National Biometry Audit II

Gale, Richard; Saha, Niladri; Johnston, Robert L.

doi:10.1038/sj.eye.6701778

Cited by 24 publications

(23 citation statements)

References 9 publications

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“…A study of 22 paediatric eyes undergoing 17 although it is acknowledged that immersion ultrasonography requires skill and experience 18 and is not available in many units in the United Kingdom. 19 When using A-scan ultrasound, the speed of the ultrasound waves is affected by the density of the material through which it is passing. Very dense cataracts may influence the final measurement to a greater extent in shorter eyes as the lens makes up a relatively greater proportion of the axial length.…”

Section: Discussionmentioning

confidence: 99%

Paediatric intraocular lens implants: accuracy of lens power calculations

O’Gallagher

Lagan

Mulholland

et al. 2016

Eye

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Purpose This study aims to evaluate the accuracy of lens prediction formulae on a paediatric population. Methods A retrospective case-note review was undertaken of patients under 8 years old who underwent cataract surgery with primary lens implantation in a regional referral centre for paediatric ophthalmology, excluding those whose procedure was secondary to trauma. Biometric and refractive data were analysed for 43 eyes, including prediction errors (PE). Statistical measures used included mean absolute error (MAE), median absolute error (MedAE), Student's t-test and Lin's correlation coefficient. Results The mean PE using the SRK-II formula was +0.96 D (range − 2.47D to +2.41 D, SD 1.33 D, MAE 1.38 D, MedAE 1.55, n = 15). The mean PE was smaller using SRK/ T (−0.18 D, range − 3.25 D to +3.95 D, SD 1.70 D, MAE 1.30 D, MedAE 1.24, n = 27). We performed an analysis of the biometry data using four different formula (Hoffer Q, Holladay 1, SRK-II and SRK/T). Hoffer Q showed a smaller MedAE than other formulae but also a myopic bias. Conclusion Our clinical data suggest SRK/T was more accurate in predicting postoperative refraction in this cohort of paediatric patients undergoing cataract surgery. Hoffer Q may have improved accuracy further.

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Section: Discussionmentioning

confidence: 99%

Paediatric intraocular lens implants: accuracy of lens power calculations

O’Gallagher

Lagan

Mulholland

et al. 2016

Eye

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“…1,8 Customisation of A constants for an intraocular lens is important to eliminate systemic errors that may occur due to the differences in the method of axial length measurement or due to sub-optimal manufacturer's A constants. For the same intraocular lens (IOL), when using PCI compared with acoustic methods of axial length measurement there can be more than 1 D of difference between customised A constants.…”

Section: Discussionmentioning

confidence: 99%

“…2,6,7 Setting a benchmark standard would allow all National Health Service (NHS) cataract services to know whether they are achieving a satisfactory standard. It has previously been suggested, 1,8 based upon studies, [3][4][5][6] that a benchmark of 85-90% of patient undergoing routine cataract surgery should achieve a final spherical equivalent refraction within 1 D of the predicted value.…”

Section: Introductionmentioning

confidence: 99%

“…1 The Royal College of Ophthalmologists (RCOphth) 2004 cataract surgery guidelines state that both optical (partial coherence interferometry (PCI)) and acoustic (ultrasound) methods of axial length measurement can be routinely used, 2 although it has been shown that PCI reduces the prediction error of postoperative refractive outcome. [3][4][5] The RCOphth 2004 guidelines state that each ophthalmology department, if not each surgeon, should personalise the A constant on the basis of continuous audit of the comparison of the predicted and actual spherical equivalent of the postoperative subjective refraction.…”

Section: Introductionmentioning

confidence: 99%

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Benchmark standards for refractive outcomes after NHS cataract surgery

Gale

Saldaña

Johnston

et al. 2007

Eye

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209

131

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Purpose To establish benchmark standards for refractive outcome after cataract surgery in the National Health Service when implementing the 2004 biometry guidelines of the Royal College of Ophthalmologists and customising A constants. Methods Three cycles of prospective data were collected throughout the cataract care pathway on all patients using an electronic medical record system (Medisoft Ophthalmology), between January 2003 and February 2006. The electronic medical record automatically recommends the formula to be used according to the College guidelines and allows A constants to be customised separately for either ultrasound or partial coherence interferometry methods of axial length measurement and for different intraocular lens models. Consultants and trainees performed routine phacoemulsification cataract surgery and new intraocular lens models were introduced during the cycles. Uncomplicated cases with'in-the-bag fixation', achieving 6/12 Snellen acuity or better were included. Community ophthalmic opticians performed refraction at 4 weeks. Results The postoperative subjective refraction was within 1 D of the predicted value in 79.7% of the 952 cases in cycle 1, 83.4% of 2406 cases in cycle 2, and 87.0% of 1448 cases in cycle 3. Conclusions On the basis of our data, using College formula, optimising A constants and partial coherence interferometry, a benchmark standard of 85% of patients achieving a final spherical equivalent within 1 D of the predicted figure and 55% of patients within 0.5 D should be adopted.

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“…7,14 For these eyes ultrasonic axial length measurement is required, and in the UK contact ultrasound is the method of choice with immersion methods rarely used. 15 In general, however, immersion ultrasound produces more accurate predictions than contact ultrasound, 8 approaching or matching those of the optical methods. 16,17 If immersion ultrasound was adopted as the second-line investigation for eyes in which optical biometry fails, then outcomes could be improved from 82.5% within ± 1 D of target 10 to between 85.7 and 94.3%.…”

Section: Axial Length Measurementmentioning

confidence: 99%

Optimising biometry for best outcomes in cataract surgery

Sheard

2013

Eye

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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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National Biometry Audit II

Cited by 24 publications

References 9 publications

Paediatric intraocular lens implants: accuracy of lens power calculations

Paediatric intraocular lens implants: accuracy of lens power calculations

Benchmark standards for refractive outcomes after NHS cataract surgery

Optimising biometry for best outcomes in cataract surgery

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