Vision is one of the most relied upon senses, and any impairment to the sense can significantly affect the quality of life and everyday activities. Scotoma is one of the conditions that affects your eyesight by creating a blind spot in your field of vision.
Scotomas are underlying vision problems that lead to the formation of a blind spot in your line of vision. It is also known as a blind spot, or aura, in the vision.
They can be temporary or permanent, depending on type, and they can shift elsewhere in your vision or stay in the same spot.
Types of Scotomas
There are three types of scotomas:
- Scintillating scotoma
- Paracentral scotoma
- Central scotoma
The type and duration of the scotoma usually depends on the underlying cause. You should consult an ophthalmologist or visit a healthcare professional when you notice a blind spot in your vision.
Scintillating scotoma is defined by blurred vision and a recurring sensation of a luminous, or arc-shaped, appearance in front of your eyes. Unlike other scotomas, this type doesn’t have the appearance of a dark spot.
Scintillating scotoma may feel like an aura obstructing your vision. It is also known as teichopsia.
Paracentral scotoma is characterized by a total or partial loss of vision within 10 degrees of fixation. It is not directly in the line of sight, and it can lead to tunnel vision, especially when accompanied by peripheral vision loss.
The number of paracentral scotomas mainly depends on the underlying causative factors, although cases vary from one person to another.
Central scotomas sit directly in your line of vision and can greatly affect your normal functioning. The condition can affect your ability to read standard text size, and tasks like driving and discerning colors and details can be challenging or impossible.
People with this vision defect often look from the side of the eye to compensate for the defect. Additionally, the affected person’s vision can get slightly better in dimly lit places. This is because of the dilation of pupils to allow more light inside the eye.
What Causes Scotoma?
Scotomas can be caused by a combination of varying factors and health conditions, including:
- Diabetic retinopathy
- Optic neuropathy
Some drugs and medications, such as those used to treat chronic heart failure and antiarrhythmic agents, may contribute to ocular symptoms. Some of these drugs can be directly toxic to photoreceptors, cells that convert light into signals the brain can interpret. Discontinuing the drugs that trigged the scotoma can reverse the condition.
This is a medical procedure used in the treatment of varicose and spider veins. The procedure involves injecting a solution into the veins, which forces scarring and redirects blood to alternative veins. Scotomas an develop following the procedure because of reduced blood supply to tissues of the calcarine cortex, a condition known as ischemia.
People with diabetes have an increased chance of developing eye complications. Diabetic retinopathy occurs when you have high blood sugar levels, which can damage the retina. If left untreated, this condition can lead to vision deterioration, central scotomas or blindness.
Glaucoma may contribute to paracentral scotoma because of a build-up of fluids in the front part of the eyes. Glaucoma contributes to the largest cases of permanent blindness globally.
Optic neuropathy develops when there is reduced or interrupted blood flow to the optic nerve in the eye. The resulting effect of optic neuropathy can be sudden vision loss.
What Are Common Symptoms of Scotoma?
Scotoma symptoms depend on the causative factors, but a few common symptoms include:
- Trouble seeing specific details and colors
- Temporary or permanent vision loss
- A single or multiple blind spots
- Headaches and migraines
- Floaters or dots
Who Is at Risk of Developing a Scotoma?
People with the following risk factors stand an increased chance of developing a scotoma:
- Multiple sclerosis
- History of migraines
- High blood pressure
- Cardiovascular disease
- Increased anxiety and stress levels
How Are Scotomas Diagnosed?
Aura in vision can be detected through various methods. These include visual field tests and dilated eye exams.
Visual Field Tests
Also known as a Humphrey visual field test, this procedure involves staring into a bowl-shaped instrument. An eye care specialist performs the procedure and later examines a detailed visual field map of your eyes produced by the machine.
Dilated Eye Exams
Part of the automated visual field test may include dilating your pupils with eye drops. The eye specialist then examines the eye, specifically the optic nerve and retina. This examination can also help determine the type of scotoma.
Are Scotomata Treatable?
Scotoma treatments usually depend on the underlying and causative factors. If a scotoma occurs before a migraine, it will typically go away within an hour or so. Also, scotomas on the outer edges of your vision rarely result in serious vision problems.
Scotoma in the center of your vision cannot be corrected with surgery, glasses or contact lenses. An ophthalmologist may recommend certain aids to augment your decreased vision in such cases. These vision aids may include:
- Use large fonts on your phone and watch faces
- Filters that reduce computer screen glare
- Switching to audiobooks and machine voice readers
- Magnifying glasses, stand magnifiers, and hand-held magnifiers to enlarge text.
The ultimate result of scotomas depends on what type you are diagnosed as having. It’s important to see an eyecare professional when you notice any of signs and symptoms of scotomas.
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Cecocentral Stomata: A Neuro-Opthalmic Revisionist Approach. (June 2015). Investigative Ophthalmology & Visual Science.
Glaucoma in Adults – Screening, Diagnosis, and Management. (January 2021). Journal of the American Association.
Coffee and Doughnut Maculopathy: A Cause of Acute Central Ring Scotomas. (February 2000). British Journal of Ophthalmology.
Patient Awareness of Binocular Central Scotoma in Age-Related Macular Degeneration. (September 2012). Journal of the American Academy of Optometry.
Visual field defects of optic neuritis in neuromyelitis optica compared with multiple sclerosis. (June 2010). BMC Neurology.