retinal detachment: visual impairment resulting from the retina becoming separated from the choroid in the back of the eye; treated by photocoagulation
visual impairment: impairment of the sense of sight
tree fern: any of numerous usually tropical ferns having a thick woody stem or caudex and a crown of large fronds; found especially in Australia and New Zealand; chiefly of the families Cyatheaceae and Marattiaceae but some from Polypodiaceae