OBJECTIVE: To evaluate the results of deep anterior lamellar keratoplasty (DALK) using dissection with air or with a viscoelastic substance in the surgical treatment of keratoconus as an alternative to penetrating keratoplasty. MATERIAL AND METHODS: This prospective monocentric noncomparative study involved patients with contact lens-intolerant keratoconus operated on between February 2001 and September 2002. Deep lamellar dissection was performed either by air injection into the cornea to create a white emphysema of the stroma or by viscoelastic injection. This allows the surgeon to separate Descemet's membrane from the posterior stroma using the air-to-endothelium interface. Previously, aqueous humor was replaced by air in the anterior chamber to visualize the posterior corneal surface. A full-thickness allogenic corneal button was sutured into the recipient bed, after stripping its Descemet's membrane. RESULTS: Fifteen eyes of 15 patients (mean age, 41.2 years) underwent DALK. The mean preoperative visual acuity was 0.11+/-0.06. At 1 year, the mean best corrected visual acuity was 0.47+/-0.16 (p<0.001). Mean keratometric astigmatism was reduced from 6.97+/-3.3 D to 2.77+/-1.76 D at 1 year (p<0.001). Specular microscopy 3 months postoperatively revealed average endothelial cell counts of 2018+/-662/mm2, while 1 month preoperatively this value was 2604+/-235/mm2 (cell loss, 22.5%; p>0.05). Perforation of Descemet's membrane during surgery occurred in five eyes (33.3%). Two cases were converted to penetrating keratoplasty. There was no endothelial rejection. CONCLUSION: In this series, DALK appears to be a promising procedure for treatment of keratoconus with encouraging refractive outcome, no progressive primary graft failure, and no allogenic endothelial graft rejection. DALK is an interesting alternative for penetrating keratoplasty even if it is technically more difficult.
OBJECTIVE: To evaluate the results of deep anterior lamellar keratoplasty (DALK) using dissection with air or with a viscoelastic substance in the surgical treatment of keratoconus as an alternative to penetrating keratoplasty. MATERIAL AND METHODS: This prospective monocentric noncomparative study involved patients with contact lens-intolerant keratoconus operated on between February 2001 and September 2002. Deep lamellar dissection was performed either by air injection into the cornea to create a white emphysema of the stroma or by viscoelastic injection. This allows the surgeon to separate Descemet's membrane from the posterior stroma using the air-to-endothelium interface. Previously, aqueous humor was replaced by air in the anterior chamber to visualize the posterior corneal surface. A full-thickness allogenic corneal button was sutured into the recipient bed, after stripping its Descemet's membrane. RESULTS: Fifteen eyes of 15 patients (mean age, 41.2 years) underwent DALK. The mean preoperative visual acuity was 0.11+/-0.06. At 1 year, the mean best corrected visual acuity was 0.47+/-0.16 (p<0.001). Mean keratometric astigmatism was reduced from 6.97+/-3.3 D to 2.77+/-1.76 D at 1 year (p<0.001). Specular microscopy 3 months postoperatively revealed average endothelial cell counts of 2018+/-662/mm2, while 1 month preoperatively this value was 2604+/-235/mm2 (cell loss, 22.5%; p>0.05). Perforation of Descemet's membrane during surgery occurred in five eyes (33.3%). Two cases were converted to penetrating keratoplasty. There was no endothelial rejection. CONCLUSION: In this series, DALK appears to be a promising procedure for treatment of keratoconus with encouraging refractive outcome, no progressive primary graft failure, and no allogenic endothelial graft rejection. DALK is an interesting alternative for penetrating keratoplasty even if it is technically more difficult.