Assessment of Visual Performance in Patients With Low Levels of Astigmatism

Corneal Astigmatism Clinical Trial

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT00842231
• Other study ID #: P-08-06
• Status: Completed
• Phase: N/A
• First received: February 11, 2009
• Last updated: September 23, 2010
• Start date: January 2009

Study information

• Verified date: September 2010
• Source: Alcon Research
• Contact: n/a
• Is FDA regulated: No
• Health authority: United States: Institutional Review Board
• Study type: Observational

Clinical Trial Summary

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

Recruitment information / eligibility

• Status: Completed
• Enrollment: 40
• Est. primary completion date: March 2009
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Both
• Age group: 50 Years to 75 Years

Eligibility

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

Observational Model: Cohort, Time Perspective: Prospective

Related Conditions & MeSH terms

• Astigmatism
• Cataract Extraction
• Corneal Astigmatism

Intervention

Other:
• Visual performance measures
Collection of visual performance measures in subjects with low levels of astigmatism.

Locations

Country	Name	City	State
United States	Contact Alcon Call Center For Trial Locations	Fort Worth	Texas

Sponsors (1)

Lead Sponsor	Collaborator
Alcon Research

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	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	No
Primary	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	No
Primary	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	No