Considering even emmetropic eyes elongate, what are the limits of myopia control efficacy? This novel analysis explores the absolute axial elongation of treated and untreated myopes in the MiSight 3-year clinical trial in comparison to previously published models of myopic and emmetropic eye growth. The results indicate a potential limit to the short-term percentage efficacy of myopia control treatments.
What can you expert in short-term fitting, vision, handling and comfort outcomes in children through to long term outcomes in myopia control, vision and ocular health? This article provides the scientific and clinical basis to get started and continue successfully fitting MiSight 1 day for myopic children.
Total spherical-like higher-order aberrations (HOA) increased by more than double in the distance-centred +2.50 Add compared to +1.50 Add, with total coma-like HOA increasing further. Since orthokeratology studies have reported an association between more change in HOAs and better myopia control efficacy, this could indicate a mechanism of action in multifocal contact lens myopia control.
A sample of slow and fast progressors in prior 24 month orthokeratology clinical trials were found to have the same baseline refraction and axial length. The slow progressors were older, and showed 0.5mm smaller treatment zone diameters (TZDs), but no difference in induced peripheral myopic shift. There was also no direct correlation between TZD and axial elongation, indicating an intriguing but not yet defined relationship.
Young adults fit with CooperVision Proclear multifocal contact lenses showed no loss of peripheral vision detection ability compared to single vision contact lenses. The near add was chosen to generate +0.50 or +1.00 of peripheral blur, confirmed by peripheral refraction measurement. This is a positive indication that fitting MFCLs in young wearers doesn’t impact peripheral visual performance.
After the 3-year MiSight 1 day clinical trial, the control group children were switched to MiSight. A ‘virtual control group’ mathematical model, previously published, was utilized to demonstrate a continued myopia control effect across six years, plus effectiveness of treatment for children who commenced wear at age 11-15 years.
The BLINK study found that +2.50 Add centre-distance multifocal contact lenses (MFCLs) slowed myopia progression but the +1.50 Add didn’t. Further analysis indicates that increased peripheral defocus created by the +2.50 Add only accounted for around 15% of the myopia control effect, indicating other mechanisms are involved.