Cases

Case 1: An elderly patient with acute visual loss

An 88-year-old man was referred from the optician’s with suspected macular 'spots'. His past medical history (PMH) included poorly controlled chronic obstructive pulmonary disease (COPD), pubic rami fracture, previous cerebrovascular accident (CVA), hypothyroidism and anterior blepharitis. In clinic, you diagnose hard drusen without any distortion.

• 1. What in the PMH gives a clue for a recognised risk factor for macular degeneration?

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  Correct answer: This man has COPD, so one must enquire as to whether active smoking caused this and, if so, if he is still a smoker. The following have been linked as risk factors for developing macular degeneration:

  • - Smoking (main modifiable risk factor)
  • - Age
  • - Gender
  • - Genetic (including variants in the gene encoding complement factor H).

• 2. How soon should this patient be seen in clinic?

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  Correct answer: Without any symptoms of distortion or virtual loss, this patient can be seen routinely in clinic. If distortion is present, we would like to see these patients within 48 hours.

• 3. How should he be managed?

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  Correct answer: This patient seems to have the dry form of the disease. The best way to manage this patient is as follows:

  • - Do an optical coherence tomography (OCT) examination as a baseline for future consultations and to determine if there is any OCT evidence of retinal fluid indicative of wet AMD.
  • - Advise him to stop smoking.
  • - Give advice for vitamin supplements.
  • - Discharge him from the clinic.
  • - Give him an Amsler grid. Ask him to test each eye (with any refractive correction), one at a time, on a regular basis. If he notices distortion, he should come to casualty for further assessment.

Eighteen months later, he acutely loses vision in his left eye. Dilated fundoscopy reveals a mottled and elevated appearance of the macula. You suspect wet age-related macular degeneration (ARMD).

• 4. What investigation should you request to confirm your diagnosis?

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  Correct answer: Ask for a fundus fluorescein angiography (FFA), looking primarily for:

  • - Early, lacy hyperfluorescence (classic choroidal neovascular membrane (CNVM))
  • - Late, stippled leakage (occult CNVM).

• 5. What is a differential diagnosis of a choroidal neovascular membrane from this investigation?

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  Correct answer: This would include retinal angiomatous proliferation (RAP). Think of this as the opposite to CNVMs, whereby vessels from the retina grow down into the subretinal space and communicate with choroidal vessels. These are best distinguished with indocyanine green angiography (ICG).

His visual acuity (VA) is 6/36, and a diagnosis of classic wet ARMD is made. There is a discussion in the clinic as to the best management regime, either photodynamic therapy or intra-vitreal anti-VEGF (vascular endothelial growth factor) injections.

• 6. Can you quote a study to help guide best management?

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  Correct answer: Quote the ANCHOR trial, where patients with classic CNVM were randomised to either monthly ranibizumab or photodynamic therapy: at 12 months, the percentage gaining 15 letters was 40% versus 6%.