Replies to LegCo questions

LCQ5: Orthokeratology contact lens

Following is a question by the Dr Hon Leung Ka-lau and a reply by the Secretary for Food and Health, Dr Ko Wing-man, in the Legislative Council today (July 2):

Question:

It has been reported that Orthokeratology lenses, commonly known as Ortho-Ks, work to reduce myopia on the principle that they exert pressure directly on the corneas, thus changing the corneal curvature, and Ortho-K must be worn continually during sleep for the effect to last. Some optometrists have prescribed Ortho-K for children, claiming that such lens can slow down the progression of myopia. Recently, The Chinese University of Hong Kong published the findings of a research, which pointed out that the risk of contracting microbial keratitis for children using Ortho-K is five times higher than that for ordinary people. The researchers analysed 18 cases of in-patient children diagnosed with microbial keratitis in the Prince of Wales Hospital in the past 10 years, and found that 83% of the cases were related to the use of contact lenses, while 38% involved the use of Ortho-K. In addition, there were 23 cases in the past decade of children being admitted to the Hong Kong Eye Hospital for treatment of serious microbial keratitis caused by the use of Ortho-K. After treatment, all the patients concerned suffered from irreversible visual impairment and could restore only 70% of their eyesight on average, while the severe cases had even resulted in blindness. In this connection, will the Government inform this Council:

(1) whether it knows, in each of the past three years, the number of minors who used Ortho-K, as well as the number of cases in which patients suffering from microbial keratitis sought treatment from public ophthalmology specialist outpatient clinics or were admitted to public hospitals, with a tabulated breakdown by whether the patients were adults and the cause of infection (e.g. use of ordinary contact lenses, Ortho-K or other causes); if it does not know, whether it will conduct a survey in this regard;

(2) under the existing legislation, whether Ortho-K is an optical appliance and whether optometrists may prescribe or provide Ortho-K; if they may, of the provisions concerned; and

(3) given the health risks associated with Ortho-K, whether the authorities have corresponding measures; if they do, of the details; if not, the reasons for that?

Reply:

President,

My reply to various parts of the question is as follows:

(1) According to the statistics of the Hospital Authority (HA), between 2011 and 2013, in-patient admissions due to keratitis, sclera and other disorders of cornea numbered at 578, 605 and 648 respectively. The HA does not maintain a breakdown of the number of patients seeking treatment at ophthalmology specialist out-patient clinics and hospitals due to microbial keratitis.

(2) Orthokeratology contact lens is a type of rigid gas permeable lens which operate by changing the curvature of the cornea, thereby enabling the user to maintain clear vision for a period of time after removing the lens. According to the definition recommended by the Global Harmonization Task Force (GHTF) (Note 1), orthokeratology contact lens is a Class II/III (Note 2) medical device with medium risk. In Australia, Canada, the United Kingdom, the United States and Singapore, orthokeratology contact lens are required to be registered prior to open sale in the market, save for those tailor-made products for designated persons. In addition, the products have to be prescribed by the relevant healthcare professionals, viz ophthalmologists or optometrists.

Currently, there is no specific legislation to regulate the manufacture, import, sale or use of medical devices (including orthokeratology contact lenses) in Hong Kong. Nor are orthokeratology contact lenses included in the list of medical devices covered under the voluntary Medical Device Administrative Control System established by the Department of Health (DH). To protect public health while ensuring the community’s continued access to the benefits of new technologies, the Administration will develop and establish a regulatory framework for governing medical devices. Having regard to the recommendations of the Global Harmonization Task Force and the World Health Organisation, the Administration will adopt a risk-based approach in determining the appropriate level of control for medical devices according to their risks.

In accordance with Item 5 of the Schedule to the Supplementary Medical Professions Ordinance and Section 6 of the Optometrists (Registration and Disciplinary Procedures) Regulation, optometrists whose names have been entered in Part I or Part II of the register and those in Part IV of the register who are allowed to engage in work relating to refraction and contact lenses may prescribe optical appliances including contact lenses. According to the Code of Practice for Registered Optometrists stipulated by the Optometrists Board, when conducting an eye examination and dispensing contact lenses, a registered optometrist has to provide the client with information relating to the care and replacement of contact lenses and make arrangements for continuous aftercare.

(3) To keep our eyes healthy, members of the public should follow the instructions of ophthalmologists or registered optometrists in wearing or taking care of orthokeratology contact lenses and receive regular ocular and optometric check-ups as in the case with users of ordinary contact lenses. Inappropriate cleaning of orthokeratology contact lenses or failure to observe the instructions of ophthalmologists or registered optometrists in properly wearing these lenses may lead to corneal infection or ulcer.

To remind public of the related risks, the Medical Device Control Office under the DH has uploaded onto its website a leaflet on “Know More About Contact Lenses”, which contains information about different types of contact lenses, caring tips and health advice for the public’s reference.

Note 1: The Global Harmonization Task Force (GHTF) was formed in 1992 to harmonise the standards and principles for the regulation of medical devices. In 2011, the GHTF was disbanded, and a new regulator-led group known as the International Medical Device Regulators Forum was formed to build on the work of the GHTF, with a view to accelerating international harmonisation and convergence in the regulation of medical devices.

Note 2: The risk level depends on the duration of use. Contact lenses intended for short-term use (continuously for 60 minutes and up to 30 days) are in Class II, whereas those intended for long-term use (continuously for 30 days or above) are in Class III. For long-term continuous use, the cleaning or maintenance procedures after removal of lenses are considered as part of the continuous use.

Ends/Wednesday, July 2, 2014
Issued at HKT 18:03

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