Pelli-Robson Contrast Sensitivity Research Articles

Psychometric Properties of the Vietnamese Catquest-9 Short Form Questionnaire.

The Catquest-9 Short Form (SF) has good psychometric properties but was not available in Vietnamese. This study provides the Vietnamese Catquest-9SF and evidence supporting for its use in hospital settings along with clinical assessment to evaluate visual function. The purpose of this study was to evaluate the psychometric properties of the Vietnamese Catquest-9SF. Literate patients with unilateral/bilateral cataract, without severe systemic and ocular comorbidities, aged 50+ years, and scheduled for first-eye surgery were screened and recruited at the University of Medicine and Pharmacy at Ho Chi Minh City and Trung Vuong Hospital. Age, sex, and education were self-reported. The Catquest-9SF and the 25-item National Eye Institute Visual Function Questionnaire were used to assess vision-related quality of life (VRQOL). Best-corrected unilateral and bilateral log of the minimum angle of resolution (logMAR) visual acuity was measured, as was best-corrected Pelli-Robson contrast sensitivity. Rasch analysis was performed on the Vietnamese version of the Catquest-9SF. Criterion validity and convergent validity were also evaluated. Andrich thresholds and response categories on each Catquest-9SF item were ordered, indicating that patients were able to discriminate VRQOL levels. Person separation index and reliability were 2.51 and 0.86, respectively, indicating that the Catquest-9SF was able to distinguish between patients with low- and high-vision difficulties. The tool was unidimensional, with all items fitting well within the construct. There was no evidence of differential item functioning by sex, age group, or cataract status. The tool also showed criterion validity, correlating significantly with visual acuity in the better eye (r = -0.46), the worse eye (r = -0.39), and both eyes (r = -0.44), and with contrast sensitivity for the better eye (r = 0.41), the worse eye (r = 0.32), and both eyes (r = 0.39). A strong correlation between the Catquest-9SF and the 25-item National Eye Institute Visual Function Questionnaire (r = 0.87) indicated convergent validity. The Vietnamese Catquest-9SF is valid and psychometrically robust for assessing VRQOL among cataract patients.

Prospective study to evaluate the effectivity and acceptance of optical low vision AIDS

Prospective study to evaluate the effectivity and acceptance of optical low vision AIDS - IJCEO- Print ISSN No: - 2395-1443 Online ISSN No:- 2395-1451 Article DOI No:- 10.18231/j.ijceo.2019.102, Indian Journal of Clinical and Experimental Ophthalmology-Indian J Clin Exp Ophthalmol

Development and Validation of a Smartphone-based Contrast Sensitivity Test.

PurposeContrast sensitivity (CS) testing is an important measure of visual function reflecting variations in everyday visual experience in different conditions and helps to identify more subtle vision loss. However, it is only infrequently used. To make this more accessible, we have developed and validated a smartphone-based CS test.MethodsA new tumbling-E smartphone-based CS test was developed, Peek Contrast Sensitivity (PeekCS). This was field tested and refined through several iterations. Reference standard was a tumbling-E Pelli-Robson CS test (PRCS). The validation study was conducted in community clinics in Ethiopia. Test-retest variability was measured for both PRCS and PeekCS. PRCS and PeekCS were then compared. Correlation coefficients and 95% confidence intervals (CIs) were calculated; 95% limits of agreement were calculated and displayed on Bland-Altman plots.ResultsPeekCS showed strong repeatability (correlation coefficient: 0.93; 95% CI: 0.91–0.95), which was comparable with PRCS (correlation coefficient: 0.96; 95% CI: 0.95–0.97). The 95% limit of agreement for test-retest variability of PRCS and PeekCS were −0.20 to 0.21 and −0.31 to 0.29, respectively. PRCS and PeekCS were highly correlated: 0.94 (95% CI: 0.93–0.95); 95% limits of agreement −0.27 to 0.29; and mean difference 0.010 (95% CI: −0.001 to 0.022). PeekCS had a faster testing time (44.6 seconds) than PRCS (48.6 seconds): mean difference −3.98 (95% CI: −5.38 to −2.58); P < 0.001.ConclusionsThe smartphone-based PeekCS is a repeatable and rapid test, providing results that are highly comparable with the commonly used PRCS test.Translational RelevancePeekCS provides an accessible and easy to perform alternative for CS testing, particularly in the community setting.

