Agreement of angle closure assessments between gonioscopy, anterior segment optical coherence tomography and spectral domain optical coherence tomography.
OBJECTIVE
To determine angle closure agreements between gonioscopy and anterior segment optical coherence tomography (AS-OCT), as well as gonioscopy and spectral domain OCT (SD-OCT). A secondary objective was to quantify inter-observer agreements of AS-OCT and SD-OCT assessments.


METHODS
Seventeen consecutive subjects (33 eyes) were recruited from the study hospital's Glaucoma clinic. Gonioscopy was performed by a glaucomatologist masked to OCT results. OCT images were read independently by 2 other glaucomatologists masked to gonioscopy findings as well as each other's analyses of OCT images.


RESULTS
Totally 84.8% and 45.5% of scleral spurs were visualized in AS-OCT and SD-OCT images respectively (P<0.01). The agreement for angle closure between AS-OCT and gonioscopy was fair at k=0.31 (95% confidence interval, CI: 0.03-0.59) and k=0.35 (95% CI: 0.07-0.63) for reader 1 and 2 respectively. The agreement for angle closure between SD-OCT and gonioscopy was fair at k=0.21 (95% CI: 0.07-0.49) and slight at k=0.17 (95% CI: 0.08-0.42) for reader 1 and 2 respectively. The inter-reader agreement for angle closure in AS-OCT images was moderate at 0.51 (95% CI: 0.13-0.88). The inter-reader agreement for angle closure in SD-OCT images was slight at 0.18 (95% CI: 0.08-0.45).


CONCLUSIONS
Significant proportion of scleral spurs were not visualised with SD-OCT imaging resulting in weaker inter-reader agreements. Identifying other angle landmarks in SD-OCT images will allow more consistent angle closure assessments. Gonioscopy and OCT imaging do not always agree in angle closure assessments but have their own advantages, and should be used together and not exclusively.
Department of Ophthalmology, Tan Tock Seng Hospital, Singapore 308433, Singapore ; Republic of Singapore Air Force Aeromedical Centre, Singapore 539945, Singapore.
Elton Lik Tong
EL
Tay
Department of Ophthalmology, Tan Tock Seng Hospital, Singapore 308433, Singapore.
Vernon Khet Yau
VK
Yong
Department of Ophthalmology, Tan Tock Seng Hospital, Singapore 308433, Singapore.
Boon Ang
BA
Lim
Cardinal Santos Medical Center, San Juan City, Metro Manila 1502, Philippines.
Stelson
S
Sia
Department of Ophthalmology, Tan Tock Seng Hospital, Singapore 308433, Singapore.
Elizabeth Poh Ying
EP
Wong
Department of Ophthalmology, Tan Tock Seng Hospital, Singapore 308433, Singapore.
Leonard Wei Leon
LW
Yip
angle closure assessment; anterior segment imaging; spectral domain imaging