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The eyes can be likened to cameras. From shapes, colors, or movements, the eyes capture images of everything they see. After this, the eyes will send all the information they have gathered to the brain for processing to understand what’s happening in the environment.

To capture images, the eyes are composed of various parts. These include the cornea, sclera, iris, pupil, lens, and retina. The cornea acts like a clear glass that serves as a cover and protection for the eyes. The sclera is the white part of the eye. The iris is the colored part of the eyes and controls the amount of light that enters them. Located in the center of the iris is the pupil. Like the iris, the pupil helps control the amount of light that enters the eyes. The pupil visibly contracts in bright conditions and dilates in the dark. As light enters the eyes, the lens focuses this light onto the retina. Once the light is focused, the retina translates it into a type of signal for the brain to start processing it, thus forming images.

However, the eyes can be hampered in performing their function if they sustain damage or encounter problems. As the eyes are made up of various parts, many different types of eye diseases can affect a person. Often, when the eyes develop issues, the patient may experience pain, dryness, itching, or redness of the eyes. In other cases of eye diseases, the patient might experience blurred vision or see unusual shapes, lights, or shadows in their field of view.

It’s possible for a patient to experience the aforementioned symptoms if they lead an unhealthy lifestyle or have other underlying health concerns. Additionally, eye diseases may be passed down by parents to their children or an individual might be born with certain eye conditions.

To treat eye diseases, a patient may need medications, glasses or contact lenses, or even surgery. Depending on the type and severity of the condition, eye diseases could lead to blindness if not promptly addressed.

History of Eye Diseases

The field of medicine dedicated to the study and treatment of the eyes is called ophthalmology. Since ancient times, many doctors, scientists, and researchers have studied and discovered various types of eye diseases. Among them was Sushruta, an Indian surgeon. Around 800 BC, Sushruta identified and described nearly 76 types of eye diseases. Due to his rigorous studies and research, he also successfully performed a surgery on a patient with cataracts and he was thus recognized as the first cataract surgeon.

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Another notable figure who conducted studies on the eyes was Aristotle. Although he was a philosopher and not a doctor, Aristotle is also recognized for his contributions to the advancement of medical knowledge, such as his studies on the structure of the eyes. By dissecting and examining animal eyes, Aristotle discovered that the eyes have three layers or parts. Today, these are known as the fibrous tunic (outer layer), vascular tunic (middle layer), and nervous tunic (inner layer).

During the Middle Ages, the human eyes were studied in more detail using hand lenses and microscopes. Some of the most significant developments during this period were the successful cataract surgeries spearheaded by Georg Joseph Beer and Baron Michael Johann Baptist de Wenzel. Additionally, Ernst Abbe invented various eye equipment, while Hermann von Helmholtz developed the ophthalmoscope in 1851. Thanks to these inventions, diagnosing and treating eye diseases became much easier.

Another crucial milestone in history was the opening of the first eye hospital in 1805. This hospital still stands in London and is known as Moorfields Eye Hospital. Moorfields is also recognized as the largest eye hospital in the world.


Like other parts of the body, the eyes can become diseased or experience problems. Depending on which part of the eye is affected, patients may experience various symptoms such as:

  • Sudden eye pain
  • Persistent eye pain
  • Severe eye pain in minimal light
  • Dry eyes
  • Itchy eyes
  • Redness of the eyes
  • Blurred vision
  • Excess tear production
  • Swollen eyes
  • Small lumps growing around the eyes
  • Color changes in the iris
  • Having white spots on the pupil
  • Eyes appearing cross-eyed
  • Seeing dark spots in the center of one’s vision
  • Difficulty seeing up close or from a distance
  • Double vision
  • Cloudy vision
  • Seeing halos or circles of light
  • Inability to close the eyelids
  • Loss of peripheral vision
  • Seeing specks or floaters in one’s vision
  • Difficulty adjusting to darkness
  • Vision obstructed by a shadow- or curtain-like appearance
  • Changes in vision (e.g., straight lines appearing curved)

A patient may or may not experience all of these symptoms. Each type of eye disease has its own characteristics. Sometimes, a patient might already have an eye problem but won’t experience any symptoms.


There are many reasons why a person might develop eye diseases. Some of the most common causes are:

  • Eye infections. The eyes can become infected due to bacteria, viruses, fungi, and parasites. Often, infected eyes become red, itchy, swollen, watery, and painful. Sometimes, infections can also cause blurred vision.
  • Physical injury. Physical damage to the eyes can lead to diseases. Accidents, trauma, and sharp objects can cause injuries, resulting in blurred or lost vision. Even liquids like acids, cleaning agents, and shampoos can harm the eyes. Inhalation of powders, like chalk, can also be risky.
  • Genetic factors or birth defects. Some eye diseases can be inherited from parents, such as cataracts, glaucoma, astigmatism, and myopia. Some babies may also be born with defects in their eyes.
  • Other health conditions. Diseases like diabetes, migraines, high blood pressure, and thyroid disorders may cause eye problems. If the underlying condition isn’t treated, symptoms like eye pain and blurred vision will linger.
  • Allergies. Allergies can also affect the eyes. Due to varied reactions to allergies, some might experience rashes or swelling around their eyes after consuming certain foods.
  • Side effects of medications. There are many medicines that can affect the eyes. If currently taking diuretics, high blood pressure medication, antihistamines, oral contraceptives, or tranquilizers, for example, one might experience dry eyes and other symptoms.
  • Overuse of the eyes. Eyes can get tired, too. Overusing them by reading or using computers or handheld devices for long hours can damage the eyes, eventually leading to blurred vision. Lack of sleep can also affect eye health.

