Keratoconus screening in children with Down syndrome

Children with Down syndrome (DS) should be screened for keratoconus, as the incidence is much more common in this cohort, and diagnosis and treatment are often delayed, the Irish College of Ophthalmologists 2023 Annual Conference heard.

Dr Barry Power, Ophthalmic Surgical SpR, Royal Victoria Eye and Ear Hospital (RVEEH), Dublin, gave a short presentation on the potential benefits of screening for keratoconus in children with DS, and reported his own research in the area.

The link between keratoconus and DS is well documented – a Norwegian study estimated the incidence to be 30 times that of the general population. 

However, timely diagnosis and treatment of keratoconus can be more challenging in the DS population, with many of these patients finding invasive treatment very stressful. They also experience poor outcomes, preventable visual loss, and poor quality-of-life due to delayed diagnosis. 

“These children have a much higher risk of development of keratoconus. It seems to happen earlier than the non-DS population, and we know that early intervention is best – surgical rehabilitation in these cases is very, very challenging,” said Dr Power.

To address this issue, Dr Power and colleagues launched a pilot DS keratoconus screening programme in the RVEEH in 2020 in conjunction with the National DS Clinic at Tallaght University Hospital, Dublin.

Children with DS were invited to the cornea clinic in RVEEH for assessment. Medical history, risk factors, BCDVA [best corrected distance visual acuity], and corneal topography were recorded. The data was then compared to a control group of adults with DS who had previously been assessed in the clinic.

The numbers involved in the study were less than hoped for due to the impact of the Covid-19 pandemic, Dr Power noted. A total of 22 children with DS were included in the screening group; complete topographic data was available in 19 patients, with an average age of 13.6 years (range 9-to-18 years). Nine individuals were included in the control group, with topographic data available in eight patients, with an average age of 34.8 years (range 21-to-48 years). 

In the screening group (N=44 eyes), 29 eyes (65 per cent) were kept under review, 10 (22 per cent) were discharged, and five (11 per cent) were treated (all crosslinking). In the control group (N=18 eyes), eight (44 per cent) were kept under review, none were discharged, and 10 (55 per cent) needed treatment. 

This study found steep Ks, high levels of astigmatism and corneal thinning in children with DS, Dr Power reported. The results support the case for screening children with DS for keratoconus, he maintained.

The optimum age to screen has not been established, but based on the pilot study, he said: “We believe the optimum age for this to be the mid-teens, to maximise the ability to undergo topography and to minimise disease progression. Our data shows, unsurprisingly, that younger screened patients have milder disease levels and a lower requirement for intervention than an older, non-screened control group.” 

He recommended using a Pentacam as a screening tool in this cohort, saying it had good tolerability among those who participated in the pilot study.