Disorders affecting the optic nerve

Question 1

Disorders that can affect the optic nerve

Answer 1

Glaucoma

Papilledema

Optic neuritis

Optic nerve atrophy

Optic nerve neuropathy

Macular degeneration

Diabetic neuropathy

MS

Hypertension

B12 deficiency

Question 2

Glaucoma

Answer 2

Where the optic nerve, which connects the eye to the brain, becomes damaged

Increased pressure in the eye

Cause:
– elevated eye pressure happens as a result of a build-up of fluid that flows throughout the inside of the eye. Known as AQUEOUS HUMOUR
—- usually drains through the trabecular meshwork
—- when the eye creates too much fluid or the drainage system doesn’t work properly, eye pressure may increase.

Different types of glaucoma:
- open-angle glaucoma:
— most common form, drainage system doesn’t work properly which can lead to an increased eye pressure
– symptoms:
—- no symptoms in early stages
—- gradually, patchy blind spots in your peripheral vision
—- later stages- difficulty seeing things in central vision

• angle-closure glaucoma:
  — caused when iris bulges, and either partly or completely blocks the drainage angle
  – symptoms:
  —- severe headache
  —- severe eye pain
  —- nausea or vomiting
  —- blurred vision
  —- halos or coloured rings around lights
  —- eye redness
• normal-tension glaucoma:
  — there is raised intraocular pressure
  – symptoms:
  —- no symptoms in early stages
  —- gradually, blurred vision
  —- loss of slide vision in later stages
• glaucoma in children:
  — blocked drainage, injury or an underlying medical condition may cause optic nerve damage

Risk factors:
– age over 55
– high internal eye pressure
– family history of glaucoma
– corneas that are thin in the centre
– eye injury or certain type of eye surgery

Question 3

Papilledema

Answer 3

When a disc swelling is secondary to increase intracranial pressure

When pressure in your brain makes your optic nerve swell

Causes:
– when cerebrospinal fluid builds up where your optic nerve and the central retinal vein travel between your brain and your eye nerve.
—- this area is known as the subarachnoid space

– brain swelling can be caused by a number of injuries and conditions:
—- traumatic injury to the head
—- not having enough red blood cells or haemoglobin (anaemia)
—- CSF build-up in your brain
—- brain bleeding
—- brain inflammation
—- brain tissue inflammation
—- high blood pressure
—- brain tumour

Symptoms:
– early symptoms:
—- changes to vision (blurring, double vision, seeing flashes)
—- nausea
—- throwing up
—- having abnormal headaches
—- hearing ringing or other noises in your ears

Question 4

Optic neuritis

Answer 4

Inflammation/swelling of the optic

Causes:
– exact cause is unknown, believed to be an autoimmune problem
– autoimmune conditions associated with optic neuritis:
—- multiple sclerosis
—- neuromyelitis optica
—- myelin oligodendrocyte glycorotein antibody disorder

Risk factors:
– age- 20-40 more
– sex- women more likely
– race
– genetic mutation

Symptoms:
– pain with eye movement
– temporary vision loss in one eye
– loss of colour vision
– flashing lights

Question 5

Optic nerve atrophy

Answer 5

Degeneration/gradual damage of the optic nerve

Causes:
– poor blood flow (ischemic optic neuropathy)
– glaucoma
– brain tumour
– crania, arteritis
– MS
– stroke

Symptoms:
– dim and reduces field of vision
– ability to see fine detail will be lost
– colours will seem faded
– pupil will less able top react to light

Question 6

Optic nerve neuropathy

Answer 6

Sudden loss of vision

Most common in people over the age of 50

Causes:
– normally ischemic optic neuropathy (optic nerve atrophy)
– nutritional deficiencies including a lack of vitamin B12, can be a common cause

Symptoms:
– seeing flashing or flickering lights when moving the eyes
– colours may appear less bold or vivid than they normally do
– you may lose vision in one eye, either partially or fully
– pt’s often experience pain in the face and eye socket
– a general loss of peripheral vision
– pain inside the eyes

Question 7

Macular degeneration

Answer 7

Common condition that affects the middle part of your vision.

It happens when ageing causes damage to the macula

Usually affects people in their 50s and 60s

Symptoms:
– affects the middle of your vision

Question 8

Diabetic neuropathy

Answer 8

Eye condition that can cause vision loss and blindness in people that have diabetes.

It affects the blood vessels in the retina

Cause:
– caused by a high blood pressure. Over time, having too much sugar in your blood can damage the retina
– the damage to the eyes starts when sugar blocks the tiny blood vessels that go to your retina, causing them to leak fluid or bleed.
—- this may cause the eyes to create new blood vessels that dont work as well. these new blood vessels can leak or bleed easily.

Symptoms:
– early stages usually dont have any symptoms

– Some people detect changes in their vision, like trouble seeing faraway objects. These changes may come and go.

Later stages:
– blood vessels in the retina start to bleed into the vitreous
– if this happens you may see dark, floating spots or streaks that look like cobwebs
– without treatment, scars can form in the back of the eye. Blood vessels may also start to bleed again, or the bleeding may get worse.

Other problems diabetic retinopathy can cause:
– diabetic macular oedema
– neovascular glaucoma

Question 9

Multiple sclerosis

Answer 9

Can cause inflammation and damage to the myelin sheath in the optic nerve

Question 10

Hypertension

Answer 10

Can damage the blood vessels that supply the optic nerve

The longer the hypertension has been happening, the more severe the damage is likely to be

Question 11

B12 deficiency

Answer 11

Rarely manifests with visual symptoms

Thought to be via degeneration

Optic neuritis has been reported secondary to vitamin B12 deficiency