Wear Glasses Research Articles

Measurement and analysis of the geometric characteristics of microholes and tool wear for varying tool-workpiece gaps in electrochemical discharge drilling

In the last decade, the Electrochemical Discharge Drilling (ECDD) has emerged as an alternative to conventional laser ablation to create blind and through-holes in non-conductive materials such as fused silica, quartz, and glass workpiece. The initial tool electrode and workpiece (T-W) gap play a vital role in microhole formation and tool wear. Therefore, an experimental investigation into the effect of the initial T-W gap with different machining time and electrolyte concentrations on the blind microhole formation in the glass and tool wear in the velocity-feed ECDD is reported. The microholes having superior surface quality and lower overcut were fabricated with KOH electrolyte and lower concentration. A novel numerical model based on inverse heat flux reduction for varying initial T-W gaps was studied for the first time. The obtained experimental results were compared to the numerical results predicted with the finite element based numerical simulations. The opening size of the microholes increased up to a critical T-W gap and then decreased with a further increase in the gap. The critical gap is found to be 20 µm and 10 µm for NaOH and KOH electrolyte, respectively. The depth of the microholes was the maximum at a zero-gap condition; however, the tool wear was severe. The highest average depth of 175 µm was obtained at 30 wt% NaOH for the machining time of 60 s. Tool wear tends to be decreasing with increasing the T-W gap. The least average tool wear of 9 µm was observed for 20 wt% KOH electrolyte for machining time of 60 s. The experimental results indicated that the conventionally used gravity-feed mechanism is not suitable from the tool wear point-of-view, and a particular initial T-W gap should be maintained during the ECDD process. The T-W gap between 10 and 30 µm for the NaOH electrolyte and 5–20 µm for the KOH electrolyte is recommended.

Synergy between surface mechanochemistry and subsurface dissolution on wear of soda lime silica glass in basic solution

AbstractThe polishing of oxide glass in aqueous solution is sensitive to not only the mechanical conditions applied by abrasives but also the chemistry of solution. This study elucidates the synergistic interactions of mechanical and chemical effects—especially, the synergetic effects of surface mechanochemical wear and subsurface dissolution are studied by measuring the material removal rate of soda lime silica (SLS) glass upon rubbing with a Pyrex glass ball in noncorrosive (neutral pH) in corrosive solutions (pH 10 and 13 NaOH) as a function of sliding speed. Based on the synergetic model of surface wear and subsurface dissolution, it is found that the mechanochemical surface reaction dominates the wear behavior of SLS glass in neutral and pH 10 solution conditions; the wear of SLS glass in pH 10 is enhanced, compared to the neutral pH case, due to the presence of OH‐ ions at the sliding interface. In the case of pH 13, the dissolution of the densified subsurface region, which is formed due to interfacial friction during the surface wear, becomes significant, further enhancing the material removal yield. The finding provides an insight for designing an efficient polishing process in manufacturing of oxide glass materials with a good surface finish.

Wear Behavior of the Human Enamel Antagonist to Different Glazed Zirconia.

In this study, the wear behavior of glazed zirconia was investigated to the antagonist with human enamel after simulated mastication. Twenty Y-TZP specimens were divided into 4 groups: untreated zirconia (Z), glazed zirconia with IPS e.max Ceram (GZE), glazed zirconia with VITA AKZENT® Plus (GZV), and glazed zirconia with glass (GZG). Glazing glass was mainly composed of SiO₂, B₂O₃, Al₂O₃, Na₂O and K₂O (nearly 91 wt%). The surface roughness of the specimens was evaluated using roughness profiler. The maxillary premolar teeth were selected as the antagonist. The wear of human enamel against human enamel was used as a control. Five-disc specimens per group were subjected to chewing stimulation CS-4 (SD Mechatronic GmbH, Germany) for 240,000 cycles against human enamel. The wear loss of antagonistic teeth was calculated using a three-dimensional profiling system and the volume loss of the tooth was scanned using a 3D scanner. 3D data obtained before and after testing were overlapped using 3D software (Dentacian Software, EZplant, Korea). The wear loss of glazed zirconia GZE, GZV and GZG groups showed significantly lower than that of human enamel. Whereas, the zirconia (Z) group exhibits significantly lower volume loss than glazed zirconia and enamel. These results show that the wear of the glazing glass is comparable to other commercial glazing materials. Glazing materials are both more susceptible to wear the antagonist relative to zirconia.

