Posterior Segment Research Articles

Ocular Drug Delivery Routes: Diseases Overview and Advanced Administration Methods

The eye is anatomically divided into two: the anterior segment and the posterior segment. The anterior segment comprises structures located at the front of the eye, including the cornea, iris, ciliary body, pupil, aqueous humor, and lens. In contrast, the posterior segment encompasses structures located at the back of the eye, such as the vitreous, retina, choroid, macula, and optic nerves. Numerous diseases arise due to anomalies occurring within these ocular tissues. When formulating drugs for ocular conditions, it is crucial to consider the specific segment of the eye affected by the disease. Various routes of drug administration and dosage forms are available for delivering medications to the eye. These include topical forms such as solutions, emulsions, suspensions, ointments, and gels. Additionally, drugs can be administered through routes such as intravitreal, suprachoroidal, intracorneal, or subconjunctival. Furthermore, novel methods of drug delivery to the eye have emerged, including inserts, films, contact lenses, and microneedles. The aim of this review is to discuss innovative drug delivery systems and explain in detail the different routes of drug administration to the eye with examples from the current literature.

The effect of hand and body position on chest compression quality and rescuer fatigue in prone cardiopulmonary resuscitation

AimThis study aimed to compare the quality of compressions in supine cardiopulmonary resuscitation (CPR) and prone CPR by performing chest compressions on a manikin. Evaluating the effect of prone CPR using different hand and body position on the quality of manual chest compressions and fatigue of participants. MethodsAfter completing 2 min of chest compression in the supine position (Supine Group), 25 participants randomly performed three sets of 2-minutes chest compressions on a prone position manikin. Stand + hands overlapped Group: participants stood beside the patient bed with their hands overlapped and placed on the posterior segment of the thoracic spine between the scapulae, Straddle + hands separated Group: participants straddled the patient bed with their hands placed above the scapulae on both sides at the mid-chest level, and Straddle + hands overlapped Group: participants straddled the patient bed with their hands overlapping on the posterior segment of the thoracic spine between the scapulae. Subsequently, the quality of chest compressions and participants fatigue were assessed. ResultsChest compression depth ratio and mean chest compression depth (MCCD) were worse in the three prone CPR groups (Stand + hands overlapped Group: 0.0(0.0,15.6) %, 39.8 ± 1.3 mm; Straddle + hands separated Group: 1.4(0.0,11.7) %, 42.4 ± 1.2 mm; Straddle + hands overlapped Group: 0.0(0.0,9.2) %, 40.9 ± 1.2 mm) than in the Supine group (87.1(68.1,94.0) %; p < 0.001, 52.4 ± 0.4 mm; p < 0.001). In the three prone CPR groups, Straddle + hands separated Group had the greatest MCCD, lowest changes in heart rate (p = 0.018) and lowest changes in RPE scores (p < 0.001). There were no significant differences between the four groups in terms of mean chest compression rate, accurate chest compression rate ratio, or correct recoil ratio. ConclusionThis simulation-based study showed that the quality of chest compressions was worse in the prone position than in the supine position. When prone chest compressions were performed using different hand and body position, prone CPR performed by a participant straddling a hospital bed with hands placed above the scapula on either side at the mid-chest level provided higher-quality chest compressions and lower rescuer fatigue.

LGGL-03 TREATMENT OUTCOMES ON OPTIC GLIOMA: A CASE STUDY

Abstract 11 year old male presented in December 2021 with complaints of headache and visual impairment. On examination [he had] multiple freckles in the right axilla and cafe au lait lesions all over his body with largest being 3cm in the inguinal region. Pretreatment MRI showed minimally enhancing mass seen in the optic chiasm extending anteriorly into the distal optic nerves bilaterally and the optic tract posteriorly with extensive vasogenic edema along the optic pathway into the lateral thalamus and extending into the bilateral lentiform nuclei. H-MR spectroscopy of the mass demonstrated a choline peak. Findings in keeping with optic pathway glioma. The baseline fundoscopy showed a normal anterior segment, slightly pale disc on the posterior segment. The patient was commenced on weekly Vinblastine via chemo port. At 24 weeks of treatment patient was assessed MRI and fundoscopy. MRI showed a mild interval decrease in size of lobulated mass lesion involving the optic chiasma, bilateral optic nerves up to intraorbital segments and optic tracts. The lesion also involves the infundibular stalk and tuber cinereum. No interval change in hyperintense T2/FLAIR signal with no enhancement seen at the lateral geniculate bodies, hippocampi, bilateral lentiform nuclei and lateral thalami. He completed 72 weeks of Vinblastine with good clinical Response. NF 1 can cause tumors to form and optic nerve gliomas that may occur in about 15 percent of children with this disease in about 2/3 of the time the tumors stop growing and disappears however there are some tumors that may require treatment.

