Case Studies

Case 2: Postpartum blurred vision

A 25-year-old woman had poorly controlled type 1 diabetes throughout her teenage years, as she believed insulin made her put on weight. She was referred from the Obstetrics team, as her vision has been ‘blurry’ since giving birth. You diagnose maculopathy.

• 1. Name the clinical classifications of diabetic maculopathy.

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  Correct answer: Diabetic maculopathy can be classified as:

  • Thickening of the retina within 500 µm from the fovea
  • Hard exudates and adjacent thickening of the retina within 500  µm from the fovea
  • Area of retinal thickening one disc size (or larger), part of which is one disc diameter from the fovea.

• 2. How is the pathology in maculopathy different from that of retinopathy?

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  Correct answer: Retinopathy occurs due to leaky vessels and progressive ischaemia: maculopathy has the same pathogenesis. However, the changes are within the macula in the latter (this is the only difference!).

• 3. How might diabetic retinopathy changes be accelerated?

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  Correct answer: Diabetic retinopathy changes can be accelerated by:

  • Pregnancy
  • High HbA1c
  • Nephropathy
  • Obesity
  • High cholesterol
  • High blood pressure.

  Rapid improvement in HbA1c reduces nutrients to the retina: this exacerbates ischaemia and worsens retinopathy. Hence it requires a multidisciplinary team effort to bring down the HbA1c slowly and safely in a controlled fashion.
  Diabetic eye disease can worsen for up to 12–18 months following improved glycaemic control.

Her VA was 6/9, and FFA revealed a non-ischaemic, exudative maculopathy with focal leakage. You discuss the option of laser, and she is keen to go ahead. She is happy that this will improve her vision, and subsequently she can relax on her diabetic control.

• 4. Do you agree that she can relax her diabetic control following laser treatment? Please give reasons for your answer.

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  Correct answer: No matter what treatment is given to the eye, retinopathy will continue to be present if the diabetic control is poor: under no circumstance can any patient relax on the diabetic control.
  The ETDRS study showed that macular laser reduced the risk of visual loss in patients with clinically significant macular oedema (CSMO): however, only 3% of patients achieved visual improvement. Hence, laser alone will not improve vision; good control is key.

• 5. What HbA1c (glycosylated haemoglobin) level should she be aiming for gradually?

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  Correct answer: Gradually bring down the HbA1C to below 7.2%.

Despite three lots of focal grid laser, her VA reduces down to 6/18, and she has significant distortion. She has heard of eye injections that her grandmother had recently and wanted to explore whether this would help her vision.

• 6. What injections might these be? Do you think these would be useful in the management of diabetic maculopathy?

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  These injections are ranibizumab or bevacizumab. Multiple clinical trials have shown the benefit of ranibizumab directly over macular laser in treating CSMO. These include the DRCR.net, RESOLVE, RESTORE and READ-2 trials. These trials quote between 6 and 15-letter improvement after ranibizumab treatment.

• 7. She has micro-albuminuria, normal blood pressure and a normal lipid profile. Is there a role for statin and fibrate? For any anti-hypertensive agents?

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  An angiotensin-converting enzyme inhibitor and statin +/− fenofibrate (as per the FIELD and ACCORD studies) as indicated.