Insights into the genomic features and lifestyle of B1 subcluster mycobacteriophages.

Bacteriophages infecting Mycobacterium smegmatis mc2155 are numerous and, hence, are classified into clusters based on nucleotide sequence similarity. Analyzing phages belonging to clusters/subclusters can help gain deeper insights into their biological features and potential therapeutic applications. In this study, for genomic characterization of B1 subcluster mycobacteriophages, a framework of online tools was developed, which enabled functional annotation of about 55% of the previously deemed hypothetical proteins in B1 phages. We also studied the phenotype, lysogeny status, and antimycobacterial activity of 10 B1 phages against biofilm and an antibiotic-resistant M. smegmatis strain (4XR1). All 10 phages belonged to the Siphoviridae family, appeared temperate based on their spontaneous release from the putative lysogens and showed antibiofilm activity. The highest inhibitory and disruptive effects on biofilm were 64% and 46%, respectively. This systematic characterization using a combination of genomic and experimental tools is a promising approach to furthering our understanding of viral dark matter.

COVID associated mucormycosis: A preliminary study from a dedicated COVID Hospital in Delhi.

BACKGROUND: It is an incontrovertible fact that the Rhino Orbital Cerebral Mucormycosis (ROCM) upsurge is being seen in the context of COVID-19 in India. Briefly presented is evidence that in patients with uncontrolled diabetes, a dysfunctional immune system due to SARS-COV-2 and injudicious use of corticosteroids may be largely responsible for this malady. OBJECTIVE: To find the possible impact of COVID 19 infection and various co-morbidities on occurrence of ROCM and demonstrate the outcome based on medical and surgical interventions. METHODOLOGY: Prospective longitudinal study included patients diagnosed with acute invasive fungal rhinosinusitis after a recent COVID-19 infection. Diagnostic nasal endoscopy (DNE) was performed on each patient and swabs were taken and sent for fungal KOH staining and microscopy. Medical management included Injection Liposomal Amphotericin B, Posaconazole and Voriconazole. Surgical treatment was restricted to patients with RT PCR negative results for COVID-19. Endoscopic, open, and combined approaches were utilized to eradicate infection. Follow-up for survived patients was maintained regularly for the first postoperative month. RESULTS: Out of total 131 patients, 111 patients had prior history of SARS COVID 19 infection, confirmed with a positive RT-PCR report and the rest 20 patients had no such history. Steroids were received as a part of treatment in 67 patients infected with COVID 19. Among 131 patients, 124 recovered, 1 worsened and 6 died. Out of 101 known diabetics, 98 recovered and 3 had fatal outcomes. 7 patients with previous history of COVID infection did not have any evidence of Diabetes mellitus, steroid intake or any other comorbidity. CONCLUSION: It can be concluded that ROCM upsurge seen in the context of COVID-19 in India was mainly seen in patients with uncontrolled diabetes, a dysfunctional immune system due to SARS-COV-2 infection and injudicious use of corticosteroids.

Analysis of Corneal Scheimpflug Densitometry and Ocular Wavefront Aberrations Post Descemet Stripping Automated Endothelial Keratoplasty.

