Assessment of Visual Performance in Patients With Low Levels of Astigmatism

September 23, 2010 updated by: Alcon Research
To assess visual performance in patients with low levels (0.5-0.75 Diopters) of corneal astigmatism.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Observational

Enrollment (Actual)

40

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Texas
      • Fort Worth, Texas, United States, 76134
        • Contact Alcon Call Center for Trial Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

50 years to 75 years (ADULT, OLDER_ADULT)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

Subjects were selected from a single investigator's primary care clinic.

Description

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 Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Visual performance measures
Collection of visual performance measures in subjects with low levels of astigmatism.
Other: Visual performance measures
Collection of visual performance measures in subjects with low levels of astigmatism.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
High and Low Contrast Acuity
Time Frame: 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).
Day of study visit
Contrast Sensitivity
Time Frame: 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.
Day of Study Visit
Reading Acuity and Speed
Time Frame: 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).
Day of Study Visit

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Alcon Research

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

January 1, 2009

Primary Completion (ACTUAL)

March 1, 2009

Study Registration Dates

First Submitted

February 11, 2009

First Submitted That Met QC Criteria

February 11, 2009

First Posted (ESTIMATE)

February 12, 2009

Study Record Updates

Last Update Posted (ESTIMATE)

September 28, 2010

Last Update Submitted That Met QC Criteria

September 23, 2010

Last Verified

September 1, 2010

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • P-08-06

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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