'You've got dry macular degeneration, end of story': a qualitative study into the experience of living with non-neovascular age-related macular degeneration.

To investigate the impact of non-neovascular (dry) age-related macular degeneration (AMD) on the person with respect to diagnosis, vision loss and coping strategies. Volunteers with dry AMD with a range of disease severity were given an eye examination and asked to describe aspects of their experience with dry AMD in a semi-structured interview. Interviews were audio-recorded, transcribed, and subjected to Framework analysis. Overarching themes were pre-defined, whilst subthemes were derived from the data. Twenty-seven participants (81% female), with early (n = 3), intermediate (n = 16) and advanced dry AMD (GA; n = 8) were interviewed. Median (interquartile range) age (years), logMAR binocular visual acuity and Pelli-Robson contrast sensitivity were 76 (71, 80), 0.2 (0.18, 0.40) and 1.65 (1.35, 1.93), respectively. Overarching themes (and subthemes) were: diagnosis (relationship with healthcare professional, psychological impact of diagnosis, and knowledge of AMD, both pre- and post-diagnosis), impact of visual loss (functional and psychological) and coping strategies (help from others and personal strategies). Many participants reported feelings of distress at the time of diagnosis and, particularly noteworthy, several reported a constant fear of their condition worsening. Dry AMD, for which there is currently no treatment, can have a significant impact on individuals, even in its early stages, before significant functional vision loss is manifest, as well as in its intermediate and advanced stages. Results from this study offer important insight into the experience of living with dry AMD not previously explored. Moreover, the results have the potential to serve as an educational resource for eyecare professionals.

Ophthalmic Findings and Their Effect on Visual Function in Persons with Albinism in Southern Nigeria

Aim: To determine the pattern of ocular disorders in persons with albinism and how they affect visual function.&#x0D; Methods: This was a descriptive cross-sectional study conducted over a five-month period on persons living with albinism in Southern Nigeria. The study participants were randomly selected during the monthly meetings of a support group known as The Albinism Foundation (TAF).Visual acuity and contrast sensitivity were assessed using the ETDRS visual acuity chart and Pelli Robson contrast sensitivity test chart. A comprehensive eye examination including dilated fundoscopy was also carried out to determine other ocular disorders. Data was analyzed using SPSS version 22 and statistical significance was set at a p-value ≤ 0.05.&#x0D; Results: A total of 116 PWA (232 eyes) were examined. There were 44 (37.9%) males and 72 (62.1%) females. The age of the study subjects ranged from 5 to 56 years. Most eyes were visually impaired for both distance (n=228; 98.3%) and near vision (n= 224; 96.6%). Contrast sensitivity in most eyes (n=138; 59.5%) was subnormal. With refraction and Low Vision Aid (LVA), there was significant improvement of the mean VA by 2-3 acuity lines and 6 acuity lines respectively (p=0.000). All the examined eyes had fundus hypo-pigmentation, 91.4% (n=212) had iris trans-illumination, 86.2% (n=200) had nystagmus, and 34.4% (n=80) had strabismus. Nystagmus, strabismus and iris trans-illumination significantly (p=0.00) reduced visual acuity and contrast sensitivity.&#x0D; Conclusion: Most study participants had reduced distance visual acuity and contrast sensitivity but with correction there was a significant improvement in vision. The presence of nystagmus, strabismus and iris trans-illumination were observed to contribute to the poor vision experienced by most persons living with albinism. Hence, early optical intervention and counselling is important in improving the quality of living of persons with albinism.

Longitudinal study of visual function in patients with relapsing-remitting multiple sclerosis with and without a history of optic neuritis

IntroductionThe contrast sensitivity test determines the quality of visual function in patients with multiple sclerosis (MS). The purpose of this study is to analyse changes in visual function in patients with relapsing-remitting MS with and without a history of optic neuritis (ON). MethodsWe conducted a longitudinal study including 61 patients classified into 3 groups as follows: (a) disease-free patients (control group); (b) patients with MS and no history of ON; and (c) patients with MS and a history of unilateral ON. All patients underwent baseline and 6-year follow-up ophthalmologic examinations, which included visual acuity and monocular and binocular Pelli-Robson contrast sensitivity tests. ResultsMonocular contrast sensitivity was significantly lower in MS patients with and without a history of ON than in controls both at baseline (P=.00 and P=.01, respectively) and at 6 years (P=.01 and P=.02). Patients with MS and no history of ON remained stable throughout follow-up whereas those with a history of ON displayed a significant loss of contrast sensitivity (P=.01). Visual acuity and binocular contrast sensitivity at baseline and at 6 years was significantly lower in the group of patients with a history of ON than in the control group (P=.003 and P=.002 vs P=.006 and P=.005) and the group with no history of ON (P=.04 and P=.038 vs P=.008 and P=.01). However, no significant differences were found in follow-up results (P=.1 and P=.5). ConclusionsMonocular Pelli-Robson contrast sensitivity test may be used to detect changes in visual function in patients with ON.

