Data from 1 year of follow-up in a 2-year study demonstrate a favorable clinical performance of a microincisional IOL designed for implantation through a 1.8 mm incision.
"The microincision lens is demonstrating good efficacy with best-corrected visual acuity [BCVA] results in accordance with historical control rates, favorable safety with rates of FDA grid cumulative and persistent adverse events not significantly higher than historical control rates, and excellent in-the-bag stability," said Dr. Behndig, assistant professor, department of clinical science/ophthalmology, Umeå University Hospital, Umeå, Sweden.
The single-piece hydrophilic acrylic posterior chamber IOL features a spherical aberration-free optic to provide excellent quality of vision, four haptics designed to maintain stable capsular bag centration, and a 360° posterior square-edge optic barrier to limit posterior capsule opacification (PCO).
Patients were operated on between August 2006 and October 2007. Planned follow-up is to 2 years and data from the 1-year visit (postop days 330 to 420) were available from 113 patients.
The study participants reflected a typical cataract population with a mean age of 69 years. A wide range of cataract density was represented with 33% of lenses rated as dense to very dense and the rest as slight to moderate. The lens powers implanted ranged from 15.5 to 30 D with an average of 21.2 D.
Phacoemulsification was performed using a biaxial microincision technique through an average incision size of 1.5 mm. Topical anesthesia was used in all eyes and 72% of surgeries involved a clear corneal incision. Capsulorhexis diameter ranged from 4 to 6 mm and the capsulorhexis rim overlapped the optic in 96% of eyes.
The IOL was delivered using a wound-assisted technique and a lens delivery system (ViscoJect, Medicel) with a 1.8-mm cartridge. Incision measurement showed IOL delivery resulted in stretching of about 0.1 mm. The incisions were hydrated at the end of the case and almost all were left sutureless (94.4%), Dr. Behndig said.
Analyses of manifest subjective refraction data showed excellent outcomes and stability over time with mean values of –0.06 D at the first follow-up visit (1 to 2 weeks postop) and –0.08 D at the 1-year exam. Patients also benefited from rapid recovery of vision that was maintained during the first year after surgery. However, because not all cases were targeted for emmetropia, uncorrected visual acuity was better than 20/40 in only about three-fourths of eyes.
"BCVA data are a better indicator of efficacy and show that our BCVA outcome of 20/40 or better in 96.2% of eyes at 6 months exceeds the FDA historical control rate of 92.5%," he said.