The confocal scanning laser ophthalmoscopy ancillary study to the ocular hypertension treatment study: study design and baseline factors☆

Accepted 10 August 2003.

Abstract

Purpose

To describe the study design of the Confocal Scanning Laser Ophthalmoscopy (CSLO) Ancillary Study to the Ocular Hypertension Treatment Study (OHTS) and to examine the associations between optic disk topography, and baseline demographic, clinical, and ocular factors at study entry.

Design

A randomized clinical trial.

Methods

Participants in this ancillary study were recruited from seven of the 22 OHTS clinical centers. Each participant completed imaging annually using a CSLO, the Heidelberg Retina Tomograph (HRT). Associations between HRT topographic optic disk measurements and intraocular pressure (IOP), baseline photographic estimates of horizontal and vertical cup-to-disk diameter ratios by the OHTS Optic Disk Reading Center, baseline visual field indices, and demographic and clinical factors were assessed using linear mixed effects models.

Results

Four hundred thirty-nine participants had good quality images and were included in this baseline analysis. No associations between HRT topographic optic disk measurements and diabetes, systemic hypertension, cardiovascular disease, IOP, or visual function were found. The HRT topographic optic disk measurements were associated with baseline stereophotographic estimates of horizontal and vertical cup-to-disk diameter ratios. The strongest associations were found between stereophotographic assessment of horizontal and vertical cup-to-disk diameter ratios, and HRT cup-to-disk area ratio (r = .85 and .84, respectively), rim-to-disk area ratio (r = −.85 and −.84, respectively), mean cup depth (r = .84 and .83, respectively), and cup area (r = .83 and .80, respectively). After adjusting for optic disk area, all HRT topographic optic disk measurements remained associated with stereophotographic assessment of horizontal and vertical cup-to-disk diameter ratios.

Conclusions

The CSLO ancillary study to the OHTS is the first multicenter clinical trial to use CSLO imaging to monitor changes in the optic disk. At study entry, HRT topographic measurements corresponded well with both horizontal and vertical stereophotographic-based estimates of cup-to-disk diameter ratio in ocular hypertensive participants.

a Departments ofdepartment of Ophthalmology (L.M.Z., R.N.W., A.R.S., K.A.D.), University of California at San Diego, La Jolla, California, USA

b department of Family and Preventive Medicine (C.C.B.), University of California at San Diego, La Jolla, California, USA

c New York Eye and Ear Infirmary (J.M.L.), New York, New York, USA

d University of California at Davis (J.D.B.), Sacramento, California, USA

e Henry Ford Medical Center (G.T.), Troy, Michigan, USA

f Devers Eye Institute (G.A.C.), Portland, Oregon, USA

g Jules Stein Eye Institute (A.L.C.), University of California at Los Angeles, Los Angeles, California, USA

h Scheie Eye Institute (J.R.P.-S.), University of Pennsylvania, Philadelphia, Pennsylvania, USA

i Department of Ophthalmology and Visual Sciences (M.O.G., M.A.K.), Washington University School of Medicine, St. Louis, Missouri, USA

Inquiries to Linda M. Zangwill, PhD, Diagnostic Imaging Laboratory, Hamilton Glaucoma Center and Department of Ophthalmology, University of California, San Diego, 9500 Gilman Dr, La Jolla, CA 92093-0946, USA; fax: (858) 534-1625

☆ This study was supported by Grants EY11158, EY09341, and EY09307 from the National Eye Institute and the National Center of Minority Health and Health Disparities, National Institutes of Health, Bethesda, Maryland; Merck Research Laboratories, White House Station; and by an unrestricted grant from Research to Prevent Blindness, New York, New York. The authors have received support from the following companies: R.N.Weinreb: consultant or honoraria from Alcon and Novartis; consultant or honoraria and grant support or patent received/pending from Allergan Therapeutics, Heidelberg Engineering, Humphrey Instruments, Merck Research Laboratories, and Pharmacia/Upjohn; owns stock in Merck. J. M. Liebmann: consultant or honoraria from Allergan Therapeutics, Heidelberg Engineering, Novartis, and Pharmacia/Upjohn. J. D. Brandt: consultant or honoraria from Allergan, Merck, and Pharmacia/Upjohn. G. A. Cioffi: consultant or honoraria from Merck, Alcon Laboratories; consultant or honoraria and grant support/patent from Allergan, Ciba Vision, Heidelberg Engineering, Humphrey Instruments, Novartis, and Pharmacia/Upjohn. A. L. Coleman: grant support from Alcon Laboratories, consultant or honoraria from Allergan Therapeutics and Pharmacia/Upjohn. J. R. Piltz-Seymour: consultant or honoraria from Alcon, Allergan, Merck, and Pharmacia/Upjohn. M. A. Kass: consultant or honoraria from Merck and Pharmacia/Upjohn. L. M. Zangwill: research support (equipment) from Heidelberg Engineering, Laser Diagnostic Technologies, and Carl Zeiss Meditec.

PII: S0002-9394(03)00969-3

doi:10.1016/j.ajo.2003.08.031

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