This article was originally published in a sponsored newsletter.

Orthokeratology has been established as a safe method to manage myopia. However, as prescribers, we need to remain diligent in monitoring our patients’ corneal health. Corneal staining and other findings can show up for various reasons during the ortho-k process. Understanding why we see certain corneal changes throughout treatment can improve our ability to assess lens fits on-eye and promote long-term corneal health in our ortho-k lens wearers. 

Corneal Staining

When we see epithelial disruption on the central cornea after lens wear, the sagittal depth is likely too shallow and the lens is bearing on the corneal apex. When assessing the lens on-eye, the area of staining will fall under when the lens “hinges” on the cornea, and minimal sodium fluorescein will exchange over the area on blink. The remedy to central staining is to cease lens wear until the cornea heals, and to refit the lens with a greater sagittal depth.

Corneal staining can also occur when the lens is too deep or too tight in the peripheral curves. A tight ortho-k lens will trap stagnant tears or possibly soaking solution under the optical zone and create a toxic response in the corneal epithelium. Corneal impression rings may also be noted, and patients often complain of difficulty or pain with lens removal in the morning. This finding typically covers a good portion of the cornea under the optical zone of the lens, whereas central staining from a shallow ortho-k lens is localized and concentrated. Opening the midperipheral lens’ curves will facilitate tear exchange as well as improve the cornea-lens fitting relationship and patient discomfort.

Epithelial Heaping

When an ortho-k lens is too deep for the cornea shape, the hydraulic forces of the tear film under the lens can cause heaps of epithelium in the central cornea. With white light under a slit lamp, epithelial heaping can look like central staining. However, when visualized with sodium fluorescein, negative corneal staining will be observed, usually accompanied with a central island on topography. Reassessing the sagittal depth of the lens will show apical clearance and a lack of the classic ortho-k central bullseye.

New Findings with Old Lenses

Occasionally, patients will present to the clinic with irritated eyes or reduced vision after a long period of ortho-k success. The topography will look distorted, vision may be blurred, and patients may report reduced lens tolerance. Rather than assuming the eye has changed and proceeding with an adjusted lens order, consider deep cleaning the lens with a protein and deposit remover and reassessing vision and comfort in a couple weeks. Biofilm and deposits can cause an ortho-k lens to bind to the cornea or they can create surface inflammation and corneal staining when the lens fit well previously.

As with any specialty lens, a great tool for navigating unwanted corneal findings is a slit lamp camera. Corneal photos under white and cobalt-blue light with and without the lens can assist you and your lens consultant with making the recommended adjustments in ortho-k lens management. With a little practice, these findings can be identified and managed early, protecting corneal health and improving the ortho-k experience for patients.