Outline
- Purpose of Review
- Recent Findings
- Summary
- Keywords
- Introduction
- Axial Length Measurement
- Ultrasound Biometry
- Optical Biometry
- Anterior Chamber Depth Measurement
- Corneal Refractive Power
- Intraocular Lens Power Calculation
- Conclusion
- References and Recommended Reading
رئوس مطالب
- هدف بررسی
- یافتههای اخیر
- چکیده
- کلیدواژه ها
- مقدمه
- اندازهگیری طول محوری
- بیومتری فراصوت
- بیومتری اپتیکی
- اندازهگیری عمق حفره قدامی
- قدرت انکساری قرنیه
- محاسبه قدرت لنز داخل چشمی
- نتیجهگیری
Abstract
Purpose of review
Heightened patient expectations for precise postoperative refractive results have spurred the continued improvements in biometry and intraocular lens calculations. In order to meet these expectations, attention to proper patient selection, accurate keratometry and biometry, and appropriate intraocular lens power formula selection with optimized lens constants are required. The article reviews recent studies and advances in the field of biometry and intraocular lens power calculations.
Recent findings
Several noncontact optical-based devices compare favorably, if not superiorly, to older ultrasonic biometric and keratometric techniques. With additional improvements in the internal acquisition algorithm, the new IOL Master software version 5 upgrade should lessen operator variability and further enhance signal acquisition. The modern Haigis-L and Holladay 2 formulas more accurately determine the position and the shape of the intraocular lens power prediction curve.
Summary
Postoperative refractive results depend on the precision of multiple factors and measurements. The element with the highest variability and inaccuracy is, ultimately, going to determine the outcome. By understanding the advantages and limitations of the current technology, it is possible to consistently achieve highly accurate results.
Keywords: biometry - cataract surgery - intraocular lens calculationConclusions
With increasing patient expectations, the first step to obtain an accurate IOL power calculation is to be able to identify the patient’s visual goals, especially if they have specific vocational or avocational needs. Using today’s technology, it is possible to consistently have postoperative refractive outcomes within 0.25 D of the targeted refraction. In order to achieve these results, attention to proper patient selection, accurate keratometry and biometry, appropriate IOL power formula selection with optimized lens constant, and proper configuration of the capsulorhexis are required. Ultimately, the part with the highest variability and inaccuracy is going to determine the outcome. The accuracy of IOL biometry can be improved by implementing the following: minimizing variability and improving consistency by assigning a single properly calibrated instrument and experienced technician for the work-up, repeating and verifying measurements by a second person when necessary, using the IOL Master or immersion biometry rather than an applanation technique, using one of the newer IOL power calculation formulas and personalizing the lens constants for each formula, tracking your refractive outcomes, and optimizing your surgical technique by making the capsulorhexis round, centered and slightly smaller than the lens optic can all help to optimize your postoperative outcomes. By understanding the advantages and limitations of the current technology and following these guidelines, it is possible to consistently achieve highly accurate results.