Big bubble DALK and keratoconus

Better outcomes in big bubble DALK for keratoconus when sutures remain in place

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Mouamen M. Seleet MD, FRCS
Big bubble deep anterior lamellar keratoplasty (DALK) is effective and reproducible and delivers very good refractive and visual outcomes for the surgical treatment of moderate-to-advanced keratoconus, according to Mouamen M. Seleet MD, FRCS. “While the outcomes are good, we do need to bear in mind that the refractive changes after the removal of sutures remains unpredictable. However, based on our experience we can say that in cases of good refractive outcomes it is a safer bet to leave the sutures in than to remove them and that will help to achieve a better final visual acuity,” Dr Seleet told delegates attending the World Ophthalmology Congress in Barcelona. A procedure such as big bubble DALK provides a smooth interface by cleaving the stroma from Descemet’s membrane, thereby preventing the irregularities of the stromal interface and the stromal scarring that can occur with manual dissection, noted Dr Seleet. His prospective non-randomised study included 105 consecutive eyes over 18 months and was designed to assess big bubble DALK in terms of efficacy, reproducibility, safety and the effect of removal of sutures on visual acuity and corneal astigmatism. Almost all patients (94%) were available for analysis after 12 months, and 84% were available at 18 months. One-quarter of patients (25%) were suture-in and 59% were suture-out. All corneas had single running 12-bite sutures with 
the same size donor and recipient buttons from 8mm 
to 8.5mm. “The indications for suture removal at 12 months after DALK was if the refractive cylinder was more than 4.0D, if there was an anisometropia, suture-related complications or planned secondary refractive surgery,” said Dr Seleet. The uncorrected distance visual acuity (UDVA) was closely matched for suture-in versus suture-out patients at six months, but the picture shifted when the patients were assessed at 12 months. “Those patients that were destined to have their sutures out started to show a decrease of their UDVA while the suture-in patients showed an improvement at 12 months. This difference increased after the final removal of the sutures at 18 months,” he said. Similarly, the corrected distance visual acuity (CDVA) also showed that patients destined to have their sutures in showed better visual acuity than those destined to have sutures out. Refractive cylinder outcomes were also significantly better in the suture-in group, added Dr Seleet. Adverse events in the study included a failed bubble in 10 eyes (9.5%), microperforation in six (6.7%), near Descemet dissection in five (4.8%), delayed epithelial healing in three (2.9%), steroid-induced glaucoma in 11 (10.5%), traumatic wound rupture in four (3.8%), cataract in three (2.9%) and stromal rejection in six (5.7%). Broken sutures were also seen in two patients, but neither of them had to be converted to penetrating keratoplasty, he said. Mouamen M. Seleet: mouamenseleet@gmail.com