‘Big bubble’ technique offers visual results, recovery time similar to PK

PARIS — The “big bubble” technique for lamellar keratoplasty offers surgeons a safe and consistent alternative to penetrating keratoplasty in selected cases, said Mohamed Anwar, MD. He described his results with the technique here at the European Society of Cataract and Refractive Surgeons meeting.

Endothelial and stromal rejection are rarely seen with the technique, and graft survival is long-term, Dr. Anwar said.

“Rejection of the bubble is virtually nil,” he said. “There is no immune rejection because the host endothelium is retained.”

To execute the technique, the surgeon places an air bubble at the posterior edge of the stroma to separate the stroma from Descemet’s membrane. The surgeon should use a 27-gauge to 30-gauge needle to insert the air bubble, he said.

The surgeon must be aware the air bubble will raise IOP to around 50 mm Hg or 55 mm Hg, he said, “so you don’t want it there for long.” The time the air bubble remains in place should be limited to 15 or 20 minutes.

Dr. Anwar reported results of the big bubble technique in 547 eyes of 409 patients; 316 of the eyes had keratoconus, 93 had superficial scars, 87 had climatic keratopathy, 45 had corneal dystrophy, 24 had pellucid marginal degeneration and 22 had post-LASIK ectasia. Follow-up ranged from 6 months to 17 years.

Dr. Anwar said visual acuity and recovery time following the big bubble procedure were similar to results reported with penetrating keratoplasty.

Postop detachment of Descemet’s membrane occurred in 39 cases, requiring a tamponade with air into the anterior chamber, Dr. Anwar said. None of the patients experienced infection.

Contraindications for the technique include a fragile Descemet’s membrane, macular dystrophy, keratoconus and failure to form the big bubble.

Surgeons should be prepared for a lengthy learning curve when adopting the procedure, he added.