Contrast Sensitivity Testing Research Articles

Improvement of positive dysphotopsia with multifocal intraocular lenses by hormone replacement therapy

Introduction: The case of a patient with positive dysphotopsia (PD) affected by hormone replacement therapy (HRT) after multifocal intraocular lens (IOL) insertion is reported. Patient and Clinical Findings: A 66-year-old woman underwent bilateral cataract surgery and multifocal IOL implantation. Postoperatively, the uncorrected distance and near visual acuity improved bilaterally. The patient experienced mild PD symptoms in the left eye. She had been using an estradiol patch for menopausal disorders. 6 months postoperatively, the use of an estradiol patch was discontinued because of dermatitis and she noticed a marked worsening of her PD. Diagnosis, Intervention, and Outcomes: With the patient's cooperation, full-field electroretinography (ERG) and contrast sensitivity tests were performed before and after estradiol discontinuation. After the discontinuation, the amplitude of both rod and cone ERGs decreased, contrast sensitivity decreased, and PD deteriorated. There were no changes in anterior-segment condition and retinal shape. Conclusions: PD symptoms worsened after the discontinuation of estrogen hormone therapy. ERG amplitude and contrast sensitivity decreased when HRT was discontinued, suggesting that retinal function in the presence of estrogen receptors may be related to the development of PD.

Can children measure their own vision? A comparison of three new contrast sensitivity tests.

To investigate the feasibility of children measuring their own contrast sensitivity using a range of tablet- and paper-based tests. Forty children aged 5-15 years with amblyopia (N = 10), bilateral vision impairment (N = 10) or good vision (N = 20) measured their own vision on a screen-based optotype test (Manifold), a gamified vision test (PopCSF) and a paper-based test (Spotchecks) in a laboratory with minimal supervision. Completion rate, test-retest repeatability, test duration and participants' preferences were recorded for each test. Most participants (36/40) were able to perform all three tests. All tests were correlated with clinically measured visual acuity and contrast sensitivity (p < 0.001). The 95% coefficient of repeatability was 0.30 dB for Manifold, 0.29 dB for PopCSF and 0.13 dB for Spotchecks. All tests differentiated between children with reduced contrast sensitivity and control participants. PopCSF and Spotchecks were also able to differentiate between children with amblyopia and those with good vision. Median test time was 152, 130 and 202 s for Manifold, PopCSF and Spotchecks, respectively. Twenty-two participants preferred the PopCSF test, 10 preferred Spotchecks and 6 preferred Manifold. Thirty-nine out of the 40 children (98%) said they would measure their own vision at home using at least one of these tests every month. Children and young people can test their own contrast sensitivity with repeatable results. Of these three tests, the most repeatable was Spotchecks, the quickest was PopCSF and participants' favourite was PopCSF. Nearly all of the participants said they would be willing to use at least one of the three tests at home.

Monocular and Binocular Visual Function Assessments and Activities of Daily Living Performance in Age-Related Macular Degeneration

To evaluate the relationship between specific monocular and binocular visual function (VF) assessments with binocularly performed activities of daily living task tests (ADLTTs) in patients with age-related macular degeneration (AMD) and healthy controls. Prospective case-control cohort study. Thirty-six AMD patients and 36 controls. Visual field assessments included monocular and binocular best-corrected visual acuity (BCVA), contrast sensitivity (CS), and monocular microperimetry testing for mean macula sensitivity, mean retina sensitivity (MRS), fixation area, and fixation distance from fovea (FDF). Age-related macular degeneration lesion area and sensitivity were measured on OCT and microperimetry, respectively. Participants performed 4 validated ADLTTs with binocular BCVA: (1) reading; (2) item-search; (3) money-counting; and (4) multi-step drink-making tasks. Spearman correlations and multivariate regression analysis, adjusted for age, sex, and potential correlation between the 2 eyes, were used to assess the relationship between monocular and binocular VF assessments, and ADLTT performance in both groups. Age-related macular degeneration patients had poorer VF (BCVA, CS, mean macula sensitivity, and MRS) compared with healthy controls. Monocular BCVA in both better- and worse-vision eyes was moderately correlated with the binocular reading speed and money-counting tasks in participants with AMD. In AMD, monocular worse eye CS, MRS, AMD lesion area on OCT, and lesion sensitivity on microperimetry showed moderate correlations to various ADLTTs, such as reading, money-counting, and drink-making. Similar findings were found in our AMD cohort on multivariate regression analysis. Fewer significant correlations were observed for the better-vision eye, whereas no correlations were observed for healthy controls between VF parameters and ADLTTs. In contrast, significant associations were observed between binocular BCVA and CS with binocular ADLTTs (reading and item-search tasks) but not in AMD patients. Although monocular BCVA remains the most common measure of VF, CS and microperimetry testing also show significant correlations with ADLTTs performance in AMD patients, and should be considered as complimentary VF-outcome measures in both clinical and research settings. Unlike healthy subjects, AMD patients do not rely on binocular VF for ADLTT function, with the worse-vision eye impacting binocular ADLTT function more than the better-vision eye. Therefore, the worse-vision eye should not be neglected during the management of AMD. Proprietary or commercial disclosure may be found after the references.

