ACCURACY OF OPTICAL BIOMETER AND A-SCAN FOR THE POWER CALCULATION OF INTRAOCULAR LENSES.
Abstract
Objective: The aim of this study is to investigate the accuracy of optical biometer and a-scan for the power calculation of intraocular lenses at SMS
Medical college ,jaipur .
Materials and Methods: We examined consecutive cataractous eyes with the optical biometer as well as with the acoustic biometry and
keratometry. In all eyes, the intraocular lens to be implanted was chosen by means of the SRK/T formula, based on the measurements conducted
with our standard method. The achieved postoperative refraction is obtained, at least 4 weeks after surgery, by the treating ophthalmologists. The
results were compared and analyzed statistically .
Results: We examined 86 out of which 36 female and 42 were male. Comparison of eye lengths as well as of the keratometric measurements
showed good correspondence between the obtained measurements by both methods, acoustic biometry yielding significantly (P < 0.001) different
axial lengths than the optical biometer, and the keratometry yielding significantly (P < 0.001) different mean corneal refraction power than the IOL
Master. The accuracy of the refraction obtained postoperatively compared to the preoperative aim was better with optical biometer compared to
acoustic method.
Conclusions: The predicted systemic differences in measurement results could be verified. Significant improvement in accuracy of our
postoperative refraction prediction was achieved using IOL master. The other advantages of the optical biometer are the substantial gain in time, as
well as the fact that performance of the measurements may be delegated. Only shortcoming was the use of optical biometer in mature cataract.
Keywords
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Olsen T. Sources of error in intraocular lens power calculation. J Cataract Refract Surg 1992;18:125-9.
[PUBMED]
Olsen T. The accuracy of ultrasonic determination of axial length in pseudophakic eyes. Acta Ophthalmol (Copenh) 1989;67:141-4.
[PUBMED]
Binkhorst RD. The accuracy of ultrasonic measurement of the axial length of the eye. Ophthalmic Surg 1981;12:363-5.
[PUBMED]
Schachar RA, Levy NS, Bonney RC. Accuracy of intraocular lens powers calculated from A-scan biometry with the Echo-Oculometer. Ophthalmic Surg 1980;11:856-8.
[PUBMED]
Olsen T. Theoretical approach to intraocular lens calculation using Gaussian optics. J Cataract Refract Surg 1987;13:141-5.
[PUBMED]
Packer M, Fine IH, Hoffman RS, Coffman PG, Brown LK. Immersion A-scan compared with partial coherence interferometry: outcomes analysis. J Cataract Refract Surg 2002;28:239-42.
Giers U, Epple C. Comparison of A-scan device accuracy. J Cataract Refract Surg 1990; 16:235-42.
Watson A, Armstrong R. Contact or immersion technique for axial length measurement? Aust N Z J Ophthalmol 1999;27:49-51.
Kutschan A, Wiegand W. Individual postoperative refraction after cataract surgery - a comparison of optical and acoustical biometry. Klin Monbl Augenheilkd 2004;221:743-8.
Huang D, Swanson EA, Lin CP, Schuman JS, Stinson WG, Chang W, et al. Optical coherence tomography. Science 1991;254:1178-81.
Huang D, Wang J, Lin C, Puliafito CA, Fujimoto JG. Micron resolution ranging of cornea anterior chamber by optical reflectometry. Lasers Surg Med 1991;11:419-25.
Fercher AF. Optical coherence tomography. J Biomed Opt 1996;1:157-73.
[PUBMED]
Fercher AF, Mengedoht K, Werner W. Eye length measurement by interferometry with partially coherent light. Opt Lett 1988;13:186-8.
[PUBMED]
Fercher AF, Hitzenberger CK, Juchem M. Measurement of intraocular optical distances using partially coherent laser light. J Mod Optics 1991;38:1327-33.
Hitzenberger CK. Optical measurement of the axial eye length by laser Doppler interferometry. Invest Ophthalmol Vis Sci 1991;32:616-24.
[PUBMED]
Hitzenberger CK, Drexler W, Dolezal C, Skorpik F, Juchem M, Fercher AF, et al. Measurement of the axial length of cataract eyes by laser Doppler interferometry. Invest Ophthalmol Vis Sci 1993;34:1886-93.
Eleftheriadis H. IOLMaster biometry: refractive results of 100 consecutive cases. Br J Ophthalmol 2003;87:960-3.
[PUBMED]
Kiss B, Findl O, Menapace R, Wirtitsch M, Drexler W, Hitzenberger CK, et al. Biometry cataractous eyes using partial coherence interferometry: Clinical feasibility study of a commercial prototype I. J Cataract Refract Surg 2002;28:224-9.
Leaming DV. Practice styles and preferences of ASCRS members-2000 survey. J Cataract Refract Surg 2001;27:948-55.
[PUBMED]
Rajan MS, Keilhorn I, Bell JA. Partial coherence laser interferometry vs. conventional ultrasound biometry in intraocular lens power calculations. Eye (Lond) 2002;16:552-6.
Shammas HJ. A comparison of immersion and contact techniques for axial length measurement. J Am Intraocul Implant Soc 1984;10:444-7.
[PUBMED]
Kiss B, Findl O, Menapace R, Wirtitsch M, Petternel V, Drexler W, et al. Refractive outcome of cataract surgery using partial coherence interferometry and ultrasound biometry: Clinical feasibility study of a commercial prototype II. J Cataract Refract Surg 2002;28:230-4.
Findl O, Drexler W, Menapace R, Heinzl H, Hitzenberger CK, Fercher AF. Improved prediction of intraocular lens power using partial coherence interferometry. J Cataract Refract Surg 2001;27:861-7.
Connors R 3rd, Boseman P 3rd, Olson RJ. Accuracy and reproducibility of biometry using partial coherence interferometry. J Cataract Refract Surg 2002;28:235-8.
Hitzenberger CK, Drexler W, Dolezal C, Skorpik F, Juchem M, Fercher AF, et al. Measurement of the axial length of cataract eyes by laser Doppler interferometry. Invest Ophthalmol Vis Sci 1993;34:1886-93.
Drexler W, Findl O, Menapace R, Rainer G, Vass C, Hitzenberger CK, et al. Partial coherence interferometry: A novel approach to biometry in cataract surgery. Am J Ophthalmol 1998;126:524-34.
Gantenbein C, Lang HM, Ruprecht KW, Georg T. First steps with the Zeiss IOLMaster: A comparison between acoustic contact biometry and non-contact optical biometry. Klin Monbl Augenheilkd 2003;220:309-14.
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