Contact lenses provide a solution for vision correction. These thin, flexible devices rest directly on the eye’s surface, conforming to the cornea for clear vision and comfort. Because of their pliable nature, lenses can easily turn inside out during handling, a common issue even long-time wearers encounter. Ensuring the lens is oriented correctly before insertion is paramount for comfortable wear and good eye health.
Identifying the Correct Orientation
The most reliable way to determine if a contact lens is correctly oriented is to examine its shape before placing it into the eye. A properly oriented lens will form a smooth, perfect bowl or half-sphere when placed on the tip of your index finger, with its edges curving gently upward. If the lens is inside out, it will resemble a rimmed soup bowl or a shallow plate, with the edges flaring noticeably outward away from the center.
This subtle difference in curvature can be confirmed using the “taco test,” a tactile method that involves gently folding the lens between your thumb and forefinger. If the edges of the lens roll inward toward each other, like a hard-shell taco, the lens is correctly positioned for insertion. Conversely, if the edges resist folding smoothly and flare outward toward your fingers, the lens is inside out and must be flipped.
Some lens manufacturers include orientation guides, such as micro-engraved laser markings on the lens surface. These markings, often numbers like “123” or letters, will appear correctly readable when the lens is right-side out and viewed under a bright light. If the characters appear backward or reversed, the lens is inside out and must be flipped. Similarly, if your lenses have a light handling tint, the edge color will look vivid and distinct when correctly oriented, but pale or washed out when inverted.
Symptoms of Incorrect Insertion
If a lens is inserted inside out, persistent discomfort is the primary sign. The inverted lens’s flared edge does not sit flush against the cornea, creating a scratchy or gritty sensation, similar to having an eyelash in the eye. This improper fit often leads to an immediate increase in blinking and watering as the eye attempts to clear the irritation.
The lens will move excessively on the eye, or it may pop out, because the reversed curvature prevents it from adhering properly to the tear film. The wearer may also experience blurred or distorted vision, even though the prescription power is correct. Over time, this constant mechanical irritation can cause redness or injection of the conjunctiva, the clear membrane covering the white of the eye.
Steps to Correct and Prevent Future Errors
Remove the lens immediately to stop the irritation. Always begin by washing your hands with soap and water and drying them with a lint-free towel to prevent contamination of the lens and eye. Once removed, the lens should be rinsed with fresh contact lens solution to clean it of any debris.
After cleaning, place the lens on your fingertip and use one of the visual checks, such as the “perfect bowl” side view, to confirm the correct orientation. Gently flip the lens if necessary, re-rinse it with solution, and re-insert it into the eye.
Developing a consistent routine for checking the lens orientation every time will reduce future errors. Always perform the check under bright lighting. If irritation or redness persists for more than a few hours after correcting the lens, remove the lens and consult an eye care professional.