Effect of repetitive imaging on topographic measurements of the optic nerve head.
OBJECTIVE
A confocal scanning diode laser ophthalmoscope was used to determine the number of examinations needed to obtain highly reproducible topographic measurements of the optic nerve head and peripapillary retina.


METHODS
Topographic images of the optic nerve head and peripapillary retina were obtained in one randomly selected eye on five separate visits. On each occasion the selected eye had five examinations. For each examination, one image was acquired (a total of 25 images per eye). Reproducibility was calculated as the average SD of all image elements (65,536 pixels).


METHODS
Glaucoma referral center.


METHODS
Five normal subjects and five patients with glaucoma.


METHODS
Topographic imaging of the optic nerve head and peripapillary retina.


METHODS
Number of examinations needed to obtain highly reproducible topographic measurements.


RESULTS
In healthy subjects, reproducibility with one examination per visit was 35.5 microns; this improved to 25.7 microns with three examinations and 22.5 microns with five examinations. In older patients with glaucoma, the reproducibility improved from 40.2 microns with one examination per visit to 28.5 and 24.1 microns with three and five examinations, respectively.


CONCLUSIONS
We recommend a series of three examinations to provide high reproducibility with optimal efficiency in terms of time and materials used.
Weinreb
R N
RN
Department of Ophthalmology, University of California, San Diego.
Lusky
M
M
Bartsch
D U
DU
Morsman
D
D
D000328:Adult; D000368:Aged; D005901:Glaucoma / Q000175:diagnosis*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D007429:Intraocular Pressure; D008875:Middle Aged; D009887:Ophthalmoscopy / Q000379:methods; D009898:Optic Disk / Q000473:pathology*; D011897:Random Allocation; D015203:Reproducibility of Results; D012160:Retina / Q000473:pathology