Spectacle Dispensing: Issues to Avoid

Introduction

An exploration of evidence into spectacle dispensing reveals there is a lack of research in areas of this field. Although much is known about light and lenses with some fantastic texts about how this relates to the practicalities of spectacle dispensing, little has been conducted to evidence the patient’s experience¹. 

The UK Optical Consumer Complaints service has shown common complaints in the optical sector stem from:

• “Non tolerance of lenses particularly where the prescription and dispense are provided by different practices
• Varifocal lens adaptation”²

Another source of information is an international systematic review exploring spectacle non-tolerance by Bist et al. (2021)³. Though refraction issues were found to be the main culprit of spectacle non-tolerance (47.4%), dispensing issues came third (13.5%), behind communication (16.3%). The top three causes were found to be:

• Lens centration
• Inappropriate type of multifocal or SV lenses
• Errors in frame adjustments

This study doesn’t inform who conducted the dispensing, so there is a need to consider the competence and appropriate training of the individuals undertaking this task, which may vary depending on the regulations in place. What can sometimes be forgotten is that although an essential requirement, a prescription does not equal a usable pair of spectacles. A good dispense comes from the interpretation of the prescription, thorough communication with the patient, appropriate recommendations and accurate measurements. Here are some top tips in dispensing to avoid complaints and non-tolerance:

A good fitting frame

The frame needs to fit the patient so that the weight is evenly distributed on the bearing surfaces of the nose and the ears – the 3-point fitting triangle. This starts with the nose and where the bearing surface (the crest) is in relation to the patient’s eyes. Is it high or low? This helps to consider where the bridge of the frame will sit – is a frame with a high bridge needed or one where it is placed lower in relation to the top of the lenses? Will a frame with pads on arms be better to help positioning? How much does the nose broaden out? There is a need to consider the patient’s head and temple width as this affects the fit of the frame where it connects with the skull – too small and the sides will be pushed out and the frame squeezed forward. Ideally the patient’s pupils want to be central in frame both vertically and horizontally, though this is unlikely to be exact it helps minimize decentration. For hyperopes this allows the smallest suitable frame possible to be selected, enabling thinner lenses. For myopias it evens the lens edge thickness out around the frame.

Fit the frame before taking any lens measurements

This can’t be emphasized enough; the only exception is using pupillary distance to assist in frame choice. If the frame is not fitted, any vertical centration for aspheric lenses or varifocals may be incorrect on collection. If the pantoscopic tilt is adjusted at collection, it will affect the vertical centration – an increase of 2 degrees would require the vertical centres to be lowered by 1mm⁴. 

Monocular centration

Every single time! There is a need to be fully aligned with the patient both vertically and horizontally or the measurements will not be accurate. Anything other than distance centres need to be taken at the appropriate focal distance to allow for the convergence. 

Vertical positioning of the eye

The eyes rotate up as well as down. Be mindful of any requirements for minimum depth e.g. varifocals and myopia management lenses which may require minimum distances both above and below the pupil centre. 

The 3-way handover

The optometrist often does not have time available to undertake all the communication necessary to uncover the patient’s lifestyle needs. The patient has often developed clinical trust in them which they may not have with the dispensing optician (DO), who may be more viewed as a retailer³. 

"A 3-way handover enables the optometrist to transfer the trust created in the eye examination over to the dispensing optician, by communicating their professional skills. The dispensing optician is able to ask any clarifying questions and the patient has an opportunity to ask any questions they may not have previously considered."

Visual task analysis

If the patient’s needs are not uncovered, they are unlikely to be satisfied. Everyone is unique and there is a need to understand what the person does and what is important to them. This information then needs to be considered in the context of their refractive requirements. Asking open questions allows the patient to start describing their day-to-day activities from their personal perspective, which is more likely to uncover what they feel is important to their functioning, e.g.: 

• ‘What do you do day-to-day in your work?
• ‘What does that entail?’
• ‘What do you like to do when you’re not at work/in your spare time?'

Once there is a general understanding more specific questions can uncover the nuances e.g.: 

• ‘How often do you do need to do that?’
• ‘What distance from you is your screen(s)?’
• ‘Do you frequently have to get up from your desk/look over your monitor?’

Informed choice:

Once a visual task analysis is complete a recommendation of which frame and lens type(s) are most likely to satisfy the patients visual and lifestyle requirements can be offered. The ‘pros and cons’ of the options available should be fully discussed, including that more than one solution may be the best option e.g. varifocals and a near pair, additional safety specs, contact lenses, occupational lenses, sunspecs etc. If any Rx modification is required for occupational purposes, it is good practice to show the patient in a trial frame so they can experience the correction. 

Summary

It is essential that spectacle dispensing is undertaken by a person appropriately trained to perform the requirements. All patients are unique in the combination of their facial characteristics, their refractive requirements and their task and lifestyle needs. These must be accurately taken into consideration in combination to provide visual solutions that will satisfy the patient’s needs. 

References

1.    Morgan PB. et al. BCLA CLEAR Presbyopia: Management with contact lenses and spectacles. Cont Lens Anterior Eye. 2024 Apr 16:102158. doi: 10.1016/j.clae.2024.102158. Epub ahead of print. PMID: 38631935

2.    Optical Consumer Complaints Service (OCCS). FAQs for Practitioners. Available at: https://www.opticalcomplaints.co.uk/insights/faqs-practitioners/ [Accessed 16th June 2024]

3.    Bist J, Kaphle D, Marasini S & Kandel H. Spectacle non-tolerance in clinical practice – a systematic review with meta-analysis. Ophthalmic Physiol Opt. 2021;41(3):610-22

4.    Tunnacliffe AH. Essentials of dispensing. Association of British Dispensing Opticians. 2003. Godmerham, UK

5.    Powell S. The how-to of handovers. Optometry Today [Online] 14th April 2023. Available at: https://www.aop.org.uk/ot/life-in-practice/business-management/2023/04/14/the-how-to-of-handovers