Purpose
To follow the changes in circumpapillary, retinal nerve fiber layer (RNFL) thickness seen with frequency domain optical coherence tomography (fdOCT) after an optic disc hemorrhage (DH) has been visualized on a fundus photograph.
Methods
In this prospective study, after a DH was confirmed by stereophotography, fdOCT disc cube scans (6x6 mm; 3D-OCT2000, Topcon) and 24-2 visual fields (Zeiss) were obtained from 18 eyes of 17 glaucoma patients (age: 66.2±10.6 years). The last fdOCT scan was obtained on average 39.8±16.6 mos. (range 17.1 to 68.6 mos.) after the first. For each eye, en-face images of the first and last scans were registered by rotating to align the blood vessels. After alignment, circumpapillary circle images were derived for an annulus 100 µm in width and RNFL thickness profiles (Fig. 1, lower) were plotted for the first (dashed) and last (solid) visits. The width of the defects (red and blue horizontal lines in Fig. 1, upper) associated with the DH was measured as the region falling below the 1% confidence interval (red region in Fig. 1, lower) of OCT machine’s norms.[1]
Results
There were 19 DHs; 16 were located in the inferior half of the disc (temporal and inferior quadrants), while 3 were in the superior quadrant (Fig. 1, upper). The width of the local RNFL thinning increased on average by 9.6±7.7° (range 0 to 26.4°) between the first (average: 24.1±13.8°) and last (average: 34.5±17.7°) scans (p<0.00031). While 18 of the 19 regions associated with a DH showed an increase in width (Fig. 1, upper), only 11 of the 18 eyes showed a decrease in the 24-2 mean deviation (MD). The MD decreased on average by -1.97±2.79 dB (range 0.11 to -9.6 dB) between the first (-4.0± 4.18 dB) and last (-5.98±5.31 dB) visit (p<0.008).
Conclusions
The change (thinning) of the circumpapillary RNFL after optic disk hemorrhages can be followed with fdOCT if successive scans are appropriately aligned. This is particularly important in the case of DHs in the inferior disc as they involve damage to the macula.[2] 1. Hood, Raza (2014) BJO; 2. Hood et al. (2013) PRER.