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Pachymetry-Guided Intrastromal Air Injection (“Pachy-Bubble”) for Deep Anterior Lamellar Keratoplasty

Ghanem, Ramon C. MD, PhD; Ghanem, Marcielle A. MD

doi: 10.1097/ICO.0b013e31823f8f2d

To evaluate an innovative technique for intrastromal air injection to achieve deep anterior lamellar keratoplasty (DALK) with bare Descemet membrane (DM). Thirty-four eyes with anterior corneal pathology, including 27 with keratoconus, underwent DALK. After 400 μm trephination with a suction trephine, ultrasound pachymetry was performed 0.8 mm internally from the trephination groove in the 11 to 1 o'clock position. In this area, a 2-mm incision was created, parallel to the groove, with a micrometer diamond knife calibrated to 90% depth of the thinnest measurement. A cannula was inserted through the incision and 0.5 mL of air was injected to dissect the DM from the stroma. After peripheral paracentesis, anterior keratectomy was carried out to bare the DM. A 0.25-mm oversized graft was sutured in place. Overall, 94.1% of eyes achieved DALK. Bare DM was achieved in 30 eyes, and a pre-DM dissection was performed in 2 eyes. Air injection was successful in detaching the DM (achieving the big bubble) in 88.2% of the eyes. In keratoconus eyes, the rate was 88.9%. All cases but one required a single air injection to achieve DM detachment. Microperforations occurred in 5 cases: 3 during manual layer-by-layer dissection after air injection failed to detach the DM, 1 during removal of the residual stroma after big-bubble formation, and 1 during the diamond knife incision. Two cases (5.9%) were converted to penetrating keratoplasty because of macroperforations. The technique was reproducible, safe, and highly effective in promoting DALK with bare DM.

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*Department of Cornea and Refractive Surgery, Sadalla Amin Ghanem Eye Hospital, Joinville, Santa Catarina, Brazil

Department of Ophthalmology, University of São Paulo, São Paulo, Brazil.

Reprint: Ramon C. Ghanem, Sadalla Amin Ghanem Eye Hospital, Rua Abdon Batista 172, Joinville, SC 89201-010, Brazil (e-mail:

The authors have no financial or proprietary interest in any material or method mentioned in the article.

Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Web site (

Received May 4, 2011

Accepted August 24, 2011

Copyright © 2012 Wolters Kluwer Health, Inc. All rights reserved.