Introduction to Dry Eye Syndrome
Dry Eye Syndrome, also known as keratoconjunctivitis sicca, is a common condition in which your tears are unable to adequately lubricate your eyes. Tears can be ineffective and unstable for a variety of reasons. For...
Introduction to Dominant Optic Atrophy
Dominant Optic Atrophy (DOA) is a hereditary eye condition characterized by progressive degeneration of the optic nerves, which causes visual impairment. DOA typically manifests in the first decade of life and primarily affects the transmission...
Introduction to Eales Disease
Eales disease is a rare idiopathic occlusive vasculopathy that primarily affects the peripheral retina and is most frequently seen in young adults. Eales disease, named after British ophthalmologist Henry Eales, who first described it in 1880,...
What is Divergence Excess?
Divergence Excess is a type of strabismus distinguished by a greater degree of exotropia (outward deviation of the eye) when viewing distant objects versus nearby ones. It usually appears in childhood and can last into adulthood...
What is Distichiasis?
Distichiasis is an ocular condition marked by the abnormal growth of an extra row of eyelashes from the meibomian glands, which are located along the eyelid edges. These extra lashes can cause significant discomfort and irritation when...
Introduction to Dissociated Vertical Deviation (DVD)
Dissociated Vertical Deviation (DVD) is a complex ocular condition that frequently affects strabismus patients, particularly those with infantile esotropia. DVD is distinguished by the upward drift of one eye while the other remains focused...
Introduction to Diabetic Vitreopathy
Diabetic vitreopathy is a relatively unknown but significant ocular complication of diabetes mellitus. It entails changes in the vitreous humor, a clear gel-like substance that fills the space between the lens and the retina in the...
What is Diabetic Retinopathy?
Diabetic retinopathy is a serious eye condition that affects people with diabetes. It is distinguished by damage to the blood vessels in the retina, the light-sensitive tissue at the back of the eye, which can cause...
What is Diabetic Papillopathy?
Diabetic papillopathy is a rare but significant ocular complication of diabetes mellitus. It primarily affects the optic disc, resulting in swelling and visual disturbances. Diabetic papillopathy, while often self-limiting, can be an early warning sign of...
Introduction to Diabetic Cataracts
Diabetic cataract is a serious complication of diabetes mellitus that causes a clouding of the eye's lens, resulting in decreased vision and, if left untreated, blindness. This condition is the direct result of diabetes-related metabolic disturbances,...
What is Dermoid Cyst of the Orbit?
A dermoid cyst of the orbit is a benign, congenital lesion caused by ectodermal tissue trapped during embryonic development. These cysts are frequently found in the periorbital region, particularly near the lateral aspect...
What is Dermatochalasis?
Dermatochalasis, also known as "baggy eyes," is a condition that causes excessive sagging or drooping of the upper or lower eyelids due to a loss of skin elasticity. This condition is most commonly associated with aging, but...
What is Dacryocystitis?
Dacryocystitis is an infection or inflammation of the lacrimal sac, a component of the eye's tear drainage system. This condition is frequently caused by an obstruction in the nasolacrimal duct, resulting in the accumulation of tears and...
What is Dacryocele?
Dacryocele, also known as lacrimal sac cyst, is a rare congenital or acquired condition in which the nasolacrimal duct becomes obstructed and distended, resulting in the formation of a cystic swelling at the eye's medial canthus. This...
Introduction to Dacryoadenitis
Dacryoadenitis is an inflammation of the lacrimal gland, which produces tears. This condition, which can be acute or chronic, is distinguished by swelling, pain, redness, and, in some cases, fever in the upper eyelid region containing the...
Introduction
Cytomegalovirus (CMV) retinitis is a serious viral infection of the retina that primarily affects people with weakened immune systems, such as those with HIV/AIDS, organ transplant recipients, or patients receiving immunosuppressive therapy. The condition is caused by the cytomegalovirus,...
What is Cystoid Macular Edema?
Cystoid macular edema (CME) is a condition in which fluid accumulates in the macula, the central part of the retina responsible for detailed vision. This fluid accumulates in cyst-like spaces, causing swelling and distortion of...
What is Cyclic Esotropia?
Cyclic esotropia is a rare type of strabismus marked by intermittent inward deviation of one or both eyes. Unlike typical esotropia, which occurs consistently, cyclic esotropia has a distinct pattern, alternating between periods of normal binocular...
Introduction
Cranial Nerve VI Palsy, also known as abducens nerve palsy, is a neurological condition caused by dysfunction of the sixth cranial nerve. This nerve controls the lateral rectus muscle, which moves the eye outwards. When the sixth cranial nerve...
Introduction
Cranial Nerve IV Palsy, also known as trochlear nerve palsy, is a neurological disorder that affects the fourth cranial nerve, which controls the superior oblique muscle of the eye. This muscle is essential for eye movement, particularly downward and...
Introduction
Cranial Nerve III Palsy, also known as oculomotor nerve palsy, is a neurological condition affecting the third cranial nerve, which controls the majority of the eye's movements, eyelid lifting, and pupil constrictions. Damage or dysfunction in this nerve can...
Introduction to Cortical Visual Impairment
Cortical Visual Impairment (CVI) is a type of vision impairment caused by damage to the brain's visual processing areas rather than problems with the eyes. This condition is frequently seen in children, especially those who...
What is Cortical Cataract?
A cortical cataract is a type of cataract that affects the lens of the eye, causing vision impairment. This condition is distinguished by the appearance of opaque, white opacities or cloudy areas in the lens cortex,...
Overview of Corneal Ulcers
A corneal ulcer is a painful, open sore on the cornea, the transparent, dome-shaped surface that covers the front of the eye. This is a serious ocular emergency that, if not treated promptly, can cause significant...
What is Corneal Neovascularization?
Corneal neovascularization is a pathological condition characterized by the formation of new blood vessels within the normally avascular cornea. This condition can be caused by a variety of factors, including chronic inflammation, infection, hypoxia (low oxygen...
Introduction to Corneal Mucous Plaques
Corneal mucous plaques are a rare but significant ocular condition in which mucoid material accumulates on the corneal surface. These plaques are made up of mucus, inflammatory cells, and other debris that adhere to the...
Introduction to Corneal Laceration
A corneal laceration is a serious ocular injury caused by a cut or tear in the cornea, the clear, dome-shaped surface that protects the front of the eye. This condition can result from trauma caused by...
Introduction to Corneal Graft Rejection
Corneal graft rejection is a serious complication that can develop following a corneal transplant, also known as keratoplasty. This condition occurs when the recipient's immune system recognizes the transplanted corneal tissue as foreign and launches...
Introduction to Corneal Foreign Bodies
A corneal foreign body is any object or material that becomes lodged in the cornea, the clear front part of the eye. This condition is common, particularly in environments with a high concentration of airborne...
What is Corneal Edema?
Corneal edema is characterized by swelling of the cornea, which is the clear, dome-shaped surface that covers the front of the eye. This swelling occurs when fluid accumulates in the corneal layers, resulting in a thickened,...
