An official website of the United States government
The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before
sharing sensitive information, make sure you’re on a federal
government site.
The site is secure.
The https:// ensures that you are connecting to the
official website and that any information you provide is encrypted
and transmitted securely.
Prum BE Jr, Shields SR, Simmons RB, Echelman DA, Shields MB.Prum BE Jr, et al. Among authors: echelman da.Am J Ophthalmol. 1992 Nov 15;114(5):560-7. doi: 10.1016/s0002-9394(14)74483-6.Am J Ophthalmol. 1992.PMID: 1443016
Echelman DA, Stern RA, Shields SR, Simmons RB, Shields MB.Echelman DA, et al.Invest Ophthalmol Vis Sci. 1995 Feb;36(2):497-502.Invest Ophthalmol Vis Sci. 1995.PMID: 7843918