Glaucoma and Ocular Hypertension

7) Guideline for Suspected Glaucoma/Ocular Hypertension Referral in Birmingham


NB because of delays caused by the general referral system into BMEC the glaucoma consultants have introduced  a fast track glaucoma referral service.  They have also introduced a form specifically for glaucoma referrals please access this via the "Forms" page.  You may use the BMEC form or the normal GOS 18 form but the referral should be faxed to 0121 507 6726


7.1 In order to have reached a decision that glaucoma or ocular hypertension exists you should have, as an absolute minimum, carried out the following:


  • Measurement of intra ocular pressure (IOP)
  • Assessment of the optic disc
  • Automated Threshold/)Suprathreshold Visual field screening


Other procedures that may help to confirm your diagnosis and could, therefore, be usefully performed include:


  • Relative colour vision
  • RAPD
  • Assessment of anterior chamber depth using Van Herick
  • Gonioscopy
  • Pachymetry (It is accepted that this is unlikely to be available in many practices but is now becoming increasingly common).
  • OCT assessment of the optic disc and anterior chamber (these instruments are now becoming increasingly common in primary care optometry practice).


7.2 Wherever possible, especially when your initial tests prove to be inconclusive, elevated IOP should be confirmed using Goldmann applanation tonometry, the disc should be assessed using dilated slit lamp bio-microscopy (digital imaging may also help) and a threshold visual field should be carried out (suprathreshold field if threshold not available). The patient may be given a second appointment for these extended tests if necessary.  Should you be unable to offer any of these tests referral to a nearby colleague who can would be appropriate.  Where your suspicion of glaucoma is confirmed referral to the chosen ophthalmology department (or local glaucoma referral centre) should be undertaken indicating how soon, in your opinion, the patient should be seen.  Please remember that a referral for suspected primary open angle glaucoma is not an emergency and it is not a problem for these patients to be seen “in turn”.


7.3 Indications for Referral


(a)      Emergency referral


  • Acute glaucoma (angle closure or secondary such as rubeotic).


(b)      Urgent referral


  • Confirmed IOPs measuring over 31 mm Hg but no acute signs.


  • Symptoms suggestive of angle closure in the presence of clinically narrow angles as assessed by slit-lamp (Van Herick, or preferably, gonioscopy) i.e. intermittent pain/brow ache, blurring or coloured haloes (particularly at night). Where available assessment of the drainage angle using an OCT linear scan will be helpfull.


  • Raised IOP in the presence of signs of chronic uveitis.


  (c)      Routine Referral


i) Elevated intra ocular pressure


In 2009 NICE issued clear guidance relating to the procedures to be followed for patients with Ocular Hypertension and/or suspected Primary Open Angle Glaucoma.


Whereas previously the decision as to whether a patient found to have an elevated IOP but no other signs of glaucoma had been left to the clinical judgement of the examining optometrist, the new guidance gave clear instructions relating to the referral of patients found to have an IOP in excess of 21 mm Hg.


The Association of Optometrists immediately issued a statement that all optometrists should follow the new guidance to the letter or run the risk of being sued should a patient retained for in practice monitoring of assumed ocular hypertension later be found to have glaucoma.


The resulting flood of referrals swamped ophthalmology departments across the country and, to alleviate that situation, enhanced services were established in some areas to reduce those referrals by repeating tonometry readings using Goldmann type Applanation tonometry once or twice before deciding to refer.


The Birmingham and Solihull (BSOL) cluster of PCTs implemented such an IOP repeat measures enhanced service, based on NICE guidance and using the LOCSU level 1a pathway, commencing on 1st June 2012.


