Recommendations to standardise definitions for age-related macular degeneration (AMD) and its subtypes have been made by an international working group of retina specialists, ocular pathologists and imaging experts.

The group, called the Consensus on Neovascular AMD Nomenclature (CONAN), collaborated over three years on definitions of AMD and its sub-classifications, beyond the Beckman Classification proposed in 2013.

CONAN said it deems standardisation necessary due to advances in retinal imaging revealing other forms of AMD and nuances in pathology that previous definitions did not reflect.

In its report, published in Modern Retina, CONAN defines AMD as, “A process by which the structure and function of the macula deteriorates over time in association with distinguishing signs and symptoms that typically become evident clinically beyond 50 years of age and do not seem to be secondary to other processes such as pathologic myopia, central serous chorioretinopathy, monogenetic inherited retinal disease, chorioretinal uveitic syndromes or infections, or trauma.”

While it defined macular neovascularization (MNV) as, “an invasion by vascular and associated tissues into the outer retina, subretinal space, or sub-retinal pigment epithelial (RPE) space in varying combinations,” with three subtypes.