Normative Profile of Retinal Nerve Fiber Layer Thickness and Lamina Cribrosa-Related Parameters in a Healthy Non-Glaucoma Cynomolgus Monkey Colony.

The purpose of this study was to investigate the normal range of ophthalmic parameters and the correlations between systematic and ocular parameters and retinal nerve fiber layer (RNFL) thickness among a healthy non-glaucoma cynomolgus monkey colony. All included monkeys were given detailed ophthalmic examinations, including anterior and posterior segments. Furthermore, univariate and multivariate linear regression models were conducted to estimate the relationship between systemic and ophthalmic parameters and global RNFL thickness. A total of 349 non-glaucoma monkeys (18.69 ± 2.88 years old) were collected. The global RNFL thickness was 94.61 ± 10.13 µm, and sex-specific differences existed in all sectors. The decreasing trend of RNFL is as follows: inferotemporal, superotemporal, inferonasal, superonasal, temporal, and nasal. For lamina cribrosa (LC)-related parameters, cup depth (P < 0.01), LC thickness (P = 0.014), and Bruch's membrane opening (BMO) - minimum rim width 2 (P = 0.002) were greater in the male group. However, LC depth (P = 0.02), anterior laminar insertion depth-1 (P = 0.009), and mean anterior laminar insertion depth (P = 0.029) of female monkeys were greater than those of male monkeys. In multivariate linear regression, only older age was significantly related to reduced global RNFL thickness (P < 0.001). Our findings suggest the differences in RNFL thickness distribution and sex between non-glaucoma cynomolgus monkeys and humans. Therefore, the impact of this difference on outcomes should be fully considered in laboratory animal studies. Our findings are also significant in terms of developing a normative optical coherence tomography (OCT) database in nonhuman primates (NHPs). We found that the differences in RNFL thickness distribution and sex between non-glaucoma cynomolgus monkey colonies and humans should be thoroughly taken into account in laboratory animal studies.

Missed intralenticular foreign body – A cause of ocular inflammation

A 36-year-old male presented with a complaint of glare since 2 months. He had a history of trauma to the left eye with copper wire 2 years back. At presentation, the visual acuity was 20/20 in both eyes. Anterior-segment evaluation of the left eye revealed peripheral corneal scar, anterior uveitis, and iris hole. Dilated evaluation revealed sunflower cataract, focal cortical cataract, and an intralenticular foreign body (ILFB). The posterior segment was normal. Inflammation was controlled with topical steroids, followed by ILFB removal, phacoaspiration, and intraocular lens implantation. A thorough dilated ocular examination is essential to rule out an intraocular foreign body in all the cases of penetrating ocular trauma.

Measurement of transcranial Doppler insonation angles from three-dimensional reconstructions of CT angiography scans.

Blood velocities measured by Transcranial Doppler (TCD) are dependent on the angle between the incident ultrasound beam and the direction of blood flow (known as the Doppler angle). However, when TCD examinations are performed without imaging the Doppler angle for each vessel segment is not known. We have measured Doppler angles in the basal cerebral arteries examined with TCD using three-dimensional (3D) vessel models generated from computed tomography angiography (CTA) scans. This approach produces angle statistics that are not accessible during non-imaging TCD studies. We created 3D models of the basal cerebral arteries for 24 vasospasm patients. Standard acoustic windows were mapped to the specific anatomy of each patient. Virtual ultrasound transmit beams were generated that originated from the acoustic window and intersected the centerline of each arterial segment. Doppler angle measurements were calculated and compiled for each vessel segment. Doppler angles were smallest for the middle cerebral artery M1 segment (median 24.6°) and ophthalmic artery (median 25.0°), and largest for the anterior cerebral artery A2 segment (median 76.4°) and posterior cerebral artery P2 segment (median 75.8°). The ophthalmic artery had the highest proportion of Doppler angles that were less than 60° (99%) while the anterior cerebral artery A2 segment had the lowest proportion of Doppler angles that were less than 60° (10%). These angle measurements indicate the expected deviation between measured and true velocities in the cerebral arteries, highlighting specific segments that may be prone to underestimation of velocity.

