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Tundra lists 25 Refractive Errors clinical trials. Each listing includes eligibility criteria, study locations, and direct links to research sites in the Tundra directory.
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NCT07518316
Factors Influencing Subjective Visual Quality in Human Eyes
To assess subjective visual symptoms using the QoV questionnaire, measure pupil size using the Atongmu Pupillometer, measure wavefront aberrations using the OPD-Scan III Aberrometer, and measure/calculate the effective optical zone using the Pentacam system. The relationships between pupil size, higher-order aberrations (HOAs), effective optical zone after refractive surgery, and subjective visual symptoms will be explored.
Gender: All
Ages: 18 Years - 45 Years
Updated: 2026-04-08
NCT05856786
To Study the Effects of Refractive Surgery on OCT Measurements in the Eye
Corrective eye surgeries, such as Lasik, are widely used to correct focusing problems such as myopia, or nearsightedness. Often these patients develop other conditions like myopic maculopathy or glaucoma which require monitoring with optical coherence tomography (OCT). Since OCT is a light-based test and changes the refractive status of the eye (in the cornea or the lens), it can potentially affect the results of the OCT measurements but has not been sufficiently studied. This pilot study aims at studying the potential change in OCT parameters in the eye after undergoing such surgery.
Gender: All
Ages: 19 Years - Any
Updated: 2026-03-18
1 state
NCT07460557
Morphological Characteristics of the Maxillomandibular Region in a 3D Representation and the Refractive Status of the Eye
The goal of this observational study is to learn more about the relationship between the size and shape of the eye and the shape of the face in healthy young adults. In particular, the study focuses on whether specific eye measurements are linked to certain facial characteristics after growth and development have been completed. The main question it aims to answer is: Does the size and internal structure of the eye relate to the three-dimensional shape of the face in young adults aged 21 to 25, and are these relationships different in people who are nearsighted (myopic), farsighted (hyperopic), or have normal vision (emmetropic)? Refractive errors such as nearsightedness and farsightedness are very common and are largely influenced by the length of the eye (axial length) and other internal eye measurements. During childhood and adolescence, it develops at the same time as the eye socket (orbit) and the bones of the face. However, most previous studies have examined either the eye or the bony orbit separately. Very few have combined detailed eye measurements with modern three-dimensional (3D) facial measurements in the same individuals. This study will include 120 healthy young adults between 21 and 25 years of age, after facial growth is complete. Participants will be divided into three groups based on their refractive status: myopic (nearsighted), emmetropic (normal vision), and hyperopic (farsighted), with similar numbers of men and women in each group. All participants will undergo a standard ophthalmologic examination. This will include measurement of visual acuity, refraction (to determine glasses prescription), and detailed eye biometry using a non-contact optical device (IOLMaster 700). The measurements will include axial length (eye length), corneal curvature, anterior chamber depth, lens thickness, and corneal diameter (white-to-white). These are routine, non-invasive measurements commonly used in clinical eye care. In addition, participants will undergo non-invasive 3D facial imaging. A short video of the face will be recorded while a camera moves around the participant. Using photogrammetry software, this video will be converted into a precise 3D model of the face. From this model, specific facial landmarks will be identified, and distances and proportions of different facial regions (upper, middle, and lower thirds of the face; cheek width; jaw width; chin projection) will be measured. This method does not involve radiation and does not cause discomfort. The researchers will then analyze whether there are statistical relationships between eye measurements and facial dimensions. They will also compare the three refractive groups to determine whether certain facial patterns are more common in myopic, emmetropic, or hyperopic individuals. Participation is voluntary. All participants will sign informed consent before enrollment. The study has been approved by relevant ethics committees and will be conducted according to international ethical standards. All data will be anonymized and stored securely. No additional risks are expected beyond those associated with a routine eye examination. The results of this study may improve understanding of how eye growth and facial development are related. In the long term, this could contribute to better knowledge of the anatomical background of refractive errors and support future interdisciplinary research in ophthalmology, orthodontics, and craniofacial medicine.
