What is coloboma?
Coloboma is a congenital ocular condition characterized by tissue loss in one or more eye structures, including the iris, retina, choroid, or optic nerve. The term "coloboma" comes from the Greek word for "curtailed" or "mutilated," which...
What is chronic progressive external ophthalmoplegia?
Chronic Progressive External Ophthalmoplegia (CPEO) is a rare mitochondrial disorder that causes progressive weakness of the external eye muscles, resulting in ptosis (drooping eyelids) and ophthalmoplegia. This condition impairs eye movement and has a...
What is ocular hypertension?
Ocular hypertension is defined as elevated intraocular pressure (IOP) in the eye. Ocular hypertension, unlike glaucoma, does not cause optic nerve damage or vision loss. It is, however, regarded as a significant risk factor for glaucoma...
What is ocular histoplasmosis syndrome?
The Histoplasma capsulatum fungus, which typically enters the body through the respiratory system, causes Ocular Histoplasmosis Syndrome (OHS), a severe eye condition. If not treated properly, this syndrome can cause significant vision loss. It primarily...
What is Ocular Circatricial Pemphigoid?
Ocular cicatricial pemphigoid (OCP) is a rare, chronic autoimmune disease that affects the mucous membranes, primarily the conjunctiva of the eyes. This condition causes progressive scarring and fibrosis, which may result in severe vision impairment...
What is Ocular Chemical Burn?
Ocular chemical burns are serious injuries caused by exposing the eyes to acidic or alkaline substances. These burns can cause significant damage to the eye's structures, resulting in pain, vision impairment, and even blindness if...
What is nystagmus?
Nystagmus is an ocular condition in which the eyes move involuntarily and repetitively. These movements can be horizontal, vertical, or rotary, and they can affect either or both eyes. Nystagmus can be congenital, presenting in infancy, or...
What is Chronic Lacrimal Canaliculitis?
Chronic lacrimal canaliculitis is an ongoing inflammation of the lacrimal canaliculi, which are small channels in the eyelids that drain tears from the eye's surface into the lacrimal sac and then into the nasal cavity....
What is Chronic Angle Closure Glaucoma?
Chronic angle-closure glaucoma (CACG) is a type of glaucoma defined by the gradual closure of the eye's anterior chamber angle, where the iris meets the cornea. This closure prevents the drainage of aqueous humor,...
What is choroiditis?
Choroiditis is an inflammatory disease that affects the choroid, the vascular layer of the eye located between the retina and the sclera. The choroid is responsible for supplying oxygen and nutrients to the outer retina, and inflammation...
What is choroideremia?
Choroideremia is a rare, inherited retinal degenerative disorder that mostly affects men. Mutations in the CHM gene, which encodes the Rab escort protein-1, are to blame. This protein is required for the proper function of cells in...
What is choroidal osteoma?
Choroidal osteoma is a rare, benign osseous tumor that develops in the choroid, the vascular layer of the eye that lies between the retina and the sclera. Choroidal osteomas, first described in 1978, are defined by...
What is nutritional optic neuropathy?
Nutritional optic neuropathy is a rare but serious condition caused by a lack of essential nutrients needed to keep the optic nerves healthy. This condition causes degeneration of the optic nerve fibers, which results in...
What is nuclear sclerosis?
Nuclear sclerosis is a common age-related condition that affects the lens of the eye. The lens nucleus, or central part of the lens, gradually hardens and yellows. As people age, the proteins in the lens can...
What is Norrie disease?
Norrie disease is a rare genetic condition that primarily affects the eyes and causes congenital blindness in male infants. Mutations in the NDP gene, which is required for retinal and inner ear development, cause this condition....
What is Normal Tension Glaucoma?
Normal-tension glaucoma (NTG), also known as low-tension or normal-pressure glaucoma, is a type of glaucoma that causes optic nerve damage despite normal intraocular pressure (IOP). Unlike other types of glaucoma, in which high IOP is...
What is Noninfectious Endophthalmitis?
Non-infectious endophthalmitis is an inflammatory condition of the eye that affects intraocular tissues such as the vitreous and aqueous humors. In contrast to infectious endophthalmitis, which is caused by bacterial, fungal, or viral infections, non-infectious endophthalmitis...
What is a Choroidal Nevus?
A choroidal nevus is a benign pigmented lesion in the choroid, the vascular layer of the eye that lies between the retina and the sclera. These lesions resemble moles on the skin and are made...
What is choroidal neovascularization?
Choroidal neovascularization (CNV) is a serious ocular condition in which new, abnormal blood vessels form from the choroid layer beneath the retina. These new blood vessels break through the Bruch's membrane and invade the subretinal space,...
What is Choroidal Metastasis?
Choroidal metastasis is the spread of cancerous cells to the choroid, the vascular layer of the eye that sits between the retina and the sclera. Because the choroid is rich in blood vessels, it is a...
What is a Choroidal Hemangioma?
Choroidal hemangioma is a benign vascular tumor that develops in the choroid, the layer of blood vessels that connects the retina and the sclera in the eye. This condition is usually divided into two types:...
What is chorioretinitis?
Chorioretinitis is an inflammatory condition that affects the choroid and retina of the eye. The choroid is a layer of blood vessels that connects the retina and the sclera, providing oxygen and nutrients to the retina's outer...
What is non-arteritic anterior ischemic optic neuropathy (NAION)?
Non-arteritic anterior ischemic optic neuropathy (NAION) is a condition that causes sudden, painless vision loss in one eye due to a lack of blood flow to the anterior portion of the optic...
What is neuroretinitis?
Neuroretinitis is an inflammatory condition affecting both the optic nerve (neuritis) and the retina. The optic nerve head swells, and a macular star, a pattern of exudates radiating from the central macula, is present. This condition frequently...
What is neuromyelitis optica?
Neuromyelitis Optica (NMO), also known as Devic's Disease, is a rare autoimmune disorder affecting primarily the optic nerves and spinal cord. This condition causes severe inflammation and demyelination, resulting in optic neuritis and transverse myelitis. These...
What is neurofibromatosis?
Neurofibromatosis is a genetic disorder in which tumors form on nerve tissue. These tumors can form anywhere in the nervous system, including the brain, spinal cord, and nerves. There are three types of neurofibromatosis: neurofibromatosis type 1...
What is neurofibroma of the orbit?
Neurofibroma of the orbit is a benign tumor that develops from peripheral nerve sheath cells. It primarily affects the structures of the eye socket, or orbit, which include the muscles, nerves, and connective tissues...
What is Chlamydial conjunctivitis?
The bacterium Chlamydia trachomatis causes chlamydial conjunctivitis, an ocular condition. This condition primarily affects the conjunctiva, a mucous membrane that covers the front of the eye and the inside of the eyelids. Chlamydia trachomatis is an...
What is Chalcosis?
Chalcosis, also known as chalcosis bulbi, is an ocular condition caused by the intraocular deposition of copper particles. This is usually due to the presence of a copper-containing foreign body within the eye. The condition can develop...
What is Chalazion?
A chalazion is a common, painless lump or swelling that appears on the eyelid as a result of a clogged meibomian gland. These glands, located in the tarsal plate of the eyelid, secrete an oily substance that...
