Iraqi Board Ophthalmology key terms

A single number representing a refractive error, calculated as the spherical power plus half the cylindrical power. It estimates the eye's overall defocus and is used when comparing refractions or judging myopia severity.

Retinoscopy or autorefraction performed after paralysing the ciliary muscle with drugs such as cyclopentolate or atropine. It removes accommodation, revealing the true hyperopic error, and is essential in children and in accommodative esotropia.

A refractive condition in which the eye's optical power differs between meridians, so light from a point does not focus at a single point. Regular forms arise from toroidal corneal or lens curvature; irregular forms follow scarring, keratoconus, or surgery.

A progressive non-inflammatory corneal ectasia with central or paracentral thinning and conical protrusion, producing irregular myopic astigmatism. Signs include Fleischer ring, Vogt striae, and scissoring on retinoscopy; management ranges from spectacles to cross-linking and keratoplasty.

A treatment that stiffens the cornea by applying riboflavin and ultraviolet-A light, halting keratoconus progression. The epithelium is usually removed (epi-off) to allow riboflavin penetration; patients must be warned about post-procedure haze and temporary visual drop.

Measurement of corneal thickness, most often by ultrasound or Scheimpflug imaging. Central thickness guides glaucoma risk assessment, contact lens fitting, and eligibility for refractive surgery or cross-linking; thin corneas are a risk factor for keratoconus and pressure-related damage.

The reference method for measuring intraocular pressure, using a prism that flattens a fixed corneal area under slit-lamp illumination. Readings depend on corneal thickness and curvature, so results must be interpreted alongside pachymetry and optic disc findings.

A chronic progressive optic neuropathy with characteristic disc cupping and field loss, in which the anterior chamber angle is open. Raised intraocular pressure is the main modifiable risk factor, but a substantial proportion of patients present with pressure in the statistically normal range.

Examination of the anterior chamber angle using a mirror or prism contact lens, allowing direct visualisation of structures such as the trabecular meshwork and detection of closure, synechiae, or neovascularisation. It is essential for classifying glaucoma before treatment.

A condition in which the iris obstructs the trabecular meshwork, usually in eyes with a shallow anterior chamber and short axial length. It may be asymptomatic, chronic, or present as acute angle-closure glaucoma with pain, haloes, and a fixed mid-dilated pupil.

A laser procedure creating a small hole in the peripheral iris to equalise pressure between the anterior and posterior chambers. It is used to relieve pupillary block in angle closure and as prophylaxis in susceptible fellow eyes.

A reproducible area of reduced retinal sensitivity on perimetry, described by its pattern and location. Glaucomatous defects respect the horizontal midline and include nasal steps, arcuate scotomata, and paracentral loss; neurological defects respect the vertical midline.

Loss of the temporal half of vision in both eyes, caused by a lesion compressing the optic chiasm, most often a pituitary adenoma. Because crossing nasal fibres are damaged, patients may report bumping into objects and have reduced colour vision centrally.

A diminished pupillary constriction when light is swung from the healthy eye to an eye with asymmetric optic nerve or extensive retinal disease. It indicates afferent conduction loss and is absent in purely media-related visual loss such as cataract.

Inflammation of the optic nerve, typically presenting with subacute unilateral visual loss, pain on eye movement, colour desaturation, and a relative afferent pupillary defect. It is strongly associated with multiple sclerosis and often improves spontaneously over weeks.

Cataract surgery in which the lens nucleus is fragmented by ultrasonic energy through a small incision and aspirated, leaving the capsule for intraocular lens implantation. It offers rapid visual recovery and is the dominant technique worldwide.

Late clouding of the residual lens capsule after cataract surgery due to proliferation of lens epithelial cells. It causes gradual visual decline months to years later and is treated by neodymium:YAG laser capsulotomy.

Severe inflammation of intraocular fluids and tissues, usually infective, presenting after surgery or trauma with pain, marked visual loss, hypopyon, and vitritis. It is an emergency requiring urgent vitreous sampling and intravitreal antibiotics.

A layer of white blood cells settling in the anterior chamber, visible as a fluid level inferiorly. It signals severe intraocular inflammation, whether infective, autoimmune, or malignant, and always warrants urgent evaluation.

Inflammation of the uveal tract, classified by anatomy as anterior, intermediate, posterior, or panuveitis. Causes include autoimmune disease, infection, and masquerade syndromes; workup is guided by history, laterality, and associated systemic features.

