Have you ever felt like your vision is just off? Things just don’t quite look right including distorted or simply blurr? In normal eyes, vision can be disrupted due to small changes within our tear film or other transient problems. These can be caused by chronic conditions like dry eye or more transient ones such as a piece of grit in the eye. People with an amblyopic eye often complain that things just don’t look right out of that eye, even after treatment and despite technically seeing very well.
In the most common cases of amblyopia, people see 20/20 out of one eye but cannot see that well out of the other. When asked about using their poorer eye, they respond saying they “just don’t see right out of this eye“, even when they can see 20/25 or 20/30. Both of these visual acuities are well within legal driving limits and many normal people chose not to wear glasses to correct for these small amounts of blur. However amblyopic people have never developed the ability to fully use their visual system and even at those levels often feel their vision is not correct.
For example, I have a good friend who is amblyopic in one eye, she had lasik done and now sees 20/25 out of her amblyopic eye, a great result. The problem lies in that she now can only see 20/30 our of her “normal” eye without glasses or contacts. Without glasses she literally sees better out of her amblyopic eye. She is not happy with this result despite technically seeing very well. She tells everyone things don’t look right without her contacts. Specifically for her she cannot recognize faces across a room. In this instance her brain has never learned to take the information from her amblyopic eye and feed it into the section of the brain which allows us to recognize people.
Doctors have similar results in the exam room with amblyopic eyes. For instance, when reading a visual acuity chart an amblyopic eye will often read three-fourths of a 20/40 line, none of a 20/30 line and half of a 20/25 line. Objectively this doesn’t make any sense as each subsequent line is smaller, so how can they read half of a smaller line and not any of a larger line? Amblyopic eyes do not process information the same way normal eyes do. Incidentally this is partly why this type of exam takes significantly longer than others. Visual acuities need to be checked and rechecked because results are often inconsistent.
Faces and visual acuity are two good examples of how amblyopia changes vision, but there are many others. Driving, motion, and contrast can all be affected in amblyopic individuals. Vision is much more than simple visual acuity, especially in amblyopic individuals.