PURPOSE: To assess the role of corneal densitometry and wavefront aberrations post Descemet stripping automated endothelial keratoplasty (DSAEK) and their correlation with visual acuity. METHODS: Twenty-seven eyes of 25 patients with nonresolving corneal edema for more than 3 months as a result of Fuchs endothelial corneal dystrophy, pseudophakic bullous keratopathy, or secondary endothelial dysfunction were enrolled in a prospective interventional study and underwent DSAEK. Postoperative evaluation for corneal aberrations, including Higher order aberrations (HOAs) and corneal densitometry (CD), was performed using anterior-segment optical coherence tomography (Avanti RTvue XR; Optovue) and Scheimpflug imaging (Pentacam, Oculus Optikgeräte GmbH, Wetzlar, Germany) at 6 months. A correlation analysis of corneal aberrations, including HOAs and CD, with postoperative best-corrected visual acuity at 6 months was performed. RESULTS: Mean best-corrected visual acuity (BCVA) improved from 1.67±0.53 log of minimum angle of resolution (logMAR) to 0.2±0.22 logMAR post DSAEK at 6 months (P≤0.0001). At 6 months, mean root-mean-square (RMS) total corneal aberrations (includes HOA and low-order aberration [LOA]), RMS total HOA, and RMS LOA of the central 6-mm zone were 4.99±2.64, 1.80±0.9, and 4.55±2.64, respectively. The mean corneal densitometry from anterior, central, and posterior zones were 39.12±12.77, 23.9±7.2, and 13.54±2.04 gray scale units, respectively. Total anterior aberrations (r=0.051; P=0.006), anterior LOA (r=0.049; P=0.009), total corneal aberrations (r=0.051; P=0.001), total HOAs (r=0.095; P=0.057) and LOAs (r=0.050; P=0.002), and total CD from 0 to 2 mm (r=0.010; P=0.038) and 2 to 6 mm (r=0.014; P=0.018) showed a significant inverse correlation with postoperative BCVA. CONCLUSION: There was an inverse relationship between post DSAEK BCVA and total corneal HOAs and full-thickness densitometry at 6 months. Scheimpflug imaging with added tools for corneal aberration and densitometry analysis gives further insight into the suboptimal vision achieved despite transparent corneas post DSAEK.

Clinico-Radiological-Pathological Correlation of Visual Loss in COVID-Associated Rhino-Orbito-Cerebral Mucormycosis.

PURPOSE: To correlate the clinical, radiological, and histopathological features in Covid-associated Rhino-orbito-cerebral mucormycosis cases presenting with acute visual loss. DESIGN: Cross-sectional study. METHODS: Covid-associated Rhino-orbito-cerebral mucormycosis cases with unilateral visual loss, planned for exenteration, underwent orbital and ophthalmological ocular examination. The available radiological sequences, doppler ultrasonography and histopathology findings were correlated with clinical manifestations. RESULTS: The median age was 51 years and the male: female ratio was 3:1. All except one presented with unilateral ophthalmoplegia. The ocular media were hazy in 2 eyes. In 8 eyes, retinal changes were suggestive of occlusion of CRA (6), combined occlusion of CRA and central retinal vein (1), and myopic degeneration with hypertensive retinopathy (1). The contralateral eye showed retinal ischemic changes in one patient. Radiological imaging showed orbital apex involvement in the 10 affected eyes and one contralateral eye. Ipsilateral cavernous sinus thrombosis, diffusion restriction on MRI of optic nerve, internal carotid artery narrowing/thrombosis, and cortical watershed infarcts were seen in 8, 4, 4, and 2 cases, respectively. The blood flow in CRA and ophthalmic artery was absent or reduced in all the 10 affected eyes and in 1 contralateral eye. On histopathology, orbital fat necrosis, fungal hyphae, acute inflammation, granuloma formation, ischemic thrombosis of ophthalmic artery was observed in 10 specimens. CRA was patent in 9 and thrombosed in 1 eye. Optic nerve was ischemic in 8 and viable in 2 eyes. CONCLUSION: Acute visual loss in ROCM cases is associated with orbital apex involvement and thrombotic ischemia of ophthalmic artery. Cessation of flow in CRA possibly occurs secondary to ophthalmic artery thrombosis.

Evaluation of SARS-CoV-2 in Tears of Patients with Moderate to Severe COVID-19.