Gender: All
Ages: 21 Years - 25 Years
Updated: 2026-03-10
NCT05458323
Cognitive Level Enhancement Through Vision Exams and Refraction
The investigators aim to conduct a mixed-method study in which a randomised controlled trial (RCT) and a descriptive qualitative study will be conducted. The RCT aims to determine whether free near and distance glasses provided to residents in Hyderabad, India, aged ≥ 60 years, with under- or un- corrected refractive error and normal baseline hearing and cognition (HMSE \> 18), can improve quality of life, reduce falls, reduce depression, improve social interaction and physical activity cost-effectively over 36 months. The primary qualitative research aim is to a) contextualize the RCT with information on the milieu and culture in which the trial will be conducted; b) provide data on the lived experiences of older adults with reduced vision in the study area, and c) conduct a process evaluation of the trial. The primary outcome measure is the three-year change in cognition measured by LASI- DAD (Longitudinal Aging Study in India(LASI)- Diagnostic Assessment of Dementia(DAD) global cognitive score. Secondary Outcome Measures: Three year change in Quality of Life score measured by WHO QOL-BREF; Visual functioning from the RASCH-scaled version of INDVFQ(Indian Visual Functioning(INDVFQ);self-reported physical activity score measured using IPAQ questionnaire; PHQ9 score; domain specific cognitive score (orientation, executive function, language/fluency, memory) measured by HMSE; Total cost of care including direct and indirect costs; Quality adjusted life years; Incremental Cost Effectiveness Ratio; Number of falls measured by Quick Screen score over the three years; Social network density at 3 years (SNI 1-3 represents a "limited" social network, 4-5 is a "medium" social network, and SNI ≥6 is a "diverse" social network) measured by the SNI score; An additional secondary outcome will be LASI-DAD global cognitive score analysed by excluding any tests determined pre-hoc to depend on visual acuity.
Gender: All
Ages: 60 Years - Any
Updated: 2026-03-06
1 state
NCT07036835
Clinical Investigation of a Femtosecond Laser for Corneal Flap Creation
The purpose of this study is to see how safe the WaveLight Ultraviolet Femtosecond Laser, Model 1026 (UV fs-Laser), is for creating corneal flaps during laser-assisted in situ keratomileusis (LASIK) surgery. This study will be conducted in Australia.
Gender: All
Ages: 18 Years - Any
Updated: 2026-01-13
1 state
NCT07333248
Strengthening Community- to- Hospital Eye Care Pathways From Boko Eye Care Center in Rural Assam
This operational research project aims to strengthen continuity of eye care delivery between community screening and hospital-based treatment in rural Assam by redesigning referral pathways from the Boko Eye Care Center (ECC) to Sri Sankaradeva Nethralaya (SSDN) base hospital. Despite active outreach in the Boko region from the Boko ECC through conducting regular outreach screenings, less than 30 percent of patients referred to the base hospital actually arrive for evaluation and less than 25 percent of those advised for surgery proceed to treatment. The proposed study addresses these gaps by examining behavioural, structural and logistical barriers to referral completion and surgical uptake, and by implementing a coordinated patient-centered referral and engagement strategy. The proposed intervention comprises of five sequential components: (1) root cause analysis to identify bottlenecks and facilitators in the current referral pathway, (2) community engagement activities to improve awareness and proactive health-seeking behaviour, (3) implementation of an integrated referral and engagement model supported by trained community team and structured referral tracking, (4) strengthening referral completion through patient navigation, scheduled transport and follow-up reminders, and (5) enhancement of surgical acceptance through standardized counseling, affordability support and social reinforcement. The outcomes will be measured prospectively, focusing on increase in hospital footfall from the Boko catchment area, proportion of referred patients who complete hospital visits, and proportion of patients who were advised for surgery and had undergone the procedure. The proposed project aims to achieve a minimum of 70 percent referral completion and 45 percent surgical conversion by the end of the 36-month study period.
Gender: All
Ages: 18 Years - Any
Updated: 2026-01-12
1 state
NCT06996353
Clinical Data Collection of Myopic Patients After PTK-PRK With CZM MEL 90 Excimer Laser
The objective of the clinical investigation presented to is to verify predictions of post-operative PTK-PRK refractive outcome made by the EpiMaster application software by comparing these to post-operative clinical data after routine PTK-PRK treatments.
