Age-related reduction in the functional properties of adult stem cells located in the peripheral region of human retinal pigment epithelium.

PURPOSE: Adult stem cells (SCs) with self-renewal and multilineage potential have been reported upon culturing human retinal pigment epithelial (RPE) cells. The current study aimed to identify the location of SCs in human RPE and to elucidate the age-related changes. METHODS: Peripheral, equatorial, and central RPE cells from donors of three age groups were analyzed for their sphere-forming, clonal, and label-retaining cell properties. Furthermore, native human RPE flatmounts were immunostained for SC and proliferating cell markers. RESULTS: Cells with higher sphere-forming and clonal ability were identified only in young donors (<30 years) and were restricted to the periphery. Upon culturing, cells from peripheral and equatorial regions had the label-retaining cell (LRC) property. With aging, the LRCs were restricted to the periphery and were reduced. In young donors, Ki67+ proliferating cells were not observed in native RPE. However, such cells were observed in the peripheral RPE of older donors correlating with the need for regeneration. The native RPE cells were negative for SC marker expression. CONCLUSION: The above findings highlighted the presence of SCs with the ability to proliferate in the peripheral RPE and a reduction in these functional properties of SCs with aging.

Couching of cataractous lens in microphthalmic eyes with irido-fundal coloboma: revisiting the historical technique.

PURPOSE: Cataract surgery in microphthalmic eyes is challenging due to anatomical restraints, hard bulky nucleus. This series aims to evaluate the safety and efficacy of couching of intraocular lens in irido-fundal coloboma with microphthalmos. SETTING: Tertiary care centre in South India. DESIGN: Retrospective non-comparative study in eyes with irido-fundal coloboma, corneal diameter < 7 mm and brown cataract. Visual acuity less than 6/60 in other eye. METHODS: Anterior chamber entry made, zonules broken and lens dislocated into the vitreous cavity in a controlled manner. Baseline Clinico-demographic details, corrected distance visual acuity (CDVA), Intra-ocular pressure (IOP), corneal diameter, axial length, lens status and post-surgery CDVA, IOP and complications recorded and followed up for atleast 6 months. RESULTS: Fifteen eyes of 15 subjects were evaluated with a mean age 49.4 ± 10.9 years. At baseline, mean IOP 14.5 ± 3.8 mmHg, mean axial length 19.3 ± 0.5 mm, mean corneal diameter was 6.5 ± 0.34 mm and CDVA 2 logMAR which improved to 1.5 logMAR at 3 months (p value 0.002). Transient spike in IOP in 33.3% subjects was medically managed with no significant difference in IOP (p > 0.05) at baseline (14.5 ± 3.8 mmHg), 3 months post-surgery (16 ± 2.8 mmHg) and 6 months post-surgery (14.9 ± 2.5 mmHg). One patient underwent re-couching. No other major complications were noted. CONCLUSION: Couching of cataractous lens is an effective and safe method in microphthalmic eyes with irido-fundal coloboma as last resort procedure, where no other surgical procedure may work. It provides an ambulatory gain of visual acuity in previously non-ambulatory subjects. Corneal measurements help in determining the subset of patients where couching offers viable option.

Detection of microRNAs expression signatures in vitreous humor of intraocular tuberculosis.

