Viscoat

Iodine (1mg/ml) and oxybuprokain (8mg/ml) were topically administrated to the eye, followed by injection of Viscoat (Alcon, Rødovre, Denmark) to the anterior chambers. A 2-mm in diameter full-thickness corneal perforation was made at the center of the eye of the mini-pig with a trephine. Subsequently, the corneal patch was used to seal the trephined corneal perforation. To patch the perforation, the center of the corneal patch was aligned to the center of the trephined wound to cover the perforation, followed by suturing with 12 nylon sutures (10–0) through the laser-made suture holes on the 12-hole patches. The sutures were made in order of rotational symmetry to keep the seal tight and balanced. After all the sutures were done, cefuroxim (1mg) was administered by intra-cameral injection, and a bandage contact lens was put in place to cover the sutured corneal patch.

A single surgeon (CYP) performed phacoemulsification and intraocular lens (IOL) insertion. Under topical anesthesia, a side-port incision was made with a 1 mm diamond knife; then, the main clear corneal incision was made with a 2.8 mm diamond knife. An ophthalmic viscosurgical device, 4% chondroitin sulfate and 3% sodium hyaluronate (Viscoat, Alcon Laboratories, Fort Worth, TX, USA), was injected into the anterior chamber. Next, a continuous curvilinear capsulorhexis of 5 to 5.5 mm was created with a forcep. After hydrodissection with balanced salt solution, stop and chop phacoemulsification was performed using the Stellaris phacoemulsification machine (Bausch and Lomb, Rochester, NY, USA). An IOL (Tecnis IOL; Abbott Medical Optics, Santa Ana, CA, USA) was implanted within the capsular bag, and residual viscoelastic material was removed from the anterior chamber. After corneal stromal hydration on the main corneal incision with a balanced salt solution, the anterior chamber was reformed using a balanced salt solution. Postoperative medication was the same for all patients and consisted of topical 1% prednisolone and 0.5% levofloxacin 4 times per day for 4 weeks. Prostaglandin analogs were stopped after surgery for 3 months in the glaucoma patients who were treated with prostaglandin analog before surgery.

After local (retrobulbar anesthesia and a Nadbath facial nerve block), a 5.0-mm temporal corneal or corneoscleral incision was made. A 25G anterior chamber maintenance cannula was inserted in one side port. The recipient’s Descemet’s membrane was removed same as DMEK procedure. In most cases, the graft size was 7.75 mm or 8.0 mm. Pre-cut donor grafts were trephinated and the endothelial surface of the lenticle was coated with a small amount of viscoelastic material (Viscoat; Alcon). The donor tissue was gently inserted into the anterior chamber using a Busin glide (Asico) and Shimazaki DSAEK forceps (Inami, Tokyo, Japan). The pull-through technique was used to insert the donor graft. Air was carefully injected into the anterior chamber to unfold the graft. Fifteen minutes after the air injection, most of the air was replaced with balanced salt solution. Intraoperative and postoperative medication was the same as for DMEK.

To measure the ability of SPG-178 to resist the inward diffusion of blood, 2 ml of blood from a rabbit was placed in a 35-mm disposable petri dish after which 0.5 ml of SPG-178 was immersed within it. Photographs were taken immediately and 2 min after placement of the SPG-178, after which the images were digitized using Image J (NIH)²⁰ . The area of blood ingress into the SPG-178 was quantitatively analyzed. The hyaluronic acid gel, Viscoat (Alcon, USA), was similarly tested as a comparator material commonly used in ophthalmic surgery.