Gender: All
Updated: 2026-01-09
2 states
NCT07240480
Assessing the Turkish DDIVAT for Visual Acuity Measurement
The goal of this observational methodological study is to validate the Turkish version of the DDIVAT visual acuity measuring device in a Turkish-speaking adult population. The main questions it aims to answer are: Does the Turkish version of the DDIVAT provide reliable and valid visual acuity measurements in Turkish speakers? Are the results of the DDIVAT comparable to those obtained with the standard Snellen chart used in clinical practice? Researchers will compare DDIVAT visual acuity test results with Snellen chart results to see if both methods produce consistent measurements. Participants will: Be adults aged 18 years or older, including both patients and healthy volunteers. Undergo visual acuity testing using the DDIVAT system displayed on a smart TV connected to the university server. Have their visual acuity re-measured using the standard Snellen optotype under the same conditions. No medication or invasive procedure will be used. The study carries no risk to participants.
Gender: All
Ages: 18 Years - Any
Updated: 2025-12-04
NCT07257536
Xinxing Eye Cohort Study
To establish the baseline levels and monitor the progress of two newly introduced global eye health indicators in Xinxing County, including effective refractive error coverage (eREC) and effective cataract surgery coverage (eCSC). And to assess the prevalence and treatment status of common eye disease in Xinxing County.
Gender: All
Ages: 0 Years - 100 Years
Updated: 2025-12-02
NCT07241806
Measurment of Optic Disc Parameters, RNFL Thickness and Ganglion Cell Complex in Myopic, Hypermetropic and Emmetropic Patients Using OCT and Axial Length Measurments
To evaluate the optic disc parameters, thickness of ganglion cell complex (GCC), and thickness of peripapillary retinal nerve fiber layer (RNFL) in myopic and hyperopic and emmetrop patients using optical coherence tomography (OCT), and to correlate these changes with axial length and degree of refractive error.
Gender: All
Ages: 18 Years - Any
Updated: 2025-11-21
NCT03030755
Corneal Elastography and Patient Specific Modeling
The goal of this research is to develop measurement tools and simulation technology for characterizing and predicting individual responses to corneal treatments and for advancing understanding of corneal ectasia risk factors. Patients who either 1) have keratoconus and are being evaluated for corneal crosslinking or 2) have refractive error and are being evaluated for refractive surgery procedures such as LASIK will have their eyes imaged to assess their mechanical properties and will have computational simulations performed to predict the response to treatment. One aim of the study is to test the hypothesis that computational models can predict the cornea's shape changes within clinically acceptable limits of error.
Gender: All
Ages: 16 Years - 80 Years
Updated: 2025-10-22
1 state
NCT04740593
The Effect of Early Glasses on the Development of Amblyopia
In a randomized controlled trial, we will establish whether early glasses for high refractive error at age one reduce the development of amblyopia between age one and four. As a secondary outcome early literacy will be compared in groups with and without glasses.
Gender: All
Ages: 12 Months - 18 Months
Updated: 2025-08-11
NCT07001124
Comparative Efficacy of Duochrome Test Verse +1 Blur Test in Detecting Refracting Error Across Different Ages
The comparative efficacy of the duochrome test versus +1 blur test in detecting refractive errors across different ages remains under-explored in current ophthalmic research. While the duochrome test is widely used to refine prescriptions, its standalone effectiveness compared to +1 blur test based refraction has not been thoroughly investigated.
