Search

Aims To assess the repeatability and reproducibility of the ocular measurements obtained with the Suoer SW-9000 μm Plus, a new fully automatic biometer based on optical low coherence reflectometry (OLCR) biometer, and to compare them to those obtained by a swept-source optical coherence tomography (SS-OCT)- based biometer. Methods This prospective study consisted of 115 eyes of 115 healthy subjects. The measurements were taken by the two optical biometers in random order. The measured parameters were axial length (AL), central corneal thickness (CCT), aqueous depth (AQD), anterior chamber depth (ACD), mean keratometry (Km), lens thickness (LT) and corneal diameter (CD). To evaluate the intraobserver repeatability and interobserver reproducibility, the within-subject SD, test-retest variability, coefficient of variation (CoV) and intraclass correlation coefficient (ICC) were adopted. The Bland-Altman plot was drawn to assess the agreement. Results The repeatability and reproducibility of all parameters for the new device were excellent (ICC>0.960 and CoV<0.71%). The Bland-Altman plots showed high agreement between the OLCR-based and SS-OCT-based devices for AL, CCT, AQD, ACD, Km and LT, with narrow 95% limit of agreements (LoAs) (-0.08 mm to 0.06 mm, -15.91 μm to -1.01 μm, -0.09 mm to 0.09 mm, -0.09 mm to 0.08 mm, -0.47 D to 0.35 D, -0.05 mm to 0.16 mm, respectively) and moderate agreement for CD (95% LoA: -0.67 mm to -0.01 mm). Conclusions The new Suoer SW-9000 μm Plus biometer showed excellent repeatability and reproducibility. All the parameters obtained by this biometer were similar to those measured by SS-OCT-based biometer. [ABSTRACT FROM AUTHOR]

Purpose To quantitate lens nuclear opacity using long-range swept-source optical coherence tomography (SS-OCT) images and to evaluate the correlation of this method to Lens Opacities Classification System III (LOCS III) and a Scheimpflug imaging-based grading system (Pentacam Nuclear Stage function; PNS). Methods This study enrolled 120 participants (120 eyes) with age-related nuclear cataracts. The best-corrected visual acuity (BCVA), LOCS III nuclear opalescence (NO) and nuclear colour (NC) were obtained. The nuclear density measured using PNS function (NDPNS) was recorded. Three successive series of long-range SS-OCT images were captured, and the nuclear region was analysed using ImageJ (NIH, Bethesda, Maryland, USA) to generate SS-OCT imagebased nuclear density (NDSS-OCT). The repeatability of NDSS-OCT measurement was evaluated using withinsubject coefficient of variation (CVw) and intraclass correlation coefficient (ICC). Correlations of NDSS-OCT with NO and NC, BCVA and NDPNS were analysed. According to the integrity of nucleus imaged by Pentacam, patients were divided into two groups, and the parameters were compared between groups. Results The CVw and ICC for NDSS-OCT measurement were 1.5 % and 0.994, respectively. The NDSS-OCT significantly correlated with NO (r=0.831), NC (r=0.873), BCVA (r=0.655) and NDPNS (r=0.891). The NDSS-OCT, NO and NC, and BCVA were significantly different between the two groups. Conclusion Lens nuclear opacity quantitation using long-range SS-OCT images was repeatable and correlated well with LOCS III and PNS function. The Scheimpflug principle had a limitation in imaging dense nucleus. Long-range SS-OCT seems more promising for objectively and quantitatively assessing lens nuclear opacity. [ABSTRACT FROM AUTHOR]