PURPOSE: To investigate the presence of SARS-CoV-2 RNA in tears of patients with moderate to severe coronavirus disease 2019 (COVID-19). DESIGN: Cross-sectional study. PARTICIPANTS: Patients with laboratory-proven moderate to severe COVID-19. METHODS: Tears were collected within 48 hours of laboratory confirmation using 3 methods: conjunctival swab plus Schirmer's test strips (group 1), conjunctival swab (group 2), and Schirmer's test strips (group 3). Samples from both the eyes of each patient were transported in a single viral transport media for real-time RT-PCR. Detailed demographic profiles, systemic symptoms, comorbidities, and ocular manifestations were noted. MAIN OUTCOME MEASURES: Viral load of a sample was determined using cycle threshold (Ct) value of E gene. A specimen was considered to show positive results if the amplification curve for the E gene crossed the threshold line within 35 cycles and if it showed positive results on an RNA-dependent RNA polymerase or open reading frame 1b gene assay. RESULTS: Of the 78 patients enrolled in the study, samples from 3 patients were found to be inadequate for analysis. Thirty-six patients (48%) had moderate disease, whereas 39 patients (52%) had severe disease, with no ocular involvement in any patient. In the 75 patients, RT-PCR analysis of tears showed positive results in 18 patients (24%), and 29 of 225 samples (12.9%) showed positive results. Positive results were found in 11 (14.7%), 11 (14.7%), and 7 (9.3%) patients in groups 1, 2, and 3, respectively (P = 0.3105). Mean Ct values in groups 1, 2, and 3 were 28.36 ± 6.15, 29.00 ± 5.58, and 27.86 ± 6.46 (P = 0.92), respectively. Five patients showed positive RT-PCR results by all 3 methods (mean Ct value, 25.24 ± 6.33), and 12 patients showed positive results by any of the 3 methods (mean Ct value, 32.16 ± 1.94), the difference in Ct values being statistically significant (P = 0.029). The median value of symptomatology in patients with positive RT-PCR results from tears was 5 days (range, 4-9 days). CONCLUSIONS: SARS-CoV-2 RNA was detected in tears of 24% of patients with laboratory-proven moderate to severe COVID-19. Conjunctival swab remains the gold standard of tear collection for RT-PCR assay. A significantly higher possibility of viral transmission exists through tears in patients with moderate to severe COVID-19.

Design and Synthesis of Various 5'-Deoxy-5'-(4-Substituted-1,2,3-Triazol-1-yl)-Uridine Analogues as Inhibitors of Mycobacterium tuberculosis Mur Ligases.

The synthesis of hitherto unknown 5'-deoxy-5'-(4-substituted-1,2,3-triazol-1-yl)-uridine and its evaluation, through an one-pot screening assay, against MurA-F enzymes involved in Mycobacterium tuberculosis (Mtb), are described. Starting from UDP-N-acetylmuramic acid (UDP-MurNAc), the natural substrate involved in the peptidoglycan biosynthesis, our strategy was to substitute the diphosphate group of UDP-MurNAc by a 1,2,3-triazolo spacer under copper-catalyzed azide-alkyne cycloaddition conditions. The structure-activity relationship was discussed and among the 23 novel compounds developed, N-acetylglucosamine analogues 11c and 11e emerged as the best inhibitors against the Mtb MurA-F enzymes reconstruction pathway with an inhibitory effect of 56% and 50%, respectively, at 100 µM. Both compounds are selective inhibitors of Mtb MurE, the molecular docking and molecular dynamic simulation suggesting that 11c and 11e are occupying the active site of Mtb MurE ligase.

Crescentic Tuck in Lamellar Keratoplasty-A Novel Technique in a Case of Advanced Pellucid Marginal Corneal Degeneration.

PURPOSE: To describe a new surgical technique "crescentic tuck in lamellar keratoplasty" for the management of advanced pellucid marginal corneal degeneration (PMCD). METHODS: A 45-year-old man with advanced PMCD and maximal thinning in the inferior juxtalimbal periphery underwent a crescentic lamellar keratoplasty in the right eye. Best-corrected visual acuity was 6/60 with no further improvement because of severe irregular astigmatism. Thinnest pachymetry in the peripheral cornea was 280 µm. Peripheral crescent-shaped lamellar corneal dissection of 3.5-mm width was performed, and an intrastromal pocket was fashioned from 4 to 8 O'clock, extending beyond limbus. A crescent-shaped donor corneal button of 3.5-mm width was denuded of its endothelium and beveled in inferior periphery to create a flange. The flange was tucked into the peripheral scleral pocket. The donor graft was secured to the host bed using 10-0 nylon interrupted sutures. RESULTS: Donor cornea integrated with the host bed over time and best spectacle-corrected visual acuity at 1 year improved to 6/9 with -1.25/-3.5 D × 90°. The simK (simulated keratometry) changed from 41.6/56.3 diopters (D) to 45.1/50.6 D. The astigmatism reduced from 14.6 D to 5.5 D. CONCLUSION: Crescentic tuck in lamellar keratoplasty provides good apposition of the donor lenticule and tectonic support to the peripheral thin cornea while preserving the peripheral limbal stem cells. Additionally, there is a significant reduction in the astigmatism, resulting in visual improvement.

