Background

Newer contact lens materials, both rigid and soft, allow the passage of oxygen through lens to the cornea and enable extended wear of the lenses. Extended wear (EW) lenses have proven popular because of their convenience. However, concerns regarding the relative safety of these lenses prompted several studies to examine the rate of adverse reactions among contact lens users.

In a series of studies 1-5, the risk of developing ulcerative keratitis (corneal infection) was:

Four to 10 times greater in EW versus daily wear (DW) lens users;
Nine times greater in elderly patients using EW lenses for correction of aphakia;
Nine times greater in individuals misusing DW lenses for overnight wear;
Proportionally greater with increased consecutive days of EW lens wear before removal;
Less with more frequent lens removal, lens care and especially with frequent contact lens case cleaning.

Recommendations

In May 1990, the Food and Drug Administration (FDA) issued recommendations that EW contact lenses be worn no more than seven consecutive days.

Disposable (or programmed replacement) contact lenses do not reduce the risk of corneal infection. Overnight wear of contact lenses is an added risk factor for infection, whether or not the lenses are disposable.3-5 The need for user compliance with scheduled lens replacement and follow-up must be emphasized.

Acanthamoeba keratitis is an infrequent but serious infection among contact lens wearers. Because of the increased risk of Acanthamoeba keratitis among individuals using homemade saline solutions for lens care, the FDA has banned the sale of salt tablets for such solutions. Red eye and discomfort may signal early infection with Acanthamoeba keratitis or another micro-organism. Any individual using EW contact lenses who develops symptoms should remove the lens and see an ophthalmologist promptly.

Deposits which form on soft contact lenses may be lessened by careful lens hygiene. Lens intolerance associated with these deposits, including giant papillary conjunctivitis, is higher in soft EW lens wearers. These conditions may necessitate changing the lens or discontinuing the use of soft contact lenses.

Smoking may increase the risks of corneal infection and is a contraindication to the use of EW contact lenses.

Conclusion

Eye Care Professionals recognize that the overnight (extended) wear of contact lenses can be a useful and safe method of correcting refractive errors in properly selected and carefully monitored users. However, the extended wear of contact lenses has the potential for causing severe ocular damage when there is inadequate instruction, lack of user compliance and insufficient professional supervision. The incidence of complications, particularly infectious keratitis, is higher with EW soft lenses. Studies confirm the importance of good education, hygiene, and compliance for safe and successful EW lens wear. The fitting of EW lenses and monitoring of the user should be performed by practitioners such as ophthalmologists who have the professional training and experience to recognize and treat the potential complications.

References:

MacRae S, Herman C, Stulting RD, Lippman R, Whipple D, Cohen E, Wilkinson CP, Scott C, Smith R, et al: Corneal ulcer and adverse reaction rates in premarket contact lens studies. Am J Ophthalmol 1991; 111:457-465.

Schein OD, Glynn RJ, Poggio EC, Seddon JM, Kenyon KR: The relative risk of ulcerative keratitis between extended- and daily-wear soft contact lens wearers: A case-control study. N Engl J Med 1989, 321:773-778.

Poggio EC, Glynn RJ, Schein OD, Seddon JM, Kenyon KR: The incidence of ulcerative keratitis among daily and extended-wear soft contact lens wearers. N Engl J Med 1989;321:779-783.

Matthews TD, Frazer, DG, Minassian DC, Radford CF, Dart JKG: Risks of keratitis and patterns of use with disposable contact lenses. Arch Ophthalmol 1992; 110:1559-1562.

Schein OD, Buehler PO, Stamler JF, Verdier DD, Katz J: The impact of overnight wear on the risk of contact lens-associated ulcerative keratitis. Arch Ophthalmol 1994; 112:186-190.
Approved by:

Board of Directors
June, 1985
Revised and Approved by:

Board of Directors
June, 1992
Revised and Approved by:

Board of Directors
September, 1997