Evaluating Truenat Assay for the Diagnosis of Ocular Tuberculosis and Detection of Drug Resistance.

BACKGROUND: Truenat MTB Plus assay was evaluated for diagnosing ocular tuberculosis (OTB) and detecting multi-drug resistant (MDR) and extremely-drug resistant (XDR) OTB. METHODS: A total of 75 vitreous fluid specimens [five confirmed OTB, 40 clinically suspected OTB and 30 controls] were subjected to Truenat MTB Plus, multiplex PCR, and Xpert Ultra. Chips of Truenat were used for detecting rifampicin, isoniazid, fluoroquinolone and bedaquiline resistance. The performance was compared against culture, composite reference standard, and gene sequencing. RESULTS: The overall sensitivity of TruePlus, MPCR, and Ultra in diagnosing OTB was 66.6%, 73.3%, and 55.5%, respectively. Out of six cases with mutations in rpoB gene, RifR was detected in five by TrueRif and four by Ultra. Three MDR and one XDR-OTB were reported by Truenat. CONCLUSION: Truenat assay along with its strategic chips is a rapid and reliable tool for diagnosis of OTB and detection of drug resistance, including MDR and XDR-OTB.Abbreviations: OTB: Ocular tuberculosis; XDR: Extremely drug resistant; Ultra: Xpert MTB/RIF Ultra; Xpert: Xpert MTB/RIF; PCR: polymerase chain reaction; NAATs: Nucleic acid amplification tests; MDR: Multi Drug Resistant; NSP: National Strategic plan for elimination of tuberculosis; FqR: Fluoroquinolone resistant; BdqR: bedaquiline resistant; TrueRif: Truenat MTB Rif Dx; TruePlus: Truenat Plus; INH: Isoniazid; DST: Drug susceptibility testing; MGIT: Mycobacterial growth indicator tube; CRF: Composite reference standard; PPV: positive predictive value; NPV: negative predictive value; EPTB: extrapulmonary tuberculosis; VF: vitreous fluid; DNA: deoxyribonucleic acid; ATT: antitubercular therapy; RifR: Rifampicin resistance; RifS: Rifampicin susceptible; RifI: Rifampicin indeterminate.

Pathogenesis of Bacterial Uveitis.

PURPOSE: To describe the pathogenesis and the general immune mechanisms of the most frequent causes of bacterial uveitis. METHODOLOGY: Narrative review. RESULTS: Both extra- and intracellular bacteria can induce uveitis, whereas intracellular bacteria are generally transported into the inner eye via cells of the innate immune system, mainly macrophages. Systemic adaptive immunity is usually induced before the bacteria are localized to the inner eye, and once T and B cells have detected the pathogens behind the blood-eye barriers they elicit an acute and/or chronic inflammatory response deteriorating visual acuity that can severely affect the non-regenerating, intraocular tissues. CONCLUSIONS: An understanding of pathogenic mechanisms, and its correlation with clinical and imaging features, can facilitate early recognition of microbial factors and institution of appropriate therapy.

Tacrolimus Induced Thrombotic Microangiopathy (TMA) Presenting as Acute Macular Neuroretinopathy.

This report highlights the association of tacrolimus use with acute macular neuroretinopathy (AMN). A 27-year-old woman, a known case of diffuse proliferative membranous glomerulonephritis, developed abnormal body movements, loss of consciousness, and blurring of vision in the left eye, after 3 months of starting tacrolimus. Blood investigations revealed anemia, thrombocytopenia, raised urea and creatinine levels, and raised LDH levels. A diagnosis of tacrolimus induced hemolytic uremic syndrome (HUS) with posterior reversible encephalopathy syndrome (PRES) was made. Ocular examination revealed a reddish-brown petaloid retinal lesion, which was better appreciated on red-free imaging as dark grey area pointing towards the fovea. OCT-A and SD-OCT revealed flow voids in deep retinal plexus, and disruption of ellipsoid and interdigitation zone, respectively, findings consistent with AMN. To the best of our knowledge, it is the first report of association of tacrolimus with AMN.

Comparative Evaluation of GeneXpert MTB/RIF Ultra and GeneXpert MTB/RIF for Detecting Tuberculosis and Identifying Rifampicin Resistance in Pars Plana Vitrectomy Samples of Patients with Ocular Tuberculosis.