Alterations in contact lens fitting parameters following cross-linking in keratoconus patients of Indian ethnicity.

BACKGROUND: Most studies have either excluded patients using contact lens or not taken their effect while analyzing post-collagen cross-linkage (CXL) changes. This study aims to study impact of CXL on lens fit in both quantitative and qualitative manner. OBJECTIVE: To evaluate changes in CL fit post-CXL and to correlate these changes with alterations in corneal topographic parameters. STUDY DESIGN: Prospective intervention study on 20 keratoconic eyes of 14 patients (age > 18 years), with mean follow-up of 6 months. METHODS: Preoperative evaluation included UCVA, BCVA, corneal topography, AS-OCT and contact lens fit. Patients were evaluated at 2 weeks, 1, 3, 4 and 6 months post-CXL; contact lens trial with standard rigid gas permeable (RGP) lens performed at 3 and 6 months. MAIN OUTCOME MEASURE: Changes in objective and subjective parameters of lens fit. RESULTS: Over 6-month follow-up post-CXL, improvement in visual acuity by one Snellen line, both UCVA and BCVA, and decrease in flat/mean/apical K by 0.8 D, 0.8 D and 1.3 D, respectively, resulted in significant improvement in RGPCL fit. Almost 20% increase in near-ideal fit, 100% acceptable fit, 65% improved subjective comfort with 8 h/day increase in duration of comfortable CL wear were observed. CONCLUSION: Despite no statistically significant change in objective parameters of lens fit, a tendency for flatter lens fit along with contact lens induced further flattening of the ectatic cornea which resulted in marked improvement in both objective and subjective contact lens fit.

Synthesis, pharmacological evaluation and molecular docking of pyranopyrazole-linked 1,4-dihydropyridines as potent positive inotropes.

1,4-Dihydropyridines are well-known calcium channel blockers, but variations in the substituents attached to the ring have resulted in their role reversal making them calcium channel activators in some cases. We describe the microwave-assisted eco-friendly approach for the synthesis of pyranopyrazole-1,4-dihydropyridines, a new class of 1,4-DHPs, under solvent-free conditions in good yield, and screen them for various in silico, in vitro and in vivo activities. The in vivo experimentation results show that the compounds possess positive inotropic effect, and the docking results validate their good binding with calcium channels. Compounds 7c, 7g and 7i appear to be the most effective positive inotropes, even at low doses, and bind with the calcium channels even more strongly than Bay K 8644, a well-known calcium channel activator. The chronotropic effect for the new compounds was also studied. The target and off-target affinity profiling supported the in vivo results and revealed that the hybridized pyranopyrazole dihydropyridine scaffold has delivered new moderate hits, to be optimized, for the cytochrome P450 3A4 enzymes, opening avenues for combined pharmacological activity through standard structural modification.

Emerging OP354-Like P[8] Rotaviruses Have Rapidly Dispersed from Asia to Other Continents.

The majority of human group A rotaviruses possess the P[8] VP4 genotype. Recently, a genetically distinct subtype of the P[8] genotype, also known as OP354-like P[8] or lineage P[8]-4, emerged in several countries. However, it is unclear for how long the OP354-like P[8] gene has been circulating in humans and how it has spread. In a global collaborative effort 98 (near-)complete OP354-like P[8] VP4 sequences were obtained and used for phylogeographic analysis to determine the viral migration patterns. During the sampling period, 1988-2012, we found that South and East Asia acted as a source from which strains with the OP354-like P[8] gene were seeded to Africa, Europe, and North America. The time to the most recent common ancestor (TMRCA) of all OP354-like P[8] genes was estimated at 1987. However, most OP354-like P[8] strains were found in three main clusters with TMRCAs estimated between 1996 and 2001. The VP7 gene segment of OP354-like P[8] strains showed evidence of frequent reassortment, even in localized epidemics, suggesting that OP354-like P[8] genes behave in a similar manner on the evolutionary level as other P[8] subtypes. The results of this study suggest that OP354-like P[8] strains have been able to disperse globally in a relatively short time period. This, in combination with a relatively large genetic distance to other P[8] subtypes, might result in a lower vaccine effectiveness, underscoring the need for a continued surveillance of OP354-like P[8] strains, especially in countries where rotavirus vaccination programs are in place.

