Posterior Precortical Vitreous Pocket in Stickler Syndrome: A Report of Two Cases.

Stickler syndrome is a genetic disorder characterized by collagen abnormalities leading to various ocular manifestations, such as retinal detachment. We present two cases of siblings clinically diagnosed with Stickler syndrome who exhibited retinal detachment. Case 1, a seven-year-old girl, and case 2, her 14-year-old brother, both displayed severe myopia and other clinical signs consistent with Stickler syndrome. Despite their ages, neither case showed evidence of posterior precortical vitreous pocket (PPVP) on imaging or during surgical intervention. These findings suggest a potential relationship between collagen abnormalities and PPVP dysplasia in Stickler syndrome.

Spontaneous Regression and Separation of Idiopathic Epiretinal Membranes.

Epiretinal membranes (ERMs) typically remain stable or progressively worsen. Here, we report two rare cases of spontaneous ERM regression and one case of ERM separation. This is a case series of three patients. The patients' clinical data were collected and ERMs were evaluated with serial optical coherence tomographies (OCTs). Cases one and two were female patients presenting with floaters. Mild-to-moderate idiopathic ERM was diagnosed which spontaneously regressed over the following years without intervention and evidence of separation. Patients' vision was slightly decreased or remained stable, respectively. Case three was a female patient presenting with blurry vision. A mild ERM was diagnosed with vitreomacular traction (VMT) and a tiny macular hole. Over the following three months, ERM separation along with VMT release was evidenced on OCT. The macular hole healed simultaneously. Her vision improved from 20/70 to 20/30. The possibility of spontaneous regression of idiopathic ERMs should be a factor to consider in management. Further research must be done to determine the mechanism of this phenomenon.

[Role of vitreous in the pathogenesis of neovascular age-related macular degeneration]. / Die Rolle des Glaskörpers in der Pathogenese der exsudativen altersabhängigen Makuladegeneration.

Age-related changes in vitreous molecular and anatomic morphology begin early in life and involve two major processes: vitreous liquefaction and weakening of vitreo-retinal adhesion. An imbalance in these two processes results in anomalous posterior vitreous detachment (PVD), which comprises, among other conditions, vitreo-macular adhesion (VMA) and traction (VMT). VMA is more common in patients with neovascular age-related macular degeneration (nAMD) than age-matched control patients, with the site of posterior vitreous adherence to the inner retina correlating with location of neovascular complexes. The pernicious effects of an attached posterior vitreous on age-related macular degeneration (AMD) progression involve mechanical forces, enhanced fluid influx and inflammation in and between the retinal layers, hypoxia leading to an accumulation of vascular endothelial growth factor (VEGF) and other stimulatory cytokines, and probably an infiltration of hyalocytes. It has been shown that vitrectomy not only mitigates progression to end-stage AMD, but existing choroidal neovascularization regresses after surgery. Thus, surgical PVD induction during vitrectomy or by pharmacologic vitreolysis may be considered in non-responders to anti-VEGF treatment with concomitant VMA.

Utility of High-Resolution Ultrasonography in the Evaluation of Posterior Segment Ocular Lesions Using Sensitivity and Specificity.

Background: High-resolution Ultrasound (USG) provides good anatomical details of the ocular posterior segment and depicts the various pathological conditions affecting the ocular posterior segment, which helps ophthalmologists for choosing the best treatment options. This study aims to evaluate the utility of High-resolution Ultrasonography in the Evaluation of Posterior Segment Ocular lesions by using Sensitivity and Specificity. Materials and Methods: A hospital-based retrospective study enrolled 81 patients in a tertiary care hospital. Clinical and ophthalmological examinations were performed followed by USG of the orbits. B-mode USG was done with a 7.5-13 MHz linear probe. The final diagnosis was made by correlating the USG findings with clinical and ophthalmological examinations. Statistical analysis: Sensitivity, specificity, the positive predictive value, the negative predictive value, and the accuracy of B-scan USG were compared with the ophthalmological findings by using the Chi-square test. Results: Of 81 patients (n=48 males and n=33 females) with a mean age of 38.98 ± 16.48 [SD] years, posterior segment ocular lesions in association with cataracts were found in 27 (33.3%) patients, whereas 14 (51.9%) patients had posterior vitreous detachment (PVD), 10 (37%) patients had retinal detachment (RD), and 1 (3.7%) patient had choroidal detachment (CD). Posterior segment ocular pathologies were found in 17 (21%) patients with blunt ocular injuries, whereas 8 (47.1%) patients had PVD, 4 (23.5%) patients had RD and 4 (23.5%) patients had CD. The ocular USG had a sensitivity of 87.32%, specificity of 80%, and accuracy of 86.42% with a statistically significant difference between the USG findings and the Ophthalmology diagnosis of the posterior segment ocular abnormalities of a p-value of 0.0005. Conclusion: High-resolution ultrasound is one of the best and an easily available imaging modality for the evaluation of posterior segment ocular pathologies, especially in the presence of opaque ocular media.