Assessment of Visual Habituation Measured With the Halo & Glare Simulator and Its Impact on Patient Satisfaction Following Quadrifocal IOL Implantation.

To evaluate the levels of habituation and its influence on outcome satisfaction in patients who underwent bilateral multifocal intraocular lens (IOL) implantation. A total of 24 patients underwent bilateral multifocal IOL implantation surgery with the AcrySof IQ PanOptix trifocal diffractive IOL (Alcon Laboratories, Inc) following cataract extraction or for refractive purposes. Data were collected 3 and 6 months after surgery, which included subjective refraction, corrected and uncorrected visual acuity (distance, intermediate, near), a contrast sensitivity test, simulation with the Halo & Glare Simulator (Carl Zeiss Meditec AG), two visual quality surveys, and a slit-lamp examination by an ophthalmologist. All patients were spectacle independent for distance vision and 92% (n = 22) needed no visual aid for near vision. Minor visual acuity improvement was detected between both examinations at monocular uncorrected distance visual acuity (P = .025). Improvements of presence, size, and intensity of visual disturbances were not statistically significant, but overall patient satisfaction (P = .009) and Weber-Contrast sensitivity under mesopic conditions (P = .029) increased significantly. Diffractive multifocal IOLs are a stable treatment for presbyopia and/or cataract with a high spectacle independence rate. Visual disturbances caused by their optics do not decrease significantly between 3 and 6 months after surgery. Habituation and neuroadaptation play a significant role in patient satisfaction and contrast sensitivity during and possibly beyond that period. [J Refract Surg. 2023;39(8):510-517.].

Characterization of vision in pediatric retinoblastoma survivors beyond visual acuity

Retinoblastoma (RB) and its associated treatments can significantly impact visual acuity. However, little is known regarding other measures of vision, such as contrast sensitivity or saccades. The aim of this study was to describe contrast sensitivity and saccades in children treated for retinoblastoma. This cross-sectional study included children aged 5-17 years who had completed treatment for RB. Visual acuity, saccades via fixation analysis, and contrast sensitivity by Cardiff contrast sensitivity were assessed, and multivariable linear regression was performed. Eleven children were enrolled (mean age, 10.7 ± 3.9 years). Treatment included enucleation (8 children [73%]) and chemotherapy (10 [91%]). Of the 11, one participant was unable to complete testing of saccades, and another was unable to complete contrast sensitivity testing. Decreased saccade parameters (velocity, latency, or accuracy) and impaired contrast sensitivity were observed in all 10 participants who underwent visual testing. Multivariable analysis revealed that worse logMAR visual acuity (B, -4.54 [-6.8, -2.2]; P = 0.004) and bilateral disease (B, -3.9 [-6.4, -1.4]; P = 0.009) were associated with worse contrast sensitivity. Germline disease was associated with decreased vertical saccade accuracy (P = 0.02). Decreased contrast sensitivity and impaired saccades were universally observed in this cohort of RB survivors. Comprehensive visual evaluation should be considered for all RB survivors to provide optimal rehabilitative services for these patients.

