Period Of Lens Wear Research Articles

The incidence of ophthalmic problems in the contact lens wearing population

In a prospective study all contact lens wearers presenting to the ophthalmic casualty department of the University Hospital Nottingham within a six month period were examined to determine the number and pattern of ophthalmic problems occurring in this group. This information was then compared with prescribing information from contact lens dispensers in the city. The incidence of problems associated with contact lens wear within the first six months of starting to use a new contact lens was found to be 0.9% for soft daily wear lenses and 0.8% for rigid lenses. Reservations about these figures are discussed. The similarity between the incidence for the two types of lenses appears to contradict previous suggestions that soft lens wearers are more at risk of developing complications. It may be that the early period of lens wear represents a favoured time with respect to soft lens induced disease while hard lens problems are more common at this time. Both giant papillary conjunctivitis and corneal ulceration were seen in significant numbers but neither were associated with one particular lens type.

EXTENDED CONTACT LENS WEAR IN THE DEVELOPING CYNOMOLGUS MONKEY EYE

Soft extended wear contact lenses were designed for and fitted to 12 eyes of 11 infant semiwild cynomolgus monkeys. The lenses were satisfactorily worn over observation periods of up to 465 days, the longest continuous period of lens wear being 69 days. However, some of the corneas were subject to a pattern of complications analogous to that in human contact lens wear. Nine eyes showed adverse responses, and of these, the ocular complications were severe enough in four cases to cause abandonment of lens wear. The most remarkable feature of the complications was the rapid recovery of severe reactions to near normality in less than 24 h, indicating an impressive ability of the cornea to tolerate and survive insult. Another feature was the recurrent nature of mild complications in certain monkeys despite apparent resolution from previous episodes. There appeared to be no correlation between duration of lens wear and appearance of the first or recurrent episodes of corneal infiltration and vascularization.