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Anales de la Sociedad Mexicana de Oftalmología y Archivos de la Asociación Para Evitar la Ceguera en México

2005, Number 6

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Rev Mex Oftalmol 2005; 79 (6)

Usefulness of the multizone technique in high refractive errors or patients with thin corneas.

Rivodó ZME, Ruiz MJA

Language: Spanish
References: 57
Page: 308-312
PDF size: 261.02 Kb.


ABSTRACT

Purpose: To evaluate efficacy, predictability and safety of Lasik by doing multizone ablation technique in patients with high ametropies and/or thin corneas. We evaluate cuality of night vision subjetively and satisfaction of ours patients.
Material and Methods : We carried out a retrospective, longitudinal study including 66 eyes with high ametropies and/or bordering thin corneas, underwent Lasik usig multizone ablation technique with the Nidek EC 5000 Excimer Laser and the manual Carreazo Barraquer microqueratome. We evaluate the efficacy comparing VA without correction pre and postoperative. Preop BSCVA was compare with postoperative uncorrected VA and the percentaje of eyes wich gain lines of vision was calculate. Predictibility was measured with those eyes within ± 1D . Safety was study comparing the Theorical Transoperatory Bed ( TTB ) versus the Real Pos-op Bed ( RPB ) . We use the Orbscan IIZ Baush & Lonmb .We did the correlation between RPB with multizone versus the theorical bed if we were used the regular one zone laser ablation. A poll was done to all the patients asking for satisfaction, glare and night vision were cuestionated. These two sintoms were correlated with the initial laser optical zone and the pupilar diameter.
Results: Eficacy: 90.9% got 20/40 or better uncorrected. 62% gained lines of vision compared with their preop BSCVA. The efficacy index was 0.91. Predictibility: 84.8% of the eyes were within ± 1D. Pearson correlation between the amount of expected correction and the obtained was 0.96. Safety: The TTB and the RPB showed a P value ‹0.05 and the Pearson correlation of 0.87. The 98.5% of the cases got a RPB over 250μm (range 248-415) . We had only one case were the RPB was 248 1/4m and developed a corneal ectasia . Satisfaction : 89.1 % of patients were satisfacted . 48% had minimal symptoms of glare at night, 8% had mild and only 1.5% had severe glare at night. This symptoms are related with pupilar diameter ›4.3mm in 78% and with the initial laser ablation optical zone used of 4 and 4.5 mm diameter in 60%.
Conclusions : Lasik with multizone laser ablation is effective to treat hight myopia and astigmatism, specially patients with bordering thin corneas. Although , in order to increase efficacy, predictability and safety we strongly recommend to do a transop paquimetry right after the cut flap and before the laser ablation. Besides to created a thin cut flap .We also recommend to do infrared pupilometry preop.


REFERENCES

  1. 1. Puliafito CA, Steinert RF. Deutsch TF. Hillenkamp F, Dehm EJ, Adler CM. Excimer Laser ablation of the cornea and lens. Experimental studies. Ophthalmology 1985; 92– 98:741–748.

  2. 2. Trokel SL, Srinivasan R, Braren B. Excimer Laser Surgery of the cornea. Am J. Ophthalmology 1983; 96:710.

  3. 3. Burlamacchi P. Laser Sources. En: Hillenkamp F, Pratesi R, Sachi CA (ed.). Laser in Biology and Medicine. New York, Plenum, 1980:1-16.

  4. 4. Srinivasan R. Kinetics of the ablative photodecomposition of organic polimers in the far ultraviolet (193 nm). J Vac Sci Technol 1983; B1:923-926.

  5. 5. Rhodes CK. Excimer Lasers, (2a ed). New York, 1984.

  6. 6. Machat JJ, Slade SG, Probst LE. The Art of Lasik. 2a ed. 1999.

  7. 7. Munnerlyn CR y col. Photorefractive keratectomia: A technique for laser refracitve surgery. J Cataract Refract Surg 1988; 14:46-52.

  8. 8. Roberts CW, Koester CJ. Optical zone diameters for photorefracive corneal surgery, Invest Ophthalmology Vsi Sci 1993; 34:2275-2281.

  9. 9. Pedersen. Microkeratomes, Variation in Corneal Flap Thickness. Abstract Number: 616. J Cat Ref Surg 2001.

  10. 10. Dulaney. Laser in situ keratomileusis, Flap/Hinge, Thickness, Predictability, improving. Abstract Number: 205. J Catarsct Refract Surg 2001.