Comparison of current paediatric contrast sensitivity assessments using simulated reduced contrast thresholds

ABSTRACT Purpose There are limited tests of contrast sensitivity (CS) for use in children. The Hiding Heidi (HH) is suitable for all cognitive abilities, but has a ceiling effect. The Double Happy (DH) test has comparable thresholds to the Pelli Robson (PR), however the ability to detect changes in contrast has not been established. This study aims to compare contrast thresholds and agreement between HH and the DH, comparing to the PR chart in normal conditions and under reduced visual and lighting conditions. Methods Tests were repeated under different conditions to reduce the contrast. Room illumination was 20,900{plus minus}2% lux in bright conditions and 2,000{plus minus}2% lux in dim conditions, both conditions were repeated with the addition of simulation spectacles to reduce the clarity of vision. Participants’ CS was measured uniocularly using the PR, HH and DH tests. Results 50 participants, age 18–62 years (mean{plus minus}standard deviation: 24.5{plus minus}7.98), were assessed. On HH 94% (n = 47) reached the maximum score, with the DH it was 18% (n = 9). The difference in reduction between conditions was smaller with HH in comparison to PR and DH, but significantly different from baseline conditions. Under dim conditions the reduction in PR and DH was −0.21 logCS units, but only −0.04 logCS for HH. Conclusion The DH test has better agreement with PR than HH and is better at detecting CS changes, highlighting the advantages of use in clinical practice.

RECURRENT FLOATERS AFTER LIMITED VITRECTOMY FOR VISION DEGRADING MYODESOPSIA.

Limited vitrectomy improves vision degrading myodesopsia, but the incidence of recurrent floaters postoperatively is not known. We studied patients with recurrent central floaters using ultrasonography and contrast sensitivity (CS) testing to characterize this subgroup and identify the clinical profile of patients at risk of recurrent floaters. A total of 286 eyes (203 patients, 60.6 ± 12.9 years) undergoing limited vitrectomy for vision degrading myodesopsia were studied retrospectively. Sutureless 25G vitrectomy was performed without intentional surgical posterior vitreous detachment (PVD) induction. CS (Freiburg Acuity Contrast test: Weber index, %W) and vitreous echodensity (quantitative ultrasonography) were assessed prospectively. No eyes (0/179) with preoperative PVD experienced new floaters. Recurrent central floaters occurred in 14/99 eyes (14.1%) without complete preoperative PVD (mean follow-up = 39 months vs. 31 months in 85 eyes without recurrent floaters). Ultrasonography identified new-onset PVD in all 14 (100%) recurrent cases. Young (younger than 52 years; 71.4%), myopic (≥-3D; 85.7%), phakic (100%) men (92.9%) predominated. Reoperation was elected by 11 patients, who had partial PVD preoperatively in 5/11 (45.5%). At study entry, CS was degraded (3.55 ± 1.79 %W) but improved postoperatively by 45.6% (1.93 ± 0.86 %W, P = 0.033), while vitreous echodensity reduced by 86.6% ( P = 0.016). New-onset PVD postoperatively degraded CS anew, by 49.4% (3.28 ± 0.96 %W; P = 0.009) in patients electing reoperation. Repeat vitrectomy normalized CS to 2.00 ± 0.74%W ( P = 0.018). Recurrent floaters after limited vitrectomy for vision degrading myodesopsia are caused by new-onset PVD, with younger age, male sex, myopia, and phakic status as risk factors. Inducing surgical PVD at the primary operation should be considered in these select patients to mitigate recurrent floaters.

Cone-isolation contrast sensitivity – do pupil and stimulus sizes matter?

