Skip to main content

Night Blindness

 

Patients who suffer from nyctalopia, or more commonly known as night blindness, experience poor vision during the night or in poorly lit environments. It is a form of vision impairment and occurs as a symptom of numerous congenital (present from birth) and inherited retinal diseases or as a result of vitamin A deficiency.


Vitamin A deficiency contributes to night blindness by making the cornea very dry, thus damaging the retina and cornea. As a result, the blood vessels running through these areas are affected. These veins carry neurons between the optic nerve and the brain. Hence, neurons die when the veins are damaged, and the brain does not receive visual information. 


The effects of a damaged retina and cornea is exacerbated at night as the near absence of blue light renders one colour blind. This effect contributes to “night blindness”.


Sources:

https://www.webmd.com/eye-health/night-blindness

https://www.optometrists.org/general-practice-optometry/what-causes-night-blindness/night-blindness-treatments-and-prevention/

https://www.britannica.com/science/night-blindness


Comments

Post a Comment

Popular posts from this blog

Parkinson's Disease

Parkinson’s disease is a progressive nervous system disorder that affects one’s movements. Parkinson’s disease signs and symptoms are different for every individual and may go unnoticed in the early stage. Symptoms typically start on one side of the body and remain worse on that side even after the symptoms begin appearing in both sides of the body.  Generally, the symptoms of Parkinson’s disease include tremors, slowed movement, rigid muscles, impaired posture and balance, loss of automatic movements such as blinking or swinging of arms when walking, and speech and writing changes.  Parkinson’s disease occurs when neurons in an area of the brain that controls movement becomes impaired or dies. These neurons normally produce dopamine. As more neurons become impaired or die, the amount of dopamine produced in the body is reduced significantly, causing the movement problems associated with Parkinson’s disease.  People with Parkinson’s also lose the nerve endings that produc...
Post a Comment
Read more

Tinnitus

Tinnitus is a hearing condition often described as ringing in the ears. Tinnitus can also cause other types of noise in your ears such as: buzzing, roaring, clicking, hissing and humming.  The pitch heard from tinnitus can vary from a high squeal to a low roar, this can affect the patient’s ability to detect tinnitus from external sounds Tinnitus can develop gradually over time or occur suddenly. It is often associated with: age-related hearing loss, inner ear damage, earwax build-up and middle ear infection However, one in every three people with tinnitus doesn't have any obvious problem with their ears or hearing. Sources: https://www.mayoclinic.org/diseases-conditions/tinnitus/diagnosis-treatment/drc-20350162 http://www.webmd.com/a-to-z-guides/understanding-tinnitus-basics
Post a Comment
Read more

Pompe Disease

Pompe disease is a rare genetic condition where the body is unable to break down complex sugars. This is due to a deficiency in an enzyme called acid alfa glucosidase (GAA). Mutations in the GAA gene causes this disorder and results in a build up of glycogen in cells.  Pompe disease can appear in patients from within a few months of birth, at about 1 years old and even during the teenage years.  Those with Pompe disease usually inherit the disease from their parents. However, the allele for the disease is recessive, and may not be expressed in the parents. This disease is typically associated with weak muscles, poor muscle tone and an enlarged liver. However, there are many complications with regards to the respiratory system and motor skills which can also develop.  Enzyme replacement treatment is used for all Pompe patients. A drug called aglucosidase alfa is given intravenously, which acts as a replacement for GAA. Sources: https://my.clevelandclinic.org/health/disease...
Post a Comment
Read more