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Visual problems


Visual problems may be due to refractive errors, damage to the eye or optic nerve. This may be an indication of underlying diseases such as diabetes or hypertension.


  • Look for abnormalities of the eye

  • Determine visual acuity accurately in both eyes by Snellen chart

  • If vision is diminished, (less than 6/12), perform the following 

Pin hole test

  • Make a hole of about 1mm wide in a piece of dark/black paper – you can push a hole in a paper or card with a pen tip

  • Ask the patient to look through this hole at the Snellen chart

  • If vision improves, this means that the patient has a refractive error 

Red Reflex Test

The patient looks past the examiners head focusing on a distant target.

  • With the ophthalmoscope at 0 (zero) the examiner keeps close to his eye and then focuses the beam of light so that it falls on the pupillary area of the cornea

  • The examiner stands about 60 cm away from the patient.

  • In normal individuals, the examiner should be able to see a red or pink color (reflex) through the pupil which comes from the retina. 

Significance of absent red reflex

 If there is history of trauma or diabetes, the absence of a red reflex is probably due to:

  • Retinal detachment

  • A vitreous haemorrhage

  • Mature cataract

 If there are cataracts, one usually sees:

  • Black shadows against the red reflex in immature cataract, or

  • Absence of red reflex in mature cataracts 

In a >50 years of age with no history of trauma, diabetes or previous eye disease, an absent red reflex is often due to cataract formation, especially with decreased visual acuity. 

Note: Associated diabetes or hypertension should be adequately managed with referral, as surgery can only be considered with appropriately managed systemic disease 



Urgent within 12–24 hours

  • Sudden loss of vision in one or both eyes

  • Pain or redness in one eye only especially with visual and pupillary abnormalities

  • Recent proptosis of one or both eyes or enlargement of the eye (buphthalmos) in children

  • Hazy cornea in children

  • Unilateral watery eye

 Within days

  • Squint of recent onset

  • Suspected or previously diagnosed glaucoma

  • Double vision following recent injury might indicate orbital fracture

  • Leukocoria (white reflex from the pupil)

  • Squint at an age if not previously investigated by ophthalmologist

  • Visual loss in patients with systemic disease such as diabetes 

Non-urgent referral

  • Cataracts in adults

  • Refractive errors in teenage and adults

Longstanding blindness–first visit to health facility

Updated on, 2.11.2020


1. STG 

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