  11. 11. Salz JJ, Azen SP, Bernestein J y col. Evaluation and Comparision of sources of variability in the measurement of corneal thickness with ultrasonic and optical pachymeters. Ophthalmic Surgery 1983; 14:750-754.

  12. 12. Iskander NG, Anderson PE, Peters NT y col. Accuracyof Orbscan pachymetry measurements and D.H.G ultrasound enhacement procedures J. Cataract Refract Surg 2001; 27:681-685.

  13. 13. Yaylali V, Kaufman SC, Thompson HW. Corneal thickness measurements with the Orbscan Topography System and ultrasonic pachymetry. J Cataract Refract Surg 1997; 23:1345-1350.

  14. 14. Malik. Categories: Laser In Situ Keratomileusis, Corneal Thickness, Measurements, Ultrasound pachymetry versus optical scan. Abstract Number: 325. J Cataract Refract Surg 2000.

  15. 15. Cantera. Corneal Topography, Cornea, Thickness . Abstract Number: 872. J Cataract Refract Surg 2000.

  16. 16. Perez Santoya JJ, Bellot J, Claramonte P y col. Laser in situ keratomileusis in high myopia. J Cataract Refract Surg 1997; 23:372-385.

  17. 17. Miller AE, McCulley J.P, Bowman RW, Caravagh HD, Wang XH. Patient satisfaction after Lasik for myopia. CLAO 2001; 27:84-88.

  18. 18. Knorz Mc, Wieisinger B, Lierman A y col. Laser in situ keratomileusis for moderate and high myopia and myopic astigmatism. Ophthalmology 1998; 105:232-940.

  19. 19. McGhee CNJ, Orr D, Kidd B y col. Psychological aspects of Excimer Laser surgery for myopia; reasons for seeking treatment and patient satisfaction. Br J Ophthalmology 1996; 80:874-879.

  20. 1. Puliafito CA, Steinert RF. Deutsch TF. Hillenkamp F, Dehm EJ, Adler CM. Excimer Laser ablation of the cornea and lens. Experimental studies. Ophthalmology 1985; 92– 98:741–748.

  21. 2. Trokel SL, Srinivasan R, Braren B. Excimer Laser Surgery of the cornea. Am J. Ophthalmology 1983; 96:710.

  22. 3. Burlamacchi P. Laser Sources. En: Hillenkamp F, Pratesi R, Sachi CA (ed.). Laser in Biology and Medicine. New York, Plenum, 1980:1-16.

  23. 4. Srinivasan R. Kinetics of the ablative photodecomposition of organic polimers in the far ultraviolet (193 nm). J Vac Sci Technol 1983; B1:923-926.

  24. 5. Rhodes CK. Excimer Lasers, (2a ed). New York, 1984.

  25. 6. Machat JJ, Slade SG, Probst LE. The Art of Lasik. 2a ed. 1999.

  26. 7. Munnerlyn CR y col. Photorefractive keratectomia: A technique for laser refracitve surgery. J Cataract Refract Surg 1988; 14:46-52.

  27. 8. Roberts CW, Koester CJ. Optical zone diameters for photorefracive corneal surgery, Invest Ophthalmology Vsi Sci 1993; 34:2275-2281.

  28. 9. Pedersen. Microkeratomes, Variation in Corneal Flap Thickness. Abstract Number: 616. J Cat Ref Surg 2001.

  29. 10. Dulaney. Laser in situ keratomileusis, Flap/Hinge, Thickness, Predictability, improving. Abstract Number: 205. J Catarsct Refract Surg 2001.

  30. 11. Salz JJ, Azen SP, Bernestein J y col. Evaluation and Comparision of sources of variability in the measurement of corneal thickness with ultrasonic and optical pachymeters. Ophthalmic Surgery 1983; 14:750-754.

  31. 12. Iskander NG, Anderson PE, Peters NT y col. Accuracyof Orbscan pachymetry measurements and D.H.G ultrasound enhacement procedures J. Cataract Refract Surg 2001; 27:681-685.

  32. 13. Yaylali V, Kaufman SC, Thompson HW. Corneal thickness measurements with the Orbscan Topography System and ultrasonic pachymetry. J Cataract Refract Surg 1997; 23:1345-1350.

  33. 14. Malik. Categories: Laser In Situ Keratomileusis, Corneal Thickness, Measurements, Ultrasound pachymetry versus optical scan. Abstract Number: 325. J Cataract Refract Surg 2000.

