Keratometric Index Obtained by Fourier-Domain Optical Coherence Tomography

Hua, Yanjun; Stojanovic, Aleksander; Utheim, Tor Paaske; Chen, Xiangjun; Ræder, Sten; Huang, Jinhai; Wang, Qinmei

doi:10.1371/journal.pone.0122441

Cited by 8 publications

(5 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Moreover, in another study using SS-OCT, Xie et al [ 18 ] found that CCT was 547.56 µm, which is almost identical to the value reported in the present study (546.65 µm) [ 19 ]. Furthermore, Hua et al [ 20 ] analyzed mean CCT and certain corneal parameters using RTVue (FD-OCT); although their CCT value (544.98 ± 33.09 µm) was comparable to our value (546.65 ± 28.69) [ 20 ], they did not evaluate sex-specific differences in this parameter. The Namil study was a multicenter study including patients over 40 years of age who were residents of central South Korea; in that study, mean CCT was slightly low (530.9 µm), but this parameter was significantly different between sexes, being 5.9 µm thicker in males ( p = 0.001) [ 21 ].…”

Section: Discussioncontrasting

confidence: 83%

“…In a similar study using RTVue, this value for the 3 mm central circle was significantly lower (by 1.21 D), which is not consistent with the results of the present study [ 23 ].The results of Fourier indices of corneal parameters obtained in the present study are partly consistent with those obtained in a study by Tanabe et al [ 24 ], who calculated the above parameters using Fourier analysis on the basis of images obtained with videokeratography; the mean values of the four main parameters, namely spherical power, regular astigmatism, asymmetry, and higher-order irregularities, were 43.97, 0.5, 0.35, and 0.11 D, respectively, in Tanabe et al’s study [ 24 ] and 43.09, 0.5, 0.24, and 0.15 D, respectively, in our study. Hua et al [ 20 ] also assessed the mean power of the cornea using RTVue. For the 3 mm central circle, the power was 43.01 ± 1.53 D, which is practically identical to the value obtained in the present study (43.09 ± 1.27 D).…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Swept Source Optical Coherence Tomography Analysis of the Selected Eye’s Anterior Segment Parameters

Dembski

Nowińska²,

Ulfik-Dembska

et al. 2021

JCM

View full text Add to dashboard Cite

Background: The present study determined the mean reference values of the anterior segment parameters of the selected eye using swept source optical coherence tomography (SS-OCT) in healthy Caucasian participants. Methods: A total of 166 volunteers (age 54–79 years), women (n =92) and men (n =74), were analyzed. One eye of each subject was randomly selected for anterior segment imaging. The anterior segment of the eye was scanned with CASIA2. The analyzed anterior segment parameters were divided into three groups, namely parameters of the cornea, lens, and angle. Results: The OCT (e.g., Ks, Kf, pKf, pKs, and central corneal thickness) and Fourier parameters of the cornea were significantly different between females and males. The iridocorneal angle was the smallest in the upper quadrant for all distance from the apex of the angle (250, 500, and 750 µm). Conclusions: Therefore, SS-OCT enables the analysis of parameters of the cornea, anterior chamber, lens, and iridocorneal angle, highlighting its clinical utility. Sex-specific differences in the analyzed parameters should be taken into account during the diagnosis of corneal diseases. The configuration of the filtration angle is an important marker during glaucoma diagnosis and drainage implant surgery. Measurements with CASIA 2is characterized by very good repeatability.

show abstract

Section: Discussioncontrasting

confidence: 83%

Section: Discussionmentioning

confidence: 99%

Swept Source Optical Coherence Tomography Analysis of the Selected Eye’s Anterior Segment Parameters

Dembski

Nowińska²,

Ulfik-Dembska

et al. 2021

JCM

View full text Add to dashboard Cite

show abstract

“…To measure the corneal curvature, Placido-disc based topography techniques with 9 rings each 256 points in a 5.5-mm zone are projected onto the cornea, and corneal curvature of 2-mm, 2.5-mm and 3-mm central corneal zone can be obtained[ 15 ]. The standard keratometric index of 1.3375 is used for calculating the keratometer readings[ 26 , 27 ]. In the present study, the AL, CCT, ACD, PD, LT, CD and keratometer readings data of the 2.5 mm zone for each scan were collected.…”

