Background: To evaluate a fully automated vascular density (VD), skeletal density (SD) and fractal dimension (FD) method for the longitudinal analysis of retinal vein occlusion (RVO) eyes using projection-resolved optical coherence tomography angiography (OCTA) images and to evaluate the association between these quantitative variables and the visual prognosis in RVO eyes.
Methods: Retrospective longitudinal observational case series. Patients presenting with RVO to Creteil University Eye Clinic between October 2014 and December 2018 and healthy controls were retrospectively evaluated. Group 1 consisted of central RVO (CRVO) eyes, group 2 consisted of eyes with branch RVO (BRVO) and group 3 of healthy control eyes. OCTA acquisitions (AngioVue RTVue XR Avanti, Optovue, Inc., Freemont, CA) were performed at baseline and last follow up visit. VD, SD, and FD analysis were computed on OCTA superficial and deep vascular complex (SVC, DVC) images at baseline and final follow up using an automated algorithm. Logistic regression was performed to find if and which variable (VD, SD, FD) was predictive for the visual outcome.
Results: Forty-one eyes, of which 21 consecutive eyes of 20 RVO patients (13 CRVO in group 1, 8 BRVO in group 2), and 20 eyes of 20 healthy controls were included. At the level of SVC, VD and FD were significantly lower in RVO eyes compared to controls (P<0.0001 and P=0.0008 respectively). Best-corrected visual acuity (BCVA) at last follow-up visit was associated with baseline VD (P=0.013), FD (P=0.016), and SD (P=0.01) at the level of the SVC, as well as with baseline FD at the DVC level (P=0.046).
Conclusions: Baseline VD, SD, and FD are associated with the visual outcome in RVO eyes. These parameters seem valuable biomarkers and may help improve the evaluation and management of RVO patients.
Abstract: Navigation technology in ophthalmology, colloquially called “eye-tracking”, has been applied to various areas of eye care. This approach encompasses motion-based navigation technology in both ophthalmic imaging and treatment. For instance, modern imaging instruments use a real-time eye-tracking system, which helps to reduce motion artefacts and increase signal-to-noise ratio in imaging acquisition such as optical coherence tomography (OCT), microperimetry, and fluorescence and color imaging. Navigation in ophthalmic surgery has been firstly applied in laser vision corrective surgery and spread to involve navigated retinal photocoagulation, and positioning guidance of intraocular lenses (IOL) during cataract surgery. It has emerged as one of the most reliable representatives of technology as it continues to transform surgical interventions into safer, more standardized, and more predictable procedures with better outcomes. Eye-tracking is essential in refractive surgery with excimer laser ablation. Using this technology for cataract surgery in patients with high preoperative astigmatism has produced better therapeutic outcomes. Navigated retinal laser has proven to be safer and more accurate compared to the use of conventional slit lamp lasers. Eye-tracking has also been used in imaging diagnostics, where it is essential for proper alignment of captured zones of interest and accurate follow-up imaging. This technology is not routinely discussed in the ophthalmic literature even though it has been truly impactful in our clinical practice and represents a small revolution in ophthalmology.
Abstract: Submacular haemorrhage (SMH) is a sight threatening complication that can occur in exudative age related macular degeneration (AMD), but has been described to occur more frequently in eyes with polypoidal choroidal vasculopathy (PCV). Left untreated, SMH carries a grave visual prognosis. Thus, expedient diagnosis and effective management of this complication is of paramount importance. The treatment strategies for SMH include (I) displacement of blood from the fovea, usually by injection of an expansile gas; (II) pharmacologic clot lysis such as with recombinant tissue plasminogen activator (rtPA); and (III) treatment of the underlying choroidal neovascularization (CNV) or PCV, such as with anti-vascular endothelial growth factor (anti-VEGF) agents. These three strategies have been employed in isolation or in combination, some concurrently and others in stages. rtPA has demonstrable effect on the liquefaction of submacular clots but there are remaining uncertainties with regards to the dose, safety and the timing of initial and repeat treatments. Potential side effects of rtPA include retinal pigment epithelial toxicity, increased risk of breakthrough vitreous haemorrhage and systemic toxicity. In cases presenting early, pneumatic displacement alone with anti-VEGF may be sufficient. Anti-VEGF monotherapy is a viable treatment option particularly in patients with thinner SMH and those who are unable to posture post pneumatic displacement.
Background and Objective: Subthreshold laser therapy has emerged as a therapeutic alternative to traditional laser photocoagulation for certain ophthalmic diseases including central serous chorioretinopathy (CSCR), diabetic macular edema (DME), macular edema secondary to branch retinal vein occlusion (BRVO), and age-related macular degeneration (AMD). The objective of this paper is to review and discuss the clinical applications of subthreshold laser and the mechanisms of different subthreshold laser techniques including subthreshold micropulse laser (SMPL), selective retina therapy (SRT), subthreshold nanosecond laser (SNL), endpoint management (EpM), and transpupillary thermotherapy (TTT).
Methods: A narrative review of English literature and publicly available information published before November 2021 from literature databases and computerized texts. We discuss the currently available subthreshold laser systems and the advancements made to perform different subthreshold laser techniques for various ophthalmic diseases. We highlight various clinical studies and therapeutic techniques that have been conducted to further understand the effectiveness of subthreshold laser in the clinical setting. We conclude the article by covering emerging subthreshold laser systems that are currently being developed for future clinical use. The PubMed database was utilized for peer-reviewed articles and pertinent information on subthreshold systems was cited from publicly available online websites covering specific systems.
Key Content and Findings: Various subthreshold laser systems have been developed to treat certain retinal diseases. Several systems are currently in development for future clinical applications.
Conclusions: While conventional laser photocoagulation has been effective in treating various retinal diseases, subthreshold laser systems aim to provide a therapeutic effect without visible signs of damage to the underlying tissue. This technology may be particularly effective in treating macular disorders. Further clinical studies are needed to evaluate their role in the management of retinal diseases.