In order to participate in this enhanced service practitioners must be accredited either by undertaking the Wales Optometry Postgraduate Education Centre (WOPEC) training and accreditation or by other forms of acceptable prior experiential learning, these include the Aston University in practice doctorate glaucoma module plus a skills assessment carried out by one of the Birmingham based glaucoma specialists, the College of Optometrists Glaucoma Diploma certificate A or other qualifications for which a letter confirming the ability to perform the necessary skills and signed by a consultant ophthalmologist may be required. Please contact the LOC Secretary on for the code required to commence the WOPEC training and accreditation or if you feel that you may already be qualified to participate.





Full details of the service protocols are available from the BLOC Secretary on application but the brief requirements are as follows.


Patients found to have elevated IOP during a routine eye examination using any type of tonometer should have the measurement repeated using Goldmann type Applanation Tonometry at a later time on the same day. If the second measurement finds the IOP to be within normal age related limits the patient should be discharged and a fee of £20.00 can be claimed.


Those found to still have an elevated IOP on the second measurement should be asked to return for a further measurement on another day and if, using Goldmann type Applanation Tonometry an elevated IOP is still found, a referral to a consultant ophthalmologist for formal diagnosis of ocular hypertension should be made. Where at the second visit the IOP is found to be within normal age related limits the patient should be discharged.   Either way, whether the patient is referred or not a fee of £25.00 can be claimed to cover the cost of the additional appointment.


For your reference the full LOCSU OHT/COAG pathway can be seen at Appendix 2 but do please remember that, until further notice, BSOL cluster has only authorised level 1a as an enhanced service and references to level 1b and beyond should be ignored.




ii) Field defect in the absence of anomalous discs and elevated IOP.


Threshold visual field defects should be carefully assessed and every attempt made to determine their aetiology. Remember that field defects can have many causes, by no means all of which are associated with glaucoma.


Unless you can be absolutely sure that there is a reasonable explanation for the field defect which does not require referral, e.g. hemianopia as a result of a stroke already known to the GP or tilted discs, all field defects should be referred for assessment by an ophthalmologist.


Where, in your opinion, the condition causing the defect might be sight or life threatening then an emergency (same day) referral to an eye casualty department or an urgent (faxed accompanied by a telephone call) referral to the chosen ophthalmology department should be made.


In the absence of other diagnostic signs, visual field defects should be confirmed by at least one repeat measurement before referring.


iii) Anomalous disc appearance in the absence of elevated IOP and field defect.


There are many congenital conditions resulting in anomalous optic disc appearance e.g. disc coloboma, optic disc drusen and tilted discs. Pale discs may be a result of previous optic neuritis etc.


It is appropriate to monitor some anomalous discs (e.g. tilted discs) annually but most cases will need no special attention.


It would be inappropriate to refer a patient as a glaucoma suspect on disc appearance alone. One exception, however, is a splinter haemorrhage at the disc margin which should be referred as an urgent case, preferably with an image to prove the existence of the haemorrhage since these have a habit of reabsorbing before they are seen by an ophthalmologist.


Optic disc assessment is best performed using a slit-lamp with an indirect viewing system, retinal photography, OCT or all three.


7.4 If your initial screening results are unequivocal, an immediate referral to the chosen ophthalmology department or local primary eye care referral refinement scheme should be undertaken, indicating that the patient should be seen “urgently” “soon” or “in turn”.                                                                                                                                                                                                                                                                                                                                                          


7.5 You may, at this stage, offer the patient a choice of provider for glaucoma services, you will know which ophthalmology unit most of your patients are normally referred to and should continue to refer to that unit.  Alternatively your PCT will be able to advise you on which provider is the most appropriate for you to refer into.


7.6 Key Factors in Glaucoma


  • Primary open angle glaucoma can occur at any intraocular pressure.
  • The higher the measured IOP the more likely it is that the patient will have glaucoma or require treatment to prevent it.
  • Approximately 5% of the over 50s will have an IOP measured greater than 21 mmHg on a single visit.
  • Patients with or without glaucoma tend to have higher IOPs in the morning due to diurnal changes.
  • Subtle optic disc changes may precede visual field defects.


