Orthokeratology (Ortho-k)

In a territory where 70% of the young adult population is myopic (short-sighted) and where myopia progression in young children is 0.50 D per year, it is not hard to imagine the tremendous attention and interest procedures for myopia control or reduction have aroused. There have been recent worrying reports of corneal ulcers in children wearing ortho-k lenses and the public has justifiable concerns in this regard. In one of our research studies, we found poor compliance in patients under ortho-k therapy. To minimize risk of complications, regular check up, hygiene and compliance is essential.

Ortho-k can be defined as a technique where the cornea is progressively reshaped using specially made contact lenses, thereby reducing myopia. New technology has significantly accelerated the reshaping of the cornea. However, unlike LASIK, ortho-k does not lead to permanent change. Ortho-k is a treatment for reducing myopia, and it is NOT a cure. The myopia reduction effect is only temporary and the patient needs to continue to wear the lenses to maintain the effect. Our research study on myopia control with ortho-k lenses has shown that eyeball elongation in myopic children was about half the elongation observed in myopic children wearing spectacles. Effectively, this means that the progression in myopia in children undergoing ortho-k was slower by about 50% when compared to children wearing spectacles.

Ortho-k may be prescribed as day wear or overnight wear regimes. In day wear, the patient needs to wear the lenses for a number of hours and then, if successful, have clear vision for the rest of the day. With overnight wear, the inconvenience of wearing rigid lenses during daytime is removed, allowing patients to see clearly without contact lenses or glasses during the day. The amount of myopic reduction is also higher than day wear. Overnight wear is therefore more attractive to patients and is the main ortho-k regime used in Hong Kong. Overnight wear, however, has greater risk than day time wear, and requires much higher professional skills and an uncompromising ethical approach. Good hygiene and patient compliance are also vital.

Research into the safety of ortho-k is essential and urgent because the demand for myopic reduction is on the increase and because some practitioners may use more aggressive approach to reduce myopia faster. The School of Optometry (SO) of The Hong Kong Polytechnic University hosts the only department in the Hong Kong Special Administrative Region (HKSAR) offering contact lens education. We are concerned about the safe and healthy practice of ortho-k and the University supports research and continuing professional education in ortho-k in Hong Kong.