ABSTRACT Clinical relevance Computer-based colour perception tests permit clinical assessment of cone-specific pathways, proving valuable for both identifying type and severity of hereditary colour vision deficiency and enhanced detection and monitoring of acquired colour deficiency from disease. Understanding the parameters that affect computer-based colour perception tests may enhance their veracity and clinical utility. Background Testing contrast sensitivity separately for the three cone systems enables a quantification of colour perception that can be clinically useful. This study evaluated the effects of pupil diameter and stimulus size on cone contrast sensitivity (CCS) assessed with the ColorDx (Konan Medical, Incorporated). Methods Forty subjects, aged 21–31 years, who met the inclusion criteria participated. The tested eye was randomised. Two Landolt C sizes (2.68 degrees, 6/194, “small”; 8.58 degrees, 6/619, “large”) were used, with one size and three chromaticities presented per block of trials. Stimulus presentation used the adaptive screening mode, sequentially determining contrast sensitivity for long-, medium-, and short-wavelength stimuli. Subjects were tested with their natural pupil size (range 4–5 mm diameter), then while viewing through a 2.5-mm artificial pupil. Parametric statistical tests were used for comparisons of performance across pupil size and stimulus size. Results Two-way within-subjects ANOVA indicates no interaction between pupil size and stimulus size for any of the three stimulus chromaticities. The main effect of stimulus size was significant for M-cone (F = 6.506, 2-tailed P = .015) and S-cone (F = 67.728, 2-tailed P < .001) stimuli. The main effect of pupil size was significant for all three stimulus chromaticities (L-cone: F = 227.161, M-cone: F = 249.979, S-cone: F = 89.371, 2-tailed P < .001 for all). Conclusion Although CCS was reduced for all three chromaticities and both stimulus sizes with lower retinal illuminance, only S-wavelength cone contrast sensitivity was significantly different for the small versus large stimuli under the 2.5-mm pupil condition in this cohort. Whether CCS in older patients with naturally small pupils changes with an enlarged stimulus or dilated pupils remains to be explored.

Blue-light stimulation of the blind-spot constricts the pupil and enhances contrast sensitivity.

Short- and long-wavelength light can alter pupillary responses differently, allowing inferences to be made about the contribution of different photoreceptors on pupillary constriction. In addition to classical retinal photoreceptors, the pupillary light response is formed by the activity of melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGC). It has been shown in rodents that melanopsin is expressed in the axons of ipRGCs that bundle at the optic nerve head, which forms the perceptual blind-spot. Hence, the first aim of this study was to investigate if blind-spot stimulation induces a pupillary response. The second aim was to investigate the effect of blind-spot stimulation by using the contrast sensitivity tests. Fifteen individuals participated in the pupil response experiment and thirty-two individuals in the contrast sensitivity experiment. The pupillary change was quantified using the post-illumination pupil response (PIPR) amplitudes after blue-light (experimental condition) and red-light (control condition) pulses in the time window between 2 s and 6 s post-illumination. The contrast sensitivity was assessed using two different tests: the Freiburg Visual Acuity Test and Contrast Test and the Tuebingen Contrast Sensitivity Test, respectively. Contrast sensitivity was measured before and 20 minutes after binocular blue-light stimulation of the blind-spot at spatial frequencies higher than or equal to 3 cycles per degree (cpd) and at spatial frequencies lower than 3 cpd (control condition). Blue-light blind-spot stimulation induced a significantly larger PIPR compared to red-light, confirming a melanopsin-mediated pupil-response in the blind-spot. Furthermore, contrast sensitivity was increased after blind-spot stimulation, confirmed by both contrast sensitivity tests. Only spatial frequencies of at least 3 cpd were enhanced. This study demonstrates that stimulating the blind-spot with blue-light constricts the pupil and increases the contrast sensitivity at higher spatial frequencies.

Vision screening and vocational aptitude: A factor analysis approach.

For a good vision screening battery to quickly and accurately reflect the status of the human visual system it should be relevant, reliable, and streamlined. Because the early visual system has limited functional architecture, many simple measurements of the visual system may in fact be measuring the shared computations and parallel processes of other visual functions, making much of the measurement process redundant. This can make a screening battery repetitious and therefore inefficient. The purpose of this research is to investigate these redundancies in a large occupational screening dataset using factor analysis. 192 subjects participated in the Operational Based Vision Assessment (OBVA) Laboratory Automated Vision Testing (AVT) procedure. The AVT includes digital tests for visual acuity, luminance and cone contrast sensitivity, motion coherence, stereopsis, and binocular motor function. Psychometric thresholds and fusional ranges were collected from each subject and a factor analysis was utilized to investigate independent latent variables in the dataset. A promax rotation revealed 5 factors that explained 74% of the total variance: (1) medium and high spatial frequency vision, (2) stereoacuity and horizontal fusional range, (3) cone contrast sensitivity, (4) motion perception, and (5) low spatial frequency vision. Practically, these results suggest that the screening battery can be reduced to 5 independent measurements that capture much of the variance in the dataset. Furthermore, the factors predicted operational and vocational aptitude better than any single variable. More interestingly, these relationships also reiterate known computational processes within the human visual system, such as the parallel processing of low and high spatial frequency content.

