Disease Database - Page 59

OphthalmologyOphthalmology

Blindness

Blindness, also known as amaurosis, is defined by the World Health Organization as visual acuity of less than 0.05 in the better eye with best correction, or a central visual field of less than 10 degrees. This means that a blind person, even with corrective lenses, needs to stand 20 feet (6.1 meters) from an object to see what a person with normal vision can see from 400 feet (120 meters). Blindness can be divided into two types based on its cause and time of onset: Congenital blindness: Blindness caused by incomplete optic nerve development or abnormal eyeball development due to pathogenic factors or genetic abnormalities during early embryonic development. Acquired blindness: Blindness that occurs after birth due to diseases, medications, environmental factors, or psychological factors. Causes Blindness can be caused by various factors, primarily related to the following: Disease factors: Ophthalmic diseases: These are the most common causes of blindness. Others: Neurological diseases, systemic diseases, and congenital diseases can also cause blindness. Poisoning: Including chemical and food contamination, such as methanol, ethylene glycol, arsenic, lead, carbon monoxide, and bromide poisoning. Medication factors: Side effects of drugs such as ethambutol, isoniazid, amantadine, chloroquine, chlorpromazine, vincristine, and phenothiazines can cause optic nerve damage, leading to blindness. Trauma factors: Various types of trauma affecting the eyeball, occipital bone fractures, or skull fractures involving the sphenoid bone can affect the optic nerve, leading to acute blindness. Environmental factors: Without eye protection, such as during mountaineering or skiing in high altitudes or snowy areas, electric welding operations, or reading under strong lights, the eyes can be excessively exposed to ultraviolet radiation, leading to acute blindness. Psychological factors: In cases of severe psychological stress or extreme emotional fluctuations, sudden blindness may occur, known as hysterical blindness. In such patients, pupillary light reflex and fundus examination are normal, with no organic lesions. Lifestyle: Can be seen in alcohol and tobacco poisoning, especially with inferior products.

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OphthalmologyOphthalmology

Lacrimal system diseases

The lacrimal system can be structurally and functionally divided into the lacrimal secretion part and the lacrimal drainage part. Lacrimal secretion part: Includes exocrine glands such as the lacrimal gland, accessory lacrimal glands, and conjunctival goblet cells. Lacrimal drainage part (lacrimal passages): Includes the upper and lower puncta, upper and lower canaliculi, common canaliculus, lacrimal sac, and nasolacrimal duct. Its main function is to drain tears into the nasal cavity. Lacrimal system diseases refer to diseases affecting these two parts. They mainly include dacryoadenitis, lacrimal gland tumors, excessive tear secretion, insufficient tear secretion, lacrimal duct obstruction or stenosis, and acute/chronic dacryocystitis. The main symptoms are epiphora (tears overflowing outside the eyelids because they cannot drain into the nasal cavity) or tearing (tears flowing out of the eyelids because the drainage system cannot remove them quickly enough).

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OphthalmologyOphthalmology

Lens dislocation

Normally, the periphery (360 degrees) of the lens is suspended from the ciliary body within the eyeball by the suspensory ligaments. Lens luxation is an abnormal displacement of the lens due to congenital factors, trauma, or suspensory ligament disease. Clinically, two types are observed: complete lens luxation and partial lens luxation (subluxation). The main symptom is a significant decrease in vision, with some patients experiencing monocular diplopia.

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OphthalmologyOphthalmology

Scleritis

The sclera is the tough, white, fibrous outer layer of the eyeball. It is a connective tissue that extends from the edge of the cornea (commonly known as the "black of the eye") to the optic nerve at the back of the eye, giving the eye its white appearance and helping to maintain its shape. Scleritis is a severe, destructive, and vision-threatening inflammatory reaction involving the deep and entire scleral tissue. It is a serious eye disease often associated with underlying autoimmune conditions. Based on the depth of the lesion, it can be divided into two types: Episcleritis: The lesion is relatively superficial, and treatment is comparatively simple. Some patients may even recover spontaneously without special treatment. Scleritis: The lesion is deep and extensive, and it may be a manifestation of a systemic disease in the eye. Treatment is relatively difficult, the treatment cycle is long, and it is particularly prone to recurrence. Episcleritis commonly affects young and middle-aged adults aged 20-50, with a female-to-male incidence ratio of 3:1. Scleritis commonly affects individuals aged 40-60, with a higher incidence in females. The onset of this disease is acute, and the main symptoms are red eyes and eye pain.

