Abstract
Biometry has become one of the most important steps in modern cataract surgery and, according to the Royal College of Ophthalmologists Cataract Surgery Guidelines, what matters most is achieving excellent results. This paper is aimed at the NHS cataract surgeon and intends to be a critical review of the recent literature on biometry for cataract surgery, summarising the evidence for current best practice standards and available practical strategies for improving outcomes for patients. With modern optical biometry for the majority of patients, informed formula choice and intraocular lens (IOL) constant optimisation outcomes of more than 90% within ±1 D and more than 60% within ±0.5 D of target are achievable. There are a number of strategies available to surgeons wishing to exceed these outcomes, the most promising of which are the use of strict-tolerance IOLs and second eye prediction refinement.
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References
Ridley H . Intraocular acrylic lenses. A recent development in the surgery of cataract. Br J Ophthalmol 1952; 36: 113–122.
Apple DJ, Sims J . Harold Ridley and the invention of the intraocular lens. Surv Ophthalmol 1996; 40 (4): 279–292.
Hoffer KJ . Pre-operative cataract evaluation: intraocular lens power calculation. Int Ophth Clin 1982; 22: 37–75.
Olsen T . Pre- and postoperative refraction after cataract extraction with implantation of standard power IOL. Br J Ophthalmol 1988; 72: 231–235.
Hillman JS . Intraocular lens power calculation for emmetropia: a clinical study. Br J Ophthalmol 1982; 66: 53–56.
Minassian DC, Rosen P, Dart JK, Reidy A, Desai P, Sidhu M et al. Extracapsular cataract extraction compared with small incision surgery by phacoemulsification: a randomised trial. Br J Ophthalmol 2001; 85: 822–829.
Mylonas G, Sacu S, Buehl W, Ritter M, Georgopoulos M, Schmidt-Erfurth U . Performance of three biometry devices in patients with different grades of age-related cataract. Acta Ophthalmol 2011; 89: e237–e241.
Lee AC, Qazi MA, Pepose JS . Biometry and intraocular lens power calculation. Curr Opin Ophthalmol 2008; 19: 13–17.
Sahin A, Hamrah P . Clinically relevant biometry. Curr Opin Ophthalmol 2012; 23: 47–53.
Gale RP, Saldana M, Johnston RL, Zuberbuhler B, McKibbin M . Benchmark standards for refractive outcomes after NHS cataract surgery. Eye 2006; 23: 149–152.
The Royal College of Ophthalmologists Cataract Surgery Guidelines. [Online] 2010. Available from http://www.rcophth.ac.uk/core/core_picker/download.asp?id=544&filetitle=Cataract+Surgery+Guidelines+2010. (Accessed 21 September 2013).
Norrby S . Sources of error in intraocular lens power calculation. J Cataract Refract Surg 2008; 34: 368–376.
Olsen T . Use of fellow eye data in the calculation of intraocular lens power for the second eye. Ophthalmology 2011; 118: 1710–1715.
Hill W, Angeles R, Otani T . Evaluation of a new IOLMaster algorithm to measure axial length. J Cataract Refract Surg 2008; 34: 920–924.
Gale RP, Saha N, Johnston RL . National biometry audit II. Eye 2006; 20: 25–28.
Nemeth G, Nagy A, Berta A, Modis L Jr . Comparison of intraocular lens power prediction using immersion ultrasound and optical biometry with and without formula optimization. Graefes Arch Clin Exp Ophthalmol 2012; 250: 1321–1325.
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: 239–242.
Haigis W, Lege B, Miller N, Schneider B . Comparison of immersion ultrasound biometry and partial coherence interferometry for intraocular lens calculation according to Haigis. Graefes Arch Clin Exp Ophthalmol 2000; 239: 765–773.
Fontes BM, Fontes BM, Castro E . Intraocular lens power calculation by measuring axial length with partial optical coherence and ultrasonic biometry. Arq Bras Oftalmol 2011; 74: 166–170.
Haigis W . Matrix-optical representation of currently used intraocular lens power formulas. J Refract Surg 2009; 25: 229–234.
Hoffer KJ . The Hoffer Q formula: a comparison of theoretic and regression formulas. J Cataract Refract Surg 1993; 19: 700–712.
Holladay JT, Prager TC, Chandler TY, Musgrove KH, Lewis JW, Ruiz RS . A three-part system for refining intraocular lens power calculations. J Cataract Refract Surg 1988; 14: 17–24.
Retzlaff JA, Sanders DR, Kraff MC . Development of the SRK/T intraocular lens implant power calculation formula. J Cataract Refract Surg 1990; 16: 333–340.
Olsen T . Prediction of the effective postoperative (intraocular lens) anterior chamber depth. J Cataract Refract Surg 2006; 32: 419–424.
Aristodemou P, Knox Cartwright NE, Sparrow JM, Johnston RL . Formula choice: Hoffer Q, Holladay 1, or SRK/T and refractive outcomes in 8108 eyes after cataract surgery with biometry by partial coherence interferometry. J Cataract Refract Surg 2011; 37: 63–71.
Sheard RM, Smith GT, Cooke DL . Improving the prediction accuracy of the SRK/T formula: the T2 formula. J Cataract Refract Surg 2010; 36: 1829–1834.
MacLaren RE, Natkunarajah M, Riaz Y, Bourne RR, Restori M, Allan BD . Biometry and formula accuracy with intraocular lenses used for cataract surgery in extreme hyperopia. Am J Ophthalmol 2007; 143: 920–931.