Gender: All
Ages: 18 Years - 60 Years
Updated: 2025-07-16
1 state
NCT06112431
Eye Health Intervention Study in Upper Manhattan
Individuals living in Upper Manhattan have limited access to eye care, high vision impairment rates, and poor ocular health outcomes. To improve eye care and vision health outcomes, the Eye Health Intervention Study in Upper Manhattan (EYES-UM) will conduct eye health screenings in accessible primary care health centers and senior centers and implement a behavioral intervention to improve adherence for those referred for in-office eye care. The proposed innovative, 2:1 cluster-randomized clinical trial, will recruit adults age 40 and older in Upper Manhattan with known rates of inadequate eye care. A total of 10 settings in Upper Manhattan, comprised of primary care offices, senior centers, and organizations, confirms access to 17,000 individuals living at or below the NYC.gov poverty measure. This study will conduct ocular tests (visual acuity, intraocular pressure, fundus images) during screenings. To ensure that all participants receive the basic level of service, all participants who fail the eye health screening will be seen the same day by a study optometrist and eyeglasses will be provided at no charge. Educational workshops and an Advisory Board will support recruitment. Intervention Arm participants will receive ongoing support with scheduling eye exams and transportation by trained Study Coordinators. All participants will be followed prospectively for 2 years. The study is guided by the Reach, Effectiveness, Adoption, Implementation, and Maintenance (RE-AIM) Framework. Conducting Focus Groups with health policy stakeholders ensures iterative input during the study to bridge and translate EYES-UM findings into a Vision Health Policy Roadmap for scalable implementation of vision care delivery models, focusing on adherence.
Gender: All
Ages: 40 Years - Any
Updated: 2025-05-25
1 state
NCT06913491
Efficacy of PEEK Acuity Versus ETDRS Chart for Assessment of Visual Acuity and Refractive Error
Visual acuity is a key indicator of visual function, often measured using the ETDRS chart, the gold standard in clinical settings. However, the increasing need for accessible and cost-effective screening tools, especially in underserved areas, has led to the development of mobile health applications like the Peek Acuity application.
Gender: All
Ages: 18 Years - Any
Updated: 2025-04-06
1 state
NCT05550740
Repeated Low-Level Red-Light Therapy for Shortening Axial Length
The purpose of this clinical trial is to confirm the incidence and magnitude of axial length shortening after RLRL therapy in Chinese high myopia children and teenagers.
Gender: All
Ages: 6 Years - 16 Years
Updated: 2025-03-30
1 state
NCT05670626
Correlation Between Preoperative Refraction and Anterior Segment Parameters With ICL Vault
This prospective non-comparative interventional study aims to analyse the pre-operative factors affecting the range of optimal ICL vaulting. the main question is what is the correlation between age, gender, spherical equivalent, white to white, anterior chamber volume and depth and postoperative vault? participants will do preoperative investigations ( specular microscopy, pentacam and biometry ) then refractive surgery (ICL implantation) followed by follow-up visits to assess the post-operative ICL vault and visual outcome.
Gender: All
Ages: 21 Years - 45 Years
Updated: 2025-03-13
1 state
NCT06849895
Real-World Study of Myopia Prevention and Control in Children
This prospective, school-based cohort study aims to enroll approximately 15,000 primary school students from multiple districts in Shanghai, China and to observe the outcomes on myopia prevention and control in children with varying refractive status (including sufficient hyperopia reserve, relative insufficiency in hyperopia reserve, pre-myopia and myopia) who are exposed to a school-based categorized and integrated interventions strategy in real-world settings. The primary objective of this study is to observe the change in the incidence and prevalence of myopia as well as the the progression of myopia among primary school students population under a school-based interventions, including increasing outdoor activities and wearing special designed optical lenses. The second objective is to identify factors influencing the outcomes and assess the compliance of different intervention methods. Additionally, a cost-effectiveness analysis will be conducted to assess the implementation process, providing technical solutions and operational models for wider application.
Gender: All
Ages: 6 Years - 12 Years
Updated: 2025-02-27
1 state
NCT04632784
Clinical Trial With Artiflex Presbyopic (Artiplus)
The purpose of this clinical trial is to evaluate the effectiveness and safety of the multifocal Artiflex Presbyopic (Artiplus) intraocular lens.
