Towards an Optimized Use of Ocular Corticosteroids: EURETINA Award Lecture 2017

Since their discovery, glucocorticoids (GCs) have been extensively used for the treatment of ocular diseases because of their anti-inflammatory, anti-edematous and angiostatic properties. Various GCs have been synthetized to optimize their beneficial anti-inflammatory effects and reduce their effects on sodium retention, identified as a mineralocorticoid effect, leading to a potency and specificity grading of the different GCs. However, the side effects, specificity and potency of GCs are highly tissue specific. Because the eye is a confined organ, local GC administration can reduce the systemic undesirable and severe side effects but does not protect from potential local toxicity and side effects, which are dose-dependent, influenced by the disease stage and by genetic and epigenetic susceptibility. GCs can potentially induce retinal cell death through non-classical pathways such as paraptosis and non-caspase-dependent apoptosis that could be undetectable when using classical toxicology tests. To reduce the risks of toxicity, therapeutic lower doses of GCs are desirable and can be achieved using optimized methods of administration such as transscleral iontophoresis or polymeric implants. In the retina, glucocorticoid receptor (GR) and mineralocorticoid receptor (MR) expression is regulated by disease conditions such as ocular inflammation. Activation of the MR pathway by its specific ligand, aldosterone, or by illicit GC occupation can cause retinal edema, subretinal fluid accumulation, and choroidal vasodilation and leakage, suggesting that central serous chorioretinopathy could benefit from MR antagonist. A better understanding of the MR/GR balance in the ocular tissue and the differential effects of their activation in the different ocular cells is still required to envisage an optimized use of GCs for the treatment of different ocular disease conditions.