Eye Exam 2

Structure and Function of the Eye

  • The eye is a complex organ comprising both external and internal structures that work together to create vision.

    • Eyebrows and eyelashes protect the eyes from debris and sweat.

    • Eyelids serve to protect and lubricate the surface of the eye.

    • Conjunctiva: A thin membrane that covers the front of the eye and the inner surfaces of the eyelids.

    • Lacrimal glands produce tears for lubrication and protection.

Diagnostics

  • Visual Acuity Tests: Various methods to measure visual clarity.

    • Snellen Eye Chart: Used to test distant vision.

    • Tumbling E Chart: An alternative chart for those who cannot read standard letters.

    • Rosenbaum Screening Card: Used for near vision assessment.

  • Comprehensive dilated eye examination: Provides a direct view of the retina and internal structures of the eye.

  • Tonometry: A device used to measure intraocular pressure (IOP).

Health History

  • Past Medical History: Important to assess for any issues.

    • Common conditions include:

    • Cataracts: Clouding of the lens, affecting vision.

    • Glaucoma: Increased intraocular pressure leading to optic nerve damage.

    • Macular degeneration: Loss of vision due to damage to the retina.

    • Eye injury or surgery: Such as LASIK, which reshapes the cornea. Cataract surgery involves removing the cloudy lens and implanting an artificial one.

  • Family History: Inquiry into any hereditary eye disorders.

  • Health Promotion and Eye Exams:

    • Recommended frequency for eye exams.

    • Implementation of glaucoma tests and the use of protective eyewear, especially for specific occupations.

Visual Impairments/Vision Loss Assessment

  • Evaluate difficulty in distance or near vision and any decrease in visual acuity or clarity.

  • Investigate color vision defects and inquire about any use of glasses or contact lenses.

  • Assessment of how impaired vision affects daily living activities.

  • Explore symptoms:

    • Questions regarding drainage, redness, and allergies.

    • Diplopia: Double vision.

    • Photophobia: Light sensitivity.

    • Night blindness: Difficulty seeing in low light.

    • Eye pain, headaches, or dry eyes, and excessive tearing.

  • Observations for:

    • Symptoms like floaters, flashing lights, or sudden changes in vision requiring immediate attention.

Sequence of Eye Assessment

  1. Inspect the eye

  2. Assess visual acuity

  3. Conduct the confrontation test for peripheral vision

  4. Assess for convergence and accommodation

  5. Evaluate pupil size and consensual response

  6. Assess cardinal fields of gaze

Inspecting the Eyes

  • Purpose: To assess the anterior structures of the eye.

  • Equipment: A light source for inspection.

  • Steps:

    • Inspect eyelids for complete closure and signs of color, redness, swelling, lesions, or drainage.

    • Examine the eyelashes for distribution, drainage, and crusting.

    • Check eyebrows for symmetry and skin condition.

    • Evaluate the cornea for smoothness and clarity; lens for clarity and shape; sclera for color and smoothness.

    • Inspect conjunctiva and lacrimal ducts for location of mucus and swelling.

Normal Findings in Eye Assessment

  • Eyes symmetrical with no protrusion.

  • No redness or drainage present.

  • Eyelids close completely with no drooping (ptosis).

  • Eyelashes and eyebrows are evenly distributed and free of debris.

  • Clear cornea and lens without opacities.

  • Pupils equal in size, and properly functioning iris controls pupil size.

  • Sclera appears white; conjunctiva is pink and moist.

  • The lacrimal duct is unobstructed and clear.

  • Palpebral fissures are equal bilaterally.

  • Absence of abnormal involuntary movements.

Abnormal Findings in Eye Assessment

  • Ptosis: Drooping of the upper eyelid.

  • Blepharitis: Inflammation of the eyelid margins.

  • Blocked lacrimal duct: Leads to excessive tearing or dryness.

  • Cataract: Lens opacity.

  • Conjunctivitis: Inflammation of the conjunctiva.

  • Corneal abrasion: Scratch on the cornea.

  • Subconjunctival hemorrhage: Bleeding underneath the conjunctiva.

  • Nystagmus: Involuntary eye movement.

  • Strabismus: Misalignment of eyes.

  • Ectropion: Eversion of the eyelid.

  • Entropion: Inversion of the eyelid.

  • Exophthalmos: Protrusion of the eyeball, potentially seen in hyperthyroidism.

  • Hordeolum (stye): Inflammation of sweat glands in eyelid.

  • Scleral jaundice (icterus): Yellowing of the sclera, indicating liver issues.

  • Pterygium: Growth on conjunctiva that can affect vision.

  • Periorbital edema: Swelling around the eyes.

  • Sunken eyes: Indicating dehydration or illness.

  • Floaters and vision loss.

Assessing for Visual Acuity

  • Purpose: To measure vision detail at near and far distances.

  • Equipment:

    • Snellen chart: For distance vision; Rosenbaum card: For near vision.

    • If the patient wears corrective lenses (not reading glasses), they should be worn during eye tests.

  • Procedure:

    • Patient stands 20 feet away from the Snellen chart, covering one eye with an opaque card.

    • Patient reads lines left to right.

    • Document the last line read correctly and the number of letters missed.

    • Example notation: 20/40-2 means the patient is 20 feet from the chart and missed 2 letters on the line marked 40.

Visual Acuity Findings

  • Normal Findings: 20/20 vision indicates good eyesight; any lower denominator indicates poorer visual acuity.

  • Abnormal Findings: Can include:

    • Myopia: Nearsightedness (difficulty seeing distant objects).

    • Hyperopia: Farsightedness (difficulty seeing near objects).

    • Presbyopia: Age-related difficulty in focusing on near objects.

    • Legal blindness: Defined as vision of 20/200 or worse, significantly impacting daily functions.

Testing for Convergence and Accommodation

  • Purpose: To assess the eye's ability to focus on near objects (accommodation) and how both eyes move together (convergence).

  • Procedure:

    • Hold an object about 14 inches from the patient's eyes and instruct them to focus on it for 30 seconds.

    • Move the object toward the nose to evaluate eye convergence and pupil constriction.

  • Interpretation of Results:

    • Normal: Pupils constrict and converge simultaneously. Abnormal findings include failure of pupils to constrict or converge appropriately.

Inspecting Pupil Size & Consensual Response

  • Purpose: To evaluate the pupillary light reflex and optic pathway integrity.

  • Procedure:

    • Stand in front of the patient and use a penlight to check pupils for:

    • Color

    • Shape

    • Symmetry

    • Measure pupil size in millimeters, assess both direct and consensual reactions to light.

  • Normal Findings: Pupils should be equal, round, and reactive to light and accommodation (PERRLA).

  • Abnormal Findings: Includes anisocoria (unequal pupils), mydriasis (fixed and dilated), and miosis (abnormally constricted).

Six Cardinal Positions of Gaze

  • Procedure:

    • Hold a penlight or finger 12 to 14 inches away from the patient's face while instructing them to keep their head still.

    • Move the object in a wide “H” or “Star” pattern, allowing for observation of eye movements.

  • Normal Findings: Smooth, coordinated eye movements without any involuntary movements.