Orthokeratology - Uses, Technique, and Disadvantages

Introduction

Contact lenses and power glasses are often used to rectify errors in vision. Alteration in the curvature of the lens and the cornea reflect various ocular condition that demands corrective treatment to enhance the person's vision. Orthokeratology is a newer advancement that aids in correcting and restoring vision in individuals with remarkable visual defects. It is gaining wide acceptance and popularity. Patient cooperation entails the success of the treatment intervention.

What Is Orthokeratology?

Orthokeratology is an innovative strategy to deal with errors in the vision. Ortho-k is the popularly used synonym for orthokeratology. Orthokeratology treatment is delivered with the help of specially fabricated lenses. This technique eliminates the need for extensive, exploratory surgical procedures to enhance vision. The patients are instructed to wear specially fabricated, custom-made contact lenses, preferably at bedtime. These lenses modify and alter the shape of the thin cornea (clear eye layer that guides light) and gradually rectify errors in vision. An abrupt stoppage of wearing the lens without the concerned doctor's advice can immediately reverse back the error. The retention of visual improvement requires strict adherence to the doctor's instructions and guidelines.

What Are the Conditions for Which Orthokeratology Is Advised?

Orthokeratology is extensively advised for dealing with the ocular condition called nearsightedness (compromised far vision). In addition, it can also tackle other visual defects like farsightedness (compromised near vision), presbyopia (age-induced near vision loss), and astigmatism (abnormally arched cornea). However, the effectiveness of orthokeratology treatment is guaranteed when it is advised for nearsightedness rectification. It is effective for both younger and elderly populations. Children detected with nearsightedness can be promptly managed with orthokeratology technique, thereby safeguarding vision and preventing the development of squint.

What Is Nearsightedness?

Nearsightedness is a popular ocular defect where the person experiences trouble seeing objects at a distance. At the same time, the person can comfortably see closer objects. Far vision appears hazy, unclear, and blurred, while near vision remains unaffected. The synonym myopia widely knows it. For an image to be properly seen, the light reflected from the object should reach the inner retinal layer (light reactive). Specific cells in the retinal layer recognize and perceives the light, which is then transformed into another form of energy - an electrical signal. The electrical impulse is then taken up by the specific brain area, which imparts meaning to the signals, and that is how vision is enabled. In nearsightedness patients, there is an abnormal arching of the cornea. This abnormality forces the light to concentrate prematurely at a different location, and the light fails to reach the retina, eventually precipitating nearsightedness. It entails corrective procedures to restore the far vision. Corrective power eyeglasses, ortho-k, and contact lenses are advised to counterbalance the abnormal corneal curve. Surgical correction of the curvature is also an effective remedial treatment strategy.

What Is the Mechanism of Orthokeratology?

• Orthokeratology's mechanism and working principle are similar to that of dental braces. Orthokeratology works by altering the arching of the cornea. The cornea is delicate, dome-shaped with an inward curvature, and pliable, potentially acting as an interface between the external environment and the inner eye.

• Corneal curvature facilitates the bending of light rays and guides the light into the retina. Abnormalities in the curvature angle, either excess or inadequate arching, project in the form of ocular defects, like nearsightedness.

• The concerned specialist computes the patient's corneal curvature using corneal topography in this technique. Considering the results of corneal topography, the lens is designed accordingly; hence, in orthokeratology, the lenses are individualized and structured explicitly for that particular person.

• These lenses are structured so that the regular wearing of the lens gradually alters the arching of the pliable cornea. It compresses the central point of the cornea, thereby modifying the corneal curvature.

• It aids in guiding the light rays into the retina and decelerates the advancement of visual error. Eventually establishes normal curvature of the cornea and enhances vision.

• It is a promising treatment intervention for those patients who prefer to have neither complex surgeries nor power glasses. The rectification usually happens in a couple of weeks following the nightwear of ortho-k lenses.

• Orthokeratology employs a series of custom-made lenses in succession (one after another) until the desired correction is obtained. After that, the patients are advised to continue with the same lens for a significant period to ensure curvature retention.

What Are the Problems Associated With Orthokeratology?

Though orthokeratology is a minimally invasive procedure, it potentially carries certain risks. Some of the frequently encountered troubles associated with orthokeratology include the following:

• Infections: It involves the usage of contact lenses throughout the treatment period with frequent insertion and removal of the lens. Frequent wearing of contact lenses holds the risk of various microbial infections in the eyes. Inserting the lens with an unclean eye can precipitate bacterial infections.

• Expensive: Orthokeratology treatment is expensive and only affordable for some economic classes.

• Technique Sensitive: Orthokeratology treatment can be done by ophthalmologists with special expertise in this technique and require special machines and instruments.

• Discomfort: Most patients encounter irritation and trouble sleeping with the lens on. However, over time the patient will get accustomed to it.

• Patient Cooperation: The patients are instructed to wear the lens daily without fail; hence, the effectiveness and success of the treatment depend upon the patients. Insertion and removal of lens pose challenges initially.

• Relapse: Once the patient stops wearing the lens, there are chances that the gained correction can be lost. Corneal correction induced by ortho-k lenses is not permanent and requires proper attention to retain the results.

Conclusion

Orthokeratology is an ocular treatment intervention extensively employed to tackle defective corneal curvature. The patients are given sets of lenses to wear, specifically at night while sleeping, which can alter the corneal arch and improve eyesight. It not only enhances vision but also checks the progression of ocular defects. The outcome of this intervention is more or less patient-dependent, and it entails strict adherence to the treatment regime. However, it is a promising alternative for complex eye surgeries. Trained ophthalmologists perform orthokeratology treatment after assessing the patient's corneal arching. Prompt follow-up with the concerned doctor aids in retaining the corneal corrections for longer.