prescribing for presbyopia
How Age-related Changes Affect Contact Lens Prescribing
BY TIMOTHY B. EDRINGTON, OD, MS & JULIE A. SCHORNACK, OD, MED
Aging causes subtle and dramatic changes to the body, particularly to the eyes. Presbyopia, increased dry eye symptoms and even decreased manual dexterity are some of the challenges we must keep in mind as our patients age. In this article, we discuss how you can help your patients manage these changes for optimal vision and comfort.
Ocular Effects of Aging
The aging eye undergoes numerous changes, both structural and functional, for example:
� Eyelids. As patients age, their eyelids gradually lose elasticity, resulting in reduced eyelid muscle tonus. On the plus side, patients may be less aware of the edge of a GP lens, which may lead to faster and more complete comfort adaptation. On the minus side, GP lens removal may become difficult. Generally, you can rectify this problem by modifying the patient�s lens removal technique or prescribing a removal device.
� Eyelashes. As people age, they may be more prone to ectropion, entropion or trichiasis. You may need to prescribe a soft contact lens as a bandage to protect the cornea from inturned lashes and to minimize discomfort. The use of lubricants during lens wear and ointments at night after lens removal also may increase comfort and wearing time for these patients.
� Corneal sensitivity. The corneal touch threshold increases with age, especially after age 40. Although this may result in faster adaptation to contact lenses, older patients may not become aware of contact lensrelated complications as quickly as younger patients do. Thus, lack of subjective complaints may seem out of sync with what you observe on slit lamp examination.
� Pupil changes. Pupil size decreases with age. Thus, patients who were successful wearing simultaneous (aspheric or annular) design multifocal lenses may find they need more add, or they may experience blurred distance or near vision.
� Cataract. Cataract formation may reduce the amount of light reaching the retina, resulting in decreased visual performance. Light reaching the retina of a 60-year-old may be only one-third the amount of light reaching the retina of a 20-year-old.1
� Other ocular diseases. Macular degeneration and other age-related ocular diseases and conditions also may lead to reduced vision.
Increased Dry Eye Prevalence
Eyecare practitioners know that many soft contact lens patients experience end-of-day dry eye symptoms. Aging exacerbates these symptoms. For example, tear flow may be reduced, or the integrity of the tear film may be compromised by the use of systemic medications. Patients with arthritis often present with dry eye symptoms as well.
To decrease or alleviate symptoms of dry eye, our prescribing options include rewetting drops and ointments, punctal occlusion, omega-3 fatty acids, eyelid scrubs and warm compresses. Changing contact lens materials and lens care solutions also may help. If these remedies do not improve wearing time and comfort, patients may need to reduce wearing time or wear their lenses on a part-time basis. Daily disposable lenses, which are available for monovision and multifocal correction, are a good option for these patients.
Some older contact lens patients may experience difficulty applying, removing and handling their lenses, particularly if the lenses have a very thin overall profile or a low material modulus. For patients new to contact lens wear, you may consider initially prescribing a thickerprofile lens, then switching to a thinner-profile lens after they become comfortable with handling the lenses.
Presbyopic patients, especially hyperopes, appreciate handling tints that help them locate the lens in the case or if it�s a wayward lens, on the countertop or the floor.
60 � It�s the new 40
Members of the baby boomer generation are projected to live longer and are likely to be more interested in maintaining appearances and enjoying active lifestyles than previous generations. Given advances in contact lens materials, designs and care systems, eyecare practitioners can successfully prescribe contact lenses to a more diverse age range of patients. This generation wants choices, and we have many presbyopic contact lens options to offer. Remember, we � and our patients � are becoming wiser with age.
1. Benjamin WJ, Borish IM. Presbyopia and the influence of aging on prescription contact lenses. In: Ruben M, Guillon M, eds. Contact Lens Practice. London: Chapman & Hall Medical, 1994:769.
Dr. Edrington is a professor at Southern California College of Optometry (SCCO). E-mail him at firstname.lastname@example.org. Dr. Schornack is associate dean of clinical education at SCCO and serves in the Cornea and Contact Lens Service at the Southern California College of Optometry.
prescribing for presbyopia