Peripapillary retinal nerve fiber layer and perifoveal macula thickness: Which one is more helpful in the early diagnosis of primary open angle glaucoma using optical coherence tomography angiography?

Abstract

Background: Macula involvement in early glaucoma changes of the retina is still inconclusive. The objective of the study was to compare the precision of parameters of peripapillary retinal nerve fiber layer (pRNFL) thickness  and the macula in the diagnosis of early primary open angle glaucoma (POAG).

Purpose: To evaluate the pRNFL and perifoveal inner macula thicknesses in the early diagnosis of POAG using optical coherence tomography  angiography (Angio-OCT).

Materials and Methods: Fifty-five subjects were included in a prospective, crosssectional study divided into three groups: early glaucoma (EG) group (46 eyes of 25 patients with early POAG), glaucoma suspects (GS) group (34 eyes of 20 subjects), and control group (20 eyes of 10 healthy subjects). The mean age of the respective groups was 65.47 ± 9.59, 56.53 ± 9.31, and 51.65 ± 4.16. All subjects underwent Angio-OCT scanning using RTVue-100  }Оptovue.} The optic nerve head scan was used for the pRNFL and Retina Thickness Map 5 × 5mm scan for perifoveal inner macula region.  Parameters analyzed were total average, superior, inferior, temporal, and nasal thicknesses of both regions.

Results: There was thinning in both pRNFL and perifoveal inner macula thicknesses in the EG group compared to the N group. Mann–Whitney intergroup analysis revealed statistically significant differences between the EG and the N groups in all parameters of the perifoveal inner macula thickness, while for the pRNFL thicknesses, there were differences only in total average, superior, and inferior thicknesses. The temporal and nasal perifoveal inner macula thicknesses were parameters with highest areas under the receiver operating characteristic curve (0.907 and 0.900, respectively).

Conclusion: In early detection of glaucomatous optic neuropathy in POAG, parameters of perifoveal inner macula thickness are diagnostically more significant compared to pRNFL thickness using the Angio-OCT.

Keywords: Angio-OCT, early diagnosis, primary open angle glaucoma