This study is a randomized controlled trial designed to evaluate whether branched-chain amino acid (BCAA) supplementation can help slow the progression of myopia in young adults. Eligible participants will be randomly assigned to receive either BCAA supplementation combined with standard spectacle correction or standard spectacle correction with a matching placebo. The intervention period will last approximately six months. Participants will undergo regular follow-up examinations, including measurements of visual acuity, refractive error, axial length, intraocular pressure, and other ocular parameters. Additional assessments such as ocular imaging (including OCTA), physical examinations, and blood tests will also be performed to evaluate eye health and metabolic indicators. The main purpose of this study is to investigate whether BCAA supplementation can provide a safe and effective nutritional strategy to slow myopia progression and improve understanding of the relationship between amino acid metabolism and ocular growth.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
TRIPLE
Enrollment
108
Participants will receive oral branched-chain amino acids (BCAA), including leucine, isoleucine, and valine, as a dietary supplement in addition to standard spectacle correction. The intervention is administered daily for approximately 6 months. The supplement is a commercially available nutritional product obtained via cross-border e-commerce channels and is not intended as a therapeutic drug. The aim is to evaluate the effect of BCAA supplementation on myopia progression and ocular biometric parameters.
Zhongda Hospital, Southeast University No. 87 Dingjiaqiao Road, Gulou District, Nanjing, Jiangsu Province, China
Nanjing, Jiangsu, China
Change in axial length
Axial length (AL) will be measured in both eyes using optical biometry at baseline, 3 months, and 6 months. The primary outcome is the change in axial length from baseline to 6 months, comparing the BCAA supplementation plus spectacle correction group with the spectacle correction only group.
Time frame: Baseline to 6 months
Change in spherical equivalent refractive error
Cycloplegic spherical equivalent (SE) will be measured using autorefractometry under cycloplegia at baseline, 3 months, and 6 months. The primary outcome is the change in spherical equivalent refractive error from baseline to 6 months, comparing the BCAA supplementation group with the control group.
Time frame: Baseline to 6 months
Superficial retinal vessel density
Superficial retinal vessel density will be measured in both eyes using OCTA in foveal, parafoveal, and perifoveal regions. Sectoral measurements (temporal, superior, nasal, and inferior) will be obtained, and the final value will be calculated as the mean of all regions, reported as a percentage (%).
Time frame: Baseline and 6 months
Deep retinal vessel density
Deep retinal vessel density will be measured in both eyes using OCTA across ETDRS regions. Sectoral measurements will be obtained, and the final value will be calculated as the mean of all regions, reported as a percentage (%).
Time frame: Baseline and 6 months
Choriocapillaris perfusion density
Choriocapillaris perfusion will be measured in both eyes using OCTA across foveal, parafoveal, and perifoveal regions. Sectoral measurements will be obtained, and the final value will be calculated as the mean of all regions, reported as a percentage (%).
Time frame: Baseline and 6 months
Retinal perfusion density
Retinal perfusion density will be measured in both eyes using OCTA across ETDRS regions, including full retinal perfusion and large-vessel-excluded perfusion. Sectoral measurements will be obtained, and the final value will be calculated as the mean of all regions, reported as a percentage (%).
Time frame: Baseline and 6 months
Family Ocular History
Definition: Baseline refractive status of parents based on self-reported highest degree of myopia in either eye. Variable type: Categorical Measurement: Self-reported parental myopia status categorized as none, low (≤300°), moderate (300-600°), and high (≥600°).
Time frame: Baseline
Nutritional Supplement Use
Definition: Baseline information on participants' use of any nutritional or dietary supplements. Variable type: Binary (Yes/No) Measurement: Self-reported use of dietary or nutritional supplements (Yes/No).
Time frame: Baseline
Protein Allergy History
Definition: Baseline assessment of whether participants have a documented or self-reported history of protein allergy. Variable type: Binary (Yes/No) Measurement: Self-reported history of protein allergy (Yes/No).
Time frame: Baseline
Parental Education Level
Parental education level at baseline, self-reported via structured questionnaire. Education levels are categorized as: primary school or below, junior/high school, university, and master's degree or above.Variable Type：Categorical
Time frame: Baseline
Daily Screen Time
Average daily time spent using electronic devices (including television, mobile phone, computer, and projection screen) over the past week, assessed by questionnaire. Variable type: Categorical.
