Contact Lenses for Dry Eyes
Firstly let us consider the the tear film and it’s function.
Made up of several layers comprising of aqueous, protein and lipids. Produced by the lacrimal gland and complimented by the glands in the eye lids. The normal course of events is the tear film is replenished across the eye each time we blink. Ideally the tear film has enough integrity and stability until the next blink replenishes it once again. Many conditions, situations and environments can interfere with this. Introducing a contact lens in the eye is a mayor cause of disruption. The tear film needs to replenish the front surface of the contact as it would normally replenish the cornea.
The composition of the contact lens is a major factor in the success of this. Frequently the material the contact lens is made of does not attract and retain the tear film as the natural cornea does. As the lens ages even from morning to night it’s composition can change. Contact lens manufacturers frequently add a lubricant to their lenses that gets released as the day progresses for this reason.
Dry spots evident on staining
So which contact lenses are suitable for dry eye. There are many which I will document. In my clinic I generally try and prepare the eye for a contact lens, have the eye is hydrated to increase the capability to enjoy a comfortable stress free day. Lubricating the eye with a viscous oil lubricant at night is often a good plan. This oil layer of the lubricant will retain the natural tear film and hydrate the eye while you sleep also providing a barrier to dehydration eye during the working day.
More and more people are office based working on a VDU and in an air conditioned environment. A reduced blink rate when concentrating on a task is a come issue. Not easy to be aware of your blink rate when we generally blink on average 15 times each minute. Missing a few hundred blinks a day can be hard to notice.
Contact lenses for dry eye have a few advantages over the cheaper contact lenses, namely they have greater oxygen transmissibility and thus cause less stress to the cornea. If the eye perceives an irritant in the eye it will trigger the lacrimal gland to produce tears to flush out the irritant. People are incredulous to believe their streaming eyes can be triggered by dry eye as the opposite appears to be the case.
Contact lens manufactures go to great lengths to mimic the composition of the cornea to match as closely as possible the structure they want to cover and interact with the tear film in as natural an environment as possible.
High oxygen transmission, incorporating a lubricant and having the outter coat of the contact as friendly to the tear film, are some of the methods to achieve this integration.
Which lens should you choose Ciba Vision have an Aqua comfort plus and now they have released a new Dailies Total 1 which has an 80% water content, the highest on the market currently.