Extracellular vesicles (EVs), a diverse group of cell-derived exocytosed particles, are pivotal in mediating intercellular communication due to their ability to selectively transfer biomolecules to specific cell types. EVs, composed of proteins, nucleic acids, and lipids, are taken up by cells to affect a variety of signaling cascades. Research in the field has primarily focused on stem cell-derived EVs, with a particular focus on mesenchymal stem cells, for their potential therapeutic benefits. Recently, tissue-specific EVs or cell type-specific extracellular vesicles (CTS-EVs), have garnered attention for their unique biogenesis and molecular composition because they enable highly targeted cell-specific communication. Various studies have outlined the roles that CTS-EVs play in the signaling for physiological function and the maintenance of homeostasis, including immune modulation, tissue regeneration, and organ development. These properties are also exploited for disease propagation, such as in cancer, neurological disorders, infectious diseases, autoimmune conditions, and more. The insights gained from analyzing CTS-EVs in different biological roles not only enhance our understanding of intercellular signaling and disease pathogenesis but also open new avenues for innovative diagnostic biomarkers and therapeutic targets for a wide spectrum of medical conditions. This review comprehensively outlines the current understanding of CTS-EV origins, function within normal physiology, and implications in diseased states.

To evaluate ocular surface health in obstructive sleep apnea syndrome (OSAS) and to investigate the tendency of these patients toward dry eyes. Fifty patients who underwent polysomnography and were diagnosed with OSAS and 50 normal control subjects were compared with respect to ocular surface disease index (OSDI), Schirmer I test and tear film break-up time (TBUT) values. Patients were grouped as mild (n=15, 30%), moderate (n=15, 30%) and severe (n=20, 40%) according to apnea-hypopnea index values. The right eyes of patients were included in both groups. OSDI values were as follows: control group, 18.7±8.5; mild OSAS group, 40.2±2.8; moderate OSAS group, 48.5±2.2 and severe OSAS group, 62.7±2.3 (p<0.001). TBUT values were as follows: control group, 12.3±4.9; mild OSAS group, 8.2±4.7; moderate OSAS group, 5.8±2.1 and severe OSAS group, 4.2±3.7 (p<0.001). Schirmer values were as follows: control group, 18±6.1 mm; mild OSAS group, 12.9±6.7 mm; moderate OSAS group, 8.5±5.2 mm and severe OSAS group, 7.9±4.7 mm (p<0.001). Patients with OSAS seem to have a tendency toward dry eyes. Clinicians should be aware of dry eye development in these patients.

Purpose: To assess intraobserver and interobserver reproducibility of the measurement of choroidal thickness by using enhanced depth imaging optical coherence tomography (EDI-OCT). Methods: A prospective, cross-sectional study was performed at Gazi University Ophthalmology Department. The macular areas of the right eyes of 110 healthy volunteers with no ophthalmic or systemic disease were recruited. Choroidal thickness was measured at the fovea and at 1000-μm intervals from the foveal center in both temporal and nasal directions. Each examiner measured choroidal thickness 30 days after the first measurement to assess intraobserver variability. Interobserver and intraobserver reproducibility were described by intraclass correlation coefficient (ICC) and coefficient of variation (CV). Results: The mean age was 44.0 ± 14.7 years (range 18-70 years). The mean choroidal thickness at the fovea was 315.5 ± 78.6. All the parameters evaluated were highly reproducible. Intraobserver CV of choroidal thickness measurements ranged from 24.76% to 35.74%, and the CV of subfoveal choroidal thickness was 24.92. The intraobserver and interobserver intraclass correlation coefficient was greater than 0.90 for all the parameters. Repeatability was slightly better at locations not exceeding 400 μm. Conclusions: Choroidal thickness measurements obtained by EDI-OCT showed good repeatability for healthy Turkish subjects; EDI-OCT examinations of choroid are reliable in healthy eyes.

Purpose: To assess the effect of intense regulated pulse light (E-Eye; E-Swin, France) on the treatment of meibomian gland dysfunction. Setting: Health Sciences University, Ankara Numune Training and Research Hospital, Department of Ophthalmology. Methods: A total of 26 patients underwent intense pulsed light treatment (E-Eye; E-Swin), with homogeneously sequenced five light pulses delivered to one eye at 1, 15, and 45 days following baseline evaluation. At each visit, subjective clinical parameters (ocular surface disease index questionnaire and standard patient evaluation of eye dryness questionnaire) and objective clinical parameters (Schirmer I test scores, tear break-up times, Oxford grading, lid margin abnormality score, secretion quality and expressibility degree) were recorded. The subjective and objective parameters at Days 15 and 45 were compared with baseline values. Results: Patients underwent three sessions of intense pulsed light treatment. Schirmer test and tear break-up time improved significantly from baseline to Day (D) 45 (8.53 ± 4.31 mm vs 12.6 ± 3.14 mm, 4.53 ± 1.33 sn vs 11.07 ± 2.87 sn, p = 0.003 and p < 0.001). Ocular surface disease index and standard patient evaluation of eye dryness scores improved from baseline to D15 and baseline to D45 (all with p < 0.05). All the subjects reported reduced symptoms by D45. There were no cases of adverse ocular effects. There was no significant change in Oxford grading, lid margin abnormality score, secretion quality, and expressibility degree. Conclusions: Intense regulated pulse light seems a safe treatment procedure for meibomian gland dysfunction, improving tear film quality and reducing symptoms of dry eye.