Aim: To assess the CCT and its relationship with cup disc ratio and RNFL thickness in POAG and PACG patients. Design: Prospective observational study. Material and Method: This study was carried out at the Regional Institute of M.L.N. Medical College and Hospital Prayagraj from December 2018 to November 2019. A total of 43 eyes, 17(29 eyes) patients of POAG , 8 (14 eyes) patients of PACG included. Measurement of CCT done by Specular Microscope and (RNFL) thickness evaluated by OCT. Results: In thinner cornea group (450–500 μm) CCT is more positively correlated with RNFL thickness in both PACG (r = 0.420) and PAOG (r = 0.451) patients. CCT and CD ratio was more negatively correlated in PACG patient (r = –0.652) for vertical and (r = –0.907) for horizontal CD ratio than in PAOG patients (vertical CD ratio r = –0.018 and horizontal r = –0.022). In thicker cornea group i.e.
501–550 μm average RNFL thickness was more positively correlated with the CCT variation in POAG (r = 0.448) than in PACG (r = 0.219 ). CCT was more negative correlated with cup disc ratio in PAOG group (r = –0.447) than in PACG group (r = –0.104 ) of patients. Conclusion: In thinner cornea group (450–500 μm) there is a definite positive correlation between CCT and RNFL thickness. Both average and quadrantric RNFL thickness was more pronounced in PACG Group as compared to POAG group. However in thicker Cornea (501–550μm) group CCT is more positively correlated with RNFL loss in POAG as compared to PACG group. Also POAG group exhibited more rapid increase in cup disc ratio with thinning of cornea.

Keywords: (CCT) Central corneal thickness; (RNFL) Retinal nerve fiber layer; (POAG) Primary open angle glaucoma; (PACG) Primary angle closer glaucoma.