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. 2021 Feb 25;12(3):330. doi: 10.3390/genes12030330

Figure 1.

Figure 1

Optical coherence tomography (OCT) segmentation, electroretinogram (ERG) and disc photo grading. (A) Schematic diagram showing how average thickness for the sum of the ganglion cell and inner plexiform layers (GCL-IPL) was segmented from a 6 mm by 6 mm OCT macular cube scan for an elliptical annulus centered on the fovea with inner axis radius of 0.5 mm and outer axis radius of 2.0 mm, stretched by 20% in the horizontal direction. (B) Macular OCT segmentation: The blue line indicates the boundary between the GCL and retinal nerve fiber layer; the yellow line shows the boundary between the IPL and inner nuclear layer (case 16). (C,D) Peripapillary OCT segmentation: retinal nerve fiber layer (RNFL) thickness was determined using the Cirrus inbuilt analysis tool; (C) RNFL thickness map and (D) RNFL thickness graph (case 14; average RNFL thickness 61 µm; temporal RNFL thickness 44 µm). (E) Control ERG: The electroretinogram a-wave was measured from the prestimulus baseline to the trough, and the b-wave amplitude from the a-wave trough to the subsequent peak. (F) Electronegative ERG (case 9): the b-wave amplitude is smaller than the a-wave amplitude (b/a ratio < 1). (G–J) Color fundus photos were graded by a pediatric neuro-ophthalmologist as exhibiting (G) no disc pallor (case 10); (H) two clock hours of disc pallor (case 12); (I) three clock hours disc pallor (case 22) and (J) five clock hours of optic disc pallor (case 16).