You must only prescribe or recommend a change of spectacles when it is in the patient’s best interests to do so.¹²⁵ NHS Counter Fraud Services have a remit to pursue cases where sight tests are carried out at inappropriate intervals and spectacles are supplied when they may not be clinically necessary.^{126, 127, 128}

You must make a professional judgement about whether a patient would benefit from a prescription for a low refractive error, for example small hypermetropic corrections in children. See section on Examining and managing patients with an anomaly of binocular vision.

If you supply prescriptions of less than +0.75 R&L, to children for example, you must: 

1. be sure of the clinical need for the spectacles
2. be able to explain the reason for prescribing them
3. keep a record of the reason and any advice given.

If you make a small change to an existing prescription you must: 

1. be clear about the benefit of the change
2. keep a record of the reason and any advice given.

If you are unable to provide the justifications in the above paragraphs, the Counter Fraud Services may consider you have been overprescribing and take action against you. See section on Information for small prescriptions, below.

The following examples should assist you in deciding whether or not a prescription is likely to be beneficial:

1. plus prescriptions of less than +0.75DS (binocularly) are unlikely to be of benefit to children under 16, unless there are clinical indications for giving such a low prescription or there are persuasive psychological reasons for doing so. Factors to consider include:
   • a particularly low amplitude of accommodation
   • ocular muscle balance problems at distance and/or near
   • low fusional reserves
   • poor health of a patient resulting in the need to correct low degrees of ametropia. If this is likely to be of short duration, you should consider whether the prescription will still be necessary when the patient’s health improves
2. if a low prescription is found in one eye only, you should consider the points above and, in particular, whether the patient will benefit from such a low prescription in one eye only
3. if you decide to prescribe a small prism (less than 1 prism horizontally or 0.5 prism vertically), you should take into account all the clinical factors including the patient’s ocular muscle status, and whether the use of the prism is appropriate. You should consider any presenting symptoms
4. a small change in prescription (e.g. +0.25DS extra in both eyes) may be justifiable in some circumstances but not in others. For example, changing a +1.00DS reading prescription to a +1.25DS may well have significant benefits to the patient whereas changing a +8.00DS to +8.25DS is likely to have much less effect
5. you should consider factors such as the patient’s visual acuity and ocular muscle balance. A small prescription change in a patient with poor visual acuity may not be as significant as one in a patient with good visual acuity
6. in very high powers you should be aware that the manufacturing tolerances and/or the effect of very small changes in back vertex distance make 0.25DS changes meaningless.