Tribological and thermogravimetric analysis of pineapple fibre reinforced epoxy composite

Natural fibre composites are preferred for various static and dynamic applications owing to its biodegradable capacity and strength. Pineapple fibres obtained by the retting process from pineapple leaf were successfully reinforced with epoxy resin with different fibre volume percentage. The wear rate and the thermogravimetric analysis of the polymer composite were studied. It was discovered that 30% reinforcement of pineapple fibre resulted in better wear and higher glass transition temperature due to the optimal fibre volume fraction and enough wetting of the resin on the fibre.

Eye pupil localization algorithm using convolutional neural networks

Eye pupil localization is one of the indispensable technologies in various computer vision applications such as virtual reality and augmented reality. In general, the algorithm consists of finding the approximate eye region and finding the pupil position by extracting the semantic feature from each eye region. However, the performance of the eye pupil location is affected not only by illumination and image resolution but also by glasses wear. Therefore, this paper proposes an eye pupil localization algorithm which is robust against the above disturbance conditions and provides high accuracy. First, a face is detected from an input image and it is determined whether to wear glasses using the detected face. If glasses are present, the glasses are removed to find the correct eye region. Then, facial landmarks are extracted, and eye regions are detected based on facial landmarks. Next, the pupil region is segmented using fully convolutional networks. Finally, the position of the segmented pupil is calculated. Experimental results show that the proposed algorithm outperforms the state-of-the-art algorithms for public databases such as BioID and GI4E by up to 3.44% 0.5%, respectively.

Effects of nanoscale chemical heterogeneity on the wear, corrosion, and tribocorrosion resistance of Zr-based thin film metallic glasses

The effects of nanoscale chemical heterogeneity on the wear, corrosion, and tribocorrosion resistance of ZrCuNiAl thin film metallic glasses were investigated by examining samples of similar global composition but with either homogenous or heterogeneous local composition. Unlike the homogenous sample, the heterogeneous sample exhibited local compositional fluctuations of Zr-rich (~52.8 at.%) and Zr-lean (~51.7 at.%) regions separated by ~413.0 ± 64.7 nm. Dry scratch wear study showed that the homogenous samples exhibited lower wear rates and friction coefficients than their heterogenous counterparts due to their higher hardness and lower stiffness, as measured from nanoindentation tests. Corrosion resistance of both samples was studied through potentiodynamic polarization and Mott-Schottky analysis in 0.6 M NaCl aqueous solution under room temperature. It was found that the heterogeneous samples exhibited higher pitting resistance than their homogenous counterparts by forming a protective passive layer with lower defect density. Finally, the effects of chemical heterogeneity on the tribocorrosion rate and repassivation kinetics of both samples were discussed based on their differences in mechanical and electrochemical properties measured.

Simple solutions for the fogging of spectacles when wearing surgical masks

During day-to-day wearing of surgical masks, especially in the time of the COVID-19 pandemic, vision is hampered for health care workers who wear glasses due to fogging (Fig 1, A). Although there are various measures, such as hydrogel patches, that can be used to prevent fogging,1 they may not be available or affordable in resource-poor settings.

One-Part Alkali-Activated Pastes and Mortars Prepared with Metakaolin and Biomass Ash

Common alkali-activated materials (AAMs) are usually manufactured with highly alkaline solutions. However, alkaline solutions are dangerous for workers who must wear gloves, masks, and glasses when handling them. This issue makes common (or two-part) AAMs not user-friendly and problematic for bulk production if no safety procedures are followed. In this paper, the possibility of manufacturing alkali-activated pastes and mortars without alkaline solution is investigated. These innovative one-part AAMs have been prepared with metakaolin as the aluminosilicate precursor, potassium-rich biomass ash as the alkaline activator, and water. AAMs have been prepared by varying the K/Al molar ratio: pastes have been studied in terms of reaction kinetics, through isothermal calorimetry, and mortars have been tested in terms of mechanical compressive strength. Results show that the K/Al molar ratio governs both the reaction kinetics and the mechanical strength of these innovative materials. The highest compressive strength is obtained when the K/Al ratio is equal to 2.5 and the water/solid ratio is equal to 0.49. If biomass ash is heated at 700 °C to decompose the calcium carbonate, its reactivity and the final compressive strength increase.

