Understanding Eye Anatomy and Vision Processes

Vision

Dominant sense

relies on light energy.

Photoreceptors

Visual receptor cells that encode light patterns.

Cornea

Clear dome at the front of the eye.

Pupil

Circular opening in the iris center.

Iris

Colored part of the eye surrounding the pupil.

Crystalline Lens

Bends light to focus images on the retina.

Nodal Point (N)

Point where light image is inverted.

Vitreous Humor

Clear gel filling 80% of the eye's volume.

Retina

Layer that registers light and converts signals.

Macula

Central retina area providing the best vision.

Optic Nerve

Transmits visual signals to the brain.

Optic Chiasm

Point where nasal fibers cross to opposite brain.

Optic Tract

Nerve fibers beyond the optic chiasm.

Lateral Geniculate Body

Processes visual information before reaching cortex.

Optic Radiations

Pathway from lateral geniculate to visual cortex.

Visual Pathway

Includes retina, optic nerve, and visual cortex.

Visual Acuity

Clarity of vision, assessed with Snellen Chart.

Snellen Chart

Chart used to measure visual acuity.

Tonometry

Measures intraocular pressure to screen for glaucoma.

Air Puff Tonometry

Non-contact method using a puff of air.

Applanation Tonometry

Contact method using numbing drops and fluorescein.

Refraction Test

Determines need for glasses using various lenses.

Occipital Cortex

Brain area where visual signals are processed.

Tonometer

Device measuring intraocular pressure in the eye.

Schiotz Tonometer

Older tonometer used for applanation method.

Keeler Pulsair Tonometer

Non-contact tonometer using optical and sensor technology.

Applanation

Technique applying pressure to the cornea for measurement.

Corneal Abrasion

Scratch on the cornea, may heal naturally.

Gonioscopy

Examines anterior chamber and drainage angle of eye.

Glaucoma

Condition characterized by increased intraocular pressure.

Goniolens

Lens used in gonioscopy to view drainage angle.

Dilating Drops

Medication used to widen pupils for eye exams.

Ophthalmoscopy

Examination of the fundus of the eye.

Fundus

Back part of the eyeball including retina.

Direct Ophthalmoscope

Handheld device for examining the fundus directly.

Indirect Ophthalmoscope

Head-mounted device providing stereoscopic fundus images.

Slit-lamp Examination

Microscopic examination of front eye structures.

Biomicroscopy

Detailed examination using a slit-lamp microscope.

Optic Disc

Region where optic nerve enters the eye.

Choroid

Layer of blood vessels between retina and sclera.

Anterior Chamber

Space between cornea and iris filled with aqueous humor.

Aqueous Humor

Fluid maintaining intraocular pressure and nourishing tissues.

Corneal Ulcers

Open sores on the cornea, may cause vision loss.

Eye Infection

Infection affecting any part of the eye.

Post-Exam Care

Avoid rubbing eyes and arrange transportation after dilation.

Slit Lamp Exam

Diagnostic tool for various eye conditions.

Macular Degeneration

Chronic condition affecting central vision.

Detached Retina

Retina separates from its base layer.

Cataracts

Clouding of the eye lens affecting clarity.

Corneal Injury

Damage to the eye's surface tissue.

Retinal Vessel Blockage

Obstruction causing vision loss.

Automated Perimetry

Test mapping peripheral vision loss.

Local Anesthetics

Reduce pain perception in the eyes.

Topical Tetracaine

Used for eye exams and surgeries.

Injectable Lidocaine HCl

For examination of the eye.

Mydriatics

Dilate pupils with minimal accommodation effect.

Phenylephrine HCl

Dilates pupils and prevents iris adhesions.

Cycloplegics

Paralyze ciliary muscle for eye examination.

Atropine Sulfate

Reduces pain and photophobia in eye inflammation.

Scleral Assessment

Evaluates sclera color and condition.

Corneal Assessment

Checks cornea for transparency and smoothness.

Blink Reflex

Tests involuntary eye response to stimuli.

PERRLA

Pupils Equal, Round, Reactive to Light and Accommodation.

Normal Pupil Diameter

Typical size ranges from 3 to 5 mm.

Rosenbaum Pocket Vision Screener

Handheld chart for near vision testing.

Accommodation Test

Assesses eye convergence and pupil constriction.

Visual Field

Area where objects can be seen clearly.

Hemianopia

Blindness in one half of vision.

Quadrantanopia

Blindness in one fourth of vision.

Scotomas

Blind spots in the visual field.

Extraocular Muscle Function

Assessment of eye muscle coordination.

Nystagmus

Involuntary eye twitching during lateral gaze.

Six Cardinal Positions of Gaze

Tests eye movement in six directions.

DextroElevation

Right and upward gaze position.

LevoElevation

Left and upward gaze position.

LevoVersion

Left gaze position.

Dextroversion

Right gaze position.

DextroDepression

Right and downward gaze position.

LevoDepression

Left and downward gaze position.

Ishihara Chart

Test for color vision using colored dots.

Conjunctivitis

Inflammation of the conjunctiva, often viral.

Pink Eye

Viral conjunctivitis commonly seen in children.

Allergic Conjunctivitis

Inflammation due to allergic reactions.

Iritis/Uveitis

Inflammation of the uvea layer of the eye.

Interstitial Keratitis

Inflammation of corneal connective tissue.

Retinitis Pigmentosa

Hereditary retinal disease causing progressive vision loss.

Retinitis Pigmentosa (RP)

Progressive eye disease causing vision loss.

Visual Field Loss

Donut-shaped loss leading to severe constriction.

Night Blindness

Difficulty seeing in low light conditions.

Scleritis

Inflammation of the sclera causing redness and swelling.

Sclera

White outer coating of the eye providing support.

Joint Diseases

Conditions like arthritis causing scleritis.

Blood Tests for Scleritis

Used to identify underlying causes of inflammation.

Oral Steroids

Medications like prednisolone for treating inflammation.

Non-Steroidal Anti-Inflammatory Drugs

Medications like Naprosyn for mild scleritis.

Corticosteroids

Anti-inflammatory drugs used to reduce eye inflammation.

Refractive Error

Light rays not focused properly on the retina.

Nearsightedness

Condition corrected with concave lenses for clear near vision.

Farsightedness (Hyperopia)

Condition corrected with convex lenses for clear distance vision.