NBEO Part II key terms

A hand-held grid of straight lines with a central fixation dot that patients view monocularly to self-monitor for metamorphopsia, scotomas, or distortion suggesting macular disease such as choroidal neovascularization or macular edema.

Visual distortion in which straight lines appear bent or wavy. It typically reflects retinal elevation, edema, or traction at the macula and is a key screening symptom for exudative macular degeneration and central serous chorioretinopathy.

A localized area of reduced or absent vision within the visual field, described by its location, size, shape, and density. Central scotomas suggest macular disease; respecting the vertical midline suggests a chiasmal or retrochiasmal lesion.

Loss of the same half of the visual field in both eyes, caused by a lesion posterior to the optic chiasm, such as stroke, tumor, or trauma along the optic tract, radiation, or occipital cortex. It is a non-urgent but neurologically significant finding.

An asymmetric pupillary response in which the affected eye's pupil dilates when light swings to it from the fellow eye, indicating unilateral or asymmetric optic nerve or extensive retinal dysfunction. It is absent in purely media-related vision loss.

Enlargement of the central optic nerve head depression with thinning of the neuroretinal rim, the structural hallmark of glaucomatous damage. Assessment includes cup-to-disc ratio, rim contour, disc hemorrhages, and retinal nerve fiber layer loss.

Examination of the anterior chamber angle using a mirrored or prismatic contact lens to distinguish open from narrow or closed angles, identify peripheral anterior synechiae, and detect pigment or neovascularization before dilation or laser procedures.

Optic neuropathy caused by elevated intraocular pressure when the iris obstructs trabecular outflow in a narrow or closed angle. Acute attacks cause pain, halos, mid-dilated pupil, and corneal edema and require urgent pressure-lowering treatment.

Intraocular pressure above the statistically normal range without detectable glaucomatous optic nerve damage or visual field loss. Patients require periodic monitoring of pressure, disc structure, and fields to detect conversion to glaucoma.

The thickness of the cornea at its center, measured by pachymetry. It influences applanation tonometry readings and is a risk factor in glaucoma: thinner corneas tend to underestimate true pressure and carry higher glaucoma risk.

A contact method of estimating intraocular pressure by measuring the force needed to flatten a fixed area of cornea. Accuracy depends on corneal thickness, curvature, and rigidity, and fluorescein instillation is required.

A measurement of distance visual resolution expressed as the distance at which a patient reads a line relative to the distance at which a standard observer reads it, such as 20/40. It is recorded with and without correction and with pinhole if needed.

The highest visual acuity obtainable with the optimal refractive correction, established by refraction or retinoscopy. It distinguishes refractive blur from ocular disease and is a baseline for monitoring change over time.

A quick screening test in which the patient views through a small aperture that narrows the effective pupil. Improvement in acuity suggests uncorrected refractive error; no improvement suggests media opacity, retinal, or neural cause.

An objective refraction technique in which the examiner neutralizes the movement of the red reflex with lenses to estimate refractive error, especially useful in children, non-verbal patients, and those with unreliable subjective responses.

Refraction performed after paralyzing the ciliary muscle with a cycloplegic drug, revealing latent hyperopia and preventing accommodation from masking refractive error. It is standard in pediatric care and in suspected accommodative esotropia.

An inward deviation that appears when a hyperopic child accommodates to clear a blurred image. It is treated with full plus correction, sometimes bifocals, and amblyopia or suppression therapy as indicated.

Reduced best-corrected acuity in one or both eyes caused by abnormal visual experience during development, such as strabismus, anisometropia, or deprivation, without structural cause. Treatment relies on refractive correction, occlusion, or atropine penalization.

A clinically significant difference in refractive error between the two eyes that can cause aniseikonia and, in children, amblyopia of the more ametropic eye. It may be managed with contact lenses or refractive surgery.

A binocular vision test in which each eye is alternately covered while the uncovered eye is observed for movement. It distinguishes manifest tropia from latent phoria and reveals the direction and size of deviation.

The perception of depth from slight differences between the images received by the two eyes. Its presence and grade on tests such as random-dot stereograms confirm some degree of binocular sensory fusion.