Multiple Sensory Impairment Is Associated With Increased Risk of Dementia Among Black and White Older Adults.

Few studies have examined impairment in multiple senses (multisensory impairment) and risk of dementia in comparison to having a single or no sensory impairment. We studied 1,810 black and white nondemented participants from Health, Aging, and Body Composition (Health ABC) Study aged 70-79 years at enrollment. Sensory impairment was determined at our study baseline (Year 3-5 of Health ABC) using established cut points for vision (Bailey-Lovie visual acuity and Pelli-Robson contrast sensitivity test), hearing (audiometric testing), smell (12-item Cross-Cultural Smell Identification Test), and touch (peripheral nerve function tests). Incident dementia over 10 years of follow-up was based on hospitalization records, dementia medications, or at least 1.5 SD decline in Modified Mini-Mental State Examination score (race-specific). Cox proportional hazard models with adjustment for demographics, health behaviors, and health conditions evaluated the relationship between risk of dementia and increasing number of sensory impairments. Sensory impairments were common: 28% had visual impairment, 35% had hearing loss, 22% had poor smell, 12% had touch insensitivity; 26% had more than two impairments, and 5.6% had more than three sensory impairments. Number of impairments was associated with risk of dementia in a graded fashion (p < .001). Compared to no sensory impairments, the adjusted hazard ratio was 1.49 (95% CI: 1.12, 1.98) for one sensory impairment, 1.91 (95% CI: 1.39, 2.63) for two sensory impairments, and 2.85 (95% CI: 1.88, 4.30) for more than three sensory impairments. Multisensory impairment was strongly associated with increased risk of dementia. Although, the nature of this relationship needs further investigation, sensory function assessment in multiple domains may help identify patients at high risk of dementia.

Multifocal visual evoked potentials and contrast sensitivity correlate with ganglion cell-inner plexiform layer thickness in multiple sclerosis

ObjectiveTo examine the relationship between optical coherence tomography (OCT) macular ganglion cell-inner plexiform layer thickness (GCIPLT), peripapillary retinal nerve fiber layer thickness (RNFLT) and visual function in relapsing-remitting multiple sclerosis (RRMS). MethodsCirrus OCT, VERIS 60-sector multifocal visual evoked potential (mfVEP) and Pelli-Robson contrast sensitivity (CS) were obtained for 53 eyes with last optic neuritis (ON) > 6 months and 105 non-ON eyes in 90 patients. One eye (43 ON, 73 non-ON) was used for correlations when both had the same history. Global (G, 60 sectors) and central 5.6° (C, 24 sectors) mfVEP amplitude and latency were calculated as mean logSNR and median latency. ResultsEyes showing abnormal mfVEP (amplitude or latency) vs OCT (GCIPLT or RNFLT) was 77% vs 69% (p = 0.33) in ON, 45% vs 22% (p < 0.0005) in non-ON. In ON and non-ON, mfVEP measures and CS correlated with GCIPLT and RNFLT (r = −0.24 to 0.78, p = 0.03–0.0001). In ON, mfVEP amplitude (C,G) correlated better with GCIPLT (r = 0.78, 0.76) than RNFLT (r = 0.43, 0.58; p < 0.001, 0.01). ConclusionsMfVEP measures and CS correlated well with GCIPLT and RNFLT in ON and non-ON. MfVEP amplitudes were more highly correlated with GCIPLT than RNFLT in ON. MfVEP detected significantly more defects than OCT in non-ON. SignificanceGCIPLT, mfVEP and CS provide useful measures of optic nerve integrity in RRMS.

Subjective and Objective Measures of Daytime Activity and Sleep Disturbance in Retinitis Pigmentosa.

