Comparison of the optical quality of foldable intraocular lenses before and after injection using a double-pass system

MERITXELL VILASECA; MONTSERRAT ARJONA; JAUME PUJOL; LUIS ISSOLIO; JOSÉ GUELL

JOURNAL OF CATARACT AND REFRACTIVE SURGERY.

Elsevier

Lugar: USA; Año: 2009 vol. 35 p. 1415 - 1423

0886-3350

PURPOSE: This study evaluates and compares the in vitro optical quality of several foldable monofocal intraocular lenses (IOLs) commonly used to correct aphakia. To evaluate the lenses, the double-pass technique is used at two different stages: before and after injection. The optical quality of the lenses is assessed under the same conditions as those commonly used for in vivo measurements. METHODS: We objectively evaluated the in vitro optical quality of six different IOLs before and one hour after the injection with their company recommended injectors in an artificial eye attached to a conventional double-pass system. The IOLs were immersed in physiological serum to simulate in vivo conditions. The procedure imitated the conventional procedure used to assess the optical quality of real implanted eyes. The retinal image quality achieved at each stage by each lens was analyzed in terms of the following optical parameters, all of which were provided by the system: the point spread function (PSF), the modulation transfer function (MTF), the MTF cut-off frequency, the Strehl ratio, and the OQAS values at contrasts of 100%, 20% and 9%. In order to test the repeatability and reproducibility of the system, six measurements of each lens were carried out at each stage. Statistical analysis was performed with a t test for the repeated measurements. RESULTS: The results show that the in vitro optical quality of most of the IOLs remained as good after injection as before. Only one of the studied IOLs had a statistically significant difference in optical quality after injection. The results also demonstrate that the eye cell model associated with the double-pass system is a useful and effective technique for fully characterizing the optical quality of IOLs and evaluating their variation with regard to the injection process. CONCLUSION: The double-pass results show that, in general, the injection of a foldable IOL into an eye does not affect the eye’s imaging quality. Therefore, when the lens is placed inside the eye’s structure, good optical performance is ensured, allowing good vision quality in the patient.