Risk Factors

Both young and old people can develop eye diseases. However, the following factors can increase the likelihood of having them:

  • Aging. As one ages, the eyes might undergo gradual wear and tear from prolonged use or may have been exposed to harmful elements or events over time.
  • Inherited from parents. If one or both parents have eye diseases, their children might also be at risk of having them.
  • Excessive alcohol consumption and smoking. These habits can elevate the risk of eye diseases because alcohol and cigarettes contain toxic substances. They can constrict the blood vessels in the eyes, leading to certain conditions or ailments.
  • Poor nutrition. Vision problems can arise if a person doesn’t maintain a balanced diet. Various nutrients from food assist the eyes in performing their functions effectively.
  • Untreated health conditions. If left untreated, existing health conditions like diabetes, high blood pressure, heart diseases, meningitis, or migraines can result in eye problems. Often, these ailments can cause eye pain and blurred vision.
  • Use of certain medications. Taking some medications like steroids, atropine, trifluridine, and scopolamine can also increase the risk of eye diseases. Therefore, it’s strongly advised to take only the prescribed dosage of these medications.
  • Excessive sunlight exposure. Overexposure to sunlight can also cause eye diseases. It can potentially burn the cornea of the eyes, leading to infections and inflammation.
  • Poor personal hygiene. If a person doesn’t maintain proper hygiene, they might encounter eye problems. This is because microbes on the body can reach the eyes and cause infections.

Treatment and Prevention

Eye diseases are commonly treated with medications, eyeglasses, or surgery. Although most types of eye diseases aren’t life-threatening, one could permanently lose their vision if not addressed promptly.

Treatment for Eye Diseases

Here are some ways to treat eye diseases:

Medications: Depending on the type of eye disease and experienced symptoms, a doctor may prescribe medications. Commonly recommended medicines include:

  1. Eye drops: If the eyes are dry, a doctor may prescribe eye drops. It’s important for the eyes to remain moist to help clear away dust and other debris. Most eye drops are available over the counter. However, specific types require a prescription, especially those for conditions like glaucoma.
  2. Antibiotics: If the eyes are infected by bacteria, doctors might prescribe antibiotics. Conditions like bacterial conjunctivitis or “sore eyes” can be treated with this type of medication. If the infection is viral or fungal, however, antibiotics won’t be effective.
  3. Corticosteroids: Often, eyes become inflamed when infected. To reduce the inflammation, doctors can prescribe corticosteroids, which can provide relief. Eye conditions treated with corticosteroids include uveitis and allergic conjunctivitis.
  4. Antihistamines: Antihistamines are a type of medication that alleviate allergies or itchiness in the body, including the eyes. Patients with allergic conjunctivitis often get prescribed this medication.
  5. Home remedies: Apart from the above-mentioned medications, cold or hot compresses can also be used to relieve simple eye discomfort. These simple home remedies can soothe conditions like black eyes or styes. Additionally, washing eyes with cold water can be helpful.

Eyeglasses and Contact Lenses: Patients may use eyeglasses or contact lenses to correct their vision. Note that the lens’s degree might differ for each eye. Those who dislike wearing glasses can opt for contact lenses, which are tiny plastic discs placed directly on the eyes to improve vision.

Surgery: A patient might require surgery if they have a significant vision problem or are at risk of blindness due to a specific condition. Some types of eye surgeries include:

  1. Refractive Surgery: Also known as vision correction surgery, this is commonly performed when a patient struggles with near or far sightedness. After a successful surgery, a patient might not need glasses or contact lenses anymore. Some types of refractive surgeries include:
    • Corneal refractive surgery: This procedure corrects the curvature or shape of the cornea to focus light accurately onto the retina.
    • LASIK (Laser in situ keratomileusis): A type of refractive surgery that can correct conditions like myopia, hyperopia, and astigmatism. Recovery from LASIK surgery is usually quick.
    • Photorefractive surgery: Similar to LASIK, this procedure corrects myopia, hyperopia, and astigmatism. However, recovery from this procedure is comparatively longer.
  2. Lens Implants: If refractive surgery isn’t suitable, lens implants can be an option for patients. In this procedure, the surgeon removes the eye’s natural lens and replaces it with a new one to correct vision.
  3. Cataract Surgery: Typically performed when a patient with cataracts is at risk of vision loss. In this procedure, the surgeon removes the clouded lens and replaces it with an artificial one to restore clear vision.
  4. Glaucoma Surgery: This surgery is performed to reduce the accumulated pressure in the eyes. Unlike cataract surgery, this procedure can’t restore lost vision.
  5. Eye Surgery: Surgery might be necessary if the eyes are severely damaged due to an accident or trauma. It can also be done to remove any attached or damaging foreign objects from the eyes.

