Every experienced GP lens fitter can think of at least one patient who has worn the same pair of GP lenses for too long. This patient is often proud of the lenses’ advanced age, whether because of the money “saved” by not purchasing new lenses or due to a feeling of accomplishment from a self-proclaimed excellent lens care regimen.

Inevitably, these patients will either break or lose a lens and will need a replacement, assuming that they do not have three to four other old lenses from mismatched orders in a drawer that they can tolerate. Then, despite their inexplicable ability to wear old, deposited, warped lenses for months on end, refitting these patients into new GP lenses (even with identical, matched previously ordered parameters) often results in dissatisfaction and great difficulty in returning them to their previous level of lens tolerance.

How Did We Get Here?

Perhaps these patients’ eyecare practitioners have inadvertently encouraged this behavior by not recommending lens replacement prior to issues arising. In fact, many experienced GP lens fitters take great pride in being able to offer annual lens cleaning and polishing services to further extend the life of their patients’ GP lenses. This may be good customer service in the short-term. But, over many years, it encourages the eventually detrimental practice of wearing GP lenses for as long as possible, regardless of the complications that may arise from this habit.

When discussing soft contact lenses, the accepted norm is frequent replacement of lenses on a regular basis to avoid problems. GP lenses, however, seem to get the opposite recommendation, with practitioners advising patients to replace their lenses only if problems are reported or found on examination.

Most published research regarding recommended GP lens replacement is more than 20 years old, despite a resurgence of interest in GP materials for orthokeratology/myopia control and scleral lens designs (Jones et al, 1996). An online search of consumer-based websites on GP lens care reveals recommended replacement schedules of two years or longer, leaving patients with a rather vague replacement recommendation (Heiting, 2016; Contact Lens Manufacturers Association, 2015).

Recommendations

There are many reasons why GP lenses should be replaced more frequently. Lens warpage and corneal molding are significant concerns; these are not only problems when trying to refit patients into a newer lens (or when simply replacing an older lens), but also when patients are considering refractive surgery or when the corneal shape is critical to design performance (as in orthokeratology).

It is not uncommon for old GP lenses to be stored in even older cases, which can harbor bacterial biofilm and other contaminants. Additionally, deposited lenses reduce potential visual acuity and lens performance, and cracked, chipped, scratched, or damaged lenses can threaten corneal insult and abrasion. Newer GP lens surface treatments and coatings such as plasma or a polyethylene glycol-based polymer are not guaranteed effective beyond the first year of wear, even when compatible lens care systems are used. Finally, vague replacement recommendations lead to patient confusion and often unintentional noncompliance with the recommended frequency of eye examinations.

Given these reasons, annual replacement of GP lenses—regardless of lens condition—is a reasonable recommendation for practitioners to make. Along with more frequent replacement, both new and experienced GP lens wearers must be regularly educated on the importance of case cleaning and care, proper solution use, risks involved in wearing old lenses or lenses that are swapped, and proper storage (and replacement) of backup lenses.

Regardless of whether practitioners are trying to change the old practices of experienced GP lens wearers or to establish new wearers with a more proactive replacement schedule, it is time to challenge the previously held beliefs that GP lenses should last for an indeterminate number of years. CLS

For references, please visit www.clspectrum.com/references and click on document #271.