To evaluate the repeatability of macular thickness and total macular volume measurements made using spectral domain optical coherence tomography (OCT) in normal subjects and subjects with macular disease.

Among a total of 108 subjects, there were 50 normal subjucts, 20 patients with diabetic macular edema, 10 patients with retinal vein occlusion, 15 patients with age-related macular degeneration, and 13 subjects with other conditions. Two serial macular measurements were obtained from each subject by a single experienced examiner using spectral domain OCT. The repeatability of the measurements was evaluated by comparing two consecutive foveal and perifoveal thickness measurements and total macular volume measurements. The intraclass correlation coefficient was also calculated to evaluate the repeatability of measurements made in normal and macular disease subjects.

Spectral domain OCT measurements of macular thickness and macular volume were found to be consistent. Measurements of normal subjects were the most consistent, followed by measurements of patients with age-related macular degeneration, retinal vein occlusion, and diabetic macular edema.

Although measurements made using spectral domain OCT were repeatable across all subjects, they were more consistent in normal subjects than in patients with macular disease. The differences in repeatability should be considered in the context of diseased pathologic anatomy. Physicians should remain cautious when using these measurements for clinical evaluation.