Abstract
Purpose :
Previous studies have shown reduction of OCT-measured retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL) and increased inner nuclear layer (INL) along with microcystic abnormalities in the macular area. However, it is still unclear what is the mechanism of INL abnormalities and whether outer retinal layers are also involved in such cases. The purpose of the study is to compare all 7 segmented retinal layers in eyes with band atrophy (BA) and controls. We also assessed possible correlation between OCT and 10-2 standard automated perimetry (SAP).
Methods :
Fifty-one eyes (32 patients) with temporal hemianopia (and normal nasal VF) and BA of the optic nerve and 41 eyes of 21 controls underwent SD-OCT (Heidelberg Spectralis) imaging to obtain posterior pole quadrant analysis. After segmentation, we obtained measurements from RNFL, GCL, inner plexiform layer (IPL), INL, outer plexiform layer (OPL), outer nuclear layer (ONL) and photoreceptor layer (PRL). Average thickness of superior nasal (SNQ), inferior nasal (INQ), superior temporal (STQ) and inferior temporal (ITQ) quadrants were compared between normal and BA patients.
Results :
Table 1 show results of thickness measurements in 4 quadrants and different layers of BA eyes and controls. RNFL, GCL and IPL were significantly reduced in all 4 quadrants compared to controls. INL, OPL and PRL were significantly increased in the nasal quadrants and did not differ in the temporal ones. No significant difference was observed in the ONL in any quadrant. Significant correlations between OCT measurements and 10-2 SAP were positive for RNFL, GCL and IPL and negative for INL, OPL and PRL, especially in the nasal quadrants, as shown in Table 2.
Conclusions :
Band atrophy leads not only to RNFL, RGCL and IPL thinning, but also INL, OPL and PRL thickening. Different layers thicknesses measured in OCT segmentation correlates with SAP sensitivity. Abnormalities in the outer retinal layers indicate a possible secondary retinal disturbance. Although further studies are necessary to clarify this issue, awareness of such occurrence is very important both in management and understanding of disease.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.