Macular ganglion cell‐Inner plexiform layer thickness measurement and reproducibility with SD‐OCT

Abstract

AbstractPurpose To evaluate the macular retinal ganglion cell‐inner plexiform layer (GC‐IPL) thickness with automated detection and analyze the intra and interobservator reproducibility in normal, ocular hypertensive (OHT) and glaucomatous eyes.Methods A total of 138 eyes were enrolled in 3 goups: normal subjects (n=69), OHT subjects (n=35), and open angle glaucoma subjects (n=34). All patients underwent a complete ocular examination including 24‐2 standard automated perimetry, biometry and pachymetry. Each eye had macular scanning using the Cirrus HD‐OCT (Carl Zeiss Meditec, Dublin, CA, USA), 3 times by each of 2 observators, and the ganglion cell analysis (GCA) algorithm provided parameters as average, minimum and 6 sectoral GC‐IPL thicknesses. The reproducibility was assessed with intraclass correlation coefficient (ICC), coefficient of variation (CV) and test‐retest SD (TRTSD).Results The mean GC‐IPL thickness was 82.27 ± 7.37 µm, 76.84 ± 7.01 µm and 66.16 ± 11.16 µm in normal, OHT, and glaucoma group respectively. The GC‐IPL thickness was significantly lower in glaucomatous eyes than in normal and OHT eyes (p<0.0001 for all parameters). In the 3 groups ICC ranges were 96.4‐99.9 % and 92.5‐99.8 %, CV ranges were 0.41‐2.24 % and 0.55‐1.67 %, and TRTSD ranges were 0.61‐2.64 µm and 0.83 and 2.22 µm, for respectively the intraobservator and interobservator reproducibility analysis.Conclusion To our knowledge this is the first study of GCA algorithm in normal, OHT and glaucomatous eyes. A highly satisfactory reproducibility of GC‐IPL thickness measurements using Cirrus HD‐OCT is reported. GC‐IPL thickness might be promising new OCT parameter for glaucoma diagnosis and follow‐up.