydrolases↗
PubMed1996

Vision outcome at age 2 years in a low birth weight population.

We assess the prevalence of vision problems in a cohort of low birth weight infants at age 2 years and the relationship of these problems to neonatal brain injury. Data on prenatal and neonatal history and brain injury status were prospectively collected on 721 children weighing 500-2,000 gm at birth enrolled in a multi-center, population-based longitudinal study. Visual acuity was evaluated using the Teller Acuity Card Procedure. Abnormalities of the eye were assessed by a specially trained pediatric nurse practitioner. Failure of the acuity screen occurred in 62 of 699 tested (8.9%). Multiple logistic regression analysis revealed that the only significant independent predictors of failure included presence of disabling cerebral palsy (DCP) (odds ratio [OR] = 14.8) or nondisabling cerebral palsy (NDCP) (OR = 4.0) and Apgar score of less than 5 at 5 minutes (OR = 2.4). Parenchymal brain injury (PEL) was of borderline significance. Strabismus was present in 123 of 702 children (17.5%). Multiple logistic regression analysis disclosed that the joint predictors of strabismus were presence of DCP (OR = 7.2) and length of hospital stay (OR = 1.6). We conclude that low birth weight infants with parenchymal brain lesions leading to cerebral palsy are at particular risk for vision problems early in life and should be carefully evaluated.

Brain Injuries↗
PubMed2004

Learning effect among perimetric novices with screening C-20-1 frequency doubling technology perimetry.

PURPOSE: To investigate whether perimetric novices without glaucoma demonstrate a learning effect using screening-mode frequency doubling technology perimetry. DESIGN: Prospective observational study. METHODS: The study included 101 healthy subjects who had never undergone automated perimetry and who were administered the C-20-1 version of the frequency doubling technology. Subjects who returned an abnormal or unreliable test were retested until a normal result was obtained. RESULTS: Ninety-seven subjects (96%) returned a normal examination after one test, and 99 (98%) did so after two tests. Two subjects had abnormal initial tests, and two others had unreliable tests. These four subjects required repeat (up to four) testings to return a normal test. CONCLUSIONS: A small percentage of perimetric novices will demonstrate a learning effect using C-20-1 perimetry, but this mode has high specificity appropriate for glaucoma screening.

Adolescent↗
PubMed2004

Comparison of the amblyopia treatment study HOTV and electronic-early treatment of diabetic retinopathy study visual acuity protocols in children aged 5 to 12 years.

PURPOSE: To compare two established visual acuity protocols: the Amblyopia Treatment Study HOTV (ATS HOTV) visual acuity protocol and the Electronic-Early Treatment of Diabetic Retinopathy Study (E-ETDRS) protocol, in children aged 5 to 12 years. DESIGN: Prospective cohort study. METHODS: Crowded HOTV optotypes and crowded ETDRS optotypes were presented to 236 consecutive children aged 5 to 12 years using an electronic visual acuity tester (Palm handheld, personal computer, and monitor). Twenty-three percent of the children were classified as amblyopic, 35% as having uncorrected refractive error, 36% as normal, and 6% as other. Visual acuity test results were converted to logarithm of minimal angle of resolution (logMAR) units for analysis. RESULTS: In developmentally normal children (n = 230), testability was 100% for HOTV in 5- to 12-year-olds and 100% for E-ETDRS in 7- to 12-year-olds. The E-ETDRS testing could be completed in 52% of 5-year-olds and in 87% of 6-year-olds. Visual acuity performance was better when measured by HOTV compared with E-ETDRS (median difference 0.06 logMAR [three letters on a chart with five letters/line], P =.0001), and the difference was found in normal eyes, eyes with refractive error, and amblyopic eyes. CONCLUSIONS: The ATS HOTV protocol yields slightly better visual acuity performance compared with E-ETDRS in 5- to 12-year-olds, but on average by less than a logMAR level. This systematic difference is important when a physician changes testing modality as a child matures and should be considered when interpreting the results of recent and ongoing clinical trials in amblyopia.

Amblyopia↗
PubMed2004

Sensitivity and specificity of the 76-suprathreshold visual field test to detect eyes with visual field defect by Humphrey threshold testing in a population-based setting: the Thessaloniki eye study.