Gender: All
Ages: 18 Years - Any
Updated: 2025-02-20
2 states
NCT04077086
Correcting Myopia Among Secondary School Children to Increase Academic High School Attendance Rates in Rural Communities
Chinese children are some of the most short-sighted in the world, but only one in five children in poor areas who needs glasses has them. Our team has already shown in other trials that giving children free glasses leads to better grades and that free glasses have a bigger impact on grades than factors like parents' education level and the amount of money a family has. The effect on grades from glasses is greater than from other health services in school, like giving vitamins. Only about one in three children in rural China goes on to a regular, non-vocational high school. The investigators would like to show the Chinese government strong evidence of what glasses can do to help children continue their education, in order to help convince the government to carry out national programs to provide free glasses for children who need them. Study Plan: The investigators will choose 111 middle schools at random in Liaoning, northern China, and all children in Year 1 at each school will go at random into one of two groups: either a group getting free glasses, with support from teachers to push them to wear the glasses ("Intervention") or a group getting just glasses prescriptions ("Control.") The main study outcome will be the proportion of children going on to academic (as opposed to vocational) high school, and the study is powered to detect a 10% difference in this figure between groups.The study will also assess whether children wear their glasses at school and how often they use blackboards (which disadvantage short-sighted children) vs textbooks to learn from. These other outcomes will help us to better understand the causal pathway between vision and high school attendance. We will also study the total cost of providing glasses and the teacher support to wear them per additional student attending academic high school, as well as student mental health outcomes. We will also collect data on the progression of nearsightedness. The hypothesis of this study is that providing glasses will increase academic high school attendance.
Gender: All
Ages: Any - 18 Years
Updated: 2024-12-27
3 states
NCT06668246
Performance of Refractometers With Self-adjusting Lenses Compared to Cycloplegia in Children (REFRALENS)
This study aimed to compare refractive measurements using Vision-S™ 700, an immersive and compact phoropter with a tunable-focus lens, and Vision-R™ 800, a phoropter with a tunable-focus lens without immersion, with cycloplegic refraction serving as the gold-standard. This a retrospective study aimed to enroll 41 children, aged 6 to 16 years, who underwent refractive assessments with Vision-S™ 700, Vision-R™ 800, and cycloplegic refraction. The primary objective involves a comparison of the spherical equivalent between both devices and compared to cycloplegic refraction. Secondary outcomes include the analysis of astigmatism components (J0° and J45°) and subgroup analyses in myopic and hyperopic children.
Gender: All
Ages: 6 Years - 16 Years
Updated: 2024-11-01
NCT06565091
Clinical Investigation for a Multifunction Ophthalmic Measurement Device
The purpose of this clinical investigation is to evaluate the clinical utility of a multifunctional measuring device for Ophtalmology. The results of this clinical investigation will be used to refine and validate the device design. 378 participants total will be included in the trial, each having only one visit at the investigation center.
Gender: All
Ages: 4 Years - Any
Updated: 2024-08-21
NCT06379477
Correction of Refractive Error Surprises After Cataract Surgery in Adults
A refractive surprise can be defined as the failure to achieve the intended postoperative refractive target or the presentation of unexpected and, unwanted post-operative refractive error. It can cause anisometropia or dominance switch and is a source of patient dissatisfaction due to unmet expectations.The best way to manage refractive surprise is to prevent it. The 2017 NICE guidelines on the management of cataracts provide advice on prevention of refractive surprise through accurate biometry, A-constant optimisation, intraocular lens (IOL) formula selection and avoiding wrong lens implant errors.Benchmark standards for NHS cataract surgery dictate that 85% of eyes should be within 1 dioptre (D) and 55% within 0.5D of target spherical equivalent refraction following surgery.
Gender: All
Ages: 55 Years - 75 Years
Updated: 2024-04-23
NCT05715424
Community Intervention and Demonstration Area Construction
The objective of this intervention study was to understand the visual health status of nearly one million children and adolescents in ten provinces in China, and then to conduct intervention and evaluate the effect of intervention measures with the development of myopia as the outcome indicator. The study will be conducted in the form of a stepped intervention and will answer the following questions. Current China children and adolescent's vision health, including the different degrees of myopia prevalence, and farsightedness reserve status. To evaluate the implementation and effect of eight appropriate technologies and six interventions developed in this study, to reduce the incidence of myopia among children and adolescents in China, to achieve the purpose of nationwide application. In the early stage of this study, a baseline survey will be conducted on participants. In the middle stage, participants will be required to adjust the seat height regularly and increase the time for outdoor activities, etc. In the later stage, intervention measures will be evaluated based on the overall research situation to consider national promotion.
Gender: All
Updated: 2024-04-09
1 state