Dear Dr. David,
I’ve tried contact lenses several times. I always develop an allergy to them. Are there any contact lenses which do not cause allergies?
All contact lenses are hypoallergenic*, because all contact lens materials are inert and immunologically neutral. So, in short, contact lenses materials do not cause allergic reactions. Their very nature is hypoallergenic.
But! I’m not saying, “Contact lenses do not cause allergies.” Contact lenses can be the very objective of eye allergies, but it is not because of the lens materials.
Contact lens allergies are because of: (a) your own protein that collects on the contact lenses, or (b) contact lens solutions. Contact lens solutions are less often an allergen* than proteins from your own eye, so I’ll address contact lens solutions in another blog.
The slick stuff you’ve noticed on your contact lenses after removal is protein. As your contact lenses sit in their case the slick stuff, i.e. the protein, denatures*.
The body is particularly adverse to its own denatured protein. In fact if it is injected directly in to the blood stream it causes serious consequences – even death.
Of course the antibodies* that develop in the blood stream because of contact lenses get there only by protein contacting the capillaries of the conjunctiva* of the eyelids and front of the eye. This is minimal contact at worst, so it takes time for the antibodies to develop.
How long? Week, months, years, maybe ten or fifteen years, but one thing is for sure. Once antibodies develop, they are like malaria – you have them for life, and contact lenses stop being convenient visual devices and become a tedious endeavor.
So follow your doctor’s advice concerning wearing schedules and care, and if at all practical use one day disposable lenses. Changing to daily disposable contact lenses virtually eliminates any issue of developing contact lens induced allergies!
*Hypoallergenic – relatively unlikely to cause an allergic reaction.
*Denature – a change in the molecular character of a protein by heat or chemicals. (A common example is a boiled egg.)
*Allergen – a substance that causes an allergic reaction.
*Conjunctiva – mucous membrane covering the front of the eye and lining the inside of the eyelids.
*Antibodies – a blood protein produced in response to and counteracting a specific allergen (antigen).
Photo credit: By BruceBlaus; Blausen.com staff (2014). “Medical gallery of Blausen Medical 2014”. WikiJournal of Medicine 1 (2). DOI:10.15347/wjm/2014.010. ISSN 2002-4436. (Own work) [CC BY 3.0 (http://creativecommons.org/licenses/by/3.0)], via Wikimedia Commons