Assessment of Visual Performance in Patients With Low Levels of Astigmatism

• Sponsor: Alcon Research (Industry)
• Overall Status: Completed
• CT.gov ID: NCT00842231
• Collaborator: (none)
• Enrollment: 40
• Location: 1

Study Details

Study Description

Brief Summary

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

Condition or Disease	Intervention/Treatment	Phase
Cataract Extraction; Corneal Astigmatism	Other: Visual performance measures

Study Design

• Study Type: Observational
• Actual Enrollment: 40 participants
• Observational Model: Cohort
• Time Perspective: Prospective
• Study Start Date: Jan 1, 2009
• Actual Primary Completion Date: Mar 1, 2009

Arms and Interventions

Arm	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.

Outcome Measures

Primary Outcome Measures

1. 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).

2. 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.

3. 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).

Eligibility Criteria

Criteria

• Ages Eligible for Study: 50 Years to 75 Years
• Sexes Eligible for Study: All
• Accepts Healthy Volunteers: Yes

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

Contacts and Locations

Locations

	Site	City	State	Country	Postal Code
1	Contact Alcon Call Center For Trial Locations	Fort Worth	Texas	United States	76134

Sponsors and Collaborators

• Alcon Research

Investigators

None specified.

Study Documents (Full-Text)

None provided.

More Information

Publications

None provided.

• ClinicalTrials.gov Identifier: NCT00842231
• Other Study ID Numbers: P-08-06
• First Posted: Feb 12, 2009
• Last Update Posted: Sep 28, 2010
• Last Verified: Sep 1, 2010

• Keywords provided by , ,: Corneal astigmatism; post-cataract surgery; visual performance; Corneal astigmatism 0.5-0.75 Diopter
• Additional relevant MeSH terms: Cataract; Astigmatism

Study Results

Participant Flow

Arm/Group Title	Visual Performance Measures
Arm/Group Description	Collection of visual performance measures in subjects with low levels of astigmatism.
Period Title: Overall Study
STARTED	40
COMPLETED	40
NOT COMPLETED	0

Baseline Characteristics

Arm/Group Title	Visual Performance Measures
Arm/Group Description	Collection of visual performance measures in subjects with low levels of astigmatism.
Overall Participants	40
Age, Customized (Number) [Number]
Number [Participants]	40 100%
Sex: Female, Male (Count of Participants)
Female	24 60%
Male	16 40%

Outcome Measures

1. Primary Outcome

Title	High and Low Contrast Acuity
Description	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).
Time Frame	Day of study visit

Outcome Measure Data

Analysis Population Description

Data was collected for 40 eyes in 40 subjects. Only one operative eye of each subject was included in the study. If both eyes qualified, the dominant eye was selected.

Arm/Group Title	Visual Performance Measures
Arm/Group Description	Collection of visual performance measures in subjects with low levels of astigmatism.
Measure Participants	40
9% Contrast Acuity	0.0855 (0.1111)
25% Contrast Acuity	0.065 (0.1019)
100% Contrast Acuity	0.082 (0.1013)

2. Primary Outcome

Title	Contrast Sensitivity
Description	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.
Time Frame	Day of Study Visit

Outcome Measure Data

Analysis Population Description

Data was collected for 40 eyes in 40 subjects. Only one operative eye of each subject was included in the study. If both eyes qualified, the dominant eye was selected.

Arm/Group Title	Visual Performance Measures
Arm/Group Description	Collection of visual performance measures in subjects with low levels of astigmatism.
Measure Participants	40
Mesopic 3 cycles per degree (cpd)	-0.047 (0.2917)
Mesopic 6 cpd	0.0896 (0.3575)
Mesopic 9 cpd	0.0038 (0.3597)
Mesopic 12 cpd	-0.009 (0.371)
Mesopic with glare 3 cpd	0.0176 (0.2271)
Mesopic with glare 6 cpd	0.0241 (0.3146)
Mesopic with glare 9 cpd	0.0183 (0.2728)
Mesopic with glare 12 cpd	0.0669 (0.2559)
Photopic 3 cpd	0.0163 (0.2257)
Photopic 6 cpd	0.0181 (0.2539)
Photopic 9 cpd	0.0479 (0.3866)
Photopic 12 cpd	0.0321 (0.3215)

3. Primary Outcome

Title	Reading Acuity and Speed
Description	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).
Time Frame	Day of Study Visit

Outcome Measure Data

Analysis Population Description

Data was collected for 40 eyes in 40 subjects. Only one operative eye of each subject was included in the study. If both eyes qualified, the dominant eye was selected.

Arm/Group Title	Visual Performance Measures
Arm/Group Description	Collection of visual performance measures in subjects with low levels of astigmatism.
Measure Participants	40
logRAD Line -0.1	2.7469
logRAD Line 0	7.3292
logRAD Line 0.1	11.7498
logRAD Line 0.2	17.5404
logRAD Line 0.3	10.1643
logRAD Line 0.4	13.4166
logRAD Line 0.5	12.7487
logRAD Line 0.6	11.9005
logRAD Line 0.7	15.1714
logRAD Line 0.8	9.7203
logRAD Line 0.9	11.4863
logRAD Line 1.1	16.4043
logRAD Line 1.2	8.8952

Adverse Events

Adverse Event Reporting Description	This study consisted of a single visit on a single day. No adverse event data were collected.
Arm/Group Title	Visual Performance Measures
Arm/Group Description	Collection of visual performance measures in subjects with low levels of astigmatism.
All Cause Mortality
	Visual Performance Measures
	Affected / at Risk (%)	# Events
Total	/ (NaN)
Serious Adverse Events
	Visual Performance Measures
	Affected / at Risk (%)	# Events
Total	0/0 (NaN)
Other (Not Including Serious) Adverse Events
	Visual Performance Measures
	Affected / at Risk (%)	# Events
Total	0/0 (NaN)

Limitations/Caveats

[Not Specified]

More Information

Certain Agreements

Principal Investigators are NOT employed by the organization sponsoring the study.

No paper that incorporates Sponsor confidential information will be submitted for publication without Sponsor's prior written agreement.