Results of viscobubble deep anterior lamellar keratoplasty after failure of pneumatic dissection

Abstract

Intrastromal injection of OVD after failed pneumatic dissection increases considerably the success rate of bubble formation (from 75.71% to 95.71% in our series); however, when bubble formation fails, infiltration of OVD into the residual stroma makes manual dissection particularly challenging and causes severe interface haze resulting in poor visual outcomes.

Predictors of Bubble Formation and Type Obtained With Pneumatic Dissection During Deep Anterior Lamellar Keratoplasty in Keratoconus

“…[20][21][22][23] Conversely, eyes with milder stages of keratoconus, where the failure of pneumatic dissection was higher, might benefit from OVD injection through the same track that was used unsuccessfully for air injection bubble. 19,24 Several parameters including age, K-mean, thinnest point and AS-OCT staging differed significantly between cases in which type-1 bubble occurred compared to type-2 bubbles. In particular, milder stages of KC (higher pachymetric values, lower K-mean, and early AS-OCT stages from 1 to 3 a) in addition to younger age were associated with type-1 bubble formation.…”

“…When pneumatic dissection failed, the procedure was continued, attempting injecting ophthalmic viscoelastic device (VI-VACY sodium hyaluronate 1.55%, I-SPACE Laboratoires, La Ravoire, France) through a cannula inserted into the same stromal path used for pneumatic dissection, according to the surgical steps previously described. 19 If also OVD-assisted dissection failed, layer-by-layer manual dissection was performed aiming at reaching a level in the deep stroma free from all micro-bubbles. The donor cornea was punched from the endothelial side with a Barron donor punch (Katena Products, Inc.) of the same diameter of the trephine used on the recipient cornea.…”

Predictive Factors for Successful Type 1 Big Bubble during Deep Anterior Lamellar Keratoplasty

“…On the other hand, in keratoconus with deep posterior scars, it probably would be wiser to perform manual dissection assisted by peroperative OCT, rather than taking the risk of perforation with the big bubble technique. Other dissection techniques such as Melles' method, manual dissection, hydrodissection, and viscodissection could be intended [ 37 – 39 ].…”

Deep Anterior Lamellar Keratoplasty: Current Status and Future Directions

“…37 Because manual dissection is particularly tedious and is a significant risk factor for conversion to PK, we prefer sequential viscoelastic-assisted dissection in cases of failed pneumatic dissection and consider manual dissection only when all else fails. 4,38 Even in cases of failed pneumatic dissection, the success of viscobubble formation approaches 90% (see Supplemental Video 2, Supplemental Digital Content 2, http://links.lww.com/ICO/B262). 38 Although retained viscoelastic is initially associated with visually significant interface haze, the effect on visual acuity is transient and final outcomes are comparable with those of big-bubble DALK (Fig.…”

“…4,38 Even in cases of failed pneumatic dissection, the success of viscobubble formation approaches 90% (see Supplemental Video 2, Supplemental Digital Content 2, http://links.lww.com/ICO/B262). 38 Although retained viscoelastic is initially associated with visually significant interface haze, the effect on visual acuity is transient and final outcomes are comparable with those of big-bubble DALK (Fig. 1).…”