الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Deep anterior lamellar Keratoplasty (DALK) is a surgical method that
completely removes pathologic corneal stroma tissue down to the Descemet’s
membrane, followed by transplantation of donor cornea without endothelium over
the host bed.
New techniques that use viscoelastic substance and air to directly expose
Descemet’s membrane have dramatically reduced surgery time, while improving
the safety of performing surgery.
The indications for DALK have expanded for almost all cases of corneal opacity
that have a healthy endothelial cell count, with a comparable visual outcome to
penetrating Keratoplasty. Endothelial graft rejection is absent after DALK.
However, stromal graft rejection, although rare, does occur.
The aim of this study was to evaluate the visual outcomes and complications of
deep anterior lamellar keratoplasty (DALK) using the big-bubble technique in
patients with keratoconus.
This non comparative interventional case study series that was carried out on 47
eyes of 46 patients presented with moderate to advanced keratoconus for DALK
from December 2012 up to June 2014.Average follow up 12 months. Best
spectacle-corrected visual acuity (BSCVA), refractive status, and intra- and
postoperative complications were evaluated.
Thirty-seven procedures (78.7%) were completed with Big-bubble formation; 6
(12.8%) required manual intrastromal dissection. Intraoperative microperforations
occurred in 4 cases (8.5%). Baseline mean preoperative BSCVA was
0.036±0.017and final BSCVA at one year has a mean value of 0.38 (P < 0.001). Postoperative mean spherical equivalent refractive error and refractive astigmatism
were -4.9±2.6 and -3.9±1.6 D, respectively. Main complications encountered
included Loosening of the stitches observed in 11 cases (23.4%), stitches
vascularization in 3 cases (6.4%), double anterior chamber occurred in two cases
(4.3%), Urrets-Zavalia syndrome occurred in one case (2.1%), Stromal rejection
noticed in one case (2.1%), and suture abscess in one case (2.1%).
In conclusion: DALK using the big-bubble technique appears to be a safe and
effective procedure in patients with keratoconus. Postoperative myopic refraction
is observed in most cases.
DALK has a good long-term graft survival rate, and, because it is an extraocular
procedure, it is safer than PK. Further improvements in DALK techniques will
likely enhance its usefulness for treatment of corneal disease in patients with noncompromised
endothelium.