Name	Info	Provider	Link
	free resource	Elsevier Science	https://linkinghub.elsevier.com/retrieve/pii/S0042-6989(08)00296-4
Refractive Errors	free resource	MedlinePlus Health Information	https://medlineplus.gov/refractiveerrors.html
	subscription/membership/fee required	Ovid Technologies, Inc.	http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=linkout&SEARCH=18585401.ui
	free resource	PubMed Central	https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/18585401/
	free resource	Europe PubMed Central	https://europepmc.org/abstract/MED/18585401