Time frame: Baseline
Eye Rest and Break Behavior
Definition: Frequency of eye breaks during near work activities. Variable type: Categorical Measurement: Self-reported duration of continuous near work before rest (≤30 min, 30-60 min, 1-2 h, 2-3 h, ≥3 h).
Time frame: Baseline
Sleep Duration
Definition: Average daily sleep duration over the past week. Variable type: Continuous Measurement: Self-reported average sleep time (hours and minutes per day).
Time frame: Baseline
Staple food intake frequency
Frequency and quantity of staple food intake, including rice, wheat-based products, corn products, mixed beans, tubers, and fried flour-based foods, assessed using a semi-quantitative food frequency questionnaire.
Time frame: Baseline
Protein-rich food intake frequency
Frequency and quantity of protein-rich food consumption, including soybeans and soy products, meat (pork, beef, lamb, poultry), aquatic products (fish, shrimp, shellfish), eggs, and dairy products, assessed using a semi-quantitative food frequency questionnaire.
Time frame: Baseline
Vegetable intake frequency
Frequency and quantity of vegetable intake, including dark green vegetables, red/orange vegetables, purple vegetables, and light-colored vegetables, assessed using a semi-quantitative food frequency questionnaire.
Time frame: Baseline
Fruit intake frequency
Frequency and quantity of fruit intake, including pome fruits, citrus fruits, stone fruits, berries, melons, and tropical fruits, assessed using a semi-quantitative food frequency questionnaire.
Time frame: Baseline
Dairy product intake frequency
Frequency and quantity of dairy product consumption, including liquid milk, milk powder, and yogurt, assessed using a semi-quantitative food frequency questionnaire.
Time frame: Baseline
Snack and sugary food intake frequency
Frequency and quantity of intake of snacks and sugary foods, including baked goods, nuts, processed snacks, sweets, and sugar-sweetened beverages, assessed using a semi-quantitative food frequency questionnaire.
Time frame: Baseline
Temporal Superior RNFL Thickness
Peripapillary retinal nerve fiber layer (RNFL) thickness in the temporal superior (TU) sector measured by optical coherence tomography angiography (OCTA), reported in micrometers (µm).
Time frame: Baseline and 6 months
Superior Temporal RNFL Thickness
Peripapillary RNFL thickness in the superior temporal (ST) sector measured by OCTA, reported in micrometers (µm).
Time frame: Baseline and 6 months
Superior Nasal RNFL Thickness
Peripapillary RNFL thickness in the superior nasal (SN) sector measured by OCTA, reported in micrometers (µm).
Time frame: Baseline and 6 months
Nasal Superior RNFL Thickness
Peripapillary RNFL thickness in the nasal superior (NU) sector measured by OCTA, reported in micrometers (µm).
Time frame: Baseline and 6 months
Nasal Inferior RNFL Thickness
Peripapillary RNFL thickness in the nasal inferior (NL) sector measured by OCTA, reported in micrometers (µm).
Time frame: Baseline and 6 months
Inferior Nasal RNFL Thickness
Peripapillary RNFL thickness in the inferior nasal (IN) sector measured by OCTA, reported in micrometers (µm).
Time frame: Baseline and 6 months
Inferior Temporal RNFL Thickness
Peripapillary RNFL thickness in the inferior temporal (IT) sector measured by OCTA, reported in micrometers (µm).
Time frame: Baseline and 6 months
Temporal Inferior RNFL Thickness
Peripapillary RNFL thickness in the temporal inferior (TL) sector measured by OCTA, reported in micrometers (µm).
Time frame: Baseline and 6 months
Global Average Peripapillary RNFL Thickness
Global average peripapillary retinal nerve fiber layer (RNFL) thickness measured by optical coherence tomography angiography (OCTA), calculated as the mean thickness across all peripapillary regions, and reported in micrometers (µm).
Time frame: Baseline and 6 months
Optic Disc Area
Optic disc area measured in both eyes using optical coherence tomography angiography (OCTA), reported in square millimeters (mm²).
Time frame: Baseline and 6 months
Neuroretinal Rim Area
Neuroretinal rim area measured in both eyes using OCTA, reported in square millimeters (mm²).
