Ocular Examinations and Diagnostic Tools

• Examinations and diagnostic tools used to asses patient eyes

Diagnostic Evaluation

Color Vision Testing (Ishihara Polychromatic Plates)

• Determines if a person has normal color vision.
• Plates with primary color dots against secondary color backgrounds make up a booklet.
• Diminished color vision can make hidden shapes impossible to see.
• Individuals with central vision difficulties have trouble identifying colors.

Tonometry

• Measures Intraocular pressure(IOP) to screen for and manage Glaucoma.
• Measuring IOP requires an accurately calibrated applanation tonometer.
• The tonometer measures the pressure needed to flatten the cornea.
• Normal IOP is 12-20 mmHg.
• Topical anesthetic is given because the probe is touching the highly sensitive cornea
• Squeezing eyelids, holding breath, or performing Valsalva can increase IOP.

Slit-Lamp Examination

• Uses a binocular microscope mounted on table
• Allows the examiner to magnify the eye 10 to 40 times to view a real image.
• A narrow beam of light can be used for different parts of the eye.

Ophthalmoscopy

• Provides a magnified view of the retina and optic nerve with the use of light.
• Used to examine the optic disc or posterior of the eyeball.

External Eye Examination

• Evaluates the symmetry and placement of eyelids, pupils, and muscles.
• Cranial nerves III, IV, and VI control eye movement and pupil size.

Six Cardinal Positions of Gaze

• Measures CN III, IV, VI and the extraocular muscles.
• Six cardinal fields
  • Right: extreme lateral, ceiling to floor
  • Left: extreme lateral, ceiling to floor
  • Uncovered eye for movement as focus

Confrontational Visual field test

• Measures the peripheral field of vision.
• Examiner and client sit facing each other
• Clients looks directly into examiner's eyes
• Examiner moves fingers from non - visible area

Pupil Function Test

• Measures normal pupil response to light
• Have clients look into the distance. Shine the light into the eye.
• Darken the room

Eye Disturbances

• Eye Disturbances include: Ectropion, Esotropia, Exotropia, Ptosis, and Exophthalmus

Ectropion

• Eyelid turns outward.
• Happens more often in older adults
• Affects only the lower eyelids
• Exposes the inner eyelid surface, making it prone to irritation.
• Causes include:
  • Relaxation of eyelid tissues (aging)
  • Chronic rubbing
  • Skin damage or cancer
  • Trauma
  • Eyelid or facial surgery
  • Facial nerve palsy
• Symptoms include:
  • Excessive tearing
  • Mucus discharge
  • Irritation and itching
  • Drooping skin
  • Impaired vision
  • Redness
  • Sensitivity to light and wind
• Management:
  • Artificial tears
  • Lubricating ointments
  • Surgery

Entropion

• Eyelid folds inward.
• Eyelashes and skin rub the eyeball, causing discomfort and irritation.
• Causes include:
  • Aging
  • Chronic rubbing
  • Scarring of the inner eyelids
  • Trauma
  • Eyelid or facial surgery
• Symptoms include:
  • Excessive tearing
  • Mucus discharge
  • Surface itching and irritation
  • Impaired vision
  • Redness
  • Sensitivity to light and wind.
• Management
  • Artificial tears or lubricating ointments
  • Use tape or sutures