Objectively measured limitations in daytime activity levels appear to be inextricably linked with sleep disturbances in retinitis pigmentosa (RP) patients, as well as associated with unemployment status and central vision loss. Innovative interventional strategies should be developed to help improve these issues and overall quality of life for RP patients. Novel sensor devices are emerging as valuable tools to objectively assess behavior. We used validated measures of wrist accelerometry to determine relationships between sleep, vision, and physical activity in RP subjects. For one week, 33 RP adults wore a wrist Actiwatch to detect movement during the day (average total activity counts) and disturbed sleep at night. They completed Early Treatment Diabetic Retinopathy Study visual acuity testing, Pelli-Robson contrast sensitivity, Goldmann V4e visual fields, and sleep diaries and validated questionnaires to assess their sleep and general health. Greater wake after sleep onset time measured with actigraphy (i.e., sleep disruption) (P = .01), loss of visual acuity (P = .009), and nonemployment/student status (P = .002) were all significant predictors of reduced daytime average total activity counts in a multiple linear regression model, after adjusting for contrast sensitivity as a cooperative suppressor variable (P = .01) (R = 0.54). Fragmentation measured with actigraphy (i.e., restlessness during sleep) (P = .07) and decreased sleep quality ratings reported upon awakening by the participants in a sleep diary (P = .06) were each marginally associated with reduced daytime average total activity counts, whereas nonemployment/student status, reduced visual acuity, and contrast sensitivity were still significant predictors. Objective and subjective measures of sleep or daytime activity were not statistically significantly correlated (P > .05). We find nonemployment/student status and sleep disturbances appear to be related to reduced daytime activity levels in adults with central vision loss due to RP. These findings underscore the importance of developing and evaluating interventions to help RP patients maintain engagement in productive activities and improve their disturbed sleep.

Evaluation of contrast sensitivity and other visual function outcomes in diabetic macular edema patients following treatment switch to aflibercept from ranibizumab.

PurposeThis study aims to investigate changes in contrast sensitivity (CS), visual acuity (VA), central retinal thickness (CRT), and vision-related quality of life in subjects with recalcitrant diabetic macular edema switched from long-term ranibizumab treatment to aflibercept.Patients and methodsIn this prospective, investigator-masked, single-center study, 40 patients with persistent fluid, despite previous ranibizumab treatment, were switched to aflibercept with 5 consecutive monthly doses. The primary outcome was mean change from baseline to week 20 in Pelli–Robson CS. Secondary outcomes were mean change from baseline in best-corrected VA (BCVA), CRT, and National Eye Institute 25-Item Visual Function Questionnaire score.ResultsFifty eyes (baseline VA >6/30) were evaluated. A median of 21.1±11.9 (range 5–55) ranibizumab injections were administered prior to initiation of aflibercept. Mean CS improved from 1.40±0.14 log units at baseline to 1.46±0.15 log units at week 20 (P<0.001). VA improved with mean logarithm of the minimum angle of resolution BCVA of 0.33±0.19 at baseline compared with logarithm of the minimum angle of resolution BCVA of 0.28±0.16 at week 20 (P=0.0016). Mean CRT decreased from 324±85 to 289±61 µm (P<0.001). Twenty-two (55%) patients experienced an overall improvement in National Eye Institute 25-Item Visual Function Questionnaire score. Interestingly, an association was found between changes in CS and change in CRT (r2=0.385, P<0.001) and between changes in BCVA and change in CRT (r2=0.092, P=0.032).ConclusionSwitching from ranibizumab to aflibercept in patients with recalcitrant diabetic macular edema resulted in an improvement in all measured metrics, including CS, VA, and CRT. A majority of patients also indicated an improvement in vision-related quality of life. The finding of a stronger relationship between changes in CRT and CS compared with changes in CRT and BCVA suggests that the inclusion of CS as an endpoint may yield a more complete understanding of visual outcomes than that obtained by using VA alone.

Seeing it differently: self-reported description of vision loss in dry age-related macular degeneration.

