August 29, 2019
By Padmaja Sankaridurg B.Opt, MIP, PhD
Brien Holden Vision Institute
It is well known that myopia can be slowed with a number of optical and non-optical interventions that reduce the risk of the eye reaching higher levels of myopia. Efficacy of an optical or non-optical intervention for myopia control is the extent to which myopia progression is slowed in users of myopia control strategies in comparison to wear with a standard single vision spectacle or contact lens. In defining the efficacy, a poor or less than optimal outcome with a treatment may be a result of either a) non-compliance or non-adherence to treatment regimen, or b) true failure.
Compliance or adherence may be defined as the extent to which an individual complies with administering the treatment in accordance with the practitioner’s instructions. Interestingly, it has been said that nearly one-third to one-half fail to comply with general medical advice and prescriptions, with a number of factors such as the individual’s own beliefs, information available to them and personal circumstances playing a role.
What exactly is non- adherence to myopia management strategy?
Non-adherence to myopia management strategy would, in the case of contact lens wear, be failing to wear the lenses for either the required number of hours per day or days per week or interchanging between right and left eyes, or having, for example, blurred vision but failing to replace or have an appropriate correction. In the case of pharmaceutical treatments such as atropine, it could be missing the daily dose, not instilling the drug at the appropriate time of the day or instilling more or less than the required amount. In addition to hastening myopia progression, non-adherence may promote drop out or dissatisfaction, which in turn promotes further non-adherence.
Role of non-adherence in myopia control
Surprisingly, in spite of the critical role played by adherence or lack thereof in defining the efficacy of a myopia control approach, there is little information on the extent to which adherence influences myopia progression. In the recently published LAMP study,1 myopia progression was determined with 0.05%, 0.025% and 0.01% atropine over a 1 year period in comparison to a control placebo group. Participants were asked to administer the drops nightly and it was said that those with 75% compliance rate (i.e., a mean of 5.25 days/week) were considered to have good compliance. However, in spite of the above categorisation, the results were silent on the effect of compliance on myopia progression. Other studies were silent on the treatment protocol.
With respect to contact lenses, in trials conducted by Brien Holden Vision Institute, poor compliance with respect to number of wearing hours per day was found to influence the efficacy outcome with respect to progression of myopia. Those that wore specially designed multifocal contact lenses for longer duration had better outcomes in comparison to those who wore the lenses for ≤ 5 days/week.2 Wearers using myopia control lenses consistently (≥ 6 days per week) had better outcome compared to others ( ≤ 5 days per week). Similarly, in another study involving a myopia control contact lenses (Defocus incorporated soft contact lens – DISC), compliance improved the treatment outcome. In children who wore the DISC lenses for five or more hours/day, progression was 46% less compared to those wearing single vision lenses.3 These data indicate that adherence to lens treatment is important to improve efficacy. In both the contact lens studies that reported on compliance, efforts to characterise patient adherence to treatment regimen were based on self-reported measures that involved questionnaires or diaries. In the study conducted by Brien Holden Vision Institute, no information was provided on the reasons for non-compliance but at 24 months, 38% of the test group were non-adherent in comparison to 22% of the control group wearing single vision lenses.2 Therefore not all of the non-adherence related issues can be attributed to the treatment strategy alone and indicate that there may be factors inherent to lens wear (e.g. comfort) or the individual (unwell, satisfaction, convenience) that may be responsible for the non-adherence. It is possible that the difference between the test and control group may be attributable to the myopia control design such as the strength of the add power, lens design etc.
With pharmaceutical strategies, such as atropine, the treatment is not directly associated with an immediate benefit as opposed to an optical strategy that is linked with vision and therefore, is inherently associated with a higher risk of non-adherence. Furthermore, in young children, the task of instilling eye drops is usually delegated to one or more carers who have other multiple other responsibilities, leading to a higher risk of non-adherence.
In addition, with all treatment strategies especially those that are not linked with an immediate benefit, the risk of non-adherence increases with duration in treatment strategy. Longer the duration, greater the risk of fatigue and therefore non-adherence.
Improving adherence to myopia control treatments
Given the lack of sufficient information on adherence to treatment with myopia control strategies, efforts to reduce non-adherence require to be broad-based (educational) rather than targeted (interventional) approaches. For example, a broad-based approach with involvement and supervision of the child’s practices by the front staff will not only help free valuable time of the practitioner but is likely to enable a more detailed and engaged conversation between the staff and the child to encourage adherence. With such engagements, there is an increased opportunity to detect and diagnose habits and behaviours that may be promoting non-adherence, such as stinging with an eye drop or poor comfort. This would then provide opportunities to have a more targeted approach to manage behaviour relating to non-adherence.
Involving the child in the treatment plan will provide them with a sense of control and independence that they may exert with respect to the wear of the lens. Other broad-based approaches include greater use of digital technology to send information, reminders and electronic diaries.
Padmaja Sankaridurg B.Opt, MIP, PhD, Head, Myopia Program and Global Myopia Centre; Head, Intellectual Property, Conjoint Professor, Brien Holden Vision Institute
- Yam JC, Jiang Y, Tang SM, Law AKP, Chan JJ, Wong E, et al. Low-Concentration Atropine for Myopia Progression (LAMP) Study: A Randomized, Double-Blinded, Placebo-Controlled Trial of 0.05%, 0.025%, and 0.01% Atropine Eye Drops in Myopia Control. Ophthalmology. 2018.
- Sankaridurg P, Bakaraju RC, Naduvilath T, Chen X, Weng R, Tilia D, et al. Myopia control with novel central and peripheral plus contact lenses and extended depth of focus contact lenses: 2 year results from a randomised clinical trial. Ophthalmic & physiological optics : the journal of the British College of Ophthalmic Opticians (Optometrists). 2019; 39:294-307.
- Lam CS, Tang WC, Tse DY, Tang YY, To CH. Defocus Incorporated Soft Contact (DISC) lens slows myopia progression in Hong Kong Chinese schoolchildren: a 2-year randomised clinical trial. The British journal of ophthalmology. 2014; 98:40-5.