Ophthalmology Assessment of the visual system

MEDICAL AND SURGICAL NURSING

OPHTHALMOLOGY

ASSESSMENT OF THE VISUAL SYSTEM

A complete visual examination includes the following,

  1. Patient interview (history collection).
  2. Physical examination.
  3. Other diagnostic tests uniquely for the eye.

a.)    History collection:-

The nurse can assess the patient by concentrating on the following issues,

  • Patient’s recent changes in visual acuity.
  • Usage of glasses or lenses by the patient.
  • Questions on the signs and symptoms like blurring of vision, floaters, pain, headaches, redness, discharges etc.
  • Whether the patient uses any eye protective equipments like goggles, coolers.
  • Any recent history of head injury, loss of conscious, direct trauma, or infections.
  • Any family history of eye disorders like cataract, glaucoma, hypertension, STD etc.

b.)   Physical examination:-

Physical examination of the eye includes the inspection of the visual system and its external structures.

  • Facial and ocular expression – eye prominence, and the eye expression.
  • Eyelids and conjunction – symmetricity, any oedema, itching and irritation, redness, ptosis, entropion or ectropion, hordeolum, chalazion etc.
  • Sclera – colour whether white or yellow.
  • Cornea – clarity, dryness, vascularity.
  • Lacrimal duct – tears, swelling, growths.
  • Iris and pupils – irregularities in colour, shape, size and reaction to light.PERRLA-  pupils equal, regular reacting to light and accommodation.
  • Anterior chamber – depth , presence of blood or pus.
  • Lens – transparency, opacity etc.
  • Visual acuity with and without glasses.
  • Intra ocular pressure measurement.
  • Range of motion of the extra ocular muscles.
  • Optic nerve activity.

 The physical assessment of the normal  visual system includes,

  • Vision 20/20 with no double vision.
  • External eye structures devoid of any deformities or lesions.
  • Lacrimal apparatus without any drainage.
  • Clear conjunctiva and lens.
  • White sclera.
  • PERRLA
  • EMOI
  • Sharp disc margins.
  • No spots or hemorrhage in the retinal vessels.

C.)  Other diagnostic tests:-

  • Visual acuity testing:

It helps to determine the near and distant visual acuity of the patient by using the snellan’s chart  for distance vision test and Jaoeger’s test for near vision testing.

  • Extraocular mjuscle testing:

This test is performed to know whether the patient’s ocular muscles are functioning in a  normal manner without hypoactivity or hyperactivity.

  • Confrontation visual test:

This test helps to interpret the patient has full field of vision without the scotomas.

  • Pupil function test:

It helps to find the pupillary response of the patient.

  • Tonometry:

  It helps to measure the intra ocular pressure of the patient.

  • Slit- lamp microscopy:

It provides a magnified view of the conjunctiva, sclera, cornea and the anterior chamber, iris, lens etc.

  • Ophthalmoscopy:

It  gives the magnified view of the retina and the optic nerve head.

  • Colour vision testing:

It helps to find out the ability of the patient to distinguish colours.

  • Stereopsis testing:

It helps to determine the patient’s ability to see objects in all the three dimensions and the perceptual powers.

  • Keratometry:

It helps to measure the curvature of the cornea.

  • Retinoscopy:

It  helps to measure the refractive errors of the eye.

  • Refractometry:

It also helps to determine the refractive errors of the eye.

  • Visual field perimetry:

This test gives us a detailed mapping of the visual field.

  • Ultrasonography:

It helps to diagnose ocular tumours, retinal detachments or foreign bodies in the eye.

  • Fluorescein angiography:

It provides information about the blood flow through RPE and retinal vessels and to find out areas of diabetic retinopathy.

  • Amsler grid:

It is used to identify any macular disorders.

  • Schirmer tear test:

This test is used to measure the volume of tear produced in a specified time.

  • Tests used to assess the function of visual pathway are,
  1. Electroretinogram  (ERG).
  2. Electrooculogram (EOG).
  3. Dark adaptometry.
  4. Visual evoked potential.

These tests are used to diagnose occlusions, toxic drug exposure, retinal diseases and foreign body in the eye.