Intraocular Lens Power Calculations: The Optimal Approach

Abstract

The differences were studied between retrospectively calculated emmetropizing intraocular lenses and lenses estimated from different methods and formulas, either with or without the use of ultrasonic biometry. A number of 201 eyes was involved. The results show that ultrasonic biometry is an indispensable tool for the prediction of the power of intraocular lenses, which would produce emmetropia. The best results were obtained when using biometry and the simple empirical SRK formula.

Status of toric intraocular lenses

“…A critical step in achieving the desired refractive outcome after cataract surgery is the precise preoperative measurement of axial length [14,15]. In fact, 54% of the errors in predicted refraction after IOL implantation are attributed to errors in axial length measurements [14], and an axial eye length measurement error of 100 mm results in a corresponding postoperative refractive error of 0.28 D [16].…”

Optical biometry of the anterior eye segment: Interexaminer and intraexaminer reliability of ACMaster

“…16 The IOLMaster has a high variability for ACD measurement, as described by Vogel and coauthors. 17 However, the IOLMaster uses a Scheimpflug photographic technique, not PCI, for measurement of ACD.…”

Key Developments for Partial Coherence Biometry and Optical Coherence Tomography in the Human Eye Made in Vienna

“…Although the axial resolution of this early PCI instrument was limited to approximately 100 lm (by the low bandwidth of the MMLD), the repeatability (SD) of the geometric eye length was much better: 19 lm on average in the cataract eyes, approximately an order of magnitude better than the 150 to 200 lm that had been reported in literature for ultrasound measurements. 15,16 In conjunction with the higher convenience for the patient (no contact or anesthesia needed), this provided the basis for the commercial success of this technology for ocular biometry in cataract surgery (e.g., Carl Zeiss IOL Master; Carl Zeiss Meditec, Jena, Germany), where PCI nearly completely replaced ultrasound-based measurements.…”