OCT for the Detection of New-Onset CNV
The authors of this prospective, multicenter, observational study sought to determine the sensitivity of time domain optical coherence tomography (OCT) in detecting conversion to neovascular age-related macular degeneration (AMD) in eyes at high risk for choroidal neovascularization (CNV), compared with detection using fluorescein angiography (FA) as the gold standard.
They included individuals aged ≥ 50 years with non-neovascular AMD at high risk of progressing to CNV in the study eye and evidence of neovascular AMD in the fellow eye. The study authors noted that at study entry and every 3 months through 2 years, participants underwent best-corrected visual acuity, supervised Amsler grid testing, preferential hyperacuity perimetry (PHP) testing, stereoscopic digital fundus photographs with FA, and OCT imaging. A central Reading Center graded all images. Main outcome measures included the sensitivity of OCT in detecting conversion to neovascular AMD by 2 years, using FA as the reference standard. Secondary outcomes included comparison of sensitivity, specificity, positive predictive value, and negative predictive value of OCT, PHP, and supervised Amsler grid relative to FA for detecting incident CNV.
The authors enrolled 98 participants; 87 (89%) of these individuals either completed the 24-month visit or exited the study after developing CNV. They noted that 15 (17%) study eyes had incident CNV confirmed on FA by the Reading Center. The sensitivity of each modality for detecting CNV was: OCT 0.40 (95% confidence interval [CI], 0.16–0.68), supervised Amsler grid 0.42 (95% CI, 0.15–0.72), and PHP 0.50 (95% CI, 0.23–0.77). The authors recommended treatment for incident CNV in 13 study eyes. Sensitivity of the testing modalities for detection of CNV in these 13 eyes was 0.69 (95% CI, 0.39–0.91) for OCT, 0.50 (95% CI, 0.19–0.81) for supervised Amsler grid, and 0.70 (95% CI, 0.35–0.93) for PHP. Specificity of the OCT was higher than that of the Amsler grid and PHP.
Time-domain OCT, supervised Amsler grid, and PHP have low to moderate sensitivity for detection of new-onset CNV compared with FA, the authors concluded. They also found that OCT has greater specificity than Amsler grid or PHP. Among fellow eyes of individuals with unilateral CNV, FA remains the best method to detect new-onset CNV.