Refractive Glass Research Articles

Scope of Ayurveda treatment in Myopia: A systematic review of current trends

Abstract BACKGROUND: Though myopia is an ophthalmic refractive error disease that is commonly managed with refractive glasses and advanced surgeries, it still remains a refractive condition of great concern. Patients often resort to alternate methods to rectify or manage myopia and prevention of its progression. Ayurveda refers to myopia as Timira (errors of refraction), characterized by disturbances in vision; hence, it is considered to be a part of Drishtigata Rogas (eyesight disorders). According to the Ayurvedic perspective, myopia is primarily a result of vitiated Doshas, particularly the imbalance of the Vata Dosha, which impairs the eye muscles and lens, resulting in the inability to focus on distant objects. MATERIALS AND METHODS: This review adhered to the 2020 PRISMA guidelines and involved a comprehensive search of PubMed, Scopus, and UGC-CARE-listed Ayurveda journals from January 2000 to September 2023. The focus was on randomized controlled trials examining Ayurvedic interventions, including topical and oral therapies, for managing myopia or Timira. The search aimed to identify all relevant studies published within the specified timeframe. The Cochrane risk-of-bias tool for randomized trials (RoB 2) was utilized to evaluate the risk of bias. RESULTS: A total of six publications in credible journals were found and analyzed, which revealed that practices such as Netra Tarpana (retaining of medicated ghee over the eye), Nasya (medication through the nasal route), Anjana (collyrium), use of Triphala, Ayurvedic formulations, yoga, and specific eye exercises can enhance the strength of ocular muscles, promote better nourishment of ocular tissues, and foster overall eye health. CONCLUSION: By implementing prophylactic measures, followed by therapeutic and systemic therapies, myopia can be controlled with a multidimensional approach, but due to limited sources of evidence, the certainty can only be proven after extensive clinical trials.

Multi-component 20La2O3–20TiO2–20Nb2O5-20(Al2O3/ZrO2)-20(ZrO2/Ta2O5) glasses with ultra-high refractive index and mechanical properties inspired by high-entropy design

The highly refractive glasses with excellent mechanical properties (hardness, Young's modulus, and fracture toughness) are highly desired for the lenses used in small optical devices. In this study, a series of five-primary-component 20La2O3–20TiO2–20Nb2O5-20(Al2O3/ZrO2)-20(ZrO2/Ta2O5) (LTNAZ, LTNAT, LTNZT) glasses were designed by using high-entropy strategy and successfully elaborated through a containerless melting-solidification process. The highest refractive index (nd) of the glasses reach up to 2.25. The maximum vickers hardness (HV), Young's modulus (E), and indentation fracture toughness (KIFT) are 10.74 GPa, 157.5 GPa, and 1.23 MPa m0.5 respectively. The glasses exhibit good glass forming ability with kinetic window (ΔT) ranging from 80 to 116 °C. The excellent comprehensive performances of the glasses are attributed to the high electronic polarizability and dissociation energy, as well as the synergistic effect of multiple components in the high-entropy effect. The glasses will be promising host materials for optical applications such as digital product lenses, endoscopes and mini size lasers.

Determination Of Optical Constant of a Clear Glass Material for Accurate Daylighting and Solar Heat Gain Assessment Using Spectrophotometer Measurements

Many qualities make glass attractive, as it is transparent, chemically inert, environmentally friendly, sustainable, strong, easily available and relatively cheap. Recently, many researchers have been interested in designing the buildings to get the benefit from daylight inside, which saves a lot of building consumption for artificial lighting, which gives visual and thermal comfort and also contributes to reducing costs. The complex refractive index of glass is a very crucial concept because it determines not only how much light is reflected and transmitted, but also its angle of refraction in glass. The optical constants of glass material are very useful for determining its radiative properties, as well as for selecting the appropriate thin-film coatings on a glass substrate. The objective of this study is to calculate the real part (n) and the imaginary part (k) of the complex refractive index of a clear glass material using a simple method based on the reflectivity and transmissivity measurements. In this study, the parts n and k are derived from the equations of the reflectivity at near zero incidence and transmissivity at normal incidence by using Shimadzu IR-70 Spectrophotometer and Cary 5E Spectrophotometer apparatuses. The real and the imaginary parts of the complex refractive index of the glass sample obtained in the present study are in very good agreement with Rubin’s data. Although, a direct comparison between different samples is not possible, due to the difference in manufacturing process and material composition.

