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Results for “Visual function”

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At least 73 records · Page 4Linked to original sources

PubMed1989

Red glasses and visual function in retinitis pigmentosa.

UNLABELLED: As a consequence of animal reduction of the light regimes have been tried on patients with retinitis pigmentosa. The trials have been very limited and have not given reason for hope that such reduced light therapy may be beneficial. However, RP patients trying red glasses have reported acute subjective improvement of their visual function. It was the purpose of this study to try to document the reports more objectively. Five visual functions were tested with and without red glasses with the following results: 1. Visual acuity and contrast sensitivity. For one volunteer a small reproducible improvement was found. 2. Color vision. In most cases deterioration was found of already deficient color vision. 3. Visual fields. For volunteers with relatively preserved vision no difference or slight deterioration was found. For the other volunteers slight improvements were found. 4. Intraocular light scatter. No differences were found. 5. Dark adaptation. Improvements were found when the glasses were used as adaptation aid according to the method of Trendelenburg (rod function). For cone function no difference was found upon continuous wearing of red glasses. IN CONCLUSION: use of red glasses does not seem to be of great benefit as a rule. On the other hand, apart from the reduction in color discrimination no serious disadvantages seem to be inherent in their wear by RP patients.

Color↗

PubMed1988

Visual function and rhodopsin levels in humans with vitamin A deficiency.

Details of rod and cone dysfunction in vitamin A deficiency have been studied in two subjects with primary biliary cirrhosis and one with Crohn's disease, all of whom presented with symptoms of night blindness. Visual function in the mid-peripheral retina was monitored with two-color adaptometry and rhodopsin levels were measured by fundus reflectometry. Initially all three subjects had no measurable rod function and delayed cone adaptation. In one case the dark-adapted cone threshold was also elevated. Oral supplementation with vitamin A restored visual function to normal within 8 days in all subjects. During supplementation, cone function was restored more rapidly than that of rods, though the pattern of recovery was similar for each receptor type. Final thresholds improved first, though the rates at which they were reached were abnormally slow. As recovery continued, adaptation kinetics returned to normal. When rod adaptation was delayed, the regeneration of rhodopsin was also abnormally slow. When rod final threshold was 2 log units higher than normal, rhodopsin regeneration was incomplete, reaching about 70% of the normal level. The initial stages of visual dysfunction during onset of vitamin A deficiency were studied in one subject, and were found to mirror the pattern seen during recovery: rod adaptation was initially slower than normal, but reached completion. Cone adaptation remained normal until rod function was almost absent.

Adult↗

PubMed1990

Acuity card assessment of visual function in the cryotherapy for retinopathy of prematurity trial.

The primary outcome measure of the effectiveness of cryotherapy in the original design of the Multicenter Trial of Cryotherapy for Retinopathy of Prematurity (CRYO-ROP) was the anatomic status of the retina, as documented by fundus photography 3 months and 12 months after infants had received treatment. The authors describe the addition of a measurement of visual function, the Acuity Card procedure, to the CRYO-ROP study. After training, four visual-acuity testers attempted to measure monocular grating acuity in all randomized infants and approximately one fourth of the natural-history infants in the study, tested at 1 year postcryotherapy or 1 year postterm. In 95% of infants on whom testing was attempted, monocular acuity values from each eye were obtained. Interobserver test-retest results on 25 eyes of 13 randomized infants agreed to within one octave or better in all but one of the eyes. The high testability rate and good interobserver agreement suggest that the Acuity Card procedure has been a successful method of assessing visual function in the CRYO-ROP study.

Clinical Protocols↗

PubMed1992

[The properties of visual functions and familial analysis in blue cone monochromatism].

The diagnosis of blue cone monochromatism (BCM) is based on severely affected color vision with preserved blue function, nearly absent photopic ERG, and a family pedigree compatible with X-linked inheritance. In the past, there has been no familial report of BCM in Japan. We found a Japanese family with BCM and studied the ocular findings of three affected members and a female carrier. Two of three affected members showed unique properties of BCM in their visual functions, including color vision and ERG. One affected member, a brother of their mother (43 years old), showed achromatic color vision. He had diabetic retinopathy and moderate cataract, which, might have disturbed his preserved blue cone function, resulting in the achromatic vision. A female carrier showed normal visual function, except that her photopic ERG was slightly reduced in amplitude.

Adult↗

PubMed1979

Comparison of visual function studies in two cases of senile macular degeneration.

