title: Calculating the surgically induced refractive change following ocular surgery.
abstract: Calculating the surgically induced refractive change following ocular surgery is important for evaluating the results of keratore-fractive procedures, smaller incisions and various wound closures for cataract surgery, and the effect of suturing techniques and suture removal following corneal transplant surgery. We present a ten-step method of calculating the spherical- and cylindrical-induced refractive change in a manner suitable for a programmable calculator or personal computer. Several applications are given including (1) adding the overrefraction to the spectacle correction, (2) determining the surgically induced refractive change from the preoperative and postoperative refractions, (3) determining the surgically induced refractive change from the K-readings, (4) rotating axes, (5) determining the power at meridians oblique to the principal meridians of a spherocylinder, (6) determining the coupling ratio, and (7) averaging axes. Standard methods for calculating and reporting aggregate results are also given.
authors.affiliation: Hermann Eye Center, University of Texas Medical School, Houston 77030.
authors.forename: J T
authors.initials: JT
authors.lastname: Holladay
authors.forename: T V
authors.initials: TV
authors.lastname: Cravy
authors.forename: D D
authors.initials: DD
authors.lastname: Koch
mesh_terms: D001251:Astigmatism / Q000175:diagnosis* / Q000209:etiology; D002387:Cataract Extraction / Q000009:adverse effects*; D003315:Cornea / Q000473:pathology / Q000601:surgery*; D016039:Corneal Transplantation / Q000009:adverse effects*; D003936:Diagnosis, Computer-Assisted; D006801:Humans; D008433:Mathematics; D011183:Postoperative Complications; D012029:Refraction, Ocular