Intraocular pressure measurement by three different tonometers in primary congenital glaucoma

Purpose: to determine the agreement between intraocular pressure (iop) measurements using an automated non-contact tonometer (nct),goldmann applanation tonometer (gat),and the ocular response analyzer (ora) in subjects with primary congenital glaucoma (pcg). methods: twenty-nine eyes of 17 pcg patients underwent iop measurements using nct,gat and ora. variables obtained by the ora were corneal-compensated iop (iopcc),goldmann-correlated iop (iopg),corneal hysteresis (ch),and corneal resistance factor (crf). a difference more than 1.5 mmhg for iop was considered as clinically relevant. results: mean age of the patients was 12 years. mean iop (±standard deviation,sd) was 15.3 ± 2.8 mmhg (gat),15.5 ± 6.0 (nct),19.2 ± 7.0 (iopg),and 21.1 ± 7.9 (iopcc); (p = 0.001). except for nct vs. gat (p = 1.0),the average iop difference between each pair of measurements was clinically relevant. the 95% limits of agreements were - 10.2 to 10.3 mmhg (nct vs. gat),-7.8 to 15.3 (iopg vs. gat),and - 8.1 to 19.0 (iopcc vs. gat). the differences in iop measurements increased significantly with higher average iop values (r = 0.715,p = 0.001,for nct vs. gat; r = 0.802,p < 0.001,for iopg vs. gat; and r = 0.806,p < 0.001,for iopcc vs. gat). ch showed a significant association with differences in iop measurements only for iopcc vs. gat (r = 0.830,p < 0.001). conclusion: mean iop obtained by nct was not significantly different from that of gat,but ora measured iops were significantly higher than both other devices.