BCLA CLEAR - Orthokeratology

Abstract

Orthokeratology (ortho-k) is the process of deliberately reshaping the anterior cornea by utilising specialty contact lenses to temporarily and reversibly reduce refractive error after lens removal. Modern ortho-k utilises reverse geometry lens designs, made with highly oxygen permeable rigid materials, worn overnight to reshape the anterior cornea and provide temporary correction of refractive error. More recently, ortho-k has been extensively used to slow the progression of myopia in children.This report reviews the practice of ortho-k, including its history, mechanisms of refractive and ocular changes, current use in the correction of myopia, astigmatism, hyperopia, and presbyopia, and standard of care. Suitable candidates for ortho-k are described, along with the fitting process, factors impacting success, and the potential options for using newer lens designs. Ocular changes associated with ortho-k, such as alterations in corneal thickness, development of microcysts, pigmented arcs, and fibrillary lines are reviewed. The safety of ortho-k is extensively reviewed, along with an overview of non-compliant behaviours and appropriate disinfection regimens. Finally, the role of ortho-k in myopia management for children is discussed in terms of efficacy, safety, and potential mechanisms of myopia control, including the impact of factors such as initial fitting age, baseline refractive error, the role of peripheral defocus, higher order aberrations, pupil size, and treatment zone size.

BCLA CLEAR - Evidence-based contact lens practice

“…For young patients, parental history of myopia increases the risk of myopia developing in the child [92]. For these patients, contact lens fitting can be supplemented with advice and recommendations on myopia management strategies such as myopia control contact lenses, potential pharmaceutical options and environmental considerations, such as time outdoors and time on close work and near digital devices [32] (see CLEAR Orthokeratology Report) [93]. Diabetes has a genetic element [94] and can impact contact lens wear (section 2.4).…”

“…Orthokeratology, scleral lenses and medical use of contact lenses have been covered in accompanying reports, so the following sections focus on soft and rigid corneal lenses (see CLEAR Orthokeratology Report and CLEAR Medical Uses Report) [93,129]. Direct evidence based on a patient's history, refractive error and ocular health that informs lens selection is summarised in Table 3.…”

“…Presbyopia SOFT: ↑ stereopsis if fully corrected vs mono-vision [33] Advise multifocal soft lens Advise rigid corneal lenses ↑ Retention if fully corrected, not mono-vision [24,25] RIGID CORNEAL: ↑ near VA with bifocal and multifocal rigid corneal lenses and ↑ binocular contrast sensitivity [267] Myopia progression SOFT: ↓ Myopia progression with DD concentric rings around CD-zone [268,269], soft bifocal and multifocal designs [270], and Extended Depth Of Focus [271]. Higher near addition ↓ progression [272] Advise on-label soft lens Advise orthokeratology, not rigid corneal lens [93] RIGID CORNEAL: no effect of rigid corneal lens wear on myopia progression in children [273,274] Ocular Surface Health…”

“…Despite these advantages of rigid corneal lenses, only around 10% of wearers use rigid corneal lenses [321], which is most likely due to initial discomfort and adaptation, and the time required to successfully fit and manage rigid corneal lens wearers [276,322]. They are not suitable for part-time wear, but there has been an increase in their use for myopia control using orthokeratology (see CLEAR Orthokeratology Report) [93]. The majority of current rigid corneal lenses are made of silicone-acrylate or fluorosilicone-acrylate, which allow for increased oxygen transmission through the lens material compared to the polymethylmethacrylate (PMMA) rigid lenses used in the past.…”

A Cooperative Management App for Parents with Myopic Children Wearing Orthokeratology Lenses: Mixed Methods Pilot Study

“…Indeed, a higher compliance with the lens wear schedule has been reported to result in greater myopia control efficacy [ 17 ]. Poor compliance with lens hygiene and inadequate follow-up were risk factors for infection [ 18 ]. Parents are primary gatekeepers of their children’s health behaviors [ 19 ]; however, reaching and engaging parents in compliance behaviors can be challenging.…”