CORRELATION OF CENTRAL CORNEAL THICKNESS ON OCT AND PACHYMETRY IN GLAUCOMA PATIENTS

*Dr. Priyanka Kolhe, Dr. Chandni Karole, 3Dr. Shivam Goyal and Dr. Deepti Mujumdar

ABSTRACT

BACKGROUND AND AIM: Central corneal thickness (CCT) measurement has become an important test in the diagnosis and management of glaucoma. Currently, ultrasound corneal thickness measurement (pachymetry) is the most frequently used clinical technique and the gold standard to assess CCT. Newer instruments are currently available including the optical coherence tomography (OCT) instrument. The aim of the present study was therefore to evaluate the accuracy of the CCT measurements, both with the OCT and ultrasound pachymetry (USP), in patients suffering from glaucoma. METHODS: Cross-sectional study, Ophthalmological examination was performed before including patients in the study. Visual acuity by snellens chart, IOP measurements by goldmann applation tonometer , optic nerve status by 90D lens slit lamp biomicroscopy, gonioscopy, Humphrey visual fields (HFA, 24–2), and presence or absence of exfoliation were noted after pupil dilatation under slit lamp examination. Glaucoma was defined as patients who had at least two repeatable Humphrey visual fields showing glaucoma damage using the software 24–2, and with the optic nerve showing typical glaucoma damage. RESULTS: 48 eyes of 25 patients were included. The average age was 64 ± standard deviation (SD) 10.88, the average pachymetry value with OCT was 536 ± 29 μm, and the average pachymetry with USP was 532 ± 32μm. The differences between OCT and USP were not significant (t-test, p = 0.32). The intraclass correlation coefficients were, for OCT, 0.99 [confidence interval (CI): 0.98–0.996], and for USP, 0.97 (CI: 0.95–0.98). CONCLUSIONS: OCT and USP both showed high accuracy in pachymetry measurements. OCT Might be used as a substitute for pachymetry, if USP is not available.

Keywords: Optical coherence tomography, USP pachymetry, humphery perimetry, central corneal thickness, glaucoma.