Background

Chemical ocular burns may be caused by various agents such as acids, alkalis, organic substances, urea, etc.1 Alkali substances, being lipophilic, penetrate into the eye more rapidly than acids, causing severe corneal damage along with limbal stem cell deficiency (LSCD) and, rarely, on entry into the anterior chamber, result in cataract formation.2 In such instances, only performing limbal stem cell transplantation may help to epithelialise and clear the cornea, but the eye may still have defective vision owing to the impending cataract. Simple limbal epithelial transplantation (SLET) is a novel simplified surgical technique for treating unilateral LSCD following ocular burns, requires less donor tissue and eliminates the need for a sophisticated stem cell laboratory.3 The outcome of cataract extraction following SLET has not been reported previously. This case describes the outcome of cataract surgery after stabilising the ocular surface by performing SLET.

Case presentation

A 19-year-old woman was referred to our tertiary eye care centre from a local referral facility, with a diagnosis of total right eye LSCD associated with mechanical ptosis following accidental injury caused by lime particles when she was 6 years of age. On examination, the left eye was found to be normal with a best-corrected visual acuity (BCVA) of 20/20. The BCVA in the right eye at the time of presentation was light perception with accurate projection of rays, and the intraocular pressure was digitally normal. External examination revealed minimal motility restriction on elevation, and depression and adduction. Slit-lamp examination showed a vascularised corneal scar with superior and inferior symblepharon (video 1). The rest of the anterior segment examination was unremarkable.

Investigations

There was no view of the intraocular structures in the right eye owing to the ocular surface pathology, so an ultrasound B scan was performed. The scan revealed the eye to be phakic, with a normal posterior segment.

Differential diagnosis

A diagnosis of total unilateral LSCD following lime injury was made for the right eye after reviewing the complete history and clinical features. Other possible causes such as early ulceration or peripheral infectious keratitis, pterygium and ocular surface squamous neoplasia seemed unlikely in view of the clear history of lime injury.

Treatment

The patient was informed about the need to harvest tissue from the limbus and conjunctiva of the left eye, and the procedure of generating and transplanting cultured epithelium to reconstruct the surface of the right eye was described. In addition, limited visual prognosis due to a possible chance of amblyopia was also mentioned. However, the patient was lost to follow-up after the initial visit.

Two years later, the patient reported to us again, willing to undergo surgery as earlier advised. She underwent left eye limbal biopsy excision at the 1 o’clock position. The cultured limbal epithelium was then, 2 weeks later, transplanted into the right eye. Postoperatively, steroid eye drops in tapering doses and antibiotic drops were prescribed in both the eyes.

Outcome and follow-up

On postoperative examination, the limbal biopsy site was found to be healthy in the left eye. In the right eye, the amniotic membrane graft with the limbal explants was found to be in place, sealed with fibrin glue and bandage contact lens. At 2 months follow-up, the unaided visual acuity in the right eye was counting fingers at 50 cm. On examination, there was a residual superior symblepharon and the lens was cataractous. The outcome of cultivated limbal epithelial transplantation (CLET) was good. Hence, only symblepharon release with conjunctival autograft was planned. It was performed 6 months later at the patient’s convenience. Two months following this procedure, the patient had reported pain and a foreign body sensation in the right eye. Her visual acuity was hand movements and slit-lamp examination revealed a superior conjunctival granuloma. No intervention was planned and the patient was prescribed tapering doses of topical steroid and topical lubricant.

Eight months later, with persisting visual acuity of hand movements and a conjunctival nodule along with superior symblepharon in the right eye, an impression of failed CLET was made. Accordingly, a symblepharon release with conjunctival autograft and SLET was performed in the right eye, using one-clock hour of donor limbal tissue from the left eye. At 2-month review, the visual acuity in the right eye improved to 20/400. The ocular surface was stable. However, the visual acuity dropped to 20/500 in a subsequent visit after 7 months and a complete evaluation revealed recurrence of LSCD by around 180°, excluding the visual axis and cataract in both eyes (right more than left). The posterior segment of the right eye was found to be within normal limits on ultrasound biomicroscopy. Consequently, cataract extraction with posterior chamber intraocular lens (IOL) implantation was performed in the right eye. To obtain keratometry (K) for IOL calculation, the K readings were measured using A-scan ultrasound biometry (right eye: K1=42.40 and K2=46.11; left eye: K1=41.14 and K2=42.37). The difference in K readings of the right eye was large because of the surface irregularity due to a vascularised corneal scar. Repeat measurements gave similar results. One week postoperatively, the visual acuity in the right eye improved to 20/60 and the ocular surface was stable. The patient was prescribed tapering doses of topical steroid and a topical lubricant. During a follow-up visit at 5 months (figure 1A–C), the patient continued to maintain a stable unaided visual acuity of 20/60, with planorefraction. Since a PROSE (Prosthetic Replacement of Ocular Surface Ecosystem) lens improved the visual acuity only slightly (to 20/50), it was not prescribed. The patient was advised follow-up every 6 months.

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Figure 1

(A) Slit-lamp photograph of the right eye post simple limbal epithelial transplantation at 5-month follow-up after cataract extraction showing complete epithelialisation of the surface with improved corneal clarity. (B) Enlarged view of (A). (C) Slit view of (A).