What is dry eye syndrome?
Dry eye syndrome, also known as keratoconjunctivitis sicca, is a common ocular condition defined by insufficient tear production or excessive tear evaporation, resulting in a lack of lubrication and moisture on the eye's surface. This...
What is dominant optic atrophy?
Dominant optic atrophy (DOA), also known as Kjer's optic neuropathy, is a hereditary eye disorder characterized by progressive degeneration of the optic nerves, which transmit visual information from the eyes to the brain. This condition...
Definition of Divergence Insufficiency
Divergence insufficiency is a type of strabismus defined by the eyes' inability to diverge properly when looking at distant objects. This condition causes the eyes to turn inward more than usual (esotropia), resulting in symptoms like...
What is Divergence Excess?
Divergence excess is a type of exotropia, or strabismus, in which one eye is misaligned and turns outward. When looking at distant objects, this subtype's eyes deviate more than when focusing on near objects. The condition...
What is Optic Nerve Glioma?
Optic nerve glioma, also known as optic pathway glioma, is a rare, slow-growing brain tumor that develops from glial cells in the optic nerve. These tumors primarily affect children, with the majority of cases diagnosed...
What is Optic Disc Pallor?
Optic disc pallor is a clinical sign that indicates a pale appearance of the optic disc, which is where the optic nerve enters the retina. This pallor is frequently indicative of underlying optic nerve damage...
What is Optic Disc Drusen?
Optic disc drusen are abnormal calcified deposits that form within the optic nerve head. These deposits can cause a variety of visual problems and are frequently discovered incidentally during routine eye exams. Optic disc drusen...
What is Optical Disc Coloboma?
Optic disc coloboma is a congenital eye condition defined by an abnormality or defect in the optic disc, which is where the optic nerve enters the retina. This defect results from incomplete closure of the...
What is Optical Atrophy?
Optic atrophy is a condition characterized by degeneration or damage to the optic nerve, which transmits visual information from the eye to the brain. This degeneration causes a partial or complete loss of vision, depending on...
What is distichiasis?
Distichiasis is an ocular condition characterized by abnormal eyelash growth from the meibomian glands along the eyelid margin, resulting in a double row of lashes. These extra lashes, which can emerge from both the upper and lower...
What is Diabetic Vitreopathy?
Diabetic vitreopathy is an ocular condition that affects the vitreous humor, a clear gel-like substance that fills the gap between the lens and the retina in the eye. This condition is frequently associated with diabetes mellitus...
What is diabetic retinopathy?
Diabetic retinopathy is a serious eye condition that affects people with diabetes mellitus and can lead to vision loss and blindness if not treated. It is the result of blood vessel damage in the retina, the...
What is Diabetic Papillopathy?
Diabetic papillopathy is a rare eye condition that affects people with diabetes mellitus. The swelling of the optic disc, also known as the papilla, where the optic nerve enters the retina, is the defining feature. This...
What is diabetic cataract?
Diabetic cataract refers to a type of cataract that develops in people who have diabetes. Cataracts are defined by the clouding of the eye's natural lens, which is located behind the iris and pupil. Clouding occurs...
What is ophthalmia neonatorum?
Ophthalmia neonatorum is a type of conjunctivitis that typically affects newborns within the first month of life. This condition is distinguished by eye redness, swelling, and discharge and is primarily caused by bacterial or viral infections...
What is onchocerciasis?
The filarial worm Onchocerca volvulus causes Onchocerciasis, also known as River Blindness. It spreads to humans via the bites of infected blackflies (Simulium species), which breed near fast-flowing rivers and streams, hence the name. The disease primarily...
What is an Oculomotor Nerve Palsy?
Oculomotor Nerve Palsy, also known as Third Nerve Palsy, is a neurological condition characterized by dysfunction of the third cranial nerve, which controls the majority of eye movements. This nerve controls the majority of...
What is ocular toxoplasmosis?
The protozoan parasite Toxoplasma gondii causes ocular toxoplasmosis, an eye infection. This condition usually manifests as necrotizing retinochoroiditis, which affects the retina and choroid and can result in severe visual impairment if not treated properly. It...
What is Ocular Surface Squamous Neoplasia?
Ocular Surface Squamous Neoplasia (OSSN) is a type of eye tumor that develops from the squamous epithelium of the conjunctiva and cornea. The neoplasms range from benign dysplasia to invasive squamous cell carcinoma. OSSN...
Definition of Orbital Dermoid Cyst
A dermoid cyst of the orbit is a congenital tumor that forms when ectodermal and mesodermal cells become trapped during embryonic development. These cysts are most commonly found near the lateral aspect of the brow...
What is dermatochalasis?
Dermatochalasis is a condition that causes excess skin on the upper or lower eyelids, as well as weakening of the eyelid connective tissue. This condition is most commonly seen in older adults as a result of the...
What is Dacryoadenitis?
Dacryoadenitis is an inflammation of the lacrimal gland, which produces tears and is located in the upper outer part of each eye. This condition may be acute or chronic. Acute dacryoadenitis is defined by the sudden onset...
What is cystoid macular edema (CME)?
Cystoid macular edema (CME) is a condition in which fluid accumulates in the macula, the central part of the retina responsible for detail vision. This fluid accumulates in cyst-like spaces within the retinal layers,...
What is Cyclic esotropia?
Cyclic esotropia is a rare and distinct type of strabismus defined by a regular and predictable alternation between periods of normal ocular alignment (orthophoria) and periods of inward eye deviation (esotropia). This cyclical pattern typically occurs...
What is orbital lymphoma?
Orbital lymphoma is a cancer that develops in the lymphatic tissues of the orbit, the bony cavity that holds the eye. It is a subtype of non-Hodgkin lymphoma and is a rare but significant cause of...
What is Orbital Hemorrhage?
Orbital hemorrhage is a medical condition characterized by bleeding inside the orbit, the bony cavity that houses the eye. This condition can result from trauma, surgical complications, vascular malformations, or systemic diseases. Orbital hemorrhage can cause...
What are orbital fractures?
Orbital fractures are breaks or cracks in the bones surrounding the eye, known as the orbit. These fractures are most commonly caused by facial trauma, such as accidents, falls, sports injuries, or physical assaults. Orbital fractures...
What is cortical cataract?
A cortical cataract affects the lens of the eye, specifically the outer edge known as the cortex. Cataracts are defined as the clouding of the eye's natural lens, which causes vision impairment. Cortical cataracts begin as...
What exactly is a corneal ulcer?
A corneal ulcer is an open sore on the cornea, the transparent, dome-shaped surface that covers the front of the eye. This condition is frequently caused by an infection, but non-infectious causes such as...
What is Corneal Neovascularization (CN)?
Corneal neovascularization is the formation of new blood vessels in the cornea, the transparent, dome-shaped surface that covers the front of the eyeball. The cornea is normally avascular, which means it lacks blood vessels, in...
