METHODS: Fifty consecutive patients(50 eyes)undergone pterygium excision(unilateral nasal, primary pterygium, horizontal length <4mm), and conjunctival autografting were included in this prospective study. IOP measurements were obtained by Rebound tonometry and non-contact tonometry in random order with(lens measurement)and without(native measurement)a bandage contact lens half a month after operation. We compared the mean values(validity parameter)and standard deviation(precision parameter)of the two individual measurements in each case using the paired t-test 14d after surgery.

RESULTS: With the rebound tonometry we detected statistically significant higher values in the contact lens measurements(18.20±3.19 vs 15.17±3.80mmHg in the native measurements; P<0.001), a good correlation with r=0.884 and mean difference was 3.04±1.79mmHg; With the non-contact tonometry we detected statistically significant higher values in the contact lens measurements(15.74±3.23 vs 13.19±3.89mmHg in the native measurements; P<0.001), a good correlation with r=0.876 and mean difference was 2.55±1.88mmHg. In the contact lens measurements and native measurements, we detected statistically significant higher values by Rebound tonometry than that by non-contact tonometry(P<0.001), and mean difference was 2.46±1.45mmHg, 1.98±1.67mmHg.

CONCLUSION: The use of rebound tonometry and non-contact tonometry shows good consistency between lens measurement and native measurement. However, it should be noted that the average of the measurements over contact lens by rebound tonometry and non-contact tonometry were found to be higher than that in native measurement, and the average of the measurements with and without lens by rebound tonometer was found to be higher than what was measured by non-contact tonometry.