The College of Optometrists

Examining patients at risk from glaucoma

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Sub-sections

Key points

  • You must carry out relevant tests when examining a patient who is in the at risk groups for glaucoma.
  • Those with a greater than average risk include certain ethnic groups, patients with first degree relatives with glaucoma and those over 40.
  • You should follow local protocols if you are participating in community services.
  • There is additional guidance on working under the supervision of a consultant ophthalmologist.
  • There is additional guidance on referral of glaucoma suspects and patients with ocular hypertension.

Principles of examining patients at risk from glaucoma

A126
When examining a patient who is in the at risk groups for glaucoma you must carry out relevant tests.41 
A127
Glaucoma can be difficult to detect in the early stages and you should keep up to date with current thinking on the pathophysiology, clinical signs and diagnostic techniques required to detect it. 

Identifying patients at risk from glaucoma

A128
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: 
  1. high IOP
  2. optic disc features suggestive of glaucoma
  3. symptoms of loss of peripheral vision.
A129
Even in the absence of the signs or symptoms in the paragraph above, patients at greater than average risk include those: 
  1. in certain ethnic groups, for example African-Caribbean people
  2. with first degree relatives with glaucoma
  3. over the age of 40. The risk increases with every decade of life thereafter
  4. taking topical or systemic steroids, as they may develop steroid-induced glaucoma.
A130
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. 
A131
The prevalence of angle closure glaucoma is greater than that of open angle glaucoma in people of South or East Asian descent. 

Diagnostic information

A132
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.42
A133
You should be familiar with the risk factors for developing glaucoma. These include:
  1. raised IOP. Where pressures are borderline, you should repeat the test, noting the time of day of each test. NICE recommends43 that patients whose IOP by applanation tonometry is consistently or recurrently greater than 21mmHg:
    • have a formal diagnosis of ocular hypertension by a healthcare practitioner who has appropriate training or qualifications, and
    • are monitored, as they are at greater risk of developing glaucoma
  2. optic disc features suggestive of glaucoma, and
  3. visual field defects suggestive of glaucoma.
A134
Assessment of the central visual field may provide useful diagnostic information and complement the examination of the optic nerve head. This may be particularly important in the diagnosis of normal tension glaucoma. 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. 
A135
Visual field examination may sometimes produce anomalous results; however, you should not underestimate the usefulness of baseline measures and ongoing comparisons. 
A136
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, for example due to pseudoexfoliation syndrome or pigment dispersion syndrome.

Procedures to include in an examination in routine practice

A137
In addition to the procedures for a routine eye examination, you should select additional ones according to the patient’s clinical need. You should normally: 
  1. assess the optic nerve head. This would include assessing the size of the disc, and
  2. measure the IOP, see para A142.
A138
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.
A139
If you suspect the patient has 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). 
A140
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. 

Use of non-contact tonometry

A141
It is good practice to follow up equivocal results from non-contact tonometry with contact applanation tonometry.
A142
If you are using non-contact tonometry, before considering referral you should take four readings per eye and use the mean as the result. In the absence of other signs of glaucoma, you should consider referring the patient for further assessment only when the mean is >21mmHg.  
A143
If the patient has not had non-contact tonometry before and the mean of four readings is >21mmHg you should take a new set of readings for the eye or eyes for which this is the case.44 

Community services

A144
If you are participating in a community service you should follow local protocols where they differ from this guidance. 

Supervision

A145
The College of Optometrists and Royal College of Ophthalmologists have published guidance45 on what is meant by the phrase ‘working under the supervision of a consultant ophthalmologist’ in relation to NICE guidance. 

Referral

A146
The College of Optometrists and Royal College of Ophthalmologists have published guidance on the referral of glaucoma suspects by community optometrists.44 
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