In this paper two relatively early cases of senile macular degeneration are compared by making use of a number of tests of visual function, some relatively new, coupled with observation of the fundus and analysis by fluorescein angiography. The functional tests include visual acuity, the sustainedlike and transientlike functions which are believed to test inner retinal receptive field properties and to have origin in the inner and outer plexiform layers, the Stiles-Crawford function which reflects the directional sensitivity and orientation of photoreceptors, and increment threshold curves. In one case there was evidence of inner retinal involvement at the time the tests were conducted, but, because the Stiles-Crawford function remained essentially normal, it is assumed that the receptors were not disturbed relative to their orientation. In this case (as in many others), the zone or area exhibiting functional change does not necessarily match the area exhibiting anatomical change as observed by examination of the fundus, fundus photography, and fluorescein angiography. In the second patient there is evidence of both anomalous inner retinal function and disturbance in receptor alignment. The later suggests disorientation of the receptor bed. These findings correlated with the fundus observation and fluorescein angiographic evidence of a leak, resulting in the presence of serous fluid beneath the neurosensory retina. With resolution of this fluid there was a return of the functional tests toward normal. At this time, it is not possible to determine whether, in two cases, the functional changes are proceeding on a parallel course, but are at different stages, or whether they are the expression of somewhat different anomalies.

Aged↗

PubMedDate not supplied

Visual functions following bilateral surgery of congenital cataracts in children.

The visual functions, before and after surgery, of 19 children with bilateral congenital cataract are evaluated. Some of the children, in spite of the poor vision before surgery and the late age at surgery, developed good vision with binocular functions. These children probably had an incomplete lens opacity in their early childhood which became completely opaque at an age at which irreversible stimulus deprivation amblyopia is unlikely to develop. Therefore, children over the age of 6 years with poor vision due to congenital cataract, on whom no information is available concerning the density of their lens opacities in early childhood, should not be regarded as having a poor visual prognosis.

Adolescent↗

PubMed1986

Visual function in the newborn infant: is it cortically mediated?

Reasonably normal visual behaviour was observed in premature infants in the neonatal period up to about 48 weeks' postmenstrual age even when there was gross destruction of the cortex in the occipital region. Symmetrical visual evoked responses could be elicited at this time even when asymmetrical lesions of the occipital cortex had been demonstrated on ultrasound scan; the visual evoked response became asymmetrical later, around the age of 2 months. A visual evoked response, albeit of abnormal waveform, was recorded in an infant with complete absence of the visual cortex. These findings suggest that early visual function, both behavioural and electrophysiological, is not dependent on the cortex but appears to be mediated through subcortical pathways.

Abnormalities, Multiple↗

PubMed1990

Self-reported visual function and academic success: Cattell revisited.

To test the hypothesis that visual deficits might hamper college students' academic success, we examined the relationship between a reliable self-report measure of visual function and semester grades. The correlation between the Everyday Vision Questionnaire scores and the grades of 331 college students was .01, which replicates and extends the historical findings of Cattell and others.

Achievement↗

PubMed1991

Optic nerve sheath decompression for nonarteritic ischemic optic neuropathy improves multiple visual function measurements.

Optic nerve sheath decompression was performed in seven patients with nonarteritic anterior ischemic optic neuropathy. Visual function was evaluated by measurement of visual acuity with standardized Early Treatment Diabetic Retinopathy Study charts, color vision testing, quantitation of relative afferent pupillary defects with neutral-density filters, and Goldmann and Humphrey perimetry. Visual acuity improved markedly in all patients (at least doubling of the visual angle); the peripheral visual field expanded by at least 20 degrees (as measured by Goldmann perimetry) in six patients. Three patients also experienced marked improvement in color vision, relative afferent pupillary defect, and foveal sensitivity. Our experience supports the possible beneficial effect of optic nerve sheath decompression in patients with nonarteritic anterior ischemic optic neuropathy.

Aged↗

PubMed1977

The effect of corneal edema on visual function.

Corneal edema was produced by atmospheric-induced anoxia and the visual effect was assesed by conventional acuity tests and compared with contrast sensitivity measurements. For the degree of edema which this technique produced, contrast sensitivity was depressed for only high spatial frequencies and could be considered in terms of equivalent defocus. This was not the case ofr a greater degree of edema which was simulated by a diffuser with a particle size that mimics the diffraction effects from an edematous cornea. Equivalent blur was not applicable, since low spatial frequencies were also affected and the letter and contrast sensitivity tests gave radically different results. In the light of these findings, the validity of the present letter acuity evaluation of visual function for patients in which intraocular scattering is involved is questioned.

Cornea↗

PubMed1989

Evaluation of the transcranial approach to pituitary adenomas based on quantitative analysis of pre- and postoperative visual function.

Over a 16-year period, 105 patients with pituitary adenoma accompanied by visual disturbance underwent transcranial intracapsular removal of the tumor followed by radiotherapy. Postoperative recovery of visual function in these patients was compared with the results obtained in other institutions after trans-sphenoidal surgery. The severity of preoperative visual impairment was correlated with the duration of visual impairment, the degree of optic atrophy, the extent of suprasellar tumor infiltration, and age. Trans-sphenoidal surgery appears more effective in patients with mild preoperative visual disturbance, whereas the transcranial approach yields better results in patients with moderate to severe preoperative visual deficits.

