When one eye hurts with identical contact lenses, the first step is to check for a foreign body

When one eye feels off, but the lenses sit the same on both eyes, the instinct is to start with what’s familiar. But in eye care, one small clue can save a lot of distress for the patient. Here’s a practical, human-centered approach that keeps the patient safe while you sort out what’s really happening.

First things first: the first move is to check for foreign bodies

Let me ask you this: if a patient complains of discomfort in one eye, is it equally likely that the problem lives in the lens or in the eye itself? The answer is no, not always. The eye is a delicate, responsive organ, and a tiny speck of dust or a splinter of metal can turn a simple wear situation into a painful experience in minutes. When parameters are identical for both eyes, the prudent, immediate action is to inspect the affected eye for any foreign material.

This step is more than a formality. Foreign bodies can cause irritation, tearing, photophobia, gritty sensation, and even corneal abrasion if left unchecked. Finding and removing a foreign body often brings rapid relief. It also helps you rule out a straightforward, eye-origin issue before you start tweaking lenses or prescriptions. It’s classic “first rule of thumb” care: rule out the obvious, then move on to more subtle possibilities.

How to approach the examination calmly and effectively

• Start with a focused history

A quick, two-minute chat can pay off. When did the discomfort begin? Was there an eye splash or something irritating in the environment—dust, chlorine, or a windy day? Has the patient worn a new lens or tried a different lens solution recently? Does the discomfort worsen at the end of the day or with blinking? These questions help you gauge whether the problem might be a surface irritant or something more persistent.

• Inspect with the right tool set

A slit lamp is your best friend here. Under high magnification and good illumination, you can spot tiny foreign bodies on the cornea, conjunctiva, or under the upper lid. If you don’t have immediate access to a slit lamp, thorough exterior inspection and patient blink follow-up can still guide you, but a slit lamp makes the search more reliable.

• Use fluorescein thoughtfully

Fluorescein staining reveals corneal surface integrity. When you apply a small amount and use a cobalt blue filter, you’ll see any corneal abrasions or compromised epithelium. A foreign body can cause an abrasion, and sometimes the dye will highlight areas of microtrauma that aren’t obvious to the naked eye. If you detect a defect, proceed with removal of the foreign body if safely possible and then recheck with staining.

• Remove gently if you identify a foreign body

For a superficial object on the cornea or conjunctiva, you might remove it with a sterile moistened cotton-tipped applicator or a micro-sterile blade, depending on your training and the device you trust. The key is to use gentle, steady motions, not force. If the foreign body is on the lens surface, avoid pressing the lens into the eye; instead, address the eye first and then reassess the lens fit afterwards.

• Irrigate when appropriate

If the object is loose, a gentle saline irrigation can dislodge it. Irrigation is a safe, effective way to clear the ocular surface and can be a relief for the patient. Just be mindful of the patient’s comfort and the corneal surface condition—irrigation should be calm, controlled, and not rushed.

• Reassess after removal

Once the foreign body is gone, recheck the eye for surface integrity and residual irritation. If the eye looks clear and the patient reports immediate relief, you’ve likely solved the problem. If discomfort lingers, you’ll have to loop back to lens assessment with fresh eyes.

If the eye is clean but discomfort persists, what comes next?

This is where the clinical mindset shifts from “eye-first” to “lens-check.” If you’ve ruled out a foreign body and the patient still isn’t comfortable, you begin a focused reassessment of the contact lens fit and the wearing experience. There are a couple of plausible routes to explore, depending on what you observe.

• Revisit lens fit and edge behavior

Even when parameters are identical, the lens edge can interact differently with the eye. Lens misalignment, edge lift, or a slight tear in the cornea due to blinking can produce discomfort that feels like a problem with the lens, not the eye. Check for edge lift or centration issues, and verify that the lens is centered over the cornea without bearing on the lid margin. A quick trial with a different lens shape or a slightly altered edge design (if available) can clarify whether the fit is the culprit.

