THE LIGHT-DOSIMETER – A NEW DEVICE TO HELP ADVANCE RESEARCH ON THE NON-VISUAL RESPONSES TO LIGHT

Research on the non-visual responses to light under real-world conditions has been hindered by the lack of suitable measuring devices. Here, we present a novel, portable and miniaturised light-dosimeter attached to a spectacle frame, taking measurements in the near-corneal plane. The recorded data is processed with the help of the custom-made software package Lido Studio. In addition to commonly used metrics such as illuminance and correlated colour temperature (CCT), it also provides metrics standardised in CIE S 026:2018. Data can be analysed directly in Lido Studio or exported as a PDF report or a comma-separated values (CSV) file for further in-depth time-series analyses. The Federal Institute of Metrology (METAS) optics laboratory (Bern-Wabern, Switzerland) assessed the light-dosimeter’s spectral and geometric properties. Subsequentially, the team at the Centre for Chronobiology (Basel, Switzerland) confirmed that measurements performed with a light-dosimeter were comparable to those from a commercial spectroradiometer.

Alternative Flicker Glass: a New Anti-suppression Approach to the Treatment of Anisometropic Amblyopia

Introduction: Amlyopia always presents with monocular and binocular dysfunction. In this study, we aim to investage the efficacy of alternative occlusion using liquid crystal glasses versus continuous occlusion therapy using traditional patches for treating amblyopia. Methods: Eligible subjects with anisometropic amblyopia were randomized into two groups: alternative flicker glass (AFG) or patching group. In the AFG group, subjects were instructed to wear the flicker glasses for 1 hour a day. The AFG is a lightweight spectacle frame with liquid crystal lenses that provide direct square-wave alternating occlusion, which were pre-programmed at temporal frequency of 7Hz. In the patching group, the patients were prescribed to wear traditional patches for 2 hours a day. The best corrected visual acuity (BCVA), contrast sensitivity function (CSF) and stereoacuity were measured at the baseline, 3 and 12 weeks. Results: In this pilot study, a total of forty children were recruited, with twenty in the AFG group. Mean BCVA improved by 0.17±0.14logMAR (95% CI=0.10 to 0.23) in the AFG group, while 0.18±0.18logMAR (95% CI=0.09 to 0.26) in the patching group from baseline to 12 weeks. The improvement of BCVA in both groups were significant (both P＜0.01), while no significant difference between the groups (P=0.82). The CSF of both low and high spatial frequencies exhibited significant improvement at 12 weeks in the AFG group (P＜0.01, respectively), while just have a significant improvement at low spatial frequency in the patching group (P＜0.01). The stereoacuity significantly improved by 504.00±848.00 (95% CI= -900.88 to -107.12) arc seconds in the AFG group (P＜0.05), while 263.50± 639.55 (95% CI=-562.82 to 35.82) arc seconds in the patching group (P＞0.05). Conclusion: Alternative flicker glass was effective in improving both monocular and binocular function, which was most likely achieved by reducing the suppression and promoting binocular fusion. This therapy exhibited promise as an alternative method for amblyopia treatment.

Survey of Interpupillary Distance in Egyptian People

Purpose The aim of this study was to report normative values and ranges of interpupillary distance (IPD) in Egyptian people. Methods This study included 83 healthy subjects; 41 males and 42 females presented with refractive errors to the outpatient clinic of Elshiekh-Zaid specialized hospital in Cairo. After complete ophthalmic evaluation, far IPD measurements were performed using an autorefractometer (Speedy-1, Nikon, Japan), graded ruler (401 A5 stainless hardened, Japan), spectacle frame with two cross-wire lenses (universal trial frame, Carejoy, China). Near IPD measurements were performed using the graded ruler and the spectacle frame. Results Mean age of the study population was 35.1±8.0 years (range 20-50). The mean IPD for far was found to be 64.1±3.7 mm (range 56-72) by autorefractometer (p < 0.001), 63.9±3.7 mm (range 56-72) by PD ruler (p < 0.001), and 62.9±3.7 mm (range 55-71) by frame (p < 0.001). The mean IPD for near was found to be 61.9±3.7 mm (range 54-70) by PD ruler (p < 0.001), and 61.0±3.6 mm (range 53-68) by frame (p < 0.001). The mean IPD value was observed to be significantly higher among males (p < 0.001). Far and near IPD difference by PD ruler was 2.0±0.5 mm (p < 0.001) and by frame was 1.9±0.6 mm (p < 0.001). Conclusion The current study showed normative data on far IPD and near IPD by different methods in Egyptian people. Our study showed that sex and age had significant effects on IPD. Knowledge of normal values in this population may be useful in studying orbito-cranial growth patterns, syndrome diagnosis, surgical management of cranio-facial deformities and trauma, and manufactures of optical frames and lenses.

Microstructures and Properties of Ti-25Nb-15Zr Alloy for Spectacle Frame

Mechanical properties and microstructures of a new β Ti-25Nb-15Zr alloy for spectacle frame were studied. The results show that the optimum cold rotary swaging reduction of the alloy is between 50% and 70%. The wire of 3mm in diameter exhibited an equiaxed microstructure consisting only β single phase and fine grain with less than 10mm size when the alloy is heat treated at 1003K for 1.8Ks. While it has good shape memory property, and the maximum complete recovery strain was up to 3% at room temperature. At the same time, the flattened frame legs were solution-treated to improve their elastic behavior, so the residual strain was completely or partly recovered due to transformation of the microstructure.