The importance of 'Ret'

It may be a dying art, but retinoscopy has at least one thing going for it that autorefraction does not – as an early warning sign of keratoconus in children with Down’s syndrome.

Cardiff University senior lecturer, Dr Maggie Woodhouse, cautioned the audience at the Hospital Optometrists Annual Conference (7–9 October, Stratford upon Avon) that: “A lot of optometrists in practice have abandoned retinoscopy in favour of autorefraction. We’re losing a valuable skill.”

After studying the development of keratoconus in children with the genetic condition caused by the presence of an extra chromosome, Dr Woodhouse and her PhD student, Stephanie Campbell, reinforced the unique role that retinoscopy plays in the eye examination.

They tracked 45 young patients with Down’s syndrome, many from a Cardiff University group who joined as babies. Others from across the UK with both Down’s syndrome and keratoconus participated.  Eleven participants had keratoconus, and the remainder were demonstrated to have healthy corneas.

Of the assessed optometric diagnostics from slit lamp signs to astigmatism, only retinoscopy identified the young patients with Down’s syndrome in the early stages of keratoconus as confirmed by a Pentacam, Dr Woodhouse outlined.

The early diagnosis of keratoconus is crucial for patients with Down’s syndrome, Dr Woodhouse stressed. Ophthalmic guidelines require a corneal thickness of 400 microns to perform corneal crosslinking, and people with Down’s syndrome have a corneal thickness of just 480 microns, on average, she told the conference audience.

“Therefore, if a patient’s cornea is thinning, we’ve got a very short time window to diagnose and initiate treatment before it’s too late,” Dr Woodhouse emphasised.

While the research numbers were small and the results needed to be validated in a larger study, Dr Woodhouse was confident that Ret was a skill too important to be lost.

“If an optometrist doesn’t use retinoscopy then, in my opinion, they shouldn’t be seeing children with learning disabilities,” she said.

A specialised screening service with optometrists accredited with the training and skills – such as retinoscopy – needed to perform eye examinations on children with special needs may be a possible solution, she told attendees.

While the higher prevalence of keratoconus in patients with Down’s syndrome was well known, the reason behind this was not. The study found no evidence to suggest eye rubbing was a factor, Dr Woodhouse highlighted.

Her team believes a defect in the collagen proteins of these patients may be to blame, and will be examining this hypothesis in more detail in future, delegates were told.

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