7.7 Common Causes of Diagnostic Confusion and Misinterpretation of Test Results


  • Some patients become very tense when undergoing tonometry for the first time and tend to record higher IOPs.
  • Isolated visual field defects are common in normals as are superior defects due to “droopy” eye lids and rim defects caused by the trial lens.
  • Beware of confusing large physiological cups with changes caused by glaucomatous excavation.


This document is intended as guidance only. Individual practitioners must make their own clinical judgements and should always err on the side of caution.


7.8 If in doubt refer, but only after very careful consideration of all the evidence


LOCSU Glaucoma Repeat Readings &

OHT Monitoring Enhanced

Service Pathway

Issued by

Local Optical Committee Support Unit May 2009

[Revised June 2012]



PageExecutive Summary  3

Background........................................................................................... 4

NICE Guidance and Quality Standards .................................................  4

IOP referrals....................................................................................... 4

Tonometry methods............................................................................. 5

Outline of Service...................................................................................................... 5

Key Drivers............................................................................................ 6

Description............................................................................................ 7

Level 1a: Goldmann style applanation tonometry.................................... 7

Level 1b: Visual field repeat readings.................................................... 9

Level 1 c: Non-participating practices ...................................................... 9

Level 2: OHT & suspect COAG Monitoring............................................ 10

Patient Records................................................................................... 12

IT System........................................................................................... 12

Special requirements - equipment......................................................... 12

Patient information............................................................................... 12

Appendix 1: IOP and Visual Field Pathway............................................. 13

Appendix 2: Non-Participating Practices............................................... 14

Appendix 3: OHT Monitoring Pathway................................................... 15

Appendix 4: Clinical Management Guideline Level 1 .............................  16

Appendix 5: Clinical Management Guideline Level 2 ............................. 18

Appendix 6: Core Competencies for Optometry.................................... 19


Executive Summary

In order to facilitate a reduction of referrals of suspect glaucoma to the Hospital Eye Service and to increase “care in the community” for glaucoma related conditions LOCSU recommends the implementation of care pathways for Glaucoma Repeat Readings and Ocular Hypertension (OHT) Monitoring.

The aim of a glaucoma repeat readings pathway is to reduce false positive referrals to the hospital eye service, reducing patient anxiety and increasing capacity within the overburdened hospital glaucoma clinics. This should provide a more cost- effective service with a greater number of patients managed within the primary care setting. Evaluation of data in Stockport1, Bexley2 and North of Tyne3 PCTs shows that a reduction in referrals of up to 76% can be expected following implementation of a Glaucoma Repeat Readings service provided by community optometrists.

The pathway allows accredited optometrists to repeat diagnostic tests to confirm the risk of disease and thus improve the accuracy of referrals and deflect unnecessary referrals. The first two Quality Statements of the NICE Quality Standards for glaucoma recommend local agreements for referral refinement & repeat measurements.

The aim of an OHT monitoring pathway is to reduce the number of secondary care consultations for the cohort of patients who are diagnosed as having OHT i.e. consistently high intra-ocular pressures (IOP) but no glaucoma. Currently, patients who are considered to have a greater chance of developing glaucoma due to elevated IOP or other suspicious signs are generally retained in secondary care and reviewed there on an annual basis, following referral in.

The OHT monitoring service allows patients with diagnosed OHT to be discharged back into primary care for monitoring by community optometrists. Patients would only be referred back into secondary care if there was a change in clinical status.

