What are INTACS?
INTACS are a specific type of intrastromal corneal ring segment (ICRS) used to change the shape and curvature of the cornea to improve vision and/or lessen astigmatism. There are several different types of ICRS available for placement within the cornea, but INTACS are the most widely used and studied.
How do INTACS work?
INTACS are placed within the central stromal layer of the cornea and oriented in such a way to support and reshape the cornea to improve vision. When placed, the INTACS segments are fully within the cornea and not exposed to the outside world or the inside of the eye. The ring segments are placed outside of the central cornea, reshaping it in order to improve vision.
What types of corneal issues are appropriate for INTACS?
Although originally used to improve near-sightedness, INTACS (not sure need to mention ICRS after first section) are now used for corneas that have an irregular shape and astigmatism. An irregularly shaped cornea is said to have an ectasia, or to be ectatic. Examples of corneal ectasias are keratoconus, pellucid marginal degeneration and post-LASIK ectasia. Often an ectatic cornea has thinning in a certain area that leads to irregular astigmatism or a protrusion of the cornea. INTACS placement can reduce the irregularity or astigmatism of the cornea, leading to improved vision.
Who are appropriate candidates for INTACS?
Appropriate candidates for INTACS are patients who have corneal thinning but are not too thin to accommodate the ring segment within the cornea and who are no longer able to tolerate rigid gas permeable contact lenses. Often, the placement of INTACS will reduce the level of irregularity or astigmatism, but glasses, contact lenses or rigid gas permeable contact lenses are often still needed to achieve a patient’s best vision.
How are INTACS placed?
The eye is anesthetized using topical drops to prevent discomfort during the procedure. One or two small, partial-thickness incisions are placed in the cornea and a pocket is made in the cornea. The eye is then pressurized and blunt precise semi-circular dissectors are used through the pockets to make a partial thickness channel within the stroma of the cornea. The INTACS are then placed in the channels, and the incisions are closed. Topical antibiotic drops and anti-inflammatory drops are used after surgery. Recovery takes several weeks, with vision improving over this time. Eventually, glasses, contact lenses or rigid gas-permeable are used to achieve full visual potential.