Iraqi Board Ophthalmology flashcards
Iraqi Board Ophthalmology · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Snell's law
- n1 sin θ1 = n2 sin θ2 describes refraction at an interface; total internal reflection occurs beyond the critical angle arcsin(n2/n1).
- Knapp's law
- In axial ametropia, a spectacle lens placed at the anterior focal point (about 15.7 mm) keeps retinal image size unchanged compared with the emmetropic eye.
- Vertex distance conversion
- F2 = F1 / (1 − d·F1), where d is the change in vertex distance in metres; clinically significant above about ±4 dioptres.
- Holden–Mertz criteria
- Minimum oxygen transmissibility for contact lenses: Dk/t ≥ 24 for daily wear and ≥ 87 for extended wear to avoid corneal oedema.
- Fleischer ring
- Iron deposition ring at the base of the cone in keratoconus; a classic slit-lamp sign alongside Vogt striae and inferior steepening.
- Khodadoust line
- Endothelial rejection line seen after corneal grafting; indicates immune rejection and requires intensive topical and systemic steroid therapy.
- Shaffer angle grading
- Gonioscopic grading from 0 to 4; grade 0 is closed and grade 4 is wide open, with grades 0–2 indicating risk of angle closure.
- Goldmann applanation tonometry
- Measures IOP by flattening a fixed corneal area of 3.06 mm diameter; underestimates in thin corneas and overestimates in thick corneas.
- Posterior capsule rupture
- Common complication of phacoemulsification; may lead to vitreous loss, dropped nucleus, and increased risk of endophthalmitis and retinal detachment.
- Endophthalmitis after cataract surgery
- Presents 3–7 days postoperatively with pain, hypopyon, and vision loss; treat with intravitreal vancomycin and ceftazidime after vitreous tap.
- Cherry-red spot
- Fundus sign of central retinal artery occlusion; the fovea appears red against a pale, oedematous retina, with sudden painless vision loss.
- Type 1 ROP
- Retinopathy of prematurity requiring treatment: zone I any stage with plus disease, zone I stage 3 without plus, or zone II stage 2–3 with plus disease.
- Sympathetic ophthalmia
- Bilateral granulomatous panuveitis following penetrating trauma to one eye; prevented by early enucleation of a blind injured eye or prompt primary repair.
- Headlight-in-fog lesion
- Classic fundus appearance of ocular toxoplasmosis: a focal white retinochoroiditis adjacent to an old pigmented scar, with overlying vitritis.
- Argyll Robertson pupil
- Small, irregular pupil that reacts to accommodation but not to light; classically associated with neurosyphilis and other midbrain lesions.
- Leber hereditary optic neuropathy
- Bilateral sequential painless vision loss in young males from mitochondrial DNA mutations, most commonly m.11778G>A; no proven effective treatment.
- Orbital compartment syndrome
- Tense proptosis, pain, and afferent pupillary defect after trauma or surgery; treated emergently with lateral canthotomy and cantholysis.
- Dacryocystorhinostomy
- Surgical creation of a fistula between the lacrimal sac and nasal cavity, used for chronic nasolacrimal duct obstruction causing epiphora or dacryocystitis.
- Amblyopia critical period
- Visual development window up to about 8–10 years; occlusion or atropine penalisation is most effective when started early.
- Leukocoria
- White pupillary reflex; differential includes retinoblastoma, congenital cataract, ROP, Coats disease, and toxocariasis; requires urgent assessment.
- Retinoblastoma calcification
- CT shows intralesional calcification in most retinoblastomas; a key distinguishing feature from other causes of leukocoria.
- Uveal melanoma ultrasonography
- Choroidal melanoma shows low internal reflectivity on A-scan and a dome-shaped or mushroom-shaped lesion on B-scan.
- Open globe management
- Shield the eye, avoid pressure, give IV antibiotics and tetanus prophylaxis, and proceed urgently to surgical repair under anaesthesia.
- Hyphema management
- Bed rest with head elevation, topical steroids and cycloplegics; avoid NSAIDs and aspirin; monitor for rebleed around days 3–5.
- Fluorescein angiography
- Imaging of retinal vasculature using intravenous fluorescein; shows leakage, non-perfusion, and CNV; rare anaphylaxis and nausea are side effects.
- B-scan ultrasonography
- Useful when the fundus is obscured by cataract or vitreous haemorrhage; detects retinal detachment, tumours, and intraocular foreign bodies.
- Floppy iris syndrome
- Intraoperative iris billowing and prolapse associated with tamsulosin; managed with intracameral phenylephrine, iris hooks, or pupil expansion rings.
- Intracameral cefuroxime
- Antibiotic given at the end of cataract surgery; reduces the risk of postoperative endophthalmitis and is part of standard prophylaxis.
- Number needed to treat
- NNT = 1 / absolute risk reduction; indicates how many patients must be treated to prevent one additional adverse outcome.
- Informed consent
- Voluntary agreement by a competent patient after disclosure of risks, benefits, and alternatives; must be documented in the clinical record.
- Amsler grid
- Patient self-monitoring test for metamorphopsia in macular disease; a new distortion or scotoma warrants urgent review.
- Ishihara plates
- Colour vision test for red-green deficiency; used to detect acquired optic nerve disease and congenital colour blindness.