title: Intraocular lens calculation. An evaluation of Binkhorst and SRK estimates in 100 consecutive cataract extractions with 3M type 78 anterior chamber lens implantation.
abstract: Intraocular lens power prediction and final astigmatism were evaluated in 100 consecutive cataract patients (age 57-92 years, mainly with intracapsular extraction) 4-13 months after insertion of a 3M type 78 anterior chamber lens. The analysis was based on refractive recordings from the referring ophthalmologists who took care of post-operative controls. Ninety-two patients were accepted for the study. A Sonometrics DBR 400 ultrasound equipment and a Haag-Streit keratometer had been used for measuring eye length and corneal power, the Binkhorst programme and SRK formula for selecting IOL power, resulting in an IOL range of +12 to +23 D. Mainly, low myopia was intended. Nearly 50% fell within 0.5 D from predicted value; 90% were within +/- 1.5 D, by both calculating methods. SRK predictions appeared unaffected by eye size, while axial length (x) significantly influenced Binkhorst prediction (y): y = 8.08-0.35x (r = -0.40), the deviation being most marked in very short eyes. For eyes of midsize the two methods did not differ. Regarding astigmatism, 3 patients ended with values above 3D. In 83% it was less than 2D. Eighty per cent obtained a visual acuity of 0.5 or better. All things considered we feel that the calculation procedure should be standard when performing cataract surgery with IOL implantation.
authors.affiliation: Department of Ophthalmology, Frederiksborg County Hospital, Hillerød, Denmark.
authors.forename: H C
authors.initials: HC
authors.lastname: Fledelius
authors.forename: P H
authors.initials: PH
authors.lastname: Alsbirk
authors.forename: E
authors.initials: E
authors.lastname: Goldschmidt
mesh_terms: D000368:Aged; D000867:Anterior Chamber; D003315:Cornea / Q000033:anatomy & histology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007910:Lenses, Intraocular; D008297:Male; D008875:Middle Aged; D014463:Ultrasonography; D014792:Visual Acuity