This article is more than 5 years old. Information may no longer be current.
Study offers guidelines for diagnosing glaucoma with time-domain OCT
J Glaucoma. 2011;20(3):133-138.
Click Here to Manage Email Alerts
Glaucomatous loss can be diagnosed with time-domain optical coherence tomography when the rate of age-related changes in the peripapillary retinal nerve fiber layer occur more quickly than expected in a certain area, a study said.
Researchers conducted standard and fast peripapillary RNFL scans on 425 normal subjects ranging in age from 18 to 85 years. Stratus time-domain OCT (Carl Zeiss Meditec) with nominal diameter of 3.46-mm centered on the optic disc.
The mean average RNFL thickness was 104.7 ± 10.8 µm, with a decrease of 2.4 µm per decade of age.
The changes in RNFL thickness per decade of age ranged from -5.4 (P < .001) at clock hour 1 to -0.9 (P = .28) at clock hour 6, the study said.
Researchers found that the rate of RNFL thickness change per decade of age in the superior quadrant was -4.3 (P < .001) compared with -1.5 (P = .006) in the inferior quadrant. In addition, the slopes of thinning were highly significantly different between quadrants (P = .001), according to the study.
"To conclude glaucomatous loss has occurred, the average thickness should decline more rapidly than the fastest rate of age-related decline of the average thickness at the 95% tolerance limit," the authors said.