Imaging model and vision measurement method considering refraction effect of flat glass windows in tunnel construction

Vision measurement has become an indispensable technology in tunnel construction. However, the harsh construction environment necessitates the provision of a certain thickness of flat glass windows to protect the vision system. This, in turn, leads to an obvious refraction effect, rendering the pinhole model and traditional vision measurement methods inadequate. As such, this paper offers a comprehensive solution to this problem. Firstly, the imaging model under the refraction of flat glass is shown based on the virtual camera and virtual space point, respectively. Secondly, a three-parameter calibration method for flat glass was proposed, which could determine the refractive index, unit normal vector, and light path normal distance. A practical dynamic interval constraint was introduced to address the failure of the epipolar constraint in refraction image pairs. Lastly, a new binocular disparity method is presented to avoid the impact of refraction distortion on the solution accuracy of three-dimensional coordinates. Effectiveness experiments are conducted, showing a refractive index relative error within ±1%, a miniaturized and efficient dynamic interval constraint, a maximum reconstruction error of 0.120 mm, and a maximum measurement error of only 0.093 mm. A series of stability experiments are also performed under different target attitudes, glass attitudes, working distances, and pollution conditions. The results demonstrate the robustness of the proposed solution. Although the scheme is developed for the vision system in harsh tunnel construction environments, it can serve as a reference for any vision measurement applications under glass protection windows.

Decorative effect of light refraction in glass

Decorative effect of light refraction in glass

Distribution Analysis of Refraction Defects in Prescriptions in Terms of Opticians: the Case of Karaman Province

The aim of this study is to analyze and evaluate refraction errors in prescriptions written in foundation and state hospitals in Karaman province. 213 people who applied to an ophthalmologist in the province of Karaman and were given prescriptions were included in the study. Of the 213 people included in the study; 126 (59.15%) are women, 87 (40.85%) are men. Near and far eyeglasses data on prescriptions were divided into 7 groups as simple myopia, simple hyperopia, simple myopic astigmatism, simple hyperopia astigmatism, composite myopic astigmatism, compound hyperopia astigmatism, and mixed astigmatism. In the near-eyeglass right glass refraction defects analysis in the research; simple hypermetropia was the most common with 22.06%, while the least common simple myopic astigmatism was detected with 0.94%. In the near eyeglass left eyeglass refraction defects analysis; while mixed astigmatism was the most common with 22.53%, it was determined that it was the least seen simple myopic astigmatism with 0.47%. In the far eyeglass right glass refraction defects analysis; compound myopic astigmatism was the most common with 30.98%, and the least common was simple hypermetropic astigmatism with 2.35%. In the far eyeglass left eyeglass refraction defects analysis; compound myopic astigmatism was the most common with 29.11%, while the least common was simple hypermetropic astigmatism with 2.35%. The research is important due to it is the first study to examine the refractive error distribution in Karaman.

Local atomic structure of the high refractive index La2O3–Nb2O5–B2O3 glasses

High refractive glasses in the La2O3–Nb2O5–B2O3 (LNB) system were synthesized by the melt-quenching technique and correlations between their compositions and structural features were clarified. It was found that the refraction index of the LNB glasses is tunable from 1.71 to 1.98 by the variation of the Nb2O5 fraction from 5 to 30 mol%. The infrared spectroscopy analysis implies on the presence of three and four coordinated borate units, as well as six coordinated niobium atoms. The X-ray absorption (La L3-edge and Nb K-edge XANES and EXAFS) spectroscopy and total X-ray scattering results show that niobium atoms maintain octahedral oxygen coordination despite the wide variation of the Nb2O5 content, while average lanthanum coordination number is versatile and changes from ~8 to ~10. The interatomic distance values testify that the niobium octahedra in the glass network are connected only “by corners”. The stability of niobium local atomic structure implies that the main source of the changes in the optical properties of studied glasses is the variation of the Nb2O5 content. The deeper understanding of the local atomic structure of the high refractive index LNB glasses paves ways for the development of new glass wafers for cutting-edge augmented reality devices.

