Study Results
The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.
Basic Information
Get a concise snapshot of the trial, including recruitment status, study phase, enrollment targets, and key timeline milestones.
COMPLETED
90 participants
OBSERVATIONAL
2015-03-15
2016-01-15
Brief Summary
Review the sponsor-provided synopsis that highlights what the study is about and why it is being conducted.
Researchers will compare eye findings in patients who have previously used Bonzai with a healthy control group to see if there are ocular effects.
Detailed Description
Dive into the extended narrative that explains the scientific background, objectives, and procedures in greater depth.
SCs and relevant metabolites in urine samples were screened with a direct ELISA kit (K2 Enzyme Immunoassay, Immunalysis Corp., Pomona, CA, USA). This kit was able to detect relevant metabolites, such as JWH-018, JWH-073, and AM-2201, with a cut-off level of 20 ng/mL and over for positive results. Exposures to classical cannabinoids, ecstasy, amphetamines, opioids, and ethylene glycol were also screened.
Regarding SC use, the patients were asked about the duration and the last time of use. In addition, the previous use of other substances was questioned in detail.
Ophthalmic Assessments All eyes underwent ophthalmic examinations, including autorefraction, best-corrected visual acuity (BCVA) testing, biomicroscopy, non-contact IOP measurement, and dilated fundus examination.
An experienced technician performed spectral-domain optical coherence tomography (SD-OCT) imaging of all eyes following pupil dilatation (1% tropicamide) and systolic/diastolic blood pressure measurements (SBP/DBP). All SD-OCT assessments were conducted between 14:00 and 16:00 to minimize the potential effect of diurnal variation. Only high-quality SD-OCT images with a signal strength index (SSI) greater than 50 were sent for analysis. The parafoveal retinal thickness (parafoveal RT) and central foveal thickness (CFT), CT, peripapillary RNFL thickness, and macular GCC thickness measurements were performed with an RTVue-100 OCT device (Optovue Inc., Fremont, US), which had a 5 µm axial image resolution with a speed of 27,000 A-scans per second.
We preferred the ONH map protocol for examining the RNFL parameters. This protocol creates a RNFL thickness map based on measurements around a circle 3.45 mm in diameter centred on the ONH. The protocol for the GCC scan was based on examining a square grid (7 × 7 mm) on the central macula after centring 1 mm temporal to the macula. The average, superior, and inferior values displayed by the device were studied for the mean GCC and mean RNFL parameters.
Segmental divisions were recorded with the MM5 protocol of the inbuilt software, characterized by a 5 × 5 mm2 grid of 11 horizontal and 11 vertical lines with 668 A-scans and a 3 × 3 mm2 inner grid of 6 horizontal and 6 vertical lines with 400 A-scans for the retinal thickness of a 1 mm diameter CFT. The CT was measured by cross-sectioning through the foveolar centre line, characterized by an 8 mm width, with 1024 A-scans captured on the chorioretinal mode (these settings enable enhanced depth imaging along with contrast and brightness tuning). The line was rotated horizontally and vertically so that manual measurements were taken first at the central foveola and then 750 µm apart in the nasal, temporal, superior, and inferior directions with the ruler function, using a line extending from the posterior edge of the retinal pigment epithelium to the choroidoscleral junction.
The choroidal structure was analysed using the method previously described by Agrawal et al., and all collected images were processed and analysed using the open-source and publicly available ImageJ software (version 1.50a, freely available at http://imagej.nih.gov/ij/; National Institutes of Health \[NIH\], Bethesda, MD). According to this method, the image was first binarized using the Niblack auto-local thresholding function. This provided a clear visualization of the choroidoscleral interface while also enabling the precise selection of a region of interest, such as the total subfoveal choroidal area (TA). A fovea-centred, 1500 μm wide, nasal-to-temporal subfoveal choroidal area was manually selected using the polygon selection tool. The dark pixels representing the luminal area (LA) were selected using the colour threshold tool, and the residual light pixels were considered the stromal area (SA). The subfoveal CVI was calculated as the ratio of the LA to the TA. Manual measurements (CT and CVI) were carried out by the same experienced investigator blinded to the groups. Each measurement was repeated twice, and the mean of the two measurements was used in the analysis.
