Opthalmology

Unit 6: Differential Diagnosis of Blurred Vision

Cataract

Examination

  • Measure visual acuity
  • Ophthalmoscopy
    • Diminished red reflex
    • Difficult view of the fundus

Red reflex to view cataract

  • The red reflex is seen by shining the light of an ophthalmoscope into the patient's eye, from about 50 cm centimetres away, and then looking through the viewfinder.
  • It is like the red eye seen when taking photos, which is also caused by light reflected back from the inside of the eye.
  • If cataract interferes with the passage of light into and out of the eye, the red reflex is diminished, or central black areas or lens spokes may be visible with more focal cataract (posterior subcapsular lens opacities and cortical lens opacities, respectively)