Refractive predictability of partial coherence interferometry and factors that can affect it
| Autor: | Joohyun Choi, Sangkyung Choi, Seung Mo Kim |
|---|---|
| Rok vydání: | 2008 |
| Předmět: |
Male
Refractive error Visual acuity Refractive predictability genetic structures Light medicine.medical_treatment Prediction error Visual Acuity Intraocular lens Refraction Ocular Lens Implantation Intraocular medicine Humans IOL master Dioptre Aged Retrospective Studies Aged 80 and over Lenses Intraocular Phacoemulsification business.industry food and beverages Reproducibility of Results General Medicine Cataract surgery medicine.disease Refractive Errors Refraction eye diseases Interferometry Fixation (visual) Optometry Female Original Article sense organs medicine.symptom business Partial coherence interferometry |
| Zdroj: | Korean Journal of Ophthalmology : KJO |
| ISSN: | 2092-9382 |
| Popis: | Since Harold Ridley implanted the first intraocular lens (IOL) into a blind eye and found a surprising refractive error of -20 diopters (D) in 1949, there have been many efforts made toward the precise prediction of refractive status following cataract surgery. With improvements in surgical techniques and innovations in the materials and designs of IOLs, patient expectations have also steadily increased significantly. Accuracy in the prediction of postoperative refraction is highly requested after the introduction of multifocal IOLs. Accurate refractive prediction requires good measurements of the corneal power and the axial length (AL), use of a suitable IOL calculation formula to predict the postoperative anterior chamber depth (ACD), an IOL with accurate power, and an uneventful surgery without complications. However, among these variables, it has been repeatedly emphasized that biometry is the most critical factor in obtaining the expected final refractive result.1-3 For the AL measurement, the ultrasound (US) method had been the gold standard. However, its accuracy seems to vary among operators and even among US devices.4,5 Recently, a new device for biometry, using the principle of partial coherence interferometry (PCI) has been developed. Until today, the IOL Master® (Carl Zeiss, Germany) is the only commercially available PCI device for ocular biometry. It has been well demonstrated that the IOL Master® is operator independent,5-7 highly precise, accurate, reproducible,2,6,8-11 efficient,12 and comfortable for patients.2,11,13 The IOL Master® also has an advantage over the US in that it requires no contact with the eyes, thus minimizing the risk of corneal injury and infection.5,6 It has been proposed that the IOL Master® is more likely to measure the true visual axis when the patient can maintain proper fixation during the examination.14 On the contrary, the ability to maintain proper fixation during repeated measurements is likely to affect the accuracy and reproducibility of measurements. Factors that might affect fixation include old age, dense opacities in the ocular media, poor preoperative visual acuity, and preoperative refraction. Dense opacities in the visual axis may also cause scattering of light used for PCI biometry.15 A low signal-to-noise ratio (SNR) may indicate that the quality of the measurement is less than optimal.16,17 Although PCI biometry has become more widely used, there are only a few reports regarding the degree to which the prediction of final refraction is actually affected by the various factors listed above.15,18-20 The principal purpose of this study is to evaluate the refractive predictability of the IOL Master® for phacoemulsification cataract surgery with posterior chamber IOL implantation and to examine the effects of multiple factors on the accuracy of the refractive predictability. |
| Databáze: | OpenAIRE |
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