Vision and Hearing
Anatomy of the Eye
Cornea: Transparent front part of the eye that covers the iris, pupil, and anterior chamber.
Macula Lutea: Small yellow area near the center of the retina that is responsible for detailed central vision.
Iris: Colored part of the eye that controls the size of the pupil and the amount of light that enters.
Lens: Transparent structure behind the iris that focuses light onto the retina.
Anterior Chamber: Fluid-filled space between the cornea and the iris.
Canal of Schlemm: Structure that drains aqueous humor from the anterior chamber.
Ciliary Body: Structure that adjusts the lens shape for focusing and produces aqueous humor.
Posterior Chamber: Space between the iris and lens filled with aqueous humor.
Bony Orbit: The bony cavity in which the eye is situated.
Retina: The innermost layer of the eye that contains light-sensitive cells (photoreceptors) that send visual signals to the brain.
Uvea: The middle layer of the eye, including the iris, ciliary body, and choroid.
Sclera: The white outer coating of the eyeball.
Developmental Expectations for Vision and Hearing in Children
Vision Assessment Parameters:
Infant:
Ability to follow objects.
Corneal (blink) reflex.
Ability to turn to light stimuli.
Toddler:
Corneal light reflex.
Cover test.
Smooth ocular movements.
Preschooler:
Hand-eye coordination.
Snellen E chart or Allen figures (or modification).
School age:
Visual acuity testing every 1-2 years.
Adolescent:
Visual acuity testing every 1-2 years.
Hearing Assessment Parameters:
Infant:
Startle reflex at hearing sound (at birth).
Toddler:
Ability to track sounds (3-6 months).
Ability to recognize sounds (6-8 months).
Ability to locate sounds (8-12 months).
2 years:
Ability to react to soft sounds (whispers).
Ability to form a noun-verb sentence.
School age:
Ability to follow simple directions.
Awareness of pitch and tone.
Pure tone audiometry (starting at age 4).
Understandable language with increasing vocabulary.
Adolescent:
Pure tone audiometry at ages 6, 8, and 11 years.
Pure tone audiometry at ages 14 and 18 years.
Vision Disorders
Definition: Disorders that interfere with vision include structural problems, infections or inflammation, traumatic injuries, and inner eye conditions.
Types of Disorders:
Hyperopia: Farsightedness, where distant objects are seen clearly but close objects are blurry.
Myopia: Nearsightedness, where close objects are seen clearly but distant objects are blurry.
Astigmatism: Results in blurred vision due to an irregular shape of the cornea or lens; may cause headaches and vertigo.
Nystagmus: Characterized by rapid, irregular eye movements, impacting vision.
Amblyopia: Decreased vision in one eye; E chart may show 20/50 vision in affected eye and potentially 20/100 in other.
Color Vision Deficit: Difficulty in distinguishing colors; testing involves color plates or discs
Therapeutic Techniques for Vision Disorders
Refractive Errors: Treated with corrective lenses, contact lenses, LASIK, or PRK.
Nystagmus: Referred to primary care for determination of cause.
Amblyopia: Treated with corrective lenses, patching, or possibly LASIK.
Color Vision Deficit: No medical therapy exists; emphasis on patient education.
Assessing Structural Problems of the Eye
Coloboma: Characterized by a keyhole-shaped iris, identifiable on physical exam.
Hypertelorism: Assess distance between pupils against standard age measurements.
Ptosis: Manifested by eyelid drooping; signs include forehead wrinkling and raised eyebrows.
Strabismus: Identifiable through muscle imbalance of the eyes past 6 months of age.
Therapeutic Techniques for Structural Problems of the Eye
Coloboma: Requires referral to an ophthalmologist.
Hypertelorism: No therapy required.
Ptosis: May require surgical correction.
Strabismus: May require exercises, corrective lenses, or surgery depending on the strength of eye muscles.
Assessing Infection and Inflammation of the Eye
Common Disorders:
Stye: Infection of a ciliary gland.
