The medical term for visual distortion is “metamorphopsia”. This is to be distinguished from blurred vision (fuzzy or hazy) or a blind spot in the vision (see Blind spots in vision). The best way to determine if vision is distorted is to look at straight lines, like you would see on graph paper, and see if the lines appear bent or wavy. Faces can also look misshapened and sometimes larger or smaller than normal.
There are a few aspects of distorted vision that help to determine what might be the cause:
The speed of onset. Was it sudden or did it develop slowly?
Another is whether it is constant or comes and goes.
The location. Is it in the center or at the side (peripheral) of the vision?
The following are some of the common conditions that can cause visual distortion.
Age related macular degeneration
The vast majority of people with this condition are over 65. Visual distortion can develop in “dry” macular degeneration (See Age Related Macular Degeneration under “Diseases”). This usually develops slowly, is located in the center of vision and is constant. However, this is relatively uncommon in dry macular degeneration. “Wet” macular degeneration is a serious and urgent condition. The visual distortion usually comes on fairly suddenly, within days or weeks, is located in the center of vision and is constant. This condition requires fairly urgent evaluation and treatment. We recommend that this should be evaluated by an ophthalmologist within 72 hours of onset.
This is also a condition that more frequently affects elderly individuals. It occurs when the vitreous gel naturally shrinks with aging and pulls a hole in the central retina (See Macular Hole under “Diseases”). The visual distortion can develop rather quickly, within weeks, but frequently may take months to develop. It is located in the center of vision and is constant. Ultimately, it can cause a permanent central blind spot. Although this is not an urgent problem, and surgical repair is possible even months after the hole develops, it is best to have the symptoms evaluated urgently since there is no way to distinguish these symptoms from those experienced with more urgent conditions, such as “wet” macular degeneration, without an examination.
This condition goes by several different names (See Macular Pucker under “Diseases”). Scar tissue or “fibrosis” develops on the surface of the retina and contracts “puckering” the retina. This can result from retina holes or detachments, inflammation, bleeding in the eye, injuries or even just aging. This almost always occurs slowly, over a period of months or even years. The distortion is constant and in the center of vision. This is not an urgent problem and surgery can be beneficial even months or years after it develops, but urgent evaluation is recommended to rule out other causes.
Central Serous Chorioretinopathy
This is a condition that most commonly affects males between the age or 25 and 55. It is often associated with psychological or physical stress or the use of anti-inflammatory hormones. Fluid accumulates under the retina like a blister and can cause visual distortion and “micropsia” which means that images look smaller in the affected eye. Although this condition frequently resolves spontaneously within a few weeks or months without treatment, it can result in serious, permanent vision loss in some individuals, so it should be evaluated by an ophthalmologist.
Any condition that can cause swelling, or “edema”, in the retina can cause visual distortion. Two of the most common conditions are diabetic retinopathy and retinal vein occlusions. See “Diabetic retinopathy” and “Retinal vein occlusions” under “Diagnosis”.
The important thing to remember is that visual distortion is a potentially serious symptom. Although there are conditions that can cause visual distortion, that are very treatable and do not require urgent treatment, it is not possible to distinguish these problems from those that require urgent diagnosis and treatment. So an ophthalmologist should evaluate the new onset of visual distortion as soon as possible.