How to Correctly Orient Soft Contact Lenses: The ‘U’ Test and the ‘Taco Test’

After receiving a new pair of soft contact lenses, it can be perplexing to determine if they have been placed correctly. Incorrect orientation can lead to discomfort and vision issues. This guide will provide you with step-by-step instructions and visual cues for using the 'U' Test and the 'Taco Test' to ensure your lenses are properly aligned.

The ‘U’ Test

The 'U' Test is based on the shape the lens takes when held in a specific way, allowing you to easily determine its orientation. Follow these steps:

Step 1: Place the Contact Lens on Your Finger

Hold the lens on your finger with the rounded side facing downward. If you see a 'bowl' or 'cup' shape, the lens is in the correct position. If the lens looks like a dome with the rounded side up, it is flipped inside out. If you find it challenging to keep the lens steady, try placing it on your palm instead.

Step 2: Hold the Lens at Eye Level

Position the lens at eye level, ensuring you view it from the correct angle to avoid illusions. Look at the lens directly from the side to get the best perspective.

Step 3: Check the Appearance of the Lens

When properly oriented, the lens should have a round appearance. Check for flares at the edges. Incorrectly oriented lenses may appear wider at the top with lines that do not appear straight, indicating that the lens is inside out.

The ‘Taco Test’

The 'Taco Test' is an alternative method to determine the orientation of soft contact lenses. Here’s how to perform it:

Step 1: Place the Lens Between Your Forefinger and Thumb

Position your fingers on the inside portion of the contact lens, leaving enough space for you to visualize the edges. Avoid covering or touching the edges with your fingers.

Step 2: Gently Squeeze the Lens

Do not apply too much pressure to avoid damaging the lens. Squeeze gently to observe the shape it makes. If the edges point upwards like a taco, the lens is correctly placed. If the edges squeeze or round outward like the head of a vase, it is inside out and needs to be reversed.

Additional Tips for Ensuring Correct Orientation

Laser Etching Check

Some manufacturers use laser etching to mark numbers on the lens. To verify correct orientation, place the lens on your forefinger, rounded side down, and look for these numbers. If the numbers are right-side up, the lens is correctly aligned. Incorrect orientation may result in smaller numbers or no numbers at all.

Edge Coloring Check

For tinted lenses, check the color of the edges. Correct orientation will generally show a specific color, such as blue or green. If the edges appear in a different color, the lens is likely inside out.

Insertion Experience

If other tests are inconclusive, attempt to insert the contact lens and feel it. Incorrect orientation can cause irritability, itchiness, and discomfort. Remember, even with some discomfort, a clean and correctly inserted lens is generally more comfortable than an incorrectly oriented one.

Conclusion

Properly orienting your contact lenses is crucial for comfortable and clear vision. By using the 'U' Test and the 'Taco Test,' you can easily determine if your lenses are correctly positioned. Additional methods like checking for laser etching and edge coloring can further assist in ensuring optimal lens performance. Practice these techniques and always seek professional guidance if you have any doubts or concerns.