Practice of orthokeratology by a group of contact lens practitioners in Hong Kong : Part I. General overview

Purpose: To describe orthokeratology (ortho-k) as practised by a number of practitioners in Hong Kong. Methods: Twelve optometrists who had been practising ortho-k for between 2.5 and four years were interviewed in the period 1 March to 30 June 2001. Results: The number of ortho-k cases seen by each practitioner ranged from 50 to 800, and the main reason for fitting was myopia control in children. All practitioners were using advanced ortho-k lens designs and most recommended night therapy. In general, patients were accepted if they had less than five dioptres of myopia; one or two lenses were required for a myopia reduction of four dioptres or less, whereas two to four lenses were required to achieve reduction of more than four dioptres. Success, defined as the percentage of the target reduction agreed with patients that was actually achieved, was reported as better than 80 per cent for most practitioners. The time for trial lens wear was from 15 minutes to four hours and was 30 minutes in most cases. Suction holders were generally used for lens removal. Foggy vision was the most frequently reported adverse symptom and mild corneal staining the most frequent sign. Conclusions: It is clear that there is considerable variation in the practice of ortho-k in Hong Kong even among the relatively experienced practitioners interviewed here. The skills of contact lens practitioners in Hong Kong vary considerably because of the nature of the registration arrangements. We suggest that a statement of best clinical practice for ortho-k should be developed to assist practitioners to carry out this procedure effectively and safely.