Systematic review comparing penetrating keratoplasty and deep anterior lamellar keratoplasty for management of keratoconus.
OBJECTIVE
Perception of reduced incidence of graft rejection after deep anterior lamellar keratoplasty (DALK) has attracted many surgeons towards this technique in keratoconus. This review aims to compare the visual, refractive and graft outcomes after penetrating keratoplasty (PK) and DALK for keratoconus.


METHODS
Electronic searches of PubMed, MEDLINE, EMBASE, Latin American and Caribbean Health Sciences Literature database (LILACS), metaRegister of Controlled Trials (mRCT), ClinicalTrial.gov and the WHO International Clinical Trials Registry Platform (ICTRP) were performed. We included randomized control trials (RCTs) and comparative studies to assess primary and secondary outcomes after PK and DALK in eyes with keratoconus. Primary outcome was best-corrected visual acuity (BCVA) LogMAR at ≥6 months. Secondary outcomes included number of patients with BCVA≥0 LogMAR, uncorrected visual acuity (UCVA) LogMAR, spherical equivalent (SE), refractive and keratometric astigmatism, endothelial cell density (ECD) cell/mm2, graft rejection and graft survival.


RESULTS
Eighteen studies (including 2 RCTs) compared DALK (965 eyes) and PK (2402 eyes) for keratoconus. There was strong evidence through RCTs suggesting better LogMAR BCVA at ≥6 months and better LogMAR UCVA with PK; reduced refractive astigmatism and rejection with DALK and no difference in SE and keratometric astigmatism. Moreover, there was weak evidence to suggest better BCVA≥0 LogMAR after PK and no difference in ECD between the two techniques.


CONCLUSIONS
Despite the popularity of DALK amongst corneal surgeons for keratoconus, there is a paucity of high quality RCTs. The existing limited evidence confirms reduced rejection and refractive astigmatism with DALK but better visual outcomes with PK. Internationally agreed data sets and follow-up protocol are warranted.
Sussex Eye Hospital, Brighton & Sussex University H ospitals NHS Trust, Eastern Road, Brighton, BN6 5BF, United Kingdom.
Christin
C
Henein
Sussex Eye Hospital, Brighton & Sussex University H ospitals NHS Trust, Eastern Road, Brighton, BN6 5BF, United Kingdom. Electronic address: mayank.nanavaty@bsuh.nhs.uk.
Mayank A
MA
Nanavaty
D000328:Adult; D015984:Causality; D015897:Comorbidity; D016039:Corneal Transplantation / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000175:diagnosis / Q000453:epidemiology* / Q000601:surgery*; D015948:Keratoplasty, Penetrating / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology* / Q000517:prevention & control; D016896:Treatment Outcome; D014786:Vision Disorders / Q000175:diagnosis / Q000453:epidemiology* / Q000517:prevention & control
DALK; Keratoconus; PK