Table 2.

Comparison between SARS-CoV-2 and other human coronaviruses (HCoV)

HCoV	Global mortality rate	Genomic size	Target host receptor	Known ocular manifestations
SARS-CoV	9.6% to 11%	27.9 kb	ACE2	Nil known
MERS-CoV	37.1%	30.1 kb	DPP4	Nil known
SARS-CoV-2	2.9%	29.9 kb	ACE2	Conjunctival hyperaemia chemosis and secretions Epiphora Eyelid oedema Tarsal pseudomembranous Eye discomfort Follicular and haemorrhagic conjunctivitis Photophobia Superficial punctate keratitis Corneal epithelial defect Subepithelial infiltrates Pseudodendrite Dry eyes Asymptomatic retinal lesions Cotton wool spots Retinal microhaemorrhages

CoV, coronavirus; MERS, Middle East respiratory syndrome; SARS, severe acute respiratory syndrome.