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Large-diameter deep anterior lamellar keratoplasty for keratoconus: visual and refractive outcomes
  1. Ting Huang,
  2. Yunwei Hu,
  3. Mengru Gui,
  4. Hong Zhang,
  5. Yun Wang,
  6. Chao Hou
  1. State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
  1. Correspondence to Dr Ting Huang, State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Room 704, Building 3#, District Yuexiu, Guangzhou 510060, China; thuang{at}


Background To investigate the difference in clinical outcomes between large-diameter deep anterior lamellar keratoplasty (L-DALK) and standard DALK (S-DALK) for the treatment of keratoconus.

Methods 132 patients (132 eyes) from the Zhongshan Ophthalmic Center with a clinical diagnosis of keratoconus were enrolled. The participants were featured by the intolerance to rigid gas-permeable contact lenses or unsuccessful fitting of contact lenses. Using stratified blocked randomisation, eligible eyes were allocated into the L-DALK group or the S-DALK group (66 eyes, respectively). Postoperative uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), refractive sphere, manifest cylinder and spherical equivalent refractive error were tested at 6, 12, 18 and 24 months after surgery.

Results After surgery, the L-DALK group had better UCVA and BSCVA than the S-DALK group (p=0.000 and 0.021, respectively). At 24 months, mean BSCVA was 0.17±0.10 logarithm of the minimum angle of resolution (logMAR) (Snellen equivalent, 20/25) in the L-DALK group vs 0.22±0.10 logMAR (Snellen equivalent, 20/32) in the S-DALK group. Differences were observed between the L-DALK group and the S-DALK group in terms of refractive sphere (p=0.015), manifest cylinder (p=0.014) and spherical equivalent refractive error (p=0.034) at any time interval postoperatively. At 24 months, the mean spherical equivalent refractive error was −3.5±3.2 D and −5.2±2.6 D in the L-DALK and S-DALK groups, respectively.

Conclusions L-DALK can reduce the degree of postoperative myopia and manifest astigmatism and improve visual acuity outcomes in keratoconus compared with S-DALK.

Trial registration number Chinese Clinical Trial Registry (TRC-13003122).

  • Cornea
  • Clinical Trial
  • Treatment Surgery

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