Everyone with Neurofibromatosis (NF); NF1, NF2, and Schwannomatosis, should see a Neuro-Ophthalmologist who is familiar with NF yearly for optic neurological issues that can develop.
A Neuro-Ophthalmologist is a physician (Neurologist or Ophthalmologist), specializing in diseases affecting vision that originate from the nervous system. It is not that an Ophthalmologist would not be familiar enough with some of the neurological issues that are a result of NF, but tests that need to be done and reviewed require seeing a Neuro-Ophthalmologist, including but not limited to the review of actual MRI scans.
What to bring for eye exam:
Some eye issues that are regular occurrences for individuals with NF2 are specific to NF2. These issues can be used as a method for simple diagnosis of NF2 when found in children. Some eye issues can include:
It is estimated that twenty percent of vision loss issues due to NF2 occur for undetermined reasons. Some of the issues listed below can result in other issues also listed. Common Ocular Abnormalities that can develop for NF2 include:
While individuals with NF2 can potentially develop Age Related Cataracts like any other person, there is high risk of Juvenile Cataracts. When Age Related Cataracts develop in people in general, it would develop by 65 years of age, but can develop in individuals as young as 40. However, individuals who have NF2 and develop Juvenile Cataracts, it is a Secondary Form of Cataracts that can develop at birth, or would develop well before 65 years.
The formation of NF2 cataracts is typically PSC Cataracts, which can cause complications in surgical treatment. Individuals with NF2 sometimes develop CC Cataracts.
Juvenile Cataracts can result in visual impairments including; blurry vision, poor vision at night, severe reactions to glare, as well as a visibly cloudy or white spot that can be seen cover the eye.
Posterior Subcapsular / Capsular Cataracts (PSC Cataracts) is a form of Cataract that forms behind the Iris and Lenses in the Posterior Chamber.
PSC visual disturbance is seen as a halo effect or glare around lights.
Cortical Cataracts (CC), is also referred to as Peripheral Cortical Lens Opacities or simply Cortical Opacities, is a form of Cataracts that occurs just behind the Cornea inside the Anterior Chamber of the eye.
CC visual disturbance that would result from this include; peripheral (outside) vision issues at the edges of the lens of the eye as well as result in blurred vision, glare, contrast and depth perception issues.
Surgical options are available for both Cataract forms, typically requires artificial lens "intraocular lens" implantation at the time of cataract surgery to replace the damaged natural lens also known as "crystalline lens". Following Cataract surgery glasses will likely be needed, if glasses are already worn prior to surgery, a new eye exam and lenses would be required.
Retinal Detachment is a possible issue. In prevention of complications or proper quick management of issues it is important to make certain the surgeon is trained in and has done PSC Cataracts in the past.
In addition to age, other factors may increase the risk of cataract development. These include: Diabetes, Smoking, Overexposure to sunlight and certain medications, such as Steroids."
Radiation Treatments- Cataracts are common side effects of total body radiation treatments, which are administered for certain cancers.http://umm.edu/health/medical/reports/articles/cataracts
Retinal Detachment also known as Retinal Tear is the result of a weak or thin retina which detaches leaving a break in the retinal thereby allowing fluid to pass under the retina. Following this the retina peels away from the back of the eye. With this issue the retina separates from the underlying tissue resulting in vision loss and blindness.
Retinal Detachment is typically the result of Cataract surgery weeks or months later, but can also be Spontaneous as well.
Warning signs include flashing lights, floaters, or blind spots.
Surgical options are possible to correct this if done within 24 hours after detachment occurs.
There are 12 pairs of nerves in the Central Nerve System, a left and a right nerve for each nerve type. Some control muscles and others control senses. The Visual Processing Center of the brain is the Occipital Lobe with different areas of the lobe affecting different areas in the visual field.
Four Cranial Nerve pairs control the eyes themselves, including; the Optic Nerve, the Oculomotor Nerve, the Trochlear Nerve and the Abducens Nerve.