Evaluation of pattern electroretinogram in retinal vein occlusion treated with intravitreal triamcinolone acetonide.

PURPOSE: To evaluate pattern electroretinogram (pattern ERG) and anatomical changes in optical coherence tomography (OCT) in acute retinal vein occlusion with macular oedema after intravitreal triamcinolone acetonide (IVTA) injection. METHODS: In this prospective interventional study, 20 patients with acute retinal vein occlusion (branch and central) of less than 1 month duration were evaluated for pattern ERG, best-corrected visual acuity (BCVA), central macular thickness on OCT, and contrast sensitivity (CS) before and 1, 6 and 12 weeks after 1 mg IVTA injection. RESULTS: The amplitude of P50 wave (pattern ERG) improved from 3.01 ± 1.22 to 3.56 ± 1.29 µv, mean logMAR BCVA improved from 1.10 ± 0.60 to 0.69 ± 0.45, and CS improved from 0.45 ± 0.41 to 0.79 ± 0.29; mean central macular thickness (CMT) decreased from 515.35 ± 202.83 to 358.35 ± 135.4µ at 12 weeks. All the values were statistically significant (p value < 0.001). CONCLUSION: IVTA injection in acute retinal vein occlusion with macular oedema results in electrophysiological (pattern ERG) improvement in addition to anatomical (OCT) improvement.

Pattern ERG in central serous retinopathy.

BACKGROUND: To evaluate the pattern electroretinogram (PERG) in central serous retinopathy. METHODS: In this prospective study, 20 patients with recent onset (<6 weeks) unilateral CSR were studied with the fellow eye acting as control. BCVA, psychophysical parameters, FFA, OCT, flash and pattern ERG were evaluated. RESULTS: The mean P50 amplitude in the affected eye at presentation was 2.36 ± 0.8 µv compared to 3.24 ± 0.85 µv in the normal eye. At 12 weeks, the mean P50 amplitude in the affected eye was 3.16 ± 0.88 µv compared to 3.63 ± 0.82 µv in the normal eye. The reduction of 27 % in P50 amplitude even after recovery was statistically significant (P < 0.001). A reduction of 19.77 % in the amplitude of N95 wave in the affected eye compared to the normal eye was seen, which was statistically significant (P < 0.001). In the affected eye, there was statistically significant improvement in the psychophysical tests at 12 weeks. CONCLUSIONS: This study reveals that P50 component of the PERG is reduced in cases of CSR, indicating functional disturbance of the macular photoreceptors. A normal flash ERG indicates that pathology is electrophysiologically localised to macula without affecting general retina. Residual deficit in the PERG explains poor quality of vision in spite of normal anatomical apposition and quantitative 6/6 visual acuity.

Comparative evaluation of higher-order aberrations and corneal asphericity between wavefront-guided and aspheric LASIK for myopia.

