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OpenTrials
Completed

NCT Number: NCT00842231

Assessment of Visual Performance in Patients With Low Levels of Astigmatism

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

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Key information

Conditions

Cataract Extraction Astigmatism Corneal Astigmatism Eye Diseases Refractive Errors

Age range

50 year–75 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Contact Alcon Call Center For Trial Locations

Fort Worth, Texas, 76134, United States

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Visual performance measures

Other

Collection of visual performance measures in subjects with low levels of astigmatism.

Primary outcomes

  1. 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).

  2. 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.

  3. 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).

Sponsors and collaborators

Lead sponsor

Alcon Research

Industry

Registry information

Important dates

Study start
2009
Primary completion
2009
First posted
Feb 12, 2009
Registry last updated
Sep 28, 2010

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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