A study of the suitability of disposable coloured contact lenses for a South African clinic based population

Abstract

Optomet

rists have always considered the fitting of all types of contact lenses to be an integral part of the scope of practice of their profession.  However, since the introduction of disposable cosmetic coloured contact lenses into the market, the frequency of over the counter sales of contact lenses has significantly increased.  Patients often present with contact lens complications at the University of Kwa-Zulu Natal clinic and local practices.  It is sometimes reported that the lenses were purchased over the counter, from an optometry practice or another non-registered vendor.  A common observation in these instances has been that the lenses do not fit optimally and that the incidence of complications associated with tight fitting lenses was much higher amongst the African patients as opposed to those of other race groups.  A clinical observational study utilizing convenience sampling of 240 subjects was undertaken to evaluate the fitting criteria of disposable cosmetic coloured contact lenses on a South African clinic based population.  All patients requesting the lenses chose their preferred colour and were fitted with Freshlook ColorBlends, Images or Expressions Colors lenses.  Lenses were evaluated after 20-25 minutes and then classified into tight, ideal or loose fits according to the lower lid push-up test, lenscentration, post blink movement and version lag and upgaze lens movements.  The ages of the subjects ranged from 16 to 45
years with a mean of 24.13 ± 5.66 years.  Seventy (29.2%) were males and 170 (70.8%) were females. The majority (62.9%) of the lenses fitted on the subjects were rejected according to the fit criteria. The African subjects had the highest percentage of rejected fits (82.8%) whilst 75% of the White subjects had acceptable fits.  The main reason for lens fits being rejected was that they displayed charac teristics of a tight fit (96%) with only 4% of the fits being rejected due to being too loose. These results
highlight the need for contact lens manufacturing companies to realize that those lenses that they design and which undergo clinical trials on Caucasian eyes do not necessarily fit well on the majority of patients in this part of the world.  The reasons for
this may be related to differences in corneal profiles of the different population groups with some being more suitable to particular lens designs than others. It is recommended that the public and practitioners be educated about the potential dangers of over the counter sales of contact lenses and that pre-fitting
evaluations consultations of all contact lenses are an essential part of contact lens care.