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CONTACT LENSES: New method for eye medicine delivery.

Contact Lenses are normally just another form of vision correction.  […]

By Published On: 21 December 20113.1 min read

Contact Lenses are normally just another form of vision correction.  You go to the optometrist with blurry vision and after glasses, contact lenses are the next most common form of vision correction that is chosen.

Contact lenses can have other functions, other than correcting vision blur.

They can change your eye colour from brown to blue.

They also can protect your eye after being scratched, similar to a bandage.  By placing the contact lens on top of the injured eye (and normally adding antibiotic eye drops to protect the eye from infection) it buffers the eyelid from blinking on the wound.  A scratched eye can be excruciating, so a bandage contact lens can be a godsend!

In a previous post we discussed how contact lenses are in the preliminary stages of adding electrical circuitry which can be used to measure the internal pressure of the eye 24 hours of the day.

Now it seems that accurate eye medicine delivery can be achieved using contact lenses.Does this mean that eye drops could be a thing of the past?  See the video below for an introduction to eye medicine delivery through a novel contact lens design.

The Byrne Lab in the USA has developed polymers that can be moulded into contact lenses.  These contact lenses can be impregnated with therapeutic medication, whether it be for bacterial infection, reducing eye pressure in glaucoma or to reduce inflammation.

Potentially this could be a tremendous step forward for eye disease management.

Eye drops have significant disadvantages:

  • The patient or their carer has to remember to put the eye drops in the eye/s. Compliance is a huge issue with up to 50% of patients not compliant with any form of disease treatment.  Eye treatment is no different.
  • In eye drop form, the drug needs to be in relatively high concentration as the contact time with the treated eye is short.  This is because most of the drop will quickly either spill out of the eye or will be drained away through the nose into the gut.
  • Most eye drops need to instilled multiple times per day, in fact in some severe bacterial infections eye drops are required every 15 minutes, around the clock.  Realistically this needs to be done in a hospital environment so is very expensive.

Delivering eye medication through contact lenses has a number of significant advantages:

  • Once the medicated contact lens is put in the eye by the treating optometrist or ophthalmologist, the patient does not have to do anything else, so compliance will be no longer an issue.
  • Treatment will be more effective, as a calculated dose will consistently be delivered for what ever time frame is required.

Possible pitfalls with this treatment will be:

  • Often treatment requires two or more eye drops.  Normally with eye drops, one medication is used followed by the second one 5 minutes later so that they will not dilute each other. Mixing two medications in the matrix of a contact lens will have all sorts of unexpected chemical reactions.
  • We suspect multiple medication contact lenses will take significantly longer to get to clinical trials if they make it at all.

Future eye medicine delivery techniques:

Even though eye drops are a reasonable way to treat most eye issues there certainly is a need for superior methods.  The contact lens delivery method is one such enhancement but this will have strong competition from Nanoparticle technology.  Nanoparticles are microscopic entities that have very specific chemical properties that allow the nanoparticle with the medicine piggybacked on it to more efficiently enter the eye.

Time will tell which technology takes over from the traditional eye drop approach.


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