Orthokeratology
Orthokeratology is a non-surgical procedure to reshape cornea with a special design rigid gas permeable contact lens while sleeping. By changing the shape of the anterior curvature, light entering the eye can be effectively focused on the retina, without further needs of other correction aims. People can see clearly during daytime but this effect is temporal. Once lens wear is ceased, refractive error will return to its original status. It can correct up to -5.00D shortsightedness. A higher correction may be achieved, depends on the original shape of the cornea. Steeper cornea allows higher degree of flattening. For eyes with moderate astigmatisms, full correction is unlikely.
Orthokeratology is primarily designed to correct refractive error in adult. Because of the high incidence of shortsightedness in Hong Kong children, optometrists apply orthokeratlology to children in order to control the progress of shortsightedness. It is now the most popular method in myopia control in children.
Overnight wear of OK lens is FDA approval in some lens designs. Whether the lens is suitable for overnight wear depends on the oxygen permeability of the lens material. Since many of the OK lenses are make of materials that are proven safe for overnight wear, they are relatively safe to wear even the lenses are not FDA approved.
The main concern in orthokeratology is the risk of bacterial infection. There are incidences of infectious keratitis resulting from gram-positive and gram-negative bacteria and Acanthamoeba, which could be vision-threatening.[1] In order to avoid complications such as infection, proper hygiene is extremely important. Optometrist must closely monitor the patient and refer the patient for medical treatment if complication is identified. Patient is advised to attend scheduled follow-up visit with the optometrist even he/she does not encounter any problems. Also, patients must follow the instruction given by the optometrist. Patients who are interested in OK must be informed about the pros and cons and risks of the treatment. Discuss with the optometrist about your expectation and needs so that he/she can help you to achieve the goal. Successful treatment relies on patient’s compliance and communication. Do talk to your optometrist if you have any questions or problems.
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