ICO Advanced flashcards

31 cards. Read the term and the definition here. The deck at the top of this page is optional.

Central corneal thickness

Average central corneal thickness is about 540 micrometers. Thinner corneas make applanation tonometry overestimate intraocular pressure and are associated with a higher risk of glaucoma progression.

Goldmann applanation tonometry

The reference standard method for measuring intraocular pressure. Its readings are influenced by central corneal thickness, corneal curvature, and astigmatism, so results must be interpreted with those factors in mind.

Normal-tension glaucoma

A form of glaucomatous optic neuropathy with characteristic disc cupping and visual field loss despite intraocular pressure within the statistically normal range, roughly 10 to 21 millimeters of mercury.

Gonioscopy

The reference standard examination for grading the anterior chamber angle using a contact lens and slit lamp. It distinguishes open from closed angles and identifies peripheral anterior synechiae.

Acute angle-closure glaucoma

An ophthalmic emergency with severe eye pain, headache, nausea, halos, a mid-dilated fixed pupil, corneal edema, markedly elevated intraocular pressure, and a closed angle on gonioscopy.

Glaucomatous disc cupping

Optic disc changes suggesting glaucoma include a cup-to-disc ratio above 0.5, asymmetry greater than 0.2 between eyes, disc hemorrhage, and retinal nerve fiber layer thinning with field loss respecting the vertical midline.

Nuclear sclerotic cataract

Age-related hardening and yellowing of the lens nucleus causing gradual painless blurring and glare. Surgery is indicated when visual limitation interferes with daily function or occupational needs.

Proliferative diabetic retinopathy

Advanced diabetic retinopathy with neovascularization of the disc or elsewhere. It risks vitreous hemorrhage and tractional retinal detachment; earlier stages show microaneurysms, hemorrhages, hard exudates, and cotton-wool spots.

Wet macular degeneration

The neovascular form of age-related macular degeneration, with choroidal neovascular membranes causing subretinal fluid or hemorrhage. Sudden metamorphopsia on Amsler grid testing suggests conversion to this form.

Rhegmatogenous retinal detachment

Detachment caused by a retinal break allowing fluid into the subretinal space. It presents with painless flashes, new floaters, and a curtain-like field defect, and requires urgent ophthalmology referral.

Red eye warning signs

Pain, photophobia, reduced vision, ciliary flush, and a fixed pupil suggest serious ocular disease such as keratitis, uveitis, or acute angle closure rather than simple conjunctivitis.

Bacterial versus viral conjunctivitis

Bacterial conjunctivitis typically shows purulent discharge and glued lashes with papillary reaction. Viral conjunctivitis shows watery discharge and follicular reaction, is often bilateral, and may follow an upper respiratory infection.

Contact lens keratitis

Corneal infection associated with contact lens wear, especially Pseudomonas species. An epithelial defect with infiltrate and photophobia requires urgent review and removal of the lens.

Anterior uveitis

Inflammation of the iris and ciliary body causing pain, photophobia, consensual photophobia, ciliary flush, and cells with flare in the anterior chamber. It is associated with HLA-B27 spondyloarthritis and sarcoidosis.

Scleritis

Severe boring ocular pain, often worse at night, with a violaceous scleral hue and globe tenderness. It may accompany rheumatoid arthritis and can threaten vision.

Orbital cellulitis

Infection of orbital tissues presenting with proptosis, ophthalmoplegia, pain on eye movement, and fever. It is an emergency because of the risk of cavernous sinus thrombosis and intracranial extension.

Papilledema

Bilateral optic disc swelling caused by raised intracranial pressure. Visual acuity is typically spared early, but the blind spot enlarges and transient visual obscurations may occur.

Optic neuritis

Unilateral painful vision loss worsened by eye movement, with a relative afferent pupillary defect and dyschromatopsia. It is strongly associated with multiple sclerosis.

Horner syndrome

Ptosis, miosis, and anhidrosis caused by disruption of the sympathetic pathway to the eye. A painful Horner syndrome suggests carotid dissection and requires urgent evaluation.

Relative afferent pupillary defect

An asymmetric pupillary response detected with the swinging flashlight test, indicating optic nerve disease or extensive retinal damage on the affected side. It is absent in simple refractive error.

Pinhole visual acuity testing

A quick test using a pinhole occluder to distinguish reduced acuity caused by refractive error from that caused by media opacity or retinal or optic nerve disease.

Amsler grid

A grid chart used to detect central and paracentral metamorphopsia and scotomas. It screens for macular disease and helps monitor the neovascular form of macular degeneration.

Fluorescein corneal staining

Application of fluorescein dye viewed under cobalt blue light to identify corneal epithelial defects and ulcers, which appear as bright green areas against the darker cornea.

Optical coherence tomography

Cross-sectional retinal imaging used to detect macular edema, subretinal fluid, and epiretinal membranes, and to measure retinal nerve fiber layer thinning in glaucoma.

Ocular ultrasound

B-scan imaging used when the fundus view is obscured, such as by dense cataract or vitreous hemorrhage, to assess for retinal detachment or an intraocular mass.

Fluorescein angiography

Intravenous fluorescein imaging of the retinal vasculature that identifies leakage, neovascularization, and nonperfusion. It carries a small risk of anaphylaxis and requires informed consent.

Chemical ocular burn

An eye injury requiring immediate copious irrigation with saline or water before further examination. Alkali burns are more damaging than acid burns because they penetrate ocular tissues more deeply.

Open globe injury

A penetrating eye injury suggested by a peaked pupil, shallow anterior chamber, hypotony, uveal prolapse, or a positive Seidel test. Pressure must be avoided; shield the eye and refer urgently.

Central retinal artery occlusion

Sudden painless monocular vision loss with a pale retina and cherry-red macula. It is a stroke equivalent requiring urgent stroke workup and cardiovascular risk assessment.

Giant cell arteritis

In patients over 50 with headache, jaw claudication, scalp tenderness, and visual symptoms, high-dose corticosteroids are started immediately and temporal artery biopsy arranged without delaying treatment.

Endophthalmitis

Acute pain, redness, and vision loss after intraocular surgery or injection, often with hypopyon. It is an emergency requiring intravitreal antibiotics and urgent ophthalmology involvement.