Statistical analysis Statistical analysis was conducted with software (SPSS 22.0 Version, IBM Corporation, New York, USA). Descriptive statistics were stated as the mean, standard deviation (SD), or median (Med), the interquartile range (Q1-Q3), and the frequency and ratio (%) values, where appropriate. The distribution of normality was evaluated for each parameter with the Kolmogorov-Smirnov test. Parametric (for normal distribution) or non-parametric tests were applied as appropriate. A parametric analysis of variance (ANOVA) with a post hoc Tukey test or a non-parametric Kruskal-Wallis test with a post hoc Bonferroni-corrected Mann-Whitney U test was used to analyse the independent variables. The chi-square test was used to analyse the qualitative data. Correlations of choroidal thickness measurements with parameters relevant to SC use were studied using the Spearman test.
Conditions
See the medical conditions and disease areas that this research is targeting or investigating.
Keywords
Explore important study keywords that can help with search, categorization, and topic discovery.
Study Design
Understand how the trial is structured, including allocation methods, masking strategies, primary purpose, and other design elements.
CASE_CONTROL
CROSS_SECTIONAL
Study Groups
Review each arm or cohort in the study, along with the interventions and objectives associated with them.
Control Group
Eyes of subjects with no history of use of any substance
No interventions assigned to this group
Seronegative Synthetic Cannabinoids Group
Eyes of patients declaring no present use of any substance and as verified by three consecutive negative urine toxicology tests performed two weeks apart
No interventions assigned to this group
Seropositive Synthetic Cannabinoids Group
Eyes of patients with positive urine toxicology tests proving present use of synthetic cannabinoids
No interventions assigned to this group
Eligibility Criteria
Check the participation requirements, including inclusion and exclusion rules, age limits, and whether healthy volunteers are accepted.
Inclusion Criteria
* 30 eyes of age-matched 30 male healthy control subjects
Exclusion Criteria
2. chronic ocular disease, such as uveitis or glaucoma
3. history of previous ocular surgery
4. systemic disease, such as diabetes mellitus or hypertension
5. systemic or topical drug use that may influence vascular tone, such as topical anti-glaucomatous and systemic anti-hypertensive medications
6. refraction in spherical equivalent (SE) ± 1 dioptre (D) out of range. -
MALE
Yes
Sponsors
Meet the organizations funding or collaborating on the study and learn about their roles.
Bezmialem Vakif University
OTHER
Responsible Party
Identify the individual or organization who holds primary responsibility for the study information submitted to regulators.
Principal Investigators
Learn about the lead researchers overseeing the trial and their institutional affiliations.
Ismail Umut Onur, MD
Role: STUDY_DIRECTOR
Bakirkoy Dr. Sadi Konuk Educational and Research Hospital
Locations
Explore where the study is taking place and check the recruitment status at each participating site.
Bakirkoy Dr. Sadi Konuk Educational and Research Hospital
Istanbul, , Turkey (Türkiye)
Countries
Review the countries where the study has at least one active or historical site.
References
Explore related publications, articles, or registry entries linked to this study.
Agrawal R, Salman M, Tan KA, Karampelas M, Sim DA, Keane PA, Pavesio C. Choroidal Vascularity Index (CVI)--A Novel Optical Coherence Tomography Parameter for Monitoring Patients with Panuveitis? PLoS One. 2016 Jan 11;11(1):e0146344. doi: 10.1371/journal.pone.0146344. eCollection 2016.
Kunduraci MS, Kirik F, Onur IU, Onur OS, Karsidag C, Yigit FU, Erkiran M. Ocular effects of synthetic cannabinoids: a case-control study. Eye (Lond). 2025 Jan;39(1):94-101. doi: 10.1038/s41433-024-03381-x. Epub 2024 Oct 8.
Other Identifiers
Review additional registry numbers or institutional identifiers associated with this trial.
2015/56
Identifier Type: -
Identifier Source: org_study_id