Eye Disorders: Disorders of the Cornea, Anterior Chamber, Lens, and Globe

Vocabulary flashcards covering the pathophysiology, clinical presentations, diagnostic findings, and treatment protocols for disorders of the cornea, anterior chamber, lens, and globe.

Aqueous Humor Flow Pathway

The normal intraocular fluid circulation route: aqueous humor is secreted by the ciliary processes into the posterior chamber, passes through the pupil into the anterior chamber, traverses the trabecular meshwork, and drains into Schlemm's canal (scleral venous sinus).

Acute Angle-Closure Glaucoma

An ophthalmic emergency caused by closure of the anterior chamber angle by the iris contacting the cornea, physically obstructing aqueous humor outflow and causing rapid, vision-threatening intraocular pressure elevation ($>40\,\text{mm}\,\text{Hg}$), severe unilateral eye pain, headache, nausea, a cloudy cornea, and a fixed, mid-dilated pupil.

Laser Peripheral Iridotomy

The definitive surgical management for acute angle-closure glaucoma involving the creation of a full-thickness hole in the peripheral iris using a laser, typically performed within $24\text{ to }48\,\text{hours}$ after resolution of the acute attack.

Mydriasis (Glaucoma Precipitation)

Pupillary dilation—triggered by dark environments, emotional fear, anticholinergic medications, sympathomimetics, or decongestants—that causes the iris to bunch into the drainage angle, precipitating acute angle-closure glaucoma in predisposed individuals.

Chronic Open-Angle Glaucoma (POAG)

A chronic progressive optic neuropathy caused by impaired aqueous humor drainage through the trabecular meshwork despite an anatomically open angle, producing gradual intraocular pressure elevation (normal is $8\text{ to }21\,\text{mm}\,\text{Hg}$) and painless, progressive bilateral peripheral visual field loss.

Optic Disc Cupping

A characteristic fundoscopic sign of chronic open-angle glaucoma showing progressive enlargement of the cup-to-disc (C/D) ratio (e.g., advancing from $0.2$ to $0.7$ or $0.99$), neuroretinal rim thinning, and rim notching due to optic nerve fiber loss.

Glaucoma Eyedrop Bottle Cap Color Coding

Standardized ophthalmic bottle cap color indicators: turquoise for prostaglandin analogues, purple for alpha-2 adrenergic agonists, dark blue for beta-blocker combinations, orange for carbonic anhydrase inhibitors, and yellow for beta-blockers.

Prostaglandin Analogues

First-line topical medical agents for chronic open-angle glaucoma (including latanoprost, bimatoprost, and travoprost) with turquoise caps that decrease intraocular pressure by increasing uveoscleral aqueous outflow.

Uveitis Anatomical Classification

The anatomical categorization of uveal inflammation: anterior uveitis (iritis affecting the iris), intermediate uveitis (vitreous humor), posterior uveitis (choroid and retina), and panuveitis (involving the anterior chamber, vitreous, and posterior segments simultaneously).

Cells and Flare

The hallmark slit-lamp biomicroscopy finding required for diagnosing anterior uveitis, representing inflammatory leukocytes ('cells') and protein transudation ('flare') suspended in the aqueous humor of the anterior chamber.

Hypopyon

A layered collection of white blood cells and purulent exudate settling in the inferior dependent portion of the anterior chamber, seen in severe anterior uveitis, corneal ulcers, and bacterial keratitis.

Cataract

Pathological opacification and clouding of the crystalline lens of the eye—accounting for $90\%$ of acquired cases from aging and representing the most common cause of blindness worldwide—manifesting as gradual, painless reduction in visual acuity, night blindness, and glare around lights.

Corneal Abrasion

A mechanical scratch or defect confined to the corneal epithelium that causes acute foreign body sensation, severe pain, photophobia, and excessive lacrimation, demonstrating intense uptake on fluorescein staining under a cobalt blue slit-lamp beam or Wood's lamp.

Corneal Ulcer

A severe, deep tissue defect extending through multiple corneal layers characterized by an epithelial loss with an underlying inflammatory stromal infiltrate and hazy white base; most frequently secondary to infection associated with improper contact lens wear.

Pseudomonas Keratitis

A fulminant, rapidly progressive bacterial corneal infection frequently occurring in contact lens wearers, characterized by thick mucopurulent discharge, hypopyon, and stromal necrosis capable of causing corneal perforation within $2\text{ to }5\,\text{days}$.

Eye Patching Restriction

The clinical rule specifying that eye patching is strictly avoided in contact lens wearers or in corneal ulceration due to high risk of accelerating virulent bacterial infections, and is otherwise restricted to non-infectious abrasions $>5\,\text{mm}$ for a maximum of $24\,\text{hours}$.

Dendritic Ulcer (HSV Keratitis)

A linear, branching epithelial lesion with characteristic terminal bulbs revealed by fluorescein staining, representing corneal epithelial reactivation of Herpes Simplex Virus type 1 (HSV-1).

Hutchinson's Sign

The appearance of vesicular dermatomal lesions on the tip, side, or root of the nose indicating involvement of the nasociliary branch of the ophthalmic division of the trigeminal nerve ($V_1$), strongly correlating with ocular involvement in Herpes Zoster Ophthalmicus.

Pseudodendritic Lesions

Atypical epithelial corneal lesions seen in Herpes Zoster Ophthalmicus (HZO) that appear thinner and less well-defined than HSV lesions and lack terminal bulbs.

Chemical Keratitis (Alkali vs. Acid)

Corneal chemical injuries wherein alkali agents penetrate rapidly and deeply via lipid membrane saponification, while acid agents produce coagulative necrosis that forms an insoluble protein barrier limiting tissue penetration.

Ocular Chemical Decontamination

Immediate and continuous irrigation of the eye using saline or water through an eye flush or irrigation lens (Morgan lens) continued until the conjunctival fornix pH neutralizes to approximately $7$.

Ultraviolet (Actinic) Keratitis

Bilateral corneal superficial epithelial burns caused by UV light exposure ('welder's flash' or 'snow blindness'), presenting $6\text{ to }12\,\text{hours}$ post-exposure with severe ocular pain, photophobia, and diffuse bilateral punctate fluorescein staining on slit lamp examination.

Vitreous Hemorrhage

The extravasation of blood into the vitreous chamber secondary to retinal tears, diabetic or sickle cell retinopathy, trauma, or anticoagulation, presenting clinically with sudden, painless visual loss, floaters, and an obscured or absent fundoscopic red reflex.