Implantable collamer lens for the correction of post-keratoplasty myopia and astigmatism

AIM: To evaluate the safety, refractive outcomes and vision after phakic posterior chamber implantable collamer lens (ICL) after keratoplasty (KP). METHODS: This retrospective single center study evaluated 32 (35 eyes) patients who received an ICL for myopia and/or astigmatism after keratoplasty. Patients underwent ICL surgery if they were unable to wear glasses or contact lenses and excimer laser surgery was contraindicated. Data were collected on uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refraction and complications. Data were analyzed for the preoperative and last postoperative visits (16.7±13mo) (P<0.05). RESULTS: Preoperatively, spherical equivalent (SE) ranged from -4.00 to -20.00 D and cylinder from -2.00 to -9.00 D. The mean SE decreased statistically significantly from -11.41±3.62 D preoperatively to -1.95±1.78 D postoperatively (P<0.0001). Mean UDVA increased statistically significantly from 20/400 preoperatively to 20/25 postoperatively (P<0.0001). There was a mean improvement in postoperative CDVA of 1.5 lines compared to preoperatively, 37% of eyes had an increase of 2 or more lines. One eye (2.8%) lost ≥1 line of CDVA. There were no intraoperative or postoperative complications. CONCLUSION: Posterior chamber phakic intraocular lens implantation is a safe and effective treatment for post-keratoplasty myopia and astigmatism in patients unable to wear spectacles or contact lenses and where corneal refractive surgery is contraindicated.

Presbyopia Treatment With Eye Drops: An Eight Year Retrospective Study.

PurposeThe purpose of this study was to evaluate the safety and efficacy across time, of patients topically treated with Benozzi's method for presbyopia.MethodsA nonrandomized case series retrospective study was developed, including patients with emmetropia with binocular uncorrected distance visual acuity (UDVA) of 25/20 or better, and with uncorrected near visual acuity (UNVA) at least Jaeger 2 or worse. The study was set in Buenos Aires, Argentina, from January 2011 to June 2018, with at least 1-year follow-up. Patients were treated with pilocarpine and diclofenac preservative-free eye drops (Benozzi Method; US 8.524.758 B2, EP1.938.839 B1), and the main outcome measured was binocular UNVA at different follow-up times. Other parameters, as the UDVA and presence of side effects, were evaluated.ResultsA total of 910 patients were included with a mean age at baseline of 48.67 ± 3.72 years old (range, 40–59 years). The baseline UNVA was 4.74 ± 1.53 and at 8 years of follow-up was decreased to 1.36 ± 0.48 (Jaeger scale). The mean binocular UDVA at baseline was 0.00 ± 0.01 logarithm of the minimum angle of resolution (logMAR) and after 8 years of follow-up was 0.03 ± 0.04 logMAR. All side effects reported (decrease of light perception, headaches, symptoms of ocular surface dryness, and dizziness) were spontaneously resolved in patients who continued with the treatment.ConclusionsThe efficacy of the pharmacological treatment of presbyopia to improve the UNVA without affecting the UDVA is shown. Side effects were well tolerated and resolved before 1 year of treatment.Translational RelevanceThis is a nonsurgical option for patients with emmetropic presbyopia who do not wish to wear glasses, which is a pharmacological treatment with eye drops.

Knowledge and Preference for Refractive Surgery and Preferred Methods of Refractive Correction among Patients with Significant Refractive Errors Attending Bharatpur Eye Hospital, Nepal

Background: Refractive errors are a major cause of defective vision in all age groups. Although contact lens and refractive surgery are popular, still spectacles are the traditional and most widely used method of optical correction. The main objective of the study was to determine the knowledge and preference for refractive surgery and preference for refractive correction.
 Materials and Methods: Questionnaire based study was conducted among 252 participants aged between 22-40 years with significant refractive errors (>±1.00D) for a period of three months between June to August 2017. Participants who had prior refractive surgery and not willing to participate were excluded from the study.
 Results: One hundred and forty (55.6%) were males and majority (76.6%) of the participants were in the age range 22-30 years. Myopia (60%) was more prevalent followed by astigmatism (38%) and hypermetropia (2%) with refractive power between 1-3 D in 72.5% of participants. Only 61(24%) of the participants had knowledge about refractive surgery. Forty three percentages of them knew from their friends, internet was source of information for 36% and only 19% of them knew from eye care professionals. Majority (87.3%) preferred spectacles 4.8% preferred contact lens and only 8% preferred refractive surgery as methods of refractive correction. Only 44% showed willingness for refractive surgery when available at Bharatpur Eye Hospital. Participants with prior knowledge (p=0.002), higher refractive error and longer duration of glass wear (P=0.005) had more preference for refractive surgery.
 Conclusion: The knowledge, preference and willingness for refractive surgery were less with spectacle being the most preferred methods of refractive correction.