The spatial contrast sensitivity function and its neurophysiological bases

Contrast processing is a fundamental function of the visual system, and contrast sensitivity as a function of spatial frequency (CSF) provides critical information about the integrity of the system. Here, we used a novel iPad-based instrument to collect CSFs and fitted the data with a difference of Gaussians model to investigate the neurophysiological bases of the spatial CSF. The reliability of repeat testing within and across sessions was evaluated in a sample of 22 adults for five spatial frequencies (0.41–13 cycles/degree) and two temporal durations (33 and 500 ms). Results demonstrate that the shape of the CSF, lowpass versus bandpass, depends on the temporal stimulus condition. Comparisons with previous psychophysical studies and with single-cell data from macaques and humans indicate that the major portion of the CSF, spatial frequencies >1.5 cycles/degree regardless of temporal condition, is determined by a ‘sustained’ mechanism (presumably parvocellular input to primary visual cortex [V1]). Contrast sensitivity to the lowest spatial frequency tested appears to be generated by a ‘transient’ mechanism (presumably magnocellular input to V1). The model fits support the hypothesis that the high spatial frequency limb of the CSF reflects the receptive field profile of the center mechanism of the smallest cells in the parvocellular pathway. These findings enhance the value of contrast sensitivity testing in general and increase the accessibility of this technique for use by clinicians through implementation on a commercially-available device.

Functional visual tests to evaluate the effect of small astigmatism correction with toric contact lenses.

The prescription of daily contact lenses does not often include a full astigmatic correction. We question here whether this full astigmatic correction (for low to moderate astigmatism) provides a substantial improvement in the overall visual performance compared to a more conservative approach based only on the prescription of spherical contact lenses. The visual performance of 56 contact lens neophytes divided in two contact lens fitting groups (toric versus spherical lens fit) was assessed using standard visual acuity and contrast sensitivity tests. A new set of functional tests simulating everyday tasks was also used. Results showed that subjects with toric lenses had significantly better visual acuity and contrast sensitivity than those with spherical lenses. Functional tests did not render significant differences between groups, which was explained by several factors like i) the visual demand of the functional tests, ii) the dynamic blur due to misalignments and iii) small misfits between the available and measured axis of the astigmatic contact lens.

The short-term influences of paediatric smartphone use on the eye

The aim of this study is to comprehensively evaluate the effect of smartphone use on the eye. Twenty-two children, aged 8-16 years, participated in this study. A self-administered questionnaire about smartphone usage time, outdoor activities, and sleep time to obtain dry eye was applied to the child and parents. An ocular surface disease index (OSDI), tear break-up time (TBUT), blink time, autorefractometer, optical biometry, accommodation, contrast sensitivity, and optical coherence tomography tests were applied before a 5-min video watching, and during the video session we counted the complete -incomplete blinks. After video watching, we did the tests. After the tests, we again applied a 5-min video watching and after the video we tested all the parameters again, and finally, following a 5-min resting period, we tested the parameters again. We found no difference between the groups in terms of OSDI scores. Children with punctate epithelial erosions and time spent on the phone have a statistical relation. TBUT also differs statistically before and after test periods ( p = .014), since complete blinks did not differ but incomplete blinks differed before and after video watching. The nearpoint of convergence also differs after video watching ( p = .008) and anterior chamber depth (ACD) decreases even after the short-time video watching period. On the contrary, we did not find any effect of short-time smartphone watching on auto-keratometer values and retinal-choroidal thickness. This is the first comprehensive study on the short-term effects of smartphone on the paediatric age group. Even 10 min of smartphone can have an effect on TBUT, incomplete blinks, nearpoint of convergence break-recovery, and ACD. During this coronavirus disease 2019 pandemic, we must be mindful of the time our children spend on the phone and keep in mind that even 10 min can have ocular effects.

Assessment of amblyopic children undergoing occlusion therapy by pattern visual evoked potentials and contrast sensitivity tests.

