Fitting Orthokeratology Lenses
Fitting orthokeratology (ortho-K) lenses is a highly specialised procedure that requires precision, advanced diagnostic technology, and expert clinical judgment. The process is tailored to each individual because ortho-K lenses reshape the cornea overnight, and the effectiveness and safety of treatment depends on achieving an optimal lens design and fit.
The fitting process begins with a comprehensive eye examination, including assessment of refractive error (e.g. myopia, astigmatism), ocular health, and tear film stability. A detailed patient history is taken to determine suitability, particularly for children undergoing myopia control or adults seeking daytime freedom from glasses and contact lenses.
The most critical component of the assessment is corneal topography, which maps thousands of data points across the corneal surface. This allows the practitioner to evaluate corneal curvature, symmetry, and shape—information essential for designing the customised ortho-K lens.
Using topography data, the practitioner orders customised lenses that are accurate to with 0.01mm. This lens is placed on the eye to evaluate lens centration, movement, and fluorescein patterns—which reveals how the lens interacts with the corneal surface. These patterns indicate whether the lens provides adequate central treatment zone alignment, appropriate mid-peripheral clearance, and stable positioning during sleep.
Patients are then instructed on insertion, removal, and hygiene, since safe handling is crucial for preventing infection. The first overnight trial marks the beginning of corneal reshaping. The following day, the practitioner performs a follow-up examination and repeats corneal topography to compare pre-wear and post-wear maps. These results guide any necessary lens adjustments.
Over the next three months, additional follow-ups fine-tune the lens design until the corneal reshaping is consistent, central, and produces clear daytime vision. Once the ideal fit is achieved, patients typically require regular reviews every 6 to 12 months to monitor corneal health and ensure long-term success.
Through customisation, careful monitoring, and ongoing assessment, the ortho-K fitting process provides safe, effective vision correction and highly successful myopia control for children and adults.
