An interventional study of subthreshold treatment with micropulsed laser in Macular Edema, Inherited Retinal Dystrophy and Laser Retinopathy, sponsored by Fondazione G.B. Bietti, IRCCS. Recruiting at 1 site in Italy. Open to participants aged 18 Years to 80 Years. Per ClinicalTrials.gov, last updated 2025-02-28.
Sponsored by Fondazione G.B. Bietti, IRCCS · Not applicable, Interventional, and Treatment
The purpose of this study is to investigate whether subthreshold treatment with micropulsed laser can be effective in resolving macular edema in patients with inherited retinal dystrophy.
Visits will be performed after 1, 3, 6, 9, 12, 18, and 24 months after treatment. Laser treatment will be performed on the day of the first visit, and its repetition at subsequent visits between months 3 and 12 will be evaluated.
Evaluations of treatment effects will include:
Primary endpoint.
BACKGROUND:
Degenerative diseases of the visual system classified as rare and, in particular, those affecting the retina (known as Inherited retinal dystrophies, IRDs) cause very severe functional deficits. Their onset is in many cases particularly early with a consequent visual impact of extreme severity. They constitute a heterogeneous group from a clinical point of view, but in all of them the loss of photoreceptors causes progressive vision loss that can result in complete blindness.
These pathologies can be complicated by the presence of cataracts, epiretinal membrane and macular oedema (10-50%), resulting in a worsening of visual acuity. While surgical treatment is applicable for the first two complications, the treatment of macular oedema can make use of several options. Oral or topical diuretics (Acetazolamide) are still the first therapeutic approach and, if oedema persists despite treatment, intravitreal corticosteroid injection has been used in various reports. The injection of anti-Vascular Endothelial Growth Factor (VEGF) drugs and vitrectomy have also been proposed but with conflicting results. The use of topical non-steroidal drugs has been studied and proven to be valuable, although inferior to diuretic treatment in terms of visual recovery. The use of intravitreal corticosteroids is also not without possible further complications such as ocular hypertension and early onset of cataracts.
Despite some improvement in retinal oedema by taking the above-mentioned diuretics, relapses can be observed at the end of therapy, reason for taking longer periods (>12 weeks) of therapy. However, the same chronic continuation of diuretic therapy is not always desirable considering its possible adverse events such as tingling sensation, malaise, altered taste sensation and gastrointestinal disorders.
RATIONALE:
The application of the micropulsed subthreshold retinal laser to reduce retinal oedema in various diseases (diabetic oedema, central serous chorioretinopathy, age-related macular degeneration and retinal vein occlusion) has recently gained wide acceptance.
Retinal threshold refers to the tendency of the laser to cause tissue bleaching resulting in retinal cell death, the term sub-threshold implies that the laser uses such a small amount of energy that it does not cause irreversible damage to retinal structures. The term 'micropulsed' derives from the fact that the laser does not use a continuous wave but has a sub-100% duty cycle and the use of 'off' times is what distinguishes this type of laser from conventional lasers and allows the tissue to cool down, preventing laser-induced retinal damage.
The main characteristics of this type of laser are therefore that it does not cause visible retinal damage and that it has therapeutic effects.
One theory of how this type of laser works is through the action of the molecular protective mechanisms of the Heat Shock Protein (Hsp) family in the retina, including protein chaperone activity, stabilisation of the cytoskeleton and prevention of apoptosis mainly through inhibition of cytochrome C release through the phenomenon of 'resetting'. Another theory hypothesized the activation of leucocyte recruitment or remodeling of the extracellular matrix in the choroid and retina. Possible mechanisms of increased trophic factors (CNTF and FGF-2)14 and up-regulation of other factors (MMP-2, MMP-3, TNFα and Nos2) are covered.
TRIAL DESIGN:
Prospective, interventional, single-centre, open-label study involving consecutive enrolment (see sample size in section "Statistics") of patients with macular oedema in retinal dystrophies.
