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PubMed1992

Contrast sensitivity in patients with nuclear cataracts.

Spatial contrast sensitivity and lens density were measured in 30 subjects (18 patients with pure nuclear cataracts and 12 age-matched controls). Contrast sensitivity was assessed using two techniques: a conventional monitor method in which gratings were viewed through the cataract (overall spatial contrast sensitivity) and a laser interferometer method in which gratings were formed directly on the retina (interferometric spatial contrast sensitivity), thus reducing the effect of an opaque lens on grating contrast. The degree of lens nuclear opacity was measured by assessing the density of Zeiss Scheimpflug slit-lamp video camera images. A contrast sensitivity loss was found by using both methods; this reduction reached statistical significance only when monitor stimuli were used. There was a significant correlation between lens nuclear density and sensitivity loss at spatial frequencies from 4 to 16 cycles/degree (r = .56 to .79 and P less than .05 to less than .001). A correlation coefficient of .82 (P less than .001) characterized the relationship between visual acuity (log of the minimal angle of resolution) and lens density. Nuclear lens opacity significantly affects contrast sensitivity; pure nuclear cataracts produce spatial visual losses at intermediate and high spatial frequencies.

Aged↗
PubMed2005

Impaired contrast sensitivity among leprosy patients with normal visual acuity.

Contrast sensitivity is a person's ability to identify an object from its background. Patients with normal visual acuity can have reduced contrast sensitivity and may experience trouble in identifying objects at night or moving around in dimly lit places. Contrast sensitivity has never been studied in leprosy patients having normal visual acuity. This study aimed to determine if contrast sensitivity is impaired in leprosy patients who have normal visual acuity and to identify possible associations with demographic, leprosy and ocular characteristics. A hospital based study measuring and comparing contrast sensitivity using the VCT 6500 chart in 127 consecutive leprosy patients without clinically apparent ocular complications and 123 non-leprosy controls was done. Contrast sensitivity was impaired in leprosy patients in all five spatial frequencies (1.5, 3.0, 6.0, 12 and 18 cycles/degree) investigated. Among leprosy patients, contrast sensitivity falling outside the normative range was associated with increasing age (adjusted OR 1.28, 95% CI: 1.14-1.42), being female (adjusted OR 11.05, 95% CI: 2.93-41.69) and having a grade 2 deformity (adjusted OR 6.43, 95% CI:1.68-24.61). Contrast sensitivity is impaired in leprosy patients having normal visual acuity. Elderly, deformed, female patients are particularly burdened with this vision loss.

Adolescent↗
PubMed1988

[Behavior of visual acuity, visual fields and contrast sensitivity in simulated cataract].

Visual acuity, contrast sensitivity, and visual fields were examined with and without occluders both in a group of healthy subjects and in a group of patients with field defects (mostly caused by glaucoma). The various results were compared with one another as well as with the results obtained from a group of cataract patients examined before and after surgery. The results confirm clinical experience: visual acuity enables some conclusions to be drawn on the degree and progression of opacity of a lens. The changes in contrast sensitivity and in the visual field, however, represent rather the quality of the visual degradation. Contrast sensitivity and diffuse alterations in the visual field have similar progression patterns. The alterations in contrast sensitivity are more pronounced at higher frequency levels. The contrast sensitivity test can be recommended as a simple and complementary functional test, particularly on cataract patients with severe complaints and relatively good visual acuity. The results of occlusive experiments afford some practical conclusions which enhance knowledge and differentiation of visual field changes induced by cataract and glaucoma. These conclusions can provide a basis for further and more detailed investigations.

Adult↗
PubMed2003

Distance and near contrast sensitivity function after multifocal intraocular lens implantation.

PURPOSE: To evaluate contrast sensitivity at distance and near after multifocal intraocular lens (IOL) implantation. SETTING: Ophthalmologic Institute of Alicante, University Miguel Hernández, Alicante, Spain. METHODS: Contrast sensitivity was measured with the Stereo Optical Functional Acuity Contrast Test at distance and near in 21 patients with a refractive multifocal IOL (Array SA-40N, AMO). A control group with a monofocal IOL (SI-40NB, AMO) was also studied to allow comparison of results. Contrast sensitivity was measured 1, 3, 6, 12, and 18 months after IOL implantation. RESULTS: There was a statistically significant greater reduction in contrast sensitivity at distance at all spatial frequencies in the multifocal group than in the monofocal group during the first month. At 3 months, contrast sensitivity at 12 and 18 cycles per deg remained reduced in the multifocal group; contrast sensitivity at the other frequencies did not differ from that in the monofocal group (P > 0.1). At 6, 12, and 18 months, contrast sensitivity at all spatial frequencies was not significantly different between groups (P > 0.1). There was a statistically significant greater reduction in near contrast sensitivity in the multifocal group than in the monofocal group at all spatial frequencies during the first and third month after surgery (P <.01). No statistically significant differences were found between groups after 6 months (P > 0.1). Contrast sensitivity at distance and near in the multifocal group improved over time (P <.01). CONCLUSIONS: The Array IOL provided contrast sensitivity at distance comparable to that obtained with the monofocal IOL between 3 and 6 months after implantation. Near contrast sensitivity improved over time but was always lower than at distance and in the monofocal near-corrected patients, which is acceptable to avoid near visual function degradation.

