Assessment of Visual Performance in Patients With Low Levels of Astigmatism

Study Overview
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Brief Summary
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To assess visual performance in patients with low levels (0.5-0.75 Diopters) of corneal astigmatism.

Conditions
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Cataract Extraction, Corneal Astigmatism

Intervention / Treatment
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* Other: Visual performance measures


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 50-75 years of age Proof of eye exam within the last 12 months Operated for uncomplicated, age-related cataracts >3 months Corneal astigmatism of 0.5-0.75 diopter Exclusion Criteria: Previous ocular or refractive surgery/trauma Clinically severe corneal dystrophy Amblyopia Degenerative visual disorders

Ages Eligible for Study
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Minimum Age: 50 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Visual performance measures<br>Collection of visual performance measures in subjects with low levels of astigmatism. | Other: Visual performance measures<br>* Collection of visual performance measures in subjects with low levels of astigmatism.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| High and Low Contrast Acuity | Visual acuity differences between subjects tested with full correction and spherical equivalent (SE) correction at contrast levels of 9% and 25% (low contrast acuity) and 100% (high contrast acuity). LogMAR is the logarithm of the minimum angle of resolution. A lower logMAR value indicates better VA. These measurements were performed under photopic conditions by means of 9%, 25%, and 100% contrast ETDRS (Early Treatment Diabetic Retinopathy Study) charts (Vector Vision). | Day of study visit | 
| Contrast Sensitivity | Contrast Sensitivity (CS) differences between subjects tested with full correction & spherical equivalent (SE) correction. CS is the measurement of one's ability to detect slight changes in luminance before it becomes indistinguishable. CS is measured in logarithmic units by means of an illuminated box, the CSV 1000 by Vector Vision. Testing was performed under photopic conditions (no glare) & mesopic conditions (with & without glare), and was measured at four spatial frequencies of 3, 6, 9, and 12 cycles per degree (cpd). A higher value for the logarithmic units translates to better CS. | Day of Study Visit | 
| Reading Acuity and Speed | Reading Acuity and Speed differences between subjects tested with full correction and spherical equivalent (SE) correction. Reading Acuity was measured using the Radner reading charts, which are logarithmically scaled at different acuity levels (print sizes), and expressed in terms of logRAD (logrithmic Reading Acuity Determination). Reading speed was measured in words per minute (wpm). The results were presented as Average Reading Speed by Print Size (logRAD). | Day of Study Visit | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Corneal astigmatism, post-cataract surgery, visual performance, Corneal astigmatism 0.5-0.75 Diopter