Soft contact lenses are flexible, making them comfortable to wear but also susceptible to being accidentally turned inside out during handling. This is a common occurrence, especially for new wearers, happening when the lens is reversed so that its intended concave surface faces outward. The lens is engineered with a specific curvature designed to fit the cornea. When this dome is disrupted, the lens no longer sits correctly on the eye. While wearing a lens inside out does not cause permanent damage, the incorrect orientation immediately causes a noticeable difference in comfort and fit.
Distinct Sensations of an Inside-Out Lens
The most immediate sign that a contact lens is inside out is the distinct sensation of persistent irritation. This feeling is often described as having an eyelash, a speck of dust, or grit trapped beneath the lens that does not flush away with blinking or tears. The discomfort arises because the reversed, slightly flared edge of the lens rubs against the delicate conjunctiva and the inner surface of the eyelid.
This misalignment prevents the lens from adhering smoothly to the cornea, leading to excessive movement and instability. Wearers often report the feeling that the lens is sliding or moving around too much when they blink. The compromised fit can also interfere with the natural tear film, causing mild symptoms like watery eyes or a slight stinging sensation upon insertion. Vision may become slightly blurry or unstable as the lens shifts across the pupil. Experiencing these symptoms immediately after insertion indicates the lens needs to be removed and checked.
Visual Confirmation Methods
Once the lens is removed, there are several visual and tactile checks to confirm its orientation. The most reliable visual method is the side-view check. The lens is placed on the tip of a clean, dry index finger with the edge facing upward. When viewed from the side, a correctly oriented lens forms a smooth, symmetrical, cup-like shape with the edges pointing straight up. Conversely, an inside-out lens appears more like a shallow bowl with a noticeable rim, as its edges flare distinctly outward.
Another widely used method is the “Taco Test,” which relies on the lens’s material memory and curvature. To perform this, gently pinch the lens between the pads of your thumb and forefinger, folding it slightly in half. If the lens is correctly oriented, the edges fold inward toward each other, resembling a hard-shell taco. If the lens is inverted, the edges bend outward toward your fingers, taking on a shape more like a wide bowl.
Some modern lenses incorporate small laser-etched indicator markings to simplify the check. These markings are typically numbers, such as “123,” or letters located near the edge of the lens. When the lens is resting on your fingertip, if the marking is readable from left to right, the lens is right-side out. If the marking appears backward or mirrored, the lens is inside out and requires flipping.
Correcting the Position and Reinsertion
The process of correcting an inside-out lens begins with meticulous hand hygiene, washing thoroughly with soap and drying with a lint-free towel to prevent contamination. Once the lens is confirmed to be inverted, gently flip it by placing it in your palm and using the pad of a clean finger to turn it over. Use the soft pad of the finger, avoiding fingernails, which can tear the delicate lens material.
After flipping, the lens must be thoroughly cleaned and rinsed with a fresh, approved multipurpose contact lens solution. This step removes any debris or microorganisms transferred during handling. Never use tap water, bottled water, or saliva for rinsing, as these contain impurities and microbes that increase the risk of eye infection. Once cleaned, the lens can be placed back on the fingertip, checked one last time for the correct cup shape, and safely reinserted.