Pathology (Domain II)

Glaucoma

Pressure of fluid inside the eye damages the optic nerve. Intraocular pressure (IOP) rises above average 20 mmHG. Often, patients will be completely unaware of the condition until it is quite advance. As the optic nerve becomes increasingly damaged the peripheral visual field becomes constricted in a tunnel-like fashion. Tested for by dilated eye exam or computer visual field test.

Macular Degeneration

Early in the onset, patient may report a slightly blurry spot in their vision or that straight lines appear wavy. As the condition advances, blurry spot becomes a dark spot. The end stage is a black spot within the line of vision with only peripheral vision left.

• Has 2 stages

  • 1. Dry stage: macula undergoes only structural changes

  • 2. Wet stage: Blood vessels under the macula leak, causing hemorrhages. Large amount of swelling and scar tissue left behind.

Scotoma

Visual field abnormality, or a blind spot. Can happen in one or both eyes. Temporarily or permanently can’t see as well or can’t see at all in a certain location. Can happen with conditions that affect your optic nerve or certain areas in the brain. There are different types of scotoma.

Positive Scotoma

You are able to see visual abnormality or blind spot, like a spot of color.

Negative Scotoma

You don’t know that you have a blind spot

Central Scotoma

Blind spot is in the middle of your vision. Some people see it as a dark spot straight ahead. Other people can kind of see straight ahead but there’s an area where it’s not clear.

Scintillating Scotoma

Often appears to be jagged or wavy. Can go from light to dark and back again. Is a disruption of electrical signals. Often happens if you have a migraine with aura. Often doesn’t last long.

Paracentral Scotoma

Within 10 degrees of fixation. Its a spot slight off to the side of where you’re looking. May have more than one paracentral scotoma.

Junctional Scotoma

Happens because of damage to the place where the optic nerve and the optic chiasm come together.

Signs and Symptoms of Scotoma

1. Spot where your vision is blocked or distubed

2. Having difficulty seeing certain colors

3. Needing bright light to be able to see well

4. Eye floaters and flashed

Cataracts

Natural clouding, browning, or yellowing of the clear lens inside the eye that can make vision hazy. Often causes no pain. Part of the natural aging process and are found in over 75% of people over the age of 70. Symptoms: blurry vision, sensitivity to light, poor night vision, difficulty driving, need for brighter lighting, double vision in one eye, fading or yellowing of colors, frequent prescription changes. Tested for by glare test.

Glare Test

Shining bright light toward your eyes while you read the eye chart. Simulates glare from sunshine or car headlights.

Congenital Cataracts

Cataract present at birth

Traumatic Cataract

Cataract that forms as a result of an eye injury

Diabetic Retinopathy

Eye disease that can develop from any type of diabetes. Occurs when diabetes damage small blood vessels in the retina. Has a nonproliferative stage and severe proliferative stage. Early stages are not typically associated with visual symptoms. You may experience blurred or distorted vision. Proliferative stage symptoms: dark floaters or loss of vision due to vitreous hemorrhage or retinal detachment.

Diabetic Retinopathy: Nonproliferative Stage

Tiny damaged blood vessels break open, creating small spots of blood within the retina. Occasionally, fluid and other materials leak from damaged vessels causing retinal swelling.

Diabetic Retinopathy: Proliferative Stage

Develops as areas of the retina become ischemic, or starved of blood supply and oxygen. Ischemic retinal tissues release “feed me” signals (vascular endothelial growth factor, or VEGF) and new abnormal retinal blood vessels, called neovascularization, grow and bleed. Bleeding into the vitreous (vitreous hemorrhage) may cause sudden loss of vision. Scar tissue that grows with these new blood vessels can pull on and detach the retina, increasing the risk of permanent vision loss.

Diabetic Macular Edema

Swelling in the macula of the retina

Amblyopia

Develops during the first 7-9 years of life. Occurs when eyes can’t work together, resulting in a “lazy eye.” It is a brain processing problem where where images from one eye can’t be cleared even with glasses or contacts. Effect of strabismus, anisometropia, or other binocular vision issues. Interferes with depth perception. Signs: tilting head, covering one eye, squinting, double vision, light sensitivity. Common treatments: prism, eye muscle surgery, vision therapy.