Section: Methodsmentioning

confidence: 99%

Precision (repeatability and reproducibility) of ocular parameters obtained by the Tomey OA-2000 biometer compared to the IOLMaster in healthy eyes

et al. 2018

Self Cite

View full text Add to dashboard Cite

PurposeTo assess the precision (repeatability and reproducibility) of ocular parameters measured by the Tomey OA-2000 biometer, and to compare them with those measured by the IOLMaster.MethodsIn this prospective study, the right eyes of 108 healthy subjects were included. Three consecutive scans were obtained by 2 observers using the Tomey OA-2000, and in the same session one observer used the IOLMaster (version 5.4.4.0006) for the measurements. About 1 week later, 3 scans were obtained by one observer using the Tomey OA-2000. The axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), keratometer readings, pupil diameter (PD) and corneal diameter (CD) values measured by the Tomey OA-2000 and IOLMaster were analyzed. The coefficient of variation (CoV), intraclass correlation coefficient (ICC), within subject standard deviation (Sw) and 2.77Sw were calculated to assess the repeatability and reproducibility. The paired t test and Bland-Altman plots were used to analyze the differences and agreements of parameters measured by the two devices, respectively.ResultsIntraobserver repeatability, and interobserver and intersession reproducibility of the AL, CCT, ACD, LT, Kf, Ks, Km, PD and CD values measured by the Tomey OA-2000 biometer showed a CoV of less than 1% except that for PD, and an ICC of more than 0.97 except that for PD and CD. The AL, Kf, Ks, Km and CD values measured by the Tomey OA-2000 were 0.058 ± 0.094 mm, 0.088± 0.150 diopters (D), 0.163 ± 0.170 D, 0.127 ± 0.117 D and 0.171 ± 0.217 mm lower than those measured by the IOLMaster, respectively (all Ps < 0.05). However, the ACD values from the two devices were comparable (P = 0.169). The 95% linite of agreement (LoA) of the AL, ACD, CD and all keratometer readings were no more than 0.24 mm, 0.14 mm 0.60 mm and 0.5 D, respectively.ConclusionExcept for the PD and CD, the ocular parameters measured by the Tomey OA-2000 were highly repeatable and reproducible. Except for the CD value, there was good agreement of ocular parameters measured by the Tomey OA-2000 and the IOLMaster in healthy eyes.

show abstract

“…The contact lens base curve was then computed using the standard formula used for children and adults where the index of refraction of the cornea and index of refraction of air were constant values. 7 The higher CCC measurement was represented by the K1 taken from the handheld auto keratometer. There is an inverse relationship between K1 and base curve.…”

Section: Methodsmentioning

confidence: 99%

Age-based Estimation of Contact Lens Base Curve in Filipino Infants

Astudillo

Tan²,

Cruz

et al. 2021

Acta Med Philipp

View full text Add to dashboard Cite

Objective. To create an age-based formula to estimate the base curve needed for contact lens fitting using measured central corneal curvature (CCC) with a handheld auto keratometer from ophthalmologically normal infants.Methods. This is a prospective cross-sectional study involving 70 ophthalmologically normal full-term infants aged 0 to 12 months. The infants were divided into four groups: 0-3 months, >3-6 months, >6-9 months and >9-12 months. CCC was measured with a handheld auto keratometer and was used to compute for the base curve. Differences in CCC between the four groups were measured and linear regression models were used for formula creation.Results. The mean CCC was highest in group 1 at 45.5 ±2.4 diopters (D). These values slowly decreased as age increased. A formula predictive of the base curve based on the infants age was derived using linear regression analysis. It predicted that for every month increase in age, there is a 0.063 millimeter increase in the base curve (p<0.001). Conclusion.Infant CCC is highest at birth and gradually decreases as age increases. The formula can predict the base curve needed for contact lens fitting in infants without the need for a handheld autokeratometer.

show abstract

Keratometric Index Obtained by Fourier-Domain Optical Coherence Tomography

Cited by 8 publications

References 23 publications

Swept Source Optical Coherence Tomography Analysis of the Selected Eye’s Anterior Segment Parameters

Swept Source Optical Coherence Tomography Analysis of the Selected Eye’s Anterior Segment Parameters

Precision (repeatability and reproducibility) of ocular parameters obtained by the Tomey OA-2000 biometer compared to the IOLMaster in healthy eyes

Age-based Estimation of Contact Lens Base Curve in Filipino Infants

Contact Info

Product

Resources

About