[Clinical results of the aspheric intraocular lens FY-60AD (Hoya) with particular respect to decentration and tilt].

BACKGROUND

Aspheric intraocular lenses (IOLs) aim to improve visual function and particularly contrast vision by neutralizing spherical aberration. One drawback of such IOLs is the enhanced sensitivity to decentration and tilt, which can deteriorate image quality.

METHODS

A total of 30 patients who received bilateral phacoemulsification before implantation of the aspheric lens FY-60AD (Hoya) were included in a prospective study. In 25 of the patients (50 eyes) the following parameters could be assessed 3 months after surgery: visual acuity, refraction, contrast sensitivity, pupil size, wavefront errors and decentration and tilt using a newly developed device.

RESULTS

The functional results were very satisfying and comparable to results gained with other aspheric IOLs. The mean refraction was sph + 0.1 D (±0.7 D) and cyl 0.6 D (±0.8 D). The spherical equivalent was −0.2 D (±0.6 D). Wavefront measurements revealed a good compensation of the corneal spherical aberration but vertical and horizontal coma also showed opposing values in the cornea and IOL. The assessment of the lens position using the Purkinje meter demonstrated uncritical amounts of decentration and tilt. The mean amount of decentration was 0.2 mm±0.2 mm in the horizontal and vertical directions. The mean amount of tilt was 4.0±2.1° in horizontal and 3.0±2.5° in vertical directions.

CONCLUSIONS

In a normal dioptric power range the aspheric IOL FY-60AD compensates the corneal spherical aberration very well with only minimal decentration. The slight tilt is symmetrical in both eyes and corresponds to the position of the crystalline lens in young eyes. This may contribute to our findings of compensated corneal coma.