1. Clinical outcome of DALK in Keratoconus – A one year follow up
Authors: Somasheila I Murthy, MD, Smruthi rekha Priyadarshini, MD, Jagadesh Reddy, MD
and Prashant Garg, MD.
Affiliation: Cornea and anterior segment service,
L. V. Prasad Eye Institute, Kallam Anji Reddy Campus, Hyderabad, India
The authors have no financial interest in the subject matter of this poster

2. Methods
Study purpose: To evaluate the visual outcome and complications of deep anterior lamellar keratoplasty (DALK) in keratoconus
Study design: retrospective interventional case series
Study location: Cornea and anterior segment service, LV Prasad eye Institute, Hyderabad, India
Inclusion criteria: all cases of keratoconus that underwent DALK with a minimum follow-up of one year
Pre-operative evaluation included:
Visual acuity
Slit lamp examination
Central corneal thickness
Corneal topography

3. Methods The data obtained included: pre and post-operative:
Best corrected Snellen’s visual acuity
Slit-lamp examination for assessment of graft clarity
Central corneal thickness
Corneal topography using Orbscan
Anterior segment optical coherence tomography post-operatively in some cases
Surgical technique:
2 techniques:
Big-bubble technique
Manual dissection in layers
Combination
Primary outcome measures:
Visual acuity
Graft clarity
Secondary outcome measures:
Nonprogression of keratoconus
Graft failure due to edema or rejection
Complications rate

4. Results During 2004 to 2008, 49 eyes of 48 patients underwent DALK
Table 1: Age distribution
During 2004 to 2008, 49 eyes of 48 patients underwent DALK
Twenty-two eyes completed one year follow-up
Mean age: (range 11 to 43 years) with 77% under 20 years
Fifteen were male and seven female patients
Age
Eyes (%)
11 – 20 yrs
17 ( 77%)
21 – 30 yrs
2 (9%)
31 – 40 yrs
2 (9 %)
> 40 yrs
1(4.5%)

5. Results: pre and post-operative visual acuity
Table 2: Pre-operative visual acuity
Table 3: Post-operative visual acuity
Visual acuity
> 20/ 60
Eyes 6
20/60 – 20/ 200 4
20/200 – 20/400 3
<20/400
13 (60%)
Visual acuity
20/20-20/40
Eyes
16 (73%)
20/40-20/60 2
20/60-20/80
< 20/80

6. Results Corneal thickness ranged from 427 to 591 microns
Table 4: Surgical technique
Big bubble 7
Manual lamellar dissection 3
Combination 12
Total 22
Corneal thickness ranged from 427 to 591 microns
Donor graft size ranged from 7.5 to 10.5

7. Results: graft clarity and complications
Table 5: Graft clarity
Table 6: Complications
Clear graft
16 (73%)
Interface haze 2
Scarring 3
Pigments on endothelium 1
Suture related 9
Vascularisation 3
PAS 1
None 8

8. Summary
Best-corrected visual acuity at one year was 20/40 or better in 16/22 cases (73%)
16/22 cases had clear graft, with 5/22 showing interface haze or scarring
No major complications like glaucoma, graft failure or progression were noted
Minor suture related complications (loose or broken sutures) were noted in 9 eyes (40%)

9. Discussion
Penetrating keratoplasty is the accepted surgical treatment for keratoconus and has an excellent five-year graft survival rate1,2
However, it can fail due to allograft rejection and endothelial cell loss
Deep anterior lamellar keratoplasty replaces anterior diseased part of the cornea while retaining the host endothelium and has the advantage of reducing the risks of graft rejection and intraocular complications

10. Discussion
Various authors have reported their results of DALK and have shown comparable visual acuities with PK with fewer post-operative complications3, 4, 5 Our study also shows similar results
Therefore, despite this technique being more demanding surgically, it is worthwhile to perform DALK for keratoconus and PK should be done only as a last resort

11. Conclusions
Visual acuity outcomes of DALK in keratoconus are good in majority of cases
In comparison to penetrating keratoplasty, there are fewer post-operative complications and majority encountered were minor
DALK is perhaps the preferred choice for the surgical management of keratoconus

12. References:
Pramnik S, Musch DC, Sutphin JE, Farjo AA. Extended long-term outcomes of penetrating keratoplasty for keratoconus. Ophthalmology 2006;113:
Zadok D, Schwarts S, Marcovich A, et al. Penetrating keratoplasty for keratoconus: long term results. Cornea 2005;24:
Watson SL, Ramsay A, Dart JKG, et al. Comparison of deep lamellar keratoplasty with penetrating keratoplasty in patients with keratoconus. Ophthalmology, 2004;111:
Sarnicola V, Toro P, Gentile D, et al. Descemetic DALK and pre-descemetic DALK: outcomes in 236 cases of keratoconus. Cornea Jan;29(1):53-9
Han DY, Mehta JS, Por YM et al. Comparison of outcomes of lamellar keratoplasty and penetrating keratoplasty in keratoconus. Am J Ophthalmol 2009;148(5):629-31