Semi-automatic Evaluation of Intraocular Lenses (IOL) Using a Mechanical Eye Model

摘要

As cataracts are the most common reason for loss of vision with an age over 55, the implantation of intraocular lenses is one of the most common surgical interventions. The quality measurement and test instructions for IOL are denned in the ISO 11979-2. However, the optical imaging quality of the implanted IOL is not always satisfactory for the patients. Therefore more efforts are put into the individualization of IOL in order to achieve better imaging properties. Two examples of typical quality standards for IOL are the modulated transfer function (MTF) and the Strehl ratio which can be measured in vivo or also in mechanical eye models. A mechanical eye model in the scale 1:1 is presented. It has been designed to allow the measurement of the MTF and Strehl ratio and simultaneous evaluation of physiological imaging quality. The eye model allows the automatic analysis of the IOL especially focused on the tolerance for tilting and decentering. Cornea, iris aperture and IOL type are interchangeable, because all these parts are implemented by the use of separated holders. The IOL is mounted on a shift plate. Both are mounted on a tilt plate. This set-up guarantees an independent decentration and tilt of the IOL, both moved by electrical drives. This set-up allows a two-dimensional tolerance analysis of decentration and tilt effects. Different 100×100 point (decentration × tilt) analyzes for various iris apertures, needing only approximately 15 minutes, are presented.