Can we identify those likely to drop-out of orthokeratology?

Paper title: Analysis of the Reasons for the Discontinuation of Orthokeratology Lens Use: A 4-Year Retrospective Study

Authors: Lina Ma (1,2), Man Xu (1,2), Jing Wang (1), Xiaoguang Niu (1,2)

1. Aier Eye Hospital of Wuhan University, Wuhan, China
2. Hanyang Aier Eye Hospital, Wuhan, China.

Date: Aug 2022

Reference:  Ma L, Xu M, Wang J, Niu X. Analysis of the Reasons for the Discontinuation of Orthokeratology Lens Use: A 4-Year Retrospective Study. Eye Contact Lens. 2022 Aug 1;48(8):335-339

[Link to open access paper]

A recent study in China found that myopic prevalence was nearly 60%.¹ Concerns over high myopia levels in children and teenagers has increased awareness of the importance of controlling and preventing myopia.² Although orthokeratology (ortho-k) has become a popular treatment option in China for correcting and controlling myopia, some patients do discontinue wear.

This retrospective study investigated reasons for discontinuing wear by examining the files of 2,499 patients fitted for ortho-k between 2017 and 2020 at Hanyang Aier Eye Hospital, Hubei Province, China.

The patients were aged between 8 and 18yrs. All had healthy eyes with myopic refractive error between -0.75D and -6.00D and astigmatism no more than -1.50D.

The children had a median age of 11yrs and mean refraction of -3.14D when fitted, and wore the lenses for approx. 24mths. Children who discontinued wear during the adaptation period (due to unsure parents or discomfort) were not included in the review.

• There were 50 patients who discontinued wear, aged between 10 and 17yrs. Half of these patients gave the reasons given for stopping wear as either a short sleep time (18%), economic factors (16%) or a poor myopia control result (10%).
• The longer the lenses were worn, the number of patients discontinuing wear decreased.
• When the reasons for stopping wear were compared by age group, it was found that the primary reason was an 'inability to use the lenses for various reasons' for 60% of under 14yrs olds and 40% of those over 14yrs. Other reasons such as economic factors, poor myopia control or short sleep time were not statistically different by age group.
• Children who did not adhere to treatment for other reasons such as foreign body feelings had slightly lower levels of myopia. The discontinuation rate was lower for those with myopia between -3 and -6D than for those with myopia up to -3D.

Two of the three patients who developed corneal infiltrates were under 14yrs but none of them stopped wear due to this.

Thirty patients who stopped wear had completed their ortho-k myopia control treatment, to then undergo refractive surgery once they reached adulthood.

The discontinuation rate for ortho-K was 2%, and the most common reason was not adhering to lens wear. This appears to be much lower than that found in soft contact lenses, where the most common reason was discomfort.³ 

• There were 3 patients with corneal infiltrates (an incidence of 0.1%). Wearing the lenses for longer than 10hrs per night was found to be a common risk factor. These did not lead to discontinuation.
• 5 wearers in this study found they had a poor myopia control effect from ortho-k. Although this is a small number in the study population, it could be representative of many more wearers in the wider population.

It may be possible to identify which children might be more likely to discontinue wear:

• Those with shorter sleep times
• Lower myopic correction, where children with refractive errors between -3 and -6D were more likely to continue wear, presumably more motivated to continue with myopia correction and control benefits
• Those not following prescribed wear times for adaptation.

Patients and parents can be reassured that discomfort symptoms can be common initially but will improve during the first 4 weeks. Adherence to the adaptation process and lens care compliance is important to gain the maximum myopia correction effect and manage risk.

1. For wearers over 14yrs old, a common reason for stopping wear was shorter sleep time. The short sleep time may be associated with increasing schoolwork with age and time spent on close work. With reduced sleep time, the myopia control effect from ortho-k could be reduced, and myopia has also been associated with sleep duration.^4,5,6 The authors have suggested that since 73% of Chinese students do not sleep long enough, educational expectations could move away from being exam-orientated to improve overall health and development.
2. Economic factors were a reason for some to discontinue ortho-k: ongoing costs such as attending appointments, lens replacements and solutions could make ortho-k a large family expenditure. Addressing costs as well as increasing public awareness of myopia could support these issues.
3. This study analysed reasons for discontinuing wear after 4yrs. If the study was repeated over a longer period of time, there may be different reasons for stopping wear.

Title: Analysis of the Reasons for the Discontinuation of Orthokeratology Lens Use: A 4-Year Retrospective Study

Authors: Lina Ma, Man Xu, Jing Wang, Xiaoguang Niu

Purpose: Although orthokeratology has a positive effect on myopia control, some patients discontinue orthokeratology lens use. This study analyzed the data of all patients who had been fitted with an orthokeratology lens in the past 4 years and the reasons for discontinued lens use, with the aim of improving the prevention and control of myopia

Methods: This retrospective study analyzed the data of patients, aged 8 to 18 years, fitted with orthokeratology lenses from 2017 to 2020. The ametropic spherical lens powers ranged from 26.00D to 20.75 D, and the cylindrical lens powers were all more than 21.50 D. The reasons for discontinuation of lens wear were analyzed and compared. The period of lens wear (median [range]) was 24 (13.5-34.5) months.

Results: A total of 2,499 patients' files were retrieved. The duration of lens wear was 24 (13.5-34.5) months. A total of 50 patients discontinued lens use, including 25 patients (50.0%) who could not adhere to lens use for various reasons, nine patients (18.0%) with a short sleep time, eight patients (16.0%) with economic difficulties, and five patients (10.0%) who experienced a poor effect after wearing the lenses. Corneal infiltrates affected lens use in three patients (6.0%). In addition, 30 patients underwent surgical correction when they reached adulthood.

Conclusions: Although orthokeratology lenses are effective and safe, there are still a small number of patients who discontinued lens use for various reasons. Adherence and precautions should be emphasized during the process.

[Link to open access paper]