Partial coherence interferometry: a novel approach to biometry in cataract surgery

Drexler, Wolfgang; Findl, Oliver; Menapace, Rupert; Rainer, Georg; Vass, Clemens; Hitzenberger, Christoph K.; Fercher, Adolf Friedrich

doi:10.1016/s0002-9394(98)00113-5

Cited by 397 publications

(291 citation statements)

References 37 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: 63%

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

Rajan

Keilhorn

Bell

2002

Eye

187

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: 63%

“…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

187

136

View full text Add to dashboard Cite

show abstract

“…[5,6] The measurement mirror moves with constant speed and superimposes the reflected beams from the retina onto the delayed beams from the cornea. [5,6] Then the interference signal is detected and the displacement of the mirror can be precisely obtained. [5,6] The delay of dual beam components equals the axial length.…”

Section: Introductionmentioning

confidence: 99%

“…[5,6] Then the interference signal is detected and the displacement of the mirror can be precisely obtained. [5,6] The delay of dual beam components equals the axial length. [5,6] However, PCI is less useful in measuring AL in eyes with severe media opacity, especially due to posterior subcapsular cataracts (PSC).…”

Section: Introductionmentioning

confidence: 99%

“…[5,6] The delay of dual beam components equals the axial length. [5,6] However, PCI is less useful in measuring AL in eyes with severe media opacity, especially due to posterior subcapsular cataracts (PSC). It is reported that the failure rate of AL measurement using PCI was 4.7-36.6% because of dense nuclear sclerosis, PSC, macular pathology, vitreous opacity, and other similar disorders.…”

Section: Introductionmentioning

confidence: 99%

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Measurement Reliability of Axial Length of the Human Eye by using Partial Coherence Interferometry

Kim¹,

Moon²,

Chae³

et al. 2014

Journal of the Optical Society of Korea

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To investigate the minimum near-infrared ray intensity required (quantifiable threshold value) for consistent measurements of axial length (AL) using partial coherence interferometry (PCI), we attached two polarizing lenses (PL) to two types of PCI (IOLmaster, ALscan). The near-infrared ray intensity of PCI was modified by rotating the axis of one PL at intervals of 5 degrees. The right eye of each volunteer was measured three times and the AL and signal-to-noise ratio (SNR) was recorded five times for each measurement. Reduction of light intensity was theoretically estimated using Malus' Law. AL was measured consistently with both IOLmaster and ALscan until they reached 55 degrees (1.33 % of intensity) and 60 degrees (0.77%), respectively (P = 0.343, Log-rank test). In contrast, SNR decreased as light intensity decreased. In addition, to analyze media opacities that precluded measurement of AL, we retrospectively reviewed the medical records of patients unmeasurable by PCI (ALscan) from May to November 2013. Thirty-eight of 473 eyes (8.0%) could not be measured using ALscan due to media opacities, such as severe posterior subcapsular cataract (PSC, 11 eyes), hypermature cataract (9 eyes), and vitreous hemorrhage (18 eyes). The mean grades of vitreous haze and PSC were 7.72 ± 0.96 and 4.45 ± 1.04, respectively. In conclusion, up to 0.77-1.33% of near-infrared rays decreased, and AL could be measured consistently.

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Short-term Effect of Dorzolamide Hydrochloride on Central Corneal Thickness in Humans With Cornea Guttata

Wirtitsch

Findl²,

Kiss³

et al. 2003

Arch Ophthalmol

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To investigate the short-term effect of dorzolamide hydrochloride, a topical carbonic anhydrase inhibitor, on central corneal thickness in patients with cornea guttata. Design and Methods: In this randomized, placebocontrolled, double-masked, 3-drug crossover study, 20 patients with cornea guttata (mean endothelial cell count, 1321 cells/mm 2) and 8 healthy control subjects (mean endothelial cell count, 2483 cells/mm 2) were included. Study medications included 2% dorzolamide hydrochloride (Trusopt 2% eye drops; Merck & Co Inc, Whitehouse Station, NJ), 0.9% saline solution (saline placebo), and a solution identical to the carrier substance of dorzolamide in Trusopt (carrier placebo). The study drugs were applied 4 times per day for 1 day only. Central corneal thickness measurements were performed using partial coherence interferometry on every study day at baseline and after 24 hours of study medication treatment. Main Outcome Measures: Change in central corneal thickness. Results: The mean thickening in central corneal thickness within 24 hours in eyes with cornea guttata treated with dorzolamide, saline placebo, and carrier placebo was 12.0 µm (95% confidence interval [CI], 7.0-17.1 µm), 0.6 µm (95% CI, −1.0 to 2.2 µm), and 1.3 µm (95% CI, −0.1 to 2.6 µm), respectively. Conclusion: Application of dorzolamide for 1 day results in a slight but statistically significant thickening of central corneal thickness in patients with cornea guttata.

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Partial coherence interferometry: a novel approach to biometry in cataract surgery

Cited by 397 publications

References 37 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

Measurement Reliability of Axial Length of the Human Eye by using Partial Coherence Interferometry

Short-term Effect of Dorzolamide Hydrochloride on Central Corneal Thickness in Humans With Cornea Guttata

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