A biocompatible Pd-based BMG with excellent corrosive-wear resistance for implant applications

The mechanical properties, electrochemical behavior, wear and corrosive-wear performance of a Pd40Cu30Ni10P20 bulk metallic glass (BMG) were studied. It is found that the Pd-based BMG shows high hardness of over 500 HV, which is superior to that of conventional biomedical alloys, like the CoCrMo alloy, 316 L stainless steel (SS), and Ti6Al4V alloy. The Pd-based BMG possesses a great corrosion resistance in the phosphate buffer saline (PBS) solution, which is ascribed to the formation of a highly-protective Pd-enriched sub-surface structure. The Pd-based BMG exhibits the greater dry- and corrosive-wear resistance than that of traditional crystalline biomedical alloys studied in this work. This trend can effectively ensure the working longevity of the Pd-based BMG as orthopedic implant. The triobocorrosion experiment results illustrate that the extremely high corrosive-wear resistance of the Pd-based BMG can be attributed to the high passivation capacity during wet sliding. The possible mechanism of the corrosion-accelerating wear deterioration is discussed, which provides the guidance for the improvement in the corrosive-wear resistance of Pd-based BMGs for their potential biomedical applications.

Plastic Surgeons in Action against Coronavirus Disease 2019 at the First Coronavirus-specialty Hospital in Europe.

Plastic Surgeons in Action against Coronavirus Disease 2019 at the First Coronavirus-specialty Hospital in Europe.

Joint Attention in a Laparoscopic Simulation-Based Training: A Pilot Study on Camera Work, Gaze Behavior, and Surgical Performance in Laparoscopic Surgery.

Introduction: Training in laparoscopic surgery seems to be an important aspect in gaining and maintaining professional competency. In experimental settings, camera navigation skills improved after simulation-based training, but the effect of camera work on the surgeon's performance is not well studied. The aim of this study was to investigate whether a fixed camera or an operated camera, as well as the experience of the camera operator has an effect on the performance of the surgeon. Materials and Methods: The study was performed on the LapSim laparoscopic training system. The task was to tie an intracorporal knot in a static surgical environment with three different camera conditions: fixed camera, camera operated by an inexperienced person (inexpert camera), and camera operated by an experienced surgeon (expert camera). The camera conditions were counterbalanced across trials. Performance variables were completion time in seconds and the extend of movements in path length and angular pathway. Gaze behavior was measured with eye-tracking glasses worn by the surgeon as well as the camera operator and was evaluated for performance-harming effects. Results: Completion time varied across conditions, with participants performing significantly longer in the fixed camera condition than in the expert or the inexpert condition. The expert and inexpert conditions did not differ. The performance-harming effect of non-focusing on the tissue was especially visible in the fixed camera condition but disappeared in the expert camera condition. Neither the camera operators' gaze behavior nor the surgeon-camera operator fixation agreement predicted task performance. Discussion: A camera operator can potentially eliminate performance-harming effects of maladaptive gaze behavior and promote optimal visual behavior of a surgeon. In our experimental task, there was no significant difference in whether the camera operator had previous training in laparoscopic surgery or not.

Eye diseases in travelers.

Travelling has been growing in popularity over the last several decades. Eye diseases, e.g. decreased visual acuity, inflammatory or degenerative lesions, chronic diseases or eye trauma, affect all groups of travelers. The main risk factors contributing to the manifestation or exacerbation of common ocular diseases include exposure to dry air (inside the airplane cabin or in air-conditioned hotel rooms), exposure to chlorinated or salty water (swimming/bathing in swimming pools or in the sea), and sudden changes in the weather conditions. In addition, travelers to tropical destinations are at risk of ocular diseases which are rarely seen in temperate climate, e.g. onchocerciasis, loiasis, gnatostomosis, African trypanosomosis, or trachoma. The most common condition of the eye seen in travelers is conjunctivitis; it may be either of cosmopolitan (bacterial or viral infections, allergic inflammation) or tropical etiology, e.g. arboviral infections (zika, chikungunya). Given the fact that a large proportion of the general population have decreased visual acuity and many of them wear contact lenses rather than glasses, keratitis has become a common health problem among travelers as well; the major risk factors in such cases include sleeping in contact lenses, prolonged exposure to air-conditioning, working with a computer or swimming/bathing in microbiologically contaminated water (e.g. Acanthoamoeba protozoa). Conditions affecting the cornea, conjunctiva or lens may also occur due to excessive exposure to solar radiation, especially if travelers wear glasses without a UV protection.

