Ophthalmology is the study of diseases of the eye. 

Ophthalmologists specialize in the medical and surgical treatment of the eye.

A general practitioner may refer someone to an ophthalmologist if they exhibit symptoms of cataracts, eye infections, optic nerve problems, or other eye conditions.


Ophthalmologists are trained to perform a wide range of medical procedures and surgeries. 

There are several factors that determine what procedures an ophthalmologist performs on a regular basis, including their practice type and specialty.

One of the most common everyday procedures an ophthalmologist performs is diagnosing and monitoring mild eye and vision conditions. 

Additionally, they will prescribe and fit glasses and contact lenses to correct vision problems.

Most subspecialist ophthalmologists perform fewer procedures on a daily basis, focusing instead on the treatment of one condition or several related conditions.

Subspecialists commonly perform the following procedures:

  • diagnosis and monitoring of moderate-to-severe eye conditions
  • injections around the eyes and face to alter facial structure function and appearance
  • repairing torn or detached retinas
  • corneal transplants
  • reconstructive surgery to repair trauma or birth abnormalities, such as crossed eyes
  • chronic or severe tear duct infections or blockages
  • neoplasm (tumor, cyst, or foreign object) removal
  • monitoring or consulting on cases relating to other conditions, such as diabetic retinopathy or immune conditions
  • cataract surgery
  • glaucoma surgery
  • refractive surgery to correct vision
  • cancer treatment


We have a natural lens inside our eyes. When light rays enter the eye, the lens bends (refracts) them to help us see. This lens should be clear.

A cataract is a cloudy lens. 

The image resembles a hazy windshield of a car. 

With a cataract, things appear blurry, hazy, or less colorful.

Eye Infections

Bacteria, fungi, and viruses can cause infections in the eyes. 

Different parts of the eye can become infected, and they can affect one or both eyes. 

The most common infections are:

  • Conjunctivitis
    • Also known as pink eye
    • It is usually caused by an infection
    • Kids often get it, and it is highly contagious
  • Stye
    • An eyelid bump caused by bacteria getting into the hair follicle of an eyelash.

Infections of the eye can cause redness, itching, swelling, discharge, pain, or difficulty seeing. 

Depending on the cause, treatment may include compresses, eye drops, creams, or antibiotics.

Optic Nerve Problems

More than 1 million nerve fibers make up the optic nerve, which transmits visual messages. 

There is one connecting the back of each eye (your retina) to your brain. 

Optic nerve damage can result in blindness. 

Where the damage occurs determines the type and severity of vision loss. 

One or both eyes may be affected.

Different types of optic nerve disorders exist, including:

  • Glaucoma
  • Optic Neuritis
  • Optic Nerve Atrophy
  • Optic Nerve Head Drusen

If you are experiencing vision problems, contact your healthcare provider. 

Testing for optic nerve disorders may include an eye exam, an ophthalmoscopy (an examination of the back of the eye), and imaging tests. 

Treatment for optic nerve disorders varies. In some cases, you may recover your vision. 

Others do not respond to treatment, or treatment may only prevent further vision loss.


A group of diseases known as Glaucoma can damage the eye’s optic nerve. 

Glaucoma is one of the leading causes of blindness in the United States. 

Optic nerve damage usually occurs when the fluid pressure inside the eyes gradually increases, causing the optic nerve to be damaged. 

At first, no symptoms are present. 

Glaucoma patients will slowly lose their peripheral vision if they do not receive treatment. 

It is as if they are looking through a tunnel. 

As time passes, straight-ahead vision may diminish until no vision is left.

Glaucoma can be detected during a comprehensive eye exam. People at risk should have their eyes examined at least every two years. Those at risk include:

  • African Americans over age 40
  • People over age 60, especially Mexican Americans
  • People with a family history of glaucoma

Glaucoma cannot be cured, but it can usually be controlled. 

Early treatment can help you avoid losing your sight.

Treatment usually involves prescription eye drops and/or surgery.

Optic Neuritis

Optic Neuritis is swelling in your eye, near the optic nerve.

Swelling (inflammation) damages the optic nerve – a bundle of nerve fibers that transmits visual information from your eye to your brain. 

Optic neuritis symptoms include eye pain when moving the eye and temporary loss of vision in one eye.

Optic neuritis can be the first symptom of multiple sclerosis (MS), or it can develop later on in the course of MS. 

MS is a disease that damages and inflames the nerves in the brain and the optic nerve.

Optic nerve inflammation can also occur with other conditions, such as infections or immune disorders, such as lupus. 

A rare disease called neuromyelitis optica can inflame the optic nerve and spinal cord.

After a single episode of optic neuritis, most people recover their vision without treatment. 

Steroid medications may sometimes speed the recovery of vision after optic neuritis.

Optic Nerve Atrophy

ONA (optic nerve atrophy) is a disease in which the optic nerve is damaged mildly to severely, impacting vision in the central, peripheral, and color ranges. 

