Visual disturbances during a migraine.
Visual disturbances, also known as migraine aura, are common for many people who experience migraines. These disturbances typically occur before the headache phase of a migraine attack and can be quite disorienting and sometimes frightening, though they are generally temporary. Visual symptoms can manifest in various ways, often affecting one or both eyes. Here’s a detailed look at the types of visual disturbances experienced during a migraine:
1. Scintillating Scotoma:
One of the most common visual disturbances in migraines is the scintillating scotoma, which is a blind spot surrounded by flickering or shimmering lights. This can develop gradually over several minutes and may expand, often taking on a jagged, zigzag pattern known as a “fortification spectrum,” resembling the walls of a medieval fortress.
- Appearance: A central or peripheral blind spot that grows in size and is surrounded by flashing, flickering, or shimmering lights.
- Color: The lights can be multicolored, but they often appear white, silver, or gold.
- Duration: Typically lasts between 10 to 30 minutes, but can persist up to an hour in some cases.
2. Zigzag Patterns (Fortification Spectra):
This type of visual aura consists of jagged, zigzag lines, often starting in the center of your field of vision and expanding outward. These patterns can appear in various shapes, most commonly resembling the layout of a fortress, hence the name “fortification.”
- Movement: The lines may appear to move, shimmer, or wave, creating a disorienting effect.
- Color: Lines are usually bright, and can sometimes be accompanied by flashes of light or colored spots.
- Location: The pattern can grow from a small point in the visual field and may eventually expand to cover a significant portion of vision before dissipating.
3. Flashing Lights (Photopsia):
Many people experience bright flashes or sparkles of light during a migraine. This can resemble small bursts or sparkles similar to fireworks or stars in the sky.
- Appearance: Sudden flashes of light, often described as twinkling or strobe-like.
- Duration: Flashes can last anywhere from a few seconds to several minutes.
- Triggers: Flashing lights may intensify with head movements or exposure to bright lights.
4. Tunnel Vision:
Tunnel vision is the loss of peripheral vision while central vision remains intact. During a migraine aura, some people may feel like they are looking through a narrow tunnel, with everything outside that tunnel appearing dark or blurry.
- Effect: Only the center of the visual field is clear, while the edges become increasingly obscure.
- Disorientation: This can be especially disorienting, making it difficult to move or focus on tasks.
5. Fortification Figures:
Fortification figures are geometrical visual distortions that appear during a migraine. These shapes often appear as intricate, expanding structures and can resemble mosaics, lattices, or grids.
- Shape: These geometric patterns are often triangular, hexagonal, or grid-like in nature.
- Movement: They may pulse, grow, or shift across the visual field.
- Color: Typically bright white or silver, but may also appear multicolored.
6. Distorted Vision (Metamorphopsia):
This disturbance causes objects to appear distorted in size or shape. Some people may see things as larger or smaller than they actually are (macropsia or micropsia), or straight lines may appear wavy or bent (like looking through a funhouse mirror).
- Macropsia: Objects appear unnaturally large.
- Micropsia: Objects seem smaller than their actual size.
- Warping: Straight lines can appear bent or curved.
7. Kaleidoscope Vision:
In this visual disturbance, people may see their environment as though looking through a kaleidoscope, with fractured or mosaic-like images.
- Appearance: The vision is broken up into multiple, colorful, geometric fragments.
- Movement: The images may rotate or shift, adding to the sensation of disorientation.
- Colors: Bright colors and reflective patterns, often moving or changing in shape.
8. Temporary Blindness:
Some migraine sufferers experience transient vision loss in one or both eyes, which can be partial or total. This can range from brief blackouts in certain areas of vision to complete blindness.
- Duration: Vision loss typically lasts for a short time (under an hour) and gradually returns.
- Laterality: It can affect just one eye (monocular) or both eyes (binocular).
9. Blurry Vision:
Blurry or foggy vision is another common visual disturbance, where the surroundings seem hazy and out of focus. This can make reading, writing, or performing tasks that require precise vision challenging.
- Effect: Things may appear slightly out of focus or covered in a translucent film.
- Fatigue: Eye strain and difficulty focusing can contribute to this symptom.
10. Visual Snow:
Visual snow is a phenomenon where people see tiny flickering dots across their entire visual field, similar to static on a television screen.
- Appearance: The field of vision is filled with grainy or static-like dots.
- Color: The dots are usually black, white, or translucent, but may also be colored.
- Persistence: While typically brief during a migraine, some people may experience this constantly.
11. Shimmering or Sparkling Spots (Phosphenes):
Shimmering or sparkling spots, known as phosphenes, are common. These are flashes of light that appear without any direct visual stimulus.
- Size: The spots can be small, like dots, or larger, resembling streaks of light.
- Movement: They may move or flicker across the field of vision, creating a sense of shimmering.
- Duration: They usually last a few seconds but can recur during the aura phase.
12. Peripheral Vision Loss:
This occurs when the outer edges of the visual field begin to disappear, leaving only the center of the vision intact. This can sometimes be mistaken for tunnel vision, but peripheral vision loss doesn’t involve an actual tunnel effect.
- Effect: The outer edges of vision may gradually become obscured or disappear entirely.
- Laterality: It can affect one side of the field of vision or both sides.
13. Double Vision (Diplopia):
During a migraine, some people may experience double vision, where two images of the same object appear, either horizontally or vertically separated.
- Horizontal Diplopia: Objects appear side-by-side.
- Vertical Diplopia: One image appears on top of the other.
- Effect on balance: This can make walking or coordinating movement difficult.
Duration and Characteristics:
- Onset: Visual disturbances typically start gradually, intensifying over 5-20 minutes.
- Duration: Most visual disturbances last for less than an hour, but some may persist longer.
- Accompanied by other symptoms: Visual auras are often followed by other migraine symptoms such as head pain, nausea, and sensitivity to light or sound.
Impact on Daily Life:
Visual disturbances can severely impair daily activities, including driving, reading, or performing tasks that require concentration. The disorienting nature of these disturbances can also increase feelings of anxiety or panic, especially for individuals who are not accustomed to them.
In conclusion, visual disturbances during a migraine aura are varied and often create a surreal, disorienting experience for those affected. Although they are temporary, they can be unsettling and are a hallmark of the migraine aura phase for many individuals.