Chalazion: Low-grade tumor due to retained secretions.
Blepharitis: Infection often linked to seborrheic dermatitis.
Conjunctivitis Types:
Acute Catarrhal Conjunctivitis: Often caused by bacteria such as Haemophilus influenzae.
Herpetic Conjunctivitis: Associated with herpes simplex infection.
Allergic Conjunctivitis: Response to allergens; symptoms include redness and severe itching.
Assessment Criteria for Infectious and Inflammatory Eye Disorders
Signs and Symptoms of Infection:
Stye shows localized pain and lid edema.
Chalazion is a small, painless nodule.
Blepharitis may show reddened margin with crusts.
Conjunctivitis presents with watery eyes and light sensitivity.
Treatment Strategies for Eye Infections
Stye: Hot compresses, antibiotics, and surgical drainage if necessary.
Chalazion: May resolve spontaneously; surgical evacuation if needed.
Blepharitis: Antibiotic ointments and good hygiene.
Conjunctivitis: Depends on the cause; can involve antibiotics or antihistamines for allergies.
Assessing Inner Eye Conditions
Cataract:
In Young Children: Red reflex appears white.
In Older Children: Blurred vision reports.
Congenital Glaucoma: Symptoms include enlarged corneas and possible pain or tearing.
Therapeutic Techniques for Inner Eye Conditions
Cataracts: Surgical removal and replacement with an intraocular lens.
Congenital Glaucoma: May require surgical interventions like trabeculotomy.
Structure of the Ear
External Ear (Auricle or Pinna): Visible part that collects sound waves.
Middle Ear: Contains malleus, incus, and stapes (ossicles) which transfer sound vibrations to the inner ear.
Inner Ear: Contains cochlea, auditory tubes, and balance structures (semicircular canals).
Disorders of the Ear
Types:
External Otitis: Inflammation and infection of the ear canal.
Impacted Cerumen: Accumulation of earwax causing blockages.
Acute Otitis Media: Ear infection often following respiratory illnesses.
Otitis Media With Effusion: Fluid build-up behind the eardrum leading to pressure and muffled hearing.
Assessing Disorders of the Ear
External Otitis: Symptoms include pain on contact, inflammation, and possible swelling.
Impacted Cerumen: Visual signs of wax blocking the ear canal.
Acute Otitis Media: Sharp ear pain, signs of infection, and immobility of the tympanic membrane.
Otitis Media With Effusion: Characterized by fluid behind the eardrum, leading to pressure feelings and muffled sounds.
Levels of Hearing Impairment
Decibel Levels (dB):
Slight (<30): Unable to hear whispers.
Mild (30-50): No speech impairment but may not be aware of hearing difficulty.
Moderate (55-70): Difficulty hearing normal conversation; may show early speech loss.
Severe (70-90): Difficulty hearing most sounds, requires speech therapy.
Profound (>90): Near-complete hearing loss; hears only loud sounds.
Therapeutic Techniques for Hearing Impairment
Hearing Aids: Devices assisting in amplification of sound.
Cochlear Implants: Surgical implant devices for those with severe hearing loss.
Speech Therapy: To improve communication skills and speech clarity.
Therapeutic Techniques for Disorders of the Ear
External Otitis: Treatment may include ear drops for inflammation/infection and analgesics.
Impacted Cerumen: Use of softening agents or dilute hydrogen peroxide.
Acute Otitis Media: Generally resolves on its own; antibiotics if necessary.
Otitis Media With Effusion: Depending on severity, treatments may include antihistamines or surgical removal of blocking adenoids.
Additional Notes from Questions and Rationale
Question #1: Approach to a blind child should be to call their name first and then introduce yourself to avoid startling them.
Question #2: The common cause of external otitis is swimming; emphasizing education on proper ear care.
Question #3: Understanding myringotomy precautions is crucial; the correct response is to ensure that the child does not swim with tubes to prevent infections.