Ocular and Adnexal Diseases in Human Immunodeficiency Virus-Infected Pregnant Women Attending HIV Clinics in Ibadan, Nigeria

Abstract Background: Human immunodeficiency virus (HIV) is a lentivirus. It is transmitted through sexual intercourse, shared intravenous drugs, contaminated needle use, blood transfusion, and mother-to-child transmission. Of the patients with HIV, 50%–75% have ocular manifestations and this may be the primary presentation. This study was carried out in two prevention of mother-to-child transmission (PMTCT)/HIV clinics. The aim was to determine the incidence, patterns of presentation, and determinants of ocular and adnexal diseases in HIV-positive pregnant women attending HIV clinics to develop an eye care protocol for them. Materials and Methods: The study was a cross-sectional study of HIV-positive pregnant women attending the PMTCT/HIV Clinics at University College Hospital and Adeoyo Maternity Teaching Hospital, Ibadan. Patients were interviewed using a structured questionnaire. Blood samples were taken for CD4+ count and viral load. The stage of the disease, type of antiretroviral therapy (ART), and the interval between HIV diagnosis and commencement of ART were recorded. Comprehensive ocular examination, which included visual acuity check unaided and with pinhole, lid, anterior segment examination with slit lamp and posterior segment examination with dilated binocular indirect ophthalmoscopy, was conducted. Statistical Package for Social Sciences version 23 was used to analyse the data. Results: A total of 153 pregnant women aged 23–42 years (mean, 33.5; standard deviation, ±5.6) were recruited. One hundred and fifteen (75.2%) of them were married in a monogamous setting. Multiple sexual partners (48.4%; n = 74—some women married in monogamous settings at the time of recruitment for this study had multiple sexual partners in the past) and the use of unsterilised objects (46.4%; n = 71) were major high-risk behaviours. Ocular and adnexal diseases were found in 81 (53%) participants. HIV-related ocular and adnexal diseases were found in 16 (10%) participants. Of the 16 HIV-related diseases, optic atrophy was found in seven (43.8%), presumed toxoplasmosis in three (18.7%), presumed cytomegalovirus retinitis in three (18.7%) lid warts in two (12.5%), and conjunctival microangiopathy in one (6.3%) participant. The association between HIV- related ocular and adnexal diseases and gestational age, CD4+ count, viral load and type of ART was not statistically significant. Conclusion: The few HIV-related findings in this study could be a result of the improved CD+ count/low viral load of most of the recruited participants. Ensuring that patients attending PMTCT/HIV clinic have at least one ocular examination during pregnancy by collaborating with eyecare professionals could ensure prompt detection and treatment of eye diseases, to improve the quality of life of HIV-positive pregnant women.

Clinical characteristics and visual outcomes of animal-induced ocular injuries: a prospective multicenter study in Iran.

Animal-induced ocular injuries represent an under-documented health problem that may pose significant visual complications. This study aimed to investigate the clinical characteristics and outcomes of ocular injuries caused by animals. This multicenter prospective study enrolled patients with a history of animal-induced ocular injuries presenting to the ophthalmology departments of two tertiary hospitals over a one-year period. All participants underwent comprehensive assessments by ophthalmologists, and the following data were collected: demographic information, animal species involved, injury details, pre- and post-treatment visual data, management strategies, and follow-up outcomes. Seventy-two patients (62.5% male) were included in the study. Insects were the most common species, causing 37.5% of ocular injuries. The type of animal involved was significantly associated with injury patterns (p < 0.0001), visual impairments at presentation (p < 0.05), and need for surgery (p < 0.001). Insects predominantly caused periorbital soft tissue injuries; birds primarily affected the anterior segment; dogs and cats mainly led to adnexal injuries; and equines often involved both anterior and posterior segments. Equine-related injuries resulted in the most severe visual impairments, requiring surgical interventions in all cases. At the same time, the majority of cases involved with other animal species experienced no visual impairment. The number of patients without visual impairment increased from 46 cases (63.9%) at the time of presentation to 58 (80.6%) at discharge after treatment. At follow-up, eight patients (11.1%) experienced complications, including traumatic cataract (n = 6, 8.3%), endophthalmitis (n = 3, 4.2%), corneal scarring (n = 1, 1.4%), and retinal detachment (n = 1, 1.4%). Rooster pecking was the leading cause of complications, including endophthalmitis and traumatic cataract. This study revealed that depending on the type of animal causing the injury, animal-induced ocular injuries present with diverse characteristics, requiring appropriate treatment approaches and potentially resulting in different outcomes. These findings may promote public awareness and improve preventive strategies and clinical guidelines development.

