Contact lenses are no longer a medical marvel to most patients. While patients who need contacts for medical conditions can experience life changing improvement, clear vision with these small devices is pretty much taken for granted by the rest of the population.
I was first fit in soft contact lenses at the age of 11. I wore lenses to correct my astigmatism (yes, they made toric lenses for astigmatism even then), and continued to wear them for 18 years. I then opted to correct my vision with LASIK and was extremely happy with that choice until my reading vision began to weaken 12 years later. Because I had had such good success with contacts in my younger years, I tried wearing several different types of contacts to correct my vision at near. I found that because I was now in my forties, nothing was as comfortable, because the tear film that should float the contact above the cornea was thinning with age. We dry out as we get older. Many patients don’t realize the importance of the relationship between the contact lens and their tear film.
The tear film is secreted by glands known as lacrimal glands. As these glands age, they simply don’t produce the volume of tears that they did when we were younger. The tear film is composed of three separate layers: a mucous layer that lies against the surface of the eye, an aqueous, or water layer above that, and an oily layer on the surface. If a patient is lacking in one or all these layers, they will struggle with contact lens wear due to poor comfort, vision, or both. Common complaints may include dryness, redness, or irritation.
Contact lens patients who complain of fluctuating vision, especially when they blink, is usually the result of instability of the outer oily layer of the tears. Without this layer, the underlying water, or aquaeous layer begins to evaporate much faster than normal. Causes of this lack of oil production in the tears include dysfunction of the oil glands in the eyelids (known as meibomian glands) or a lid condition known as blepharitis. Both conditions can be improved with attention to lid hygiene; I recommend using medicated lid scrubs twice a day to keep the oil glands open and free of debris and dead skin cells. Also, ten minutes of dry heat applied twice a day can go a long way towards keeping the oil glands flowing properly. Artificial tears that have more of an oily component are also beneficial.
Sometimes, the discomfort and blurring of vision is due to poor wettability of the lens itself. This is often the case in patients who develop deposits quickly on their lenses. These deposits are usually made up of proteins and fats found in the tear film. Other deposits can be from outside sources, such as soaps, hairspray, and lotions. This is one of the reasons the use of daily disposable lenses has skyrocketed. Surface deposits are extremely rare to see if the patient is putting in a fresh clean contact lens every day.
Scleral lenses, as well as rigid gas permeable lenses have a harder time maintaining wettability. The materials used in the manufacture of these lenses typically don’t attract water. Cosmetic products are more prone to contaminate these lenses, further reducing lens wettability. The cleaning regimen of these types of contact lenses include the use of a strong laboratory style cleaner and conditioner to enhance comfort and vision.
Another issue with patients who demonstrate less than adequate lubrication of the ocular surface is mechanical irritation between the contact lens and the tissue inside the eyelids known as the palpebral conjunctiva. This tissue is supposed to glide smoothly across the surface of the contact lens with every blink. In drier eyes, the conjunctiva rubs across the lens, leading to the development of large bumps inside the lid which make wearing the contacts even more uncomfortable. This is known as giant papillary conjunctivitis.
I recommend that contact lens patients complaining of comfort or fluctuating vision use a good rewetting drop at least four times a day. Adding a recommended ointment at night is also beneficial if drops alone are not adequate. Restasis, Xiidra, and Cequa are topical medications that can be used to help decrease inflammation in dry eye cases that are not responding as well with lubrication alone. Various oral supplements have also proven to be helpful at increasing tear production.
For patients who are having difficulty wearing their contacts comfortably, it is important to discuss this with their eye doctor. Identifying and treating any underlying conditions such as inadequate tear film can greatly improve the patient's ability to continue wearing contact lenses for years to come.