1 Repeating pressures- an electronic reporting system. T J Warburton. Optometry Today, 17th September 201

2 Comparison of the effectiveness of two enhanced glaucoma referral schemes David J Parkins and David F Edgar. Ophthalmic & Physiological Optics 31 (2011) 343–352

3 Local audit data, NHS North of Tyne



Affecting an estimated 480,000 people in England, Chronic Open Angle Glaucoma (COAG) is a common condition involving optic nerve damage and loss of the visual field that can lead to blindness if it’s not diagnosed early and treated promptly. Around 14% of UK blindness registrations are due to glaucoma. However many people won’t know that their eyesight is at risk – there are usually no symptoms until the later stages when their vision is already seriously damaged. OHT (raised pressure in the eye) is a major risk factor for developing COAG, although COAG can occur with or without raised eye pressure. Glaucoma is more common with increasing age, and people of African descent or with a family history of glaucoma may be at greater risk of developing the condition. With changes in population demographics the number of people affected by the condition is expected to rise.

NICE guidance and quality standards

NICE clinical guideline 85 (Diagnosis and management of chronic open angle glaucoma and ocular hypertension) issued 22 April 2009 sets out how best to diagnose COAG and OHT, how people with COAG, OHT or at risk of COAG, should be monitored, and which treatments should be considered.

The first two Quality Statements of the NICE Quality Standards for glaucoma recommend local agreements for referral refinement & repeat measurements.

IOP referrals

Currently due to the constraints of a GOS sight test, and recent NICE guidelines, optometrists are referring all cases of suspect glaucoma and OHT to secondary care for confirmation of the diagnosis and treatment where necessary. This works well when the diagnosis is positive. However, there is no simple single test for glaucoma and this, coupled with the low prevalence of the condition, makes it difficult to detect with certainty in the early stages. Referral refinement has been shown to reduce onward referrals by as much as 77%3 . OHT is defined in the NICE guidance as repeatable intra-ocular pressure over 21 mmHg as measured by Goldmann applanation tonometry (GAT). By defining the criteria and procedures for diagnosis, NICE have, by implication, created a referral threshold. Previously the threshold for OHT was set by local ophthalmologists and in many cases was around 25 mmHg. This lowering of the effective threshold has increased the number of referrals by community optometrists who are now following the NICE guideline.


Tonometry methods

Most optometrists measure the pressure using an air-puff tonometer. These are considered by NICE to be less accurate, and so repeating the pressures using Goldmann style tonometry will reduce the number of false positive referrals. The use of Goldmann style tonometry is not a requirement of a GOS sight test, although it is a core competency of optometrists.

Only a small number of practices have a slit lamp Goldmann applanation tonometer (GAT) but a greater number may have a Perkins which is a hand held applanation tonometer based on the Goldmann prism principle. Maximum participation is very important for the success of a repeat IOP scheme and it would be correct to say that NICE only insist on slit lamp GAT for diagnosis and monitoring. The entire guideline is silent on referral but it is covered by the first two Quality Statements. IOP refinement requires accurate repeat readings; therefore repeat measures using either slit lamp GAT or Perkins will be acceptable. It should be stressed that the use of any other type of tonometer for repeat measures in an NHS funded enhanced service should be avoided.

Outline of Service

The proposed Level 1 service would provide primary care repeat readings to deflect unnecessary referrals to secondary care and is within the basic competency of community optometrists.

The proposed Level 2 service would provide primary care monitoring for patients diagnosed with OHT that does not require treatment.

Some refreshment of skills may be required depending on the service. Both services would be below secondary care PbR tariff.


Key Drivers

The national key drivers include:

  • NICE clinical guideline 85: Diagnosis and Management of Chronic Open Angle

Glaucoma and Ocular Hypertension

  • NICE Quality Standards: Glaucoma
  • Equity & Excellence: liberating the NHS (2010)
  • Right Care: Increasing Value – Improving Quality (June 2010)
  • NHS 2010-15 ; from good to great
  • Operating framework for the NHS in England 2010/11
  • Quality Innovation Productivity & Prevention (QIPP) agenda
  • HM Treasury (2010) The Spending Review Framework
  • Creating a patient-led NHS: Delivering the NHS Improvement Plan (March 2005)
  • Commissioning Framework for 2007-8
  • Implement care closer to home; convenient quality care for patients (April 2007)
  • Commissioning Framework for health and well-being (March 2007)
  • Trust, Assurance and Safety – the Regulation of Health Professionals (February


  • Safeguarding patients ( February 2007)



Level 1 a: Goldmann style applanation tonometry repeat readings

A first level enhanced service for IOP refinement where other signs of glaucoma are not present will reduce unnecessary referrals to the hospital eye service, reducing patient anxiety and minimising capacity issues within the already overburdened hospital glaucoma clinics. The service will be cost effective with a greater number of patients managed within the primary care setting.

