Commonly Prescribed Soft Contact Lenses and Pearls for Their Use

The contact lens market in 11 reported countries across Europe was valued at more than €1 billion in 2012, with an estimated 3.4% to 13.3% of the population 15 to 64 years old wearing contact lenses.¹

In addition to being a cosmetically pleasing option for many patients, contact lenses have several advantages over spectacles for refractive correction: They provide the ability to easily alter the lens power with changes in refractive error; they do not irritate the face or have the potential to fall off, especially when playing sports; they do not steam up or need wiping; they cause minimal magnification effects both for observers and for the wearers seeing through them; and they even offer patients the ability to change their iris color or to add definition to the limbus and pupil margins.

Acknowledging the barriers

Despite their advantages and benefits, there are some barriers to more widespread contact lens use.

Myopia control. Recent studies of multifocal contact lenses and orthokeratology—a program of overnight rigid lens wear to redistribute the epithelium and correct refractive error—have demonstrated the ability of these modalities to slow myopia progression by up to 50%.^2,3 Interest is growing in myopia control across the globe, yet it is making little difference on contact lens (or other eye care) practice.³ The peak ages of contact lens wear are still in the late teens to early 30s, after which there is a drop-off in wearers even before presbyopia sets in.⁴

Fighting the dropout effect. Many studies have shown a dropout effect, with one-third to one-half of patients discontinuing contact lens wear during the first 6 months of use; this has largely been attributed to discomfort, particularly late in the day.^5,6 Therefore, a large focus in current prescribing is on providing better care after fitting.

Another area of focus is on fitting the most comfortable contact lenses, often daily disposables, to avoid compliance issues with solutions and lens cases.⁷ Many of these lenses now offer high levels of comfort even after 16 hours of wear.^8-10

Care solutions. Certain contact lens solution disinfectants and preservatives interact with specific contact lens materials—particularly silicone hydrogel—to cause marked corneal staining around 2 hours after lens insertion, but this effect disappears during the day.¹¹ This has challenged clinicians’ thinking on whether fluorescein staining represents damage of the ocular surface or not, with studies reporting inconsistent results on whether the staining has any association with contact lens discomfort or complications.^12,13

Lens fitting. Soft contact lens fit on the ocular surface is not well predicted by keratometry and video topographic assessment,¹⁴ and, therefore, fit must be assessed on a patient-by-patient basis. This makes substitution of lenses through Internet purchase potentially unsafe.¹⁵

Contact lens OPTIONS

Toric lenses. Toric contact lenses have become more stable and easier to fit over the years, and toric options are available in all modalities of wear and in combination with presbyopic optics. These lenses are now being prescribed for the approximately one-third of contact lens–wearing patients who are likely to have significant amounts of astigmatism.¹⁶ It is always good practice to allow patients to compare a spherical equivalent power with a toric contact lens—for instance, by placing one type of lens in each eye—so that they can assess the difference. There is a price differential, and this experiment can inform their choice. However, clinicians should remember that uncorrected toric prescriptions have been identified as a reason for contact lens discontinuation.¹²

Multifocal lenses. Correction of presbyopia with contact lenses is largely achieved with models that produce simultaneous multifocal images, rather than with monovision.⁴ Unlike IOLs, all commercially available multifocal soft contact lenses are concentric refractive designs, despite early research on diffractive optics. Our recent research suggests that alternating designs between eyes (center distance in one eye and center near in the other) is preferred by patients, but this approach has not been widely adopted to date.¹⁷

LENS MATERIAL

Although the use of silicone-hydrogel contact lenses continues to increase at the expense of traditional hydrogel material contact lenses due to their clear advantage in oxygen permeability, there is still debate about whether they are the best option for all patients. It is generally agreed, however, that extended wear schedules (ie, sleeping in lenses) carries an unacceptable level of risk for most patients, even with the latest material innovations.¹⁸