Treatment of Macular Oedema in Patients with Hereditary Retinal Dystrophies by Applying the Micropulsed Subthreshold Laser

BACKGROUND:

Degenerative diseases of the visual system classified as rare and, in particular, those affecting the retina (known as Inherited retinal dystrophies, IRDs) cause very severe functional deficits. Their onset is in many cases particularly early with a consequent visual impact of extreme severity. They constitute a heterogeneous group from a clinical point of view, but in all of them the loss of photoreceptors causes progressive vision loss that can result in complete blindness.

These pathologies can be complicated by the presence of cataracts, epiretinal membrane and macular oedema (10-50%), resulting in a worsening of visual acuity. While surgical treatment is applicable for the first two complications, the treatment of macular oedema can make use of several options. Oral or topical diuretics (Acetazolamide) are still the first therapeutic approach and, if oedema persists despite treatment, intravitreal corticosteroid injection has been used in various reports. The injection of anti-Vascular Endothelial Growth Factor (VEGF) drugs and vitrectomy have also been proposed but with conflicting results. The use of topical non-steroidal drugs has been studied and proven to be valuable, although inferior to diuretic treatment in terms of visual recovery. The use of intravitreal corticosteroids is also not without possible further complications such as ocular hypertension and early onset of cataracts.

Despite some improvement in retinal oedema by taking the above-mentioned diuretics, relapses can be observed at the end of therapy, reason for taking longer periods (>12 weeks) of therapy. However, the same chronic continuation of diuretic therapy is not always desirable considering its possible adverse events such as tingling sensation, malaise, altered taste sensation and gastrointestinal disorders.

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