What Is Aniseikonia and How Does It Affect Vision?

Aniseikonia and Its Hidden Effects

Aniseikonia is the term for a difference in image size between your two eyes. Your brain works incredibly hard to reconcile these two differently-sized images, and that effort can be a significant drain on your energy. The most common source of aniseikonia is a difference in the prescription, or refraction, of your two eyes. While you have a natural ability to deal with small image size differences, a more pronounced disparity can create significant challenges.

This often leads to a related condition called anisometropia. While anisometropia is not always an issue when you look straight ahead through the center of your glasses, it becomes a problem as you look through other parts of the lens. As you shift your gaze up, down, or to the side, the images move at different rates, causing discomfort. This is particularly noticeable on the vertical plane, such as when you’re looking up while driving and then down to read something.

The Invisible Symptoms of Visual Strain

The human brain is incredibly resilient, but this resilience comes at a cost. You might not consciously realize that your eyes are struggling to reconcile two different images. Instead, the symptoms often manifest in ways you wouldn’t immediately associate with your vision. You might complain of headaches, general exhaustion, or feeling unusually tired in the afternoon. These are often signs that your brain is expending a lot of energy to make your vision work.

Most optometrists may not identify binocular vision as the source of these symptoms. To truly address aniseikonia, it’s important to consult with a binocular vision specialist. These experts are trained to look beyond a standard eye exam and consider how your eyes work together as a system. Organizations like OVDRA and NORA can help you find a qualified specialist in your area.

A Specialized Solution: The Shaw Lens

The best way to address the discomfort caused by aniseikonia and anisometropia is through freeform optics and specialized lens design. A company called Shaw Lens designs lenses that take the prescription difference between your two eyes and use it to mathematically calculate and predict what the visual challenges will be. By considering the different positions in which you look through the lens, they can design a solution that is tailored to your specific needs. This ensures your brain doesn’t have to work as hard to make your vision clear and comfortable.

Charlie Saccarelli

President, Chadwick Optical

As President of Chadwick Optical, Charlie Saccarelli is the driving force behind the company’s mission to help every patient left behind by the current health care system. Under his leadership, Chadwick has grown from a simple optical lab into a trusted resource for practitioners around the world looking for ways to help the patients that “can’t be helped.” He is a master optician, a father, a bit of a nerd, and a passionate patient advocate who has lectured worldwide on all things optical.