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Children and lenses
Dr Jeffrey Walline is probably best known to readers for his papers on fitting children with contact lenses and his demonstration that this bore little impact upon chair time. The average age of first time fits in the UK is 14-15 years of age and in Asia 17-18. The US tends to fit first time at a younger age, between 12 and 13 years. Dr Walline's first point was that younger patients may benefit from lenses and that the numbers of young patients fitted might be considerably increased if it was made known that children could be fitted with contact lenses. 'Put up signs in the waiting room,' he pleaded, 'and make sure that all practice staff are on message.' In the speaker's experience, it only needs one misinformed staff member to deter whole swathes of patients. Longer term, if one child is successfully fitted with lenses, the knock-on effect to family, friends and schoolmates is a useful practice builder.
Dr Walline's second pearl of wisdom was to remove the parents from the room, particularly if they are in disagreement. He has a useful trick of providing wi-fi access in his waiting room and as soon as he feels a parent is a distraction or source of contention, he will offer them free internet access. They rarely ever refuse! The main priority from the initial discussion was to ensure the child maintains enthusiasm for lenses. 'Like dogs, children can sense when you are uneasy.' During one of the lively video link question sessions, a Bristol-based delegate asked whether parents might resent yet another future drain on their resources. Dr Walline reminded everyone of the known benefits of contact lenses for children and that at some stage a balance should be struck between cost and benefit.
Oxygen flux
After showing how he was able to control the lecture from his iPhone while wandering throughout the auditorium, the ever entertaining and lucid Professor Noel Brennan offered a useful reminder of how corneal oxygenation is influenced by contact lens material. The move to silicone hydrogel material has allowed oxygen permeation of the lens material way beyond what was possible with conventional hydrogels and over and above that which previous research has specified is required to maintain healthy and non-oedematous corneas. The industry norm of stating transmissibility for any given lens material as an indication of the amount available to the cornea had been branded a 'disappointment' as long ago as 1996 by as significant a figure as Irving Fatt himself. Dk/t makes it difficult to allow accurate lens comparisons and also is a lab based measurement rather than in vivo. 'It is important to know how much oxygen is needed,' argued Brennan. 'The amount of oxygen that moves across the front corneal barrier, the flux, is important, but you also need to know the flux at the back of the cornea too. This net flux is an indication of the oxygen consumption by the cornea.'
It is now well known that the anterior oxygen flux increases along with Dk/t but eventually plateaus such that higher Dk/t values have decreasing impact on the available oxygen to the cornea. Thus the drive to ever higher Dk/t values is misplaced. Brennan also noted how there are similar rates of microbial keratitis (MK) in silicone hydrogel wearers (albeit of lower severity) and conventional hydrogel wearers. Recent lists of risk factors for MK include overwear, reduced hygiene, male gender, socioeconomic factors, youth, and so on, but not oxygen. The main benefit to wearers of increasing oxygen provision has been to reduce redness at the limbus.
Mixing the innovative with the informative, and a healthy dose of controversy, is a good way to organise a CET event. ?