Correction of Corneal Astigmatism with AcrySof Toric IOL Short

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					      Correction of Corneal Astigmatism with
                 AcrySof Toric IOL:
           Short- and Long-Term Results

                                           Peter Hoffmann
                                        Christoph Lindemann
                                        Karl-Christoph Schulze




Our research has been partially funded by Alcon
                  Introduction
• Astigmatism is common and astigmatic refraction
  errors are routinely treated with toric spectacle
  glasses (69% of all prescriptions in our clinic)
• Corneal astigmatism of 1,5 D or more occurs in 1 out
  of 6 cataract eyes
• Corneal astigmatism contributes 50% or more to the
  postoperative defocus equivalent (size of blur circle
  on the retina)
• Incisional methods of astigmatism correction have
  low predictability and limited range
                              Numbers and Facts
100.00%




     73.70%




          36.04%


               16.57%
                    8.09%
                            4.43% 2.65%
                                          1.56% 0.99% 0.65% 0.43% 0.26% 0.19%



 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 6.00

   Corneal astigmatism present in % of cataract eyes (n = 23239)                Cylindrical part contributes approx. 50% to the
   Cumulative frequency based on Zeiss IOLMaster® keratometry                    defocus equivalent of 3046 refractions post
       e.g. 16,57% have 1,5 D or more, 2,65% 3,0 D or more                                      cataract surgery
             Patients and methods
•   Prospective, single-arm study
•   84 patients with 102 eyes enrolled
•   50 right, 52 left eyes
•   89 eyes fully evaluated
•   Median 73 years (range 37-86), no „best case“ picking
•   2 surgeons with 10 year, 300+ cases experience with toric IOL
•   Corneal astigmatism 1,25 to 3,0 D
•   No significant ocular pathology apart from cataract
IOL power spherical equivalent and torus
        No. of eyes implanted




  Spherical equivalent (D)   T3=1,5D   T4=2,25D   T5=3,0D
                                         Torus
                 Surgical technique
• Zeiss IOL-Master® biometry + Pentacam Hires topography
• IOL calculation according to Haigis
    – Calculation of spherical equivalent lens power
    – Calculation for steep and flat meridian seperately,
      difference = IOL torus required, always rounded down to
      avoid overcorrection
• Marking of horizontal axis at sitting patient with Gerten
  marker
• Microcoaxial phaco (Geuder) with 2,5 or 2,2 mm posterior
  limbal stab incision
• Marking of cornea with Neuhann marker prior to
  implantation
• Final rotation and positioning of the lens after removal of
  OVD
• Crosscheck by retinoscopy („poor man‘s wavefront analysis“)
Results: Cylinder pre/post [dpt]
Visual acuity UCVA / BSCVA
 Cylinder pre/post double angle scatter plot




4 weeks                     6 months
Prediction error spherical equivalent / cylinder




 Prediction error (spherical equivalent)         Predictability of cylindrical correction

Haigis constants a0=−0.091 a1=0.231 a2=0.179
   as published on ULIB website for SA60AT

+ more hyoperopic − more myopic than predicted
Malpositioning (axis intended − achieved)      Measured rotation of the lens axis




 Magnitude of vector change of cylinder     Surgically induced astigmatism (Naeser)
                                           Discussion
•     good refractive outcome of cataract surgery (uncorrected visual acuity) is very
      important for patient satisfaction
•     implanting a toric IOL is the most reliable option for correcting astigmatism during
      cataract surgery
•     approx. 97% of all eyes can be corrected with IOL cylinder up to 3,0 D
•     with proper planning and technique, median absolute positioning error of 3° or less
      is achievable
•     limbal microincisions give extremely low SIA, noise due to measuring tolerances
•     postop. cylinder typically reduced to 0,5 dpt
•     very good efficacy, UCVA typically only one line less than BSCVA
•     very good predictability of cylindrical effect
•     very good predictability of spherical equivalent, but „constants“ not identical to
      SA60AT, refractive results should be reviewed on a large scale and constants fine-
      tuned (e.g. A=118,9 instead of 118,7 for SRK/T users)
•     lens rotation negligible and well within measuring tolerance
•     stable refraction over time, no spherical shift, cylindrical vector change negligible,
      compares favorably to FDA trial results*
    * http://www.fda.gov/cdrh/pdf/p930014s015.html