Ocular hypertension (OHT)


Ocular hypertension (OHT) is generally defined as consistently elevated intraocular pressure (IOP) (greater than 21mmHg [2 standard deviations above the population mean IOP] by Goldmann applanation tonometry [GAT] on 2 or more occasions) in one or both eyes in the absence of clinical evidence of optic nerve damage, visual field defect or other pathology that could explain high IOP.
Aetiology unknown
The population prevalence estimates for OHT range from 4.5% to 9.4% for those aged > 40 years, with prevalence increasing with age. Data from longitudinal studies indicates that 10% of persons with untreated OHT develop primary open angle glaucoma (POAG) in 5 years.

Predisposing factors

Increasing age

Symptoms of ocular hypertension

Usually asymptomatic

Signs of ocular hypertension

An untreated IOP >21mmHg (GAT), in one or both eyes confirmed on a separate occasion
Open drainage angles on gonioscopy with normal appearance
Absence of signs of glaucomatous optic neuropathy (disc changes, field defects)
Absence of secondary cause for IOP elevation

Differential diagnosis

Chronic Open Angle Glaucoma (COAG)
Primary Angle Closure (PAC) or Primary Angle Closure Glaucoma (PACG) (i.e. without or with glaucomatous disc damage)
Secondary Open Angle glaucoma (eg steroid responder, pigment dispersion, pseudo-exfoliation)
See relevant Clinical Management Guidelines

Management by optometrist

Practitioners should recognise their limitations and where necessary seek further advice or refer the patient elsewhere

GRADE* Level of evidence and strength of recommendation always relates to the statement(s) immediately above

Non pharmacological

Guidance on OHT is included in National Institute Health and Care Excellence (NICE) guideline (NG81, November 2017): Glaucoma: diagnosis and management; Scottish Intercollegiate Guidelines Network guideline (SIGN 144, March 2005): ‘Glaucoma referral and safe discharge’ (see Evidence Base); and guidance produced by the College of Optometrists: ‘Examining patients at risk from glaucoma’. NICE guideline NG81 also provides detailed guidance on the diagnosis and management of OHT (including monitoring intervals).

The following guidance on management of OHT is based on NICE NG81, however for optometrists in Scotland SIGN 144 provides specific guidance for referral and management of OHT.

In the case of onward referral for OHT, refer only if IOP is 24mmHg or more using Goldmann-type applanation tonometry. Advise people with IOP below 24 mmHg to continue regular visits to their primary eye care professional (NICE recommendation).
(GRADE*: Level of evidence=low, Strength of recommendation=strong).

For diagnosis of OHT, patients should be offered the following tests: central visual field assessment using standard automated perimetry; optic nerve assessment and fundus examination using stereoscopic slit lamp biomicroscopy (with pupil dilatation if necessary); optical coherence tomography (OCT) or optic nerve head imaging if available; intraocular pressure (IOP) measurement using Goldmann-type applanation tonometry; peripheral anterior chamber configuration and depth assessments using gonioscopy or, if not available or the patient prefers, the van Herick test or OCT. (NICE recommendation)
(GRADE*: Level of evidence=low, Strength of recommendation=strong)

People with OHT can be monitored (and treated) by a trained healthcare professional who has all of the following: a specialist qualification in glaucoma; relevant experience; ability to detect a change in clinical status (NICE recommendation).
(GRADE*: Level of evidence=low, Strength of recommendation=strong)

At each assessment, re-evaluate risk of conversion to POAG and risk of sight loss to set time to next assessment. (NICE recommendation)
(GRADE*: Level of evidence=low, Strength of recommendation=strong)

Data from the Ocular Hypertension Treatment Study (OHTS) and the European Glaucoma Prevention Study (EGPS) have been used to produce a risk calculator to predict the five-year risk of developing POAG in adult patients with ocular hypertension. All of the variables included in the prediction model can be routinely collected in clinical practice, i.e. age; IOP; central corneal thickness (CCT); vertical cup-to-disc (C/D) ratio and pattern standard deviation (PSD). The risk calculator is available online https://ohts.wustl.edu/risk/.

