therapeutic topics

Mixing Anti-Depressants with Contact Lens Wear

therapeutic topics
Mixing Anti-Depressants with Contact Lens Wear

The list of the most widely prescribed medications in the United States reveals how many drugs physicians prescribe to combat the common problems of hypertension, depression, anxiety and similar categories of stress-related ailments. Because these categories of systemic medications are so common in our patient population, we should investigate their possible interactions with contact lens wear.

Dealing with Depression

Demographics of anti-depressant medication use show that in the last 15 years, the number of Americans under treatment for depression has increased from approximately 1.7 million people to more than eight million.

Historically, the first generation of therapeutic anti-depressants were monoamine oxidase inhibitors (MAOIs) that block the breakdown of norepinephrine in the synapse. Physicians have largely abandoned drugs in this classification because they can cause a large number of side effects and food and drug interactions. The second generation were tricyclic anti-depressants that stop the reuptake of norepinephrine.

New categories of anti-depressant agents act on different categories of neurotransmitters. They include selective serotonin reuptake inhibitors (SSRI) and serotonin and noradrenaline reuptake inhibitors (SNRI). The efficacy of these drugs seems generally comparable to the tricyclic anti-depressants with fewer systemic side effects. Tricyclic and SSRI anti-depressants currently account for 95 percent of prescribed anti-depressants.

Know the Side Effects

Although the use of SSRI anti-depressants is rising, many patients still take tricyclic anti- depressants. The tricyclic antidepressants are a particular concern for eyecare practitioners because they have anti-cholinergic side effects with obvious ocular implications. Common side effects noted with these medications are mydriasis, decreased accommodation and visual blur. Although these complaints aren't confined to contact lens wear, it's easy to see how you could mistake one of these side effects for a contact lens-related problem.

How They Affect Lens Wear

Mydriatic pupils in contact lens practice can be troublesome with any contact lens design that is pupil-size dependent. Visual blur may be the most common complaint as a result of the combined pupillary dilation and decreased accommodative function.

Contending with larger-than-normal pupils in GP lens patients often results in complaints of flare and glare because the optic zone may not be large enough to cover the entire pupil. Any intersection of the pupil with the edge of the optic zone will result in less-than-desirable visual performance.

Ironically, some soft and GP multifocal designs work better with a larger pupil size, so mydriatic pupils may result in varying levels of multifocal contact lens success.

The anti-cholinergic side effects of the tricyclic anti-depressants may result in a loss of accommodation that can easily cause pre-presbyopic patients to need plus power. You should address the near and intermediate visual complaints of these patients. Consider over correcting them for near and/or using other "presbyopic" contact lens solutions such as monovision and multifocal lenses.

It's All About Being Prepared

Understanding the visual side effects associated with tricyclic anti-depressant medications can help you anticipate and offer solutions for the contact lens problems they may cause.

Dr. Schornack is the assistant dean of Clinical Education and serves in the Cornea and Contact Lens Service at the Southern California College of Optometry.