Ocular Manifestations in Children with Special Needs Presenting in a Tertiary Eye Hospital of Central Nepal

Background Children with special needs are at a substantially higher risk of visual impairment (VI) (10.5% compared with 0.16%) but also of ocular disorders of all types, including refractive errors and strabismus. VI and other potentially correctable ocular disorders are frequently unidentified in children with complex needs. Although assessment may be more challenging, identifying these potential additional barriers to learning and development may be critical.MethodsDetailed ophthalmic examination was carried out in all children with special needs presenting to the Pediatric OPD of Bharatpur Eye Hospital over 6 months (January to June 2023). Ophthalmic examination included case history, presenting distance visual acuity, cycloplegic refraction, binocular vision examination, anterior and posterior segment evaluation.ResultsOut of the total of 55 participants, mean age was 9.74 ± 5.07 years, majority were male 32 (58.18%). Quantitative visual acuity could be assessed only in 19 (34.55%) children, using picture chart 9 (16.36%) and Snellen chart 10 (18.18%). Strabismus 21 (38.18%) and refractive error 14 (25.45%) were the commonest visual disorders in our study children.Conclusions With patience, suitably adapted methods, visual assessment is feasible in the majority of children with special needs. It is hoped that the formulation of proper vision care guidelines at a national level may help in early detection and management of visual disorders in this special population and enhance their quality of life.

Результаты хирургического лечения проляпса в области заднего сегмента тазового дна у пациенток с раком молочной железы на фоне эндокринной терапии

The cause of pelvic organ ptosis in women is damage or weakening of the connective tissue and muscle structures of the pelvic floor, which normally serve as a supporting framework for pelvic organs and are estrogen-dependent. Most women with receptor-positive breast cancer are prescribed adjuvant endocrine therapy after surgery to suppress estrogen levels. The authors investigated the results of surgery of posterior pelvic floor segment prolapse in this category of patients (n = 50). The study was conducted in a comparative aspect with a group of patients who do not suffer from breast cancer (n = 50). For anatomical correction of prolapse, posterior colporaphy, anterior levatoroplasty or sphincterolevatoroplasty, resection of rectal mucosa prolapse using the STARR method, sacrocolporectopexy, depending on the pathology of certain structures of the pelvic floor, were performed. The evaluation of the treatment results was carried out after 3 years using clinical, radiological (defecography) and physiological methods (anorectal functional tests) studies. The authors showed that the symptoms of obstructive defecation and anal incontinence were less amenable to correction in patients with endocrine therapy. The authors concluded that it is necessary to prevent pelvic organ prolapse and the advantages of surgical correction of the initial forms of prolapse in this group of patients.

Histochemical Analysis and Distribution of Digestive Enzymes in the Gastrointestinal System of the European Barracuda Sphyraena sphyraena (Linnaeus, 1758).

In this study, we examined the gastrointestinal tract of the European barracuda (Sphyraena sphyraena) living in the Adriatic Sea near Dubrovnik, Croatia. The study aimed to identify the presence and distribution of four digestive enzymes: alkaline phosphatase, aminopeptidase, acid phosphatase, and non-specific esterase. We found that alkaline phosphatase activity was present in the brush border of the enterocytes in all the investigated intestinal segments. The activity of the alkaline phosphatase was the strongest in the pyloric caeca but strong only in the basal part of the intestinal villi in the anterior and middle intestinal segments. In the posterior intestinal segment, alkaline phosphatase had strong activity along the entire villi. The activity of acid phosphatase was weak in all the investigated parts of the intestine, except in the posterior part, where it was moderate. Aminopeptidase was detected in the brush border of the intestinal epithelium, with stronger activity in the pyloric caeca and anterior part of the intestine and weaker activity posteriorly. The activity of the non-specific esterase was moderate in the pyloric caeca and anterior part of the intestine, while it was weak in the posterior segment and the lamina propria in all parts of the digestive tract. Weak acid phosphatase activity was observed only in the lamina propria of the posterior part of the intestine. This study is the first to evaluate the activity of digestive enzymes in the European barracuda.

