Effect of intraocular lens asphericity on vertical coma aberration
Presented at the 13th winter meeting of the European Society of Cataract & Refractive Surgeons, Rome, Italy, February 2009.
Received 15 May 2009; received in revised form 23 August 2009; accepted 23 August 2009.
Purpose
To analyze the effect of asphericity of intraocular lenses (IOLs) on vertical coma aberration after implantation of spherical, spherically neutral, and aspheric IOLs.
Setting
Department of Ophthalmology, St. Thomas' Hospital, London, United Kingdom.
Method
This observational study recruited patients from previous prospective randomized fellow-eye controlled studies comparing aspheric and spherical IOLs (3 spherical, 1 spherically neutral, and 2 aspheric IOLs). At postoperative follow-up visits, maximum pupil dilation was achieved and aberrometry was performed using an iTrace aberrometer with a pupil scan size of 5.0 mm. Data on Zernike coefficients Z(3,−1) (vertical coma), Z(3,+1) (horizontal coma), and Z(4,0) (spherical aberration) and on IOL power were extracted.
Results
Two hundred eyes of 100 patients were recruited. Ninety-two eyes had a spherical IOL, 32 eyes had a spherically neutral IOL, and 76 eyes had an aspheric IOL. Vertical coma Z(3,−1) and spherical aberration Z(4,0) values were highest with the spherical IOLs and lowest with the aspheric IOLs (P = .0163 and P<.0001, respectively). There was no difference in horizontal coma aberration between the 3 IOL groups. There was no correlation between IOL power and vertical coma aberration (r2 = 0.0135, P = .1169).
Conclusions
Conventional spherical IOLs induced more vertical coma than newer aspheric and spherically neutral IOLs. Vertical coma aberration enhances the depth of focus; thus, newer aspheric and spherically neutral designs of IOLs may negatively affect uncorrected near vision.
Financial Disclosure
No author has a financial or proprietary interest in any material or method mentioned.
From the Department of Ophthalmology, St. Thomas' Hospital, London, United Kingdom
Corresponding author: Mr. David J. Spalton, Department of Ophthalmology, St. Thomas' Hospital, London SE1 7EH, United Kingdom.
Data from previous prospective randomized fellow-eye controlled studies funded by a grant from Alcon Laboratories, Forth Worth, Texas, USA.
ABSTRACT