PENINGKATAN HASIL BELAJAR PRAKTIKUM FISIKA ‎DENGAN MODEL PEMBELAJARAN KOOPERATIF TIPE TEAM ‎ASSISTED INDIVIDUALIZATION (TAI)‎

This classroom action research was conducted with the aim of knowing the improvement of students' physics practicum learning outcomes on light wave material using the Team Assisted Individualization (TAI) type of cooperative learning model. The research subjects were students of class XI IPA.6 MAN 2 Kota Padang in the 2020/2021 academic year. The research was carried out in two cycles, each cycle consisting of planning, implementation, observation, and reflection stages. Cycle I was carried out on the practical material of parallel plan glass refraction and the second cycle on the practical material of the diffraction grating. Students' practicum activity data is extracted with Student Activity Observation Sheets, teacher practicum learning management data is extracted with Learning Management Observation Sheets, while students' practicum learning outcomes data are excavated using Formative Tests in the form of practice. The results showed that: (1) Cycle I involving students with high initial abilities obtained an average learning outcome of 78.56 and a percentage of completeness 41%; (2) Cycle II involving students with high initial abilities and being given material and skill reinforcement obtained an average learning outcome of 87.78 and a 95% completeness percentage; (3) The learning outcomes of students' physics practicum in the second cycle have increased from the first cycle, both on average and the percentage of completeness. In conclusion, the Team Assisted Individualization (TAI) learning model can improve students' physics practicum learning outcomes.

Efficient white light-emitting Mg21Ca4Na4(PO4)18: Dy3+, Tb3+, Eu3+ triple-doped glasses: a multipurpose glasses for WLEDs, solar cell efficiency enhancement, and smart windows applications

As a kind of lanthanide-activated luminescent materials, the development of rare-earth-activated luminescent glasses is one of the promising trends in the modern luminescence research. In the proposed work, Dy3+, Tb3+, Eu3+ activated/co-activated/triple-activated Mg21Ca4Na4(PO4)18 orthophosphate glasses have been prepared by melt quenching technique for the first time. XRD pattern of the proposed glass sample shows amorphous nature, but the most intense peak is get matched with the standard ICSD database of Mg21Ca4Na4(PO4)18 material. Vibrational feature of the proposed glass sample has been investigated using FTIR analysis. SEM and EDS confirm the morphology and elemental analysis of the as-prepared glass. Photoluminescence study of triple-activated Mg21Ca4Na4(PO4)18 glass sample shows multiple emission peaks under NUV excitations which covers complete white light emission. Other optical properties like UV–Vis DRS, the refractive index of the glass and molar refraction of glass sample were investigated. Moreover, this glass sample is crushed homogeneously and coated on solar cell using doctor blade method shows the efficiency of solar cell enhanced by 43.33% than the blank solar cell. These results of the proposed sample prove its worth in the WLEDs, solar cell efficiency enhancement, and smart windows applications.

High refractive index colorless glasses composed of titanium oxo-oligomers modified with phthalate ions

High refractive index colorless glasses composed of titanium oxo-oligomers modified with phthalate ions

Glass Refraction Distortion Object Detection via Abstract Features.

Glass reflection and refraction lead to missing and distorted object feature data, affecting the accuracy of object detection. In order to solve the above problems, this paper proposed a glass refraction distortion object detection via abstract features. The number of parameters of the algorithm is reduced by introducing skip connections and expansion modules with different expansion rates. The abstract feature information of the object is extracted by binary cross-entropy loss. Meanwhile, the abstract feature distance between the object domain and source domain is reduced by a loss function, which improves the accuracy of object detection under glass interference. To verify the effectiveness of the algorithm in this paper, the GRI dataset is produced and made public on GitHub. The algorithm of this paper is compared with the current state-of-the-art Deep Face, VGG Face, TBE-CNN, DA-GAN, PEN-3D, LMZMPM, and the average detection accuracy of our algorithm is 92.57% at the highest, and the number of parameters is only 5.13 M.

Geometrically Driven Underground Camera Modeling and Calibration With Coplanarity Constraints for a Boom-Type Roadheader

The conventional calibration methods based on a perspective camera model are not suitable for the underground camera with two-layer glasses, which is specially designed for explosion proof and dust removal in a coal mine. Underground camera modeling and calibration algorithms are urgently needed to improve the precision and reliability of underground visual measurement systems. This article presents a novel geometrically driven underground camera calibration algorithm for a boom-type roadheader. The underground camera model is established under coplanarity constraints, considering explicitly the impact of refraction triggered by the two-layer glasses and deriving the geometrical relationship of equivalent collinearity equations. On this basis, we perform parameters calibration based on a geometrically driven calibration model, which are 2D-2D correspondences between the image points and object coordinates of the planar target. A hybrid Levenberg-Marqurdt (LM) and particle swarm optimization (PSO) algorithm is further proposed in terms of the dynamic combination of the LM and PSO, which optimizes the underground camera calibration results by minimizing the error of the nonlinear underground camera model. The experimental results demonstrate that the pose errors caused by the two-layer glass refraction are well corrected by the proposed method. The accuracy of the cutting-head pose estimation has increased by 55.73%, meeting the requirements of underground excavations.

