Biomaterial Database

[IOL power determination using regression formula of lens location]. 1993

T Kashiwagi

Kashiwagi Eye Clinic, Sakai-city, Japan.

Postoperative lens location was expressed as a linear regression formula of axial length and corneal curvature. Using the formula, the IOL power of a convexplano, biconvex, and planoconvex lens was calculated by Ray Tracing Error Correction (RTEC). The calculated power of a convexplano lens coincides with Sanders, Retzlaff, Kraff (SRK) II in axial length less than 28 mm and corneal curvature between 7 to 9 mm. Varying regression coefficients changes lens power continuously and simulates the theoretical formulas SRK II and SRK. RTEC predicted that formula SRK II is valid only for a convexplano lens and needs correction in a biconvex or planconvex lens and in corneal curvature less than 7.0 mm. IOL power determination requires a learning process based on the postoperative refraction. The difference of learning between SRK and RTEC is also discussed.

UI	MeSH Term	Description	Entries
D007910	Lenses, Intraocular	Artificial implanted lenses.	Implantable Contact Lens,Lens, Intraocular,Contact Lens, Implantable,Intraocular Lens,Intraocular Lenses,Lens, Implantable Contact
D009907	Optometry	The professional practice of primary eye and vision care that includes the measurement of visual refractive power and the correction of visual defects with lenses or glasses.	Optometries
D011184	Postoperative Period	The period following a surgical operation.	Period, Postoperative,Periods, Postoperative,Postoperative Periods
D012044	Regression Analysis	Procedures for finding the mathematical function which best describes the relationship between a dependent variable and one or more independent variables. In linear regression (see LINEAR MODELS) the relationship is constrained to be a straight line and LEAST-SQUARES ANALYSIS is used to determine the best fit. In logistic regression (see LOGISTIC MODELS) the dependent variable is qualitative rather than continuously variable and LIKELIHOOD FUNCTIONS are used to find the best relationship. In multiple regression, the dependent variable is considered to depend on more than a single independent variable.	Regression Diagnostics,Statistical Regression,Analysis, Regression,Analyses, Regression,Diagnostics, Regression,Regression Analyses,Regression, Statistical,Regressions, Statistical,Statistical Regressions
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man