Laser-Assisted In Situ Keratomileusis (LASIK) is a refractive surgery designed to correct vision problems like nearsightedness, farsightedness, and astigmatism by reshaping the cornea. Chronic Dry Eye Syndrome (DED) occurs when the eyes do not produce enough quality tears or the tears evaporate too quickly, leading to irritation and discomfort. While LASIK is highly effective for vision correction, it does not treat pre-existing dry eye and is a common cause of temporary dryness in the post-operative period.
Why LASIK Can Cause Temporary Dryness
The mechanism behind post-LASIK dryness is primarily neurogenic, relating to the creation of the corneal flap. To perform the surgery, a hinged flap is made in the outer layer of the cornea, severing the sensory nerve endings in that area. These nerves, branches of the trigeminal nerve, are responsible for detecting dryness on the ocular surface.
When these nerves are temporarily damaged, the signal pathway to the lacrimal gland, which produces tears, is interrupted. This reduced nerve signal results in a decreased rate of tear production (neurotrophic epitheliopathy). The lowered corneal sensitivity also reduces the natural blink reflex, which is essential for spreading the tear film evenly across the eye.
This disruption impacts the tear film’s stability and increases the rate of tear evaporation, leading to the symptoms of dryness. Nearly all patients experience some degree of temporary dryness immediately following the procedure. For most individuals, these symptoms are transient, improving within a few weeks to six months as the corneal nerves begin to regenerate.
A small percentage of patients may experience symptoms for six months or longer; certain factors like pre-existing dry eye or a higher degree of vision correction can increase this risk. This temporary dryness is considered a normal, expected part of the eye’s healing process after corneal surgery.
Managing Dry Eye After the Procedure
Patients experiencing post-operative dryness are advised to follow a regimen to manage their comfort and support healing. The first-line treatment involves the frequent use of preservative-free artificial tears, which supplement the eye’s natural moisture without introducing irritating chemicals. These drops can be used as often as every hour in the initial recovery period to maintain surface hydration.
For more persistent symptoms, specialized prescription eye drops, such as cyclosporine or lifitegrast, may be used to help reduce inflammation on the ocular surface. This reduction in inflammation can then promote the eye’s natural ability to produce tears. Punctal plugs are tiny devices placed in the tear drainage ducts to slow down tear loss and keep moisture on the eye for longer periods.
Environmental adjustments also play a significant role in managing dryness after LASIK. Using a humidifier in dry indoor environments and avoiding direct airflow, such as from air conditioners or fans, helps minimize tear evaporation. Regular breaks from screen time and conscious blinking exercises are also recommended, as focused tasks often lead to a reduced blink rate.
Screening for Pre-Existing Dry Eye
Before considering LASIK, pre-operative screening for Chronic Dry Eye Syndrome is performed to determine a patient’s suitability. This evaluation is necessary because a pre-existing condition significantly increases the risk of severe, long-term dryness after surgery. Precise measurements of the eye are also affected by an unstable tear film, which can compromise the accuracy of the laser treatment plan.
Common tests used include the Schirmer’s test, which measures tear production volume using a small strip of paper placed under the lower eyelid. The tear break-up time (TBUT) assesses the stability and quality of the tear film by measuring how quickly it evaporates. Corneal staining tests identify any existing damage to the eye’s surface caused by dryness.
If a patient is found to have significant dry eye, they are often disqualified from immediate surgery or required to undergo an aggressive dry eye treatment regimen beforehand. Stabilizing the tear film and ocular surface health before the procedure is a prerequisite to mitigate the risk of severe post-operative complications and ensure the eye is in the best condition for accurate measurements and optimal healing.
Vision Correction Options That Minimize Dryness
Patients who are poor candidates for LASIK due to dry eye risk, or who wish to avoid the common temporary dryness side effect, have alternative vision correction procedures available. Photorefractive Keratectomy (PRK) is a surface ablation technique that avoids the creation of a corneal flap, instead removing the outermost layer of the cornea before laser reshaping. Because it does not involve a flap, PRK is often associated with less long-term dryness compared to LASIK, despite having a longer initial recovery period.
Another option is Small Incision Lenticule Extraction (SMILE), a newer procedure that creates a small, lens-shaped piece of tissue within the cornea, removed through a small incision. SMILE requires a much smaller incision than the flap of LASIK, resulting in less disruption to the corneal nerves. This minimal nerve disruption suggests that SMILE may induce less post-operative dryness than LASIK, making it a favorable choice for patients concerned about dry eye.