Objective To assess the repeatability and agreement between the Aladdin and Lenstar biometers. Methods Three consecutive measurements of the right eye of 102 subjects were acquired by the Aladdin (V.1.1.3) and the Lenstar (V.1.0.3), respectively, with a random order of which biometer to use first. Parameters compared included axial length (AL), anterior chamber depth (ACD), flat keratometry (Kf ), steep keratometry (Ks), mean keratometry (Km), J0, J45 and white-to-white (WTW) distance. Intraocular lens (IOL) power formulas included SRK/T (Sanders-Retzlaff-Kraff/Theoretical), Holladay 1, Hoffer Q and Haigis. Repeatability (Sr), repeatability limit (r) and Bland-Altman limits of agreement (LoA) were calculated. Results Sr was marginally better with the Lenstar for AL (0.02 mm), ACD (0.02 mm) and WTW distance (0.07 mm), but Sr was marginally better with the Aladdin for Kf (0.10 dioptre (D)), J0 (0.07 D) and J45 (0.06 D). In terms of agreement, the mean difference was small and non-statistically significant between the two devices for ACD, Ks and J45. The mean difference for Kf, Km, J0 and WTW distance were all statistically significantly lower with the Aladdin than the Lenstar for the exception of WTW distance. The Bland-Altman LoA displayed narrow ranges implying good agreement with the exception for WTW distance. For IOL formulas, the mean difference was very small and not statistically significantly different. The LoA were narrow (within 0.50 D), implying acceptable use of each device interchangeably. Conclusions High levels of repeatability and agreement were found between the Aladdin and Lenstar suggesting that the devices may be used interchangeably in normal eyes with refractive error. [ABSTRACT FROM AUTHOR]

Objective To validate a visual ability instrument for school-aged children with visual impairment in China by translating, culturally adopting and Rasch scaling the Cardiff Visual Ability Questionnaire for Children (CVAQC). Methods The 25-item CVAQC was translated into Mandarin using a standard protocol. The translated version (CVAQC-CN) was subjected to cognitive testing to ensure a proper cultural adaptation of its content. Then, the CVAQC-CN was interviewer-administered to 114 school-aged children and young people with visual impairment. Rasch analysis was carried out to assess its psychometric properties. The correlation between the CVAQC-CN visual ability scores and clinical measure of vision (visual acuity; VA and contrast sensitivity, CS) were assessed using Spearman'sr. Results Based on cultural adaptation exercise, cognitive testing, missing data and Rasch metrics-based iterative item removal, three items were removed from the original 25. The 22-item CVAQC-CN demonstrated excellent measurement precision (person separation index, 3.08), content validity (item separation, 10.09) and item reliability (0.99). Moreover, the CVAQC-CN was unidimensional and had no item bias. The person-item map indicated good targeting of item difficulty to person ability. The CVAQC-CN had moderate correlations between CS (-0.53, p<0.00001) and VA (0.726, p<0.00001), respectively, indicating its validity. Conclusions The 22-item CVAQC-CN is a psychometrically robust and valid instrument to measure visual ability in children with visual impairment in China. The instrument can be used as a clinical and research outcome measure to assess the change in visual ability after low vision rehabilitation intervention. [ABSTRACT FROM AUTHOR]

Objective To evaluate the precision of the measurements in healthy subjects obtained with a new optical biometer (OA-2000, Tomey, Nagoya, Japan) using swept-source optical coherence tomography (SS-OCT) and compare these measurements with those provided by the IOLMaster v5.4 (Carl Zeiss Meditec AG, Jena, Germany) using partial coherence interferometry (PCI). Methods Axial length (AL), keratometry (K) over 2.5 mm and 3.0 mm diameters, anterior chamber depth (ACD) (corneal epithelium to lens), lens thickness (LT), central corneal thickness and corneal diameter (CD) were measured with SS-OCT by two experienced operators. Intraobserver repeatability and interobserver reproducibility were assessed. AL, ACD, K and CD were also measured with PCI for agreement analysis using Bland-Altman plots. Results Sixty-five eyes of 65 normal subjects were enrolled in the prospective study. The SS-OCT measurements revealed high repeatability and reproducibility with low test-retest repeatability, low within-subject coefficient of variation (CoV) and high intraclass correlation coefficients. Bland-Altman analysis showed narrow 95% limits of agreement for most parameters indicating excellent agreement for AL (-0.05 mm to 0.07 mm), K values both at 2.5 mm (-0.42 D to 0.20 D) and 3.0 mm (-0.42 D to 0.08 D) and ACD (-0.19 mm to 0.22 mm) except for the CD (-1.11 mm to -0.01 mm). Conclusions The repeatability and reproducibility of SS-OCT were excellent for all parameters including AL, K, ACD, LT and CD values. High agreement was shown between SS-OCT and PCI for most biometrical parameters. [ABSTRACT FROM AUTHOR]

