Kenneth J. Hoffer
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View article: IOL Power Calculation by Ray Tracing in Eyes with Previous Radial Keratotomy
IOL Power Calculation by Ray Tracing in Eyes with Previous Radial Keratotomy Open
Background/Objectives: To evaluate the accuracy of intraocular lens (IOL) power calculation by ray tracing in eyes with previous radial keratotomy (RK). Methods: A consecutive series of patients with previous RK was retrospectively analyze…
View article: Comparison of intraocular lens formula accuracy for eyes with prior scleral buckle surgery
Comparison of intraocular lens formula accuracy for eyes with prior scleral buckle surgery Open
Purpose: To compare intraocular lens (IOL) formula prediction accuracy for patients with previous scleral buckling surgery. Setting: Single academic center in Los Angeles, California. Design: Retrospective study. Methods: Patients who had …
View article: Data Analysis in IOL Power Calculations
Data Analysis in IOL Power Calculations Open
This chapters describe the guidelines for studies on IOL power calculation. Information about sample size, timing of postoperative refraction measurement, constant optimization, prediction error and standard deviation calculation, predicti…
View article: Online IOL Power Calculators
Online IOL Power Calculators Open
This chapter aims to provide readers with the latest online intraocular (IOL) power calculators developed by individual ophthalmologists and researchers to improve the refractive outcomes of cataract surgery. Means to access them and utili…
View article: Correction to: Intraocular Lens Calculations
Correction to: Intraocular Lens Calculations Open
View article: Hoffer Formulas
Hoffer Formulas Open
This chapter describes the evolution of the first IOL power calculation formula developed in the United States, through its upgrading over the years as new information developed regarding the biometric relationship involved in calculating …
View article: The History of the IOL Power Club: 2005–2025
The History of the IOL Power Club: 2005–2025 Open
The IOL Power Club began at the 2024 ASCRS meeting because of an accidental meeting of 4 IOL power formula autthors (Aramberri, Haigis, Hoffer & Olsen). This led to them getting together, along with inviting 2 others (Norrby & Shammas), fo…
View article: IOL Power Calculation After Corneal Refractive Surgery
IOL Power Calculation After Corneal Refractive Surgery Open
Intraocular lens (IOL) power calculation is affected by the effect of any previous corneal refractive surgery. In this chapter, an extensive analysis of the different sources of error and the correspondent solutions is performed. Corneal s…
View article: American History of IOL Power Calculation
American History of IOL Power Calculation Open
The history of ultrasound axial length measurement and formula development for IOL power calculation in America are described beginning with the initial trials in April 1974, and through the trials and tribulations the author experienced i…
View article: The Haigis Formula
The Haigis Formula Open
The Haigis formula, like other optical formulas, is based on thin lens optics. However, while all other formulas use only one constant (like the ACD constant, the A-constant, or the surgeon factor) for a given IOL, the Haigis formula uses …
View article: Differences Between Keratometry and Total Keratometry Measurements in a Large Dataset Obtained With a Modern Swept Source Optical Coherence Tomography Biometer
Differences Between Keratometry and Total Keratometry Measurements in a Large Dataset Obtained With a Modern Swept Source Optical Coherence Tomography Biometer Open
This large-scale study underscores the similarity between mean K and TK values in healthy eyes, with rare clinical implications for IOL power calculation. Noteworthy differences were observed in astigmatism values between K and TK. Future …
View article: Accuracy of Haigis Formula Using Total Keratometry for IOL Power Calculation in Eyes with Previous Myopic and Hyperopic LASIK and PRK
Accuracy of Haigis Formula Using Total Keratometry for IOL Power Calculation in Eyes with Previous Myopic and Hyperopic LASIK and PRK Open
Background: this retrospective study aimed to analyze the results of the combination of the Haigis formula and total keratometry (TK) in calculating the IOL power in eyes with previous corneal refractive surgery. Methods: the TK value prov…
View article: Accuracy of Haigis Formula Using Total Keratometry for IOL Power Calculation in Eyes with Previous Myopic and Hyperopic LASIK
Accuracy of Haigis Formula Using Total Keratometry for IOL Power Calculation in Eyes with Previous Myopic and Hyperopic LASIK Open
Background: this retrospective study aimed to analyze the results of the combination of the Haigis formula and Total Keratometry (TK) to calculate the IOL power in eyes with previous corneal refractive surgery. Methods: The TK value provid…
View article: <scp>Split‐Window OCT</scp> biometry in pseudophakic eyes
<span>Split‐Window OCT</span> biometry in pseudophakic eyes Open
Purpose To determine the utility of Split‐Window optical coherence tomography OCT (SW‐OCT) biometry in measuring ocular axial dimensions as well as imaging the intraocular lens (IOL) and posterior capsule in pseudophakic eyes. Methods Sixt…
View article: Repeatability of automated measurements by a new anterior segment optical coherence tomographer and biometer and agreement with standard devices
Repeatability of automated measurements by a new anterior segment optical coherence tomographer and biometer and agreement with standard devices Open
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View article: Repeatability of total Keratometry and standard Keratometry by the IOLMaster 700 and comparison to total corneal astigmatism by Scheimpflug imaging
Repeatability of total Keratometry and standard Keratometry by the IOLMaster 700 and comparison to total corneal astigmatism by Scheimpflug imaging Open
View article: Recent developments in intraocular lens power calculation methods—update 2020
Recent developments in intraocular lens power calculation methods—update 2020 Open
For many decades only a few formulas have been available to calculate the intraocular lens (IOL) power for patients undergoing cataract surgery: the Haigis, Hoffer Q, Holladay 1 and 2 and SRK/T. In recent years, several new formulas for IO…
View article: Intraocular lens power calculation in eyes with previous corneal refractive surgery
Intraocular lens power calculation in eyes with previous corneal refractive surgery Open
IOL power calculation after myopic corneal refractive surgery can be calculated with a variety of methods that lead to relatively accurate outcomes, with 60 to 70% of eyes showing a prediction error within 0.50 diopters.
View article: Repeatability of automatic measurements by a new anterior segment optical coherence tomographer combined with Placido topography and agreement with 2 Scheimpflug cameras
Repeatability of automatic measurements by a new anterior segment optical coherence tomographer combined with Placido topography and agreement with 2 Scheimpflug cameras Open
The high repeatability of automatic measurements by the new AS-OCT device supports its use in clinical practice.
View article: Ocular biometric measurements in cataract surgery candidates in Portugal
Ocular biometric measurements in cataract surgery candidates in Portugal Open
These data represent normative biometric values for the Portuguese population. The greatest predictor of ocular biometrics was gender. There was no significant correlation between age and AL, ACD, or Km. These results may be relevant in th…
View article: Correction: Accuracy of optical biometry combined with Placido disc corneal topography for intraocular lens power calculation
Correction: Accuracy of optical biometry combined with Placido disc corneal topography for intraocular lens power calculation Open
[This corrects the article DOI: 10.1371/journal.pone.0172634.].
View article: Accuracy of optical biometry combined with Placido disc corneal topography for intraocular lens power calculation
Accuracy of optical biometry combined with Placido disc corneal topography for intraocular lens power calculation Open
[This corrects the article DOI: 10.1371/journal.pone.0172634.].