Refractive Amblyopia

One or both eyes needs a very strong glasses prescription but the patient doesn’t wear one. Due to the need for strong prescription the child is not able to see well and the region of the brain responsible for vision does not develop properly.

Deprivation Amblyopia

Occurs when there is something that blocks the vision to an eye. Can be caused by a droopy eyelid, a cloudy cornea, or a cataract. Visual pathway does not develop properly due to a lack of visual input in affected eye.

Aphakia

Missing the lens in your eye

Pseudoaphakia

Having an artificial lens implanted after the natural eye lens has been removed. Usually happens when lenses with cataracts are removed.

Nystagmus

Rapid, uncontrollable eye movements. Eyes may move up and down, side to side, or in a circular motion. Sometimes people are born with it but it can also be developed later in life. Sometimes results from alcohol or drug use.

Strabismus

Condition in which the eyes are not pointed in the same direction. The misalignment may be constant or may come and go. The misalignment may be the same no matter where the eyes are looking or may be better or worse in different directions. Can occur at any age and is often seen in children.

Blepharitis

Inflammation of the eyelid margin, where the eyelashes start. Usually affects both eyes and may be characterized as “anterior blepharitis” or “posterior blepharitis,” although they are often present simultaneously. Symptoms: irritation, burning, and light sensitivity.

Anterior Blepharitis

Hard scales and crusting form at the base of the eyelashes as a reaction to certain bacteria that live there. Long-standing cases may result in eyelash loss, eyelashes that turn in, or scarring at the base of eyelashes.

Posterior Blepharitis

Affects meibomian glands. When these glands become inflamed the oily secretions become thickened and eventually stop flowing completely.

Ocular Rosacea

When rosacea affects the eyes. Causes inflammation of oil glands in the eyelids and can lead to blepharitis, styes, and ocular surface irritation. Surface irritation of the eye can lead to other inflammatory condition such as conjunctivitis, corneal ulcers, episcleritis, and uveitis. Surface irritation can also cause new abnormal blood vessels to grow into the normally clear cornea.

Stye (Hordeolum)

A type of eyelid infection that occurs when one of the oil (meibomian) glands of the eyelid becomes blocked. Bacteria within the blocked gland cause an infection resulting in a swollen, red bump on the eyelid. Can occur on upper, lower, inside, or outside eyelid. Internal styes tend to be more painful.

Chalazia

Caused by a complete blockage of one of the glands of the eyelid. Is an inflammatory reaction. Its less red and painful than a stye. Can follow a stye when the bacteria in the blocked gland are cleared by the body but the gland continues to be clogged. Tend to persist longer than styes.

Dacryocystitis

An infection of the tear drainage system. If there is a blockage in the tear drainage system, tears can’t drain and bacteria can grow within the duct or lacrimal sac causing dacryocystitis. Can be acute with rapid swelling and pain over a few days, or chronic, lasting weeks to months. Blockage may be due to aging, injury, sinus disease, a mass in lacrimal system, or scarring from previous dacryocystitis.

Drooping Eyelids (Ptosis)

Congenital ptosis will usually have an underdeveloped muscle that lifts the upper eyelid, while adult ptosis can have a variety of causes. Most common cause of adult ptosis is age related loosening of the muscle that lifts upper eyelid. Many often develop ptosis after eye surgery. Can block upper and even central vision. If caused by a nerve problem it can indicate a neurologic disease. In infants, can cause amblyopia by blocking vision or cause astigmatism.

Ectropion

Outward turning of the edge of the eyelid away from the eyeball. Usually the lower eyelid affected. Usually occurs because the lower eyelid tissues relax gravity. Other causes: nerve problems, scarring from sun damage, previous eyelid injury, abnormal growths that pull eyelid out of position. Can lead to tearing problems and dryness of the eye surface.

Entropion

Inward turning of the edge of the eyelid toward the eyeball. Usually the lower lid affected. Causes: aging, eyelid muscle spasms, scarring, and birth defects. Most problems from entropion come from eyelashes rubbing against the surface of the eyeball.

Blepharospasm

Muscles in the eyelids and around the eyes twitch uncontrollably. Both eyes typically involved, and the spasms usually begin as mild twitches and can progress to forceful blinking. Older patients and women tend to be more affected. Can limit a person’s ability to read, drive, or perform other daily activities.