Biomaterial Database

Magnification and visual acuity in refractive surgery. 1993

R A Applegate, and H C Howland

Department of Ophthalmology, University of Texas Health Science Center at San Antonio.

In comparisons of retinal image size within the same eye before and after refractive surgery, a change in the plane of correction from the spectacle to the cornea induces a change in retinal magnification. Comparing retinal image size between eyes of different individuals, a change in the plane of correction as well as the type of ametropia (axial or refractive) interacts to change the retinal magnification. Consequently, comparing acuity before and after refractive surgery without considering the effects of retinal magnification can be misleading. Magnification effects can be large, accounting for a visual acuity increase of 1 line or more. Here we model the magnification induced by refractive surgery in various reference eyes and discuss implications in the context of current clinical trials.

UI	MeSH Term	Description	Entries
D008954	Models, Biological	Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.	Biological Model,Biological Models,Model, Biological,Models, Biologic,Biologic Model,Biologic Models,Model, Biologic
D009799	Ocular Physiological Phenomena	Processes and properties of the EYE as a whole or of any of its parts.	Ocular Physiologic Processes,Ocular Physiological Processes,Ocular Physiology,Eye Physiology,Ocular Physiologic Process,Ocular Physiological Concepts,Ocular Physiological Phenomenon,Ocular Physiological Process,Physiology of the Eye,Physiology, Ocular,Visual Physiology,Concept, Ocular Physiological,Concepts, Ocular Physiological,Ocular Physiological Concept,Phenomena, Ocular Physiological,Phenomenon, Ocular Physiological,Physiologic Process, Ocular,Physiologic Processes, Ocular,Physiological Concept, Ocular,Physiological Concepts, Ocular,Physiological Process, Ocular,Physiological Processes, Ocular,Physiology, Eye,Physiology, Visual,Process, Ocular Physiologic,Process, Ocular Physiological,Processes, Ocular Physiologic,Processes, Ocular Physiological
D012029	Refraction, Ocular	Refraction of LIGHT effected by the media of the EYE.	Ocular Refraction,Ocular Refractions,Refractions, Ocular
D012030	Refractive Errors	Deviations from the average or standard indices of refraction of the eye through its dioptric or refractive apparatus.	Ametropia,Refractive Disorders,Ametropias,Disorder, Refractive,Disorders, Refractive,Error, Refractive,Errors, Refractive,Refractive Disorder,Refractive Error
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D014792	Visual Acuity	Clarity or sharpness of OCULAR VISION or the ability of the eye to see fine details. Visual acuity depends on the functions of RETINA, neuronal transmission, and the interpretative ability of the brain. Normal visual acuity is expressed as 20/20 indicating that one can see at 20 feet what should normally be seen at that distance. Visual acuity can also be influenced by brightness, color, and contrast.	Acuities, Visual,Acuity, Visual,Visual Acuities
D054140	Refractive Surgical Procedures	Surgical procedures employed to correct REFRACTIVE ERRORS such as MYOPIA; HYPEROPIA; or ASTIGMATISM. These may involve altering the curvature of the CORNEA; removal or replacement of the CRYSTALLINE LENS; or modification of the SCLERA to change the axial length of the eye.	Keratorefractive Surgical Procedures,Refractive Surgery,Keratorefractive Surgical Procedure,Procedure, Keratorefractive Surgical,Procedure, Refractive Surgical,Procedures, Keratorefractive Surgical,Procedures, Refractive Surgical,Refractive Surgeries,Refractive Surgical Procedure,Surgeries, Refractive,Surgery, Refractive,Surgical Procedure, Keratorefractive,Surgical Procedure, Refractive,Surgical Procedures, Keratorefractive,Surgical Procedures, Refractive