Abstract
Purpose :
To evaluate test retest reliability of hand-held spectral domain optical coherence tomography (HH-SDOCT) for measurements of iridocorneal angle in normal children and children with glaucoma
Methods :
A cross-sectional study involved scanning the eyes of 65 normal children (mean age= 5.12 ± 3.5 years, range: 2 days to 12 years) and 18 children with glaucoma (mean age =3.48 ± 3.9, range: 1 month to 13 years) using HH-SDOCT (Leica Microsystems Ltd). Two repeated scans were obtained per eye on the same examination day. Each scan was captured within 0.96 seconds and contained 11 B-scans with 3000 A-scans per B-scan. Images showing both clear nasal and temporal angles were imported into ImageJ and single B-scans were analysed. The iridocorneal angle landmarks: scleral spur (SS), Schwalbe`s line (SL) and angle recess (AR) were identified and used to calculate trabecular meshwork length (TML), scleral spur angle opening distance (SSAOD), Schwalbe`s line angle opening distance (SLAOD), trabecular iris surface area (TISA) and TISA500 (see figure). Repeatability and reproducibility of measurements were assessed using interclass correlation coefficient (ICC) and Bland-Altman plots.
Results :
SLAOD, SLTISA and TISA500 were highly reproducible in both normal children and children with glaucoma with ICC of 0.92, 0.83 and 0.91 in controls and 0.91, 0.83 and 0.90 in glaucoma patients, respectively. The relative mean difference of repeated measures for TML, SSAOD, SLAOD, TISA and TISA500 were 0.7, 2.6, 3.2, 2.9 and 5.8% in normal, and 0.8, 0.2, 2.5, 2.6 and 5.5% in glaucoma, respectively. Average TML, SSAOD, SLAOD, TISA and TISA500 was 713.9 ± 98.7µm, 208.1 ± 71.3µm, 646.4 ± 155.3µm, 0.33 ± 0.1mm2 and 0.25 ± 0.1mm2 in normal children, and 741.7 ± 174.4µm, 197.7 ± 131.0µm, 846.8 ± 284.1µm, 0.44 ± 0.2mm2 and 0.33 ± 0.1mm2 in glaucoma, respectively. SLAOD and TISA500 were significantly higher in glaucoma patients compared to controls (mean difference: 200.4 ± 63.3µm (P=0.005) and 0.08 ± 0.07mm2 (P=0.02), respectively).
Conclusions :
HH-SDOCT is a reliable technique for measuring iridocorneal angle in children with excellent reproducibility for SLAOD. Children with glaucoma had wider SLAOD compared to normal children. Anterior segment OCT could be a useful addition to glaucoma management in children.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.