Level 1a (Part 1)

Patients who are identified as having IOP > 21 mmHg and no other signs of glaucoma during a GOS or private sight test will have immediate slit lamp GAT or Perkins tonometry assuming the optometrist is contracted to provide the service. This service falls within core competencies for optometrists. Set up costs of purchasing tonometers should be considered.


Guidance from the College of Optometrists and the Royal College of Ophthalmologists recommends that the outcome should be dependent on the patient’s age and they define certain groups who may not need referral. However, pressures should still be repeated on these groups to ensure that decisions are made based on reliable readings.

There are four possible outcomes from this first repeat of pressures:

  1. All patients with IOP > 31 mmHg should be referred for OHT diagnosis without further IOP refinement
  2. Other patients with a pressure of 22 - 31 need to proceed to Part 2 (2nd repeat pressure)
  3. Pressures which differ between the eyes by 5 mmHg or more should proceed to Part 2 (2nd repeat pressure)
  4. All other IOP results are within normal limits and the patient can be discharged.

At risk groups should be monitored at appropriate intervals.

Level 1a (Part 2)

Patient attends for repeat Goldmann or Perkins applanation tonometry on a separate occasion.



There are four possible outcomes from repeating this test:


Patients who need to be referred for OHT diagnosis based on confirmed IOP result:

Age Group

< 65 years

65 79 years

80 years +


> 21 mmHg

> 24 mmHg

> 25 mmHg

Patients who can be referred direct to the OHT monitoring service assuming there is a service in place:


Age Group


65 79 years


80 years +








22 - 24 mmHg


22 - 25 mmHg


NB: The Joint RCOpht/COptom's advice suggest that optometrists might "consider not referring" this group of patients as under the NICE Guidelines they will never need treatment. Whilst this is true, these patients however do still have OHT and need careful monitoring to pick up any signs of progression towards COAG. It is not appropriate to monitor these patients under GOS.

These patients are not really in any of the groups specifically covered by NICE but the most appropriate way to deal with them is to make the assumption that the College's advice constitutes the establishment of a "management plan" as per para 1.5.6 of NICE CG85 and monitor these patients as having diagnosed OHT.

  1. Where repeat applanation measurements show a consistent difference in pressure of 5 mmHg or more, practitioners may wish to consider whether referral may be appropriate, or whether there is a reasonable explanation (e.g. surgery to one eye).
  2. The results are within normal limits and the patient can be discharged. At risk groups should be monitored at appropriate intervals.

The criteria for inclusion of patients in level 1 a:

  • IOP > 21 mmHg as measured at the sight test following College guidance on technique where NCT is used (4 readings), and no other signs of glaucoma are present.


Level 1 b: Visual field repeat readings

A first level enhanced service for visual field refinement will reduce unnecessary referrals to the hospital eye service, reducing patient anxiety and minimising capacity issues within the already overburdened hospital glaucoma clinics. The service should be cost effective with a greater number of patients managed within the primary care setting.

Patients who are identified as having suspicious visual fields during a GOS or private sight test will have visual fields repeated on a separate occasion assuming the optometrist is contracted to provide the service This service falls within core competencies for optometrists


There are three possible outcomes from these tests:

  1. The results are within normal limits and the patient can be discharged. At risk groups should be monitored annually under GOS. (This would include the case where there is a defect on the repeat but NOT in the same areas of the visual field as the original defect. Such inconsistent defects are usually due to the patient finding the test difficult and should not, as a rule, lead to referral and further repeats/monitoring may well just add further confusion.)
  2. Visual field is suspicious and requires monitoring at appropriate intervals
  3. Visual field defect is confirmed and the patient is referred to consultant ophthalmologist.

