A silicone aspheric intraocular lens (IOL) reduces spherical aberration and enhances contrast sensitivity in low light compared with a conventional spherical IOL, according to a study published in the June 2009 issue of American Journal of Ophthalmology.
Sixty-two eyes of 31 patients who underwent bilateral cataract surgery were evaluated. Patients received a Tecnis Z9000 silicone aspheric IOL in one eye and a CeeOn 911A silicone spherical IOL in the other eye. Both intraocular lenses are made by Abbott Medical Optics (AMO). Follow-up exams were performed at 1, 3, 6 and 12 months after surgery.
Though both the aspheric and spherical IOLs provided essentially the same uncorrected and best-corrected visual acuity in bright and medium-light conditions, the eyes with the aspheric IOLs had fewer higher-order aberrations (specifically, spherical aberration) and exhibited better contrast sensitivity in low-light conditions, the study authors said.
Improved contrast sensitivity in such conditions suggests the Tecnis Z9000 aspheric IOLs may provide sharper vision than conventional spherical IOLs for activities such as driving at night.
Silicone aspheric IOLs generally are considered to be premium intraocular lenses. As such, your cataract surgery cost typically will be higher if you choose these lenses, and the cost of the lenses may not be fully covered by Medicare and other types of vision insurance.
Tags: aspheric, intraocular lenses, IOLs