Study of ferroelectric nanocomposites based on P(VDF-TrFE) by scanning probe microscopy

Ceramic and polymer based nanocomponents combine the properties of their constituents, e.g. flexibility, elasticity, polymer reprocessability, hardness typical of glass, wear resistance and high light refraction index. This helps improving many properties of the materials in comparison with the source components. Since recently researchers have been manifesting interest to the properties of complex composite compounds. This is primarily caused by the unique properties of their structures as compared with conventional materials having homogeneous composition. Secondly, this interest is caused by the fact that these compounds may prove to be much cheaper than homogeneous structures provided the physical properties of the composite in a preset range of parameters (temperature, applied field frequency etc.) are identical to those of the respective homogeneous materials. For example, polyvinyl idenfluoride (PVDF) type ferroelectric polymers and copolymers on its basis have found wide application for functional elements of various electromechanic devices in advanced electronics due to their relatively good piezoelectric and pyroelectric properties. The strong random polarization and the formation of polar non-centrosymmetric crystals provide for the high piezoelectric and pyroelectric activity in these crystals. Scanning probe microscopy has been used for study of ferroelectric nanocomposites having different compositions. The matrix specimen for study of local polarization switching at a nanoscale level was vinyl idenfluoride and trifluoroethylene P(VDF-TrFE) copolymer possessing sufficiently high crystallinity. The composite fillers were barium titanate BaTiO 3 and deuterized triglycinsulfate DTGS ferroelectric powders and zirconate-titanate lead barium BPZT ceramic powder. We show these materials to show good promise for use in memory cells.

Visual Acuity, Intraocular Pressure, and Macular Thickness in Patients Undergoing Dialysis

Background: Chronic kidney disease (CKD) is a public health problem over all the world. CKD may also be defined by the presence of kidney damage or a reduced glomerular filtration rate (GFR), which is the best overall indicator or index of kidney function. CKD patients are usually treated using kidney dialysis (hemodialysis) that uses a blood filtration mechanism (HD). Several metabolic parameters, such as blood urea, sodium, potassium, and glucose levels, can alter during HD. Osmotic alterations in blood, aqueous and vitreous humor, and other extracellular fluids arise from these fluctuations. That also can affect visual acuity, intraocular pressure (IOP), and retinal thickness. Aim of the Study: To evaluate some of the ocular findings undergoing HD to keep prevent the loss of patient vision such as visual acuity (VA), intraocular pressure (IOP), central corneal thickness (CCT), central Foveal Thickness (CFT), retinal nerve fiber layer (RNFL). Patient& Methods: This is a cohort (prospective) design study. This study including Seventy nine patients divided into two groups the first group from one week to six month (9 femal & 18 males) another group over than six month (36 female & 16 male) the average age between (12 to 70 years). This research performed in the three places department of the eye in Al-Hussein hospital in Samawah city, Al-Haboby hospital, Al-Hussein hospital in Dhi Qar city finally in Al-Shaheed Gazy hospital and Baghdad teaching hospital in Baghdad. Examining Visual Acuity by Snellen chart & auto refractometer, IOP& CCT by (CT.1 Computerized Tonometer TOPCON), RNLF and Central Foveal Thickness by OCT (Carl ZEISS, TOPCON). The inclusion criteria were as follows: all the patients undergoing dialysis from one week to over six months. Exclusion criteria were as follows: the patients have diabetic, any patients have a hereditary disease or glaucoma history or laser therapy, or intraocular injection in the eye before dialysis, the patients have a problem in the eye before dialysis such as cataracts or opacity leads to does surgery, the patients who have a refractive error or wear glass had been also excluded. Result: Includes the results of seventy-nine patients (45 females and 34 males) with chronic kidney disease examined ocular findings before a session of dialysis divided into two groups based on their duration of dialysis. Group one with twenty-seven patients (9 female & 18 male) under dialysis from one week to six months with mean & standard deviation (3.2037, ± 1.89259), group tow with fifty tow patients (36 female & 16 male) under dialysis from the duration over than six months with mean & standard deviation (44.2308, ± 26.24367) respectively. Patients aged (12 to 70 years) had mean age & ± standard deviation (35.1481, ± 12.88918), (44.4038, ± 15.42249) for two groups respectively. Patients in two groups had IOP (Right eye), its mean & standard deviation (15, ± 2.34), (15.69, ± 2.56) for group one & group tow respectively. Also, patients had CCT (Right eye) with mean & standard deviation (5.3467E2, ± 39.00296), (5.2312E2, ± 30.44162) for group one & group tow respectively. Patients had CCT (Left) with mean & standard deviation (5.2878E2, ± 37.55748), (5.2179E2, ± 29.58957) for group one & group tow respectively. Patients in two groups had average thickness RNFL (Right eye) with mean & standard deviation (1.0604E2, ± 25.17551), (95.6154, ± 21.27150) for group one & group tow respectively. Also, patients had average thickness RNFL (left eye) with mean & standard deviation (1.0930E2, ±23.80177), (98.7500, ± 23.77334) for group one & group tow respectively. Conclusions: This study found CCT effective with dialysis tend to be thin (53 patient,18 patient in group one &35 in group two) and that will be had a threefold higher risk of developing glaucoma when compared with thick average because of the IOP value affected by it. Refractive error effective with dialysis & become was more prominent that can be shown in the group two have (40 patient from 52) while (15 patient from27) in the group one although a lot of them corrected to the BCVA. In conclusion high value of the C/D ratio formed about (45.57%, 53.16%) to the right &left eye respectively this value will be form important sign of risk factor to progressive of glaucomatous need to be alert in the future. Also our research reveals CFT effective undergoing dialysis the thick value was (56 in the right eye, 55 in the left eye) high compared with the thin (9 in the right&9 in the left eye) & normal (14 in the right eye, 15 in the left eye). All the two groups of patients will be effected by the duration of dialysis with a time.

