Contact lenses correct vision by sitting directly on the cornea. For the lens to function correctly and provide comfort, its precise dome shape must align perfectly with the eye’s natural curvature. Inserting a lens backward, or “inside out,” disrupts this fit, compromising both visual acuity and comfort. This improper orientation usually causes noticeable irritation instantly upon placement, signaling the lens needs immediate attention.
Visual and Physical Checks for Orientation
The simplest method to check a soft contact lens is the “bowl test,” performed while the lens rests on the fingertip. Place the lens on the pad of your index finger, ensuring the edges face upward, and view the lens from the side. A correctly oriented lens forms a perfect, smooth, shallow “U” or bowl shape with edges that point straight up. This proper curvature ensures the lens contours naturally to the corneal surface.
If the lens is inverted, the edges will turn slightly outward, creating a shape like a shallow saucer or a wide-brimmed hat. This flaring happens because reversing the lens forces the edges to fold away from the center. Observing the profile from the side is the most effective way to distinguish between the correct, steep “U” and the incorrect, gentle “C” shape.
Another reliable technique is the “taco test.” Place the lens between your thumb and forefinger, pinching it lightly near the center to fold the edges toward each other. A correctly oriented lens will fold inward upon itself, creating a clear taco shape where the edges meet cleanly.
If the lens is inside out when pinched, the edges will resist meeting cleanly and flare outward toward your fingers. This outward resistance signals that the lens curvature is inverted. Perform this check quickly and with minimal pressure to avoid damaging the delicate lens material.
Some lens manufacturers incorporate subtle orientation markings, especially for certain multifocal or toric designs. These markings appear as tiny numbers or letters, such as “123” or “OK,” etched near the periphery. These indicators are often only visible under bright light or with slight magnification. Hold the lens up to a light source while it rests on your fingertip. If the letters or numbers appear correctly and are not reversed, the lens is properly oriented for insertion.
What Improper Insertion Feels Like
When a contact lens is applied inside out, the resulting discomfort is immediate and unmistakable. The inverted, slightly flared edge of the lens rubs against the sensitive tissues of the eyelid with every blink. This constant mechanical friction causes a noticeable stinging or a persistent burning sensation that does not diminish after a few seconds.
The most common complaint is a pronounced foreign body sensation, feeling like an eyelash or speck of dust is trapped under the lens. An improperly fitted lens does not sit flush against the cornea, leading to an uneven distribution of the tear film. This lack of smooth contact triggers the eye’s natural defense mechanism, signaling a disruption.
An inside-out lens often exhibits excessive movement or sliding on the eye’s surface, which contributes significantly to irritation. A properly fitted lens should center quickly and move minimally when blinking. However, an inverted lens often resists centering and may slide noticeably, resulting from the reversed curvature failing to match the eye’s natural dome shape.
While the primary signal is discomfort, vision may also feel slightly off or less crisp. The constant movement and poor centering can cause the visual field to fluctuate noticeably with each blink. The discomfort is usually intense enough to prompt immediate removal before the lens can cause prolonged irritation to the corneal epithelium.
Safe Handling and Reinsertion Steps
If the lens is causing immediate discomfort, the first corrective step is safe removal, which must begin with rigorous hand hygiene. Wash your hands thoroughly with non-cosmetic soap and water, ensuring they are rinsed completely free of any residue. Dry your hands completely with a lint-free towel before touching your eye or the contact lens.
Gently remove the contact lens using the standard pinching technique, taking care to avoid scraping the lens against the cornea. Place the removed lens into your palm, adding a few drops of fresh, sterile contact lens solution to keep it hydrated. This provides an opportunity to re-examine the lens’s orientation using the visual checks described earlier.
If checks confirm the lens was inside out, gently flip it over using your index finger and thumb, ensuring you only touch the edges. Following the flip, rinse the lens generously with a steady stream of fresh, multipurpose or saline solution for several seconds. This rinsing action cleanses any debris, contaminants, or potential microorganisms the lens may have picked up.
After confirming the correct “U” shape and completing the rinse, the lens is ready for reinsertion. Use only fresh, sterile solution for the final rinse and insertion, strictly avoiding tap water or saliva, which can harbor microorganisms. The properly oriented lens should settle quickly and provide immediate relief and comfort upon placement.