Variable Depth Arcuate Astigmatic Keratotomy in Kerato – Lenticulo – Plasty
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- Category: Vol. 77, June 2009
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Variable Depth Arcuate Astigmatic Keratotomy in Kerato – Lenticulo – Plasty, MAHMOUD M. GAMAL
Abstract
The purpose of this study was to introduce and evaluate the a new concept in surgical correction of preexisting corneal astigmatism (PEA) by using the variable depth dependent arcuate astigmatic keratotomy (AK) combined with 3.2mm clear corneal cataract incision (CCI) for cataract surgery.
Subjects and Methods: Arcuate AK was performed on 17 eyes of 15 patients for correction of low and moderate levels of regular corneal PEA. All procedures were performed by the same surgeon. The preoperative astigmatism ranged from one to 4.5 diopters (D) (means 2.12±1.31). They were divided into three sub groups; Group 1 (included 6 patients with PEA of <1.25 D), Group 2 (included 5 patients with PEA between 2.00 and 1.25D) and group 3 (included 6 patients with PEA >2.25D). The size of the optical zone (7mm) and the number, and lengths of the transverse incisions (one pair of 90º arc) were constant. The intended depth of the arcuate AK was varied according to the level of attempted preoperative astig-matism correction. The primary outcome measures included preoperative and postoperative manifest refraction. The sec-ondary outcome measures were: Visual outcome [unaided and best-corrected visual acuity (UAVA, BCVA)] and any compli-cations.
Results: The results were evaluated using both simple analysis and vector analysis methods. Patients were seen on the first postoperative day and thereafter at 1st month and 3rd month. One pair of AK cuts, at the 7.0mm optical zone, with a depth of 60% of the local corneal thickness produced an astigmatic correction of 0.46 D. The pair at 70% depth pro-duced astigmatic correction of 0.75D and the AK cuts at 80% produced correction of 1.83D. The elimination of spherical error was recorded in 92.8% of cases. After surgery, astigma-tism was reduced to a mean of 1.15D (range 0 to 2.25D). The mean decrease in astigmatism was 1.03D. The mean of axis shift was 6.58±18.18D. The difference between the achieved axis and the desired axis was less than 10º in 70% of the cases and less than 20º in 90% of the cases. None of the cases showed any reduction in the BCVA.
Conclusion: Results indicated that PEA in cataract cases can be corrected, or at least, effectively reduced by variable depth transverse arcuate AK simultaneously with CCI. Pre-dictable results can be achieved with this technique. A sim-plified nomogram is included.