By ULY CLINIC

 

Visual problems

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Introduction

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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.

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Investigations

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• 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 

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Pin hole test

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• 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 

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Red Reflex Test

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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. 

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Significance of absent red reflex

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 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

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 If there are cataracts, one usually sees:

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

• Absence of red reflex in mature cataracts 

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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 

 

Referral: 

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

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 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 

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Non-urgent referral

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• Cataracts in adults

• Refractive errors in teenage and adults

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Longstanding blindness–first visit to health facility

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Updated on, 2.11.2020

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References

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1. STG