Potential Side Effects of Prism Glasses

Are Your Prism Glasses Making Your Eyes Worse? The Hidden Risks of Increasing Prism for Eye Strain

Potential Side Effects:

• Increasing frequency Eye turn (Strabismus): Eye turns more often

• Increasing magnitude of Eye turn  (Strabismus): Eye turns further

• Suppression of an Eye: the Brain starts to ignore one eye

• Decrease Depth Perception

• Decreased Peripheral Vision

If you’ve been prescribed prism lenses to help with eye strain, especially while working on a computer, tablet, or smartphone, you’re not alone. But what if we told you that increasing prism over time could actually make your vision problems worse—not better?

We’re seeing more and more patients in our clinics with a similar story: ongoing eye strain while using screens, followed by increasing amounts of prism added to their glasses. What starts as a mild visual discomfort can escalate into a serious misalignment of the eyes—sometimes even full-blown strabismus (a constant eye turn).

Let us explain why this happens—and what you can do about it.

Case Study: When Prism Made Things Worse

A 54-year-old male came to our clinic recently with over 45 prism diopters (PD) of constant esotropia—a severe inward turning of the eyes. He had spent years working as an engineer with long hours of screen time. About eight years ago, his eye doctor prescribed base-out (BO) prism to help relieve his eye strain, a sign of esophoria, or inward pulling of the eyes under stress.

At first, the prism seemed to help—but every year, the prescription increased.

📷 He showed us photos from before he started wearing prism. His eyes were perfectly aligned.

Eventually, the eye strain worsened, the esophoria progressed to esotropia, and his doctor told him he needed more prism than could be safely placed in glasses. That’s when he turned to us. After undergoing vision therapy, his eyes are now nearly perfectly aligned—without relying on prism.

What Prism Really Does

Prism doesn’t fix the cause of your eye strain. It simply moves the image of the object you’re looking at—not the object itself. This can temporarily relieve symptoms by tricking your brain into seeing things more comfortably. But here’s the problem:

👉 Every time prism is increased, you’re feeding your brain more false visual information.

Over time, your brain adapts to this distorted input, which can actually make the underlying misalignment worse. The result? A stronger reliance on prism… and eventually, a level of eye misalignment (strabismus) that didn’t exist before.

The Vicious Cycle of Prism and Screen Strain

Many people today experience eye strain from extended time on digital devices. When screen fatigue is caused by binocular vision dysfunction—a problem with how the eyes work together—prism may provide short-term relief but long-term harm.

Symptoms of binocular vision dysfunction include:

• Eye strain while reading or on screens

• Headaches or fatigue from visual tasks

• Intermittent double vision or eye drifting

• Difficulty focusing or tracking

• Neck tension from tilting your head to compensate

If you've been prescribed prism and your symptoms return—or worsen—each year, your eyes may be adapting poorly to the prism. This is especially risky if your prism prescription is increasing over time.

Vision Therapy: The Right Solution for Eye Strain and Esophoria

Instead of masking the symptoms, vision therapy addresses the root cause of binocular vision dysfunction. This customized, evidence-based therapy retrains the visual system so your eyes can align, team, and focus naturally—without the need for increasing prism.

We’ve helped patients of all ages, from toddlers to those in their 80s, recover proper eye alignment and regain visual comfort. And best of all? Many are able to reduce or eliminate their reliance on prism entirely.

What Should You Do If You Wear Prism Glasses?

If your eye strain is getting worse, or your prism prescription keeps increasing, it’s time to re-evaluate the approach.

✅ Get assessed by a developmental or neuro-optometrist who specializes in binocular vision

✅ Ask if you’re a candidate for vision therapy

✅ Don’t wait until the eye misalignment becomes permanent

Prism can serve a purpose—but it should be prescribed strategically and temporarily, not as a crutch. Long-term use without treating the cause can lead to unintended and often serious visual consequences.

Still Struggling with Eye Strain? We Can Help.

Whether you’re just beginning to feel the effects of screen fatigue or you’ve been on prism lenses for years, we’re here to help you find a solution that restores comfort and clarity—without compromising your long-term visual health.

✅ Book online to schedule a comprehensive binocular vision evaluation and learn if vision therapy is the right step for you.