CNII (Cranial Nerve 2), carries Vision to the brain. This nerve does not contain Schwann cells.
CN3, (Cranial Nerve 3) has two functions it controls:
CN IV (Cranial Nerve 4), controls eyeball movement, rotating, up, down, left and right.
Lateral Rectus Muscle: lateral vision - left to right
Papilledema is swelling of the optic disc that may cause different intervals of lost and regaining vision, which can become permanent if the cause is not treated. It can be seen in an eye exam as pressure behind the eyes in an eye exam and is typically the result of Hydrocephalus (CSF pressure buildup) from tumor masses in the brain and typically would be seen in both eyes, but it is possible for it to occur in only one. Left untreated Papilledema can result in blindness.
Symptoms: This can be found in an eye exam sometimes before vision loss occurs. Other symptoms include headache or unexplained nausea.
Visual disturbances can include blind spot, blurring of vision or vision loss for different periods of time all which can lead to permanent.
Other symptoms of Papilledema would only be seen in an eye exam by a Neuro-Ophthalmologist and would require an MRI to determine the cause. Persistent and extensive optic nerve swelling, or optic disc edema, can lead to loss of these fibers and permanent blindness.
Retinitis Pigmentosa (RP) is a name used for conditions that can cause Retinal Degeneration, vision loss. Pigmentosa is a layer of cells in the back wall of the eye necessary to process light and differentiate color for the Optic Nerve. This can result in Central Vision loss that may eventually result in Peripheral Vision loss. Central Vision is vision in the center view of the eye, Peripheral is outer vision.
Other names for RP include; 1) Hyperpigmentation RPE; 2) Hyperpigmentation of the Retinal Pigment Epithelium, 3) Pigmented Layer of Retina, Pigmentum Nigrum or Intra-retinal Leakage of Fluorescein.
Retinal Pigment Epithelium (RPE), also known as Pigmented Layer of Retina is a layer in the eye that shields the retina from excess incoming light.
A condition called Combined Hamartoma of the Retina and Retinal Pigment Epithelium (CHRRPE or CHRPE), is when glial tissue is found in different parts of the eye. This causes blood vessels issues and pigment epithelium, resulting in profound vision loss.
Combined hamartoma of the retina and the retinal pigment epithelium is a rare benign lesion in the macula, juxtapapillary, or peripheral location that is commonly found in children and that consists of the glial cells, vascular tissue, and sheets of pigment epithelial cells.
Hamartoma is pigmented benign cell tissue, an excess of normal tissue. Hamartoma of the Retina, is also known as Retinal Hamartoma.
Retinal Microaneurysms are small aneurysm in retinal capillaries. This can be seen as small amounts of swelling in the wall of blood vessels within the eye that look like small, round, red spots.
Nystagmus causes Ocular Flutter (random eyes movement away from point of intended focus) and often results in reduced vision. As Nystagmus gets worse or nothing is done to manage it can lead to Oscillopsia. Oscillopsia can be either mild blurring or rapid and periodic jumping of vision. Oscillopsia is a visual disturbance in which objects in the visual field appear to oscillate. The severity of the effect may range from a mild blurring to rapid and periodic jumping. The development of Nystagmus is common for individuals with NF2; it can be the result of the following issues:
Oscillopsia is an incapacitating condition experienced by many patients with neurological disorders.
Diplopia also known as Double Vision is a common issue for people with NF2. Prism glasses might be options to correct these issues if noticed early enough, otherwise Eye surgery might be the only way to correct this. Talk to your doctor.
Binocular is misalignment with 2 eyes: both eyes facing in, booth facing out, one eye facing in, or one facing out, which is seen as Double Vision.
Binocular Diplopia is the result of Strabismus. There are two form of Strabismus; cross-eye and walleye, they are different angles of perception and can be the result of eye muscle coordination or a brain issue.
