Myopia, or nearsightedness, is increasing rapidly worldwide, especially in children and young adults. This study will test two advanced treatments for slowing myopia progression with one control group: special lenslet spectacles (Stellest with HALT technology) and violet excitation filter glasses (wavelength 420 nm) and Single vision lenses for controls. The study will enroll 90 participants aged 8 to 20 years from schools and universities in Faisalabad, Pakistan. Participants will be randomly assigned to one of three groups: lenslet spectacles, violet filter glasses, or single vision lenses (control group). Visual acuity, contrast sensitivity, Spherical Equivalent and axial length will be measured at the start and again after 3, 6, and 9 months and one follow up after cessation of treatment. The study aims to determine whether these advanced technologies can effectively slow myopia progression compared to standard glasses, providing head-to-head evidence on emerging and established optical interventions for myopia control.
This is a randomized controlled trial (RCT) with three parallel groups. The study will be conducted at schools and the Universities in Faisalabad, Pakistan. The total study duration is almost one year (July 2025 to May 2026), with each participant undergoing atleast 3 months of active treatment with 3 follow up analysis. The sample size is 30 participants per group (total N=90), after drop of patients, calculated using G\*Power (repeated measures ANOVA, 3 groups × 4 time points, medium effect size f=0.25, α=0.05, power=0.8). Simple random sampling will be used, with participants allocated to groups using an online research randomizer. Inclusion criteria: axial myopia (high, moderate, or severe), age 8-20 years, both genders, willingness to wear glasses. Exclusion criteria: other ametropia, contact lens users, prior myopia treatment, ocular or systemic disease, ocular surgery, non-cooperative patients. Lenslet group: Essilor Stellest spectacles with HALT (Highly Aspheric Lenslet Target) technology, 1.6mm thickness, refractive index 1.56, UV 400nm protection, antireflective coating; worn all waking hours. Violet filter group: CR-39 glasses with 420nm violet excitation filter; worn 3 hours daily (11 AM to 2 PM) to align with circadian rhythm. Control group: single vision lenses (SVS index 1.56). Primary outcome measures: change in axial length (measured by A-SCAN biometer) and change in cycloplegic refraction. Secondary outcome measures: visual acuity (LogMAR chart), contrast sensitivity (Vistech chart). Follow-up assessments at 3, 6, and 9 months. Statistical analysis: repeated measures ANOVA using SPSS version 26 to compare within-group and between-group changes.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
90
The lenslet spectacles are specially designed spectacle lenses featuring HALT (Highly Aspheric Lenslet Target) technology manufactured by Essilor International (Serial Number: 72426930). The lens design includes a clear distance zone in the center with peripheral areas providing single vision correction. Technical specifications: 5H green covering, multi-dimensional pattern, 1.6mm thickness, refractive index 1.56, UV 400nm protection, antireflective coating. Participants are instructed to wear the spectacles throughout all waking hours. Each participant receives a new pair at baseline. No adjustments are made during the 12-month treatment period unless vision changes require prescription update.
The violet excitation filter glasses are prescription glasses incorporating a violet light filter with wavelength 420 nm (range 360-420 nm). Material: CR-39. Filter intensity: 700 nm. Wavelength verified using spectrophotometer (standard error ±0.1 to 1 nm). Participants are instructed to wear the glasses for 3 hours daily, specifically from 11 AM to 2 PM, to optimize impact on circadian rhythm while avoiding disruption of sleep patterns. Each participant receives a new pair at baseline. The filter is integrated into the prescription lenses.
Standard single vision spectacle lenses (SVS index 1.56) with no myopia control features. These are conventional prescription glasses that correct refractive error but do not incorporate lenslet technology or violet filtering. Participants are instructed to wear the glasses throughout all waking hours. Each participant receives a new pair at baseline.
The University of Faisalabad
Faisalābad, Punjab Province, Pakistan
Change in Axial Length
Axial length (mm) measured using A-SCAN biometer (Scanmate 677AB model). Measurement is taken from the corneal apex to the retinal pigment epithelium. Three measurements are taken for each eye, and the average is recorded.
Time frame: Baseline, Month 3, Month 6, Month 9
Change in Cycloplegic Refraction
Cycloplegic refraction (diopters) measured using retinoscope (Welch Allyn) after administration of cycloplegic drops. Spherical equivalent is calculated as sphere + (cylinder/2).
Time frame: Baseline, Month 3, Month 6, Month 9
Change in Visual Acuity
Visual acuity measured using LogMAR chart (Precision Vision) at distances of 4m, 2m, and 1m. LogMAR score recorded for each eye separately and both eyes together.
Time frame: Baseline, Month 3, Month 6, Month 9
Change in Contrast Sensitivity
Contrast sensitivity measured using Vistech chart (Precision Vision) at 1m distance. Scores recorded for each eye separately and both eyes together.
Time frame: Baseline, Month 3, Month 6, Month 9
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