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Deep anterior lamellar keratoplasty techniques; predescemetic versus big bubble: Anterior segment optical coherence
S Genc1, M Emin Sucu1, S Çakmak1
1Department of Ophthalmology, Beyoglu Eye Training and Research Hospital, University of Health Sciences, Istanbul, Turkey.
Purpose:
To compare the visual and refractive outcomes and anterior segment optical coherence tomography (AS-OCT) findings of 2 different deep anterior lamellar keratoplasty (DALK) techniques in the treatment of advanced keratoconus with and without successful big bubble formation.
Methods:
In this retrospective comparative case series, data from 79 consecutive eyes of 69 patients who underwent either big bubble (group 1, n: 62) or manual DALK (group 2, n: 17) were analyzed. The visual and refractive results, keratometric values and residual stromal thickness were assessed. Patients were seen at 1, 3, 6 and 12 months after the procedure and 1 month after complete suture removal.
Results:
A big bubble was successfully obtained in 62 eyes (78.5%; group 1) and manual dissection was performed in the 17 remaining eyes (21.5%; group 2). The final best spectacle-corrected visual acuity (BSCVA) was 0.38 logMAR and 0.55 logMAR in Group 1 and 2, respectively (P<0.05). At the final visit, BSCVA≤0.30 logMAR was achieved in 80% and 60.8% of eyes in Groups 1 and 2, respectively (P<0.001). Groups 1 and 2 were comparable in terms of mean keratometry: 47.80D±2.81D (range, 41.30D to 54.2D) versus 45.90D±3.62D (range, 41.10D to 53.8 D), respectively; (P=0.56) and keratometric astigmatism: 3.81D± 2.1D (range, 1.0D to 6.20D) versus 3.56D±1.92D (range 1.2D to 6.85D), respectively; (P=0.40) at the final follow-up. The mean residual stromal thickness was 36.90±17.80μm in group 2.
Conclusion:
The presence of residual posterior corneal stroma when big bubble formation is not successfully achieved in DALK is correlated with lower postoperative visual acuity.
