Fungal infection after endothelial keratoplasty: association with hypothermic corneal storage

PurposeTo compare the incidence of fungal infection after endothelial keratoplasty (EK) when donor tissue had been stored in hypothermic medium or organ culture.MethodsWe describe the clinical features of 10 cases of fungal infection (keratitis or endophthalmitis) following EK identified at three European centres. Case definition was the culture of fungus or a positive PCR from the host cornea or anterior chamber after EK. A survey of the incidence of infection after EK was conducted by the European Eye Bank Association. The main outcome measure was the number of cases in which donor tissue had been stored in hypothermic medium compared with organ culture.ResultsThe 10 cases occurred between 2014 and 2017. All donor corneas had been stored in hypothermic medium sourced from three US eye banks. Three pairs of mate corneas caused infections in six recipients. Candida spp were identified from nine cases, with one isolate of Purpureocillium lilacinum. Data on 16 862 corneas supplied for EK were available from 16 European eye banks for the 5-year period from 2012. There were 17 reported cases of infection, of which 15 (88%) were fungal infections and 14 (82%) were Candida spp. Fungal infection was reported from 3 of 14 476 (0.02%) corneas supplied in organ culture compared with 12 of 2386 (0.50%) corneas supplied in hypothermic medium (p<0.0001). The incidence of infection after hypothermic storage was similar for material sourced from Europe (0.52%) or the USA (0.61%).ConclusionsInfection after EK is strongly associated with Candida spp. The possible explanations for the higher incidence of infection when tissue is stored in hypothermic medium are discussed.

Limbal Stem Cell-Sparing Corneoscleroplasty with Peripheral Intralamellar Tuck: A New Surgical Technique for Keratoglobus

Purpose: To describe the technique of limbal stem cell-sparing corneoscleroplasty for the management of advanced keratoglobus. Methods: A patient with bilateral advanced keratoglobus, with best-corrected visual acuity of 20/400 in the right eye and 20/200 in the left eye, underwent limbal stem cell-sparing corneoscleroplasty of the right eye. Initially, a 360-degree limbal incision with 200-μm depth was created, followed by a sublimbal tunnel dissection into the sclera, in order to conserve stem cells. Next, a limbus-to-limbus lamellar keratectomy at 200-μm depth was performed. Meanwhile, a donor corneoscleral button with preserved endothelium of the central 8 mm was fashioned. Prior to suturing the donor corneoscleral graft using a modified suturing technique to cover its scleral component, a full-thickness trephination of 8-mm diameter was completed in the central host cornea. Results: Reepithelialization occurred within the first week. No episodes of rejection, intraocular pressure spikes, or epithelial breakdown were observed postoperatively. At the 6-month follow-up, the patient had 20/70 best-corrected vision and a smooth cornea with regular astigmatism on topography. Conclusion: Limbal stem cell-sparing corneoscleroplasty is a single-step technique for restoring the structural integrity of the cornea in advanced keratoglobus while preserving the host limbal stem cells.

Efficacy of Intraoperative Anterior Segment Optical Coherence Tomography during Descemet's Stripping Automated Endothelial Keratoplasty

Purpose. To examine the graft-host interface during Descemet's stripping automated endothelial keratoplasty (DSAEK) surgery with optical coherence tomography (OCT). Design. Prospective, interventional case series. Patients and Methods. Eight patients who underwent a DSAEK were included. A handheld OCT was used intraoperatively to examine the presence of interface fluid between the host cornea and the graft. Results. In 3 patients, no interface fluid was detected between the host cornea and the graft after the graft was attached by air injection. In 4 patients, interface fluid was detected after the graft was attached by air injection. The remaining interface fluid was drained through corneal stab incisions. One patient required a second surgery because the first surgery failed due to persistence of the interface fluid. All patients showed a complete attachment of the graft at one month after the DSAEK surgery. Conclusion. A handheld OCT is useful to detect the interface fluid between the host cornea and the graft during a DSAEK.

PVA-HAp Nanocomposites for Artificial Cornea

To solve the shortage of the donor cornea in Japan, we are developing a poly(vinyl alcohol) hydrogel based keratoprosthesis. Minimum requirements for a keratoprosthesis include light transparency, non-toxicity, and nutrition and fluid permeability. Earlier clinical trials had frequently failed because corneal epithelial down growth occurred between the host cornea and the materials, and the materials were finally rejected from the host cornea. The major cause of this rejection is the weak adhesion between the host cornea and the prosthesis. In order to achieve the firm fixation of the artificial cornea to host cornea, composites of collagen-immobilized poly(vinyl alcohol) hydrogel with hydroxyapatite(PVA-HAp nano composites) were synthesized. The preparation method, characterization, and the results of corneal cell adhesion and proliferation on the composite materials were studied. The PVA-HAp nano composites were successfully synthesized. Chick embryonic keratocyto-like cells were well attached and proliferated on the PVA-HAp composites. This material showed potential for keratoprosthesis.