Soft Contact Lens Effect on Intraocular Pressure Measurement

Soft contact lenses (SCLs) are utilized for therapeutic purposes and correction of refractive errors. Where SCLs removal is not ideal and routine intraocular pressure (IOP) measurements are required, the need may arise for IOP measurements to be done with SCLs in situ. The aim of this study was to determine soft contact lenses effect on IOP measurement. 42 subjects with mean age of 22.56 ±2.83 were included in the study. Baseline IOP was taken in right eye (OD), first with a Goldmann applanation tonometer (GAT) and then with the Keeler non-contact tonometer (NCT). The 42 subjects were then grouped into 7, each group comprised 6 subjects each group wore 0.00D, +3.00DS, +6.00DS, +9.00DS, -3.00DS, -6.00DS and -9.00DS Opticom SCLs on their OD. IOP was measured with NCT after 30 minutes of wearing these SCLs over the cornea of the OD. The IOP of the naked left eyes of the 42 subjects was also measured with NCT after 30 minutes. This served as an internal control. The data obtained were analysed. Results showed no statistical difference between the baseline mean values of IOP measured with NCT and GAT. The IOP values were significantly greater (p =0.007; p=0.000) for the groups with plus SCL powers of +6.00D and +9.00D respectively and significantly reduced (p =0.019; p=0.005) for the groups with minus SCL powers of -6.00D and -9.00D of Opticom SCLs respectively.