EYE-REVISE

​Background

• Age-related macular degeneration (AMD) is the most common cause of blindness in adults over 50 in industrialised nations

• Types of AMD

  • dry / atrophic​

  • wet / neovascular / exudative

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Symptoms​

• Causes central scotomas (loss of central part of vision) 

• vision distortion​​​

• gradual decline in central part of visual field

• can be sudden if retinal haemorrhages occur

• peripheral vision usually maintained

• patients describe loss of ability to read, distinguish and recognise faces, see bus numbers

• 40-50% risk of developing disease in the contralateral eye once diagnosis in one eye is made

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Risk factors

• older age​

• smoking

• positive family history

• genetic - complement factor H

• sunlight 

• cardiovascular - raised BP, hypercholesterolaemia, obesity

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Dry AMD

• more common form​

• develop drusen over the macular, small yellow flecks

  • may be 'soft' or 'hard' drusen​

  • soft drusen are paler in colour, large and poorly defined edges

  • hard drusen - round and clearly defined yellow spots​

  • soft drusen evolve to macular degeneration

  • hard drusen can evolve to soft drusen which can develop into dry or wet AMD

 

Investigations​​

• Fundus fluorescein angiography (FFA) - can show formation of new vessels in wet AMD

• Optical coherence tomography (OCT) - 

• Amsler grid - printed grid given to patients to use to monitor for any new vision changes or distortion 

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Wet AMD

• less common for​m 

• causes more severe and dramatic deterioration in vision

• involves choroidal neovascularisation (CNV) in which new vessels grow on the retina which are prone to bleeding

• leads to scarring of lesions on the macula and resultant loss of central vision 

• central scarring lesions referred to as disciform scars

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Treatment - dry AMD

• no treatment in many cases​

• magnifiers and other low vision aids 

• high dose zinc and vitamins C, E, beta-carotene helps prevent disease advancing in patients with unilateral AMD

• sight impairment registration 

• social support e.g. occupational therapy input

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Treatment - wet AMD

• non-selective anti-VEGF-A agents: ranibizumab (Lucentis), bevacizumab (Avastin) ​

• anti-VEGF-A and anti-VEGF-B agent: aflibercept (Eylea)

• given as intravitreal injections, inhibit VEGF which are growth factors promoting new blood vessel growth

• response to treatment monitored with optical coherence tomography (OCT)

• risks of intravitreal injections = endophthalmitis, intraocular haemorrhage, retinal detachment

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References

•  Denniston, A. K. O. and Murray, P. I. (eds) (2018) Oxford handbook of ophthalmology. 4th edn. London, England: Oxford University Press (Oxford Medical Handbooks). doi: 10.1093/med/9780198804550.001.0001.

• ​​James, B., Bron, A. J. and Parulekar, M. V. (2016) Lecture Notes Ophthalmology. 12th edn. Nashville, TN: John Wiley & Sons (Lecture Notes)

• Salmon, J. F. (2019) Kanski’s clinical ophthalmology. 9th edn. London, England: Elsevier Health Sciences.​

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