Effects of CeO2 and Sb2O3 on the Nonlinear Photochemical Process in Ultrashort Laser Gaussian-Bessel Beams Irradiated Photo-Thermo-Refractive Glass.

Microfluidic chips and optical elements can be fabricated based on the nonlinear photosensitivity in photo–thermo–refractive (PTR) glass by controlling the growth of nanocrystals in the femtosecond (fs) laser–irradiated region. Here, we focus on CeO2 and Sb2O3 that play important roles in UV irradiation, experimentally investigate the effects of the dopants on the nonlinear photochemical process in PTR glass triggered by fs Gaussian–Bessel beams. The results show that the generation of Ag0 atoms and the Ag nanoparticles can be improved by CeO2 and Sb2O3 co–doping. Besides, each multivalent ion in PTR glass possibly participates in the electron transfer processes and contributes to the generation of Ag0 atoms. Finally, X–ray diffraction analysis reveals the precipitation of NaF nanocrystals with an average size of 10 to 12 nm after laser irradiation and thermal treatment, which is unrelated to the dopants.

Effects of modifier oxides in the nonlinear refractive index of niobium-borotellurite glasses

This work investigates the influence of transition metals oxides (Ta2O5 and ZrO2) on the nonlinear refraction of niobium-borotellurite glasses prepared by melt-quenching technique. The closed-aperture Z-scan technique was used to measure the nonlinear refractive index (n2) spectrum from 470 nm to 800 nm. Also, the BGO (Boling, Glass, and Owyoung) approach was used to model nonlinear spectra, considering the oxygens present in the sample as the major contribution to the nonlinearity. The samples’ molar electronic polarizability was determined to further understanding the effect of the transition metals oxides on the optical properties. Structural analysis was performed by differential scanning calorimetry, Raman and Infrared spectroscopies. The results indicate that although the modifier oxides affect the structural units and glass polarizability, they are not enough to change the behavior of the nonlinear refractive index spectra, being the glass-matrix the main responsible for optical nonlinearity in the system studied here.

