The retina (pronounced: RET-nuh), the innermost of the three layers, lines the inside of the eyeball. The retina is a soft, light-sensitive layer of nervous system tissue. The optic nerve carries signals from the retina to the brain, which interprets them as visual images.

Signs and symptoms of nervous system disorders

• Persistent or sudden onset of a headache.
• A headache that changes or is different.
• Loss of feeling or tingling.
• Weakness or loss of muscle strength.
• Loss of sight or double vision.
• Memory loss.
• Impaired mental ability.
• Lack of coordination.

cerebrum

The Central Nervous System is the integration and command center of the body. It consists of the brain, spinal cord and the retinas of the eyes.

We find that a brain signal associated with moving the eyes appears to play a role in resetting visual analysis on each fixation, a process that may aid in parsing the neural signal.

Sit in vajrasana and place a lit candle at some distance from yourself at eye level. Fix your gaze at the tip of the candle’s wick and look at it. Try not to blink and keep the gaze as steady as possible. Allow the tears to flow, if they come.

facial nerve

When focused light is projected onto the retina, it stimulates the rods and cones. The retina then sends nerve signals are sent through the back of the eye to the optic nerve. The optic nerve carries these signals to the brain, which interprets them as visual images.

The eye is the only part of the brain that can be seen directly – this happens when the optician uses an ophthalmoscope and shines a bright light into your eye as part of an eye examination. And if pressure in the brain increases, perhaps due to a brain tumour, we can see this as a swelling of the optic nerve.

But we don’t ‘see’ with our eyes – we actually ‘see’ with our brains, and it takes time for the world to arrive there. From the time light hits the retina till the signal is well along the brain pathway that processes visual information, at least 70 milliseconds have passed.

The researchers said that in general, poor vision reduces a person’s ability to participate in activities that stimulate the brain. They also noted that vision had a stronger influence on brain function than the reverse.

Call your doctor if you experience any of the following:

• Change in iris color.
• Crossed eyes.
• Dark spot in the center of your field of vision.
• Difficulty focusing on near or distant objects.
• Double vision.
• Dry eyes with itching or burning.
• Episodes of cloudy vision.
• Excess discharge or tearing.

Types of Neuro-Visual Disorders

• Optic Neuropathies. Damage to the optic nerves can cause pain and vision problems, most commonly in just one eye.
• Optic Neuritis.
• Giant Cell (Temporal) Arteritis.
• Chiasm Disorders.

The most common vision problems related to head injuries include blurred vision, double vision and decreased peripheral vision. Patients can also experience a complete loss of sight in one or both eyes depending on the severity of the injury.

Physical symptoms of brain damage include:

• Persistent headaches.
• Extreme mental fatigue.
• Extreme physical fatigue.
• Paralysis.
• Weakness.
• Tremors.
• Seizures.
• Sensitivity to light.

After relatively minor trauma, people can also experience headaches or sensitivity to light, and words on a page may appear to move. More serious vision problems can also result from a blow to the head or other head injury. These can include: Retinal detachment.

Patients with head trauma often have multiple and extensive intracranial lesions that may involve the optic pathways and result in various homonymous visual field defects or bilateral visual loss (cerebral blindness).

When the optic nerve is injured, there are tears and swelling in the affected area that causes the nerve cells to die. This type of injury is called traumatic optic neuropathy, or TON, and results in irreversible vision loss.

Blunt force and penetration are the primary cause of eye trauma. Blunt trauma causes the eye to suddenly contract and expand. That is one of the causes of temporary or permanent blindness.

A person with total blindness won’t be able to see anything. But a person with low vision may be able to see not only light, but colors and shapes too. However, they may have trouble reading street signs, recognizing faces, or matching colors to each other. If you have low vision, your vision may be unclear or hazy.

Just as blind people do not sense the color black, we do not sense anything at all in place of our lack of sensations for magnetic fields or ultraviolet light. We don’t know what we’re missing. To try to understand what it might be like to be blind, think about how it “looks” behind your head.

While there is no cure for blindness and macular degeneration, scientists have accelerated the process to find a cure by visualizing the inner workings of the eye and its diseases at the cellular level.

Acquired blindness was associated with relatively preserved vestibulo-ocular responses and the ability to initiate voluntary saccades and smoothly track self-moved targets. Certain features of the eye movements of the blind are similar to those due to cerebellar dysfunction.

First of all, it is totally disrespectful, but common sense would also tell the wearer, it is difficult to see inside without removing them and therefore, one could easily trip and fall. How embarrassing that would be. Secondly, it is extremely rude to carry on a conversation with anyone wearing sunglasses indoors.

Those who suffer from dry eyes, or whose pupils have been dilated in the course of a medical examination, are sometimes advised to shield them from glare. But for the vast, vast majority, wearing sunglasses indoors is an affectation. And it’s one that can draw a strong reaction from bystanders.

Wearing sunglasses at night further reduces the amount of light reaching the retina, and therefore is not recommended under any circumstances — especially when driving at night — because it will worsen darkness-related visual impairment.

Sunglasses. When you see people in mourning or funerals on tv you will often see people wearing sunglasses sometimes to conceal the tears in their eyes. Sunglasses are appropriate especially if outdoors. Follow the same rule in regards to minimalism and modesty.