In patients with corneal melt, pretreatment crosslinking (CXL) of donor tissue prior to placement of Boston keratoprosthesis (K-Pro I) decreases graft failure. We report a case of corneal sparing in a phthisical eye following penetrating keratoplasty (PKP) with pretreatment CXL of the donor cornea.
A 69-year-old female with a history of familial aniridia and bilateral K-Pro I placement. Her clinical course was complicated by recurrent corneal melt and hypotony in the left eye, resulting in extraction of the K-Pro I and successive PKP with pretreatment CXL of the donor cornea. She subsequently developed phthisis of the globe with notable retention of corneal structure. At 8 years, she maintains corneal contour without recurrence of keratolysis or extension of phthisis.
Conclusions and importance
This is the first reported case of corneal sparing in a phthisical eye with a history of PKP, suggesting a protective role of pretreatment CXL of donor tissue against keratolysis and phthisis.
Phthisis bulbi is a rare condition that results in disorganized and shrunken ocular structures. The pathogenesis involves disorganization, calcification, and ossification of tissue secondary to prior insult. The pathologic causes are broad and include trauma, hypotony, and inflammation. Both anterior and posterior structures are frequently involved, including a thickened and disorganized corneal structure.
There are reports on the use of crosslinked carrier tissue in patients with severe keratolysis prior to the placement of Boston keratoprosthesis. , To our knowledge, no study has reported the potential protective role of corneal crosslinking in maintaining corneal architecture in the context of phthisis. We describe a case of phthisis with corneal sparing in the setting of pretreatment collagen crosslinking of the donor tissue during a penetrating keratoplasty.
A 69-year-old female with familial aniridia complicated by corneal blindness initially underwent traditional bilateral Boston keratoprosthesis (K-Pro) placement, first in the right eye in June 2008, followed by a 9.5 mm K-Pro with a titanium backplate in the left eye in October 2009. The post-operative period in the left eye was complicated by persistent post-operative sterile vitritis that cleared over the course of one year.
Two years later, the left eye developed Hand Motion vision. Exam was notable for a hypotonus eye with keratolysis under the front plate as well as Seidel positive leakage of the aqueous humor. The patient was brought to the operating room for replacement of the K-Pro with a new corneal donor carrier. During the procedure, the retroprosthetic membrane was noted to be adhered to the K-Pro backplate and the intraocular lens. Both were excised and removed from the eye. An anterior vitrectomy was performed and a new aphakic K-Pro was inserted.
Three months later, the patient presented following a gush of fluid form the left eye. Hypotony was again noted in the left eye, which had an irregular globe contour. SD-OCT showed choroidal thickening and retinal elevation.
Given that the patient had recurrent keratolysis in the left eye, the surgical team discussed collagen crosslinking the donor tissue prior to implantation to strengthen the tissue and help prevent keratolysis as part of an investigator-initiated study (NCT02863809). The next day the patient was brought to the OR for combined K-Pro replacement using the crosslinked corneal donor tissue and pars plana vitrectomy with membrane peel and silicone oil placement. Within the operating room prior to the surgery, the donor corneal tissue was placed on an anterior chamber maintainer and crosslinked using the Dresdon Protocol. During surgery, the patient was found to have a large funnel retinal detachment that was not amenable to surgical repair. Given the limited visual potential for the eye, the decision was made to place the crosslinked corneal graft without the K-Pro.
The vision during the immediate post-operative period was Light Perception and the eye remained soft, with an intraocular pressure of 4 mmHg. The slit lamp examination was notable for a diffusely thickened penetrating keratoplasty graft with Descemet membrane folds. The graft was Seidel negative with silicone oil observed against the posterior surface of the graft. In January 2012, phthisical changes were first noted in the conjunctiva of the left eye. However, there were no phthisical changes in the cornea ( Fig. 1 ).