Orthoptist vs optometrist: a child's squint, and how fast to refer

In Scotland, orthoptists screen the vision of children aged 3.5 to 5.5, and the screening looks for more than blur. A study in Ophthalmic and Physiological Optics, published online in March, analysed five years of that screening from eight health boards. Squint, intermittent included, was found in 1.42% of children screened in 2013–14 and 2.19% in 2021–22, and binocular vision anomalies as the study defined them rose from 3.02% to 4.89%.

For a UK optometrist that turns orthoptist vs optometrist into a practical question. A child with a turn in the eye can reach either profession first, and the referral rules decide where the child goes next and how fast.

What the study did

Since 2013, See4School has invited every child in Scotland registered with a GP, and not already under the hospital eye service, to screening by an orthoptist. Evans and colleagues used the eight health boards that returned data every year, which cover over 85% of Scotland's population, for 2013–14 to 2015–16 and 2020–21 to 2021–22: between 35,643 and 42,431 children a year. Each child had a cover test at distance and near and an eye movement check. Its binocular vision anomalies include strabismus, esophoria, some exophoria and eye movement problems. These are screening results, not diagnoses.

What was found

It rose every year studied, 3.02%, 3.78%, 3.83%, 4.87% and 4.89%, but most of the rise fell across the four years with no data. Two things drove it. Squint rose from 1.42% to 2.19%, mostly intermittent exotropia, which more than doubled from 0.43% to 0.98%, while esotropia stayed near 1% (0.88% in 2013–14, 1.05% in 2021–22). And esophoria doubled, from 1.06% to 2.22%.

The authors suggest rising myopia, already reported from the same programme, as the reason exotropia is increasing.

In 2013–14, 342 children had a binocular vision anomaly and presenting vision good enough to pass a letter-chart screen, and 512 did in 2021–22: between 23.2% and 32.7% of the anomalies found each year.

Orthoptist vs optometrist: who does what

Orthoptists specialise in eye movements and binocular vision, work mainly in hospital eye departments alongside ophthalmologists, and deliver children's vision screening where eye care professionals do it, as across Scotland. Some refract as well. A 2025 study for the General Optical Council, two focus groups of 16 eye care professionals and students, found some orthoptists already refracting young children in hospital clinics, mostly by cycloplegic retinoscopy. The Opticians Act lets only optometrists and registered medical practitioners issue a spectacle prescription, so an ophthalmologist or optometrist signs it.

Optometrists see children in community practice, where the cover test belongs in every child's sight test. The evidence on their referrals is thin but encouraging. In a 2023 review of optometrists' referral accuracy, the one UK study of children's binocular vision referrals found that 88.9% of 45 optometrist referrals matched the hospital's diagnosis in full or in part, against 65% of GP referrals. Earlier pieces on referral from community practice cover the adult side.

When a squint needs referring, and how fast

NICE's guideline on suspected neurological conditions sets four rules for children. A new squint with loss of the red reflex in either eye goes to ophthalmology immediately. A new squint with ataxia, vomiting or headache goes to acute paediatric services immediately. A paralytic squint is referred urgently for neurological assessment, even without other signs of raised intracranial pressure. A non-paralytic squint is referred to ophthalmology services.

The College of Optometrists' urgency table puts acute onset squint or nerve palsy, new, sudden or worse, in its emergency column, within 24 hours, so a new paralytic squint falls under both. NICE gives no timescale for a non-paralytic squint without those signs, and in my view a long-standing one found at a routine test can go as a routine referral, with the findings the orthoptist will need.

Why it matters in practice

• Cover test every child at distance and near. In the Scottish data, up to a third of the binocular anomalies came with vision good enough to pass a letter chart.
• Intermittent exotropia more than doubled in the Scottish data, and because it comes and goes, ask the parents when the eye drifts and whether they have a photograph of it.
• Onset decides the speed: whether the squint is new, sudden or worse, whether it is paralytic, the red reflex, and headache, vomiting or unsteadiness.
• Write the letter the orthoptist needs: direction, constant or intermittent, distance and near, onset, visual acuity, the refraction and whether it was cycloplegic, and the red reflex.

The caveats

• These are screening records, not diagnoses, and the study had no data on false negatives.
• Scotland only, eight of 15 health boards and a mainly Caucasian sample, with no data for 2016 to 2020. Fewer eligible children attended after the pandemic, and screening in 2020–21 ran late.
• The study had funding support from Hoya, and two authors have received research and consultancy funding from Hoya Vision Care.
• The referral accuracy figure is one UK study of 45 referrals, and the refraction findings come from two focus groups of 16 eye care professionals and students.

Sources

1. 1.Binocular Vision Anomalies in Scotland at Age 3.5–5.5 Years: An Epidemiological Study · Ophthalmic and Physiological Optics, 30 March 2026
2. 2.Suspected neurological conditions: recognition and referral (NG127). Recommendations for children aged under 16 · NICE, 1 May 2019
3. 3.Annex 4 Urgency of referrals table (Guidance for Professional Practice) · College of Optometrists
4. 4.The Role of Orthoptists in Refraction · British and Irish Orthoptic Journal, 14 February 2025
5. 5.Assessment of optometrists' referral accuracy and contributing factors: A review · Ophthalmic and Physiological Optics, 3 July 2023
6. 6.Squint · NHS, 2 May 2023