Pneumatic Dissection for Large-Diameter (9-mm) Deep Anterior Lamellar Keratoplasty in Eyes With Previous Anterior Lamellar Keratoplasty

Abstract

To evaluate the surgical and 3-year clinical outcomes of modified big-bubble 9-mm deep anterior lamellar keratoplasty (DALK) in eyes with previous ALK (ALK). Methods:In this interventional case series, 21 consecutive eyes with unsatisfactory vision after ALK (superficial ALK n = 9; laserassisted ALK n = 7; and epikeratophakia n = 5) underwent largediameter (9-mm) DALK. The surgery involved deep trephination based on the anterior segment optical coherence tomography pachymetry measurement at 9-mm diameter, pneumatic dissection from the base of the trephination and limited stromal clearance of the optical zone (6 mm). Main outcome measures were success rates of pneumatic dissection, best spectacle-corrected visual acuity, and complication rates.Results: Pneumatic dissection with type 1 bubble formation succeeded in 19 (90%) eyes. In the 2 remaining cases, the 6-mm optical zone was cleared by manual dissection. Perforation occurred in one of the latter cases; no procedure was converted to penetrating keratoplasty. One month after complete suture removal, the preoperative mean best spectacle-corrected visual acuity (0.75 6 0.23 logMAR) improved to 0.09 6 0.10 logMAR (P , 0.001) and remained stable up to 3 years after surgery. At the final follow-up, refractive astigmatism was #4.5 and ,6 D in 20 (95%) and 21 (100%) eyes, respectively. Stromal rejection was observed in 2 eyes (10%) and was treated successfully with steroids.Conclusions: Even in eyes with previous ALK, pneumatic dissection can be achieved through a modified DALK technique with a low risk of complications and excellent visual and refractive outcomes.

High Astigmatism After Conventional Diameter Deep Anterior Lamellar Keratoplasty in Keratoconus Can Be Successfully Managed With Repeat Wide Diameter Deep Anterior Lamellar Keratoplasty

“…Anterior segment optical coherence tomography is useful in such eyes to further qualify interface irregularity, with subsequent management primarily being targeted toward replacing the dysfunctional host interface component, rather than purely addressing astigmatism. Pneumatic dissection at a deeper level can be reattempted in such eyes 22 or, if that is not successful, the interface in the optical zone can be excised altogether with 2-piece mushroom keratoplasty. 23 Finally, if the original plane of dissection was pneumatically achieved, the bubble nature is important.…”

Outcomes of Conventional 8.0-mm Versus Large 9.0-mm Diameter Deep Anterior Lamellar Keratoplasty for Keratoconus

“…Unlike published literature, which does not always distinguish the outcomes of cases that achieved exposure of pre-Descemet layer through pneumatic dissection, the current study provides evidence that the use of large-diameter 9.0-mm grafts can directly translate to improved visual and refractive outcomes after DALK. Although large-diameter DALK theoretically reduces the rate of recurrence of corneal stromal ectasia by increasing the area of excision of diseased stroma, 26,27 studies with extended longitudinal follow-up would be required to establish the long-term benefits of this technique.…”

Large-diameter deep anterior lamellar keratoplasty: A narrative review

“…Regardless of the disease severity or the presence of scarring and/or neovascularization, it is reasonable to attempt DALK than to have never given each patient with isolated anterior corneal pathology a fair chance to receive the better surgical option. In challenging cases including inflammatory corneal disease, herpetic keratitis,[ 37 ] intracorneal ring segments,[ 38 ] previous radial keratotomy,[ 39 ] anterior lamellar keratoplasty,[ 40 41 ] and even previous Descemet stripping automated endothelial keratoplasty (DSAEK) surgery,[ 42 43 ] large-diameter DALK can be performed to maximize the refractive benefit of a large-diameter graft while minimizing the risk of endothelial failure. In post-PK eyes with recurrence of stromal disease, large-diameter DALK can be performed through stromal peeling along a natural plane of separation.…”