Comparison of IOP Readings Using Rebound I Care Tonometer and Perkins Applanation Tonometer in an African Population

Abstract

Background: Accurate intra ocular pressure (IOP) measurement and monitoring using tonometry is a common clinical measurement in diagnosis and management of glaucoma, this is often a challenge in children. The l Care and Perkins tonometers are both handheld tonometers, Perkins uses applanation while l Care measures IOP with a rebound method Objectives: The objectives of research were to study the IOP values from each tonometer, compare the value of IOP readings from both tonometers, determined the ease of their use in young children and document the various positions in which the tonometers were used successfully in children. Methods: intra ocular pressure readings were taken by two experienced examiners in upright position without sedation or anaesthesia. l Care tonometer was first used. Data were entered and analysed with SPSS 17 statistical package. The means were compared using paired sample T-test. Results: A total of 480 eyes of 240 persons, aged between Zmonths and 90years with a mean of 46.2122 years had their intra-ocular pressure range between 3 and 44mmHg( Mean16.3.+.6) measured using l Care and Perkins tonometry. There was a high correlation, and no statistically significant differences in the mean IOP comparing l Care and Perkins tonometers. The mean difference in average IOP readings between l Care and Perkins was - 00812.8 (95% Cl: 0.45-0.30; r=0.87, p= 0.68) for right eye and »O.15t2.8mmHg (95% Cl -0.53 to 0.23; r=0.86, p=0.44) in the left eye The difference in the average IOP reading from both tonometers was within 2mmHg 288(66.2%) eyes. Among the 147 (33.8%) eyes with a difference in IOP greater than 2mmHg, Perkins was responsible for the higher IOP reading in 76(51.7%) and l Care in 71(48.3%) p=0.56. Among 42 eyes of 21 children aged < 6years, IOP reading was successfully taken in 41(97.6%) and 21(50%) eyes with l Care and Perkins respectively without sedation oranaesthesia. Conclusion: The IOP readings using the l Care tonometer compares well with that of Perkins tonometer. The l Care was easier to use in young children (< 6year olds) without sedation oranaesthesia in this African population.