Central Retinal Artery Occlusion Following Intralesional Triamcinolone Injection for IgG4-related Orbital Disease.

The risk of blindness associated with periocular and facial injections is well documented. Previous cases describing vision loss following a recent periocular or facial injection have emphasized the importance of facial "danger zones." To date, the literature suggests that nearly half of all cases of central retinal artery occlusion in the setting of a recent periocular or facial injection involve an injection in or around the nose. Here, the authors report the second known case of central retinal artery occlusion following a triamcinolone injection to the lacrimal gland. A 30-year-old female with a diagnosis of IgG4-related disease underwent lacrimal gland debulking with an intralesional steroid injection. She noted OD vision loss immediately after surgery, with posterior segment examination demonstrating retinal whitening with a cherry-red spot and intra-arterial yellow-white plaques. This case serves as a reminder to clinicians regarding the risk of iatrogenic embolism following triamcinolone injections around the face with special attention drawn to the lacrimal gland.

Prevalence and associations of parapapillary scleral ridges: the Beijing Eye Study

PurposeTo explore the prevalence and associated factors of parapapillary scleral ridges (PSRs).MethodsOut of the cohort of the population-based Beijing Eye Study (n=3468 participants), the study included all eyes with an...

CRISPR/Cas9-mediated knockout of the abdominal-B homeotic gene in the global pest, fall armyworm (Spodoptera frugiperda).

The Homeotic complex (Hox) genes play a crucial role in determining segment identity and appendage morphology in bilaterian animals along the antero-posterior axis. Recent studies have expanded to agricultural pests such as fall armyworm (FAW), scientifically known as Spodoptera frugiperda J. E. Smith (Lepidoptera: Noctuidae), which significantly threatens global agricultural productivity. However, the specific role of the hox gene Sfabd-B in FAW remains unexplored. This research investigates the spatial and temporal expression patterns of Sfabd-B in various tissues at different developmental stages using quantitative real-time polymerase chain reaction (qRT-PCR). Additionally, we explored the potential function of the Sfabd-B gene located in the FAW genome using CRISPR/Cas9 technology. The larval mutant phenotypes can be classified into three subgroups as compared with wild-type individuals, that is, an excess of pedis in the posterior abdomen, deficient pedis due to segmental fusion and deviations in the posterior abdominal segments. Importantly, significant differences in mutant phenotypes between male and female individuals were also evident during the pupal and adult phases. Notably, both the decapentaplegic (dpp) and cuticular protein 12 (cp 12) genes displayed a substantial marked decrease in expression levels in the copulatory organ of male mutants and the ovipositor of female mutants compared with the wild type. These findings highlight the importance of Sfabd-B in genital tract patterning, providing a potential target for improving genetic control.

Explosive regeneration and anamorphic development of legs in the house centipede Scutigera coleoptrata

BackgroundRegenerating legs is advantageous for arthropods as their appendages exhibit crucial functional specializations. Many arthropods possess a ‘preferred breakage point’, where the appendage is most likely to break and where regeneration likely to occur, however, different taxa exhibit different levels of regenerative potential. Centipede appendage regeneration is categorized as 'progressive' or 'explosive'. In the later, the appendage is fully regenerated after one molt. This term was used for house centipedes that frequently lose their long legs. We chose Scutigera coleoptrata as a model to comprehensively investigate the process of leg appendotomy and regeneration as well as compare it with leg development in anamorphic instars.ResultsThe trochanter exhibits a preferred breakage point. Internally, it houses a three-layered diaphragm that effectively seals the lumen. In case of leg loss, the wound is quickly sealed. The epidermis detaches from the cuticle and muscles of the coxa get compacted, giving sufficient space for the regenerating leg. A blastema forms and the leg then grows in a coiled manner. The regenerating leg is innervated and syncytial muscles form. If the leg is lost in an early intermolt phase, progression of regeneration is slower than when a specimen is closer to the next molt. Instars of house centipedes can simultaneously develop and regenerate legs. The legs develop laterally on the posterior segments under the cuticle. As opposed to regeneration, the progression of leg development always follows the same temporal pattern throughout the entire intermolt phase.ConclusionSeveral factors are of major significance in house centipede leg regeneration. First, the ease with which they lose legs: the diaphragm represents an efficient tool for appendotomy. Moreover, the functional extension of the coxa provides space for a leg to be regenerated in. Lastly, the genetic predisposition allows them to regenerate legs within one molting cycle. This “package” is unique among land arthropods, and to this degree rare in marine taxa. Furthermore, observing leg regeneration and anamorphic leg development in parallel suggest that regeneration is most likely an epiphenomenon of development, and the differences are a requirement for the novel context in which re-development occurs.

