CLINICAL EVALUATION OF INTRAOCULAR PRESSURE MEASUREMENTS USING DIFFERENT TONOMETERS IN PATIENTS OF VARIOUS REFRACTIVE ERRORS

ABSTRACT

Background: Intraocular pressure (IOP)is an important ?rst indicator of probability and suspicion of Glaucoma. The virtual IOP status is grossly in?uenced by multiple factors including Refractive errors ,corneal biomechanics ,central corneal thickness(CCT) and Scleral rigidity. To compare relative IOP measurements and Aim: its variability in Emmetropes, myopic and hypermetropic patients using Schiotz, Goldmann Applanation(GAT)and I-Care Rebound tonometer to establish an equation between virtual and real time IOP. This observational Materials and Methods: prospective study comprised of 100 subjects above the age of 18 years inclusive37 Emmetropes , 31 Hypermetropes and remaining 32 belonged to myopia . Descriptive statistics were performed using SPSS for Windows Statistical Analysis: version 17.0 to calculate the demographic characteristics of the study cohort. The data were expressed as mean values including the standard deviation (SD) and the 95% con?dence interval (CI). Mean IOP measurements between Schiotz, I-Care and GAT were compared by One way ANOVA along with Individual pair wise comparison by applying Post Hoc Tukey Test for comparison of IOP measurements using a particular method of Tonometry in individuals of myopia, hypermetropia and emmetropia. The highest mean value of CCT 536.667 mum was in Hypermetropes whereas the lowest CCT value of Results: 507.031mum was in myopic eyes with statistically signi?cant (P<0.05). The mean value for IOP in Emmetropes was16.665 mm Hg for Schiotz , 15.027 Hg for GAT and 15.081 mm Hg for I –Care .Whereas Hypermetropes revealed mean value of 15.055 mm Hg for Schiotz , 14.323 mm Hg for GAT and 14.065 mm Hg for I –Care . The mean value for IOP in Myopic eyes was 16.875 mm Hg for Schiotz , 14.375 mm Hg for GAT and 14.688 mm Hg for I –Care . The study had revealed higher mean Conclusion: value of IOP in Myopic eyes as compare to Emetropic and Hypermetropic subjects.IOP measurements by the Schiotz tonometer were signi?cantly higher as compare to GAT and I-Care tonometer. Whereas recordings by GAT and I Care tonometers were almost in agreement .De?nitive correlation could not be established between pachymetry readings and adjusted IOP following GAT and I –Care tonometry .