ABSTRACT

A 61-year-old man presented with corneal perforation of 1.0 mm in diameter in his right eye caused by a metallic foreign body fragment. We used the “one-bite mini-keratoplasty” technique, which uses a cornea patch with a single host-graft-host suture to stop aqueous humor leakage. Postoperatively, the graft was completely epithelialized. The suture was removed and the use of soft contact lens was discontinued. Postoperative best-corrected visual acuity (BCVA) recovered to 180/200 and corneal astigmatism was 0.6 diopters. The postoperative course was unremarkable, but corneal perforation recurred due to an ocular contusion at 17 months. He was reoperated using the same technique. His BCVA was 160/200 and corneal astigmatism was 1.1 diopters after reoperation. Despite performing this surgical technique twice for corneal perforation, optimal visual function was maintained even after 2 years. For paracentral corneal perforations, our simple technique may reduce astigmatism and maintain high visual function.

Introduction

Corneal perforation is an emergency condition that may occur due to eye trauma or infectious corneal disorders and leads to hypotony. Although it is necessary to close the perforation, strong astigmatism is likely to occur with simple sutures and conventional lamellar keratoplasty for paracentral corneal perforation. To improve visual acuity and prevent corneal irregular astigmatism as much as possible, we performed “one-bite mini-keratoplasty,” in which insertion of a very small corneal graft into the paracentral corneal perforation was achieved using a single suture to the host cornea. Using this new approach, we successfully treated the patient’s corneal perforation and also minimized astigmatism.

Discussion

Use of SCL is an effective approach to suppress aqueous humor leakage occurring as a consequence of corneal perforation.¹ However, large corneal perforations cannot be prevented using SCL; furthermore, simple suturing causes visual function deterioration due to strong corneal irregular astigmatism. Amniotic ² and fibrin glue-assisted amniotic membrane transplant methods ^3,4 have been reported to alleviate corneal astigmatism, but these procedures are more complex than our technique. Lamellar keratoplasty is another procedure that is effective against perforation.⁵ However, this procedure is associated with a possibility of negatively affecting visual function when using a graft larger than the perforated area in cases where the perforation is near the center of the cornea. We performed one-bite mini-keratoplasty in a patient in whom aqueous humor leakage could not be stopped using an SCL. Because the diameter of the corneal defect was 1.0 mm, we initially considered conventional lamellar keratoplasty; however, due to the difficulty of applying several sutures radially around the graft, we adopted the single-suture method using as a filler a corneal graft of approximately the same size as that of the corneal defect. Previous studies have reported the use of “small-diameter keratoplasty”^6,7 or “small-diameter graft,”^7,8 but the use of a small-diameter graft approximately 1.0 mm in size or a suturing method with a single suture has not been previously reported. Chern et al.⁶ reported severe irregular astigmatism after a “small-diameter, eccentric penetrating keratoplasty” was performed for paracentral corneal perforation. In our patient, the first surgery using this technique showed successful results with little astigmatism. Also, we observed corneal astigmatism of 1.1 diopters and BCVA of 160/200 despite the paracentral corneal re-perforation secondary to ocular trauma that occurred after performing one-bite mini-keratoplasty.

Corneal tissue is sturdier than amniotic material, and suturing tangentially to the cornea can help minimize corneal astigmatism. In addition, because corneal grafts can be secured without gaps, our technique enables plugging the aqueous humor leakage more reliably than using an amniotic membrane. The corneal tissue provides a scaffold for promoting corneal epithelialization in addition to filling the defect site. In this case, the graft epithelialized and remained stable over the long term. Therefore, in our patient, one-bite mini-keratoplasty resulted in the maintenance of high visual function by suppressing aqueous humor leakage, helping attain corneal epithelialization, and maintaining good visual acuity. This technique is useful in settings where donor cornea is available. Therefore, one-bite mini-keratoplasty could help preserve long-term corneal stability and good visual function including minimize corneal astigmatism for the treatment of paracentral corneal perforation.