Assessment of Visual Performance in Patients With Low Levels of Astigmatism

Completed

• Conditions: Cataract Extraction; Corneal Astigmatism
• Interventions: Other: Visual performance measures

• Registration Number: NCT00842231
• Lead Sponsor: Alcon Research

Brief Summary

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

Detailed Description

Not available

Study Timeline

• Study Start: 2009-01
• Study First Submitted: 2009-02-11
• Study First Submitted QC: 2009-02-11
• Study First Posted: 2009-02-12
• Primary Completion: 2009-03
• Results First Submitted: 2010-08-11
• Results First Submitted QC: 2010-08-11
• Status Verified: 2010-09
• Results First Posted: 2010-09-08
• Last Update Submitted: 2010-09-23
• Last Update Posted: 2010-09-28

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 40

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

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
Visual performance measures	Visual performance measures	Collection of visual performance measures in subjects with low levels of astigmatism.

Primary Outcome Measures

Name	Time	Method
High and Low Contrast Acuity	Day of study visit	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).
Contrast Sensitivity	Day of Study Visit	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.
Reading Acuity and Speed	Day of Study Visit	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).

Trial Locations

Locations (1)

Contact Alcon Call Center For Trial Locations; 🇺🇸 Fort Worth, Texas, United States