Visual rehabilitation

PK alternatives

Classifying opacities can help guide choices. Dermot McGrath reports

Surgeons should remain open to the possibility of trying alternative techniques to penetrating keratoplasty for select cases of congenital corneal opacities in paediatric patients, according to Ken Nischal MD, FRCOphth.

“Our goal should not necessarily be to perform a penetrating keratoplasty at all costs. Rather we should focus on the goals of visual rehabilitation and developmental vision, which is more important the younger the child is. We also want to achieve a clear visual axis, which does not necessarily have to be perfectly centred as children can use eccentric fixation very well,” he said at the World Ophthalmology Congress 2020 Virtual.

Dr Nischal, Professor of Ophthalmology at the University of Pittsburgh School of Medicine, noted that the possible alternatives to PK such as iridectomy and selective endothelial removal depend on a number of factors including the location of the opacity, the state of the endothelium, the social circumstances of the child, the state of the limbal stem cells and the condition of the ocular surface, in particular the lids.

Classifying opacities in terms of primary and secondary corneal disease is a helpful approach in trying to determine the best option for a particular case, he said.

“Indications such as corneal dystrophies, corneal structural deficits due to dermoids and rarer conditions such as CYP1B1 cytopathy tend to do well with transplants, as do iridocorneal adhesions only. However, development anomalies of the anterior segment where the lens fails to form or where the lens fails to separate from the cornea, or where the lens separates but fails to form thereafter, are possible candidates for some of the alternative procedures,” he said.

Dr Nischal cited the example of a paediatric patient with keratolenticular adhesion who obtained a good outcome without resorting to full-blown keratoplasty.

“The technique I used was enter the capsular bag, evacuate the lens and then cut the stalk of the lens to the cornea without tearing it off the endothelium. I was able to do optic capture on the posterior capsule and increase the area of the pupil. The child achieved a good red reflex in both eyes and developmental vision without the need for a corneal transplant,” he said.

A case report by Jodhbir Mehta et al in Singapore has also shown the use of selective endothelial removal in a patient in which a central opacity was present, and a posterior stroma was missing, said Dr Nischal.

“It was interesting in that the endothelium around the diseased area seemed to grow in once the tissue was removed, and in select cases you actually get clearing of the cornea. It underlines the point that while corneal transplantation is very important, it is not always the only or best option for every case,” he concluded.

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