Optic Nerve

The optic nerve is like a telephone cable that connects the eye and the brain.  Light is focused in the through the clear cornea and lens onto the retina.  This amazing living tissue changes the light energy into chemical and electrical signals that pass along the optic nerve to the brain.  Any disease that causes damage to the optic nerve leads to loss of vision and complete blindness in some cases.

Hundreds of different conditions can cause damage to the optic nerve.

They are broken down into several basic categories.

  • Blood flow related (Ischemic Optic Neuropathy)
  • Inflammatory (Optic Neuritis)
  • Infectious (Syphillis, Tuberculosis)
  • Infiltration (Cancer cells)

As an “optic nerve” specialist in Las Vegas Dr. DeBry has examined, tested, and photographed over 50,000 optic nerves in his 12 years of practice.  Our clinic has the best equipment available to assess a patient for optic nerve disorders.  Please contact our office if you would like to schedule an optic nerve evaluation.  Feel free to browse the other optic nerve-related topics on these web pages.

Diplopia (Double Vision):

Misalignment of the eyes resulting in seeing two images of an object in space. Closing one eye alleviates the double. Caused by a problem with one or more muscles of the eye. Not to be confused with monocular (one eye) double vision, which persists even when closing one eye. Usually due to a cataract or dry eye condition.

Sixth Nerve Palsy:

The problem with the muscle responsible for moving the eye out to the ear.

Causes double vision straight ahead, worse when trying to look to the side.  Common in the elderly who have high blood pressure and diabetes and in younger patients with neurologic diseases such as multiple sclerosis.  Usually, resolves without treatment in 6-8 weeks.

Droopy Lid (“PTOSIS”):

Droopy lids are common with age, the muscle responsible for lifting the lid gets weaker with age or if it occurs suddenly or intermittently may be a manifestation of neurologic disease such as myasthenia gravis.

Proptosis (Exophthalmos):

“bulging or protruding eyes or eye” is a manifestation of crowding in the orbit where the eye and the extraocular structures are contained. It may be a manifestation of large muscles and fat that are seen in Thyroid eye disease (TED) or a more serious manifestation of orbital disease from cancer or inflammatory disease.

Thyroid Eye Disease (TED):

Related to but not caused by an autoimmune Thyroid disease called Graves disease.  Patients with TED present with bulging of the eye, double vision, droopy lids, and dry eyes. It usually affects the eyes asymmetrically so one may notice one eye looks bigger than the other.

Anisocoria (Physiologic):

20 percent of the population have unequal pupils. It is of no neurological consequence. It is referred to as Physiologic anisocoria.

Anisocoria (NON-Physiologic):

Non-physiologic “unequal pupils” may be due to trauma, eye surgery, eye drops, systemic medications you are taking, or more serious causes such as a tumor or aneurysm. Also, the larger pupil is not always the “problem” pupil.

Intermittent Aniscoria:

It is common to have intermittent unequal pupils such as during a headache or during stressful times. Pupils that return to normal are not an emergency.

Third Nerve Palsy:

The third nerve of the brain is responsible for pupillary function, moving the lid up and moving the up, down, and towards our nose. A third nerve palsy presents with a droopy lid, inability to move the eye and sometimes pain.  It is associated with high blood pressure, diabetes, and Herpes Zoster. Usually self-limited and improves over time without treatment. If the pupil is involved, it is more ominous and may herald a tumor or aneurysm without pain.

Fourth Nerve Palsy:

The fourth nerve of the brain is responsible for moving the eye down and in. When it doesn’t work you may see double, one image on top of the other.  The most common causes are trauma, high blood pressure, or congenital but neurologic disease such as multiple sclerosis can present with this.

Headache:

Headache is usually not a sign of severe neurologic disease. If it is unremitting, progressive and associated with other neurologic signs such as weakness, numbness, difficulty walking or talking this could be a sign of a stroke, tumor, or of increased intracranial pressure.

Increased Intracranial Pressure:

The skull and spinal cord are filled with cerebrospinal fluid (CSF) that cushions the brain in a bath of fluid. Anything that prevents the normal circulation and drainage of the CSF can result in an increase in the pressure around the brain.  The signs of increased pressure can be a headache, loss of vision, double vision, nausea and vomiting, and seizures.  The causes can be mechanical from tumors or Pseudotumor Cerebri (IIH)

Psudotumer Cerebri:

Also known as idiopathic intracranial hypertension (IIH).  A problem with the brains ability to maintain a normal intracranial pressure resulting in the signs of increased intracranial pressure. Mostly seen in females suggesting a role of estrogen but males are also involved as are individuals taken dermatologic medicines such a acutane, retin A, and tetracyclines.  Treatments are designed to lower the pressure in the cerebrospinal fluid.  This usually requires oral medications such as acetazolamide.

 

Papilledema:

Papilledema is a manifestation of increased intracranial pressure. The optic nerves become swollen due to the elevation of intracranial pressure. Diagnosed by a dilated eye examination and visual field and ocular coherence tomography (OCT).  Moderate-to-severe cases are easily detected.  Mild papilledema may be more difficult to detect due to a wide range of variability in the appearance of the optic nerve.

Optic Neuritis:

An auto-immune inflammation of the optic nerves in one or both eyes resulting in loss of central and/or peripheral vision, loss of red discrimination and loss of brightness. The optic nerves may be swollen or not.   Usually associated with neurologic diseases such as multiple sclerosis, but may be caused by other factors.

Anterior Ischemic Optic Neuropathy (AION):

A condition caused by reduced blood flow to the optic nerve.  There are two variants, both of which present with loss of central and or peripheral vision in one or both eyes.  The optic nerves are swollen.

Anterior Ischemic Optic Neuropathy (ARTERITIC):

Variant 1, in which the patient presents with headache, fatigue, weight loss, pain on chewing and scalp tenderness.  Diagnosed by elevated lab parameters;  ESR, CRP, IL6. A biopsy of the superficial temporal artery is performed to confirm the diagnosis. This is a true neuro-ophthalmologic emergency with serious risks both visually and systemically as the major arteries of the body may be affected. Emergent treatment with oral or intravenous steroids is initiated and usually maintained for over one year.

Anterior Ischemic Optic Neuropathy (NON-ARTERITIC):

Variant 2, the most common.   Presents with painless loss of vision in individuals over the age of 50.  Prognosis for recovery is poor.  It is usually in only one eye, but both eyes may become involved in some cases. THERE IS NO TREATMENT.

Risk factors include high blood pressure and diabetes.  An anatomically small optic nerve is also a risk factor.