High-resolution optical coherence tomography-guided donor tissue preparation for descemet membrane endothelial keratoplasty using the reverse big bubble technique.

The aim of this study was to assess the feasibility of high-resolution spectral domain optical coherence tomography (HR-SDOCT) to guide donor tissue preparation in Descemet membrane endothelial keratoplasty using the reverse big bubble technique. Three corneoscleral discs were included in this ex vivo experimental study. A 27-G cannula was introduced into each cornea at the periphery by 3 different surgeons. Each surgeon attempted to achieve the ideal depth (pre-Descemetic plane) of the tip of the cannula for air injection to produce the reverse big bubble to separate the Descemet membrane (DM) from the posterior stroma. A supine optical coherence tomography system built at the Ophthalmic Biophysics Center of the Bascom Palmer Eye Institute was used to estimate in real-time the depth reached by the tip of the cannula in the posterior stroma during tissue preparation. After air injection, 1 successful big bubble was obtained, while each of the other corneoscleral discs had intrastromal emphysema and DM perforation. On HR-SDOCT evaluations, artifacts were noticed at the tip of the cannula. The successful big bubble demonstrated the separation of the DM and the stroma without intrastromal hyperreflectivity. Emphysema was visualized on the HR-SDOCT as a hyperdense intrastromal area shadowing the posterior structures of the anterior chamber. The HR-SDOCT-guided reverse big bubble technique may be a useful method to prepare donor tissue in Descemet membrane endothelial keratoplasty. Further improvements in high-resolution optical coherence tomography technology are needed this promising technique

Factors affecting DSAEK graft lenticle adhesion: an in vitro experimental study.

The aim of this study was to evaluate different factors that affect Descemet stripping automated endothelial keratoplasty (DSAEK) donor graft lenticle adhesion to the recipient cornea. This experimental study included 10 eye bank recipient corneas and 10 donor DSAEK lenticles. Recipient corneas were mounted on an artificial anterior chamber (AC), whereas donor lenticles were placed beneath the host cornea. Using optical coherence tomography and imaging software, the interface gap (IG) between the donor and recipient cornea was quantified to evaluate the effect of variations in AC air fill pressure, AC air fill duration, corneal massage, and corneal venting incisions on DSAEK donor graft lenticle adhesion. Different intraocular pressures (IOP) under air for the same time intervals, do not significantly correlate with the IG; nevertheless, it was noticed that the IG decreases as the IOP increases. With respect to the magnitude of AC IOP, there was no statistically significant difference when comparing 10 mm Hg with 30 mm Hg and assessing IG (P = 0.4). Complete air-fluid exchange resulted in significantly higher IG when compared with AC air bubble of 10 and 30 mm Hg that was sustained for 1 hour (P < 0.05). Furthermore, corneal surface massage did not facilitate DSAEK graft adhesion (P = 0.59). Finally, paracentral venting incisions followed by interface fluid aspiration seemed to significantly decrease the IG (P = 0.014). Corneal venting incisions and higher AC IOP values seem to facilitate DSAEK donor graft lenticle adhesion to the recipient cornea

Acanthamoeba Keratitis: Current Status and Urgent Research Priorities

Background: First discovered in the early 1970s, Acanthamoeba keratitis has remained a major eye infection and presents a significant threat to the public health, especially in developing countries. The aim is to present a timely review of our current understanding of the advances made in this field in a comprehensible manner and includes novel concepts and provides clear directions for immediate research priorities.Methods: We undertook a search of bibliographic databases for peer-reviewed research literature and also summarized our published results in this field.Results: The present review focuses on novel diagnostic and therapeutic strategies in details which can provide access to management and treatment of Acanthamoeba keratitis. This coupled with the recently available genome sequence information together with high throughput genomics technology and innovative approaches should stimulate interest in the rational design of preventative and therapeutic measures. Current treatment of Acanthamoeba keratitis is problematic and often leads to infection recurrence. Better understanding of diagnosis, pathogenesis, pathophysiology and therapeutic regimens, would lead to novel strategies in treatment and prophylaxis