Adenoma↗

PubMed1992

[An analysis of the causes of glaucomatous visual function damage by computed multifactorial stepwise regression].

Computed multifactorial stepwise regression analysis of quantitative visual field deterioration in relation to 28 factors showed that only the hemorheological indices entered the multiplex regression equations, especially accurately for POAG patients with severe visual damages. Besides, the patients might also have lower antioxidant capability in the red cell membrane protein. Based on the present results and data abroad, POAG might pertain to the blood hyperviscosity syndrome, and with elevated intraocular pressure and decreased ocular arterial pressure, the visual function damage would be aggravated.

Blood Viscosity↗

PubMed1991

Visual function in Alzheimer's disease and normal aging.

We examined a wide range of visual behaviors in 59 patients with Alzheimer's disease (AD), 35 elderly control subjects, and 12 young control subjects. A subset of the patients with AD received neuro-ophthalmologic and electrophysiologic examinations in order to evaluate the integrity of the retino-calcarine pathway. Patients with AD showed significant, selective losses in visual function, including color discrimination, stereoacuity, contrast sensitivity, and backward masking, but not in critical flicker fusion. The deficits were not attributable to clinically apparent lesions of the retina or optic nerve. We therefore suggest that AD lesions in primary visual and posterior association cortices underlie the observed behavioral abnormalities.

Adolescent↗

PubMed1977

The effect of systemic hypotension during cardiopulmonary bypass on intraocular pressure and visual function in humans.

The effect of controlled systemic hypotension on intraocular pressure (IOP) and visual function was measured in a group of 12 patients undergoing extracorporeal perfusion during cardiovascular surgery. When venous pressure was controlled, intraocular pressure was noted to fall following a fall in the systemic blood pressure. There was a return of IOP toward normal levels with recovery of the systemic blood pressure. Systemic hypotension of 25 to 100 mm Hg for up to 201 minutes in the presence of hemodilution and hypothermia was not associated with any functional or morphologic change in ocular function.

Adult↗

PubMed1988

The outcome of visual function in capsular glaucoma.

In a retrospective study is found that 2.5% of subjects aged 70 years or more developed visual field defects due to capsular glaucoma within their lifetime. Before death 0.8% were amaurotic in one eye, and 0.3% had serious impaired visual function caused by bilateral capsular glaucoma. Advanced visual field defects present at diagnosis and central vein occlusion contributed to bad outcome. When glaucomatous disc cupping without visual field defects were present at diagnosis, 50% developed field defects during their lifetime. Of those with moderate visual field defects at diagnosis 59% advanced one or more stages.

Aged↗

PubMed1992

Optic nerve decompression surgery improves visual function in patients with pseudotumor cerebri.

Papilledema from pseudotumor cerebri can cause severe loss of visual acuity and visual field. We performed optic nerve decompression surgery on 17 patients with pseudotumor cerebri who, despite maximum conventional therapy, developed progressive loss of visual acuity and/or visual field. Postoperatively, visual acuity improved or stabilized in 33 of 34 eyes (97%). Visual fields improved in 20 of 21 eyes that underwent surgery. Optic nerve decompression surgery relieves local cerebrospinal fluid pressure on the optic nerve. Progressive loss of visual function associated with pseudotumor cerebri can be reversed or stabilized with optic nerve sheath decompression surgery.

Adolescent↗

PubMed1990

Age-related maculopathy. I: A review of its morphology and effects on visual function.

Age-related maculopathy (ARM) is a leading cause of permanent vision loss in elderly people. ARM therefore constitutes an important public health problem which will increase in magnitude as the number of aged people in the general population becomes greater. The consequences of this condition are exacerbated by the fact that treatment, especially of the atrophic form of the disease, is ineffective. While laser photocoagulation may be helpful in the exudative form of ARM, there is often an inexorable progression towards severe vision loss in these patients. Therefore considerable attention needs to be paid to the aetiology of ARM, the potential for its prevention or delayed onset and its recognition through functional disturbances. This is the first of three papers dealing with ARM and its effects on visual function. We review its morphology and the visual disturbances that may ensue. The second and third papers will discuss the nature and detection of the central visual field loss due to ARM.

Aging↗

PubMed1990

Visual function improvement in patients with macroprolactinomas treated with bromocriptine.

We studied eight patients who had visual field defects secondary to prolactin-secreting macroadenomas and who had improved visual function with bromocriptine treatment without surgery or radiation. We recommend bromocriptine as a primary treatment for prolactin-secreting macroadenomas. If therapy is effective, continued regular neuro-ophthalmologic, endocrine, and imaging studies are necessary, because treatment with bromocriptine must be continued indefinitely.

Adult↗