Ganglion Cell Complex thickness as an early predictor of microstructural changes in varying degrees of myopia in comparison with Retinal Nerve Fiber Layer (RNFL) thickness

Purpose : To compare the Ganglion Cell Complex (GCC) thickness with Retinal Nerve Fiber Layer
(RNFL) thickness in correlation with visual field (VF) in varying degrees of myopia. Design: a Cross-
Sectional study. Participants: Ninety-six eyes of 49 patients with myopia. Methods: Patients with
myopia examined with streak retinoscope to obtained the best corrected visual acuity based on
spherical equivalent. Patients then divided into low (50 eyes=50.1%), moderate (31 eyes=32.3%), and
high (15=15.6%) myopia. Axial length measured with A-Scan ultrasound divided into short (4=4.2%),
moderate (74=77.1%), and long (18=18.7%). SD-OCT was used to measured GCC thickness in 9 areas
including fovea (R1), parafovea (R2-R5), and perifovea (R6-R9) according to early treatment diabetic
retinopathy study (ETDRS), and RNFL thickness in five areas (G, TS, TI, NS, N, NI). VF analysis
with humphrey field analyzer with SITA 24-2 pattern. Main outcome measures: GCC thickness has
higher correlation with degree of myopia particularly in perifovea area and means deviation than
RNFL thickness. Results: GCC thickness decreased significantly along with the elevation of myopia
degree in almost entire area except R1 and R5 . Parafovea (R2-R4) and perifovea (R6-R9) were
significantly correlated with p= 0.001, 0.005, 0.006 and p= 0.000, 0.000, 0.000, and 0.003
respectively. In contrast, RNFL thickness obtained lower correlation with myopia degree whereas the
only significant result was found in Nasal area (p= 0.045). VF found to be strongly correlated with the
degree of myopia in which p-value for Mean Deviation = 0.000. Conclusions: GCC thickness may
compare the predictive value of RNFL in predicting early retinal microstructural changes even in low
degree myopia. Financial Disclosure: Author has no financial disclosure.