The publication presents a comparative study of two fibre-optic sensors in the application of heart rate (HR) and respiratory rate (RR) monitoring of the human body. After consultation with clinical practitioners, two types of non-invasive measuring and analysis systems based on fibre Bragg grating (FBG) and fibre-optic interferometer (FOI) have been designed and assembled. These systems use probes (both patent pending) that have been encapsulated in the bio-compatible polydimethylsiloxane (PMDS). The main advantage of PDMS is that it is electrically non-conductive and, as well as optical fibres, has low permeability. The initial verification measurement of the system designed was performed on four subjects in a harsh magnetic resonance (MR) environment under the supervision of a senior radiology assistant. A follow-up comparative study was conducted, upon a consent of twenty volunteers, in a laboratory environment with a minimum motion load and discussed with a head doctor of the Radiodiagnostic Institute. The goal of the laboratory study was to perform measurements that would simulate as closely as possible the environment of harsh MR or the environment of long-term health care facilities, hospitals and clinics. Conventional HR and RR measurement systems based on ECG measurements and changes in the thoracic circumference were used as references. The data acquired was compared by the objective Bland−Altman (B−A) method and discussed with practitioners. The results obtained confirmed the functionality of the designed probes, both in the case of RR and HR measurements (for both types of B−A, more than 95% of the values lie within the ±1.96 SD range), while demonstrating higher accuracy of the interferometric probe (in case of the RR determination, 95.66% for the FOI probe and 95.53% for the FBG probe, in case of the HR determination, 96.22% for the FOI probe and 95.23% for the FBG probe).
- MeSH
- Artifacts MeSH
- Respiratory Rate physiology MeSH
- Adult MeSH
- Electrocardiography MeSH
- Phonocardiography MeSH
- Interferometry instrumentation MeSH
- Middle Aged MeSH
- Humans MeSH
- Human Body MeSH
- Magnetic Resonance Imaging * MeSH
- Young Adult MeSH
- Optical Fibers MeSH
- Optical Phenomena * MeSH
- Signal Processing, Computer-Assisted MeSH
- Motion MeSH
- Heart Rate physiology MeSH
- Fiber Optic Technology instrumentation MeSH
- Wavelet Analysis MeSH
- Check Tag
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Young Adult MeSH
- Male MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- Comparative Study MeSH
Úvod: Cílem naší práce bylo srovnat výsledky pachymetrie a keratometrie rohovky na třech různých oftalmologických přístrojích s touto funkcí a zjistit, zda jsou tyto přístroje v praxi vzájemně zastupitelné. Metodika: Do studovaného souboru bylo zařazeno 43 zdravých osob s normálním očním nálezem (29 žen a 14 mužů, průměrný věk 25 let ± 3,5). Centrální tloušťka rohovky (CCT) byla měřena na přístroji Pentacam HR, Allegro BioGraph a pomocí ultrazvukové pachymetrie na přístroji OcuScan RxP. Zakřivení rohovky ve dvou hlavních meridiánech (K1, K2) bylo měřeno na přístrojích Pentacam HR, Allegro BioGraph a pomocí automatického keratometru. Výsledky: Průměrný rozdíl v hodnotě K1 mezi Biographeem a autokeratometrem byl 0,01 ± 0,31 D, mezi BioGraphem a Pentacamem 0,06 ± 0,23 D a mezi autokeratometrem a Pentacamem 0,05 ± 0,34 D. Průměrný rozdíl v hodnotě K2 mezi BioGraphem a autokeratometrem byl 0,29 ± 0,45 D, mezi BioGraphem a Pentacamem 0,11 ± 0,28 D a mezi autokeratometrem a Pentacamem 0,19 ± 0,44 D. Zjištěné rozdíly v keratometrii byly ve všech případech statisticky významné (p < 0,05). Průměrný rozdíl v CCT mezi BioGraphem a ultrazvukem byl 4,57 ± 7,84 μm, mezi BioGraphem a Pentacamem 4,33 ± 7,55 μm a mezi ultrazvukem a Pentacamem 8,90 ± 7,49 μm. Rozdíly v tloušťce rohovky byly rovněž statisticky významné (p < 0,05). Závěr: Podle našich výsledků se mohou hodnoty keratometrie a CCT mezi testovanými přístroji významně lišit a nejsou tedy v praxi vzájemně zastupitelné.