In children, ONA may cause nystagmus (rhythmic involuntary eye movements).

Optic Nerve Head Drusen

The optic nerve is the physical link between the eye and the brain. 

Through the optic nerve, visual information received by the eye is transmitted to the brain. 

A drusen is a collection of protein and calcium that accumulates within an optic nerve. 

Drusen usually affects both eyes (bilateral), but can occasionally affect only one eye (unilateral).

Optic nerve drusen are often found by your ophthalmologist as an incidental finding since they are often asymptomatic. 

Typically, they are discovered when you have an eye exam. 

After pharmacologic dilation, your ophthalmologist may observe obvious drusen in your optic nerve. 

An obvious drusen is usually evident on the optic nerve surface. 

There are some optic nerve drusen that are “buried.” Buried drusen are more difficult to examine, and diagnosis may require imaging (ultrasound or CT scan), photography (fluorescein angiography/autofluorescence), or optical coherence tomography (OCT). 

Drusen is an inherited disease, so it may be helpful to examine other family members.

Optic nerve drusen usually does not affect vision, but peripheral vision loss may occur. 

The condition is usually mild and goes unnoticed by the patient. 

Children with decreased peripheral vision may undergo visual field tests to monitor their condition. 

Choroidal neovascular membranes are extremely rare complications of optic nerve drusen. 

They are a collection of abnormal blood vessels growing beneath the retina near the optic nerve. 

Occasionally, these membranes may bleed, resulting in a temporary loss of central or “straight ahead” vision.

The biggest problem with drusen is that they can cause confusion. 

Some patients are referred to an ophthalmologist for “suspicious” optic nerves. 

There is potential for swelling in an optic nerve, which is known as edema. 

High levels of pressure within the brain (known as papilledema) may cause swollen optic nerves.  

Papilledema presents as a medical emergency and may require urgent neuroimaging, lumbar puncture, and hospitalization for diagnosis. 

Due to Drusen, the optic nerve may appear swollen when it is not. 

Because the nerve isn’t truly swollen, it is called PSEUDOpapilledema. 

These two conditions- optic nerve drusen and papilledema- may appear similar, but they are in fact quite different. 

It is very important to distinguish between these two conditions to avoid unnecessary testing. 

Most ophthalmologists are able to distinguish between the two.

Currently, there is no effective treatment for drusen. 

In the rare case of choroidal neovascularization, laser treatment may be indicated to treat bleeding.

Ophthalmology Frequently Asked Questions

Optometrists diagnose and treat patients’ eyes. 

Ophthalmologists treat eye conditions with medical and surgical treatments. 

Education levels also differ between the three types of eye health professionals.

Ophthalmology is the study of diseases of the eye. 

Ophthalmologists specialize in the medical and surgical treatment of the eye.

Ophthalmologists diagnose and treat eye diseases, perform eye surgery, and prescribe and fit eyeglasses and contact lenses to treat vision problems. 

A large number of ophthalmologists are also involved in scientific research related to eye diseases and vision disorders.

Cataracts develop when aging or injury affect the tissue that makes up the eye’s lens. 

As a result, proteins and fibers in the lens begin to break down, causing vision to become hazy or cloudy. 

Cataracts can be caused by inherited genetic disorders that cause other health issues.

Cataracts cannot be cured or removed unless they are surgically removed. 

It is impossible to eliminate existing cataracts with medication, and no eyewear can completely counteract their effects. 

Ophthalmologists are seeking nonsurgical solutions, but there are none available at this time.

As cataracts progress, they begin to interfere with vision. 

A loss of sight can affect many aspects of a person’s life, including reading, working, hobbies, and sports. 

Cataracts will eventually blind a person completely if left untreated.

The most common eye infection is conjunctivitis. 

It is usually caused by a virus and does not require antibiotic eye drops. 

Blindness is a result of infectious keratitis. 

It requires immediate medical attention.

You should clean your eyelids with mild, scent-free soap and water. 

You can take over-the-counter pain relievers, such as acetaminophen (Tylenol), to relieve pain and swelling. 

Until the infection clears, you shouldn’t wear contact lenses or eye makeup. 

To help kill the infectious overgrowth, you can apply antibiotic ointments. 

Consult with your optometrist or ophthalmologist if the condition becomes worse, or if it isn’t getting better with home treatments.

The most common form of glaucoma is open-angle glaucoma, which results in increased eye pressure. 

Glaucoma often has no early symptoms, which is why 50% of people do not know they have it. 

Although there is no cure (yet) for glaucoma, if it is caught early, you can preserve your vision and prevent it from worsening.

When inflamed, optic neuritis can cause temporary vision loss. 

Left untreated, however, optic neuritis can cause permanent vision loss as well.

Symptoms of optic neuritis usually go away on their own without medical treatment. 

However, you should continue to take regular MS medications. 

In some cases, doctors may recommend additional treatments to help speed up recovery.