Esotropia Outcomes and the Influence of Delay to Wearing Full Hypermetropic Correction

To assess whether delay to full hypermetropic correction wear in children might influence the outcome of a diagnosis of full versus partially accommodative esotropia. All children younger than 7 years who were referred with possible strabismus over a 1-year period were assessed. A standard set of details were documented: age at which esotropia was first noticed, age at which esotropia was confirmed by an orthoptist, age at which glasses were prescribed, and age at which full refractive error was constantly worn. When full-time hypermetropic correction was worn, the type of esotropia was determined. There were 430 children referred. Of these, 117 had a concomitant esotropia (62 males and 55 females). Esotropia was confirmed at 35.47 ± 16.67 months of age (range: 4 to 78 months). There were 51 children (43.6%) with full accommodative esotropia, 57 (48.7%) with partially accommodative esotropia, and 9 (7.7%) with nonaccommodative esotropia. Longer delays between the time at which esotropia was identified and the time at which glasses were prescribed were associated with a reduced likelihood of an outcome of full versus partially accommodative esotropia (odds ratio [OR] = 0.73, 95% confidence interval [CI] = 0.58 to 0.93). Delay to glasses wear for full and partially accommodative esotropia was 1.94 ± 6.4 and 6.24 ± 8.36 months, respectively. Higher average spherical correction scores were associated with a higher likelihood of being in the full accommodative esotropia group (OR = 1.35, 95% CI = 1.07 to 1.69). A child with recent onset concomitant esotropia is more likely to achieve full versus partially accommodative esotropia if the delay to full hypermetropic corrective glasses wear is minimized. [J Pediatr Ophthalmol Strabismus. 2020;57(2):85-89.].

Eye-related quality of life and functional vision in children wearing glasses

To evaluate eye-related quality of life (ER-QOL) and functional vision in children wearing glasses using the Pediatric Eye Questionnaire (PedEyeQ). Children 5-17years of age with normal visual acuity who wore glasses for correction of refractive error and with no other eye condition or treatment and control subjects who did not wear glasses, along with 1 parent for each child, were prospectively enrolled. Children completed the Child 5-11 or 12-17 PedEyeQ (four domains); parents completed the Proxy 5-11 or 12-17 questionnaires (perceived effect on child; five domains) and also the Parent questionnaire (effect on parent themselves; four domains). Each domain was Rasch-scored (converted to 0-100), and scores between groups were compared. A total of 40 subjects and 99 non-glasses-wearing controls, along with 1 parent for each child, were included. Children 5-11 and 12-17years of age who wore glasses had lower PedEyeQ scores across all domains compared with controls (mean differences, -6 to -15; P≤0.04 for each domain). Proxy scores were also lower for glasses wearers across age groups and domains (mean differences, -4 to -18; P≤0.02), and Parent scores were lower for parents of children wearing glasses (mean differences, -6 to -18; P<0.001 for each domain). In this study, glasses wearers had reduced ER-QOL and functional vision compared with control subjects. Parents of children wearing glasses also experience reduced quality of life.

Occupational radiation dose to the eye lens of physicians from departments of interventional radiology

Physicians tend to receive extended radiation exposure given the complexity and machine settings of procedures in interventional radiology departments, which involve neurovascular interventional radiology (neuro-IR) and interventional radiology of body regions (general-IR). The eye lens dose was evaluated with direct measurements from the EYE-D™, Hp(3), and indirect estimation from doses measured with over-apron collar dosimeters, Hp(0.07) and Hp(10). The median value of Hp(3) for general-IR procedures was approximately 3.6 times larger than that for neuro-IR procedures. The median value of Hp(3)/kerma-area product (KAP) for physicians who did not wear lead glasses was 1.4 and 2.9 times higher than that for those who wore glasses in neuro-IR and general-IR procedures, respectively. The median value of Hp(3)/KAP for type B glasses (no lateral shielding) wearers was 6.6 and 1.5 times higher than that for type A glasses wearers for neuro-IR and general-IR procedures, respectively. Radiation protective lead glasses can reduce lens dose by 28% and 65% in neuro-IR and general-IR procedures, respectively. Proper lateral shielding is more necessary for radiation protection to the eye lens in clinical situations than is the thickness of the lead equivalent in front of the glasses. Indirect measurements from over-apron collar dosimeters could be a preliminary option for eye lens dose monitoring. However, the underestimation would be 33% of the maximum, which should be specially noted. Dedicated eye lens dosimeters are essential for accurate radiation dose monitoring in neuro-IR and general-IR procedures.

