An inside-out contact lens won’t damage your eye, but you’ll almost certainly feel it. The lens will be uncomfortable, may feel gritty or unstable, and your vision won’t be as sharp as usual. The good news: figuring out whether your lens is flipped is quick, and fixing it takes less than a minute.
What an Inside-Out Lens Feels Like
Contact lenses are molded to match the curvature of your eye. When a lens is inverted, that curvature is reversed, so it no longer sits flush against your cornea. The result is a lens that shifts around, feels like something is caught under it, and doesn’t stay centered the way it should.
Common signs that your lens is in backwards:
- A gritty or scratchy sensation that doesn’t go away after blinking a few times
- The feeling that the lens is sliding around on your eye, especially when you blink
- Watery eyes, as your eye tries to flush out what it perceives as an irritant
- The lens pops out easily, sometimes just from blinking hard
- Slightly blurry or unstable vision, since the lens can’t hold its proper shape against your eye
If you’ve worn contacts for a while, you’ll usually notice something is off within seconds of inserting the lens. For newer wearers, it can be harder to tell because general contact lens discomfort is still unfamiliar. A useful rule of thumb: if one eye feels fine and the other feels irritated with the same brand and prescription, the uncomfortable lens is likely inside out.
The Taco Test
The most reliable way to check your lens before you put it in is the taco test. Place the lens on your palm and gently fold it in half, bringing the edges together like you’re making a tiny taco. If the edges come together smoothly and curve inward, forming a neat closed shape, the lens is oriented correctly. If the edges flare outward and resist closing, the lens is inside out.
This takes a little practice. With thin, flexible lenses, the difference between correct and inverted can be subtle. Try it a few times with a fresh lens so you know what “right” looks like before you’re rushing through your morning routine.
The Side Profile Check
If folding the lens feels awkward, you can also check by placing it on the tip of your index finger and looking at it from the side at eye level. A correctly oriented lens looks like a smooth bowl with edges that curve straight up. An inside-out lens looks more like a shallow plate or soup bowl, with edges that flare outward. Some people describe the correct shape as a “U” and the inverted shape as more of a flat-bottomed “U” with lips that tilt out.
Certain lens brands also print tiny numbers or letters near the edge of the lens. If you can read them normally, the lens is right-side out. If they appear reversed or mirrored, flip the lens.
How to Fix It
If you realize your lens is inside out while it’s still on your finger, simply flip it. Push gently on one edge so it inverts, then confirm the shape looks correct before inserting.
If the lens is already in your eye, take it out and start over. Wash and dry your hands first. Look up, then slide the lens down onto the white part of your eye using one fingertip. Gently pinch it between your thumb and forefinger to remove it. Once it’s out, place it in your palm, add a drop or two of contact lens solution, and rub it in a straight back-and-forth motion to clean off any debris or oils. Then flip the lens to the correct orientation, rinse it again with solution, and reinsert.
For reinsertion, hold your upper lashes (not the lid) with one hand to keep yourself from blinking. Pull your lower lid down with the hand holding the lens on your fingertip. Focus on a steady point with your other eye, place the lens directly on the center of your eye, and release your lids only after the lens is in place.
Why It Happens So Often
Modern soft contact lenses are extremely thin and flexible, which makes them comfortable but also makes it easy to flip them without realizing it. It commonly happens when you’re taking lenses out of the case, when a lens folds on itself during removal, or when you rub a lens between your fingers while cleaning it. Getting in the habit of checking every lens before insertion, either with the taco test or the side profile check, saves you from the discomfort of figuring it out the hard way once it’s already on your eye.