Club class

Three international experts on rigid contact lens fitting came to the UK last month for the latest gathering of Ciba Vision's Specialist Club members. Alison Ewbank reports

What is a specialist contact lens fitter? A practitioner who fits the occasional gas-permeable lens, or one who regularly fits complex lens types to diseased or damaged eyes?

Ciba Vision's latest Specialist Club meeting, held near Oxford last month, catered for practitioners of all skills levels. More than 85 members heard three of the world's leading exponents of RGP lens fitting share their experiences. The combination of lectures and workshops proved a successful formula for the meeting which, like previous ones, was oversubscribed.

Opening the programme, US optometrist Ed Bennett said that the way that RGP lenses were presented by the practitioner had a profound effect on patient adaptation and acceptance of the modality.  His first advice was always to describe the lenses as 'gas-permeable' rather than 'rigid' or 'hard'. Using fear-arousing terms such as 'discomfort' resulted in more patients dropping out during the adaptation period than when neutral terms like 'lens awareness' were used.

A second ingredient in successful RGP practice, though controversial, was the use of topical anaesthetic during trial fitting. For Dr Bennett, the benefits were a better initial experience for the patient and reduced chair time. New RGP wearers given topical anaesthetic had a better perception of their adaptation, greater overall satisfaction and lower drop-out rate than patients given a placebo.

The third key factor was vision, where RGPs had a major advantage over other modalities, particularly if the initial trial lenses were close to the patient's prescription. 'If they have good vision from the first pair of lenses they wear they may also perceive the comfort as better,' he said.

Dr Bennett said that the lens parameter that most influenced comfort was diameter. Large diameters in excess of 10mm were perceived as significantly more comfortable over the first four hours of wear than other lens designs. Fitting characteristics that aided centration, such as lid attachment, lenticular and ultrathin designs, could also help improve comfort.

Young people from the age of eight years were prime candidates for RGP lenses, he said. In the most recent study of eight to 11-year-olds, nearly 80 per cent successfully adapted to RGP lenses. Those continuing to wear RGPs showed less myopia progression after three years than those switched to soft lenses but there was no difference in axial length between the two groups.

Dr Bennett's view of the current status of RGP lenses was optimistic. 'When we look at gas-permeable lenses today, we're looking at a modality with new and better materials. We're getting a good handle on the comfort issue in terms of the ingredients that manage comfort. And any problems that occur are well managed with different lens designs.'