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OphthalmologyOphthalmology

Conjunctival diseases

The conjunctiva, with most of its surface exposed to the external environment, is susceptible to irritation from external factors and microbial infections, leading to various diseases. Conjunctival diseases encompass a broad category, with conjunctivitis being the most common, followed by degenerative diseases, and also including rare conjunctival tumors. Conjunctivitis: Common types include viral and bacterial conjunctivitis, allergic conjunctivitis, and conjunctivitis caused by foreign body irritation. Conjunctival degenerative diseases: These include pinguecula, pterygium, and conjunctival concretions. Conjunctival tumors: These include primary benign conjunctival tumors, such as conjunctival nevi and conjunctival papillomas, and primary malignant conjunctival tumors, such as conjunctival intraepithelial neoplasia and conjunctival squamous cell carcinoma.

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OphthalmologyOphthalmology

Orbital disease

Orbital diseases are mainly divided into two categories based on their location: orbital wall lesions and orbital content lesions. The main lesions involved include the following: Neoplastic lesions: Cavernous hemangioma and lymphangioma originating from blood and lymphatic vessels. Neurofibroma and schwannoma originating from peripheral nerves. Optic nerve glioma and meningioma originating from the optic nerve and its sheath. Lacrimal gland pleomorphic adenoma and lacrimal gland carcinoma originating from the lacrimal gland. In addition, there are cysts, sarcomas, lymphomas, and metastatic cancers. Inflammatory lesions: Infectious lesions: orbital cellulitis, abscess. Non-infectious inflammatory lesions: inflammatory pseudotumor, thyroid-associated ophthalmopathy. Congenital anomalies: dermoid cyst or epidermoid cyst, orbital bone developmental malformation, etc. Vascular lesions: vascular malformations, varicose veins, etc. Orbital trauma: orbital wall fracture, intraorbital foreign body, hemorrhage, etc. The main symptoms include proptosis, fundus edema, hemorrhage, and blurred vision.

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OphthalmologyOphthalmology

Uveal disease

The uvea is located between the sclera and the retina of the eyeball, mainly including the iris, ciliary body, and choroid. Because it contains pigment and is colored, resembling a purple grape, it is called the uvea. Uveal diseases are related conditions affecting the uvea, with inflammation being the most common, followed by tumors, and some congenital or degenerative changes. They mainly include the following types of diseases: Uveitis: Clinically, inflammation occurring in the uvea, retina, retinal blood vessels, and vitreous is collectively referred to as uveitis. It primarily affects young and middle-aged adults and is a common and significant cause of blindness. Tumors Benign uveal tumors: Iris cysts, iris nevi, choroidal nevi, and choroidal hemangiomas, etc. Malignant uveal tumors: Malignant melanoma of the iris, malignant melanoma of the choroid, metastatic choroidal carcinoma, etc. Congenital uveal abnormalities Congenital aniridia, iris coloboma, congenital iris cysts. Persistent pupillary membrane, congenital pupillary dyscoria, polycoria. Ciliary body developmental abnormalities. Congenital choroidal coloboma. This disease is more common in young and middle-aged adults, with a higher incidence in males than females. Main symptoms include conjunctival hyperemia, floaters, and blurred vision. Different stages present with different manifestations, which can be localized, disseminated, or diffuse tissue damage.

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OphthalmologyOphthalmology

Optic atrophy

The optic nerve is the pathway connecting the eye and the brain. After receiving light information, the eye transmits signals to the brain via the optic nerve. Optic atrophy refers to a morphological change where the optic nerve completely thins due to lesions in retinal ganglion cells and their axons caused by any disease. It is the final outcome of optic nerve damage. The main symptoms include decreased vision, visual field changes, and color vision impairment.

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OphthalmologyOphthalmology

Diplopia

Diplopia refers to the abnormal phenomenon where a person perceives two images of a single object when looking with both eyes. There are many causes of diplopia. If one or more of the six muscles that control eye movement are inflamed, injured, or suffer from nerve damage, the eye muscles will become uncoordinated, which can lead to diplopia.

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