Time frame: Baseline and 6 months
Optic Cup Volume
Optic cup volume measured in both eyes using OCTA, reported in cubic millimeters (mm³).
Time frame: Baseline and 6 months
Cup-to-Disc Ratio
Cup-to-disc ratio measured in both eyes using OCTA, defined as the ratio of optic cup diameter to optic disc diameter (unitless).
Time frame: Baseline and 6 months
Vertical Cup-to-Disc Ratio
Vertical cup-to-disc ratio measured in both eyes using OCTA (unitless).
Time frame: Baseline and 6 months
Horizontal Cup-to-Disc Ratio
Horizontal cup-to-disc ratio measured in both eyes using OCTA (unitless).
Time frame: Baseline and 6 months
Peripapillary Temporal Superior Sector Vessel Density
Peripapillary microvascular vessel density in the temporal superior (TU) sector measured in both eyes using optical coherence tomography angiography (OCTA), reported as vessel density percentage (%).
Time frame: Baseline and 6 months
Peripapillary Superior Temporal Sector Vessel Density
OCTA-derived vessel density in the superior temporal (ST) peripapillary sector in both eyes,reported as vessel density percentage (%).
Time frame: Baseline and 6 months
Peripapillary Superior Nasal Sector Vessel Density
OCTA-derived vessel density in the superior nasal (SN) peripapillary sector in both eyes,reported as vessel density percentage (%).
Time frame: Baseline and 6 months
Peripapillary Nasal Superior Sector Vessel Density
OCTA-derived vessel density in the nasal superior (NU) peripapillary sector in both eyes,reported as vessel density percentage (%).
Time frame: Baseline and 6 months
Peripapillary Nasal Inferior Sector Vessel Density
OCTA-derived vessel density in the nasal inferior (NL) peripapillary sector in both eyes,
Time frame: Baseline and 6 months
Peripapillary Inferior Nasal Sector Vessel Density
OCTA-derived vessel density in the inferior nasal (IN) peripapillary sector in both eyes,reported as vessel density percentage (%).
Time frame: Baseline and 6 months
Peripapillary Inferior Temporal Sector Vessel Density
OCTA-derived vessel density in the inferior temporal (IT) peripapillary sector in both eyes,reported as vessel density percentage (%).
Time frame: Baseline and 6 months
Peripapillary Temporal Inferior Sector Vessel Density
OCTA-derived vessel density in the temporal inferior (TL) peripapillary sector in both eyes,reported as vessel density percentage (%).
Time frame: Baseline and 6 months
Global Peripapillary Vessel Density
Mean peripapillary microvascular vessel density calculated across all peripapillary sectors in both eyes using OCTA,reported as vessel density percentage (%).
Time frame: Baseline and 6 months
Full Macular Retinal Thickness
Full retinal thickness in the macular region measured in both eyes using optical coherence tomography angiography (OCTA), including foveal, parafoveal, and perifoveal regions across temporal, superior, nasal, and inferior sectors.
Time frame: Baseline and 6 months
Macular Inner Retinal Layer Thickness
Inner retinal layer thickness in the macular region measured in both eyes using OCTA, assessed at foveal, parafoveal, and perifoveal regions across four quadrants (temporal, superior, nasal, inferior).
Time frame: Baseline and 6 months
Macular Outer Retinal Layer Thickness
Outer retinal layer thickness in the macular region measured in both eyes using OCTA, including foveal, parafoveal, and perifoveal regions across temporal, superior, nasal, and inferior sectors.
Time frame: Baseline and 6 months
Foveal Avascular Zone Area
Foveal avascular zone (FAZ) area measured in both eyes using optical coherence tomography angiography (OCTA).
Time frame: Baseline and 6 months
FAZ-300 Superficial Capillary Plexus Perfusion Density
Perfusion density in a 300 μm annular region surrounding the FAZ in the superficial capillary plexus measured using OCTA.
Time frame: Baseline and 6 months
FAZ-300 Deep Capillary Plexus Perfusion Density
Perfusion density in a 300 μm annular region surrounding the FAZ in the deep capillary plexus measured using OCTA.
Time frame: Baseline and 6 months
FAZ-300 Full Retinal Perfusion Density
Perfusion density in a 300 μm annular region surrounding the FAZ across full retinal layers measured using OCTA.