BACKGROUND: Xpert MTB/RIF Ultra (Ultra) was evaluated for the first time on Ocular tuberculosis (OTB) samples and compared with Xpert. METHODS: Seventy five vitreous fluid samples (3 confirmed OTB, 47 clinically suspected OTB, and 25 controls) were subjected to Ultra, Xpert and Multiplex-PCR and compared against culture, composite reference standard (CRS), and gene sequencing. RESULTS: The sensitivity of Ultra was 50% in diagnosing OTB (100% against culture and 46.8% against CRS). The overall sensitivity of Xpert and MPCR was 16% and 72%, respectively. Xpert missed three culture-positive cases and MPCR detected additional 11. Ultra and Xpert missed two and four cases of RifR, respectively. A total of 13(59%) cases were reported 'trace' by Ultra in which RifR could not be evaluated. CONCLUSION: Ultra outperformed Xpert in diagnosing OTB. The advantage of Ultra's simultaneous RifR detection is lost since the trace bacterial loads in the specimens cause indeterminate results of RifR testing.Abbreviations: OTB: Ocular tuberculosis; Ultra: Xpert MTB/RIF Ultra; Xpert: Xpert MTB/RIF, MPCR: multiplex polymerase chain reaction; NAATs: Nucleic acid amplification tests; MLAMP: multitargeted loop-mediated isothermal amplification; PPV: positive predictive value; NPV: negative predictive value; EPTB: extrapulmonary tuberculosis; VF: vitreous fluid; DNA: deoxyribonucleic acid; ATT: antitubercular therapy; RifR: Rifampicin resistance; RifS: Rifampicin susceptible; RifI: Rifampicin indeterminate.

A hybrid 26G needle drainage technique in scleral buckling: A mini scleral cut-down.

Purpose: To evaluate the efficacy and safety of hybrid 26-gauge needle drainage in scleral buckling for rhegmatogenous retinal detachment (RRD). Methods: In this retrospective study, we included patients who underwent scleral buckling surgery along with subretinal fluid (SRF) drainage using the 'Hybrid 26G needle drainage technique'. Pre-operative assessment included the best corrected visual acuity (BCVA), lens status, and extent of retinal detachment. Intra-operative surgical details such as the height of retinal detachment, number of attempts required to drain the fluid, amount of fluid drained, adequacy of break buckle relationship, and any intra-operative or post-operative complications were noted. Post-operatively, the final visual outcome and retina status were assessed at 3 months of follow-up. Results: A total of 10 eyes with primary RRD and proliferative vitreoretinopathy C1 or less were included. Pre-operatively, the mean BCVA was 2.43 ± 1.01 logMAR units, which improved significantly to 0.679 ± 0.45 logMAR units (p value < 0.05) at 3 months of follow-up. Regarding the extent of RRD, five eyes (50%) had a total detachment, two eyes (20%) had a sub-total detachment, and three eyes (30%) had an inferior detachment. Four eyes had shallow detachment, four had a moderate detachment, and two eyes had bullous detachment. Complete drainage of SRF (>75%) was achieved in five patients, and a partial but adequate drainage (50-75%) was achieved in the rest of the five patients. In none of the patients, inadequate or dry tap was encountered. No intra-operative complications were encountered. The retina was attached in eight out of ten eyes at 1 week and at a 1-month follow-up period. Two patients required pars plana vitrectomy for persistent SRF. The retina was attached in all the patients at 3 months of follow-up. Conclusion: The 'Hybrid needle drainage' technique is a safe and effective technique for SRF drainage in scleral buckling surgery.

Sympathetic ophthalmia: A comprehensive update.

Sympathetic ophthalmia is a rare, bilateral, granulomatous, panuveitis following penetrating trauma or surgery to one eye. Clinical presentation commonly occurs within the first year of trauma occurrence but can be delayed by several years. It manifests as acute/chronic granulomatous uveitis with yellowish-white choroidal lesions or Dalen-Fuchs nodules. Initially, patients respond rapidly to corticosteroid therapy, but a majority require long-term use of corticosteroid-sparing agents to prevent recurrences. The purpose of this review is to elaborate on the current understanding of the pathophysiology, the importance of multimodal imaging in early diagnosis, and the role of newer immunomodulatory and biological agents in recalcitrant cases.

Intraoperative haemorrhagic choroidal detachment during MicroIncision Vitrectomy Surgery (MIVS): a unique mechanism.

Haemorrhagic choroidal detachment (HCD) is a dreaded intraoperative complication of ophthalmic surgery, despite being rare. Multiple systemic and ocular risk factors of HCD have been reported. Acute hypotony during surgery is considered one of the most important precipitating factors. We herein describe a series of events during pars plana vitrectomy surgery for management of rhegmatogeneous retinal detachment which lead to localised HCD. We believe that the pathogenesis of localised HCD is related to compressive decompressive forces during the final tie of the encircling element after fluid air exchange.

Smartphone Disc Photography Versus Standard Stereoscopic Disc Photography as a Teaching Tool.

Optic disc photographic assessment was performed using an unmodified iPhone Xs Max. A video recording of the disc and peripapillary area was obtained in 5 patients. Good quality screenshots were acquired from the video, and, from them, a single best quality image was selected. This was compared with their respective standard optic disc stereo photograph. A glaucomatologist blinded to the type of image acquisition studied these images and concluded that both images could help well in the identification of glaucomatous optic disc features; however, the stereo photograph had better clarity than the iPhone static image. Nevertheless, the iPhone offered the advantage of real-time video assessment of the disc and peripapillary area and could serve as a practical and handy tool for telemedicine and teaching purposes.