  34. 15. Cantera. Corneal Topography, Cornea, Thickness . Abstract Number: 872. J Cataract Refract Surg 2000.

  35. 16. Perez Santoya JJ, Bellot J, Claramonte P y col. Laser in situ keratomileusis in high myopia. J Cataract Refract Surg 1997; 23:372-385.

  36. 17. Miller AE, McCulley J.P, Bowman RW, Caravagh HD, Wang XH. Patient satisfaction after Lasik for myopia. CLAO 2001; 27:84-88.

  37. 18. Knorz Mc, Wieisinger B, Lierman A y col. Laser in situ keratomileusis for moderate and high myopia and myopic astigmatism. Ophthalmology 1998; 105:232-940.

  38. 19. McGhee CNJ, Orr D, Kidd B y col. Psychological aspects of Excimer Laser surgery for myopia; reasons for seeking treatment and patient satisfaction. Br J Ophthalmology 1996; 80:874-879.

  39. 1. Puliafito CA, Steinert RF. Deutsch TF. Hillenkamp F, Dehm EJ, Adler CM. Excimer Laser ablation of the cornea and lens. Experimental studies. Ophthalmology 1985; 92– 98:741–748.

  40. 2. Trokel SL, Srinivasan R, Braren B. Excimer Laser Surgery of the cornea. Am J. Ophthalmology 1983; 96:710.

  41. 3. Burlamacchi P. Laser Sources. En: Hillenkamp F, Pratesi R, Sachi CA (ed.). Laser in Biology and Medicine. New York, Plenum, 1980:1-16.

  42. 4. Srinivasan R. Kinetics of the ablative photodecomposition of organic polimers in the far ultraviolet (193 nm). J Vac Sci Technol 1983; B1:923-926.

  43. 5. Rhodes CK. Excimer Lasers, (2a ed). New York, 1984.

  44. 6. Machat JJ, Slade SG, Probst LE. The Art of Lasik. 2a ed. 1999.

  45. 7. Munnerlyn CR y col. Photorefractive keratectomia: A technique for laser refracitve surgery. J Cataract Refract Surg 1988; 14:46-52.

  46. 8. Roberts CW, Koester CJ. Optical zone diameters for photorefracive corneal surgery, Invest Ophthalmology Vsi Sci 1993; 34:2275-2281.

  47. 9. Pedersen. Microkeratomes, Variation in Corneal Flap Thickness. Abstract Number: 616. J Cat Ref Surg 2001.

  48. 10. Dulaney. Laser in situ keratomileusis, Flap/Hinge, Thickness, Predictability, improving. Abstract Number: 205. J Catarsct Refract Surg 2001.

  49. 11. Salz JJ, Azen SP, Bernestein J y col. Evaluation and Comparision of sources of variability in the measurement of corneal thickness with ultrasonic and optical pachymeters. Ophthalmic Surgery 1983; 14:750-754.

  50. 12. Iskander NG, Anderson PE, Peters NT y col. Accuracyof Orbscan pachymetry measurements and D.H.G ultrasound enhacement procedures J. Cataract Refract Surg 2001; 27:681-685.

  51. 13. Yaylali V, Kaufman SC, Thompson HW. Corneal thickness measurements with the Orbscan Topography System and ultrasonic pachymetry. J Cataract Refract Surg 1997; 23:1345-1350.

  52. 14. Malik. Categories: Laser In Situ Keratomileusis, Corneal Thickness, Measurements, Ultrasound pachymetry versus optical scan. Abstract Number: 325. J Cataract Refract Surg 2000.

  53. 15. Cantera. Corneal Topography, Cornea, Thickness . Abstract Number: 872. J Cataract Refract Surg 2000.

  54. 16. Perez Santoya JJ, Bellot J, Claramonte P y col. Laser in situ keratomileusis in high myopia. J Cataract Refract Surg 1997; 23:372-385.

  55. 17. Miller AE, McCulley J.P, Bowman RW, Caravagh HD, Wang XH. Patient satisfaction after Lasik for myopia. CLAO 2001; 27:84-88.

  56. 18. Knorz Mc, Wieisinger B, Lierman A y col. Laser in situ keratomileusis for moderate and high myopia and myopic astigmatism. Ophthalmology 1998; 105:232-940.

  57. 19. McGhee CNJ, Orr D, Kidd B y col. Psychological aspects of Excimer Laser surgery for myopia; reasons for seeking treatment and patient satisfaction. Br J Ophthalmology 1996; 80:874-879.




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