Tribal Odisha Eye Disease Study # 4: Accuracy and utility of photorefraction for refractive error correction in tribal Odisha (India) school screening.

Purpose: To compare the photorefraction system (Welch Allyn Spot™) performance with subjective refraction in school sight program in one Odisha (India) tribal district. Methods: In a cross-sectional study school students, aged 5-15 years, referred after the preliminary screening by trained school teachers received photoscreening and subjective correction. The photoscreener was compared to subjective refraction in the range of +2D to -7.5D. Statistical analysis included Friedman nonparametric test, Wilcoxon signed-rank test, linear regression, and Bland-Altman plotting. Results: The photoscreener was used in 5990 children. This analysis included 443 children (187 males, 256 females, and the mean age was 12.43 ± 2.5 years) who received both photorefraction and subjective correction, and vision improved to 6/6 in either eye. The median spherical equivalent (SE) with spot photorefraction was 0.00 D (minimum -5.0D; maximum +1.6 D), and with subjective correction was 0.00D (minimum -6.00 D; maximum +1.5 D). The difference in the SE between the two methods was statistically significant (P < 0.001) using Friedman nonparametric test; it was not significant for J 45 and J 180 (P = 0.39 and P = 0.17, respectively). There was a good correlation in linear regression analysis (R2 = 0.84) and Bland-Altman showed a good agreement between photorefraction and subjective correction in the tested range. Conclusion: Photorefraction may be recommended for autorefraction in school screening with reasonable accuracy if verified with a satisfactory subjective correction. The added advantages include its speed, need of less expensive eye care personnel, ability to refract both eyes together, and examination possibility in the native surrounding.

Synthesis of a bile acid-based click-macrocycle and its application in selective recognition of chloride ion.

A novel method for the synthesis of a bile acid-based macrocycle has been developed using click chemistry. The 1,2,3-triazolium derivative of the macrocycle shows remarkable selectivity in binding of chloride ion.

Evaluation of central corneal thickness measurement with RTVue spectral domain optical coherence tomography in normal subjects.

PURPOSE: To determine (1) repeatability of central corneal thickness (CCT) measurements by spectral domain optical coherence tomography (RTVue; Optovue, Inc, Fremont, CA) and (2) agreement between CCT measurements by RTVue and those by ultrasonic pachymetry, Orbscan, and anterior segment optical coherence tomography (ASOCT). METHODS: In a prospective observational study, 2 cohorts of normal subjects were recruited. In the first cohort (51 subjects), 5 measurements of CCT were obtained by RTVue during the same visit to determine the repeatability. In the second cohort (65 subjects), CCT measurements were obtained by RTVue, ultrasonic pachymetry, Orbscan, and ASOCT during the same visit to determine the agreement among these instruments. Repeatability was assessed by intraclass correlation coefficient (ICC), within-subject standard deviation, coefficient of repeatability, and within-subject coefficient of variation. Agreement was assessed by ICC and Bland and Altman plots. RESULTS: Repeatability of CCT measurements by RTVue as assessed by ICC, within-subject standard deviation, coefficient of repeatability, and within-subject coefficient of variation was 0.99 (0.99-0.99), 2.2 (1.9-2.5), 4.2 µm (3.6-4.8), and 0.4% (0.3-0.5), respectively. The average CCT by RTVue (529 µm) was comparable to that by ultrasonic pachymetry (539 µm; P = 0.15), Orbscan (536 µm; P = 0.54), and ASOCT (526 µm; P = 0.77). The 95% limits of agreement on Bland and Altman plots ranged from 20 µm (between RTVue and ASOCT) to 33 µm (between RTVue and Orbscan). CONCLUSIONS: CCT measurements by RTVue have an excellent repeatability. Although CCT measurements by RTVue are comparable to that by ultrasonic pachymetry, Orbscan, and ASOCT, the difference between instruments can be significant depending on the clinical situation considered.

Predictors of normal optic nerve head, retinal nerve fiber layer, and macular parameters measured by spectral domain optical coherence tomography.

PURPOSE: To evaluate the effects of signal strength, age, sex, optic disc size, and axial length on the normal optic nerve head (ONH), retinal nerve fiber layer (RNFL), and macular measurements with spectral domain optical coherence tomography (SD-OCT). METHODS: In an observational, cross-sectional study, 119 eyes of 60 normal subjects of Indian origin underwent ONH, RNFL, and macular imaging with SD-OCT during the same visit. Linear mixed-modeling methods were used to evaluate the effects of signal strength, age, sex, optic disc area, and axial length on ONH, RNFL, and macular measurements. RESULTS: ONH rim measurements increased and cup measurements decreased with increasing signal strengths. For a 10-unit increase in signal strength, total rim area increased by a mean of 0.1 mm(2). ONH measurements also increased with increasing optic disc size. Rim measurements decreased and cup measurements increased with increasing axial length. None of the predictors influenced RNFL measurements. Macular inner retinal thickness decreased by a mean of 1.7 µm and macular full retinal thickness decreased by an average of 3.4 µm for every decade's increase in age. Sex did not influence any of the measurements. CONCLUSIONS: Signal strength, optic disc size, and axial length had a significant effect on ONH measurements, whereas age had a significant effect on macular measurements. None of the predictors evaluated influenced the RNFL measurements. These predictors should be considered when evaluating change in the structural measurements in glaucoma over time.

Synthesis of click bile acid polymers and their application in stabilization of silver nanoparticles showing iodide sensing property.

A novel method for the synthesis of bile-acid-based polymers has been developed using click chemistry. These 1,2,3-triazole-containing polymers have been found to stabilize silver nanoparticles that show selective colorimetric sensing for iodide ion.

Anion recognition by 1,2,3-triazolium receptors: application of click chemistry in anion recognition.

Cyclic and acyclic bile acid-based 1,2,3-triazolium receptors which show remarkable ability to recognize anions through C-H...X- hydrogen bond interactions have been synthesized using click chemistry.