Analysis of an Approach to Astigmatism Correction during Cataract Surgery

Abstract

Purpose: To determine if a system of astigmatic keratomy at the time of cataract surgery is safe and effective. Setting: Academic Ophthalmology Center. Methods: One hundred and ten consecutive patients with greater than 0.50 diopters (d) of cylinder with the rule (WTR) and 0.75 d against the rule (ATR) were enrolled. Those with an axis between 16 and 74° and 106 and 164° were defined as oblique axis. Peripheral clear corneal relaxing incisions 600 µm deep were used with a nomogram of 60° length per 1.0 d of attempted correction. Keratometry was taken from IOL Master biometry and refractive results at 4–12 weeks were compared. Results: 60.5% of ATR, 62% of WTR and 23% of oblique attempted correction was achieved. Splitting the patients to under and over 70 years of age had no impact on the results. Of the 14 overcorrected, 7 had oblique cylinder (p = 0.009) and 10 had less than 1 d of preoperative cylinder (p = 0.00015). Conclusions: Using the IOL Master topography with this nomogram was quite effective in reducing preoperative cylinder. Oblique axis results were unpredictable, however, and much more likely to lead to an overcorrection.

Correction of astigmatism at the time of cataract surgery

“…Reliance on the IOLMaster (Zeiss-Humphrey, Dublin, California, USA) alone is reported to overcorrect certain types of astigmatism [1]. Topographic measurement of corneal astigmatism is currently the standard of care.…”

Corneal Astigmatic Correction by Femtosecond Laser Incisions

“…There are a number of PCRI nomograms for correcting small amounts of cylinder and many studies evaluating the efficacy of PCRIs that have been performed [8][9][10][11][12][13][14][15][16][17][18][19]. In one study on the effectiveness of PCRIs, there was a 60 % average reduction of cylinder [20], with 79 % of patients corrected to less than 1.00 D of cylinder and 59 % corrected to less than 0.5 D of cylinder. The 60 % reduction in cylinder compares favorably with the results achieved using toric IOLs, which result in a mean 58.4 % reduction in cylinder [21].…”

A Pilot Study To Compare Using Verion Imaging Guided System (Alcon) To Manual Marking In Assisting LRI (Limbal Relaxation Incision) To Reduce Cylinder Power In Cataract Surgery

“…LRI appears most suitable for management of low astigmatism, whereas greater levels of astigmatism are likely best treated by use of toric lenses with or without the addition of arcuate incisions. Additionally, LRIs correct the astigmatism at the source within the cornea, making them potentially effective for asymmetric corneal astigmatism where toric lenses are unable to benefit [10]. Even the long-term higher-order aberration was not altered by the LRI [11].…”