A realistic description of visual symptoms associated with dry age-related macular degeneration (AMD) is important for raising awareness of the condition and educating patients. This study aimed to develop a set of descriptors for dry AMD and examine the realism of images currently and frequently used to show visual symptoms of the condition. Volunteers with dry AMD with a range of disease severity were given an eye examination and were asked to describe visual symptoms of their condition in a conversational interview. Participants were also asked to comment on a photograph typically used to portray the visual symptoms of AMD. Interviews were audio recorded, transcribed and subjected to content analysis. Twenty-nine participants were interviewed. Median (interquartile range [IQR]) age was 75 (70, 79) years. Median (IQR) binocular visual acuity (VA) and Pelli-Robson contrast sensitivity (CS) was 0.2 (0.18, 0.36) logMAR and 1.65 (1.50, 1.95) log CS respectively. Three, 17 and nine patients had early, intermediate and late (geographic atrophy, GA) AMD, respectively. The most frequently reported descriptor group was blur (n=13) followed by missing (n=10) and distortion (n=7). We chose the most popular image used to portray the visual symptoms of dry AMD based on an internet search and showed this to 21 participants. Sixteen participants (76% [95% confidence interval 53-92%]), including three out of the seven people with geographic atrophy, unequivocally rejected the realism of the image. People with dry AMD use a wide range of descriptors for their visual experience. Visual symptoms of dry AMD as portrayed by commonly shown images were not the experience of most people in this study.

The Ohio Contrast Cards: Visual Performance in a Pediatric Low-vision Site.

This report describes the first clinical use of the Ohio Contrast Cards, a new test that measures the maximum spatial contrast sensitivity of low-vision patients who cannot recognize and identify optotypes and for whom the spatial frequency of maximum contrast sensitivity is unknown. To compare measurements of the Ohio Contrast Cards to measurements of three other vision tests and a vision-related quality-of-life questionnaire obtained on partially sighted students at Ohio State School for the Blind. The Ohio Contrast Cards show printed square-wave gratings at very low spatial frequency (0.15 cycle/degree). The patient looks to the left/right side of the card containing the grating. Twenty-five students (13 to 20 years old) provided four measures of visual performance: two grating card tests (the Ohio Contrast Cards and the Teller Acuity Cards) and two letter charts (the Pelli-Robson contrast chart and the Bailey-Lovie acuity chart). Spatial contrast sensitivity functions were modeled using constraints from the grating data. The Impact of Vision Impairment on Children questionnaire measured vision-related quality of life. Ohio Contrast Card contrast sensitivity was always less than 0.19 log10 units below the maximum possible contrast sensitivity predicted by the model; average Pelli-Robson letter contrast sensitivity was near the model prediction, but 0.516 log10 units below the maximum. Letter acuity was 0.336 logMAR below the grating acuity results. The model estimated the best testing distance in meters for optimum Pelli-Robson contrast sensitivity from the Bailey-Lovie acuity as distance = 1.5 - logMAR for low-vision patients. Of the four vision tests, only Ohio Contrast Card contrast sensitivity was independently and statistically significantly correlated with students' quality of life. The Ohio Contrast Cards combine a grating stimulus, a looking indicator behavior, and contrast sensitivity measurement. They show promise for the clinical objective of advising the patient and his/her caregivers about the success the patient is likely to enjoy in tasks of everyday life.

Simple Single-Pass Technique for Ultrathin Descemet Stripping Automated Endothelial Keratoplasty: A Pilot Study.

To assess intraoperative and postoperative graft thickness (GT) after donor deturgescence for ultrathin Descemet stripping automated endothelial keratoplasty and to evaluate visual outcomes, endothelial cell density, and patient satisfaction at 1 year. Prospective interventional case series of patients with Fuchs endothelial dystrophy, Fuchs endothelial dystrophy and cataract, and pseudophakic bullous keratopathy (n = 12 grafts). The donor cornea was allowed to thin out by simple evaporation on an artificial anterior chamber, to the required precut thickness, before a single microkeratome pass. GT after microkeratome cut, at 1 week, 1, 3, 6, and 12, months was measured. Early Treatment Diabetic Retinopathy Study (ETDRS) best-corrected visual acuity, Pelli-Robson contrast sensitivity, endothelial cell density, and score on the visual function questionnaire (VFQ-25) were assessed. Mean intraoperative postmicrokeratome cut GT was 78.9 ± 33.3 μm. Mean GT at 1 week, 1, 3, 6, and 12 months was 70.7, 70.9, 62.8, 66.5, and 58.9 μm, respectively. Mean initial donor corneal thickness was 647 ± 67 μm, and mean precut thickness was 526 ± 4.5 μm (mean thinning time: 17 min). Best-corrected visual acuity at 1 week, 1, 3, 6, and 12 months was 68.8, 76.9, 76.3, 76.9, and 78.6 letters with 9-letter gain at 12 months (P = 0.02). Mean endothelial cell loss at 3, 6, and 12 months was 36.8% ± 6.75%, 37.2% ± 8%, and 37.9% ± 9.75% loss, respectively. At 1 year, 83.3% of patients achieved ≥20/40 (6/12) and 66.7% of patients achieved ≥20/32 (6/9.5). VFQ-25 testing showed an improvement in the visual function. This pilot study demonstrates a simple graft deturgescence technique that reproducibly creates ultrathin grafts without donor wastage.

