Deep anterior lamellar keratoplasty for advanced keratoconus: an updated review of indications, techniques and outcomes

ABSTRACTIntroduction The management of keratoconus has been changed significantly due to the advancement of technology in the field of contact lens materials and designs and introduction of new surgical approaches that aim to avoid or postpone corneal transplantation until the advanced stage of the disease. Deep anterior lamellar keratoplasty (DALK) has the advantage of preserving the patient’s own endothelium and eliminating endothelial graft rejection. Since the recent trend is to perform corneal transplantation mainly for severe keratoconus that are not amenable to other less invasive approaches, this review aims to provide an update on the outcomes of DALK in eyes with the advanced stage of keratoconus.Areas covered A comprehensive literature review of studies in English was conducted using the following keywords: “deep anterior lamellar keratoplasty” or “anterior lamellar keratoplasty” or “DALK” and “keratoconus” and “severe” or “advanced.”Expert commentary DALK significantly improves vision and refraction in advanced keratoconus and provides favorable graft survival. Femtosecond laser seems to improve the technique of the DALK procedure, and future developments could improve the reproducibility of DALK even further. However, current data is inconclusive for the benefit of femtosecond laser-assisted DALK for advanced keratoconus.KEYWORDS: Keratoconusadvanced stagecorneal transplantationdeep anterior lamellar keratoplastyDALKDisclaimerAs a service to authors and researchers we are providing this version of an accepted manuscript (AM). Copyediting, typesetting, and review of the resulting proofs will be undertaken on this manuscript before final publication of the Version of Record (VoR). During production and pre-press, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal relate to these versions also. Article highlightsAs surgeons gain more experience and modify their techniques, DALK has emerged as an acceptable alternative to PK for advanced keratoconus when other less invasive approaches have failed to restore vision.Compared to PK, DALK has a superior safety profile as it eliminates the risk of endothelial graft rejection and preserves globe integrity against trauma.Despite improved safety, the visual and refractive outcomes after DALK can be inferior to those achieved after PK in advanced keratoconus eyes.Femtosecond laser has been used for the DALK procedure to increase the rate of successful big-bubble formation, decrease the rate of intraoperative Descemet membrane perforation, and provide better visual and refractive outcomes.Femtosecond laser-assisted DALK in the present form shows limited benefit, therefore, surgical design and parameters still need to be optimized.A medical economics study is required to assess the cost-effectiveness of laser-assisted DALK techniques in this particular subgroup of patients.AbbreviationsAS-OCT=Anterior segment optical coherence tomographyCDVA=Corrected distance visual acuityD=DiopterDALK=Deep anterior lamellar keratoplastymm=Millimeterμm=MicronsOCT=Optical coherence tomographyPK=Penetrating keratoplastyUDVA=uncorrected distance visual acuityDeclaration of interestThe authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.Reviewer disclosuresPeer reviewers on this manuscript have no relevant financial or other relationships to disclose.Figure 1: Flowchart of the literature search depicting the screening process.Display full sizeAdditional informationFundingThis paper was not funded.