(H53.1, H53.4) Scotoma
A scotoma is common type of vision loss or diminished vision surrounded by comparatively normal vision. A scotoma is also called an island of visual field loss surrounded by relatively normal vision. Nonetheless, a wide range of diseases and traumas can cause a scotoma. For instance, a scotoma can be a sign of optic nerve injury continued later of a stroke or brain injury. Formerly considered not curable, new research developments are useful in treating scotoma.
These are some symptoms associated with scotoma-
- Light, dark or faint spot observed in the center of our vision.
- Call for more light.
- Requirement for more contrast light.
- Not able to identify some colors.
Secondary complications of scotoma leads to enlargement of the blind spot and gradually progresses to macular degeneration.
Scotoma can be detected with the examination called as visual field test. Treatment for scotomas does not exist. Peripheral vision scotomas do not profoundly affect the normal vision.
In case of scotomas caused due to central vision loss, the visuality is severely affected and large magnifications in reading or illuminations and contrast readings are recommended.
Scotomas caused due to brain injury can now be treated with the help of vision rehabilitation methods.
Foremost causes of scotoma are macular degeneration, strokes, brain injuries due to trauma, and some disorders of choroid, retina.
Diseases such as multiple sclerosis, besides injury to the optic nerve are also some of the reasons which can lead to a scotoma.
Scotoma can also be caused due to vascular blockages and the entry of toxins in the body.
Scotoma is also caused due to laser photocoagulation treatment.
Scotoma is differentiated into four types as
- Central scotoma- Visual field loss appears in the central vision and caused due to optic nerve disease or macular disorders.
- Hemianopic scotoma- Visual field loss affects mostly half of the central vision.
- Peripheral scotoma- Visual field loss appears in the peripheral region and caused due to chorioretinal lesions.
- Pareacentral scotoma-Visual field loss near the central region but definitely not the central region.
Scintillating scotoma is mostly observed after symptomatic migraine and was first diagnosed by the physician Hubert Airy. Scotoma starts with spot in the central vision which decreases visual acuity. Further it exaggerates in to arcs which are either white or colored lights. The arc then widens sharply and forms a zigzag pattern. This pattern is called as fortification spectrum. It resembles the fortifications of a fort. Scintillation scotoma can be unilateral or bilateral. It causes difficulty to read and drive to the patients.