Gradual Loss of Vision

The four major causes of gradual blindness in the world are: cataract, onchocerciasis, vitamin A deficiency and trachoma. The latter three are very rare in the UK. Cataract occurs in 75% of over-65 s, but only 20% of 45- to 65-year-olds. Most cases of gradual loss of vision encountered in primary care arrive via the optician, often with a letter outlining the problem and suggesting referral to an ophthalmologist.

Published: 2nd August 2022 | Updated: 15th August 2022

Differential diagnosis

Common Diagnoses

  • Cataract
  • Chronic Glaucoma
  • Diabetic and Hypertensive Retinopathy
  • Senile Macular Degeneration
  • Gradual Inferior Retinal Detachment

Occasional Diagnoses

  • Choroidoretinitis
  • Optic Neuritis (in MS)
  • Paget’s Disease of the Skull
  • Retinitis Pigmentosa
  • Intraorbital or Intracranial Tumours

Rare Diagnoses

  • Syphilis
  • Cerebromacular Degeneration
  • Toxic Amblyopia (Tobacco, Methanol, Arsenic, Quinine, Carbon Bisulphide)
  • Choroidal Melanoma
  • Leber’s Hereditary Optic Atrophy

Ready reckoner

Key distinguishing features of the most common diagnoses

CataractGlaucomaRetinopathyMacular DegenerationRetinal Detachment
Unilateral Visual LossPossiblePossiblePossiblePossibleYes
Pigment at MaculaNoNoNoYesNo
Exudate + HaemorrhageNoNoYesYesNo
Fundus ObscuredYesNoPossibleNoNo
Disc Cupped >50%NoYesNoNoNo

Possible investigations

  • The only investigation the GP is likely to perform is a urinalysis and/or blood sugar or HbA1c for suspected diabetes. If glaucoma is a possibility, and the patient has not already seen the optician, then optician referral will provide information about fields and pressures. More obscure tests – such as posterior pole ultrasound and CT scan for retinal, or other, tumours; syphilis serology; skull X-ray for Paget’s disease; and neurological investigations for MS – are rarely required and are inevitably arranged in secondary care.

Top Tips

  • Opticians will tend to report cataracts in the elderly routinely. Referral for surgery is only required if the problem is significantly impairing the individual’s normal activities.
  • The presence of a cataract in relatively young patients is unusual and should prompt referral regardless of visual impairment – there may be a rare underlying metabolic cause.
  • Remember that significant glaucoma or other causes of visual loss may render the individual unfit to drive.
  • The elderly patient with a cataract whose vision is not improved considerably with the pinhole test probably has macular degeneration too, and so is unlikely to benefit much from cataract extraction.

Red Flags

  • It can be very difficult to establish in an elderly person whether the problem really has been gradual in onset or whether the history is more sudden; if in doubt, refer urgently as the cause may be acute and remediable.
  • Progressive early morning headache or proptosis with gradual loss of vision suggests a tumour. Refer urgently.
  • Gradual or recurrent visual loss or blurring with other intermittent neurological symptoms, especially in younger patients, suggests the possibility of MS.
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Website disclaimer

Pulse Reference is based on the best-selling book Symptom Sorter.

The experts behind Pulse Reference are Dr Keith Hopcroft who is the co-author of Symptom Sorter, a GP in Essex and Pulse’s editorial advisor and Dr Poppy Freeman, a GP in Camden and also a clinical advisor to Pulse.

This website is for clinical guidance only and cannot give definitive diagnostic information. Practitioners should work within the limits of their individual professional practice, seek guidance when necessary and refer appropriately.