AIM: To compare the refraction error(RE)3mo after phacoemulsification combined with intraocular lens implantation(PHACO+IOL)between patients with acute primary angle-closure glaucoma(APACG)with cataract(APACG group)and patients with simple cataract(cataract group), and the biological parameters of the eye(axial length,corneal curvature, anterior chamber depth)associated with the postoperative RE in the APACG and cataract groups.

METHODS: This was a prospective, non-randomized, case-control study. Each group had 30 cases(30 eyes). Intraocular pressure, axial length, corneal curvature, and anterior chamber depth were measured. The reserved refractive power was calculated using the SRK-II formula. Three months postoperatively, subjective RE was calculated as the postoperative refractive power which subtracted the preoperative reserved diopter(RE was considered as <-0.50D or >+0.50D; -0.50D to +0.50D not considered as RE). An independent sample t-test was used to compare the difference in RE between the two groups and to compare the differences among relevant parameters such as axial length, corneal curvature, and anterior chamber depth. Paired t-test was used to compare preoperative and postoperative parameters such as axial length, corneal curvature, and difference in anterior chamber depth.

RESULTS: Mean RE in the cataract group was -0.46D±0.46D, with 24 cases of myopic RE(80%)and 6 cases of hyperopic RE(20%). Mean RE in the APACG group was +0.56D±0.79D, with 9 cases of myopic RE(30%)and 21 cases of hyperopic RE(70%). The difference in RE between the two groups was statistically significant(P<0.05). On comparison of pre- and postoperative biological parameters of the two groups, in the cataract group, there was a non-significant difference in pre- and postoperative axial length(23.55±0.47mm versus 23.56±0.48mm, respectively; P>0.05). In the APACG group, pre- and postoperative axial length was 21.71±0.46mm and 21.52±0.54mm, respectively; the difference was statistically significant(P<0.05). In the both the cataract and APACG groups, postoperative anterior chamber depth was significantly higher than preoperative(4.09±0.38mm versus 2.71±0.24mm, in the cataract group, and 3.55±0.35mm versus 1.90±0.23mm, In the APACG group, respectively; both P<0.05). In the cataract group and the APACG groups, pre- and postoperative average corneal curvature were not significantly different(43.93D±0.95D versus 43.92D±0.95D, in the cataract group, and 44.71D±0.84D versus 44.70D±0.9D, In the APACG group, respectively; P>0.05). On comparison of biological parameters between the two groups, postoperative ocular axial length shortening in the APACG group was statistically significant compared with the ocular axial changes in the cataract group(P<0.05). The postoperative anterior chamber deepened markedly in the APACG group; this was statistically significant compared with the cataract group(P<0.05).

CONCLUSION:Postoperative RE in patients with APACG and cataract who underwent PHACO+IOL is relatively large compared with patients with simple cataracts. These patients with APACG and cataract also show hyperopia drift, which is more significantly correlated with postoperative ocular axial length shortening and increased anterior chamber depth.