Offer people the opportunity to discuss their diagnosis, referral, prognosis, treatment and discharge, and provide them with relevant information in an accessible format at initial and subsequent visits. (NICE recommendation)
(GRADE*: Level of evidence=low, Strength of recommendation=strong)

A recent large UK RCT (LiGHT study) found that primary selective laser trabeculoplasty (SLT) is a cost-effective alternative to ocular hypotensive drops that may be offered to patients with open angle glaucoma or OHT needing treatment to lower intraocular pressure.
(GRADE*: Level of evidence=moderate, Strength of recommendation=strong)


Offer a generic prostaglandin analogue to people with an IOP of 24mmHg or more if they are at risk of visual impairment within their lifetime, taking into account risk factors such as: level of IOP, CCT, family history, and life expectancy. (NICE recommendation)
(GRADE*: Level of evidence=high, Strength of recommendation=strong)

Management category

Patients should have referral filtering (e.g. repeat measures, referral refinement) before they are referred to the HES (NICE recommendation)

B1 (modified): no intervention, routine referral to a consultant ophthalmologist or to an optometrist with a specialist qualification in glaucoma
B2: alleviation or palliation, no referral

Possible management by ophthalmologist

Confirmation of diagnosis
Determination of the individual clinical management plan 
Reduction of IOP pharmacologically in patients at moderate or high risk of conversion to COAG
Selective laser trabeculoplasty (SLT)

Evidence base

*GRADE: Grading of Recommendations Assessment, Development and Evaluation (www.gradeworkinggroup.org)

Sources of evidence

Burr JM, Botello-Pinzon P, Takwoingi Y, Hernández R, Vazquez-Montes M, Elders A, et al. Surveillance for ocular hypertension: an evidence synthesis and economic evaluation. Health Technol Assess 2012;16(29)

Garg A, Vickerstaff V, Nathwani N, Garway-Heath D, Konstantakopoulou E, Ambler G, Bunce C, Wormald R, Barton K, Gazzard G; Laser in Glaucoma and Ocular Hypertension Trial Study Group. Efficacy of Repeat Selective Laser Trabeculoplasty in Medication-Naive Open-Angle Glaucoma and Ocular Hypertension during the LiGHT Trial. Ophthalmology. 2019 Oct 30. pii: S0161-6420(19)32181-5. doi: 10.1016/j.ophtha.2019.10.023. [Epub ahead of print]

Gazzard G, Konstantakopoulou E, Garway-Heath D, Garg A, Vickerstaff V, Hunter R, Ambler G, Bunce C, Wormald R, Nathwani N, Barton K, Rubin G, Buszewicz M; LiGHT Trial Study Group. Selective laser trabeculoplasty versus eye drops for first-line treatment of ocular hypertension and glaucoma (LiGHT): a multicentre randomised
controlled trial. Lancet. 2019;393(10180):1505-1516

Vass C, Hirn C, Sycha T, Findl O, Sacu S, Bauer P, Schmetterer L. Medical interventions for primary open angle glaucoma and ocular hypertension. Cochrane Database of Systematic Reviews 2007:4:CD003167

For recommendations regarding OHT diagnosis and management, refer to: NICE Guideline NG81 (2017). Glaucoma: diagnosis and management 

Scottish Intercollegiate Guidelines Network (SIGN). Glaucoma referral and safe discharge. Edinburgh: SIGN; 2015. (SIGN publication no. 144, March 2015) 

Plain language summary

If a person has a consistently raised eye pressure but no signs of glaucoma, he or she is said to have Ocular Hypertension (OHT). This is not glaucoma, as there is no damage to the optic nerve (the nerve of sight), but untreated OHT nevertheless leads to Primary Open Angle Glaucoma (POAG) in 10% of patients within five years.

Both the National Institute for Health and Care Excellence (NICE) and the Scottish Intercollegiate Guidelines Network (SIGN) have produced detailed advice on the diagnosis and management of this condition. The optometrist can predict the risk of a patient with OHT developing POAG within five years with the aid of a risk calculator that is available online.

An optometrist who diagnoses a case of OHT and who believes that there is a moderate or high risk of progression to POAG may decide to refer the patient to an ophthalmologist or an optometrist with a specialist qualification in glaucoma. The case can then be re-assessed and, if necessary, pressure-lowering medications or laser surgery can be offered.

Ocular hypertension (OHT)
Version 8
Date of search 15.03.20
Date of revision 26.03.20
Date of publication 23.07.21
Date for review 14.03.22
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