- You must carry out relevant tests when examining a patient who is in an at-risk group for glaucoma.
- Those with a greater than average risk include certain ethnic groups, patients with first degree relatives with glaucoma and those over 40.
- In England, patients whose IOP is 24mmHg or greater should be treated.
- You should follow local protocols if you are participating in community services.
A223
This Guidance does not change what you must do under the law.
A224
When examining a patient who is in an at-risk group for glaucoma, you must carry out relevant tests.87 Guidance varies across the UK.88, 89, 90 You should be familiar with the relevant guidance and the thresholds at which further tests should be undertaken. If local protocols apply you should comply with these.
A225
Glaucoma can be difficult to detect in the early stages and you should stay up-to-date with current thinking on the pathophysiology, clinical signs and diagnostic techniques required to detect it.
References
87 Sight Testing (Examination and Prescription)(No 2) Regulations 1989 para 3(1)(a) [Accessed 19 Nov 2020]88 National Institute for Health and Care Excellence (2017) Glaucoma: diagnosis and management [Accessed 19 Nov 2020]
89 The College of Optometrists (2017), NICE Guideline – Glaucoma diagnosis and management (update) [Accessed 25 July 2019]
90 Scottish Intercollegiate Guidelines Network (2015) Glaucoma Referral and Safe Discharge [Accessed 19 Nov 2020]
A226
You will identify the majority of patients who are at risk from primary open angle glaucoma during a routine eye examination. They are principally patients with one or more of the following:
- optic disc features suggestive of glaucoma
- loss of peripheral vision
- high IOP.
A227
Even in the absence of the signs or symptoms in the paragraph above, patients at greater than average risk of primary open angle glaucoma include those:91
- in certain ethnic groups, for example African-Caribbean people
- with first degree relatives with glaucoma
- over the age of 40. The risk increases with every decade of life thereafter
- with thinner corneas
- with myopia (myopia >6D is associated with an increased risk)
- with diabetes
- with systemic hypertension
- taking topical or systemic steroids, as they may develop steroid-induced glaucoma.
A228
The signs of asymptomatic primary angle closure glaucoma are almost identical to those of primary open angle glaucoma with the exception that the anterior chamber angle is capable of closure.
A229
The prevalence of angle closure glaucoma is greater than that of open angle glaucoma in people of South or East Asian descent.
References
91 College of Optometrists (2018) Clinical Management Guidelines Primary Open Angle Glaucoma [Accessed 19 Nov 2020]A230
You should be familiar with signs and symptoms of primary open angle glaucoma, including that around 40% of patients with glaucoma have IOP below 21mmHg.92
A231
Assessment of the central visual field may provide useful diagnostic information and complement the examination of the optic nerve head. Visual field findings should fit with optic disc findings. For example, if examination shows an inferior optic disc notch, you would expect to see a superior field defect.
A232
Visual field examination may sometimes produce anomalous results; however, you should not underestimate the usefulness of baseline measures and ongoing comparisons.
A233
Patients with raised IOP are at increased risk of developing glaucoma. Where pressures are borderline, you should repeat the test, noting the time of day of each test. NICE recommends93 that patients whose IOP by contact applanation tonometry is 24mmHg or higher should be:
- formally diagnosed with ocular hypertension by a healthcare practitioner who has appropriate training or qualifications
- treated, as they are at greater risk of developing glaucoma
A234
You should be aware of the signs and symptoms of other forms of glaucoma, such as acute or sub-acute narrow angle glaucoma or secondary glaucoma, due, for example, to pseudoexfoliation syndrome or pigment dispersion syndrome.
References
92 Shah R, Wormald R (2011) Glaucoma. BMJ Clinical Evidence (online) [Accessed 19 Nov 2020]93 National Institute for Health and Care Excellence (2017) Glaucoma: diagnosis and management NG81 [Accessed 19 Nov 2020]
A235
You should select additional procedures to those in the routine eye examination, according to the patient’s clinical need. You should normally:
- assess the optic nerve head. This would include assessing the size of the disc
- measure the IOP. See paragraph A239.
A236
If a patient refuses to consent to tonometry after you have explained the reason for this procedure, you should record the patient’s reason for refusal. You should use your professional judgement to decide how best to manage the patient.
A237
The examination may also include an assessment of the central visual field using perimetry with threshold control. Where necessary, you should repeat visual field assessment to obtain a meaningful result.
A238
If the patient is at risk from glaucoma, you should assess the anterior eye and angle, for example by slit lamp – Van Herick technique. You should also look for signs of pigment dispersion syndrome (PDS) and pseudoexfoliation (PEX).
A239
It is good practice to follow up equivocal results from non-contact tonometry with contact applanation tonometry. If you are using non-contact tonometry, before considering referral you should take four readings per eye. In England, Wales and Northern Ireland, in the absence of other signs of glaucoma, you should refer the patient for further assessment only when the mean of the IOP readings is 24mmHg or above. You should advise people with IOP below 24mmHg to continue with their routine eye examinations. In Scotland you should follow SIGN guidelines.
A240
In England, unless clinical circumstances indicate that urgent or emergency referral is indicated, patients should have referral filtering before they are referred to the HES. For these non-urgent patients, you should only refer without referral filtering if there are no such local arrangements. Referral filtering is where the patient has additional tests done. These may be repeat measures, referral refinement or enhanced case finding.93 In Scotland you should follow SIGN guidelines.
References
93 National Institute for Health and Care Excellence (2017) Glaucoma: diagnosis and management NG81 [Accessed 19 Nov 2020]A241
If you are participating in a community service you should follow local protocols where they differ from this guidance.
Blakeney S (2017). Glaucoma and ocular hypertension – NICE guidelines, past and present Optometry in Practice 18(4):218-224 [Accessed 19 Nov 2020]
The College of Optometrists. Clinical Management Guidelines [Accessed 19 Nov 2020]
College of Optometrists higher qualifications in glaucoma [Accessed19 Nov 2020]
Eye Health Examination Wales clinical manual with protocols for optometrists, ophthalmic medical practitioners (OMPs) and contractors (2018) [Accessed 19 Nov 2020]
International Glaucoma Association [Accessed 19 Nov 2020]
National Institute for Health and Care Excellence (2017) NG81: Glaucoma: diagnosis and management [Accessed 19 Nov 2020]
Royal College of Ophthalmologists (2016) Commissioning Guide: Glaucoma [Accessed 25 Nov 2020]
Scottish Intercollegiate Guidelines Network (2015). SIGN 144. Glaucoma referral and safe discharge [Accessed 25 Nov 2020]