Each patient referred to the Outpatient Clinical and Research Center of Neuro-ophthalmology and Genetic and Rare Diseases with IRD and macular oedema treated for 3 months with diuretics and draining food supplements and without improvement of macular oedema or increase of the same (reduction of post-therapy CRT ≤20% compared to pre-therapy CRT) will be duly informed about the therapeutic option of this study protocol. After verification of the criteria for inclusion in the study and after signing of the informed consent, the patient will be considered eligible for treatment with micropulsed laser by the physicians of the Clinical and Research Center of Neuro-ophthalmology and Genetic and Rare Diseases and Medical Retina. The patient enrolled in the study will be clinically analysed with the instrumentation indicated below at regular intervals (screening/baseline, follow-up 1 [FU1] (1 month), FU2 (3 months), FU3 (6 months), FU4 (9 months), FU5 (12 months), FU6 (18 months) and FU7 (24 months).
756 studies on the registry are indexed under Macular Edema; 65 are open to participants now.
This study's planned enrollment of 10 is below the median of 56 across 584 interventional studies indexed under Macular Edema.
Browse Macular Edema studies →Fondazione G.B. Bietti, IRCCS is the lead sponsor of 19 studies on the registry; 7 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Laser treatment will be performed in patients with macular edema in IRD (experimental arm) who: * underwent treatment with diuretics or nutritional drainage products for 3 months and subsequent 'wash-out' of one month 17,18 and had no reduction in macular oedema, in terms of central retinal thickness, of at least 20% compared with the initial assessment * they have had an intravitreal injection of anti-VEGF or steroids, and after 3 months there is no reduction in central retinal thickness (CRT) of at least 20% compared to the initial assessment * have after 3 months a thickness reduction \<10% compared to baseline assessment, following initial treatment with micropulsed laser, and may be candidates for repeating treatment; * are not eligible for diuretic therapy due to the presence of comorbidities.
Device: subthreshold treatment with micropulsed laser
The laser instrument used is the Q 577® Laser System, Iridex, wavelength 577 yellow. The standard pattern used is: * Power: 5% Duty Cycle * Power 250 mw * Pulse duration 200 ms * Spot size 100 micron * Pattern spacing 0.0 confluente, griglie 7x7
assessment of significative change in retinal oedema compared to baseline
assessment of central retinal thickness by macular SD-OCT
Time frame: up to 24 months
To study changes in visual acuity between before and after treatment
LogMAr visual acuity values
Time frame: up to 24 months
To study the retinal function in the macular area before and after treatment.
response amplitude density, measured in nV/dg2 and analysed using multifocal electroretinogram, assessing the amplitude in 5 concentric rings centred on the fovea.
Time frame: up to 24 months
To study the retinal perfusion of the macular area by OCT-angiography before and after treatment.
vascular density (expressed as Retinal Vessel Density) before and after treatment, using OCT-angiography
Time frame: up to 24 months
Plan to share: Yes — At the end of the research, within 6 months after the end of the study, a Final Clinical Report of the study containing clinical comments based on the data generated by the statistical processing will be prepared by the Investigator and/or delegated person. This report will be structured as an \"integrated statistical clinical report\" containing the clinical comments based on the data generated by the statistical report.
Supporting information: Clinical study report
Time frame: Six months after the end of the study
Access criteria: On demand
Started Sep 2023 (actual). Primary completion is estimated for Jul 2025, 22 months after the start.
Of 46 non-industry interventional studies with no phase under Macular Edema, half reached primary completion within 21 months of starting (the median), counting those still running; a quarter within 10 and three quarters within 42. This study's planned 22 months is close to that.
Counting every sponsor, half of 50 studies reached it within 21 months; a quarter within 9 and three quarters within 37.
How these figures are worked out, and which studies are left out of them.
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Fondazione G.B. Bietti, IRCCS