FIELD: medicine.
SUBSTANCE: invention relates to medicine, namely ophthalmosurgery. To determine the optical strength of the intraocular lens (IOL) in patients with cataracts after radial keratotomy, a radius of the anterior surface bending of the cornea is measured in the central optical zone with a diameter of 1.5÷3.0 mm (RP, mm) and eye length (L, mm). Optical strength of the IOL (Piol, dptr) is calculated by the formula:
where Rz (mm) – radius of posterior surface bending of the cornea: Rz=2.055×RP+0.025×L-0.016×RP×L-7.234; C (mm) – position of the second main focal point of the combined optical system "cornea – anterior chamber – IOL": C =-0.055×Rz2+1.189×Rz-4.055, N (mm) – the effective position of the IOL, calculated by the formula:
where A (conditional units) – A-constant IOL; W (mm) – corneal diameter:
.
EFFECT: method makes it possible to increase the accuracy of determining the optical strength of the IOL after radial keratotomy, by measuring the minimum possible number of eye parameters, no need for refractive data preceding radial keratotomy and taking into account the individual parameters of the eye optical system, calculated from empirically derived formulas.
1 cl, 2 dwg, 2 tbl
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Authors
Dates
2018-02-13—Published
2017-02-09—Filed