Wang JK, Hu CY, Chang SW . Intraocular lens power calculation using the IOLMaster and various formulas in eyes with long axial length. J Cataract Refract Surg 2008; 34: 262–267.
Olsen T . Improved accuracy of intraocular lens power calculation with the Zeiss IOLMaster. Acta Ophthalmol Scand 2007; 85: 84–87.
Narváez J, Zimmerman G, Stulting RD, Chang DH . Accuracy of intraocular lens power prediction using the Hoffer Q, Holladay 1, Holladay 2, and SRK/T formulas. J Cataract Refract Surg 2006; 32: 2050–2053.
Aristodemou P, Knox Cartwright NE, Sparrow JM, Johnston RL . Intraocular lens formula constant optimization and partial coherence interferometry biometry: Refractive outcomes in 8108 eyes after cataract surgery. J Cataract Refract Surg 2011; 37: 50–62.
Schelenz J, Kammann J . Comparison of contact and immersion techniques for axial length measurement and implant power calculation. J Cataract Refract Surg 1989; 15: 425–428.
Goyal R, North RV, Morgan JE . Comparison of laser interferometry and ultrasound A-scan in the measurement of axial length. Acta Ophthalmol Scand 2003; 81: 331–335.
Haigis W User Group for Laser Interference Biometry. [Online] 2013. Available from http://www.augenklinik.uni-wuerzburg.de/ulib/index.htm. (Accessed 29 September 2013).
Haigis W User Group for Laser Interference Biometry. [Online] 2013. Available from http://www.augenklinik.uni-wuerzburg.de/ulib/czm/dload.htm. (Accessed 9 September 2013).
Hill W IOL Power Calculations Physician Downloads. [Online] 2013. Available from http://www.doctor-hill.com/physicians/download.htm. (Accessed 29 September 2013).
Jasvinder S, Khang TF, Sarinder KK, Loo VP, Subrayan V . Agreement analysis of LENSTAR with other techniques of biometry. Eye 2011; 25: 717–724.
Sanders DR, Retzlaff J, Kraff MC . Comparison of the SRK II formula and other second generation formulas. J Cataract Refract Surg 1988; 14: 136–141.
Eom Y, Kang SY, Song JS, Kim HM . Use of corneal power-specific constants to improve the accuracy of the SRK/T formula. Ophthalmology 2013; 120: 477–481.
Olsen T, Løgstrup N, Olesen H, Corydon L . Using the surgical result in the first eye to calculate intraocular lens power for the second eye. J Cataract Refract Surg 1993; 19: 36–39.
Jabbour J, Irwig L, Macaskill P, Hennessy MP . Intraocular lens power in bilateral cataract surgery: whether adjusting for error of predicted refraction in the first eye improves prediction in the second eye. J Cataract Refract Surg 2006; 32: 2091–2097.
Covert DJ, Henry CR, Koenig SB . Intraocular lens power selection in the second eye of patients undergoing bilateral, sequential cataract extraction. Ophthalmology 2010; 117: 49–54.
Aristodemou P, Knox Cartwright NE, Sparrow JM, Johnston RL . First eye prediction error improves second eye refractive outcome results in 2129 patients after bilateral sequential cataract surgery. Ophthalmology 2011; 119: 1701–1709.
Jivrajka RV, Shammas MC, Shammas HJ . Improving the second-eye refractive error in patients undergoing bilateral sequential cataract surgery. Ophthalmology 2012; 119: 1097–1101.
International Organisation for Standardisation. Ophthalmic Implants - Intraocular Lenses - Part 2: Optical Properties and Test Methods. Geneva, Switzerland: ISO; 2000. Report No.: ISO 11979–2.
Zudans JV, Desai NR, Trattler WB . Comparison of prediction error: labeled versus unlabeled intraocular lens manufacturing tolerance. J Cataract Refract Surg 2012; 38: 394–402.
Silver N . The Prediction Learning Curve. In The Signal and the Noise - The Art and Science of Prediction. Penguin Books Ltd: London, 2012 pp 311–315.
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Appendix
Appendix
Prediction error (PE)
PE is the difference in dioptres between the actual and intended refractive outcome in a particular patient, and is usually calculated such that the PE is negative for an outcome more myopic that intended and positive for a hyperopic outcome:
Mean error (ME)
ME is the arithmetic mean of the prediction errors from a cohort of patients:
ME indicates on average how close the outcome is to the intended target; a negative value indicates that outcomes tend to be more myopic than intended and a positive ME indicates a hyperopic tendency.
Mean absolute error (MAE)
MAE is the mean of the absolute prediction errors in a cohort (ie, the prediction errors ignoring the sign):
The MAE is often used as an indicator of the spread (or dispersion) of refractive outcomes, and if the ME of the data is zero and the prediction errors are normally distributed, then the MAE is approximately 80% of the standard deviation.13 If, however, the ME is non-zero, then this relationship does not hold and it is difficult to infer the dispersion of the outcomes from the MAE in this case. The standard deviation, interquartile range, or the proportion of eyes within a particular range may be a better indicator of the spread of outcomes. Despite its shortcomings MAE has become established in the literature, and may be a useful single figure for comparing data sets as long as its limitations are understood.
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Sheard, R. Optimising biometry for best outcomes in cataract surgery. Eye 28, 118–125 (2014). https://doi.org/10.1038/eye.2013.248
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DOI: https://doi.org/10.1038/eye.2013.248
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