ALTERNATIVE STRATEGIES

An eye with a well recognised corneal pathology can still require careful weighing up of options, said José L Güell MD, Autonomous University of Barcelona, Spain, at the 18th ESCRS Winter Meeting’s Cornea Day in Ljubljana, Slovenia. He presented a case-report involving a 69-year-old who developed a Pseudomonas corneal abscess with significant anterior chamber reaction in his left eye after traumatic corneal erosion in May 2013. The patient's diseased eye had poor light perception and significant cortical cataract. The IOP was 14.0 mmHg and the B-scan was normal.

Dr Güell said the patient was not in pain and it was not clear how much vision could be salvaged. He asked the audience which course they would have advised. One attendee suggested that because OCT showed a very deep scar, a lamellar keratoplasty would be indicated. Rudy Nuijts MD cautioned that more extensive investigation might be warranted. He added that he would recommend testing the corneal sensitivity at 12 o'clock and PCR-testing for possible herpes infection and an anterior chamber tap to determine if there was an intraocular infection. He noted that an active infection of any type could have a negative impact on the success of a corneal graft.

Preoperative image and six months postoperative
Courtesy of Jose L Güell MD

CORNEAL SENSITIVITY
Dr Güell responded that they had tested corneal sensitivity and found it normal, but they did not perform PCR because it had all the signs of a post -traumatic microbial silent infection. They ultimately decided to perform deep anterior lamellar keratoplasty, cataract extraction and IOL implantation in the same procedure. The plan was to visualise the cataract surgery through a thin layer of viscoelastic placed on top of the denuded Descemet’s membrane prior to placement of the corneal button.

However, the scar tissue penetrated much deeper into the cornea than the initial 200 micron trephination and during the scraping of the residual stroma some liquid leaked out, indicating a gap in Descemet’s membrane and the endothelium.

CATARACT PROCEDURE
Dr Güell therefore converted the procedure to a penetrating keratoplasty. He implanted an Ekhardt temporary prosthesis to prevent expulsive haemorrhage while he performed the cataract procedure. To widen the pupil, he first used adrenaline injections and mechanical and viscostretching manoeuvres. When these failed he used iris retractors. Upon completing the surgery, he sutured the donor cornea button in place and injected bevacizumab intrastromally in those areas with significant reactive neovascularisation. At three weeks' follow-up the cornea was clear and there was no significant corneal oedema.

However, visual acuity was unexpectedly low at 0.05. OCT revealed the presence of cystoid macular oedema. Dr Güell noted that CME is the most common cause of low vision after any type of keratoplasty procedure, especially when combined with another intraocular procedure.

To treat the condition, he adopted a staged protocol, first adding topical NSAIDs to the topical steroids regimen. When that failed, he added oral acetazolamide but the oedema still proved resistant. He therefore injected triamcinolone intravitreally and three weeks later the patient’s decimal visual acuity was 0.7 despite a diffuse temporary epitheliopathy. "This case shows that even in a standard normal case there are a lot of things to discuss,” Dr Güell concluded.