PURPOSE: To compare visual outcome, higher-order aberrations, and corneal asphericity (Q value) between wavefront-guided and aspheric LASIK for myopia and myopic astigmatism. METHODS: Forty patients were randomly selected to receive wavefront-guided LASIK (wavefront-guided group) or aspheric LASIK (aspheric group) (40 eyes of 20 patients in each group) using the Technolas 217z excimer laser platform (Bausch & Lomb, Rochester, NY). Flaps were created using the Zyoptix XP microkeratome (Bausch & Lomb). Preoperative and postoperative evaluation included uncorrected distance visual acuity (UDVA), corneal topography, wavefront aberrometry, and contrast sensitivity. Minimum follow-up period was 6 months. RESULTS: At 6 months postoperatively, the aspheric group had significantly better UDVA (logMAR 0.04 ± 0.04 [Snellen 20/16] [range: -0.079 to 0.000]) and lower mean residual spherical error (+0.10 ± 0.52 diopters [D] [range: -1.12 to 1.25 D]) than the wavefront-guided group (logMAR UDVA 0.00 ± 0.07 [range: -0.079 to 0.176]; MRSE -0.35 ± 0.47 D [range: -1.5 to 0.62 D]) (P = .003 and < .001, respectively). Mean change in higher-order aberration root mean square at 6 months postoperatively (6-mm pupil) was 0.16 ± 0.17 µm after aspheric LASIK and 0.27 ± 0.28 µm after wavefront-guided LASIK (P = .02). Aspheric LASIK induced minimal change in spherical aberrations postoperatively (0.03 ± 0.12 µm, P = .09), unlike wavefront-guided LASIK (0.23 ± 0.17 µm, P < .01). Change in Q value was significantly less in the aspheric group (0.53 ± 0.31) than the wavefront-guided group (0.91 ± 0.30) (P < .01). The aspheric group had significant improvement in contrast sensitivity at all spatial frequencies (P < .01), whereas the wavefront-guided group showed a slight decrease at higher spatial frequency (18 cycles per degree). CONCLUSIONS: Aspheric LASIK induced significantly less change in higher-order aberrations and maintained corneal asphericity better than wavefront-guided LASIK. The visual outcome and contrast sensitivity was better in the aspheric group at 6 months postoperatively.

Unlocking prophage potential: In silico and experimental analysis of a novel Mycobacterium fortuitum LysinB containing a peptidoglycan-binding domain.

Endolysins are highly evolved bacteriophage-encoded lytic enzymes produced to damage the bacterial cell wall for phage progeny release. They offer promising potential as highly specific lytic proteins with a low chance of bacterial resistance. The diversity in lysin sequences and domain organization can be staggering. In silico analysis of bacteriophage and prophage genomes can help identify endolysins exhibiting unique features and high antibacterial activity, hence feeding the pipeline of narrow-spectrum protein antibiotics. Mycobacteriophage lysis cassettes mostly have two lytic enzymes, LysinA and LysinB. The enzyme LysinA targets peptidoglycan in the cell wall and possesses a modular architecture. LysinB typically contains a single domain and acts upon the mycolyl ester linkages in mycolyl-arabinogalactan-peptidoglycan (Payne et al., 2010). This study aimed to find novel LysinBs against Mycobacterium fortuitum. After a detailed in silico characterization of lysis cassettes from three M. fortuitum prophages, we chose to work on a LysinB (hereafter described as LysinB_MF) found in an incomplete prophage (phiE1336, 9.4 kb in strain E1336). LysinB_MF showed low sequence similarity with any other endolysins in the database and formed a separate clade on phylogenetic analysis. LysinB_MF's structure, extracted from the AlphaFold Protein Structure Database, demonstrated a modular architecture with two structurally distinct domains: a peptidoglycan-binding domain (PGBD) at the N-terminal and the characteristic alpha/beta hydrolase domain connected via a linker peptide. We found the alpha/beta hydrolase domain, which is the enzyme-active domain (EAD), contains the conserved Ser-Asp-His catalytic triad with a tunnel-like topology and forms intermolecular hydrogen bonds. The PGBD shows structural similarity to the cell-wall binding domain of an amidase from Clostridium acetobutylicum, hinting at its acquisition due to domain mobility. Our in silico electrostatic potential analysis suggested that PGBD might be essential to the enzyme activity. This was experimentally validated by generating a truncated version of the enzyme, which demonstrated about six-fold decreased activity compared to its native form. The antimycobacterial activity of this enzyme was also compromised in its absence. Based on our analysis, PGBD emerged as an integral constituent of enzymes with diverse functional properties and is predicted to be a conserved cross-kingdom. Overall, this study highlights the importance of mining mycobacterial prophages as a novel endolysin source. It also provides unique insights into the diverse architecture of mycobacteriophage-encoded endolysins and the importance of functional domains for their catalytic activities.

Study of biomarkers p53, Ki-67, Bcl-2, and VEGF in pterygium.

