Abstract
Purpose: :
To compare the performance of the slit-lamp anterior segment optical coherence tomography (SL-OCT) and scanning peripheral anterior chamber depth analyzer (SPAC) in the evaluation of angle closure in Asian eyes, using gonioscopy as the reference standard.
Methods: :
153 phakic subjects underwent gonioscopy, SL-OCT and SPAC in this hospital-based prospective comparative study. Gonioscopy was performed by a single ophthalmologist masked to other test results, and the angle was graded using the Scheie grading system. An eye was considered closed on gonioscopy if the posterior trabecular meshwork was not visualized in at least one quadrant. Angle closure was defined on SL-OCT by the presence of peripheral iris contact with the angle wall anterior to the scleral spur, and with SPAC by a numerical grade of <5 and categorical grade of "s" (suspect) or "p" (potential).
Results: :
Angle closure was observed in 51, 86 and 61 eyes with gonioscopy, SL-OCT and SPAC respectively (gonioscopy vs SL-OCT, p<0.001; gonioscopy vs SPAC, p=0.10; SL-OCT vs SPAC, p<0.001 [McNemar Test]). SL-OCT identified 43 of 51 eyes while SPAC identified 41 of 51 eyes diagnosed to have angle closure on gonioscopy (p=0.79, McNemar Test). An open angle in all 4 quadrants was found in 102 eyes on gonioscopy. Of these, 43 and 20 eyes were identified as closed by SL-OCT and SPAC respectively. The overall specificity of SL-OCT was 61% and SPAC 82%, while the sensitivity of both SL-OCT and SPAC were 84% and 80% respectively.
Conclusions: :
Using gonioscopy as the reference standard, both SL-OCT and SPAC were highly sensitive in detecting angle closure. Compared to SPAC, the SL-OCT tends to over-estimate the number of eyes with angle closure.
Keywords: imaging/image analysis: clinical • anterior chamber