Evaluation of scanning protocols for imaging the anterior chamber angle with anterior segment-optical coherence tomography.
OBJECTIVE
To evaluate different anterior segment-optical coherence tomography (AS-OCT) scanning protocols for detecting eyes with angle closure.


METHODS
This cross-sectional study enrolled 2104 subjects from a community clinic in Singapore. All participants underwent AS-OCT imaging in the dark (Visante, Carl-Zeiss, Meditec, Dublin, CA), and gonioscopy with a Goldmann 2-mirror and a Sussman lens by an experienced examiner. The anterior chamber angle in a particular quadrant was considered closed on gonioscopy if the posterior trabecular meshwork could not be seen; and on AS-OCT by the presence of contact between the iris and angle wall anterior to the scleral spur. Protocols using combinations of AS-OCT scans of different quadrants of the eye were compared.


RESULTS
A total of 1853/2104 right eyes could be graded in all 4 quadrants. In all, 380 (20.5%) eyes had closed angles in at least 2 quadrants on gonioscopy. The AS-OCT scanning protocol that only imaged the inferior quadrant showed the best area under the receiving operating characteristic curve (AUC 0.76, sensitivity 84%, specificity 69%) for detecting angle closure. Although technically easier to obtain, the protocol that only included the nasal-temporal quadrants had the lowest AUC (AUC 0.67, sensitivity 47%, specificity 88%), whereas scanning the superior-inferior quadrants showed high sensitivity for detecting angle closure (92%), but low specificity (54%).


CONCLUSIONS
Using the results obtained in a research setting, the diagnostic performance of AS-OCT varied according to the adopted scanning protocol. The inferior quadrant-only protocol showed the best diagnostic performance but the low specificity would limit its use for population screening.
Singapore Eye Research Institute & Singapore National Eye Center.
Wei-Boon
WB
Khor
Lisandro M
LM
Sakata
David S
DS
Friedman
Arun
A
Narayanaswamy
Raghavan
R
Lavanya
Shamira A
SA
Perera
Tin
T
Aung
D000368:Aged; D000369:Aged, 80 and over; D000869:Anterior Eye Segment / Q000473:pathology*; D005260:Female; D015812:Glaucoma, Angle-Closure / Q000175:diagnosis*; D006068:Gonioscopy; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D041623:Tomography, Optical Coherence; D014065:Tonometry, Ocular