Search results for "Biometry"
showing 10 items of 80 documents
Evaluation of the practicality of optical biometry and applanation ultrasound in 253 eyes
2003
Abstract Purpose To evaluate the percentage of eyes that could not be measured using optical biometry and ultrasound applanation and the reasons. Setting Department of Ophthalmology, Johannes Gutenberg-University Hospital, Mainz, Germany. Methods Optical biometry (IOLMaster®, Carl Zeiss Meditec AG) and A-scan ultrasound biometry were performed consecutively in 253 eyes scheduled for cataract surgery the next day. Lens opacities were evaluated with the Opacity Lensmeter (Interzeag), and a slitlamp examination and measurement of visual acuity were performed. The 2 techniques were compared in terms of the rate of and reasons for primary measurement failure. Results Measurement with the IOLMast…
A simple description of age-related changes in crystalline lens thickness.
2010
Purpose An increase in lens thickness is often described as a linear function of age. However, contradictory opinions exist about whether the lens thickness continues to increase after 50 years of age. Differences in slope exist between this increase in younger and older people, but these findings are inconsistent with the linear behavior of an increase in the lens thickness throughout life. We investigated among different functions, including slope variation, which would be the best to show the relation between lens thickness and age. An available model portraying lens growth could be advantageous in many practical applications. The possibility of differences between sexes in lens thicknes…
Repeatability assessment of biometric measurements with different refractive states and age using a swept-source biometer
2018
Background We aim to assess if refractive error or age may influence the repeatability of measurements using a swept-source biometer. Methods A total of 61 subjects were evaluated with IOLMaster 700 acquiring measurements of axial length (AL), central corneal thickness (CCT), white-to-white distance (WTW), anterior aqueous depth (AQD), lens thickness (LT), and keratometry (K) readings. Repeatability was evaluated classifying the sample according to the refractive state and age by the calculation of the within-subject standard deviation (Sw), coefficient of repeatability, and intraclass correlation coefficient. Results Very similar Sw was acquired among groups for AL, CCT, and WTW. Differenc…
Reproducibility of optical biometry using partial coherence interferometry: intraobserver and interobserver reliability
2001
Abstract Purpose: To evaluate the intraobserver and interobserver variability in axial length (AL), anterior chamber depth (ACD), and corneal radius measurements using an optical biometry instrument based on partial coherence interferometry (PCI). Setting: Johannes Gutenberg University, Mainz, Germany. Methods: In this observational case series and interobserver reliability trial, 30 healthy, emmetropic to moderately myopic eyes of 15 volunteers were evaluated. The AL, ACD, and corneal radius were measured 20 times in 10 eyes by 1 observer to evaluate the intraobserver variability. To evaluate the interobserver variability, the measurements were taken in 20 eyes by 5 different observers. Me…
Interchangeability among five devices that measure anterior eye distances.
2014
The aim was to study the interchangeability of various devices that measure anterior chamber depth (ACD) and white-to-white (WTW) distance.Eighty right eyes of eighty patients aged 20 to 40 years were included. Their spherical equivalent ranged from -4.25 to +1.00 dioptres. Each eye's ACD and the WTW distance were measured using the following devices: a Castroviejo surgical calliper, CA-200F Corneal Analyser, Orbscan II, Pentacam HR and IOLMaster 500.The Pentacam HR measured significantly greater ACD (p0.01) than the other two devices, whereas IOLMaster 500 and Orbscan II yielded comparable (p0.01) distances. Nonetheless, in every device comparison, the mean difference was within clinically…
Ocular biometric repeatability using a new high-resolution swept-source optical coherence tomographer.
2020
To assess the repeatability of ocular biometric parameters using a high-resolution imaging device.74 healthy right eyes were included in this study. Five-repeated measurements were taken with ANTERION high-resolution swept-source optical coherence tomographer (SS-OCT) to measure: corneal thickness (central and at 2, 4 and 6-mm diameters), aqueous depth (AD), lens thickness (LT), anterior chamber volume (ACV), axial length (AL), and pupil (diameter and position). The intrasubject standard deviation (SWe have not found statistically significant differences between repeated measurements (p 0.05). The mean difference for corneal thickness was between -0.08 and 0.28 μm. For AD and LT was 0.004 …
Five-year functional outcomes and vault of -20 diopter myopic phakic intraocular lens implantation.
2015
Purpose To evaluate refractive and visual outcomes and complications associated with phakic intraocular lens (pIOL) implantation to correct high myopia. Settings Fernandez-Vega Ophthalmological Institute, Oviedo, Spain. Design Retrospective observational case series. Methods Uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA), refraction, vault, and adverse effects were evaluated after 5 years with Visian ICMV4 pIOL. Results Mean spherical equivalent (SE) dropped from −18.32 ± 2.37 diopters (D) preoperatively to −0.88 ± 0.52D 5 years postoperatively; 61% of eyes were within ±0.75 D of the target. The mean Snellen decimal CDVA and UDVA were 0.73 ± 0.23 and 0…
Objective vs Subjective Vault Measurement After Myopic Implantable Collamer Lens Implantation
2009
PURPOSE: To evaluate the relationship between subjective measurements of vault and objective values measured with Visante optical coherence tomography (OCT) in eyes receiving an implantable contact lens (ICL) for myopia correction. DESIGN: Observational cross-sectional study. METHODS: SETTING: Fernández-Vega Ophthalmological Institute, Oviedo, Spain. PATIENTS: Four hundred and fifty-two eyes from 246 patients were elected to be implanted with a Visian ICL V4 (STAAR Surgical Inc, Monrovia, California, USA). OBSERVATION PROCEDURES: Subjective and objective measurements of vault after implantation of ICL. MAIN OUTCOME MEASURES: Subjective vault classified in 5 levels assessed using an optical …
Evaluation of Physiological Parameters on Discomfort Glare Thresholds Using LUMIZ 100 Tool
2021
Purpose To assess the links between discomfort glare sensitivity and physiological factors such as eye biometry, refraction, skin phototype, age, and gender among a large sample of healthy human subjects. Methods A total of 489 participants who were 20 to 70 years old (241 men, 248 women) underwent discomfort glare threshold measurements via the LUMIZ 100. Eye biometry and optical quality were measured using a Zeiss IOLMaster 700 biometer and i.Profiler aberrometer. Iris color, skin tone, age, gender, eyeglasses use, chronotype, fatigue level, self-evaluation of light sensitivity, and time spent outdoors were determined. Statistical analysis was carried out using nonparametric Mann–Whitney …
Multisectorial changes in the ciliary muscle during accommodation measured with high-resolution optical coherence tomography
2019
ABSTRACT Purpose: To measure changes in the anterior ciliary muscle during accommodation at the nasal, superior, temporal, and inferior sectors by means of an anterior chamber optical coherence tomographer, and correlate them with vergence changes. Methods: Twenty-four subjects with healthy, phakic eyes, whose mean age was 27.1 ± 8.9 years, underwent measurement with an anterior chamber optical coherence tomographer. The anterior ciliary muscle was measured at the nasal, temporal, superior, and inferior sectors for 0, -1, -2, and -3 D of vergence. A linear model was used to assess the correlation of each eye parameter with the accommodative demand. Results: The anterior ciliary muscle area …