Prevention of Eye Diseases

To prevent the onset of eye diseases, the following precautions are recommended:

  • Eat a balanced and nutritious diet. To ensure that the eyes receive necessary nutrients, one should consume a balanced and nutritious diet. Foods that help maintain clear vision are those rich in vitamin A, vitamin C, lutein, zeaxanthin, antioxidants, and omega 3. Many of these nutrients are typically found in colorful fruits and vegetables, while omega 3 can be found in seafood like salmon and tuna.
  • Quit smoking and reduce excessive alcohol consumption. These vices damage the cells and vessels of the eyes because they contain many harmful substances.
  • Protect your eyes from sunlight. To minimize glare from the sun’s rays, wear shades/sunglasses or a hat. These help shield the eyes from radiation or harmful light coming from the sun.
  • Rest your eyes. Make it a habit to rest your eyes when reading a book or using a computer for long hours. Doing this prevents eye strain and dryness due to excessive use.
  • Exercise regularly. To keep any part of the body active and healthy, daily exercise is essential. Studies show that exercising also helps reduce the possibility of developing age-related eye diseases.

In addition to the steps mentioned above, it’s also advisable to have your eyes checked by a doctor at least once a year to determine if they have any issues, ensuring that appropriate treatment can be applied promptly if necessary.

Types of Diseases

Various types of eye diseases can affect an individual. These include the following:

  • Adie’s pupil
  • Age-related macular degeneration
  • Eye allergies
  • Amblyopia
  • Anisocoria
  • Anterior uveitis
  • Arcus senilis
  • Astigmatism
  • Bacterial keratitis
  • Blocked tear ducts
  • Blepharitis
  • Branch retinal vein occlusion (BRVO)
  • Cellulitis
  • Central retinal vein occlusion
  • Central serous chorioretinopathy
  • Chalazion
  • Charles Bonnet syndrome
  • Choroidal neovascular membranes
  • Chronic angle-closure glaucoma
  • Coloboma
  • Color blindness
  • Computer vision syndrome
  • Contact lens-related eye infections
  • Convergence insufficiency
  • Corneal abrasion
  • Corneal dystrophies
  • Corneal erosion
  • Corneal laceration
  • Corneal ulcer
  • Cytomegalovirus retinitis
  • Diabetic eye disease
  • Diabetic retinopathy
  • Drusen
  • Endophthalmitis
  • Eye coordination disorder
  • Eye lymphoma
  • Eyelid spasm and twitching
  • Farsightedness (Hyperopia)
  • Floaters and flashes
  • Fuch’s dystrophy
  • Fungal keratitis
  • Giant cell arteritis
  • Giant papillary conjunctivitis
  • Glaucoma
  • Graves diseases
  • Hemangioma
  • Herpes keratitis
  • Heterochromia
  • Histoplasmosis
  • Hyphema
  • Idiopathic intracranial hypertension
  • Iridcorneal endothelial syndrome
  • Ischemic optic neuropathy
  • Juvenile idiopathic arthritis uveitis
  • Juvenile macular degeneration
  • Eye cancer
  • Cataract
  • Keratitis
  • Keratoconus
  • Stye (Kuliti in Tagalog)
  • Lazy eye
  • Learning-related vision problems
  • Macular edema
  • Macular hole
  • Macular pucker
  • Macular telangiectasia
  • Blurry or poor vision
  • Marfan syndrome
  • Microvascular cranial nerve palsy
  • Myasthenia gravis
  • Myokymia
  • Myopia (Nearsightedness)
  • Nevus
  • Nystagmus
  • Ocular allergies
  • Ocular hypertension
  • Ocular melanoma
  • Ocular rosacea
  • Onchocerciasis (African river blindness)
  • Optic neuritis
  • Orbital fracture
  • Strabismus or crossed eyes
  • Detached or torn retina
  • Eye strain
  • Black eye
  • Dry eye
  • Photokeratitis
  • Pigment dispersion syndrome
  • Pinguecula and pterygium
  • Posterior vitreous detachment
  • Presbyopia
  • Pseudoexfoliation syndrome
  • Ptosis
  • Retinal artery occlusion
  • Retinal detachment
  • Retinitis pigmentosa
  • Retinoblastoma
  • Retinopathy of prematurity
  • Scleritis
  • Sjogren’s syndrome
  • Sleep crust
  • Sore eyes (Conjunctivitis)
  • Stargardt disease
  • Stickler syndrome
  • Subconjunctival hemorrhage
  • Toxoplasmosis
  • Trachoma
  • Trichiasis
  • Trichotillomania
  • Usher syndrome
  • Uveitis
  • Vitamin A deficiency
  • Vitreomacular traction

The type of eye disease a patient has can be identified with the help of a specialist eye doctor or ophthalmologist. Ophthalmologists typically examine, diagnose, and treat eye diseases. However, if the eye problem is primarily related to incorrect vision grade, one can approach an optometrist. An optometrist is also an eye doctor, but they mainly prescribe the appropriate grade of eyeglasses or contact lenses to correct vision.