What Are Therapeutic (Bandage) Contact Lenses?
Also known as “Bandage Contact Lenses”, therapeutic contact lenses protect and aid in restoring ocular tissues in several eye disorders. A therapeutic contact lens in combination with precise medication provides an effective and often pain-relieving cover for the eye.
The word “therapeutic” is derived from the Greek word “therapeuein”, which means to take care of or to heal. It is not a separate category of contact lens because almost all lenses can be used for therapeutic purposes.
Ideal Therapeutic Contact lenses
The aims of therapeutic bandage contact lens wear
The major goal of bandage contact lens wear is to accelerate wound healing purposes. Although there is vision improvement with the integrity of the ocular surface, it is the secondary aim of the therapeutic contact lens.
The main aims of therapeutic contact lenses are given below:
- Mechanical protection and support
- Relief of ocular pain
- Drug delivery
- Maintenance of corneal epithelial hydration
- Promotion of corneal healing
Types of therapeutic bandage contact lenses
Almost every type of contact lenses presently available can be used for therapeutic purposes. Based on the material used to manufacture the lens, the following types of bandage contact lenses are in use:
- Hydrogel Soft Contact Lenses
- Low water content hydrogel soft lens (water content 38%-45%)
- Mid-water content hydrogel soft lens (WC 45%-55%)
- High water content hydrogel soft lens (WC 67%-80%)
- Silicone hydrogel Lenses (WC 38%)
- Hard (PMMA) and gas permeable scleral lenses
- Hard scleral rings
- Collagen shield with WC 63%)
Hydrogel soft therapeutic contact lenses
Bandage soft contact lenses are available in low to high water content.
High water content hydrogel soft bandage lenses
67-80 % water content lenses with plano power are available as bandage contact lenses. These therapeutic lenses are suitable for corneal epithelial defects as they act as support or bandage to the wounded cornea, thus minimizing the epithelial disturbances and aiding in pain relief.
Mid water content bandage soft contact lenses
Therapeutic contact lenses with 45 to 60% of water content are the best choices for small corneal perforations or leaking wounds because they act as a splint.
Low water content bandage soft contact lenses
Bandage contact lenses with 38 to 45% of water content are mainly used in eyelid disorders such as trichiasis. These therapeutic lenses act as a barrier between eyelashes and cornea, thus minimizing trauma to the cornea.
Silicon hydrogel bandage contact lenses
These are the high oxygen permeable lenses with 38% water content. There is a significantly lower level of hypoxia compared to other lenses, so useful for overnight or extended wear.
Silicone lenses are the lenses of choice in chronic and severe dry eye. These lenses are also used for wound healing in persistent epithelial defects and corneal ulceration.
Similarly, they are used in trichiasis, keratinized mucous membrane, and incomplete lid closure. Due to less flexibility, there is also a slight improvement in visual acuity.
Collagen shield is manufactured from porcine and bovine tissue. It is necessary to hydrate the cornea before inserting a collagen shield in the eye.
The shields soak in the drugs. Therefore, these lenses are mainly used for persistent and effective drug delivery to the eye. They are useful for antibiotics delivery in the cases of bacterial ulcers and post penetrating keratoplasty (PK).
But it is not appropriate for long term therapy. The patient feels greater discomfort and reduced vision compared to other lenses.
Rigid Gas permeable Therapeutic Contact lenses
Rigid lenses are frequently used for combined action of refractive correction and therapeutic purpose. All types of corneal abnormalities leading to irregular or high astigmatism are benefited visually with rigid contact lenses.
In eyes with conditions such as post keratitis, post-PK, traumatic cornea, keratoconus, the cornea is already compromised. So, lenses with high oxygen transmissibility should be fitted to prevent further damage to the cornea.
Limbal diameter rigid lenses cover the cornea and has many advantages over short diameter hard lenses. It offers complete corneal protection.
Likewise, it helps to maintain a corneal tear reservoir and can be used with topical medication.
Therapeutic uses of Scleral contact lenses
Scleral lenses of diameter 23 mm offer protection of both the cornea and the bulbar conjunctiva. Mini-scleral lenses with small diameters are also used for therapeutic purposes.
Large-diameter scleral lenses maintain a tear reservoir and protect the cornea from the shearing forces of the eyelids.
Scleral therapeutic lenses are used in severe dry eye, Sjogren’s syndrome, Stephen Johnson Syndrome, cicatrizing conjunctivitis, and corneal exposure.
Indications of scleral lenses are:
- irregular or abnormal corneal topography
- high astigmatism
- keratoconus or other primary corneal ectasias
- corneal transplant
- Traumatized eye
- Post-refractive surgery
- high refractive errors
- centration difficulties with high-power corneal lenses
- intolerance to corneal lenses
- iris encapsulation
- unsightly blind eyes
- intractable diplopia
- cosmetic shells
Other uses of scleral lenses
- scleral lenses are used for maintenance of fornices
- these are also used as ptosis prop
- also used for promotion of epithelial healing in the presence of a severe dry eye
- they are rarely indicated for pain relief in neurotrophic keratitis and persistent epithelial defects.
Therapeutic Bandage contact lens complications
In some instances, therapeutic contact lenses can lead to complications such as infectious keratitis, dry eye, corneal hypoxia, and corneal edema. The patient should maintain proper contact lens hygiene and contact eye care practitioner if the bandage contact lens falls out. Patients should never try to replace the therapeutic lenses themselves.
Advice to the patient who is using bandage contact lenses
You should avoid removing the lenses at home especially if you have no experience with contact lenses. The lens should be removed by the expert, once the epithelium is intact. Manipulation of the contacts by the patient can increase the risk of infection.
Similarly, you should avoid environmental pollutants and activities that significantly reduce the blink rate, which may cause dehydration of the contact lenses. Dryness of eyes causes discomfort, facilitates deposit formation, diminishes oxygenation of the cornea, and increases the risk of infection.
You should not use cosmetics around the eyes until the contact lens is removed. Likewise, use lubricating eye drops and other prescribed eye drops in order to lubricate and clean the lens. Discard the contact lens if it comes out of the eye.
Bandage Contact Lens Removal
Contact lens experts remove the bandage contact lenses. As the contact lens is firmly attached to the cornea always wet the lens with lubricating eye drops and wait 2-5 minutes before removing it.
Anesthetic eye drops can be used if necessary, to reduce the pain. Then, ask the patient to look up, pull the contact lens inferiorly and remove it with fingers or with a fine, non-toothed forceps using the slit lamp.
HealthKura does not provide medical advice of any kind. If you have any questions related to this, you can contact related health care professionals for more information.