• Evaluate lens material and care

Material properties influence how a lens interacts with the tear film. A lens that feels dry or sticky could produce irritation even with perfect fitting. Review the wear time, cleaning regimen, and lens conditioning products. Is the patient using a solution that’s compatible with the lens material? Are there deposits or a film that can irritate the ocular surface? Sometimes a simple change in care routine or a different lens brand or modality helps a lot.

• Look for surface deposits or micro-abrasions

Lipid or protein deposits can irritate the eye, especially toward the end of a wear cycle. If deposits are evident, a more thorough cleaning or a replacement schedule adjustment might be in order. If a micro-abrasion is suspected, fluorescein staining can reveal surface irregularities—this is another moment where your observation skills make a real difference.

• Consider environmental and systemic factors

Dry eye, allergies, and environmental stressors (heaters in winter, air conditioning in offices, or dusty clinics) can amplify discomfort for contact lens wearers. A quick discussion about hydration, screen time, and environmental changes can uncover non-lens causes that still impact the patient’s experience with lenses.

A practical flow you can adapt to daily practice

• Step 1: Ask about onset, triggers, and prior steps taken.

• Step 2: Inspect the eye for foreign bodies with a slit lamp; use fluorescein if needed.

• Step 3: If a foreign body is found, remove it and re-evaluate.

• Step 4: If the eye is clear but pain remains, examine lens fit, edge behavior, and surface conditions.

• Step 5: Review care routines and environmental factors; consider a lens material or design change if indicated.

• Step 6: Schedule a follow-up to ensure complete resolution and confirm comfort with the current setup.

Common pitfalls to avoid

• Jumping to lens changes without ruling out ocular causes. It’s easy to think “the same lenses, same parameters, must be the issue,” but that assumption can miss a simple eye problem you could fix on the spot.

• Overlooking the eyelids and lash-related irritants. A misdirected blink or a lash that rubs the cornea can mimic lens discomfort.

• Underestimating dry eye influence. Even a well-fitted lens can irritate if surface tears are compromised.

• Skipping a follow-up. Comfort can return slowly, or a minor issue can recur; a quick check-in helps keep the patient confident in your care.

Real-world nuance that makes the difference

Let’s keep this human. The patient isn’t a bundle of numbers; they’re someone who wants to see clearly and feel comfortable. When you start with a simple, concrete action—checking for a foreign body—you’re signaling that you respect their experience and you’re prepared to address what’s most likely causing the discomfort. That trust matters, and it often makes the difference between a patient who simply wears lenses and a patient who loves wearing them.

If the patient is new to contact lenses or returning after a period of discomfort, a transparent plan helps too: explain what you’re looking for, what you’ll check next, and how you’ll follow up. You don’t have to be overly clinical to be credible; you’re guiding them through a careful, stepwise approach that prioritizes safety, comfort, and clear vision.

A few supportive notes you can carry into any patient interaction

• Keep language accessible. Use plain terms for what you’re seeing (for example, “this area looks a bit irritated” instead of “epithelial disruption” unless the patient is curious about the science).

• Offer reassurance without oversimplifying. It’s common to feel anxious about eye discomfort; acknowledging that you’re going to take it step by step helps.

• Build a quick reference you can rely on. A short checklist for unilateral discomfort helps you stay consistent and thorough, especially on busy days.

• Record what you observe. A concise note about whether a foreign body was found, whether irrigation was performed, and what the next plan is every time you see a patient helps with continuity of care.

Closing thought: care comes full circle

Discomfort in one eye with identical lens parameters is a cue to slow down and listen to the eye itself. The very first move—checking for a foreign body—often delivers the fastest relief and clears the path for the next steps. If nothing is found, you still have a clear, methodical route to reassess fit, material, and care. That balanced approach—eye-first, lens-second, patient always—keeps you aligned with how eye care should feel: responsive, reliable, and human.

If you ever wonder how to keep the conversation efficient yet warm, remember this: a patient’s eye may speak softly, but with the right checks and a calm demeanor, you’ll hear the message loud and clear, and you’ll be able to respond with care that makes sense to them. After all, every eye deserves a clear view—and every clinician deserves a steady, thoughtful path to get there.