BACKGROUND: MicroRNA (miRNA) expression analysis has been shown to provide them as biomarkers in several eye diseases and has a regulatory role in pathogenesis. However, miRNA expression analysis in the vitreous humor (VH) of intraocular tuberculosis (IOTB) is not studied. Thus, we aim to find miRNA expression signatures in the VH of IOTB patients to identify their regulatory role in disease pathogenesis and to find them as potential biomarkers for IOTB. METHODS AND RESULTS: First, we profiled miRNAs in VH of three IOTB and three Macular hole (MH) samples as controls through small-RNA deep sequencing using Illumina Platform. In-house bioinformatics analysis identified 81 dysregulated miRNAs in IOTB. Further validation in VH of IOTB (n = 15) compared to MH (n = 15) using Real-Time quantitative PCR (RT-qPCR) identified three significantly upregulated miRNAs, hsa-miR-150-5p, hsa-miR-26b-5p, and hsa-miR-21-5p. Based on the miRNA target prediction, functional network analysis, and RT-qPCR analysis of target genes, the three miRNAs downregulating WNT5A, PRKCA, MAP3K7, IL7, TGFB2, IL1A, PRKCB, TNFA, and TP53 genes involving MAPK signaling pathway, PI3K-AKT signaling pathway, WNT signaling pathway, Cell cycle, TGF-beta signaling pathway, Long-term potentiation, and Sphingolipid signaling pathways, have a potential role in disease pathogenesis. The ROC analysis of RT-qPCR data showed that hsa-miR-150-5p with AUC = 0.715, hsa-miR-21-5p with AUC = 0.789, and hsa-miR-26b-5p with AUC = 0.738; however, the combination of hsa-miR-21-5p and hsa-miR-26b-5p with AUC = 0.796 could serve as a potential biomarker for IOTB. CONCLUSIONS: This study provides the first report on miRNA expression signatures detected in VH for IOTB pathogenesis and also provides a potential biomarker for IOTB.

Comparative proteomics of proliferative diabetic retinopathy in people with Type 2 diabetes highlights the role of inflammation, visual transduction, and extracellular matrix pathways.

Purpose: To explore the vitreous humor proteome from type 2 diabetes subjects with proliferative diabetic retinopathy (PDR) in the Indian population. Methods: We performed mass spectrometry-based label-free quantitative analysis of vitreous proteome of PDR (n = 13) and idiopathic macular hole (IMH; control) subjects (n = 14). Nine samples of PDR and 10 samples of IMH were pooled as case and control, respectively, and compared. Four samples each of PDR and IMH were analyzed individually without pooling to validate the results of the pooled analysis. Comparative quantification was performed using Scaffold software which calculated the fold changes of differential expression. Bioinformatics analysis was performed using DAVID and STRING software. Results: We identified 469 proteins in PDR and 517 proteins in IMH vitreous, with an overlap of 172 proteins. Also, 297 unique proteins were identified in PDR and 345 in IMH. In PDR vitreous, 37 proteins were upregulated (P < 0.05) and 19 proteins were downregulated compared to IMH. Protein distribution analysis clearly demonstrated a separation of protein expression in PDR and IMH. Significantly upregulated proteins included fibrinogen gamma chain, fibrinogen beta chain, and carbonic anhydrase 1 and downregulated proteins included alpha-1-antitrypsin, retinol-binding protein 3, neuroserpin, cystatin C, carboxypeptidase E and cathepsin-D. Conclusion: Diabetic retinopathy pathogenesis involves proteins which belong to inflammation, visual transduction, and extracellular matrix pathways. Validation-based experiments using enzyme-linked immunosorbent assay (ELISA) or western blotting are needed to establish cause and effect relationships of these proteins to the disease state, to develop them as biomarkers or drug molecules.

Bilateral Central Retinal Vein Occlusion in a Neonate.

AIM: To report the management of a neonate who presented with simultaneous bilateral central retinal vein occlusion (CRVO) secondary to septicemia. DESIGN: Case Report. RESULTS: A full-term infant was treated for neonatal sepsis with thrombocytopenia. He presented with poorly dilating pupil, disc edema, dilated retinal veins, perivascular exudation, retinal hemorrhages in all four quadrants radiating from the optic nerve to the ora serrata (no Roth spots), with cystoid macular edema (CME) in both the eyes. His TORCH serology was negative and peripheral blood film was normal. He was diagnosed as presumptive bilateral inflammatory CRVO with CME secondary to septicemia. He received bilateral intravitreal bevacizumab injections. After the injection, his pupils dilated completely while retinal hemorrhages and CME reduced. CONCLUSION: CRVO may present as a rare complication in neonates suffering from septicemia. Apart from the systemic treatment, aggressive ocular treatment is needed to salvage the eyes with severe ischemia.

Unilateral retinitis pigmentosa associated with cystoid macular oedema.

Retinitis pigmentosa (RP) is the most common inherited cause of blindness in the developed world, characterized by night blindness, reduced central vision and constricted visual field; however, unilateral RP is extremely rare. Macular complications such as cystoid macular oedema (CME), macular holes and vitreoretinal interface alterations, such as epiretinal membranes, have been reported in advanced stages. We describe a patient with unilateral RP presenting with CME, a rare occurrence.

