Biomaterial Database

Effect of iris displacement on oblique astigmatism in aphakic eyes. 1991

M C Dunne, and D A Barnes, and G P Misson

Department of Vision Sciences, Aston University, Birmingham, United Kingdom.

Aphakic eyes possess considerably less oblique astigmatism than phakic eyes. The possibility that posterior iris displacement after lens extraction accounts for the observed reduction in oblique astigmatism is tested in this study. Oblique astigmatism was calculated for a phakic and an aphakic schematic eye. With no iris displacement little reduction of oblique astigmatism occurred contrary to experimental findings. However, introduction of varying levels of iris displacement reduced this aberration to values found experimentally. Posterior iris displacement (mean = 1.19 mm) was confirmed in vivo by pre- and postoperative anterior chamber pachometry in eight patients.

UI	MeSH Term	Description	Entries
D007498	Iris	The most anterior portion of the uveal layer, separating the anterior chamber from the posterior. It consists of two layers - the stroma and the pigmented epithelium. Color of the iris depends on the amount of melanin in the stroma on reflection from the pigmented epithelium.
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
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
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000328	Adult	A person having attained full growth or maturity. Adults are of 19 through 44 years of age. For a person between 19 and 24 years of age, YOUNG ADULT is available.	Adults
D000368	Aged	A person 65 years of age or older. For a person older than 79 years, AGED, 80 AND OVER is available.	Elderly
D000867	Anterior Chamber	The space in the eye, filled with aqueous humor, bounded anteriorly by the cornea and a small portion of the sclera and posteriorly by a small portion of the ciliary body, the iris, and that part of the crystalline lens which presents through the pupil. (Cline et al., Dictionary of Visual Science, 4th ed, p109)	Anterior Chambers,Chamber, Anterior,Chambers, Anterior
D001036	Aphakia, Postcataract	Absence of the crystalline lens resulting from cataract extraction.	Aphakic Eye, Postcataract,Aphakias, Postcataract,Postcataract Aphakia,Postcataract Aphakias,Postcataract Aphakic Eye,Postcataract Aphakic Eyes
D001251	Astigmatism	Unequal or irregular curvature of the CORNEA (Corneal astigmatism) and/or the EYE LENS (Lenticular astigmatism) resulting in REFRACTIVE ERROR.	Corneal Astigmatism,Hyperopic Astigmatism,Lenticular Astigmatism,Mixed Astigmatism,Myopic Astigmatism,Oblique Astigmatism,Astigmatism, Corneal,Astigmatism, Hyperopic,Astigmatism, Lenticular,Astigmatism, Mixed,Astigmatism, Myopic,Astigmatism, Oblique,Hyperopic Astigmatisms,Mixed Astigmatisms,Myopic Astigmatisms,Oblique Astigmatisms
D014795	Visual Pathways	Set of cell bodies and nerve fibers conducting impulses from the eyes to the cerebral cortex. It includes the RETINA; OPTIC NERVE; optic tract; and geniculocalcarine tract.	Pathway, Visual,Pathways, Visual,Visual Pathway