An adhesion of the iris to adjacent structures: posterior synechiae bind iris to lens, anterior synechiae bind iris to cornea. They may cause pupillary block, angle closure, or irregular pupil and are a common complication of uveitis.

Microvascular retinal disease from chronic hyperglycaemia, graded as non-proliferative or proliferative. Features include microaneurysms, haemorrhages, exudates, macular oedema, and neovascularisation; screening and glycaemic control reduce sight loss.

Fluid accumulation within the macula causing thickening and central visual distortion or blur. It occurs in diabetic retinopathy, vein occlusion, uveitis, and after surgery, and is detected clinically or by optical coherence tomography.

Laser treatment applied to peripheral retina in proliferative diabetic retinopathy and other ischaemic retinopathies. By ablating ischaemic tissue it reduces vascular endothelial growth factor drive, causing neovascular regression, at the cost of some peripheral field and night vision.

Separation of neurosensory retina from retinal pigment epithelium caused by a full-thickness break allowing fluid to enter the subretinal space. Risk factors include high myopia, aphakia, trauma, and lattice degeneration; it requires urgent surgical repair.

A non-invasive imaging technique using low-coherence light to produce cross-sectional retinal and anterior segment images at near-histological resolution. It quantifies macular oedema, detects subretinal fluid, and guides anti-VEGF treatment decisions.

Intravitreal injection of agents that block vascular endothelial growth factor, reducing neovascularisation and vascular permeability. It is first-line for diabetic macular oedema, neovascular age-related macular degeneration, and retinal vein occlusion, requiring repeated injections and monitoring.

Reduced best-corrected visual acuity in one or both eyes caused by abnormal visual experience during the critical period, with no organic lesion. Causes include strabismus, anisometropia, and deprivation; treatment is by correcting refractive error, occlusion, or atropine penalisation.

A significant difference in refractive error between the two eyes. It can cause aniseikonia and, in children, amblyopia because the more ametropic eye receives a chronically defocused image.

An inward deviation occurring when a hyperopic child accommodates to clear a blurred retinal image, driving convergence. It typically presents around age two to three years and is managed with full hyperopic correction, sometimes plus bifocals or surgery.

A white pupillary reflex in a child, which is never normal. Differential diagnosis includes retinoblastoma, congenital cataract, retinopathy of prematurity, Coats disease, and persistent fetal vasculature; urgent specialist assessment is mandatory.

The most common primary intraocular malignancy of childhood, arising from retinal precursor cells, often presenting with leukocoria or strabismus. It may be heritable with RB1 germline mutation, bilateral, and associated with second tumours; treatment includes chemotherapy, focal therapy, and enucleation.

Surgical removal of the entire globe with preservation of orbital tissues and extraocular muscles, usually for intraocular malignancy or a blind painful eye. An orbital implant restores volume and a prosthesis provides cosmesis.

Infection of the lacrimal sac, usually secondary to nasolacrimal duct obstruction, presenting with painful swelling below the medial canthus, epiphora, and sometimes discharge. Acute cases are treated with antibiotics and drainage; definitive treatment is dacryocystorhinostomy.

Excessive watering of the eye due to overproduction of tears or, more commonly, impaired drainage through the lacrimal system. Assessment includes syringing and probing to localise obstruction, which may be punctal, canalicular, saccal, or ductal.

A sight-threatening rise in orbital pressure, often after trauma or surgery, that compromises retinal and optic nerve perfusion. Signs include proptosis, pain, ophthalmoplegia, and falling acuity; it demands immediate lateral canthotomy and cantholysis.

Corneal and conjunctival damage from caustic or acidic substances, with alkalis penetrating more deeply and causing greater injury. Management is immediate copious irrigation, removal of particulate matter, and assessment of limbal ischaemia and anterior segment damage.

Adhesion between the bulbar and palpebral conjunctiva, occurring after severe inflammation, burns, or cicatrising disease. It restricts eye movement, causes fornix shortening, and may require mucous membrane grafting with symblepharon ring placement.

A fibrovascular growth of conjunctiva extending onto the cornea, typically from the nasal side in sun-exposed individuals. It may induce astigmatism or obscure the visual axis and is treated by excision with conjunctival autograft to reduce recurrence.

A patient's voluntary agreement to a procedure after receiving understandable information about its nature, purpose, risks, benefits, and alternatives, including the option of no treatment. It must be documented and obtained without coercion, using an interpreter when needed.