Comparative study of keratoconus between Anwar's deep anterior lamellar keratoplasty versus converted penetrating keratoplasty

Five-year Outcomes of Converted Mushroom Keratoplasty from Intended Deep Anterior Lamellar Keratoplasty (DALK) Mandate 9-mm Diameter DALK as the Optimal Approach to Keratoconus

“…22 This may account for why there was not a single episode of graft failure in the MK group secondary to endothelial decay in the absence of rejection. In comparison to other studies which have reported no worse outcomes for their cohorts converted to PK compared to uncomplicated DALK, 6,9 the greater failure rates of 4/68 (5.88%) in MK cohort is fact more consistent with reported failures rates of DALK in the literature. 6,23 One failure was due to traumatic dehiscence, one due to infection and two were subsequent to episodes of endothelial rejection (Table 4B); all were regrafted with good outcomes.…”

“…15,16 Nevertheless, DALK still has a relatively high rate of conversion to full thickness keratoplasty; 16.4% in this series and between 14.9-35.3% in others. 6,9,15 In such cases, conversion to a 9mm PK is significantly larger than the conventionally considered optimal compromise of 8-8.25mm diameter full-thickness grafts, sized to simultaneously minimize postoperative refractive error and the risk of immunologic rejection. 7 A strategy to manage conversion from DALK to PK has therefore evolved using a two-piece mushroom shaped graft, which aims to minimize the endothelium transplanted in these keratoconic patients with otherwise healthy host endothelium to a 6mm posterior lamella, 8 whilst still benefitting from the wide anterior lamellar refractive surface of 9mm.…”

“…The outcomes of conventional PK when compared with DALK as primary procedures have been well reported. 8,9 However, there is generally a lack of evidence as to whether the outcomes in eyes that were intended to undergo DALK yet required conversion to PK are worse than those that had successfully completed DALK. 6,9 In particular, studies have not compared long term clinical and refractive outcomes for wide diameter grafts.…”

“…8,9 However, there is generally a lack of evidence as to whether the outcomes in eyes that were intended to undergo DALK yet required conversion to PK are worse than those that had successfully completed DALK. 6,9 In particular, studies have not compared long term clinical and refractive outcomes for wide diameter grafts. In order to routinely attempt wide diameter DALK, confidence that the respective outcomes of such patients are comparable to planned DALK is imperative.…”

Deep anterior lamellar keratoplasty for keratoconus

“…Intraoperative macroperforation of the Descemet's membrane may require conversion to PK in 15%–35% of cases. [ 28 29 30 31 ] Occurrence of a type 2 bubble, manual dissection, presence of scarring and surgeon inexperience have been identified as independent risk factors for the need to conversion of intended DALK to PK. [ 31 ] Should conversion to PK be required, rather than a 9-mm PK, a two-piece mushroom keratoplasty may be performed.…”