Retinal tomographic measurements in optic disc pit

Abstract

Background: The aim was to assess the Heidelberg Retina Tomograph II measurements in optic disc pit.Methods: The study included 10 patients with a unilateral optic disc pit. The patients had no other ocular conditions except refractive errors. Normal fellow eyes of the patients were used as a control group. Optic nerve head topographic analyses were performed using a confocal scanning laser ophthalmoscope, Heidelberg Retina Tomograph II (HRT II).Results: The topographic parameters of the eyes with optic disc pit and normal fellow eyes were as follows, respectively: disc area (3.77 ± 1.50 and 3.07 ± 0.83-mm2), cup area (1.99 ± 1.71 and 1.09 ± 0.54-mm2), rim area (1.67 ± 0.55 and 1.87 ± 0.75-mm2), cup volume (0.94 ± 1.24 and 0.34 ± 0.27-mm3), rim volume (0.51 ± 0.40 and 0.55 ± 0.19-mm3), mean cup depth (0.44 ± 0.20 and 0.31 ± 0.11-mm) and mean retinal nerve fibre layer thickness (0.25 ± 0.20 and 0.28 ± 0.59-mm). Eyes with an optic disc pit were found to have significantly larger disc area compared to fellow eyes (p = 0.038). All the other parameters showed no statistically significant interocular differences (p > 0.05).Conclusion: Our study demonstrates that the optic disc pit affects only the disc area measurement in HRT II. Other changes in optic nerve head morphometric parameters were insignificant. The clinician must be careful in the evaluation of HRT II results with respect to optic disc area in a disc with a pit.