PURPOSE: To evaluate the screening performance of the 76-Suprathreshold (76-STHR) visual field test to detect eyes with visual field defect (VFD) as measured by Humphrey threshold testing in a population-based setting. DESIGN: Cross-sectional study. METHODS: All 88 subjects who agreed to participate in the pilot phase of the Thessaloniki Eye Study were included. Participants underwent a 76-STHR visual field test followed by a 30-full threshold (30-2 FTHR) test (Humphrey field analyzer). One eye/subject was randomly selected and included in the analysis. Sensitivity and specificity rates of the 76-STHR to detect eyes with VFD by the 30 to 2 FTHR test were calculated. RESULTS: When eyes with borderline results in the 30 to 2 FTHR test were classified as having a VFD, sensitivity rates of the 76-STHR to detect eyes with VFD by the 30 to 2 FTHR were 85.2%, 77.8%, and 74.1%, whereas specificity rates were 70%, 78%, and 86%, depending on the cutoff used for the 76-STHR. CONCLUSIONS: The 76-STHR test showed high sensitivity and low false-negative results at the "at least one point missed" cutoff level criterion to detect eyes with visual field defect by Humphrey threshold testing in a population-based setting. This criterion should be used when screening in a population-based study setting. By contrast, the 76-STHR would not be the appropriate screening test in a primary care setting with limited resources.

Aged↗
PubMed2004

Functional visual outcomes of cataract extraction in monocular versus binocular patients.

PURPOSE: To determine the change in functional vision that occurs with cataract surgery in a group of monocular patients compared with a group of binocularly sighted control subjects. DESIGN: A retrospective case-control study. METHODS: Study subjects comprised 100 functionally monocular patients who underwent cataract surgery at the Jules Stein Eye Institute between 1996 and 2002. Control subjects were 100 binocularly sighted patients, matched to study subjects by age, sex, and timing of surgery. A single ophthalmologist performed all of the operations using an ultrasonic phacoemulsification technique. Best-corrected visual acuity (BCVA) was measured before and after surgery using a conventional visual acuity monitor. Self-reported visual function was assessed before and after surgery using the Visual Function 14 (VF-14) questionnaire. Paired t tests were used to report statistical significance. RESULTS: The monocular group had significantly worse mean BCVA than the binocular group before and after surgery, but the improvement experienced by the two groups was statistically indistinguishable (P =.913). Mean global VF-14 score was significantly worse for the monocular than the binocular group before and after surgery, but the monocular group experienced a significantly greater improvement (P =.00164) in VF-14 following surgery (20.4 points for the monocular group vs 10.1 points for the binocular group). CONCLUSIONS: Monocular patients report twice as much improvement in functional vision as binocular patients despite similar BCVA gains. This may be because monocular patients had cataract surgery on their better-seeing eye, whereas binocular patients typically had surgery on their poorer-seeing eye.

Adult↗
PubMed2004

Development of an instrument to assess vision-related quality of life in young children.

PURPOSE: Quality of life (QOL) instruments are increasingly utilized in ophthalmological research. Measuring vision-related QOL in young children is complicated by constantly evolving abilities related to normal growth and development. Our aim was to develop vision-related QOL instruments for children in different age ranges <==7 years, and to provide initial validation of these instruments. DESIGN: Cross-sectional study. METHODS SETTING: Multicenter. PATIENTS: 773 pediatric patients (age <==7 years) with a wide range of ophthalmological diagnoses. PROCEDURE: Questionnaire. A 61-item prototype instrument with a wide variety of items was applied to 403 consecutive patients. The usefulness of items was evaluated as a function of age in order to derive two age-group specific instruments and to find the age limit dividing the age groups. Thus, age-specific versions of a Children's Visual Function Questionnaire (CVFQ) were defined for ages <3 years and >/=3 years, and applied to a convenience sample of patients. OUTCOME: Subscale scores. Factor analysis helped identify underlying dimensions of the data, and corresponding subscales were defined. Validation was provided by examining the internal consistency reliability and by exploring the associations between scores and clinical characteristics. RESULTS: Subscales for General health, General vision, Competence, Personality, Family impact, and Treatment were defined, with internal consistency reliabilities ranging from 0.60 to 0.86. The association between subscales scores and age was weak, whereas strong correlations were found with the level of visual impairment and type of visual diagnosis. CONCLUSION: The CVFQ assesses the impact of visual impairment on children and their families, and is expected to become a useful tool for the pediatric vision research community.

Child↗