Introduction The term ‘extended wear’ (EW) has generally been applied to describe the wear of contact lenses for periods in excess of 24 hours between removal, including sleep with the lenses on the eye and regular, planned removal of the…
Introduction One of the more perceived challenging areas within contact lens practice is fitting presbyopic patients with contact lenses to allow the majority of their visual requirements to be met through the development of their presbyopia. However, the availability of…
Introduction Eye colour is universally recognized as an important and defining natural physical characteristic of the body human, and a contact lens is an effective vehicle for modifying or enhancing this appearance for those who wish to do so. More…
Introduction Contact lenses can be broadly categorised according to their frequency of use and frequency of replacement. Daily disposable lenses, which are worn during the day and discarded at the end of the day, are single-use, daily replacement lenses; this…
Introduction Daily disposable lenses are one of the two versions of true, single-use-only, contact lenses – the other being extended-wear lenses. Daily disposable lenses first became available in 1994. The premier daily disposable lens was launched in the United Kingdom…
Introduction This chapter reviews the care systems used with rigid contact lenses. Of course, many of the general principles of contact lens care, such as the rationale for lens cleaning and disinfection, regulatory control of the contact lens care industry…
Introduction and Historical Overview Scleral lenses were the first contact lenses used to protect the ocular surface, restore vision in keratoconus and correct simple ametropia ( ). Initially manufactured in glass and later polymethylmethacrylate, Sattler’s veil (corneal oedema) was common…
Introduction The use of rigid toric corneal lenses (in preference to rigid spherical corneal lenses) is indicated under the following circumstances: 1. To improve the vision in cases where a lens employing spherical front and back optic zone radii is…
Introduction Fitting rigid corneal lenses is an improbable achievement. Essentially, it involves constructing a complex three-dimensional structure to sit, without the aid of any supplementary adhesive, on a vertically inclined surface while being repeatedly dislodged by a covering structure. Fortunately,…
Introduction In contrast to soft lenses (see Chapter 7), rigid contact lenses are individually fitted and then lathe cut to meet particular optical, geometrical and material specifications. Although the manufacturing precision has improved significantly over the years, in particular with…