Background: Amblyopia is a case where one or less commonly, both eyes have impaired visual performance, even with the best optical correction and no visible disease of the visual system. Objectives: To assess contrast sensitivity tests (CST) and pattern visual evoked potentials (PVEP) results in amblyopic children who have already started occlusion therapy for durations ranging from 6 to 12 months. Methods: This cross-sectional study was conducted on 200 eyes of 50 patients with monocular amblyopia and 50 age and sex matched controls. Both patients and controls underwent ophthalmological assessment, PVEP, and CST. Results: There was no statistically significant difference in the results of P100 latencies of qualitative PVEP in amblyopic eyes compared to non-amblyopic eyes and control eyes, while the qualitative CST showed a highly statistically significant difference, being affected in 98% of amblyopic eyes compared to unaffected eyes (4%) and control eyes (4%). The maximum contrast level and minimal contrast level of quantitative CST were significantly lower in amblyopic eyes compared to non-amblyopic and control eyes. The cutoff value of maximal contrast level at mean frequencies of 2.5 ± 0.9 Hz, and a range of (1.1-4.1) for amblyopic eyes is ≤21 dB, while the cutoff value of minimal contrast level at mean frequencies of 13.4 ± 2.6 Hz, and a range of (6.7-18) for amblyopic eyes is ≤12 dB. Conclusion: Detection of amblyopia by CST is a noninvasive and easy procedure, which represents a promising tool to support the diagnosis of amblyopia.

Clinical outcomes of bilateral implantation of new generation monofocal IOL enhanced for intermediate distance and conventional monofocal IOL in a Korean population

BackgroundTo compare the clinical outcomes of bilateral implantation of enhanced intermediate function intraocular lenses (IOLs) and standard monofocal IOLs.MethodsIn this prospective, randomized, comparative controlled study, we compared the visual outcomes of patients who underwent bilateral cataract surgery at the Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, with either enhanced monofocal IOLs (Tecnis Eyhance, ICB00, Johnson and Johnson Vision Care, Inc) (Group 1) or standard monofocal IOLs (Tecnis, ZCB00, Johnson and Johnson Vision Care, Inc) (Group 2). The assessment included monocular and binocular uncorrected distance visual acuity (UDVA), uncorrected intermediate (UIVA at 60 cm) and near (UNVA at 40 cm) visual acuity, uncorrected defocus curves, contrast sensitivity testing (CST), and reading speed test using Quality of vision was evaluated using the Visual Function Questionnaire (VFQ-25).ResultsAt 3-months postoperatively, monocular and binocular outcomes of UIVA and UNVA were statistically significantly better in Group 1 (P < 0.05). The binocular uncorrected defocus curve of Group 1 showed statistically significantly better outcomes at vergence ranges of -1.5 to -4.0 D (P < 0.05). Significantly higher reading speed test was also observed in Group 1 in all ranges tested (1.0 to 0.1 LogMAR) (P < 0.05). There were no statistically significant differences in CST between groups.ConclusionsBilateral implantation of enhanced monofocal IOLs provided better vision at intermediate and near distances compared to standard monofocal IOLs, while maintaining good distance vision and contrast sensitivity.

Association Between Contrast Sensitivity and Central Subfield Thickness in Center-Involving Diabetic Macular Edema.

Purpose: To evaluate the association between contrast sensitivity (CS) and central subfield thickness (CST) in diabetic macular edema (DME). Methods: This prospectively recruited, cross-sectional study included eyes with DME evaluated from November 2018 to March 2021. CST was measured using spectral-domain optical coherence tomography on the same day as CS testing. Only eyes with center-involving DME (CST >305 µm for women; >320 µm for men) were included. CS was evaluated using the quantitative CS function (qCSF) test. Outcomes included visual acuity (VA) and the following qCSF metrics: area under the log CS function, contrast acuity (CA), and CS thresholds at 1 to 18 cycles per degree (cpd). Pearson correlation and mixed-effects regression analyses were performed. Results: The cohort included 52 eyes of 43 patients. Pearson correlation analysis showed a stronger association between CST and CS thresholds at 6 cpd (r = -0.422, P = 0.002) than CST and VA (r = 0.293, P = 0.035). Mixed-effects univariate and multivariate regression analyses showed significant associations between CST and CA (β = -0.001, P = .030), CS at 6 cpd (β = -0.002, P = .008), and CS at 12 cpd (β = -0.001, P = .049) but no significant associations between CST and VA. Among the visual function metrics, the effect size of CST was largest on CS at 6 cpd (βStandardized = -0.37, P = .008). Conclusions: In patients with DME, CS may be more strongly associated with CST than VA. Including CS as an adjunct visual function outcome measure in eyes with DME may prove clinically valuable.

