Abstract
Purpose: :
To test the relationship between the tilts of intraocular lens (IOL) and the coma aberrations in the eyes with cataract surgery.
Methods: :
A Scheimpflug photography-based system (the Pentacam) was used to measure corneal aberrations and IOL positions for 11 eyes (5 right eyes and 6 left eyes) of 9 old adults (mean age = 72.8±8.1 yrs). All IOLs were model AR40e from AMO, Inc. 12 Scheimpflug images along 12 meridians for each Pentacam measurement were exported from the system and processed to derive the heights of the cornea and the IOL at the 12 meridians. After correcting image distortions caused by both projection and refraction, the anterior and posterior corneal surfaces were reconstructed and lateral and vertical coma aberrations of the two corneal surfaces were derived through MatLab ray-tracing and Gram-Schmidt procedures. Lateral and vertical tilts of the IOL were calculated with the Gram-Schmidt procedures from the corrected and reconstructed IOL surfaces. A Hartmann-Shack wavefront sensor (the WASCA) was used to measure the coma aberrations in the whole eye. By subtracting the corneal comas from that in the whole eye, the coma aberrations in the internal optics were calculated. Relationship between the coma aberrations and the IOL tilts was statistically examined.
Results: :
The measured surface radius of the anterior IOL surface was highly correlated to the refractive power of the IOL indexed by the company (r = -0.98, p<0.0001). The lateral coma in the internal optics was also highly correlated to the lateral tilt of the IOL (r = -0.94, p<0.0001). The correlation between the vertical coma of the internal optics and the vertical IOL tilt was approaching significance (r = -0.54, p = 0.089).
Keywords: intraocular lens • aberrations • imaging/image analysis: clinical