Box 1.

Description of the pathways compared within the economic model.

Glaucoma Screening Platform Study (GPS)1. (Tonometry (measurement of intraocular pressure (IOP)) and optic nerve photography (ONP)): The population to be screened are invited to a primary care setting to undergo tonometry and ONP by a technician or nurse who has received some training. Screen positives referred to hospital eye service.

GPS11 (IOP and visual field (VF)): As above but screening with tonometry and visual field test (perimetry). Screen positives referred to hospital eye service.

GPS1d (IOP + ONP): Screening with tonometry and optic nerve photography and screen positives examined by a specialized optometrist (diagnosis). Diagnostic test positives referred to hospital eye service.

GPS11d (IOP + VF): Screening with tonometry and visual field test (perimetry) with further diagnostic refinement and screen positives examined by a specialized optometrist (diagnosis). Diagnostic test positives referred to hospital eye service.

Current practice (UK NHS eye care): Opportunistic sight test at community optometrist with referral of suspect glaucoma to the hospital eye service.

IOP ≥ 26 mmHg = screen positive.

IOP < 26 mmHg + second technology test positive = screen positive.

IOP < 26 mmHg + second technology test negative = return to current eye care and re-screen cycle.