Guerrero BO, Baca O, Velasco R, Viggiano D, Calvillo ABM

Language: Spanish
References: 11
Page: 301-307
PDF size: 109.09 Kb.

ABSTRACT

Purpose: To compare the incidence, type and grade of induced and residual astigmatism with Lasik, with the flying spot technology and the variable scan spot, in cases of myopic astigmatism and simple myopia. Materials: A comparative, prospective/retrospective study, including 2 groups: Group 1. 120 eyes treated with Visx Star S2 and Group 2. 86 eyes treated with LadarVision. The calculation of the induced and residual astigmatism was made with a vectorial analysis at the first and third month. % cylinder correction, axial deviation and visual outcome were also considered for the analysis. Results: Group 1: The mean residual astigmatism was 0.87 x 177 and 0.55 x 178.8 at the 1^st and 3^rd month. The mean induced astigmatism was 1.82 x 180 at the 3^rd month. Group 2: The mean residual astigmatism was 0.63 x 175.8 and 0.84 x 179.6 at the 1^st and 3^rd month. The mean induced astigmatism at the 3^rd month was 1.39 x 10.5. The final correction of the cylinder was better in the first group. The visual outcome and the axial deviation was similar in both goups. Conclusion: The major grade of induced astigmatism presented occured with the variable scan spot group, wich correlates with its low incidence of residual astigmatism. Finally, the visual outcome was similar in both groups.

REFERENCES

1. McDonald M y col. Laser in situ Keratomileusis for Myopia up to - 11 Diopters with up to - 5 diopters of Astigmatism with the Summit Autonomous LADARVision Excimer Laser System. Ophtalmology 2001; 108(2):309-316.

2. 2. Swami A y col. Rotational Malposition during Laser in Situ Keratomileusis. Am J Ophtalmol; 133(4): 561-562.

3. 3. Holladay J y col. Evaluating and Reporting Astigmatism for Individual and Aggregate Data. J Cataract Refractive Surg 1998; 24:57- 65.

4. 4. Barroso A y col. Vector Analysis of Surgically Induced Astigmatism After Lasik. IOVS 2001; 42(4).

5. 5. Stevens JD y col. Astigmatic Excimer Laser Treatment: Theoretical Effects of Axis Misalignment. Eur J Implant Refrac Surg 1994; 6:310-318.

6. 6. Thompson V. Clinical Experience with the Alcon Summit Autonomous LADARVision Eye Tracking System. Rev Refrac Surg 2002; 24-25.

7. 7. Hersh, y col. Incidence and Associations of Retreatment After LASIK. Ophthalmology 2003; 110:748-754.

8. 8. Rodriguez-Prats J y col. Induced Astigmatism after Laser in Situ Keratomileusis. J Cat Refrac Surg; 29(2): 414-415.

9. 9. Soloway BD, Roth RE. Laser in Situ Keratomileusis in a patient with Congenital Nystagmus. J Cat Refrac Surg 2002; 28(3):544-546.

10. 10. Huang D y col. Mathematical model of Corneal Surface Smoothing After Laser Refractive Keratomileusis. Am J Ophthalmol 2003; 135(3):267-278.

11. 11. Giaconi J y col. Ablation centration in myopic laser in situ keratomileusis comparing the Visx S3 ActiveTrak and the Visx S2. J Cat Refrac Surg 2003; 29:1522-1529.