Muscle coordination could be the result of damage to Cranial Nerves 3, 4, or 6. This is frequently the result of tumor damage, which can be fixed with surgery to remove the tumor and tightening of the weakened muscles.
Amblyopia is a brain issue that results in one lazy eye that has no vision and vision is only perceived in the other eye. Cross-eye and walleye treated early can prevent the development of Amblyopia.
Monocular Diplopia is damage to an eye that results in double vision seen with only the damaged eye. This is the result of damage to the cornea of the eye itself. This results in multiple images, seen.
Voluntary Diplopia is when an individual has normal eye alignment but can switch to Binocular eye alignment or Binocular eye alignment and can switch to normal eye alignment.
Temporary Diplopia might result in Binocular and Monocular vision and can be the result of; head trauma, certain medications, alcohol, or eye strain. If it continues consult with your optometrist.
There are a many issues that can result in Diplopia, some of which include:
Cornea scars and dry cornea can damage the eye and result in double vision. Dry eyes are a common NF2 issue and many individuals need to use a constant amount of eye drops.
Juvenile Cataracts frequently develops at a very early age for individuals with NF2 and would result in distorted vision.
If the muscle in one of the eyes is weaker than the other, the development of double vision would be the result of the eyes not focusing together.
This might develop if the Facial Nerve is damaged as a result of eyelid closure issues.
The third, fourth, and sixth cranial nerves each control different aspects of eye muscle position. Muscle control can be lost could be a result of one of those cranial nerves and result in Diplopia; CN3 the Oculomotor Nerve, CN4 the Trochlear Nerve or CN6 the Abducens Nerve.
Management of Diplopia can be possible with the following options:
Epiretinal Membrane is a buildup of scar tissue that covers the retina.
A gel that naturally forms over the lens and pupil of the eye called the "the vitreous" are a result of an immune system response to protect the retina. Scar like cells make up this gel, are a form of scar tissue that can form over the eye and damage the retina's surface. At it gets thicker if it does not sit as a flat layer it puckers and the film causes blurry distorted vision.
This is typically the result of Posterior Vitreous Detachment (PVD).
Epreretinal Membrane is also called; Macular Pucker, Cellophane Maculopathy, Retina Wrinkle, Surface Wrinkling Retinopathy, Premacular Fibrosis, and Internal Limiting Membrane disease. This can result in Diplopia also known as double vision.
Dry eyes for individuals with NF2 can be the result of different issues, most commonly; poor circulation, onset of development of nerve damage, or medications.
Many of the tumor suppressor including; Bevacizumab (Avastin™), Lapatinib (Tykerb™) and RAD 001 - Everolimus (Afinitor™). These medications can cause dry eye issues and require excessive individuals to drink more water to compensate.
Dry Eye issues a result of Avastin, typically only results for the first 3 months of treatment. When taking other medications dry eye issues stop when medication is discontinued.
If dry eyes are an issue, it could mean that weakening of the facial nerve. The facial nerve effects the muscles that open and close the eye in addition to producing fluid to keep moisture in the eye. Keeping moisture in the eyes is important to prevent other issues like cracked cornea.
Gaze-evoked tinnitus (GET) is a form of Tinnitus sub form of a class of tinnitus called Somatosensory Tinnitus; is affected by horizontal and / or vertical eye movement, not necessarily both. Eye movements affect pitch and tone heard.
The development of GET is one of the results of damage to hearing. GET can occur after removal of Vestibular Schwannoma (VS) also known as Acoustic Neuroma (AN), which damages Cranial Nerve 8, associated with the Hearing and Balance Nerves. This can start after VS damage in one side of the head and seem to be a sound into that ear, when the eyes move. When VS damage occurs in both ears, also known as Bilateral damage; the sound might be in one or both ears, when the eyes move.
It is unknown exactly why this form of Tinnitus occurs, since it does not always occur after removal of VS, but it is believed to be the result of the brains attempts at find sound.
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