Introduction: The aim of our study was to compare keratometry and central corneal thickness measurements obtained with three different ophthalmic devices and to decide if they can be used interchangeably in clinical practice. Methods: 43 healthy persons were included in the study (29 women and 14 men, average age 25 ± 3.5 years). Central corneal thickness (CCT) was measured with the Scheimpflug HR imaging system (Pentacam), Allegro BioGraph and with ultrasound pachymetry (RXP OcuScan). Keratometry in two main meridians of the cornea (K1, K2) was measured with Pentacam, Allegro BioGraph and automated keratometry. Results: The mean difference in K1-readings was 0.01 ± 0.31 D for BioGraph vs. automated keratometry, 0.06 ± 0.23 D for BioGraph vs. Pentacam and 0.05 ± 0.34 D for automated keratometry and Pentacam. The mean difference in K2-readings was 0.29 ± 0.45 D for BioGraph vs. automated keratometry, 0.11 ± 0.28 D for BioGraph vs. Pentacam and 0.19 ± 0.44 D for automated keratometry and Pentacam. The interdevice differences were in all cases statistically significant (p < 0.05). The mean difference in CCT was 4.57 ± 7.84 μm for BioGraph vs. ultrasound, 4.33 ± 7.55 μm for BioGraph vs. Pentacam and 8.90 ± 7.49 μm for ultrasound vs. Pentacam. The interdevice differences in CCT were also statistically significant (p < 0.05). Conclusion: Our results suggest that the measurements of keratometry and CCT may differ significantly between the tested machines and therefore should not be used interchangeably in clinical practice.
- Keywords
- CCT, Pentacam, BioGraph,
- MeSH
- Adult MeSH
- Interferometry instrumentation utilization MeSH
- Humans MeSH
- Observer Variation MeSH
- Reproducibility of Results MeSH
- Cornea anatomy & histology pathology MeSH
- Corneal Topography methods instrumentation statistics & numerical data MeSH
- Ultrasonography methods instrumentation MeSH
- Check Tag
- Adult MeSH
- Humans MeSH
- Male MeSH
- Publication type
- Comparative Study MeSH
V prospektivní studii 56 pacientů (67 očí) s kataraktou autoři srovnali axiální délku očí změřenou simultánně standardní ultrazvukovou biometrií a parciální koherentní interferometrií (optickou biometrií) s ohledem na výslednou pooperační refrakci operovaných očí. Dioptrická hodnota intraokulární čočky (IOČ)pro predikovanou pooperační refrakci byla stanovena pomocí vzorce SRK II. Rozdíl mezi předpokládanou a aktuální pooperační refrakcí v dioptriích byl hodnocen 3 měsíce po operaci šedého zákalu. Axiální délka změřená ultrazvukem se významně lišila od axiální délky změřené optickou biometrií (p=0,016). Také dioptrická hodnota IOČ vypočítaná podle axiální délky změřené ultrazvukem se významně lišila od dioptrické hodnoty IOČ vypočítané podle axiální délky oka změřené optickou biometrií (p=0,003). Rozdíl mezi očekávanou a skutečnou pooperační refrakcí v dioptriích však nebyl statisticky významný (p=0,384) ani s ohledem na použitou metoduměření axiální délky. Parciální koherentní interferometrie (optická biometrie) je přesná a reprodukovatelná metoda pro změření axiální délky oka před operací katarakty. Nelze ji však použít u pokročilých katarakt s neprůhlednou optickou osou, proto je stále nutná záloha standardní ultrazvukové biometrie.
In theprospectivestudyof56patientswithcataract (67eyes)theauthorscompared axial length biometry) regarding to postoperative refraction of the eyes. Dioptric power of the intraocular lens (IOL) was determined by SRK II. formula. The difference between predicted and actual postoperative refraction in the spherical equivalent were compared 3 months postoperatively. Axial length measured by ultrasound differed significantly from the axial length measured by optical biometry (p=0.016). Dioptric power of IOL calculated according to the axial length measured by ultrasound was significantly different from the dioptric power of IOL calculated according to the axial length measured by optical biometry (p=0.003). The difference between predicted and actual postoperative refraction was not statistically significant (p=0.384) even if we considered both type of measurement. In conclusion, we found partial coherence interferometry was an accurate and reproducible method for measurement of axial length of the eyebefore cataract surgery. In the cases of advanced dense cataracts backup of ultrasonic biometry is still necessary.
- MeSH
- Biometry methods instrumentation MeSH
- Cataract Extraction MeSH
- Interferometry methods instrumentation MeSH
- Cataract diagnosis ultrasonography MeSH
- Humans MeSH
- Postoperative Period MeSH
- Preoperative Care MeSH
- Refraction, Ocular MeSH
- Ultrasonography methods MeSH
- Check Tag
- Humans MeSH
- Publication type
- Review MeSH
- Comparative Study MeSH