Surgical management of full-thickness macular hole following Nd:YAG laser hyaloidotomy for pre-macular haemorrhage in a patient with anaemic retinopathy.

Pre-macular haemorrhage (PMH) can cause profound visual loss. Some surgeons prefer neodymium-doped yttrium aluminium garnet (Nd:YAG) hyaloidotomy as the first line of treatment due to being an easy technique and having a high success rate. However, the use of high energy close to the fovea can lead to various macular complications. We present a case of a patient who presented with PMH secondary to anaemic retinopathy. He underwent Nd:YAG laser hyaloidotomy, but developed a full-thickness macular hole. He further underwent vitrectomy and a type 1 closure was achieved. However, the visual gain was poor due to the large hole size and the collateral thermal damage. The hole may not close spontaneously, thus requiring surgical intervention. The surgical outcome of these holes depends on the size of the hole and the collateral thermal damage caused during the laser procedure.

A report on a series of nanophthalmos with histopathology and immunohistochemistry analyses using light microscopy.

We aimed to study the histopathological and immunohistochemistry features in clinically diagnosed cases of nanophthalmos using light microscopy. This was an observational comparative study. We enrolled four eyes of four consecutive patients with nanophthalmos and visually significant cataract, who underwent cataract surgery with prophylactic posterior sclerostomy. Histological analysis of the excised scleral tissue was done and compared with age-matched cadaver controls between January 2021 and October 2021. Hematoxylin and Eosin (H&E) stains were used for histological analysis, and was further supplemented with immunohistochemistry (IHC) and immunofluorescence (IF) analyses using a simple light microscope. The immunostained sections were analyzed using confocal microscope for the fibronectin expression level. The main outcome measure was demonstration of histological changes of sclera in nanophthalmic eyes undergoing cataract surgery. Light microscopic features of nanophthalmos revealed thick fibers with fraying and lightly stained cores, irregular serrated edges, and randomly interspersed fibroblasts compared to regular arrangement of collagen fibers seen in cadaver controls. Immunohistochemistry analysis with anti-fibronectin antibody showed strong positivity in clustered fibers in nanophthalmos, and less intense diffuse staining in cadaver tissue. Histoclinical correlation was observed in one nanophthalmic scleral tissue with axial length less than 17 mm showing severe disorganization with diffuse collagenization, loss of fibrillary architecture compared to another specimen with axial length more than 17 mm. Simple, cost-effective light microscopy using basic stains was effective in identifying the characteristic histopathological features in nanophthalmic eyes, and this was further highlighted by immunohistochemistry and immunofluorescence analyses.

Clinical features, management, and outcomes of expulsive choroidal hemorrhage during cataract surgery: 13-year experience of a tertiary eye center.

PURPOSE: To study the risk factors, clinical features, management, and outcomes of intraoperative expulsive choroidal hemorrhage (ECH) during cataract surgery. SETTING: Aravind Eye Hospital, Madurai, Tamil Nadu, India. DESIGN: Retrospective hospital-based study. METHODS: Of the 1 167 250 patients who underwent cataract surgery between 2008 and 2020, patients diagnosed with intraoperative ECH were included. Demography, ocular and systemic risk factors, visual acuity, type of ocular anesthesia, intraoperative and postoperative records, management, and surgical outcomes were analyzed. RESULTS: 52 eyes (0.004%) of 1 167 250 patients had ECH. Of the 52 cases, 43 cases (incidence rate 0.006%) were reported in the years 2008 to 2015 and 9 cases (incidence rate 0.002%) in the years 2016 to 2020. The change in the ocular anesthesia from peribulbar and retrobulbar anesthesia (2008 to 2015) to sub-Tenon anesthesia (2016 to 2020) was associated with a reduced rate of ECH ( P = .002). 28 eyes (53.8%) experienced limited ECH and 24 eyes (46.2%) full-blown ECH. The visual outcome was better in eyes with limited ECH compared with full-blown suprachoroidal hemorrhage in all follow-up visits. The median vision (interquartile range) before the cataract surgery and at postoperative day 1 were 1.30 (0.78 to 2.60) and 2.45 (1 to 2.75), respectively. The median final vision (interquartile range) after the secondary surgical intervention was 2.2 (0.60 to 2.60). CONCLUSIONS: This series included 52 eyes with ECH, recognized associations of ECH with different types of anesthesia and with different cataract surgical procedures, and described management of ECH. Postoperative visual outcome was poor.

