Patient retention, drop out, the threat and impact of online supply dominates many of our thoughts regarding contact lenses. Even with an abundance of innovation the market is still relatively stagnant. One area for consideration to help grow your contact lens business and to retain your patients is to offer custom-made products. For some practitioners, the barrier to fitting custom lenses may be a lack of confidence, limited experience, equipment concerns or it not being a focus during their optical training. There may also be the misconception that they are time consuming and not particularly worth the effort. However, fitting custom lenses can elevate your professional image and increase your job satisfaction.

For those who are interested in starting to fit custom lenses or re-visiting them as a patient option, the process can be daunting. This seven-step guide will help you succeed.

1 Patient identification

Our first thoughts on fitting custom lenses may be prompted by a high correction, be it spherical or cylindrical, but this is only part of the opportunity.

There is the ever-increasing category of presbyopes with astigmatism who, while their correction may not be particularly high in any meridian, still have limited options due to the sheer volume of SKUs required to facilitate successful lens wear. In essence, mass-produced lenses may not fulfil their requirements.

The next category are those wearers who are currently using multifocal contact lenses but not completely satisfied with them, ‘functional vision’ may not be enough for them, and a more individualised option may be better. Then, there are those who struggle with haloes or ghosting, therefore using an Extended Depth of Focus design may be needed to solve these issues.

Finally, we have the often overlooked group of patients who have a simple enough correction, which would usually result in them being fitted with a standard off-the-shelf product, but have a smaller or larger corneal diameter than average or their cornea is flatter or steeper than normal.

2 Measurements

As is customary with any contact lens fitting, start with an up-to-date refraction, a corneal assessment, and the biometric measurements of k-readings and HVID (horizontal visible iris diameter). These measurements will contribute to identifying the patient who should be fitted with a custom lens.

A topographer will give more information, such as the amount of flattening towards the periphery of the cornea (eccentricity), but for those without, a keratometer will suffice along with a PD (pupillary distance) rule to take the HVID. If we are fitting a multifocal, then the ocular dominance is required as well.

3 Ordering the lens

We should consider what is the best material for the patient and modality. In addition to those suffering from drier eyes, the patient who requires part-time wear may be best suited to a hydrogel, whereas those who want extensive wear may benefit from a silicon hydrogel. Also, consider the material choice for presbyopic patients who are more inclined to have dry eye symptoms.

At this point, we should have all the information we require to order the lens. Refer to the manufacturer’s fitting guide, which may be supplemented by an online calculator. If you are unsure, they may have a technical support desk to help you with material selection and specifications.

4 Lens collection appointment

Allow a minimum of 20 minutes after insertion to allow the lens to settle, then assess the fit. Only when the eye care professional is content with how the lens fits on the eye should the over-refraction be performed. If fit and vision is satisfactory then proceed with a suitable trial period of wear.

5 Making an adjustment

In an unsatisfactory fit, the beauty of custom lenses means we can adjust and obtain an optimum outcome. Excessive movement can be improved with an increased diameter and/or reduction in the base curve, whereas insufficient movement can be improved with a reduction in diameter and/or increase in base curve.

For guidance, if the lens is rotating more than 20 degrees while the over-refraction is considerably higher than normal expectations, or the visual acuity (VA) does not improve with over-refraction, then the fit is unlikely to be optimal and we will need to reassess base curve and diameter.

6 Seeking support

When faced with an unexpected outcome, such as VA that does not improve with over-refraction, and are unsure how to move forward, manufacturers will be pleased to offer you technical support.

7 Dispense the lenses

When you and the patient are satisfied, then proceed to dispense the revenue lenses, ideally committing the patient to an ongoing service plan. For those unable to offer or join such a plan, then a three-monthly call to remind them to order will ensure good compliance and minimise problems and subsequent drop out.

• Jim Dickson is head of professional affairs UK & Ireland at Mark’ennovy.