Time frame: Baseline and 6 months
Alanine Aminotransferase (ALT)
Serum alanine aminotransferase (ALT) measured in fasting venous blood using standard laboratory methods. Values will be analyzed as continuous variables and categorized as normal or abnormal based on clinical reference ranges.
Time frame: Baseline and 6 months
Aspartate Aminotransferase (AST)
Serum AST measured using standard laboratory methods in fasting venous blood. Values will be analyzed as continuous variables and categorized as normal or abnormal based on clinical reference ranges.
Time frame: Baseline and 6 months
Total Bilirubin (TBil)
Serum total bilirubin measured in fasting venous blood. Values will be analyzed as continuous variables and categorized as normal or abnormal based on clinical reference ranges.
Time frame: Baseline and 6 months
Serum Creatinine (Scr)
Serum creatinine measured in fasting venous blood using standard laboratory methods. Values will be analyzed as continuous variables and categorized as normal or abnormal based on clinical reference ranges.
Time frame: Baseline and 6 months
Blood Urea Nitrogen (BUN)
BUN measured in fasting venous blood using standard laboratory methods. Values will be analyzed as continuous variables and categorized as normal or abnormal based on clinical reference ranges.
Time frame: Baseline and 6 months
Uric Acid (UA)
Serum uric acid measured in fasting venous blood using standard laboratory methods. Values will be analyzed as continuous variables and categorized as normal or abnormal based on clinical reference ranges.
Time frame: Baseline and 6 months
Fasting Plasma Glucose (FPG)
Fasting plasma glucose measured in fasting venous blood using standard laboratory methods. Values will be analyzed as continuous variables and categorized as normal or abnormal based on clinical reference ranges.
Time frame: Baseline and 6 months
Total Cholesterol (TC)
Serum total cholesterol measured in fasting venous blood using standard laboratory methods. Values will be analyzed as continuous variables and categorized as normal or abnormal based on clinical reference ranges.
Time frame: Baseline and 6 months
Triglycerides (TG)
Serum triglycerides measured in fasting venous blood using standard laboratory methods. Values will be analyzed as continuous variables and categorized as normal or abnormal based on clinical reference ranges.
Time frame: Baseline and 6 months
High-Density Lipoprotein Cholesterol (HDL-C)
HDL cholesterol measured in fasting venous blood using standard laboratory methods. Values will be analyzed as continuous variables and categorized as normal or abnormal based on clinical reference ranges.
Time frame: Baseline and 6 months
Low-Density Lipoprotein Cholesterol (LDL-C)
LDL cholesterol measured in fasting venous blood using standard laboratory methods. Values will be analyzed as continuous variables and categorized as normal or abnormal based on clinical reference ranges.
Time frame: Baseline and 6 months
Sex of Participants
Participant sex recorded at baseline using structured questionnaire.
Time frame: Baseline
Age of Participants
Age calculated from date of birth at baseline using structured questionnaire.
Time frame: Baseline
Ethnicity of Participants
Ethnicity recorded at baseline using structured questionnaire.
Time frame: Baseline
Body Mass Index (BMI)
BMI calculated from weight and height measured at baseline.Units：kg/m², Type：Continuous
Time frame: Baseline
Household Residence
Household residence (urban/rural) recorded at baseline using structured questionnaire.Type：Categorical
Time frame: Baseline
Annual Household Income
Annual household income recorded at baseline using structured questionnaire.Type : categorical
Time frame: Baseline
Study Pressure Level
Self-reported level of study pressure and workload, assessed by questionnaire with four levels ranging from low to high. Variable type: Categorical.
Time frame: Baseline
Unhealthy Visual Habits
Presence of unhealthy visual habits (e.g., reading under strong sunlight, using screens in dark environments, improper posture during near work), assessed by multiple-choice questionnaire. Variable type: Categorical (multiple response).
Time frame: Baseline
Lighting Conditions During Nighttime Near Work
Lighting conditions used during near-work activities after dark (e.g., desk lamp, ceiling light), assessed by questionnaire. Variable type: Categorical.
Time frame: Baseline
Moderate-to-Vigorous Physical Activity Duration
Average daily duration of moderate-to-vigorous physical activity (e.g., brisk walking, running, jumping rope, cycling) over the past week, assessed by questionnaire. Variable type: Categorical.
Time frame: Baseline
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