Successful use of conjunctival flaps to prolong survival of type I keratoprosthesis in severe bilateral chemical burns: two case reports

Case 1

A 26-year-old male student from the Indian north-east presented with a history of chemical injury with lime in both eyes one year ago. There was no relevant family history. An amniotic membrane grafting (AMG) with symblepharon release was done in both eyes at another hospital. At presentation, visual acuity was hand motions in both eyes. On examination, lid margin in both eyes were thickened with diffuse bulbar conjunctival congestion and 360 degree corneal conjunctivalization. In the right eye, symblephara were present superiorly and temporally. In the left eye, symblepharon were present temporally. A pyogenic granuloma was present at 1 o’clock with a descemetocele in the visual axis in the left eye. The rest of the anterior segment details could not be visualized. Both eyes had some wetness, but the Schirmer’s test was recorded as 5 mm of wetting at 5 minutes. Digital intra-ocular pressure (IOP) and B-scan was normal in both eyes. He was diagnosed with bilateral total LSCD with left eye descemetocele. A type I KPro implantation was planned for the right eye. Because of the severity of the ocular surface damage and the high risk of post-operative surface complications a different approach was taken.

The surgery was done under local anesthesia. Conjunctival peritomy was done superiorly. The conjunctivalized pannus covering the corneal surface was separated from the underlying adhesions by blunt dissection and lifted off the cornea as a single flap with an inferior hinge. Excess fibrovascular proliferation in the undersurface of the reflected flap was excised to make it thin. The host cornea was then trephined with 8.5 mm hand-held trephine and donor cornea with 9.0 mm hand-held trephine. Aurolab keratoprosthesis of +59.0 dioptre was assembled. the graft–host junction was sutured with 16 interrupted sutures with 9-0 nylon. The pannus was replaced back and secured into position with fibrin glue (Tisseel Kit, Baxter AG, Vienna, Austria).

On first post-operative day, mild lid edema was present along with diffuse conjunctival congestion. The anterior surface of the keratoprosthesis was covered by pannus. The patient was started on topical corticosteroid (prednisolone acetate 1%, 6 times per day), antibiotic (moxifloxacin 0.5%, 4 times per day), anti-glaucoma (timolol 0.5%, twice daily) eyedrops along with oral acetazolamide 250mg (once daily at bedtime). An opening in the conjunctival flap, just large enough to expose the underlying optical cylinder, was made 2 weeks later after which the vision improved to 20/50P. The keratoprosthesis was present in place and the ocular surface was stable. Fundus examination was normal. At last follow-up at 82 months, visual acuity in the right eye with −1.25D of spherical correction was 20/20. The ocular surface was stable with conjunctivalized corneal graft and keratoprosthesis in place (Figure 1, 2). Mild posterior capsular opacification was noted. Topical corticosteroids were continued along with topical antibiotic and anti-glaucoma eyedrop.

Figure 1. This is a collage of images of both the patients before and after the surgery.

(A) The right eye of the first patient with total limbal stem cell deficiency with granuloma over the cornea. Superior and inferior symblephara are present. Anterior segment cannot be visualized.

(B) Left eye of the same patient with distichiasis and trichiasis in upper and lower lid. Granuloma is present in the central upper lid. Total limbal stem cell deficiency in present with extensive symblephara. (C) In the right eye, the area of accidental cut supero-nasally was meticulously sutured. The area has healed well with no defect.

(D) Right eye of the first patient, 3 days after the central opening was made. The carrier graft is conjunctivalized. The keratoprosthesis is in place with clear visual axis. The peripheral iridotomy can be seen supero-nasally. (E) The left eye of the second patient. Symblephara are present temporally. Cornea in conjunctivalized completely with a descemetocele in the visual axis. Pyogenic granuloma is present at 1 o clock. The right eye of the patient had similar clinical features on presentation. (F) Right eye of the second patient at 15 months post-surgery. The keratoprosthesis is in place with the carrier graft well conjunctivalized. The ocular surface with healthy with no corneal melt. The visual axis is clear with mild posterior capsular opacification.

Figure 2. Anterior segment optical coherence tomography image at 82 months of follow-up showing a conjunctivalized surface with a stable type 1 keratoprosthesis in place.

Case 2

A 45-year-old male carpenter from north India presented with a history of injury to both eyes with toilet cleaning solution two months ago. There was no relevant family history. He had undergone AMG twice at another hospital. At presentation he had total LSCD with persistent epithelial defects (PED) in both eyes for which AMG with tarsorrhaphy was repeated. Over 3 months, thick fibrotic pannus with granuloma covering cornea and symblepharon was noted in both eyes. Living-related allogeneic simple limbal epithelial transplantation (SLET) was done in the right eye which eventually failed. A Boston type I KPro was done for the left eye which later developed microbial keratitis due to which it had to be explanted.

After 9 months, visual acuity was light perception with accurate projection of rays in both eyes. On slit lamp examination, both eyes had thickened lid margins and distichiasis. Both eyes had thick fibrotic pannus over the cornea, with superior and inferior symblepharon. A granuloma covering the cornea was present in the right eye (Figure 1). Both eyes were relatively wet. B-scan in both eyes had anechoic vitreous. He was planned for a type I aphakic KPro implantation in the right eye. However, with the hindsight of epithelial healing issues and infection in the left eye, and the encouraging outcome seen in the previous case, a decision to use a conjunctival flap was made.

The surgery was done under local anesthesia. The conjunctival flap was raised in a manner similar to the previous case, however there was an inadvertent buttonhole created supero-nasally. Host cornea was trephined with 8.75 mm hand-held trephine and removed. Open sky cataract extraction was performed leaving intact posterior capsule. Two peripheral button iridectomies were done in superior quadrant. Donor cornea was trephined with 9 mm hand-held trephine followed by central 3 mm trephination and Aurokpro was assembled. The graft–host junction was sutured with 16 interrupted sutures with 10-0 nylon. The pannus was replaced in its original position covering the whole ocular surface including KPro and sutured to episcleral tissue with 8-0 vicryl sutures. The inadvertent cut was also sutured meticulously.

On the first post-operative day, topical antibiotic (gatifloxacin 0.5%, 4 times per day) was started along with anti-glaucoma (timolol maleate + brimonidine tartarate, twice per day) eyedrops. Topical corticosteroids (prednisolone acetate 1%, 6 times per day) were started and tapered over 3 weeks to a maintenance dose of 3 times per day. An optical opening was made after 12 days following which the vision was 20/40. After 4 months vision dropped to 20/120. On examination, posterior capsular opacification was noted. On OCT, macular edema was seen. YAG capsulotomy was done along with sub-tenon’s triamcinolone acetanoid injection. At the last follow-up at 24 months, vision was 20/20. On examination, the KPro was noted to be in place and the ocular surface was stable. Resolution of macular edema was seen on OCT. Topical corticosteroid, antibiotic and anti-glaucoma eyedrop were continued.