The criteria for inclusion of patients in level 1 b

  • Visual field defect which may be due to glaucoma and requires further investigation, and no other signs of glaucoma are present. (Defects caused by old pathology or lens rim artefacts should be excluded.)

Level 1 c: Patients from non-participating practices

It is anticipated that the majority of optometrists will participate in the Level 1 a or 1 b pathway if it is commissioned, assuming refresher training is available and funding is appropriate. However a small minority of practices may decide not to sign up to the pathway. Commissioners may look to accredited practitioners to provide referral refinement for patients from non-participating or out-of-area practices.


In this case it should be emphasised that the second optometrist assumes clinical responsibility for the detection of the patient suffering from glaucoma or ocular hypertension. Therefore assessment of the optic disc, anterior angle and where appropriate, visual field is necessary.

These additional examinations required will take more time and will require a greater level of funding than Level 1 a or 1 b. (Please see guidance from the Association of Optometrists and the Optical Confederation on insurance issues.)

The criteria for inclusion of patients in level 1 c

  • IOP > 21 mmHg as measured at the sight test following College guidance on technique where NCT is used (4 readings), and no other signs of glaucoma are present or visual field defect which may be due to glaucoma

and requires further investigation, and no other signs of glaucoma are present.

NB: Glaucoma is a very slow developing disease and there is very little risk to the patient in delaying the repeat tests. The reason for repeating the tests on a different occasion is to ensure that factors that may have influenced the patient responses the first time round, particularly in the fields test, will be different.

Level 1 accreditation

The procedures and skills required for level 1 are core competency. That doesn't necessarily mean that every practitioner is completely up to date in those areas and/or has any recent experience of the techniques. LOCSU would expect most areas to introduce repeat IOP and fields, with no accreditation requirement at all beyond a refresher for those who require it. Others may require some form of accreditation. However it should be noted that, for Level 1a in particular, a very high level of participation is the key to successful referral deflection. Placing barriers to participation at core competency level may affect the success of the scheme. If accreditation at this level is required, it must be available rapidly to new practitioners in an area. Typical professional staff turnover within an area can be around 10% per year. A LOCSU training and accreditation package for Level 1

IOP repeat readings and Level 2 OHT monitoring has been developed in conjunction with the Welsh Optometric Post-graduate Education Centre (WOPEC), and is available to optometrists in England and Wales via their LOC or ROC.

Level 2: OHT and suspect COAG monitoring

Patients who have a confirmed diagnosis of OHT or suspect COAG and who do not require treatment should follow the OHT or suspect COAG monitoring pathway and be monitored at regular intervals as specified by NICE. Patients will be referred to this pathway from the community OHT diagnostic clinic or secondary care with an individual management plan.


It is further recommended that patients falling into the 2 groups that the Colleges suggest may not need referral should be directed straight into this service rather than refer them for diagnosis.

The skills required for this pathway are covered by the core competencies for optometrists. Training and accreditation for optometrists would include knowledge of the NICE guidelines, referral criteria, interpretation of results and the disease process. If a change in clinical status is found, the patient should be referred to a specialist community optometrist or hospital eye department for further investigation, depending on local protocol. This service will reduce unnecessary hospital eye service consultations and minimise capacity issues in secondary care. Set up costs of purchasing slit lamp mounted Goldmann tonometers should be considered.

The accredited optometrist will carry out slit lamp mounted Goldmann tonometry, suprathreshold perimetry, Van Herick’s test, and dilated slit lamp biomicroscopic examination of the optic nerve head.


