ABSTRACT
Background: Welding emits harmful rays to the eyes. We evaluate and compare the UV, blue light and IR transmittance characteristics of some currently available welding safety protectors with ANSI Z87.1 criteria
Materials and Methods: Three type of welding safety protectors [three of each type] have been evaluated for spectral transmittance. One-sample T-test was performed to establish is there a statistically significant difference between the standard criteria and UV, blue and IR regions for the welding protectors [alpha=0.05]
Results: In ultraviolet [UV] [far and near] region, two types of the tested protectors [P1, P2] transmitted lower than the maximum allowable value specified in the standard [P<0.001]. In infrared [IR] spectrum only one type [P3] transmitted lower than the maximum allowable value specified in the standard [P<0.001]. In blue light region, all of the tested protectors transmitted lower than the maximum allowable value specified in the standard [P<0.001]
Conclusion: Although all of the tested glasses could meet some parts of the criteria, but none of them could meet the complete spectral transmittance requirements of ANSI Z87.1
Subject(s)
Ultraviolet Rays , Infrared Rays , Safety Management , Eye Protective DevicesABSTRACT
Taking visual acuity is an important part of an eye routine examination. This study was conducted to compare visual acuity measured using an Iranian digital tumbling E chart with visual acuity measured using an Italian digital tumbling E chart as a familiar foreign chart. This study was carried out on 200 participants [400 eyes; healthy n=40, glaucoma n=40, retinal disorders n=40, post lasik n=40, corneal n=40] with mean age 44.28 years. Visual acuity of both eyes in half of the subjects [n=100, n=20 from each group] was first measured using the Italian digital chart and then measured using Iranian digital chart. Visual acuity of the rest of subjects [n=100, n=200 from each group] was first measured using the Iranian digital chart and then measured using the Italian digital chart. Measured visual acuities were recorded in logMAR notation. Mean of the Iranian and Italian Tumbling E chart is 0.280 +/- 0.012 and 0.277 +/- 0.012, respectively. Paired t-test used to evaluate the mean difference between two groups [p=0.721] indicated that there was no statistically significant difference between means of the two tests. Spearman correlation coefficient for the results of both tests was 0.942 [p<0.001], which was statistically significant and could be categorized as a strong positive correlation. The two digital Tumbling E charts acted similarly at different levels of acuity in different disorders. However, the Iranian chart requires a more accurate design for optotypes of the lower acuity lines in order to obtain more accurate measurement of visual acuities in healthy subjects
Subject(s)
Humans , Female , Male , EyeABSTRACT
Background: Artificial tears have been among the first line of therapy in management of Dry Eye Syndrome [DES]. This study was conducted to compare a local artificial tear with an imported one in reduction of DES. This comparison would help to evaluate the cost and benefits of each drop in the proper management of DES.
Materials and Methods: In this double-blind randomized clinical trial study, a total 65 students meeting our inclusion criteria for DES entered the study. The OSDI questionnaire, TBUT, corneal and conjunctival staining and Schirmer test, were performed. The patients were divided into two groups by block randomization. Group 1 received first drop and group 2 received second drop. Both groups were instructed to use the drops 4 times a day for 14 days. The same tests were performed by the same examiner who was blind to the treatment type after two weeks. Repeated measured ANOVA was used to analyze the data.
Results: A total of 58 patients completed the study. In both groups, after the intervention, the OSDI scores [P<0.001], TBUT score [P=0.041], corneal [P<0.001] and conjunctival staining scores [P<0.001] showed improvement in compare to those before the intervention. However, the Schirmer test score did not show significantly difference before and after intervention. In comparing two groups the OSDI scores, the TBUT score, the corneal and conjunctival staining scores and the Schirmer scores did not show statistically significant difference.
Conclusion: The two artificial tears equally reduced the symptoms and signs of DES in two weeks.