Aged↗
PubMed1998

Screening for ophthalmic disease in older subjects using visual acuity and contrast sensitivity.

OBJECTIVE: Despite early interest in contrast sensitivity as a screening test for ophthalmic disease, most published opinion suggests that there is no benefit over conventional measurement of visual acuity. Taking a primary care perspective of screening, the authors evaluated the ability to discriminate those with any diagnosed ophthalmic disease in a large sample representative of the general population. DESIGN: Retrospective analysis of a clinical, cross-sectional survey. Snellen visual acuity, contrast sensitivity (Arden plates, American Optical contrast sensitivity test), and ophthalmic diagnosis were reported previously. PARTICIPANTS: A sample of 3283 subjects, all aged at least 50 years, were selected randomly from residents of a health district in Sydney, Australia. Ophthalmologic diagnosis (ophthalmic disease presence/absence) had been confirmed for 2522 of these subjects. MAIN OUTCOME MEASURES: Signal detection techniques (the receiver-operating characteristics function [ROC], quality ROC [QROC], and weighted kappa coefficient of association [kappa(r)]) were used to evaluate test discriminability. RESULTS: Because analyses of right and left eyes were almost identical, only right eye results are presented. Advantages of kappa(r) over ROC were shown. Discrimination of those with diagnosed ophthalmic disease from those without ophthalmic disease was best with Arden plate 7 (kappa0.5 = 0.93) and was better than distance Snellen visual acuity (kappa0.5 = 0.59). Arden plate 7 (6.4 cyc/deg) correctly assigned 96% of subjects at its optimal pass-fail criterion. CONCLUSIONS: In the primary care setting, a person older than 50 years of age with reduced contrast sensitivity, as determined by Arden plate 7, requires extra care in subsequent examinations because this person is likely to have an ophthalmic disease.

Aged↗
PubMed1983

Contrast sensitivity in visually impaired children.

Spatial contrast sensitivity may decrease differently at different spatial frequencies when vision is impaired. Patients with central acidoma may have normal or decreased sensitivity at low spatial frequencies, their Snellen acuity often is lower than grating acuity estimated on the basis of contrast sensitivity values. In retinitis pigmentosa contrast sensitivity may decrease at the low spatial frequencies already in the early teens. Because the ability to discern low contrasts is important in daily living, spatial contrast sensitivity measurements should become a part of clinical evaluation of vision.

Adolescent↗
PubMed1998

Contrast sensitivity after extracapsular and intracapsular cataract extraction.

Contrast sensitivity function after cataract extraction and intraocular lens implantation has been mainly correlated to the type or the material of the intraocular lens. Our purpose was to identify other possible factors, like posterior capsule, to contrast sensitivity alterations after cataract surgery, comparing patients operated for cataract by techniques that mainly differed on the posterior capsule's integrity. The intraocular lens implanted was either a posterior or an anterior chamber one, always monofocal and made of PMMA. We measured contrast sensitivity function at four spatial frequencies in two groups of operated individuals (group A and B) and in one group of healthy control individuals. Each group consisted of 42 eyes. Group A comprised eyes with intact, clear posterior capsule and posterior chamber monofocal intraocular lens. Group B comprised eyes with ruptured or removed posterior capsule and anterior chamber monofocal intraocular lens. Control group comprised healthy control eyes. A pair matched design was used to compare contrast sensitivity values among the individuals of the three groups. No statistically significant differences in contrast sensitivity values were found when group B patients were compared to healthy controls (p >0.05). Patients of group A exhibited contrast sensitivity function impairment at intermediate and high spatial frequencies when compared to patients of group B (p <0.05) and to controls (p <0.01). It seems that intact posterior capsule provides inferior visual function, in spite of relatively good visual acuity and apparently satisfactory results.

Aged↗
PubMed1991

Isolating the effects of primary open-angle glaucoma on the contrast sensitivity function.