PURPOSE: To study the biomarkers present in primary pterygium samples of patients of Indian ethnicity and compare it with the samples obtained from the unaffected conjunctiva of the same eye. METHODS: A prospective case-control study of 17 eyes in patients above 10 years of age with primary pterygium who underwent pterygium excision using limbal conjunctival autograft technique. The pterygium samples (cases) and conjunctival samples (controls) were sent for immunohistochemical (IHC) staining for the following biomarkers: p53, Bcl-2, Ki-67, and vascular endothelial growth factor (VEGF). RESULT: The immunohistochemistry of the samples and the controls revealed p53 positivity in 47.05% of pterygium samples and 29.4% of controls ( P < 0.587). Nine cases each in pterygium and control samples were positive for Ki-67 expression. Differences in the staining pattern between the two groups were not statistically significant ( P < 1.000). Bcl-2 positivity was seen in 10 pterygium samples (58.8%) and 12 controls (70.5%), with no statistical difference between the two groups ( P < 0.455). VEGF expression was seen in both epithelial and endothelial cells of the samples and controls, with no statistical difference between the two groups, with P = 1.000 for the epithelial staining and P = 0.637 for endothelial staining. CONCLUSION: The expression of biomarkers was comparable in both groups. We conclude that pterygium, against common belief, might not be a localized disease process but a global ocular phenomenon where the apparently healthy tissue also has some ongoing disease process at a molecular level.

Role of corneal collagen cross-linking in pseudophakic bullous keratopathy: a clinicopathological study.

OBJECTIVE: To evaluate the clinical and histopathologic changes induced by collagen cross-linking (CXL) in pseudophakic bullous keratopathy (PBK). DESIGN: Randomized, prospective, interventional study. PARTICIPANTS: Twenty-four patients with PBK were included in the study. METHODS: Twenty-four patients with PBK underwent CXL followed by keratoplasty at 1 or 3 months. Twelve patients underwent penetrating keratoplasty 1 month after CXL (group A) and the remaining 12 patients underwent penetrating keratoplasty 3 months after CXL (group B). The main outcome measures were assessed at 1 week and 1 month for all patients and at 3 months for 12 patients only. The corneal buttons underwent histopathologic and immunofluorescence evaluation. MAIN OUTCOME MEASURES: Visual acuity, ocular discomfort (tearing, redness, pain), corneal haze, central corneal thickness, histopathologic evaluation, and immunofluorescent microscopy. RESULTS: Mean visual acuity showed a significant improvement after CXL, from 1.925 ± 0.173 before surgery to 1.75±0.296 at 1 month after surgery (P = 0.010), but deteriorated to 1.81 ± 0.23 at 3 months. Symptomatic relief after CXL was at a maximum at 1 month, with a worsening trend at 3 months. Eighteen patients showed a reduction in corneal haze 1 month after CXL. The effect was maintained in 9 of 12 patients at 3 months. The mean central corneal thickness decreased significantly from 846.46 ± 88.741 to 781.0 ± 98.788 µm at 1 month (P<0.01) after CXL, but increased to 805.08±136.06 µm at 3 months. Immunofluorescence microscopy revealed anterior stromal compaction in 7 of 12 patients (58.3%) in group A and in 5 of 12 patients (41.6%) in group B. Staining of keratocyte nuclei with 4',6-diaminido-2-phenylindole dihydrochloride (Molecular Probes, Carlsband, CA) revealed a relative uniform distribution throughout the stroma. CONCLUSIONS: Collagen cross-linking causes symptomatic relief and a decrease in central corneal thickness and anterior stromal compaction in PBK. However, the effect decreases with time and depends on disease severity.

Evaluation of pattern ERG as a visual prognosticator in chiasmatic tumours.

BACKGROUND: Tumours compressing the optic pathway may lead to irreversible loss of vision that can be detected by pattern electroretinogram owing to its relation to ganglion cell function. This study aims to assess whether pattern electroretinogram is a useful tool to predict visual outcome following decompressive surgery for sellar and parasellar tumours. DESIGN: Prospective, non-randomized study. PARTICIPANTS: Forty eyes of 20 patients with radiologically confirmed tumours in and around the sellar region. METHODS: Patients were followed for 6 weeks following surgical intervention (transphenoidal or transfrontal approach). MAIN OUTCOME MEASURES: Best-corrected visual acuity, visual fields (Humphrey 30-2 standard automated perimetry) and pattern electroretinogram. The ratio N95/P50 (N2/P1) was calculated for each recording. RESULTS: There was improvement in visual fields in 35.4% eyes with normal n2/p1 ratio (>1.1) as compared to 22.2% with abnormal ratio. Also, 9.6% eyes with normal ratio and 11.1% with an abnormal ratio deteriorated postoperatively. No association was found between pattern electroretinogram and visual fields preoperatively and postoperatively (P = 0.093). CONCLUSIONS: Pattern electroretinogram may not be a useful prognostic indicator in the preoperative assessment of tumours causing chiasmal compression. An abnormal N2/P1 ratio is not necessarily associated with lesser or no clinical improvement following surgery as compared to an eye with a normal pattern electroretinogram.

