https://doi.org/10.1177/1120672118806436
European Journal of Ophthalmology
1–7
© The Author(s) 2018
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DOI: 10.1177/1120672118806436
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Ophthalmology
Introduction
Gonioscopy is an essential part of the ophthalmic exami-
nation.
1–4
In clinical practice, it is mostly used to differen-
tiate between open and angle closure, as both management
and severity may differ substantially. This technique can
provide useful information such as pigmentation of the tra-
becular meshwork (TM), the presence of Sampaolesi line,
synechiae, iris processes, blood in Schlemm’s canal,
abnormal blood vessels in the angle and angle recession,
among other angle structural abnormalities.
1–4
Unfortunately, manual techniques have a number of
caveats, ranging from a longer-than-desired learning
curve, to being uncomfortable for the patient. Moreover,
while they can provide a 360° angle evaluation, it may
only provide a brief (almost fleeting) image of the iridoc-
orneal angle (ICA).
3–6
Specifically to the non-glaucoma
specialists, due to lack of training in performing gonios-
copy, this may pose significant challenges.
5–8
Other objective ways to examine the ICA, and for angle
grading, include ultrasound biomicroscopy (UBM), ante-
rior segment optical coherence tomography (AS-OCT)
and Scheimpflug photography.
5,7
All of these exams do
not provide sufficient structural details of the ICA. UBM
is essential to evaluate posterior structures to the angle,
ciliary body and iris posterior face, but it requires a
skilled operator and long image acquisition times.
2,9
Automated gonioscopy photography
for iridocorneal angle grading
Filipa Teixeira
1,2
, David C Sousa
1,2,3
, Inês Leal
1,2,3
,
André Barata
1,2
, Carlos M Neves
1,2,3
and Luís A Pinto
1,2,3
Abstract
Purpose: The aim of this study is to assess the agreement between manual and automated gonioscopy for iridocorneal
angle opening.
Methods: The research is a cross-sectional observational study. Manual and automated gonioscopy were performed
to consecutive patients in a glaucoma clinic. Iridocorneal angle opening grading was performed according to Shaffer’s
classification. Automated gonioscopy was performed with NGS-1 automated gonioscope (NIDEK Co., Gamagori, Japan).
The automated gonio-photos were graded by two independent observers. Agreement between automated and manual
gonioscopy and also among raters was ascertained by Fleiss’ kappa statistic and comparison of area under curve.
Results: In total, 88 eyes of 47 subjects were analysed. Mean age was 63 ± 10 years. Twenty eyes (22.7%) were excluded
from grading due to poor quality images. Angle closure was detected in 23.4% with dynamic gonioscopy in comparison
with 4.3% using automated image grading. The agreement for angle closure diagnosis between dynamic and automated
gonioscopy was low (κ = 0.09 ± 0.10; p = 0.18). The area under curve for detecting eyes with angle closure showed poor
accuracy between automated and manual methods (area under curve: 0.53 ± 0.05, 95% confidence interval: 0.44–0.62).
There was modest inter-rater agreement for angle opening assessment of automated images with Fleiss’ kappa of 0.17
(95% confidence interval: 0.035–0.238).
Conclusion: Manual and automated gonioscopy showed only slight agreement for the assessment of iridocorneal angle
opening status. Further improvements of the NGS-1 automated gonioscopy and technique are desired for widespread
use in a real-life setting.
Keywords
Anterior chamber angle, iridocorneal angle, gonioscopy, automated grading
Date received: 10 April 2018; accepted: 19 September 2018
1
Department of Ophthalmology, Hospital de Santa Maria, Lisbon,
Portugal
2
Clínica Universitária de Oftalmologia, Faculdade de Medicina,
Universidade de Lisboa, Lisbon, Portugal
3
Centro de Estudos Ciências da Visão, Faculdade de Medicina,
Universidade de Lisboa, Lisbon, Portugal
Corresponding author:
Luís A Pinto, Department of Ophthalmology, Hospital de Santa Maria,
Avenida Professor Egas Moniz, 1649-035 Lisbon, Portugal.
Email: abegaopinto@gmail.com
806436EJO 0 0 10.1177/1120672118806436European Journal of OphthalmologyTeixeira et al.
research-article 2018
Original Research Article