Comparision of the Contrast Sensitivity Test with Different Modes of Refractive Correction in Myopes with Low Astigmatism

Comparision of the Contrast Sensitivity Test with Different Modes of Refractive Correction in Myopes with Low Astigmatism

Display Characterization for Contrast Sensitivity Testing

Contrast sensitivity measurements using a computer display have been reported to lack accuracy when displaying small contrasts. This report investigates if the characterization/calibration of display luminance may contribute substantively to these kinds of described inaccuracies. This study aimed to investigate what errors in contrast sensitivity may result from characterizing a display by fitting a gamma curve through physical or psychophysical luminance measurement data. The luminance functions of four different in-plane switching liquid crystal displays (IPS LCDs) have been measured for all 256 gray levels (the actual luminance function). This has been compared with a gamma-fitted luminance curve (the gamma luminance function). Calculated are the errors in displayed contrast that may arise when assuming the gamma luminance function instead of the actual luminance function. The amount of error differs considerably between the displays. In general, for large contrasts (Michelson log CS <1.2), the error is acceptable (<<0.15 log unit). However, for smaller contrasts (Michelson log CS >1.5), the error may become unacceptably high (>0.15 log unit). To improve the accuracy of testing contrast sensitivity with an LCD, it is necessary to fully characterize the display, measuring the luminance of each gray level instead of fitting a smooth gamma function through limited luminance data.

Remote Contrast Sensitivity Testing Seems to Correlate With the Degree of Glaucomatous Macular Damage.

Remote contrast sensitivity (CS) testing through a free downloadable home test correlates with glaucomatous macular damage measured by 10-2 visual field (VF) testing. To assess the feasibility and validity of home CS monitoring as a measure of glaucomatous damage using a free downloadable smartphone application. Twenty-six participants were asked to remotely use the Berkeley Contrast Squares (BCS) application, a free downloadable tool that records the user's CS for varying degrees of visual acuity. An instructional video detailing how to download and use the application was sent to the participants. Subjects were asked to send logarithmic CS results with a minimum 8-week test-retest window, and test-retest reliability was measured. Results were validated against office-based CS testing that was collected within the previous 6 months. Validity analysis was also carried out to determine whether CS as measured by BCS is a good predictor of 10-2 and 24-2 VF mean deviation (MD). There was a high BCS test-retest reliability with an intraclass correlation coefficient score of 0.91 and a significant correlation between repeat test results and baseline test scores (Pearson, 0.86, P < 0.0001). There was significant agreement between unilateral CS scores as measured by BCS and office-based CS testing ( b = 0.94, P < 0.0001, 95% CI: 0.61 to 1.27). Unilateral CS as measured by BCS was significantly associated with 10-2 VF MD ( r2 = 0.27, P = 0.006, 95% CI: 3.7 to 20.6), but not with 24-2 VF MD ( P = 0.151). This study suggests that a free, rapid home CS test correlates with glaucomatous macular damage as measured by 10-2 VF.

A study on disability glare vision in young adult subjects

The full assessment of the visual system must include the evaluation of the optical quality of the eye and neural visual functions. The objective evaluation of the retinal image quality is often carried out by computing the point spread function (PSF) of the eye. The central part of the PSF is associated with optical aberrations and the peripheral areas with scattering contributions. In that sense, visual acuity and contrast sensitivity function tests can be considered the perceptual neural response to those contributions characterizing the eye’s PSF. However, in natural viewing conditions, visual acuity tests may provide good vision while contrast sensitivity tests can reveal visual impairment in glare vision conditions, such as exposure to bright light sources or night driving conditions. Here we present an optical instrument for the study of disability glare vision under extended Maxwellian illumination to assess the contrast sensitivity function under glare conditions. The limit of the Total Disability Glare threshold, tolerance, and glare adaptation will be investigated as a function of the angular size of the glare source (GA) and the contrast sensitivity function in young adult subjects.