Digitally assisted vitreoretinal surgery: A unique surgical teaching tool for beginners.

PURPOSE: To study the role of digitally assisted vitreoretinal surgery (DAVS) as a learning and teaching tool compared to that of the standard binocular side-scope of the conventional analog microscope (CAM). METHODS: This was a cross-sectional, observational study conducted at a tertiary eye care center and teaching institute in South India. Postgraduate residents and clinical fellows observed a predecided set of retinal surgical procedures using both DAVS and CAM. A detailed questionnaire was used to compare the participants' subjective scoring of both the platforms in terms of level of comfort, clarity of image and stereopsis, level of understanding, and overall impression. RESULTS: Thirty-six participants, including 20 residents and 16 fellows, took part in this study. DAVS obtained a higher score for all 15 questions compared to CAM and the differences were statistically significant. DAVS obtained a mean score of 4.80 (median: 5) whereas CAM obtained a mean score of 3.14 (median: 3) on a grading scale of 1-5 with regard to the overall experience of surgical viewing through either platform (P < 0.01). CONCLUSION: DAVS is a better learning and teaching tool compared to the side scope of the CAM from a learner's perspective. Thus, DAVS can help beginners in the field of vitreoretinal surgery obtain a better understanding of the surgical steps prior to the initiation of hands-on training.

Challenges in Post-cataract Surgery Nocardia Endophthalmitis: Management Strategies and Clinical Outcomes.

PURPOSE: To describe the clinical and microbiological features, management strategies, outcomes, and challenges in post-cataract surgery nocardia endophthalmitis. METHODS: We evaluated 28 eyes with culture-confirmed Nocardia endophthalmitis following cataract surgery. Data were collected regarding age, gender, clinical presentation, management modalities used, and final outcomes. RESULTS: Mean age of the patients was 66.07 + -8.6 years. Four eyes (14.3%) underwent early pars plana core vitrectomy, while 18 eyes (64.3%) underwent tap/inject regimen followed by observation for 48 h, with or without a delayed vitrectomy. Thirteen eyes (46.4%) received amikacin treatment. Visual acuity (VA) improved from presentation in 9/28 (32.1%) eyes, worsened in 14/28 (50%) eyes, and showed no change in 5/28 eyes (17.9%). CONCLUSIONS: We did not find any significant association between functional outcome and time of surgery or presenting VA. Additional amikacin may be considered if there is a strong suspicion of nocardia endophthalmitis, as it may help in achieving better anatomical outcomes.

Retinal manifestations in patients with SARS-CoV-2 infection and pathogenetic implications: a systematic review.

INTRODUCTION: The pandemic of COVID-19 has been caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. Apart from respiratory malfunction, COVID-19 causes a system-wide thromboembolic state, leading to serious cardiovascular, cerebrovascular and peripheral vascular manifestations. However, our knowledge regarding retinal manifestations due to systemic COVID-19 is minimal. This systematic review has comprehensively summarized all retinal manifestations secondary to COVID-19 disease recorded till date since the beginning of the pandemic. METHODS: All studies published till November 27, 2020, which have reported retinal manifestations in COVID-19 patients were systematically reviewed using the PRISMA statement. RESULTS: We included 15 articles: 11 case reports and four cross-sectional case series. The most commonly reported manifestations which did not affect visual acuity were retinal hemorrhages and cotton wool spots. The most common vision threatening manifestation was retinal vein occlusion with associated macular edema. Rarely, patients may also present with retinal arterial occlusions and ocular inflammation. These manifestations may occur from as soon as within a week after the onset of COVID-19 symptoms to more than 6 weeks after. CONCLUSION: Mostly causing milder disease, COVID-19 may however lead to severe life-threatening thromboembolic complications, and systemic antithrombotic therapy has been suggested as a prophylactic and therapeutic management strategy for patients affected with serious systemic disease. However, both sick and apparently healthy patients may suffer from various retinal complications which may lead to loss of vision as well. No consensus regarding management of retinal complications with anticoagulants or anti-inflammatory medications have been proposed; however, they may be tackled on individual basis.

