原发性急性闭角型青光眼合并白内障超乳术后的屈光误差及其相关影响因素

目的：对比原发性急性闭角型青光眼(acute primary angel-closure glaucoma，APACG)合并白内障患者及单纯白内障患者行PHACO+IOL术后3mo的屈光误差(refraction error， RE)，并分析影响两组术后屈光误差相关的眼球生物学参数(眼轴、角膜曲率、前房深度)。

方法：前瞻性、非随机性病例对照研究。APACG合并白内障组为试验组，单纯白内障组为对照组，每组各30例30眼，测量眼压、眼轴长度、角膜曲率、前房深度，利用SRK-Ⅱ公式计算预留屈光度。以术后3mo的主觉验光结果作为术后屈光度，减去术前预留屈光度，即为屈光误差(RE，<-0.50D或>+0.50D； -0.50～+0.50D不认为存在屈光误差 )。采用独立样本t检验比较两组间屈光误差的差别及比较两组间的相关参数如眼轴、角膜曲率、前房深度的差异，采用配对样本t检验分别比较两组术前术后相关参数如眼轴、角膜曲率、前房深度的差异。

结果：白内障组术后的平均屈光误差为-0.46±0.46D，其中近视性屈光误差共24例(80%)，远视性屈光误差共6例(20%)； APACG组术后的平均屈光误差为+0.56±0.79D，其中近视性屈光误差共9例(30%)，远视性屈光误差共21例(70%)，两组术后屈光误差的差异具有统计学意义(P<0.05)。两组内的术前术后生物参数比较：白内障组术前眼轴长度23.55±0.47mm，术后23.56±0.48mm，眼轴长度变化差异无统计学意义(P>0.05)； APACG组术后的眼轴长度21.52±0.54mm，较术前的眼轴长度(21.71±0.46mm)变短，差异有统计学意义(P<0.05)。白内障组术后前房深度4.09±0.38mm，较术前前房深度(2.71±0.24mm)明显增加，差异有统计学意义(P<0.05)； APACG组术后的前房深度3.55±0.35mm，较术前前房深度(1.90±0.23mm)明显增加，差异有统计学意义(P<0.05)。白内障组术前平均角膜曲率43.93±0.95D，术后43.92±0.95D，平均角膜曲率变化差异无统计学意义(P>0.05)； APACG组术前平均角膜曲率44.71±0.84D，术后44.70±0.9D，平均角膜曲率变化差异无统计学意义(P>0.05)。两组间的相关生物参数比较：APACG组术后眼轴变短，与单纯白内障组眼轴变化量比较，差异有统计学意义(P<0.05)； APACG组术后前房加深明显，与单纯白内障组前房加深量比较有统计学意义(P<0.05)。

结论：对比单纯白内障患者，APACG合并白内障患者行PHACO+IOL术后的屈光误差大，且呈远视漂移，与APACG患者术后眼轴变短及前房深度增加更明显相关。

Analysis of the refraction error and the influencing factors after phacoemulsification in acute primary angle-closure glaucoma with cataract

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.