Effect of Ocular Magnification Correction on Measurements of Macula Ganglion Cell Complex in Myopic Children.

PURPOSE: Optical Coherence Tomography (OCT) imaging in myopic eyes may be influenced by measurement error from axial length-induced magnification effects. We studied the effects of magnification correction on ganglion cell complex (GCL++) thickness in myopic children.

DESIGN

Clinical cohort.

SUBJECTS: Children aged 7 to 16 years in a myopic clinic.

METHODS

Data collected included age, gender, race, cycloplegic refraction, axial length (AL), keratometry (K), intraocular pressure (IOP), cup-to-disc ratio (CDR), optic disc tilt, peripapillary atrophy (PPA) and OCT macula scans from the right eye. GCL++ thickness in the central, inner and outer superior, inferior, nasal and temporal quadrants was measured with or without adjustments for ocular magnification using the Littmann-Bennett formula.

RESULTS

492 subjects, comprising 46.7% male and 91.8% Chinese with an average age of 10.3 ± 1.6 years were included in the study. Mean spherical equivalent (SE) was -4.43 ± 2.24D, and AL was 25.04 ± 1.05 mm. Multivariate analysis showed unadjusted and adjusted GCL++ thickening in older age; in the central and inner quadrants in males; and in the outer temporal quadrant in Chinese children. Central unadjusted and adjusted GCL++ were also thicker with decreased SE, flatter K and increased AL. In other quadrants, unadjusted GCL++ was thinner with decreasing SE and increasing AL in all but the nasal quadrant. Adjusted values were thicker with decreased SE, flatter K, and increasing AL (P ≤ .001 for all). IOP, CDR, optic disc tilt, PPA and myopia treatment had no effect on GCL++.

DISCUSSION: Ocular magnification correction of OCT-measured retinal layer thickness using adjustments for axial length suggests increasing myopia is associated with thickening of the ganglion cell complex in children.