*5.2.3.2 Deep anterior lamellar keratoplasty (DALK)*

The visual outcomes of BCVA, UDVA for DALK remains debated. The recent data from systematic review and meta-analysis demonstrated that the visual outcomes were worse [90] or better [81] than those for PK. The outcomes of DALK for keratoconus are better than PK [81] or equivalent [81] in terms of refractive error, astigmatism and rejection rate. Fifty percent of eyes may encounter Descemet membrane perforation which is the most significant intra-operative complications [18]. Other complications such as a double anterior chamber and persistent corneal edema have been reported. DALK may be less prone to secondary ocular hypertension because of their lower steroid requirement (owing to the smaller risk of rejection) [18]. Another advantage DALK is the lack of endothelial rejection because there is no endothelial defense reaction [15]. The reported rates of postoperative complications such as graft rejection, secondary glaucoma, complicated cataracts, and constant endothelial cell loss are lower with DALK than PK [15].


*Adapted from JAMA Ophthalmol. 2014 Apr 1;132(4):495–501.*

*The classification of keratoconus was based on Krumeich JH et al.A. Live-epikeratophakia for keratoconus. J* 

*Cataract Refract Surg. 1998 Apr;24(4):456–63. [17]*

*Stage 1 Kmax < 48 D, thickness > 500* μ*m, absence of scarring.*

*Stage 2 Kmax 48–53 D, thickness 400–500* μ*m, absence of scarring.*

*Stage 3 Kmax 54–55 D, thickness 200–400* μ*m, absence of scarring. Stage 4 Kmax > 55 D, thickness < 200* μ*m, central corneal scarring.*

#### **Table 5.**

*Management algorithm in various stages of keratoconus.*