Evaluation of contrast sensitivity and other visual function outcomes in neovascular age-related macular degeneration patients after treatment switch to aflibercept from ranibizumab.

PurposeThis study evaluated visual function and anatomic and vision-related quality-of-life outcomes in recalcitrant neovascular age-related macular degeneration (AMD) subjects switched to aflibercept (Eylea®) from ranibizumab (Lucentis®).MethodsIn a single-center study conducted in Barrie, ON, 40 patients with persistent fluid despite previous ranibizumab treatment were switched to aflibercept with 3 consecutive monthly doses. Main outcome measure was mean change from baseline to week 12 in Pelli–Robson contrast sensitivity (CS). Secondary outcomes were mean change in best corrected visual acuity (BCVA), central retinal thickness (CRT), and National Eye Institute 25-Item Visual Function Questionnaire (NEI VFQ-25) score. A two-sided paired t-test was used in the statistical data analysis to compare the means of continuous variables.ResultsForty-nine eyes (baseline visual acuity [VA] >6/120) were evaluated. Ranibizumab injections (mean ± standard deviation [SD] 28.2±22.1 [range 3–86]) were administered prior to treatment switch. Mean CS improved from 1.32 at baseline to 1.40 log units at week 12. VA was stable throughout. Mean CRT decreased from 354 µm at baseline to 332 µm at week 12 (−22 µm, P=0.004). Twenty-six (65%) patients experienced an overall improvement in NEI VFQ-25 score. Interestingly, a correlation was observed between improvement in log CS and CRT change (P=0.000046).ConclusionContrast sensitivity improved statistically and significantly, and CRT decreased from baseline to week 12 after a switch to aflibercept from ranibizumab. Analysis of CS as an independent outcome end point in neovascular AMD treatment switch studies may provide a more complete understanding of visual response.

Estudio longitudinal de la función visual en pacientes con esclerosis múltiple remitente-recurrente con y sin antecedentes de neuritis óptica

IntroductionThe contrast sensitivity test determines the quality of visual function in patients with multiple sclerosis (MS). The purpose of this study is to analyse changes in visual function in patients with relapsing-remitting MS with and without a history of optic neuritis (ON). MethodsWe conducted a longitudinal study including 61 patients classified into 3 groups as follows: a) disease-free patients (control group); b) patients with MS and no history of ON; and c) patients with MS and a history of unilateral ON. All patients underwent baseline and 6-year follow-up ophthalmologic examinations, which included visual acuity and monocular and binocular Pelli-Robson contrast sensitivity tests. ResultsMonocular contrast sensitivity was significantly lower in MS patients with and without a history of ON than in controls both at baseline (P=.00 and P=.01, respectively) and at 6 years (P=.01 and P=.02). Patients with MS and no history of ON remained stable throughout follow-up whereas those with a history of ON displayed a significant loss of contrast sensitivity (P=.01). Visual acuity and binocular contrast sensitivity at baseline and at 6 years was significantly lower in the group of patients with a history of ON than in the control group (P=.003 and P=.002 vs P=.006 and P=.005) and the group with no history of ON (P=.04 and P=.038 vs P=.008 and P=.01). However, no significant differences were found in follow-up results (P=.1 and P=.5). ConclusionsMonocular Pelli-Robson contrast sensitivity test may be used to detect changes in visual function in patients with ON.