Ochrobactrum anthropi: A Rare Cause of Culture-Proven Acute Post-Operative Cluster Endophthalmitis.

AIM: To report the clinical presentation and management outcomes of an outbreak of culture-proven post-operative endophthalmitis (POE) secondary to Ochrobactrum anthropi. METHODS: This study was conducted at a tertiary-care eye hospital in South India. RESULTS: Fifty-five patients underwent cataract surgery by six surgeons on three consecutive days in the same surgical facility in September 2020. Four patients developed POE after a mean interval of 12.0 ± 4.8 days and underwent immediate vitreous tap and intravitreal antibiotic injections (Vancomycin and Ceftazidime). All patients required a core vitrectomy (culture positive, n = 4/4). Two patients underwent an additional intraocular lens explantation, 2 and 4 months after presentation. All the four patients showed good anatomical and functional recoveries (mean follow-up, 5.75 ± 1.5 months). Two other patients had an exaggerated post-operative inflammation, which was successfully treated with topical medications. CONCLUSIONS: O. anthropi is a rare cause of acute POE. Although the isolated organism was multi-drug resistant, the outcome was good in all the patients.

Anatomical and functional features of photic retinopathy: a spectral domain optical coherence tomography-based longitudinal study.

BACKGROUND: Photic retinopathy may lead to permanent foveal structural injury, leading to irreversible visual acuity loss. METHOD: This prospective observational study evaluated 51 eyes of 30 patients with photic retinopathy. Optical coherence tomography (OCT) imaging was performed for all the eyes at baseline and final follow-up. All the eyes showed a focal outer retinal defect on spectral-domain OCT (SD-OCT) at the junction of the inner and outer photoreceptor segments. SD-OCT was used to measure central macular thickness, maximum horizontal dimension of the defect, maximum defect thickness, and the photic retinopathy index (PRI) through the foveal raster scan. RESULTS: Although PRI improved significantly at the final follow-up from baseline with a 17% improvement in PRI after a period of 6 months in photic retinopathy eyes, visual acuity declined for 14% of the patients and was stable for 84%. There was mild correlation of visual acuity with baseline PRI. Baseline PRI was significantly higher in eyes with poorer presenting visual acuity (VA). In total, 33.3% of the eyes showed partial ellipsoid zone recovery at 6 months. The area under curve of the receiver operator characteristic curve for partial ellipsoid zone recovery with the mean baseline PRI as the independent variable was poor at 0.612. CONCLUSION: OCT-based ultrastructural features in photic retinopathy seem to have poor correlation with presenting or final visual acuity. To the best of our knowledge, this is the largest study on longitudinal OCT evaluation of photic retinopathy eyes in literature.

Evaluation of retinal functional changes after macular hole surgery using heavy brilliant blue G dye for internal limiting membrane staining: A prospective, single blind, randomized controlled trial.

PURPOSE: To evaluate retinal functional changes after idiopathic macular hole (MH) surgery using heavy brilliant blue G (hBBG) dye for internal limiting membrane (ILM) staining. METHODS: Forty-four eyes with idiopathic MH were randomized into two groups - 24 eyes undergoing vitrectomy with ILM peeling using hBBG staining and 20 eyes without staining; anatomical and functional status (with microperimetry (MP)) at baseline and during postoperative follow-up were noted and compared. RESULTS: All eyes had closure of MH postoperatively and overall baseline MP indices (average threshold, AT; foveal sensitivity, FS) improved significantly at 6 weeks and 6 months of follow-up. AT and FS showed significant improvement at 6 weeks and 6 months from baseline in both individual groups (P < 0.001). Intergroup comparison showed that there was no statistically significant difference in AT and FS values at any point of time (baseline, 6 weeks, 6 months) between staining and no-stain group. No eyes in our cohort had any unexplained visual loss. CONCLUSION: Functional parameters of macula improved significantly after successful MH surgery using hBBG for staining the ILM.