Intravitreal steroid implants in the management of noninfectious intermediate and posterior uveitis

Abstract The management of intermediate and posterior uveitis poses a significant challenge of achieving adequate drug concentrations in the posterior segment over the chronic nature of the disease. Systemic agents seldom reach effective drug levels, and even with low maintenance or tapering doses, it is hard to avoid systemic toxicity. The use of intravitreal and periocular injections is often unable to prevent recurrences due to their short half-life. Since the emergence of intravitreal implants (Vitrasert, Retisert), it has become possible to circumvent these therapeutic challenges. A detailed review in the PubMed index yielded 155 articles, of which 22 were analyzed based on exclusion criteria. A recent shift from surgically sutured to minimally invasive injectable implants mainly indicated for noninfectious uveitis is evident from the literature. This review article also provides insights into dexamethasone (Ozurdex) and recent fluocinolone acetonide (Yutiq, Iluvien) implants with particular emphasis on their improved safety and efficacy. Dexamethasone implants favor the therapeutic goal of prevention of recurrences, whereas the use of fluocinolone implants helps to attain better visual outcomes due to their longer duration of action. Thus, the review provides recent literature supporting the role and indication of sustained release intravitreal implants in the management of noninfectious intermediate and posterior uveitis.

Fluocinolone acetonide 0.18-mg implant for treatment of recurrent inflammation due to non-infectious uveitis: a case series of 15 patients

IntroductionUncontrolled non-infectious uveitis affecting the posterior segment (NIU-PS) can lead to vision loss due to repeated bouts of inflammation and consequent tissue damage. Patients with chronic NIU-PS who experience recurrent uveitis after being treated with systemic and short-acting local corticosteroids may benefit from the sustained-release 0.18-mg fluocinolone acetonide implant (FAi).MethodsIn this case series, 18 eyes with chronic, recurrent NIU-PS and cystoid macular edema (CME) treated with the 0.18-mg FAi were analyzed retrospectively. Data on patient demographics, clinical history, previous and concomitant treatments for uveitis recurrence, time to and number of uveitis recurrences, intraocular pressure (IOP), central subfield thickness (CST), and visual acuity (VA) were collected and summarized.ResultsA majority of patients (14/15 [93%]) had a history of ocular surgery, largely cataract extraction, and all developed chronic and recurrent NIU-PS and CME. At baseline, patients had a mean age of 72 years (range: 46 to 93), were 53% male, and had a mean duration of NIU-PS of 3 years (range: 1 to 19). Patients were followed for an average of 16.5 months (range: 2 to 42.5 months) post FAi. Eleven of the 18 eyes (61%) had ≥ 5 recurrences of uveitis since diagnosis, with an average time to recurrence of approximately 12 weeks (range: 1 to 27). All eyes treated with the 0.18-mg FAi showed reduced NIU-PS recurrence and visual and anatomical improvement, as measured by VA and CST, respectively. Two eyes had an IOP elevation that was managed with topical therapy, and one eye was treated with topical prednisolone for additional inflammation management. Two eyes required adjunct therapy with short-acting intravitreal corticosteroids at 7 and 16 weeks for NIU-PS recurrence after 0.18-mg FAi insertion.ConclusionAfter receiving the 0.18-mg FAi, eyes with uncontrolled NIU-PS had sustained resolution of CME and inflammation with limited need for supplementary steroid drops or injections and minimal steroid class-specific adverse effects; none required incisional IOP-lowering surgery.

Corneal epithelial-stromal constructs to study differences associated with diabetes mellitus

