Background: Sodium iodate (SI) is a chemical widely applied to induce retina degeneration in animal models. SI treatment caused formation of rosettes/folds in the outer nuclear layer (ONL) of the rat retina, but it was previously unclear whether SI also forms rosettes in mice. In addition, SI induced retina degeneration was never addressed in non-separate sclerochoroid/retina pigment epithelium/retina whole mount. Here we displayed features of retina degeneration including rosette formation in mice and developed a morphological analytic assessment using sclerochoroid/retina pigment epithelium/retina whole mounts.
Methods: SI was intraperitoneally injected in Sprague-Dawley (SD) rats and C57BL/6J mice using a single dose (50 mg/kg) or with a dose range (10 to 50 mg/kg) in BALB/C mice. Rat retinas were investigated up to 2-week post-injection by histology and whole mounts, and mouse retinas were investigated up to 3-week post-injection by histology, fluorescent staining of sections and/or sclerochoroid/retina pigment epithelium/retina whole mounts for the morphological evaluations of the SI-induced retina damage.
Results: SI-induced retina damage caused photoreceptor (PR) degeneration and rosettes/folds formation, as well as retina pigment epithelium degeneration and inward migration. It displayed mixed nuclei from choroid to PRs, due to layer disorganization, as shown by single horizontal images in the sclerochoroid/retina pigment epithelium/retina whole mounts. Measurement of the PR rosette area induced by SI provided a quantitative, morphological evaluation of retina degeneration.
Conclusions: The method of non-separate sclerochoroid/retina pigment epithelium/retina whole staining and mount allows us to observe the integral horizontal view of damage from sclera to PR layers, which cannot be addressed by using sectioned and separate whole mount methods. This method is applicable for morphological evaluation of retina damage, especially in the subretinal layer.
Background: Retinal degeneration is a common feature of several retinal diseases, such as retinitis pigmentosa and age-related macular degeneration (AMD). In this respect, experimental models of photo-oxidative damage reproduce faithfully photoreceptor loss and many pathophysiological events involved in the activation of retinal cell degeneration. Therefore, such models represent a useful tool to study the mechanisms related to cell death. Their advantage consists in the possibility of modulating the severity of damage according to the needs of the experimenter. Indeed, bright light exposure could be regulated in both time and intensity to trigger a burst of apoptosis in photoreceptors, allowing the study of degenerative mechanisms in a controlled fashion, compared to the progressive and slower rate of death in other genetic models of photoreceptor degeneration.
Methods: Here, an exemplificative protocol of bright light exposure in albino rat is described, as well as the main outcomes in retinal function, photoreceptor death, oxidative stress, and inflammation, which characterize this model and reproduce the main features of retinal degeneration diseases.
Discussion: Models of photo-oxidative damage represent a useful tool to study the mechanisms responsible for photoreceptor degeneration. In this respect, it is important to adapt the exposure paradigm to the experimental needs, and the wide range of variables and limitations influencing the final outcomes should be considered to achieve proper results.
Trial Registration: None.
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.
Background: Bacillary layer detachment (BALAD) is a phenomenon characterized by fluid accumulation at the myoid region of the inner photoreceptor segments identifiable on optical coherence tomography (OCT) imaging. This finding has been recently described in patients with diverse primary diagnoses which share the common feature of serous exudation in the posterior pole. However, thus far there have been very few reports in the literature of BALAD in patients with posterior scleritis.
Case Description: A 16-year-old male presented with unilateral vision changes that acutely worsened overnight to significant unilateral vision loss. He was eventually diagnosed with idiopathic posterior scleritis with associated BALAD on OCT. Similar to other reported cases of BALAD, he experienced anatomic restoration of the outer retina followed by good visual recovery after treatment with high dose steroid, ultimately with complete recovery of both retinal anatomy and vision within 4 months.
Conclusions: This case provides further evidence that posterior scleritis can be a cause of BALAD. The rapid presentation and excellent visual and anatomical outcome of this case is entirely consistent with known descriptions of BALAD in a variety of other conditions, further supporting the categorization of BALAD as an entity which retinal specialists should be able to recognize as distinct from other forms of intraretinal fluid, retinal detachment, and retinoschisis.
Background: To investigate the outcome of cataract surgery in patients with legal blindness defined as best-corrected visual acuity (BCVA) of 20/1,000 or lower and to determine factors influencing the visual outcome in these patients.
Methods: Medical records of 68 eyes of 62 patients diagnosed with legal blindness and underwent cataract surgery were reviewed. The study population was divided into 3 groups based on types of cataracts (Group A: posterior subcapsular cataract, Group B: mature or brunescent cataract, and Group C: cataract combined with other ocular diseases). Data including demographics, predisposing factors, BCVA before and 6 months after surgery and post-operative complications were collected and analyzed.
Results: Mean preoperative logMAR BCVA was 1.88±0.24, 2.24±0.26 and 1.96±0.31 in Groups A, B and C, respectively (P=0.003). The postoperative BCVA was 0.49±0.35, 0.51±0.47 and 0.90±0.53 in Groups A, B and C, respectively (p=0.003). Significant improvement in BCVA was shown in all 3 groups (P<0.001 in Groups A and B and, P=0.001 in Group C). There was significant difference in the amount of visual improvement among the 3 groups, P<0.001). Although there was no significant difference in the amount of visual improvement between group A and C (P=0.379), significantly higher visual improvement was achieved in group B compared with group A (P=0.012) and C (P=0.001).
Conclusions: Cataract surgery should be encouraged for patients with legal blindness, even in the presence of other ocular disease. Significant visual recovery was observed in all the groups, particularly in those with mature or brunescent cataract.
Background: Bacillary layer detachment (BALAD) is a phenomenon characterized by fluid accumulation at the myoid region of the inner photoreceptor segments identifiable on optical coherence tomography (OCT) imaging. This finding has been recently described in patients with diverse primary diagnoses which share the common feature of serous exudation in the posterior pole. However, thus far there have been very few reports in the literature of BALAD in patients with posterior scleritis.
Case Description: A 16-year-old male presented with unilateral vision changes that acutely worsened overnight to significant unilateral vision loss. He was eventually diagnosed with idiopathic posterior scleritis with associated BALAD on OCT. Similar to other reported cases of BALAD, he experienced anatomic restoration of the outer retina followed by good visual recovery after treatment with high dose steroid, ultimately with complete recovery of both retinal anatomy and vision within 4 months.
Conclusions: This case provides further evidence that posterior scleritis can be a cause of BALAD. The rapid presentation and excellent visual and anatomical outcome of this case is entirely consistent with known descriptions of BALAD in a variety of other conditions, further supporting the categorization of BALAD as an entity which retinal specialists should be able to recognize as distinct from other forms of intraretinal fluid, retinal detachment, and retinoschisis.
