Removing contact lenses before surgery is standard protocol, regardless of whether the procedure involves general anesthesia, deep sedation, or local anesthesia. This requirement is a foundational safety measure designed to protect the patient’s vision and ensure optimal care. Ignoring this pre-operative instruction introduces risks ranging from minor eye irritation to serious corneal damage. Understanding the physiological, procedural, and environmental hazards associated with wearing contacts during an operation explains why this rule is strictly enforced.
How Anesthesia Affects Eye Health
One of the most significant dangers comes from the body’s physical response to general anesthesia or deep sedation. When a patient is unconscious, the natural blink reflex is lost, meaning the cornea is no longer lubricated. This lack of blinking, combined with the dry, air-conditioned environment, drastically increases tear evaporation. The resulting severe dry eye can cause the contact lens to adhere tightly to the cornea, making removal difficult post-procedure.
If a lens dries out and sticks, movement during the operation can lead to a painful corneal abrasion—a scrape on the outer layer of the eye causing discomfort and blurred vision. Furthermore, contact lenses limit the amount of oxygen that reaches the cornea. Wearing them for an extended period of unconsciousness can lead to corneal edema, which is temporary swelling of the cornea due to fluid retention.
Impeding Monitoring and Emergency Access
The presence of contact lenses interferes with the medical team’s ability to monitor the patient’s neurological and circulatory status. Anesthesia providers frequently check the eyes to assess pupil size and reaction, which are indicators of brain function and the depth of anesthesia. A contact lens, particularly a tinted or cosmetic one, can obscure or distort this observation, making it harder to recognize subtle changes in the patient’s condition.
In the event of an emergency, quick access to the eye for examination or treatment is paramount. If medical staff needs to administer emergency eye drops or medication rapidly, a contact lens can act as a barrier, preventing the medication from reaching the eye’s surface or getting trapped underneath. Additionally, if a lens were to dislodge beneath the eyelid while the patient is unconscious, it could cause severe irritation or infection, complicating recovery. Removing the lenses ensures the surgical team has an unobstructed view and immediate access for any necessary intervention.
Risks Related to Surgical Equipment and Environment
The surgical environment presents specific risks to contact lens wearers. Operating rooms frequently utilize electrosurgical devices, such as electrocautery tools, to cut tissue and control bleeding. These devices generate electrical current and heat. There is a theoretical concern that a contact lens containing trace metal particles could interact with the electrical field or absorb heat, causing thermal damage to the eye.
A more common issue involves the use of prep solutions, such as iodine, which are used to sterilize the skin around the surgical site. A liquid splash could become trapped between the contact lens and the cornea, causing a chemical burn or severe irritation that would be difficult to flush out while the patient is sedated. Removing the lenses eliminates these external, procedure-specific dangers, ensuring a safer overall setting.
Patient Preparation and Contact Lens Alternatives
Patients who rely on corrective lenses should bring their eyeglasses to the hospital on the day of surgery. Contact lenses should be removed before the patient enters the pre-operative holding area, well before any sedation is administered. Patients must bring their contact lens case and solution so the lenses can be stored safely until after the procedure.
If a patient’s vision is significantly impaired without correction, they should discuss this with the pre-operative nurse and anesthesiologist. The patient can often wear their glasses right up until the moment they are moved into the operating room. For patients with extremely poor vision, the facility may provide temporary, non-corrective lenses. They may also be allowed to reinsert their contacts shortly after they are fully awake and alert in the recovery area, assuming the procedure did not involve the eyes or face.