Purpose: To report the clinical performance characteristics of single-piece acrylic Alcon SA30AL and SA60AT intraocular lenses (IOLs).
Setting: A private practice in Marshalltown, Iowa, USA.
Methods: In a review of 2630 consecutive cases operated on from January 2000 through July 2001, ease of IOL insertion and integrity of the haptic architecture were evaluated in a prospective fashion at implantation. Subgroups of cases were studied prospectively to evaluate 3 factors: same-day incision competence after implantation (postoperative intraoperative pressure [IOP], 107 cases); 2- to 5-week A-constant validation (200 cases); 1-day, 2-week, and 1- and 5-month descriptions of optic centration with respect to pupil and capsule anatomy (79 cases); and a 1-day versus 9-month photographic comparison of IOL centration (70 cases). A retrospective evaluation of the population's diagnostic codes tabulated complications including increased postoperative iritis, cystoid macular edema, neodymium:YAG (Nd:YAG) laser intervention for posterior capsule opacification, and pseudophakic dysphotopsia. A retrospective review of a subgroup of 140 consecutive cases was done to categorize postoperative optic clarity.
Results: Overall, the IOLs were easy to implant with no haptic or optic damage using a forceps or the Monarch injector. Subgroup studies confirmed good performance in the following parameters: There were no cases of incision incompetence evidenced by an abnormally low postoperative IOP. The lowest postoperative IOP was 6 mm Hg, with the overall mean IOP increasing to 29 mm Hg from the 17 mm Hg measured a mean of 102 minutes after surgery. The manufacturer's published A-constant was almost identical to that obtained in review (118.4 versus 118.38 for the SA30AL and 118.35 for the SA60AT). In verbal descriptions, IOL optic centration was assessed to be within 0.4 mm of perfect in 75 (95%) of 79 cases. Slitlamp photographs showed that 52 (98%) of 53 IOLs were in the same position 9 months after surgery as on the day of surgery. One IOL optic appeared to rotate 14 degrees. There were no cases of decentration greater than 1.0 mm in either optic centration subgroup. Given a normal postoperative topical steroid regimen, there were no cases of substantially increased or prolonged iritis. There were 17 cases (0.65%) of macular edema. An Nd:YAG laser posterior capsulotomy was performed in 0.64% (13/2044) in the SA30AL group over a mean of 9 months (range 2 to 23 months) and in 0.34% (2/586) in the SA60AL group over a mean of 5.5 months (range 5 to 6 months). Pseudophakic dysphotopsia was diagnosed in 26 eyes of 18 patients (1% of 2630 cases), with 1 patient requiring an IOL exchange. Optic glistenings were observed in 11 (11%) of 100 SA30AL cases at a mean follow-up of 8 months. No glistenings in 40 cases were seen in the SA60AT group at a mean follow-up of 3 months.
Conclusions: The single-piece acrylic lenses performed well in all regards. Although not as intense as observed with the earlier 3-piece designs, pseudophakic dysphotopsia occurred in a few patients with the single-piece acrylic lens. Intraocular lens exchanges with single-piece IOLs may be accomplished with less difficulty early rather than late.