We evaluated spatial contrast sensitivity functions in age-matched and lens density-matched healthy eyes, eyes with primary open-angle glaucoma, and eyes with ocular hypertension. We also controlled for refraction, visual acuity, pupil size, and previous ocular history. We found an overall reduction in contrast sensitivity for the glaucomatous eyes with a significant difference at 12 cycles per degree (P less than .012). Eyes with ocular hypertension were not significantly different from normal eyes. Significant differences were noted at several spatial frequencies with less careful controls for age and lens effects. We concluded that spatial contrast sensitivity may be a useful adjunctive diagnostic test for glaucoma, but interpreting the results without other clinical data may lead to errors in diagnosis.

Aged↗
PubMed2002

[Contrast sensitivity function in myopic LASIK].

OBJECTIVE: To evaluate near contrast sensitivity function before and after myopic laser in situ keratomileusis (LASIK). METHODS: With FACT 101 test chart, static near contrast sensitivity was measured in randomly selected 47 subjects (93 eyes) before, 1 month and 6 months after LASIK. The contrast sensitivity was measured at 1.5, 3.0, 6.0, 12.0 and 18.0 cycles per degree (c/d) spatial frequency respectively and made comparison in them. RESULTS: The patients achieved the mean uncorrected visual acuity (UCVA) of 1.07 +/- 0.18 and 1.12 +/- 0.20 at postoperative 1-month and 6-months respectively. There was a general reduction in near contrast sensitivity in all spatial frequencies at postoperative 1-month when they were compared with the preoperative contrast sensitivity. The difference at 12 and 18 c/d spatial frequency was statistically significant (t test, P < 0.01). By the 6-month visit, all eyes showed a recovery of static contrast sensitivity function. The group of high myopia (preoperative > or = -6.00 D) and group with complaining of glare and halos after the surgery had a higher decrease rate of contrast sensitivity compared with that of the group preoperative < - 6.00 D and the group of patients without such complaints respectively. The differences at 6.0, 12.0 and 18.0 c/d spatial frequency at 1-month visit was statistically significant (t test, P < 0.05). CONCLUSIONS: The contrast sensitivity function test offers a more sensitive and comprehensive measure of functional vision than does standard Snellen acuity. The near contrast sensitivity in post-LASIK patients at early stage is reduced despite normal visual acuity and this can affect the quality of vision.

Adolescent↗
PubMed1995

[Visual function analysis of diabetic retinopathy using a contrast sensitivity analyser and usefulness of nicardipine hydrochloride].

Contrast sensitivity was measured in patients with mild diabetic retinopathy using a contrast sensitivity analyser on a personal computer to evaluate visual function. The effect of nicardipine hydrochloride for visual function in mild diabetic retinopathy was also evaluated. Suppression of contrast sensitivity in a comprehensive band of spatial frequency was seen in the patients with normal visual acuity. Apparent improvement of contrast sensitivity was seen in the patients after 3 months of nicardipine hydrochloride treatment. It became clear that even if patients with mild diabetic retinopathy have normal visual acuity, measurement of contrast sensitivity is very important to evaluate the visual function. We also found that nicardipine hydrochloride is effective in treating the impairment of visual function in patients with mild diabetic retinopathy.

Adult↗
PubMed2000

Age-related changes of defocus-specific contrast sensitivity in healthy subjects.

To investigate the effect of defocus on contrast sensitivity as a function of age in healthy subjects, the through focus contrast sensitivity was measured in 100 healthy subjects aged 20-69. Defocus-specific changes in contrast sensitivity reflect age-related changes in the optics of the eye. Tests were performed in cycloplegic eyes varying artificial pupil size (2, 4 and 6 mm), defocus (-1 to +2 D), and spatial frequency (1-16 cpd). Integrated contrast sensitivity was taken as a measure for the total amount of visual information transferred by the optical media. At optimal focus, integrated contrast sensitivity and log contrast sensitivity at 8 cpd showed a significant age-related decline. The log contrast sensitivity at 1 cpd appeared to be independent of age. The depth of focus for a 4-mm pupil increased significantly with age, even though contrast sensitivity at +2 D defocus decreases with age too, but not as much as the contrast sensitivity at optimal focus. Our study indicates that the effect of defocus on contrast sensitivity decreases with age; this was attributed to age-related changes in the optical media.

Adult↗
PubMed1983

Spatiotemporal contrast sensitivity and visual field locus.

Contrast sensitivity, measured as a function of retinal eccentricity for stimuli differing in temporal and spatial frequency (0.25-9 c/deg; 0-16 Hz, 0-12 degrees eccentricity), was maximum at the fovea and declined linearly with eccentricity. The slope of the decrease depended upon spatial but not temporal frequency. Contrast sensitivity for drifting gratings was approximately twice that for sinusoidal counterphase gratings at all eccentricities. For central viewing log contrast sensitivity increased with grating length. The shape of this function was systematically related to spatial frequency but independent of temporal frequency, indicating that the visual field is homogeneous in sensitivity for change in contrast over time. The implications of these findings for mechanisms of threshold vision in fovea and periphery are discussed.