There are two possible outcomes from these tests:

  1. No change in clinical status. Next appointment as per protocol.
  2. Change in clinical status. Patient referred to specialist optometrist or hospital clinic depending on local arrangement.

The criteria for inclusion of patients may include the following:

  • Diagnosed ocular hypertension discharged from hospital eye service (HES) or specialist practitioner
  • Diagnosed suspect COAG discharged from HES or specialist practitioner

Level 2 accreditation

With OHT monitoring, although the skills are still core competencies, LOCSU would expect most areas to require accreditation in the form of a validation of knowledge and skills. A LOCSU training and accreditation package for Level 1 referral refinement and Level 2 OHT monitoring has been developed in conjunction with the Welsh Optometric Post-graduate Education Centre (WOPEC), and is available to optometrists in England and Wales via their LOC or ROC. This package includes distance learning via CD–Rom and a template for practical skills assessment in slit lamp GAT, disc assessment and Van Herick’s technique. A number of Lead Assessors have been trained at WOPEC so that the practical assessments can be organised locally when required.


Patient records

All advice given to the patient, and procedures undertaken should be recorded on a patient card or electronic device, and stored in a safe retrieval system.

On conclusion of an IOP repeat readings or OHT monitoring assessment the optometrist must complete the appropriate report form, entering the information on the IT system for audit purposes (where applicable) and report to the referring GP, and to the hospital eye service, should an onward referral be necessary. For full NICE compliance there should be disc images taken close to the time of discharge to the monitoring scheme which are available as a baseline measure.

IT system

LOCSU has developed an electronic patient record for Level 1 which is currently in use in areas such as Stockport. This IT platform will standardise data collection and will ensure audit data is readily available. It can generate paper referrals or can provide for electronic referral via a referral management centre. Work on extending the Level 1 IT platform to support the Level 2 pathway is nearing completion.

Special requirements – equipment

All practices participating in the Level 1 IOP repeat readings service and the Level 2 OHT monitoring service will be expected to employ an accredited optometrist and have the following equipment available:

  • Access to the Internet
  • Slit lamp and fundus viewing lens
  • Goldmann applanation tonometer (Perkins acceptable for IOP refinement)
  • Threshold fields equipment capable of producing a printed report
  • Distance test chart
  • Appropriate ophthalmic drugs (Mydriatic, Anaesthetic, Staining agents)

Patient information

Patient information leaflets as recommended by NICE will be available to patients.


Appendix 1


Appendix 2

Patients from Non-Participating Practices

Patient attends for GOS or private eye test at a non-participating practice




IOP > 21 mmHg Optic nerve head normal Visual field normal

Any other signs of glaucoma (regardless of IOP)




21 mmHg Age 65-79 IOP > 24 mmHg " src="data:image/png;base64,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" hspace="36" v:shapes="_x0000_s1053"> 31 mmHg or other sign of glaucoma " src="data:image/png;base64,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" hspace="62" v:shapes="_x0000_s1063">

Patient referred to community optometrist enhanced service provider for referral refinement

Examination to include:

Assessment of IOP by Goldman or Perkins tonometry, Assessment of optic nerve head

Standard automated perimetry

Van Herick’s assessment


Appendix 3


OHT Monitoring Pathway

Patient diagnosed with OHT (no treatment required)




CCT 590 micrometres

IOP 22–32 mmHg Age - any


CCT 555–590 micrometres IOP 22–25 mmHg Age - any

CCT 555-590 micrometres IOP 26–32 mmHg Age > 60


CCT < 555 micrometres IOP 22–25 mmHg Age > 65


CCT < 555 micrometres IOP 26–32 mmHg Age > 80


Referred for monitoring by accredited optometrist at intervals specified by NICE

Examination to include:

  • Suprathreshold perimetry
  • IOP measured by Goldmann applanation tonometry
  • Van Herick’s assessment
  • Slit lamp biomicroscopic examination of the optic nerve