Diabetes mellitus (DM) is a common metabolic disease associated with severe macrovascular and microvascular complications that influence nearly every tissue in the body, including the anterior and posterior segments of the eye. In the cornea, DM is associated with recurrent epithelial erosion and reduced wound-healing capacity, which increases the risk of corneal scarring. We previously developed a co-culture model of the cornea consisting of immortalized human corneal epithelial cells (hCE-TJ) overlaying a self-assembled stromal layer generated by human corneal fibroblasts (hCFs) over a 4-week period. In this study, we investigated epithelial-stromal constructs generated from hCFs derived from subjects with Type 1 (T1DM) or 2 diabetes (T2DM) compared to controls. We found that T2DM constructs exhibited a disrupted epithelium and a thicker, stratified stromal layer compared to controls or T1DM. Both T1DM and T2DM stromal constructs expressed lower expression of thrombospondin-1 in isolated extracellular vesicles (EVs) compared to controls with no significant difference observed in the presence of epithelial cells, suggesting that reduced provisional matrix secretion in the corneal stroma may be a factor that promotes delayed corneal wound healing in diabetes. The tetraspanins are established extracellular vesicle (EV) markers and include CD63, CD81, and CD9, and were highly expressed by EVs in all three cell types. Control corneal stromal fibroblasts produced more and larger EVs when compared to T1DM and T2DM hCF-derived EVs, supporting a role for altered cell-cell communication in the context of DM. Further characterization of EVs and their cargo is expected to aid in the development of targeted treatments to improve corneal wound healing.

Clinical Manifestations and Outcomes of Ocular Graft Versus Host Disease following Allogeneic Stem Cell Transplantation.

To evaluate clinical presentation of chronic ocular graft-versus-host disease (GVHD), laterality of presentation, and longitudinal changes in patients undergoing allogeneic stem cell transplantation. This is a retrospective longitudinal analysis of 60 eyes from 30 patients who had undergone hematopoietic stem cell transplantation. Demographic characteristics, clinical history, comorbidities, and other organ involvements were taken into account for analysis. We also undertook complete evaluation of the eyes, including cornea and anterior segment, posterior segment, Schirmer test, tear break-up time, ocular surface disease index, and intraocular pressure. The mean age of the patients was 34.3 11 years. The mean time for the diagnosis of ocular GVHD was 232.8 days (95% CI: 153.6, 311.9). The common findings at the first visit were bilateral blepharitis (n = 5, 17%), meibomitis (n = 4, 13%), and conjunctival congestion (n = 3, 10%). While bilateral cataract was present in one (3%) patient at the first visit, at 18 months, five (17%) patients had bilateral cataract and one (3%) patient had unilateral cataract. Grade 1 (n = 17), grade 2 (n = 9), and grade 3 (n = 4) superficial punctate epithelial erosions (SPEEs) were also observed at the first visit. However, SPEEs were seen in only 11 eyes at 18 months; all of these cases were grade 1 SPEEs. Long-term findings included cataract, telangiectasia, blepharospasm, conjunctival congestion, grade 1 SPEEs, corneal filaments, and tear film debris. Although the initial presentations were SPEEs, meibomitis, blepharitis, and conjunctival congestion, these inflammatory conditions were reduced over time with proper management. However, there was an increase in the proportion of patients with cataract. It is important to regularly monitor these patients in order to identify and manage the initial as well as the late ocular manifestations of chronic GVHD.

Correlation between optical coherence tomography angiography measured vessel density and retinal nerve fiber layer thickness in moderate primary open angle glaucoma cases and normal controls

: Aim of this study was to establish a correlation between findings obtained from Optical Coherence Tomography Angiography (OCT-A) and Retinal Nerve Fiber Layer (RNFL) thickness measurements in a series of moderate Primary Open Angle Glaucoma (POAG) cases and normal controls. In this observational cross-sectional study a total of 100 eyes were included, comprising 50 eyes with glaucoma and 50 control eyes without glaucoma. All participants underwent comprehensive anterior and posterior segment evaluations, intraocular pressure (IOP) measurement using Goldmann applanation tonometer, gonioscopy, visual field testing, and OCT imaging, which included OCT-A. The OCT-A imaging was performed using the RTvue XR Avanti by Optovue. Two types of analysis were conducted: a comparative analysis between the normal and glaucomatous groups using an unpaired t-test to assess differences in RNFL thickness and vessel density values, and a correlation analysis within each group to examine the strength of correlation between RNFL loss and reduction in vascular density. The results showed a significant reduction in vessel density index in all quadrants of glaucomatous eyes compared to normal eyes. Moreover, this reduced vessel density was found to be significantly correlated with the reduction in RNFL thickness in glaucoma patients. Specifically, the uperior and inferior quadrants exhibited the strongest correlation with each other. The severity of vascular compromise demonstrated a significant correlation with the extent of retinal nerve fiber loss in patients with glaucoma. OCT-A can serve as a valuable adjunct in the diagnosis of glaucoma and monitoring its progression.