ABSTRACT
Long-time erexposure to ultraviolet radiations can lead to various skin and ocular diseases. UV-blocking contact lenses due to their properties against ultraviolet radiations can protect eyes. The present study aimed to compare between ultraviolet and visible light rays transmission through soft contact lenses available in Iran. In this cross-sectional study, 6 types of contact lenses [Avaira, Biofinity, Acuvue 2, Acuvue Oasys, Ultra Wave, and Specialy S55] were purchased from reputable companies of the country, and were evaluated in terms of transmission of ultraviolet and visible light according to U.S. Food and Drug Administration of [FDA] criteria. To test the samples, a calibrated spectral transmittance-meter was used, which had the ability of evaluation of samples at wavelengths of ultraviolet type B, type A, and visible light. The data were analyzed by ANOVA and post hoc Tukey tests. The significance level was considered to be p >/= 0.05. In this study, none of the lenses were eligible for blocking UV radiation. Among the UV-blocking soft lenses, the Acuvue Oasys had the best performance, with a transmittance of less than 4% of UV-B and less than 45% of UV-A. All of the lenses decreased the transmittance of visible light about 4%. Considering that all of the studied contact lenses can protect eyes against UV radiation compared to other lenses, but for protection against harmful sunlight, standard sunglasses and an appropriate hat should be used together with even the best UV-blocking contact lenses
ABSTRACT
Wearing spectacles is the most common approach in correcting the refractive errors worldwide. Due to harmful effects of overexposure to solar ultraviolet radiations, the usage of multi-layer coatings in ophthalmic lenses has recently been increased. These lenses can reduce the reflections and hence increase the transmission of visible light; they can also decrease the transmission of ultraviolet rays. This study aims to compare the transmission of ultraviolet [A and B] and visible rays through coated and uncoated prescriptive ophthalmic plastic lenses. In this study, 39 minus non-photochromic multi-coated white plastic single-vision lenses; 9 similar lenses but without any coatings were assessed by spectral transmittancemeter for evaluation of the transmission of visible and ultraviolet rays. The transmission of visible light was 97.9% +/- 1.07% for coated lenses and 93.5% +/- 0.54% for lenses without coating. Ultraviolet-A transmission was 12.15% +/- 8.02% for coated lenses compared to 66.27% +/- 23.92% in lenses without coating. The transmission of ultraviolet-B rays was 1.21% +/- 0.4% and 23.0% +/- 15.97% for lenses with and without coatings, respectively. The transmission of visible light was significantly higher in multi-coated lenses compared to uncoated samples; whereas the transmissions of ultraviolet rays in multi-coated lenses were significantly lower than uncoated ones. Therefore, it is recommended that, except for particular cases, prescribed lenses be equipped with this multilayer coating
ABSTRACT
Dry eye is the major contributor to computer vision syndrome. The reductions in the blink rate and amplitude have been considered as the possible mechanisms leading to this condition. The purpose of this study is to evaluate the changes in the lower tear meniscus heights and areas in the computer reading task, in dry eye subjects, with and without soft contact lenses. In this quasi-experimental study, 39 subjects [with mean age of 21.2 +/- 2.4 years], with dry eye, were enrolled. The lower tear meniscus height and area [TMH, TMA] of the right eye was captured by Spectral Optical Coherence Tomography before and after 45 minutes of reading task behind desktop 17" Cathode Ray Tube monitors. The same procedure was performed after the insertion of the hydrogel soft contact lenses with 58% water content. The results of TMHs, TMAs were analyzed with a repeated measures analysis of variance [ANOVA] with two within-subject factors.: The mean +/- standard error of TMH and TMA pre and post computer tasks were 283.6+/- 25.4 micro m, 0.029+/-0.005 mm2, 297.6+/-20.7 micro m , 0.036 +/- 0.005 mm2 respectively. After contact lens insertion, the mean TMH and TMA pre and post computer task were 231.6 +/- 10.6 micro m, 0.020+/-0.0019 mm2, 213.0+/-9.0 micro m, 0.018 +/- 0.0011 mm2, respectively. Repeated measures analysis of variance showed that the changes in TMH [P=0.86] and TMA [P=0.37] after computer task, were not statistically significant, while the insertion of the soft contact lens had reduced the TMH and TMA significantly [P<0.001 for both]. After 45 minutes of reading task behind desktop monitors, the tear volume has not changed, with and without high water SCLs. A reduction in tear volume might be expected with longer duration of computer task or at late hours of the day. The creation of a more stable tear film should be considered in the management strategies for shorter duration of work behind desktop monitors
ABSTRACT
The aim of this study was to compare the effect of post space preparation with Gates Glidden drills or hand files on the sealing ability of gutta-percha or Resilon obturation materials. One-hundred and four single-rooted human teeth were instrumented and divided into four experimental groups [n=21 each] and two groups of positive and negative control [n=10]. Forty-two roots of experimental groups were obturated with gutta-percha and Dorifill sealer; and 42 roots with Resilon/Epiphany self-etch using lateral compaction technique. Each gutta-percha or Resilon group was divided into two subgroups [n=21] and post-space prepared with either Gates Glidden drills or hand files and chloroform. After post space preparation, 5 mm of apical gutta-percha or Resilon was left intact. The whole system was sterilized with gamma-rays. Saliva leakage was tested using a split-chamber model. Specimens were monitored every 24 hours for 30 days. The data were analyzed using log-rank test and Cox regression analysis. There were no significant differences between the sealing ability of gutta-percha and Resilon. Furthermore, no significant difference was found between two different methods of post space preparation [P>0.05]. Under the limitations of this ex vivo study, there were no significant differences between the sealing ability of Resilon and gutta-percha after post space preparation using Gates Glidden drills or hand files with the aid of chloroform