Arab Board Ophthalmology Final Written key terms

Progressive thinning and outward bulging of the cornea that produces irregular myopic astigmatism and loss of best-corrected vision, seen in keratoconus and after refractive surgery in predisposed eyes.

A cornea with abnormal elevation or inferior steepening on corneal tomography but no clinical signs, carrying increased risk of post-refractive ectasia if surgery is performed.

Measurement of corneal thickness, used to assess ectasia risk, guide refractive surgery planning and interpret intraocular pressure readings that are affected by corneal thickness.

Corneal epithelial breakdown and poor healing caused by reduced corneal sensation, typically after herpes infection, surgery or trigeminal nerve damage, which may progress to ulceration and perforation.

Corneal infection by herpes simplex virus producing dendritic or geographic epithelial ulcers, stromal inflammation and scarring, with a lifelong tendency to recur under stress or immunosuppression.

Growth of blood vessels into the normally avascular cornea in response to hypoxia, inflammation or limbal stem cell deficiency, threatening clarity and predisposing to lipid deposition and graft rejection.

Loss or dysfunction of stem cells at the corneoscleral limbus causing conjunctivalization, persistent epithelial defects, vascularization and scarring of the corneal surface.

Full-thickness defect of the cornea allowing aqueous leakage, often with a flat anterior chamber and positive Seidel test, requiring urgent tectonic support or surgical closure.

Instillation of fluorescein to detect a full-thickness corneal or scleral wound: leaking aqueous dilutes the dye and appears as a clear stream within the green fluorescence under cobalt blue light.

A fibrovascular wedge of conjunctiva extending onto the cornea from the nasal limbus, causing astigmatism, ocular surface irritation and visual axis obstruction in advanced cases.

A benign yellowish conjunctival nodule at the limbus, usually nasal, caused by actinic elastotic degeneration; it does not cross onto the cornea and rarely needs surgery.

Chronic inflammation of the eyelid margins involving the meibomian glands or lash follicles, producing crusting, redness, tear film instability and recurrent conjunctival or corneal irritation.

Obstruction or altered secretion of the lid oil glands leading to evaporative dry eye, unstable tear film, lid margin changes and symptoms of burning and fluctuating vision.

Facial skin and ocular surface inflammation with flushing, telangiectasia, lid margin disease and corneal involvement, often aggravated by heat, sun and certain foods.

Measurement of intraocular pressure by flattening a fixed corneal area with a calibrated prism; accuracy depends on corneal thickness, curvature and rigidity.

Occlusion of the trabecular meshwork by iris, causing acute or chronic intraocular pressure rise with risk of glaucomatous optic neuropathy; acute attacks present with pain, halos and a mid-dilated pupil.

Examination of the anterior chamber angle using a mirrored contact lens, essential for classifying open versus closed angles and identifying abnormal vessels, pigment or peripheral anterior synechiae.

Filtration surgery creating a guarded scleral opening under a partial-thickness flap to drain aqueous into the subconjunctival space, lowering intraocular pressure with risks of hypotony and bleb infection.

Secondary glaucoma caused by fibrovascular membranes in the angle, usually from retinal ischaemia such as diabetic retinopathy or retinal vein occlusion, requiring treatment of the underlying ischaemia.

Laser treatment applied to peripheral retina to reduce ischaemic drive and vascular endothelial growth factor production in proliferative diabetic retinopathy and other ischaemic retinopathies.

Advanced diabetic retinal disease with new vessels on the disc or elsewhere, at risk of vitreous haemorrhage, tractional detachment and neovascular glaucoma, treated with laser or anti-VEGF therapy.

Persistent vitreous adherence to the macula causing distortion, macular oedema and reduced vision, sometimes progressing to a full-thickness macular hole.

A full-thickness defect in the foveal retina, usually idiopathic in older patients, producing a central visual scotoma and distortion, treated surgically by vitrectomy with internal limiting membrane peeling.

A fibrocellular layer growing on the inner retinal surface that wrinkles the macula, causing metamorphopsia and reduced acuity, treated by surgical peeling when symptoms are significant.

Inflammation of the iris and ciliary body, presenting with pain, photophobia, cells and flare in the anterior chamber, and risk of synechiae, cataract and glaucoma.

A layer of white blood cells settling in the inferior anterior chamber, indicating severe intraocular inflammation or infection and requiring urgent evaluation.

An acute, recurrent, unilateral anterior uveitis linked to the HLA-B27 antigen and often associated with ankylosing spondylitis or other seronegative spondyloarthropathies.

Bilateral granulomatous panuveitis occurring after penetrating trauma or surgery to one eye, caused by sensitisation to uveal antigens, prevented by timely enucleation of a blind injured eye.

Severe intraocular infection, most often after surgery or penetrating trauma, presenting with pain, hypopyon and rapid vision loss and requiring urgent intravitreal antibiotics.

Surgical creation of a passage between the lacrimal sac and the nasal cavity to bypass nasolacrimal duct obstruction in patients with persistent epiphora.

Blockage of the tear drainage pathway causing watering, discharge and recurrent dacryocystitis; congenital cases often resolve with probing while acquired cases may need surgery.

Excessive tearing resulting from overproduction of tears or, more commonly, inadequate drainage through an obstructed or malpositioned lacrimal system.

Acute rise in orbital pressure from bleeding, oedema or emphysema that compromises optic nerve perfusion, presenting with pain, proptosis and reduced vision and requiring emergent decompression.

Reduced vision in one or both eyes from abnormal visual experience during the critical period, such as strabismus, anisometropia or deprivation, treatable if detected early.

An inward deviation of the eye, which may be congenital, accommodative or acquired, and can cause amblyopia and loss of binocular vision if uncorrected.

A significant difference in refractive error between the two eyes, which can produce unequal retinal images and lead to amblyopia in the more affected eye.

Optic nerve injury after head or orbital trauma causing sudden visual loss with a relative afferent pupillary defect and variable optic disc appearance, often managed with observation or steroids.

A pupil that dilates rather than constricts when light is swung from the normal to the affected eye, indicating asymmetric optic nerve or extensive retinal dysfunction.

Inflammation of the optic nerve causing subacute monocular visual loss, pain on eye movement, colour desaturation and a relative afferent pupillary defect, often associated with demyelinating disease.

A full-thickness wound of the eye wall from trauma, requiring urgent shielding, antibiotics and surgical repair to prevent infection, prolapse and permanent visual loss.

A defect in the conjunctival filtering bleb after glaucoma surgery allowing aqueous to escape, causing hypotony, shallow anterior chamber and risk of infection.