Efficacy of double-incision extracapsular cataract extraction in the treatment of hard-nucleus cataract with low corneal endothelial cell density

Abstract

Objective: To discuss the efficacy and security of double-incision extracapsular cataract extraction (ECCE) in the treatment of hard-nucleus cataract with low corneal endothelial cell density. Methods: This was a retrospective case series study. Forty-six patients (47 eyes) with hard-nucleus cataract and low corneal endothelial cell density were enrolled at Shandong Eye Hospital from June 2009 to December 2018, including 22 males and 24 females, aged 50 to 74 (63.8±6.3) years. Preoperative corneal endothelial cell density was less than 1 000 cells/mm(2), and the cataract nuclear hardness was equal to or greater than grade IV. According to the surgical methods, the patients were divided into the single-incision ECCE group (24 eyes) and the double-incision ECCE group (23 eyes). The surgical procedures for the double-incision group were as follows. First, a superior scleral pre-incision was made. Then the conventional capsulorhexis was conducted through a 2.6 mm transparent corneal tunnel incision at the temporal or the nasal side, after which the hydro-dissection was performed. Next, the surgeon cut the pre-incision at the sclera, delivered the lens nucleus, sutured the scleral incision and removed the residual cortical materials from the corneal incision. Finally, a foldable intraocular lens was implanted, and the viscoelastic substance was removed. The intraoperative anterior chamber condition and the postoperative corneal edema condition were monitored. During the 6 month follow-up after surgeries, the endothelium cell density, visual acuity and astigmatism in the two groups were compared. The χ(2) test was used to compare the counting data, and the t test was used to compare the measurement data. Results: There was no statistically significant difference (t=1.12, P=0.28) in the preoperative corneal endothelial cell density between the double-incision and single-incision ECCE groups, which was (827±164) cells/mm(2) and (802±121) cells/mm(2), respectively. At 6 months after operation, in the double-incision and single-incision groups, the endothelial cell density was (793±147) cells/mm(2) and (706±101) cells/mm(2), respectively, and the difference was statistically significant (t=4.37, P<0.01). The percentage of corneal endothelial cell loss was 4.16%±3.12% and 11.69%±2.96%, respectively, and the difference was also statistically significant (t=9.52, P<0.01). The hexagon loss rate of corneal endothelial cells was 9.67%±6.11% and 28.33%±8.39%, respectively, and the difference was statistically significant (t=5.52, P<0.05). In the follow-up of 6 months, none of the eyes in the double-incision ECCE group suffered corneal endothelial decompensation compared with 3 eyes in the single-incision ECCE group. There were no statistically significant differences in postoperative astigmatism and surgically induced astigmatism between the two groups (t=-0.71, 0.15; P>0.05). Conclusions: The double-incision ECCE, in which the lens nucleus is delivered through a scleral incision and other procedures are conducted through a corneal tunnel incision, is safe and effective for cataract patients with hard nucleus and low corneal endothelial cell density. (Chin J Ophthalmol, 2020, 56: 126-130).