Effects of Monocular Blur on Clinical Measurements of Stereopsis and Binocular Contrast Sensitivity

Visual conditions such as anisometropia, monovision and monocular undercorrection affect the combination of visual input from both eyes. This study investigated the effects of monocular blur, in binocularly normal participants, on stereoacuity and binocular contrast sensitivity. Fifteen young adults (age range between 19 and 23 years old) with normal visual acuity and binocular vision participated in this study. Stereopsis was measured using the TNO test with a series of positive spherical lenses placed before the dominant eye. The procedure was repeated using the Titmus Stereotest on five participants as a control experiment. Monocular and binocular contrast sensitivities were also measured using the Pelli-Robson Contrast Sensitivity Chart. Blur was induced monocularly with a series of positive spherical lenses placed before the dominant eye and binocular contrast sensitivity was re-measured. Stereopsis scores decreased significantly when monocular blur was imposed. Across blur levels, absolute stereopsis scores measured with TNO test were worse than those measured with Titmus stereotest (all p < 0.05). However, the ratio of scores obtained without blur and under monocular blur appeared to be similar for both tests. Stereopsis without blur was between 6.82× to 8× better than that obtained with the highest level of imposed monocular blur. Binocular contrast sensitivity score decreased significantly with increasing level of monocular blur (p < 0.01). Binocular contrast sensitivity score without blur was 1.62× better than that obtained under binocular viewing with highest level of imposed blur. Stereopsis tests are more sensitive than measurements of binocular contrast sensitivity as an indicator of interocular acuity discrepancies which could occur in anisometropic or monovision patients. However, the choice of stereopsis test is crucial, as the TNO test appears to be more sensitive to monocular blur than the Titmus stereostest. DOI: http://dx.doi.org./10.17576/JSKM-2017-1501-03

SPARCS and Pelli–Robson contrast sensitivity testing in normal controls and patients with cataract

PurposeTo determine the ability of the newly developed internet-based Spaeth/Richman Contrast Sensitivity (SPARCS) test to assess contrast sensitivity centrally and peripherally in cataract subjects and controls, in comparison with the Pelli-Robson (PR) test.MethodsIn this prospective cross-sectional study, cataract subjects and age-matched normal controls were evaluated using the SPARCS and PR tests. Contrast sensitivity testing was performed in each eye twice in a standardized testing environment in randomized order. SPARCS scores were obtained for central, right upper (RUQ), right lower (RLQ), left upper (LUQ), and left lower quadrants (LLQ). PR scores were obtained for central contrast sensitivity. PR and SPARCS scores in cataract subjects were compared with controls. Intraclass correlation coefficients (ICC) and Bland Altman analysis were used to determine test-retest reliability and correlation.ResultsA total of 162 eyes from 84 subjects were analyzed: 43 eyes from 23 cataract subjects, and 119 eyes from 61 controls. The mean scores for SPARCS centrally were 13.4 and 14.5 in the cataract and control groups, respectively (P=0.001). PR mean scores were 1.31 and 1.45 in cataract and control groups, respectively (P<0.001). ICC values for test-retest reliability for cataract subjects were 0.75 for PR and 0.61 for the SPARCS total. There was acceptable agreement between the ability of PR and SPARCS to detect the effect of cataract on central contrast sensitivity.ConclusionsBoth SPARCS and PR demonstrate a significant influence of cataract on contrast sensitivity. SPARCS offers the advantage of determining contrast sensitivity peripherally and centrally, without being influenced by literacy.

Quantitative visual tests after poorly recovered optic neuritis due to multiple sclerosis

BackgroundVisual dysfunction in MS can be quantified using a variety of tests. Many vision tests have not been formally evaluated among MS patients with existing visual dysfunction. ObjectiveEvaluate several versions of visual acuity and contrast sensitivity tests, measures of central and peripheral vision, retina structure, electrophysiologic function, and quality of life among MS patients with moderate/severe visual dysfunction. MethodsCross-sectional study of 46 patients with stable, incompletely recovered optic neuritis. Testing included Snellen eye charts, several Sloan low contrast charts, Pelli Robson (PR) contrast sensitivity charts, optical coherence tomography, visual fields, Farnsworth Munsell 100-hue test, visual evoked potentials (VEP), and visual function quality of life (VFQ-25) testing. Results98% of eyes could read two lines of the PR chart, while only 43% read the 2.5% contrast chart. Low contrast tests correlated strongly with each other and with retinal nerve fiber layer (RNFL) thickness, visual fields, and color vision but not with VEPs. For patients with RNFL <75µm, VFQ-25 scores dropped by approximately 2 points for every 1µm decrease in RNFL. ConclusionAmong MS patients with visual impairment due to optic neuritis, PR contrast sensitivity could be utilized as a single chart. Visual quality of life was associated with RNFL thinning below 75µm.

