Mk 2000

A corneal flap was prepared using a microkeratome with a custom-made hand piece for a rabbit cornea (MK-2000; Nidek Co., Ltd., Tokyo, Japan). A circular central wound of 4 mm in diameter and 200 μm in depth was prepared using a biopsy trephine (Kai Industries, Co., Ltd., Gifu, Japan) and surgical knife. Decellularized corneas with thicknesses of 160 μm were trephined using biopsy punches of 4 mm in diameter. Then, the decellularized cornea was placed on the corneal wound and covered with a corneal flap. To prevent the slippage of the transplanted decellularized cornea, a contact lens made from polyvinyl alcohol (PVA) was placed in the operated eye and the eyelid was sutured using 3-0 nylon sutures. Topical 0.5% levofloxacin hydrate (Cravit; Daiichi Sankyo Co., Ltd., Tokyo, Japan) was administered until the first week of surgery. Sutures were cut at 1 week after surgery. After 6 months, the rabbits were sacrificed with sodium pentobarbital and corneas, including the transplanted decellularized corneas, were removed. The tissues were evaluated by light microscopy and TEM using the same procedures described above.

In the LASIK procedure, a microkeratome (MK-2000; Nidek, Aichi, Japan) with a 160-μm head was used to create an 8.5-mm corneal flap with a nasal hinge. Laser ablation was performed with a VISX Star S2 or Star S4 excimer laser (AMO, Santa Ana, CA, USA). In all procedures, a 6.0-mm optical zone and conventional ablation were used. After surgery, 0.1% fluorometholone and 0.5% levofloxacin eye drops were prescribed four times daily, starting the day after surgery, for 2 weeks, three times daily for 2 weeks, and then twice daily for 1 month.
In the PRK procedure, the central 6.0-mm diameter epithelium was ablated with an excimer laser. Laser ablation was performed with a VISX Star S or Star S2 excimer laser (AMO). After PRK laser treatment, a bandage soft contact lens was placed on the cornea. Eye drops containing 0.1% betamethasone sodium phosphate (Shionogi Pharmaceutical, Osaka, Japan) and 0.5% levofloxacin (Santen Pharmaceutical, Osaka, Japan) were prescribed four times daily starting the day after surgery for 2 weeks, After 2 weeks, the 0.1% betamethasone sodium phosphate eye drops were terminated, and 0.1% fluorometholone eye drops (Santen Pharmaceutical) were prescribed four times daily for 3 months, three times daily for 2 months, and then twice daily for 2 months.