Purpose
To determine the relationship between Central Corneal Thickness (CCT) and Intraocular pressure (IOP) in indigenous Africans in Nigeria
Methods
A population - based cross - sectional study was carried out on indigenous Africans in a selected population in Lagos State, Nigeria. After obtaining written informed consent, all participants underwent detailed evaluation including medical and ocular history and examination. The central corneal thickness was determined with AccuPach VI Ultrasound Pachymeter and IOP by the Perkins handheld applanation tonometer. All measurements of IOP and CCT were taken between 10.00am and 1pm to control for diurnal variation.The measurement of both the CCT and IOP were carried out by a single examiner to minimize inter-observer error. Data was analyzed using the Epi Info Statistical software (Epi Info 3.5.1 for Windows, 2008) and SPSS (version 10.0) programme. A p- value of ≤ 0.05 was considered significant.
Results
A total of 968 eyes of 484 eligible participants were analyzed in this study. Multiple regression analysis showed a significant positive correlation between CCT and IOP in the study population (p = 0.002). The linear regression formula for this study was: IOP = 7.87+ (0.016 CCT) mmHg. This indicates that a rise in CCT of 10µm leads to an increase in IOP of about 0.16 mmHg.
Conclusions
Central corneal thickness could result in systematic error in the measurement of IOP by applanation tonometry in the study population. The CCT should therefore, be considered in the management of glaucoma in indigenous Africans in Nigeria.
Keywords: 459 clinical (human) or epidemiologic studies: biostatistics/epidemiology methodology •
568 intraocular pressure