Self-inflicted bilateral ocular injury with scissors in a psychiatric patient.

A young male was brought to the ophthalmic emergency by his family with severe bleeding from both eyes after self-inflicted injury with scissors in a fit of mania. He had a history of schizophrenia and has been on irregular treatment for the past 10 years. Both eyes were severely damaged with avulsion of all extraocular muscles in one eye and a large corneoscleral laceration in the other. We report this unique case of oedipism or self-enucleation where a sharp instrument was used. Self-inflicted injury to the eyes is a rather uncommon phenomenon described in psychiatric patients. It can range from minor abrasions to severe ocular mutilation and loss of sight. The strict observation of these patients while admitted to the hospital and a multidisciplinary approach to ensure their future safety are imperative.

Repeat deep anterior lamellar keratoplasty (DALK) for failed primary DALK.

Purpose: To evaluate the effectiveness of repeat deep anterior lamellar keratoplasty (DALK) in patients of previous failed DALK. Methods: : A retrospective analysis of records of seven patients who had undergone repeat DALK following the failure of the primary DALK was done. The indications for repeat surgery, time elapsed since the first surgery, and pre- & postoperative best-corrected visual acuity (BCVA) were noted for all the patients. Results: The follow-up period ranged between one- to four-year post repeat DALK. The indication of primary DALK was keratoconus with vernal keratoconjunctivitis (VKC) (n = 3), corneal amyloidosis (n = 2), Salzman nodular keratopathy (n = 1), and healed keratitis (n = 1). The need for repeat surgery arose when the BSCVA dropped to less than 20/200. The time interval elapsed since the first surgery ranged from two months to four years. Postoperatively, the BSCVA improved from 20/120 to 20/30 at the end of one-year post repeat DALK in all except one patient. All regrafts were clear at the most recent examination, performed after a mean period of 18 months after the secondary graft. No complication was encountered during the resurgery. The dissection of the host bed was easier in the second surgery owing to weaker adhesions. Conclusion: The prognosis for repeat DALK for failed DALK is excellent, and the outcomes of secondary grafts were comparable to those of primary DALK grafts. Re DALK offers the advantage of an easier dissection and lower chances of graft rejection compared to penetrating keratoplasty.

Orbital and ocular perfusion in thyroid eye disease.

Thyroid eye disease (TED) is characterized by enlargement of extraocular muscles, an increase in retrobulbar fat, orbital fibrosis, and fluctuations in plasma thyroid hormone levels in most patients, often associated with raised autoantibody titers. The occurrence of orbital space conflict compromises the orbital perfusion, unchecked progression of which results in irreversible loss of visual acuity and visual fields. The quantitative assessment of orbital perfusion can be done by measurement of blood flow velocities in the superior ophthalmic vein (SOV), ophthalmic artery (OA), central retinal artery (CRA), and posterior ciliary artery by color Doppler imaging. The retinal and choroidal microvasculature is studied by optical coherence tomography and optical coherence tomography angiography. The orbital and ocular perfusion fluctuates during the course of TED. Orbital congestion is reflected by the reduction or reversal of SOV flow and an increase in subfoveal choroidal thickness. The active phase is characterized by high blood flow velocities of the OA and CRA. The onset of dysthyroid optic neuropathy is associated with reduced arterial perfusion and reduction in parafoveal and peripapillary vascular density. Orbital decompression improves the SOV flow and decreases the resistivity index of CRA. Sequential evaluation of orbital hemodynamic changes can thus supplement the clinical scoring systems for monitoring and planning intervention in TED.