Night Blindness
Night blindness is a type of vision impairment also known as nyctalopia. People with night blindness experience poor vision at night or in dimly lit environments. Night blindness itself is not a condition, but the result of an existing eye disorder.
When lighting is dim, the eye must adapt. Although night blindness adversely affects a person’s ability to see in dim light, it does not cause complete blindness. It may create problems seeing road signs while driving at night. It may take a longer time than usual for the eyes to adapt when going from light to dark settings.
What happens to the eye in low or no light?
Your eyes are constantly adjusting to the light. When you are in low or no light, your pupils will get bigger (dilated) so that more light will enter your eye. That light is then received by the retina – tissue in the back of your eye that houses all of the rod and cone cells. Cone cells help you see color. Rod cells help you see in the dark. When those rods are not working well because of a disease, injury, or condition, you can’t see as well or at all in the dark.
Symptoms –
Night blindness is a symptom of an underlying eye condition that results in vision impairment while in dim lighting.
For example, night blindness could prevent someone from being able to see stars at night, or obstacles in a dark room.
To identify night blindness, it is advised that people consider the following questions-
• Is driving at night increasingly difficult?
• Does it take a long time to see in a darkened room after being in the light?
• Is it tricky to recognize faces in dim light?
Other symptoms may also occur with night blindness. The nature of these symptoms will depend on the underlying cause but may include –
• Headaches
• Eye pain
• Nausea
• Vomiting
• Blurry or cloudy vision
• Sensitivity to light
• Difficulty seeing from a distance
Causes –
The problem comes from a disorder of the cells in your retina that allow you to see a dim light. The causes of night blindness include –
• Myopia (Nearsightedness)
• Diabetes
• Glaucoma
• Glaucoma medications that close the pupil
• Cataracts
• Vitamin A deficiency
• Genetic conditions such as Retinitis pigmentosa
• Keratoconus
Diagnosis –
A night blindness test involves a brief eye examination. The eye exam includes the following –
• Tests to measure visual sharpness, pupillary light reflex and the ability to see colors.
• Refraction test to verify the prescription for spectacles or contact lenses.
• Slit-lamp examination to identify structural anomalies in the front of the eye, including conjunctiva, cornea, eyelids, iris, lens and sclera.
• Retinal examination using an opthalmoscope to check for any injury to the structures in the back of the eye, the choroid, retina, vitreous, optic nerve and retinal detachment.
Other tests –
• Electroretinogram
• Visual field tests
Treatment –
Treatment for night blindness will vary depending on the cause.
Treatment may include wearing specific types of glasses or contact lenses, which can help to support the correct vision.
Wearing sunglasses can also protect the eye from ultraviolet light, which can cause further eye damage.
When the cause is a lack of vitamin A, treatment involves adding more vitamin A to the diet.
Eye surgery may be necessary in more severe cases. For example, LASIK is a type of surgery that changes the shape of the cornea to improve vision.
Prevention –
You can’t prevent night blindness that’s the result of birth defects or genetic conditions, such as Usher syndrome. You can, however, properly monitor your blood sugar levels and eat a balanced diet make night blindness less likely.
Eat foods rich in antioxidants, vitamins, and minerals, which may help prevent cataracts. Also, prefer foods that contain high levels of vitamin A.
Certain orange-colored foods are excellent sources of vitamin A, includes-
• Sweet potatoes
• Pumpkins
• Mangoes
• Carrots
• Butternut Squash
• Cantaloupes
Spinach, milk, eggs, green leafy vegetables, etc. also contains vitamin A.
Ayurvedic Perspective –
According to Ayurveda, eye is the seat of pitta dosha. Night blindness is mainly Alochak pitta vikriti. Alochak pitta is a sub type of Pitta dosha.
The procedures works well in this condition is – Akshi Tarpan.
Ayurvedic formulations-
These formulations adds strength to the vision and improves eye luster.
• Amalaki Rasayan
• Saptamrita lauh
• Muktashukti Bhasm
• Mahatriphla ghrita
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