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[Deep lamellar keratectomy using the big-bubble technique in patients with keratoconus].

PURPOSE
To evaluate patients with keratoconus 12 months after deep anterior lamellar keratectomy using the big-bubble technique.


METHODS
A retrospective study of 79 consecutive eyes of 71 patients with moderate to severe keratoconus with visual impairment after optical correction and intolerant to contact lens fitting. All transplants were performed by the same experienced surgeon, from January 2007 to February 2009 using the technique of deep anterior lamellar keratectomy by big-bubble. Data analyzed were gender, age, corneal pachymetry, endothelial cell density, dynamic astigmatism and best correct visual acuity after keratectomy.


RESULTS
Mean age was 30,4 (± 10.2) years, 39 (54,9%) were female and 32 (45,1%) male. The ultrasonic pachymetry average was 518.6 (± 29.5) μm. Seventy-two (91.1%) had a best dynamic corrected visual acuity better or equal to 20/50. Mean dynamic astigmatism was - 3.5 (± 1.5) spherical diopters. The mean endothelial cell density found according to age distribution had patients between 11-20 years with 3,053 (± 532) cel/mm(2); 21-30 years with 2,674 (± 25) cel/mm(2); 31-40 years with 2,737 (± 575) cel/mm(2); 41-50 years with 2,585 (± 476) cel/mm(2) and 51-60 years with 2,398 (± 667) cel/mm(2). Microperfurations had incidence of 8,8%.


CONCLUSION
The deep anterior lamellar keratectomy using the big-bubble technique is a valuable treatment for patients with keratoconus, reaching a final best correct visual acuity similar to penetrating keratoplasty. The mean endothelial cell count is within the normal range for age after the procedure. No rejection or corneal edema were noted after all points' removal. The dynamic astigmatism in deep anterior lamellar keratectomy is similar to that found in reports of penetrating keratoplasties. Deep anterior lamellar keratectomy using the big-bubble technique must be studied as the first option for the treatment of keratoconus.