Performance, usability and comparison of two versions of a new macular vision test: the handheld Radial Shape Discrimination test.

BackgroundCentral vision, critical for everyday tasks such as reading and driving, is impacted by age-related changes in the eye and by diseases such as age-related macular degeneration. The detection of changes in macular function is therefore important. The Radial Shape Discrimination (RSD) test measures the threshold at which distortions in a radial frequency pattern can be detected and there is evidence that it is more sensitive to macular pathology than visual acuity (VA). It also provides a more quantitative measure of macular function than the commonly available Amsler grid. Recently, handheld versions of the test (hRSD) in which stimuli are presented on mobile devices (e.g., Apple iPod Touch, iPhone) have been developed. We investigated the characteristics of the hRSD test in healthy participants.MethodsData were collected using both three-alternative forced choice (3AFC) and 4AFC versions of the hRSD test, presented on an Apple iPod Touch. For the 3AFC version, data from a single test session were available for 186 (72 male; mean ± SD age 42 ± 17y; range 16–90y) healthy participants. Test-retest data were available for subgroups of participants (intra-session: N = 74; tests approximately 2 months apart: N = 30; tests 39 months apart: N = 15). The 3AFC and 4AFC versions were directly compared in 106 participants who also completed a usability questionnaire. Distance and near VA and Pelli Robson Contrast Sensitivity (CS) data were collected and undilated fundoscopy performed on the majority of participants.ResultsMean (±SD) 3AFC hRSD threshold was −0.77 ± 0.14 logMAR, and was statistically significantly correlated with age (Pearson r = 0.35; p < 0.001). The linear regression of hRSD threshold on age had a slope of +0.0026 compared to +0.0051 for near VA (which also correlated with age: r = 0.51; p < 0.001). There were no statistically significant differences in hRSD thresholds for any of the test-retest subgroups. We also observed no statistically significant difference between 3AFC (−0.82 ± 0.11 logMAR) and 4AFC (−0.80 ± 0.12 logMAR) hRSD thresholds (t = 1.85, p = 0.067) and participants reported excellent test usability with no strong preference expressed between the 3AFC and 4AFC versions of the test.DiscussionThe 3AFC hRSD thresholds we report are consistent with a number of previous studies, as is its greater stability in ageing compared to VA. We have also shown that in the absence of pathology, thresholds are stable over short and long timescales. The 4AFC thresholds we have reported provide a baseline for future investigations, and we have confirmed that 3AFC and 4AFC thresholds are similar, providing a basis of comparisons between studies using the different versions. As the hRSD test is easy to use and relatively inexpensive, clinical studies are now required to establish its ability to detect and monitor macular pathologies.

Age-Related Sensory Impairments and Risk of Cognitive Impairment.

To evaluate the associations between sensory impairments and 10-year risk of cognitive impairment. The Epidemiology of Hearing Loss Study (EHLS), a longitudinal, population-based study of aging in the Beaver Dam, Wisconsin community. Baseline examinations were conducted in 1993 and follow-up examinations have been conducted every 5 years. General community. EHLS members without cognitive impairment at EHLS-2 (1998-2000). There were 1,884 participants (mean age 66.7) with complete EHLS-2 sensory data and follow-up information. Cognitive impairment was defined as a Mini-Mental State Examination score of <24 or history of dementia or Alzheimer's disease. Hearing impairment was a pure-tone average of hearing thresholds (0.5, 1, 2, 4 kHz) of >25 dB hearing level in either ear, visual impairment was a Pelli-Robson contrast sensitivity of <1.55 log units in the better eye, and olfactory impairment was a San Diego Odor Identification Test score of <6. Hearing, visual, and olfactory impairment were independently associated with cognitive impairment risk (hearing: hazard ratio (HR) = 1.90, 95% confidence interval (CI) = 1.11-3.26; vision: HR = 2.05, 95% CI = 1.24-3.38; olfaction: HR = 3.92, 95% CI = 2.45-6.26)). Nevertheless, 85% of participants with hearing impairment, 81% with visual impairment, and 76% with olfactory impairment did not develop cognitive impairment during follow-up. The relationship between sensory impairment and cognitive impairment was not unique to one sensory system, suggesting that sensorineural health may be a marker of brain aging. The development of a combined sensorineurocognitive measure may be useful in uncovering mechanisms of healthy brain aging.