Rn. Weinreb et al., EFFECT OF REPETITIVE IMAGING ON TOPOGRAPHIC MEASUREMENTS OF THE OPTIC-NERVE HEAD, Archives of ophthalmology, 111(5), 1993, pp. 636-638
Objective.-A confocal scanning diode laser ophthalmoscope was used to
determine the number of examinations needed to obtain highly reproduci
ble topographic measurements of the optic nerve head and peripapillary
retina. Design.-Topographic images of the optic nerve head and peripa
pillary retina were obtained in one randomly selected eye on five sepa
rate 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 e
lements (65 536 pixels). Setting.-Glaucoma referral center. Subjects.-
Five normal subjects and five patients with glaucoma. Intervention.-To
pographic imaging of the optic nerve head and peripapillary retina. Ma
in Outcome Measure.-Number of examinations needed to obtain highly rep
roducible topographic measurements. Results.-In healthy subjects, repr
oducibility with one examination per visit was 35.5 mum; this improved
to 25.7 mum with three examinations and 22.5 mum with five examinatio
ns. In older patients with glaucoma, the reproducibility improved from
40.2 mum with one examination per visit to 28.5 and 24.1 mum with thr
ee and five examinations, respectively. Conclusion.-We recommend a ser
ies of three examinations to provide high reproducibility with optimal
efficiency in terms of time and materials used.