No change in Clinical status


Change in Clinical status



Arrange next appointment as per protocol

Refer to specialist accredited optometrist or hospital clinic


NB: All combinations of CCT, IOP and age not listed above should be referred to the treatment pathway

CCT measurement Gonioscopy assessment Image capture of the optic nerve

Evidence of optic nerve damage and/or visual field changes


Arrange next appointment as per protocol

Refer to consultant ophthalmologist


Appendix 4

Clinical Management Guideline for Glaucoma Repeat Readings (Level 1)

1. Intra-ocular pressure alone (i.e. normal fields and disc appearance)

IOP > 21 mmHg by non contact tonometry at GOS or private sight test and IOP refinement by Goldmann or Perkins tonometry is carried out by the optometrist.


  • All patients with IOP > 31 mmHg should be referred for OHT diagnosis without further IOP refinement.
  • Any patients with IOP ≤ 21 mmHg should be discharged
  • If IOP result is 22 - 31 mmHg, or if there is a difference in IOP of ≥ 5 mmHg between the eyes then Goldmann (or Perkins) is repeated on a separate occasion.

Second repeat of Goldmann or Perkins tonometry (on a separate day)


  • Any patients with IOP ≤ 21 mmHg should be discharged
  • If there is a difference in IOP of ≥ 5 mmHg between the eyes then practitioners may wish to consider whether referral may be appropriate, or whether there is a reasonable explanation (e.g. surgery to one eye)
  • The following patients are referred for OHT diagnosis:
  • 21 mmHg > 24 mmHg > 25 mmHg" src="data:image/png;base64,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" v:shapes="_x0000_s1111">The following patients are referred to the OHT monitoring service if it exists or for OHT diagnosis otherwise:

2. Visual Field alone (i.e. normal IOP and optic disc appearance)

Visual field defect which may be due to Glaucoma found at GOS or private sight test and visual field refinement is carried out by the optometrist on a separate occasion.



  • Field defect consistent on two occasions, patient is referred to consultant ophthalmologist for differential diagnosis or specialist optometrist as per local protocol.
  • Field defect inconsistent or not repeatable patient should be discharged
  1. Optic Disc indications

Suspicious optic nerve head found at GOS or private sight test. Patient is referred to a consultant ophthalmologist or specialist practitioner as per local protocol

  1. Narrow Angle

Suspicious anterior chamber angle found at GOS or private sight test.If suspect narrow angle refer to consultant ophthalmologist if symptoms of sub acute attacks or IOP > 21 mmHg or greater (Van Herick grade 2 or less)


Appendix 5

Clinical Management Guideline for OHT Monitoring (Level 2)

  1. No change in clinical status

No change in clinical status found at OHT monitoring assessment.

  • Next appointment is arranged as per protocol.
  1. Change in clinical status

Change in clinical status found at OHT monitoring assessment.

  • Patient is referred to hospital clinic or specialist optometrist depending on local protocol.

Further diagnostics carried out by specialist optometrist/healthcare professional.

  • Change in clinical status confirmed. Patient is referred to consultant ophthalmologist.
  • No change in clinical status. Patient is referred back to OHT monitoring


Appendix 6

The General Optical Council Core Competencies for Optometry

Core Subject 1:              Communication Skills

The ability to communicate effectively with the patient and with professional colleagues

Core Subject 2:                    Professional Conduct

An understanding of professional conduct and the legal aspects of professional practice

Core Subject 3:              Visual Function

An understanding of and the ability to assess visual function

Core Subject 4:                   Optical Appliances

The ability to prescribe and to dispense appropriate optical appliances

Core Subject 5:                    Ocular Examination

The ability to perform an examination of the eye and related structures

Core Subject 6:                   Ocular Abnormalities

The ability to identify and manage ocular abnormalities Core Subject 7:                                    Contact Lenses

The ability to manage patients with contact lenses Core Subject 8:                                            Binocular Vision

The ability to assess and manage patients with anomalies of binocular vision