30‐2: High Refractive Index Glass Wafers for Augmented Reality: Boundary Conditions for an Excellent Optical Performance

Planar, high refractive glass wafers are the backbone of leading Augmented/Mixed Reality devices. They route the virtual image to the user's eye, while helping to keep the form factor small. While the glass characteristic directly affects fundamental design parameters like Field‐of‐View, the optical system of the wafer with its surfaces and interfaces as a whole determines the image quality. Besides surface quality of the glass itself, the adjacent coatings, such as anti‐reflective coating and polymer coating with a grid structure can significantly contribute to the total optical loss. Here we are reporting on optical losses caused by surface effects and polymer coatings that might lead to disadvantages in key quality parameters, such as contrast, brightness and distortion of the image.

Nonlinear refraction and absorption spectroscopy of tellurite glasses within telecom bands

In this work we determined the nonlinear refractive index (n2) and the two-photon absorption coefficient (β) spectra of seven different tellurite glasses by open-aperture nonlinear ellipse rotation (NER) measurements. In order to demonstrate the potential of these vitreous systems for telecommunication applications, their nonlinear responses were characterized in the range of 1200–1600 nm. Aiming all-optical switching applications, figures-of-merit (FOMs) were calculated, based on n2, α0 and β coefficients. The FOMs results indicate that the investigated tellurite glasses compositions are promising materials for all-optical switching within the telecom wavelength range.

Scanning probe microscopic study of P(VDF-TrFE) based ferroelectric nanocomposites

Ceramic and polymer based nanocomponents combine the properties of their constituents, e.g. flexibility, elasticity, polymer reprocessability, hardness typical of glass, wear resistance and high light refraction index. This helps improving many properties of the materials in comparison with the source components. Since recently researchers have been manifesting interest to the properties of complex composite compounds. This is primarily caused by the unique properties of their structures as compared with conventional materials having homogeneous composition. Secondly, this interest is caused by the fact that these compounds may prove to be much cheaper than homogeneous structures provided the physical properties of the composite in a preset range of parameters (temperature, applied field frequency etc.) are identical to those of the respective homogeneous materials. For example, polyvinyl idenfluoride (PVDF) type ferroelectric polymers and copolymers on its basis have found wide application for functional elements of various electromechanic devices in advanced electronics due to their relatively good piezoelectric and pyroelectric properties. The strong random polarization and the formation of polar non-centrosymmetric crystals provide for the high piezoelectric and pyroelectric activity in these crystals. Scanning probe microscopy has been used for study of ferroelectric nanocomposites having different compositions. The matrix specimen for study of local polarization switching at a nanoscale level was vinyl idenfluoride and trifluoroethylene P(VDF-TrFE) copolymer possessing sufficiently high crystallinity. The composite fillers were barium titanate BaTiO3 and deuterized triglycinsulfate DTGS ferroelectric powders and zirconate-titanate lead barium BPZT ceramic powder. We show these materials to show good promise for use in memory cells.

Co-relation of Myopia with the Use of Smart Phones and Outdoor Activities

Purpose: To determine the frequency of myopia among children and to find out the role of smart phone usage and outdoor activities in myopia development and progression.
 Study Design: Descriptive cross-sectional study.
 Place and Duration of Study: Ophthalmology department DHQ-UTH Gujranwala, from January 2019 to June 2019.
 Methods: After approval from the hospital ethical committee and informed consent from each participant, a descriptive cross-sectional study was carried out with a sample size of 250 patients. Patients of either gender between 4 – 14 years of age using smart phones for ≥ 2 hours daily and found to have refractive error were included in this study. Routine ophthalmic examination was carried out, data was recorded on proforma, and daily usage of smart phones and weekly outdoor activity in hours along with school grade, family history and previous history of using refractive glasses was also determined and documented. Data was analyzed using SPSS v.20
 Results: 250 patients were included in this study, out of which 142 (56.8%) were male and 108 (43.2%) were female. Mean age was 10.1 ± 2.45 years. Mean outdoor activity was 0.95 ± 0.98 hours per week while mean daily smart phone usage was 2.89 ± 0.93 hours. Pearson correlation coefficient for daily smart phone usage and UCVA was +0.297 (0.3) which showed a positive moderate association between two variables while the value obtained for UCVA and weekly outdoor activity was – 0.51 that depicted a negative strong association.
 Conclusions: In conclusion, myopia occurrence is higher among smart phone users showing a moderate positive correlation while outdoor activities reduce myopia prevalence and progression depicting strong negative correlation.
 Key Words: Refractive Errors, Myopia, Visual acuity, Smartphone.