INTRA OCULAR PRESSURE

CORRELATION BETWEEN CENTRAL CORNEAL THICKNESS AND INTRA OCULAR PRESSURE

Abstract

Introduction: The ideal optical properties of the eye requires support of state of the eye-ball which is normally regulated by the intraocular pressure (IOP). There is variation in the measurements of IOP with Goldmann applanation tonometry if the thickness of the central cornea is not uniform, the IOP is high when cornea is thicker and vice versa. Therefore, the central corneal thickness (CCT) is thought to affect the IOP readings, however, as shown, the evidence available remains controversial. The aim of the study was to determine correlation between CCT and IOP. Objectives: To determine the correlation between the Central Corneal Thickness (CCT) and Intra Ocular Pressure (IOP). Study Design: A cross-sectional study. Place
and Duration: Department of Ophthalmology, Aga Khan University Hospital, Karachi from July to December, 2014. Methodology: During the study period of six months total 431 participants were purposively sampled according to the set criteria. Variables included were age, gender, CCT, and IOP. Correlation between IOP and CCT was assessed by using Pearson correlation test, P value of < 0.05 was considered significant. Results: Out of 431 participants, 239 (55.5%) males and 192 (44.5%) females. The mean age was 34.9 ranging from 20 to 50 years. The mean central corneal thickness of right eye was 529 μm with SD ± 39.5 and range of 473-591 μm. The mean intraocular pressure of right eye was 14.7 μm, SD ± 3.1 with a range of 9-21 mmHg. The left eye mean central corneal thickness was 533, SD ± 29.6 with range of 481-589 μm. The mean intraocular pressure of left eye was 15.6, SD ± 3.1 with a range of 10-21 mmHg. Strong positive correlation was found (P-value < 0.001) between central corneal thickness and
intra ocular pressure for both eyes. Conclusion: There is positive correlation between CCT and IOP. Therefore, along with the routine ophthalmic examination for intraocular pressure measurements pachymetry should also be considered for accurate interpretation of the results.