The closest point at which the two eyes can maintain single binocular vision while a target approaches. A remote or receding near point suggests convergence insufficiency, a common cause of near asthenopia.

Systematic description of lens opacity by type, nuclear color or density, cortical spokes, and posterior subcapsular changes, using a standardized scale such as LOCS III. It informs surgical timing and documentation.

Clouding of the residual lens capsule months to years after cataract surgery, causing reduced acuity and glare. It is treated with neodymium-YAG laser capsulotomy, and patients should be counseled about recurrence and retinal detachment risk.

Infection within the eye, most often after surgery or intravitreal injection, presenting with pain, marked vision loss, hypopyon, and vitritis. It is an emergency requiring immediate vitreous sampling and intravitreal antibiotics.

A layer of white blood cells settled in the inferior anterior chamber, indicating severe intraocular inflammation or infection such as endophthalmitis or uveitis. Its presence with pain and vision loss warrants urgent referral.

Scheduled and urgent evaluation after ocular surgery covering wound healing, intraocular pressure, inflammation, infection signs, refractive outcome, and medication tapering, with clear instructions on symptoms that require immediate contact.

A laser procedure that applies burns to the trabecular meshwork to improve aqueous outflow in open-angle glaucoma. It is an option for patients with inadequate pressure control or poor adherence to topical therapy.

Microvascular retinal damage from chronic hyperglycemia, classified as nonproliferative or proliferative and complicated by macular edema. Findings include microaneurysms, hemorrhages, hard exudates, and neovascularization; control of glucose and blood pressure reduces risk.

Retinal vascular changes from elevated blood pressure, including arteriolar narrowing, AV nicking, flame hemorrhages, cotton-wool spots, and papilledema in malignant hypertension. Severe grades warrant urgent systemic evaluation.

Bilateral optic disc swelling caused by raised intracranial pressure, often with headache, transient visual obscurations, and enlarged blind spots. It requires urgent neuroimaging and, in some cases, lumbar puncture.

Ischemic optic nerve damage from giant cell arteritis, causing sudden vision loss, often with jaw claudication, scalp tenderness, or polymyalgia symptoms in older adults. It is an emergency requiring immediate high-dose corticosteroids.

Imaging in which intravenous fluorescein dye is photographed as it passes through retinal vessels, revealing leakage, nonperfusion, neovascularization, and macular edema. It guides treatment decisions and requires screening for dye allergy.

Non-invasive cross-sectional imaging of the retina and optic nerve using low-coherence light, used to quantify macular edema, subretinal fluid, and retinal nerve fiber layer thinning. It supports diagnosis and longitudinal monitoring.

Magnified examination of the anterior segment and, with auxiliary lenses, the posterior segment. It allows assessment of lids, conjunctiva, cornea, anterior chamber cells and flare, iris, and lens with adjustable illumination and magnification.

Scattering of light by protein that has leaked into the aqueous humor during blood-aqueous barrier breakdown. Graded with a narrow slit beam, it signals intraocular inflammation and is monitored alongside cells during uveitis treatment.

Measurement of intraocular pressure by contact or non-contact methods, such as Goldmann applanation, rebound, or air-puff devices. Serial readings, not single values, guide glaucoma management decisions.

Perimetric mapping of the patient's sensitivity across the visual field, commonly by automated static threshold testing. It detects glaucomatous defects and neurologic field loss and is interpreted with reliability indices and optic disc findings.

A structured program of magnification devices, lighting, contrast enhancement, eccentric viewing training, and adaptive strategies that helps patients with irreversible vision loss perform daily tasks and maintain independence.

The process of explaining a procedure's purpose, risks, benefits, and alternatives, including no treatment, and confirming that the patient voluntarily agrees. It must be documented and revisited when circumstances change.

The professional obligation to send a patient for evaluation when findings exceed the clinician's scope, competence, or available equipment, with timely communication and documentation. Failure to refer can constitute negligence.

Clear, timely exchange of clinical information with physicians, pharmacists, therapists, and other providers through referral letters, phone contact, and shared records, improving coordination and reducing medication and management errors.