The relationship between capsulorhexis size and anterior chamber depth relation

BACKGROUND AND OBJECTIVE: To determine whether the diameter of the capsulor hexis has an effect on anterior chamber depth (ACD) following phacoemulsifi cation surgery. PATIENTS AND METHODS: Fifty-one consecutive patients were selected for cata ract extraction by phacoemulsification with intraocular lens (IOL) implanta tion. Twenty-two of 51 patients underwent 4 mm capsulorhexis, while the res t underwent 6 mm. All were implanted with a multi-piece polymethyl methacry late posterior chamber IOL with 5.0 mm diameter biconvex optic and flexible haptic. They were followed 3 months postoperatively. The width of the caps ulorhexis was assured according to the IOL optic implanted intraoperatively , and by the help of slit-lamp measurement after dilatation of the pupil on the first postoperative day. ACD and axial length (AL) of patients was obt ained by ultrasonography on both the days before surgery, and the first and seventh postoperative days, and after 30, 60 and 90 days. RESULTS: Early significant increase of ACD and ACD/AL ratios were observed in only the 6 mm capsulorhexis group on the first day postoperatively (P = .012, and P = .018). On the 90th postoperative day, ACD increased significa ntly both in the 4 mm (P = .002) and the 6 mm capsulorhexis groups (P = .04 9) when compared to preoperative values. For the same period, meaningful in crease in ACD/AL ratio in the eyes with both 4 mm and 6 mm capsulorhexis gr oups was also noted compared with preoperatively (P = .002 and P = .019). T here was a statistical difference between the 90th day ACD values of 4 mm ( 3.73 +/- 0.32 mm, mean +/- standard deviation) and 6 mm capsulorhexis group s (3.50 +/- 0.33 mm) (P = .028). For the same period, ACD/AL ratio was also significantly different for both groups (0.152 +/- 0.01, and 0.142 +/- 0.0 1 respectively) (P = .004). The refractive error changes followed the ACD c hanges and showed meaningful differences between Ist and 90th days postoper ative values of each group (P = .029, and P = .014, respectively). CONCLUSION: A 4 mm capsulorhexis results in a longer postoperative ACD than does a 6 mm capsulorhexis for the IOL type used in this study.