Big Bubble Deep Anterior Lamellar Keratoplasty For Keratoconus Using An Ab Interno Needle Approach

We describe a modified technique of Big Bubble Deep Anterior Lamellar Keratoplasty (DALK) using an ab interno needle approach. 

The study was conducted at the Department of Ophthalmology, Ospedali Privati Forlì, "Villa Igea", Forlì, Italy.

This study reviews the surgical video of a DALK using a modified ab interno needle approach in a 28-year-old male with advanced keratoconus. Preoperative Best spectacle-corrected visual acuity (BSCVA) was 20/100 and keratometric astigmatism was 8.9 diopters. Based on the anterior segment Optical Coherence Tomography, thinnest point pachymetry was 282 µm. DALK was performed as follows: a temporal paracentesis was performed, and a single air bubble was injected intracamerally. A 31-gauge needle connected to an air-filled syringe was then inserted bevel down from the limbus at 12 o’clock position into the anterior chamber and tangentially into the posterior cornea ensuring that the bevel was completely inserted prior to air injection. Following creation of a big bubble, partial thickness trephination was performed and the surgery was completed as in our standardized big bubble 9mm DALK technique. Postoperatively, the graft was completely attached and double anterior chamber formation was not observed. One year after the surgery, Snellen BSCVA was 20/32 with keratometric astigmatism of 3.4 diopters. The corneal graft was clear with no evidence of graft rejection or failure. Endothelial cell count was 2220/mm².

DALK using an ab interno needle approach is a feasible method for achieving pneumatic dissection. This approach ensures deep insertion of the needle for pneumatic dissection and allows performance of DALK without the need for special ad hoc surgical instruments.