Improved prediction of intraocular lens power using partial coherence interferometry

Findl, Oliver; Drexler, Wolfgang; Menapace, Rupert; Heinzl, Harald; Hitzenberger, Christoph K.; Fercher, Adolf Friedrich

doi:10.1016/s0886-3350(00)00699-4

Cited by 177 publications

(110 citation statements)

References 32 publications

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“…Further, the precision achieved with partial coherence laser interferometry was shown to be 10 times better than that of ultrasound in earlier studies. 16,17 The data from our study show that there is a tendency for hyperopic shift in eyes that undergo partial coherence laser interferometry. This is probably because the axial lengths are measured approximately 100 m longer than with applanation ultrasound.…”

Section: Discussionmentioning

confidence: 67%

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Partial coherence laser interferometry vs conventional ultrasound biometry in intraocular lens power calculations

Rajan

Keilhorn

Bell

2002

Eye

186

136

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Aims The purpose of the study was to compare optical biometry based on partial coherence laser interferometry (PCLI) principle to conventional ultrasound biometry in the accuracy of intraocular lens (IOL) power calculations. The role of partial coherence laser interferometry in pseudophakic axial length measurement was analysed in the study. Methods In a prospective randomised clinical trial, 100 patients undergoing phacoemulsification cataract surgery were randomised to undergo biometry by either partial coherence laser interferometry (IOL Master) or the applanation ultrasound technique. The IOL material, design and the IOL formula were standardized. The mean error and mean absolute error were calculated and compared using paired t-tests. Results One hundred patients were included in this prospective randomised trial, of whom 50 patients underwent optical biometry and 50 patients had biometry by applanation ultrasound. The mean age of patients in the PCLI group was 67 ± 6 yrs as compared to 71 ± 8 yrs in the ultrasound group (P Ͼ 0.

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Section: Discussionmentioning

confidence: 67%

“…Other studies have shown an improvement in predictive value up to 27%. 16,17 It is possible to achieve better predictive value with PCLI by altering the A-constant. However we did not alter the A-constant in this study.…”

Section: Discussionmentioning

confidence: 99%

Partial coherence laser interferometry vs conventional ultrasound biometry in intraocular lens power calculations

Rajan

Keilhorn

Bell

2002

Eye

186

136

View full text Add to dashboard Cite

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“…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%

“…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%

Benchmark standards for refractive outcomes after NHS cataract surgery

Gale

Saldaña

Johnston

et al. 2007

Eye

205

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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“…20,21 The benefits of customising A constants are easy to apply to NHS departments by routinely performing biometry calculations using appropriate software. Cataract surgery is one of the most commonly performed operations in the UK, and it is clear from this study that very few eye departments are appropriately auditing their biometry service and acting on the results.…”

Section: Discussionmentioning

confidence: 99%

National Biometry Audit

Gale

Saha

Johnston³

2004

Eye

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Purpose To determine compliance with the Royal College of Ophthalmologists' (RCOphth) biometry guidelines. Method A structured telephone questionnaire of individuals who perform biometry in all eye departments in the United Kingdom (UK). Results A biometrist was interviewed in 107 of the UK's 178 eye departments. Nurses alone run the biometry service in 58% of departments, orthoptists alone in 13%, junior doctors alone in 6%, optometrists alone in 3%, and a combination of staff in 20%. Of the staff interviewed, 37% had been on external biometry training courses.One intraocular lens (IOL) calculation formula was used for all eyes in 61% of departments with 17% using the obsolete SRK II formula, 36% of departments used two or more formulae and only 4% adhered to the RCOphth guidelines to use Hoffer Q in eyes with axial lengths o22.0 mm, an average of all three formulae in eyes between 22.0 and 24.5 mm, Holladay in eyes between 24.6 and 26.0 mm, and SRK/T in eyes 426.0 mm. Audit of refractive results was claimed by 71% of units but in only 17 (16%) did the biometrist know the percentage of eyes with a prediction error r1 D. Conclusion This study demonstrates poor awareness and/or implementation of the RCOphth biometry guidelines and indicates that audits are either not highlighting poor results or are not resulting in a change in practice. The guidelines should be updated to emphasise the importance of customising A constants and to set benchmark standards for prediction error.

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Improved prediction of intraocular lens power using partial coherence interferometry

Cited by 177 publications

References 32 publications

Partial coherence laser interferometry vs conventional ultrasound biometry in intraocular lens power calculations

Partial coherence laser interferometry vs conventional ultrasound biometry in intraocular lens power calculations

Benchmark standards for refractive outcomes after NHS cataract surgery

National Biometry Audit

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