A Novel Transcriptome Approach to the Investigation of the Molecular Pathology of Vitreous and Retinal Detachment.

Retinal detachment (RD) is one of the most common, sight-threatening ocular conditions requiring emergency intervention. Posterior vitreous detachment (PVD) occurs in the majority of an aging population whereby the vitreous body separates from the retina. It is well established that PVD is the common precursor to the most common forms of RD; however, it remains unknown why in most individuals PVD will cause no/few complications (physiological PVD) but in a small percentage will cause retinal tears and detachment (pathological PVD). Despite over 100 years of scientific research, the anatomical definitions of PVD and its pathogenesis remain controversial. Recent research has identified a novel cell population (laminocyte), present at significantly higher numbers in pathological PVD when compared to physiological PVD. We review and summarise the seven distinct clinical sub-groups of retinal breaks and focus on the role of the laminocyte in those secondary to PVD and the transcriptomic profile of this unique cell. Provisional whole transcriptome analysis using bulk RNA-Seq shows marked differentially expressed genes when comparing physiological PVD with PVD associated with RD. The limitations of bulk RNA-Seq are considered and the potential to address these using spatial transcriptomics are discussed. Understanding the pathogenesis of PVD-related retinal tears will provide a baseline for the development of novel therapeutic targets and prophylactic treatments.

[Modern understanding of structural and biochemical characteristics of the vitreous in eyes with normal and increased axial length]. / Sovremennye predstavleniya o strukturnykh i biokhimicheskikh svoistvakh steklovidnogo tela v norme i pri uvelichenii aksial'noi dliny glaza.

The review highlights the features of molecular, morphological and anatomical organization of the vitreous body in normal human eyes and in eyes with elongated anterior-posterior axis. The molecular structure of the vitreous consists of various types of collagen, glycosaminoglycans, glycoproteins and proteoglycans. The lowest concentration of collagen fibrils is in the central vitreous, so the structural changes of vitreous gel associated with attenuation of the vitreous body happen there much earlier and to a greater degree. Increased aggregation of collagen fibrils with age casuses an increase of liquid fractions of the vitreous with a concomitant decrease in gel volume. Similar processes occur earlier in eyes with axial myopia. Destructive processes in myopia increase progressively with axial elongation. As a result of vitreous collapse, vitreoretinal adhesion weakens and posterior vitreous detachment occurs.

Perfluoro-n-octane-assisted mega Weiss-ring technique for posterior vitreous detachment induction in retinal detachment.

Induction of posterior vitreous detachment (PVD) is one of the most critical steps for the success of retinal detachment (RD) surgery. Failure to completely remove the vitreous can result in re-detachments. We describe a novel technique to induce PVD. After core vitrectomy, perfluorocarbon liquid (PFCL) is injected. The vitreous on the posterior pole is gently stroked, with a diamond-dusted membrane scraper, to create a defect in it. This defect is gradually enlarged to create a ring of rolled out vitreous. The entire vitreous is removed in form of a sheet by lifting the edges of the ring using an internal limiting membrane peeling forceps. PFCL naturally slides into the potential space, gradually extending the vitreous detachment peripherally. With this technique, the vitreous sheet in case of RD can easily, effectively and safely be removed with this technique.