Purpose Diabetic retinopathy (DR) is one of the secondary microvascular complications of type 2 diabetes mellitus. Persistent inflammation and impaired neovascularisation may be important contributors to the development of DR. A recent study showed that toll-like receptor 4 (TLR4) polymorphisms were associated with DR. The present study was designed to determine whether single-nucleotide polymorphisms (SNPs) in the TLR4 gene were associated with DR in a Chinese Han population. Materials and methods Three SNPs (rs10759931, rs1927911 and rs1927914) in the TLR4 gene were chosen as candidate SNPs. Genomic DNA from type 2 diabetes patients and healthy controls were genotyped for the above-mentioned genetic variations through the use of PCR restriction fragment length polymorphism assay. Data were analysed by χ2 analysis. Results The results showed that the three analysed polymorphisms in the TLR4 gene were in Hardy- Weinberg equilibrium, both in the patients and in the controls. In the type 2 diabetes group, a significantly higher frequency of the C allele of rs1927914 was observed in patients with type 2 diabetes than that in controls. The result showed that the frequencies of the TT genotype and the T allele of rs1927914 were significantly decreased in patients with type 2 diabetes. Significantly increased frequencies of the CC genotype and the C allele of rs1927911 were observed in patients with type 2 diabetes. In the DR group, the C allele of rs1927914 was significantly increased in the DR group compared with that of the control. The frequencies of the CC genotype and the C allele of rs1927911 tended to be higher in patients with DR than in the healthy controls. However, no difference was found when the Bonferroni correction was applied. No difference was detected between patients and controls with regard to all haplotypes. Conclusions This study suggested that rs1927914 and rs1927911 were associated with type 2 diabetes mellitus and that rs1927914 was associated with susceptibility to DR in a Han Chinese population. [ABSTRACT FROM AUTHOR]

Objective To assess the reliability of ocular component measurements with a new optical biometry device (ALScan; Nidek) and compare these measurements with those of the IOLMaster (Carl Zeiss Meditec) in patients with cataract. Methods Sixty-eight cataractous eyes of 68 patients were included in the prospective study. To assess ALScan repeatability and reproducibility, central corneal thickness, anterior chamber depth (ACD), keratometry (K) over 2.4 mm and 3.3 mm diameter, axial length (AL), white to white (WTW), and pupil distance (PD) values were measured by two operators. ACD, K, AL and WTW were also measured with the IOLMaster to investigate the level of agreement. Calculations of intraocular lens (IOL) power were compared between the two devices. Results AL-Scan measurements were highly repeatable and reproducible, except for WTW and PD. Bland- Altman analysis showed good agreement between devices for AL, ACD and most K values. Compared with the IOLMaster, AL-Scan-derived K values using a diameter of 2.4 mm showed a narrower 95% limit of agreement (LoA) than those obtained with a diameter of 3.3 mm. However, poor agreement of WTW measurements was found. The 95% LoAs between devices for IOL calculations were smaller when based on AL-Scan K measurements using a diameter of 2.4 mm rather than 3.3 mm. Conclusions The repeatability and reproducibility of AL-Scan was excellent for all parameters, except WTW and PD. Excluding WTW, good agreement was found between the AL-Scan and IOLMaster. The 2.4-mm diameter K value may be the most reliable choice for calculation of IOL power with the AL-Scan. [ABSTRACT FROM AUTHOR]