Computer Vision Syndrome Among Health Sciences Students in Saudi Arabia: Prevalence and Risk Factors.

IntroductionComputer vision syndrome (CVS) is defined as a group of vision-related symptoms that result from the continuous use of devices with digital displays, such as computers, tablets, and smartphones. Students nowadays can find resources and books online on their smartphones easily, hence, reducing the use of paper-based reading materials. This might lead to a number of ocular symptoms. In this study, we aim to assess the prevalence and determine the risk factors of CVS among students at King Saud Bin Abdulaziz University for Health Sciences (KSAUHS) in Jeddah.Materials and methodsThis is an observational descriptive cross-sectional study design. Students of Colleges of Medicine, Applied Medical Sciences, and Science and Health Professions at KSAUHS were asked to fill an electronic self-administered survey. The survey instrument included questions on demographic information, digital devices using habits, frequency of eye symptoms, and ergonomic practices. ResultsThe sample size was 334 students, 55% of whom were males. The most used device was the mobile phone (78%), and the most common reason for using an electronic device was for entertainment (80%). The frequency of reported eye symptoms was as follows: headache (68%), feeling of an affected eyesight (short- or long-sightedness (65%)), eye itchiness (63%), burning sensation (62%), excessive tearing (58%), unclear vision (52%), redness (51%), dryness (48.3%), photophobia (47%), painful eye (44%), foreign body sensation (40%), excessive blinking (40%), difficulty in focusing on near objects (31%), halos around objects (28%), double vision (21%), and difficulty moving eyelids (9%). The most commonly applied ergonomic practice was adjusting display brightness based on the surrounding light brightness (82%). The rest of the ergonomic practices were less applied as follows: taking breaks while using the device (66%), sitting with the screen on face level (59%), sitting while the top of the screen on eye level (43%), sitting with the screen more than 50 cm away (32%), using antiglare filter (16%). The number of eye symptoms reported was significantly greater in female students (using Mann-Whitney U test) (U= 11056.500, p= 0.002), students who wear glasses (U= 11026, 0.002), and students who observe glare on their screens (U= 8363, p= 0.043).ConclusionCVS symptoms are commonly reported among health sciences students who use different electronic devices. The occurrence of CVS symptoms was significantly higher among female students, those who observe glare on screens, and those who wear eyeglasses. However, long duration of device use was not significantly associated with increased CVS symptoms. Ergonomic practices are not usually applied by most of the students, which necessitates more efforts to increase their awareness of the correct way of using devices.

Effect of a complex intervention to improve post-vision screening referral compliance among pre-school children in China: A cluster randomized clinical trial

BackgroundWe investigated whether specific appointments for quality-assured care could increase referral uptake, often low in China, in children's vision screening. MethodsWe randomized children aged 4–7 years in Yudu, Jiangxi, China, by school to Control (free school-based eye screening, parents of children failing screening recommended for further examination [usual practice]) or Intervention (identical examinations, with parents additionally provided with specific appointments for further examinations by quality-assured doctors at a designated local hospital). Both groups could select any hospital for referral exams, which were not free. Six months after screening, parents were interviewed on referral compliance at any hospital (primary outcome) and potential determinants. This trial is registered at the ClinicalTrials.gov, number NCT 03251456. FindingsAmong 9936 children at 63 schools randomized to Intervention (32 schools, 5053 [50·9%] children) or Control (31 schools, 4883 [49·1%] children), 1114 children (11·2%) failed screening. Among 513 referred Intervention children (46·1%, 32 schools, mean age 5·36 years, 53·0% boys) and 601 referred Control children (53·9%, 31 schools, mean age 5·30 years, 57·7% boys), 104 (20·3%) and 135 (22·5%) were lost to follow-up respectively. Under Intention to Treat analysis, assuming children lost to follow-up were non-compliant, Intervention children had significantly higher compliance than Controls (308/513 = 60·0% vs. 225/601 = 37·4%, P < 0·001). In regression models, Intervention group membership (Relative risk [RR] 1·53, 95% confidence interval, 1·36–1·72), travel time to hospital (RR: 0·97, 0·95–0·999), baseline glasses wear (RR: 1·37, 1·17–1·60), strabismus (RR: 1·17, 1·01–1·36) and worse uncorrected vision (RR: 1·41, 1·03–1·92) were associated with compliance. InterpretationProviding specific appointments for quality-assured eye care improved referral compliance in this setting.