IOP (GAT) Refinement (Level 1)

The Repeat IOP service aims to reduce unnecessary referrals to secondary care for suspect ocular hypertension/glaucoma.

Patients found to have raised IOP (24mmHg - 31mmHg) and no other signs of glaucoma during their NHS or private sight test, can be offered an applanation IOP measurement at the same visit. 

If the raised IOP is confirmed to be in the same range, a further repeat measurement should be offered within 4 weeks, before considering referral to ophthalmology.

Practitioners accredited to level 1 can offer the Repeat IOP service to their (the practice's) own patients only

For a patient seen by a non-accredited practitioner/practice who has IOPs 24 - 31mmHg  please refer to a level 2 accredited optometrist, for the enhanced case finding service, not the GP or hospital, to avoid unnecessary hospital referrals. A list of level 2 accredited practices and practitioners is available here.

Although GAT is a core competency, practitioners providing the service must become accredited to level 1, by completing the WOPEC IOP module - a free access code is available by emailing, and be confident providing applanation tonometry.

If raised IOP is confirmed, patients can be referred direct to an ophthalmology service using the Repeat IOP (GAT) Referral form, with a copy being sent to the GP.

Fees paid

  • first measurement  - £20 (same day as sight test)
  • second measurement  - £25 (repeat visit within 4 weeks)


If you would like to offer the service and have not yet applied, please conatct Victoria Ajayi at