Jornal de Oftalmologia Clínica e Experimental
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Optical Aberrations and Contrast Sensitivity of Spherical and Aspheric Intraocular Lenses - A Prospective Comparative Clinical Study

Nada Jirásková, Juraj Urminský, Vera Lorencova, Alena Feuermannova, Alexandr Stepanov and Pavel Rozsíval

Purpose: To compare visual acuity, aberrometry, and contrast sensitivity in eyes with spherical intraocular lens (IOL) and aspheric IOL implanted after uncomplicated phacoemulsification.
Setting: Department of Ophthalmology, University Hospital, Hradec Králové, Czech Republic.
Methods: A prospective clinical study involving 90 patients (105 eyes) having cataract surgery, with implantation of spherical IOL AcrySof Natural (SN60AT) in 45 patients (50 eyes) with a mean age of 62.5 years, and aspheric IOL AcrySof IQ (SN60WF) in 45 patients (55 eyes) with a mean age of 64.5 years. A control group involved 22 eyes of similar age with clear lens crystallina. Postoperatively, visual acuity (ETDRS charts), aberrometry (ORK Wavefront Analyser, Schwind), and contrast sensitivity tests (CSV 1000, Contrast Sensitivity 8010 System) were evaluated. Statistical analyses were performed using Student t-test.
Results: No statistical differences were found regarding visual acuity among eyes. A lower level of higher order aberrations was achieved in the aspheric group. In the contrast sensitivity test, no statistical differences between groups under photopic conditions were noted. In mesopic conditions better performance was observed in eyes with aspheric IOLs, mainly in low spatial frequencies (statistically significant). The control group (lens crystallina) was better in all frequencies.
Conclusions: Cataract surgery outcomes cannot be measured by means of visual acuity alone. In this study, the aspheric IOLs AcrySof IQ (SN60WF) demonstrated better visual function, especially contrast sensitivity in low spatial frequences, when compared with spherical IOLs AcrySof Natural (SN60AT).