Form Perception↗
PubMed1988

[Determination of contrast sensitivity].

Measurement of contrast sensitivity function (CSF) for obtaining diagnostic information on the visual system has been strongly advocated in the US literature during the last few years. The basic concepts of this type of measurement, and in particular the definition of contrast for periodic objects, are explained here. The advantages and disadvantages of different methods of measuring CSF and the correlation between CSF and visual acuity are reviewed. The article concludes with a discussion of the clinical relevance of these measurements.

Color Perception Tests↗
PubMed1985

Human contrast sensitivity: regional retinal differences.

Contrast sensitivity functions of foveal and of perifoveal upper and lower hemiretinal regions were measured in a population of twenty subjects. Foveal stimuli yielded consistently higher contrast sensitivities as well as a shift of the maximal sensitivity towards higher spatial frequencies as compared to perifoveal stimuli. The upper hemiretinal area was more sensitive at all spatial frequencies tested than the corresponding lower hemiretinal area. The statistical comparisons were highly significant, indicating not only regional retinal differences in visual acuity as reflected by the different contrast threshold levels at the highest spatial frequency, but also global differences between the upper and lower hemiretina systems not restricted to certain spatial frequency channels.

Adult↗
PubMed1986

Contrast sensitivity in amblyopia. I. Changes during CAM treatment.

Contrast sensitivity of 29 children (mean age 8 years) was measured at the beginning, at the end, and during the follow-up of CAM treatment. The deficiency in contrast sensitivity of amblyopic eyes was most notable at high spatial frequencies, but in some cases it also occurred at intermediate and low spatial frequencies. Individually no distinct association was noticed between various CSF-types and different groups of amblyopia, but on average in anisometropia the deficiency at low spatial frequencies was more pronounced than in purely strabismic cases. During treatment contrast sensitivity improved significantly, most notable at high frequencies. Correlation between visual acuity and contrast sensitivity was poor. During follow-up visual acuity deteriorated in most cases, but contrast sensitivity remained on the level where it was at the end of the treatment. Our modification of measuring contrast sensitivity was tested in two samples of normal subjects. Between 1-11 c/deg contrast sensitivity was statistically significantly better in the adults (n = 25) than in the children (n = 20).

Adolescent↗
PubMed1982

Temporal contrast sensitivity in amblyopia.

Temporal contrast sensitivity functions were determined for the normal (20/20) and amblyopic eyes of five strabismic and/or anisometropic amblyopes and for both eyes of two nonamblyopes. In deep amblyopia (20/100+), contrast sensitivity was reduced at all temporal frequencies in the amblyopic eye, whereas no deficit was observed for subjects whose acuity was 20/40 or better. This result indicates that reduced temporal sensitivity is a significant component of strabismic and anisometropic amblyopia.

Adult↗
PubMed1986

Alterations of visual contrast sensitivity in Parkinson's disease.

Contrast sensitivity functions were determined in a population of 18 patients suffering from Parkinson's disease, and compared with the data obtained in an age-matched group of healthy controls. The controls were more sensitive at all spatial frequencies tested than the patients. The statistical comparisons were highly significant, indicating general differences between the PD patients and the controls not related to individual spatial frequency channels. When comparing the sensitivity loss between low and high spatial frequencies no significant differences were found suggesting that the decrease in contrast sensitivity is a global effect. We controlled for effects of age and cerebral atrophy, and our findings cannot be accounted for by these factors. In addition, the amount of contrast sensitivity loss was not correlated with the severity of the disease. These global functional alterations appear to be related to the reduction of dopamine at various sites of the visual system.

Adult↗
PubMed1991

The importance of measuring binocular contrast sensitivity in unilateral cataract.

Monocular and binocular contrast sensitivities were measured in patients with uniocular cataract. The cataractous eye showed a greater monocular loss at higher spatial frequencies compared to lower spatial frequencies. Binocular contrast sensitivity depended on the contrast sensitivity differences between the two eyes. At low spatial frequencies, where the monocular sensitivity difference was minimal, binocular summation was obtained. As the sensitivity difference increased at higher spatial frequencies, the binocular contrast sensitivity decreased steadily until it reached a level below the sensitivity of the cataractous eye, demonstrating binocular inhibition. The clinical implications of binocular inhibition obtained with uniocular cataract are discussed.

Aged↗