Purpose
To investigate the topographic correlation between ganglion cell-inner plexiform layer (GCIPL) and circumpapillary retinal nerve fiber layer (cpRNFL) defect in patients with localized RNFL defects using spectral domain (Cirrus) optical coherence tomography (OCT)
Methods
Fifty-four eyes of 54 patients showing localized RNFL defects on red-free RNFL photographs (angular width less than 30 degrees) were included. The angular location of the defect (angle α) and the angular width of the defects were measured from the RNFL photograph. The cpRNFL and GCIPL thickness measurements and deviation map analysis from normative database were performed by OCT (Figure 1). Topographic associations between angle α, clock-wise positions of cpRNFL defect, and GCIPL defect were evaluated.
Results
Topographic associations between clock-wise positions of cpRNFL defect and 6 sectors of GCIPL were: localized RNFL defect at 7 o/c → defect at all inferior sectors; 8 o/c → inferior and inferotemporal sectors; 10, 11 o/c → all superior sectors (Figure 2). Six sectors showed different distribution of angle α; however, there was overlap in range of angle α between adjacent sectors. Minimum angle α in eyes showing defects in inferonasal, inferior, inferotemporal, superotemporal, superior, and superonasal sectors were 296.3, 284.3, 272.7, 48.7, 45.3, and 43.1degrees, respectively. Maximum angle α in eyes showing defects were 340.3, 323.6, 312.8, 96.3, 76.4, and 58.2 degrees, respectively. The average angle α in eyes showing defects were 320.6, 308.0, 296.3, 68.2, 56.8, and 49.9 degrees, respectively.
Conclusions
Topographic correlation between cpRNFL and GCIPL defect can be obtained from patients with localized RNFL defects using angle α on red-free RNFL photographs and cpRNFL and GCIPL thickness deviation maps. The results reflect the topographic location of retinal ganglion cell death associated with the clock hour location of cpRNFL loss in vivo.
Keywords: 531 ganglion cells •
610 nerve fiber layer •
552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)