Repeated Lacrimal Gland Biopsies.

PURPOSE: To examine the indications for repeated lacrimal gland biopsies, and the rate of detection of a new diagnosis. METHODS: A single-center, retrospective review of patients who underwent more than 1 lacrimal gland biopsy, either ipsilateral or contralateral, between 2000 and 2022. RESULTS: One hundred and twenty-three patients (80 female; 65%) had repeated lacrimal gland biopsy. The commonest diagnosis on initial biopsy was chronic nonspecific dacryoadenitis (NSD) (49/123; 40%). Indications for repeated biopsy were uncertainty in making a histopathological diagnosis (16/123; 13%), poorly-responsive or recurrent ipsilateral disease (61/123; 50%), new or continued/worsening contralateral disease (30 patients; 24%), and planned tumor resection after initial biopsy (16/123; 13%). Of the 40 patients (33%) with a different histopathological diagnosis after repeated lacrimal biopsy, 4 (10%) had lymphoma, initially reported as NSD (4/49 with NSD; 8%), and 7/40 (18%) (14% of the 49 NSD patients) were reclassified as having specific inflammations (including 2 with granulomatous polyangiitis); of the 7 having reclassification as a specific dacryoadenitis, 6/7 had ipsilateral disease failing to respond to primary treatment, and 1/7 had new onset or progression of contralateral disease. All histology after the primary biopsy of 16 patients with lacrimal gland malignancies retained the same tissue diagnosis. CONCLUSION: Repeated biopsy for lacrimal gland disease in this study revealed a diagnosis of malignancy in 20%, including lymphoma in 8% of those initially diagnosed with NSD. There was a 14% rate of diagnostic progression from "non-specific" dacryoadenitis to a more specific inflammatory disease.

Visual deterioration in patients with photoreceptor loss after retinal reattachment surgery.

PURPOSE: Assess the relationship between photoreceptor degeneration and visual function after retinal reattachment surgery (RRS) in a prospective cohort. METHODS: Patients with rhegmatogenous retinal detachment (RRD) were reviewed before and 6 months after vitreoretinal surgery. Optical coherence tomographical thickness of the outer nuclear layer (ONL), outer retinal segment (ORS), retinal pigmented epithelium to ellipsoid zone (RPE-EZ) and external limiting membrane to EZ (ELM-EZ) were recorded 6 months post-operatively. These were compared to best corrected visual acuity (BCVA) and retinal sensitivity (Humphrey visual field). RESULTS: Thirteen macula-off and 8 macula-on RRD patients were included. The mean ONL thickness was higher after macula-on RRD compared to macula-off RRD (97.70 ± 3.62 µm vs. 73.10 ± 4.98 µm). In all RRD eyes, every 1 µm decrease in ONL thickness correlated with a 0.052 dB decrease and in retinal sensitivity and every 1 µm decrease in ORS thickness was associated with a 0.062 dB reduction in retinal sensitivity. ORS, ELM-EZ and RPE-EZ thickness did not correlate with BCVA post-RRS. CONCLUSION: There was greater ONL and ORS thinning following macula-off compared to macula-on RRD. Correlations between ONL and ORS thinning with decreased retinal sensitivity may be explained by RRD-induced photoreceptor death.

Current advances in giant cell arteritis.

PURPOSE OF REVIEW: The aim of this study was to present the latest advances in giant cell arteritis (GCA) care, and recent national and international rheumatology societies guidance which influences clinical practice. RECENT FINDINGS: Cranial ultrasound reduces diagnostic delay and improves clinical outcomes. Immediate high dose glucocorticoids remain the standard treatment for GCA. Controlled trial evidence using Tocilizumab, an interleukin-6 receptor antagonist, shows good clinical efficacy with steroid-sparing effects. SUMMARY: Improved patient outcomes require formalizing pathways to diagnosis and closer liaison with rheumatology for long-term management with second-line therapies.

Myelin Oligodendrocyte Glycoprotein Antibody-Associated Optic Neuritis-A Review.

ABSTRACT: Our understanding of demyelinating optic neuritis has substantially evolved over the past 2 decades. With advancements in serological testing, antibodies against myelin oligodendrocyte glycoprotein (MOG) have been recently discovered in a distinct subset of demyelinating neuroinflammatory disease. Although MOG-immunoglobulin G (IgG)-associated disorder (MOGAD) has previously been seen as a component of neuromyelitis optica spectrum disorder (NMOSD), evidence increasingly suggests that it should be distinguished as a separate condition. The distinction of MOGAD from aquaporin-4 IgG NMOSD is imperative as treatment plans need to be tailored to its unique disease course and prognosis. The purpose of this review is to explore the nature and outcomes of MOGAD optic neuritis to help guide acute and long-term immunosuppressive treatment decisions.

Genotypic diversity in multi-drug-resistant E. coli isolated from animal feces and Yamuna River water, India, using rep-PCR fingerprinting.

Genotypic diversity among multi-drug-resistant (MDR) aquatic E. coli isolated from different sites of Yamuna River was analyzed using repetitive element PCR (rep-PCR) methods viz. ERIC-PCR and (GTG)5-PCR and compared with the MDR animal fecal isolates. The 97 E. coli isolates belonging to different serotypes, phylogroups, and multi-drug resistance patterns were analyzed. High genetic diversity was observed by both the methods; however, (GTG)5 typing showed higher discriminating potential. Combination of ERIC types (E1-E32) and (GTG)5 types (G1-G46) generated 77 genotypes. The frequency of genotypes ranged from 0.013 to 0.065. The genotype composition of E. coli isolates was highly diverse at all the sampling sites across Yamuna River except at its entry site in Delhi. The sampling sites under the influence of high anthropogenic activities showed an increase in number of unique genotype isolates. These sites also exhibited high multiple antibiotic resistance (MAR) indexes (above 0.25) suggesting high risk of contamination. Principal coordinate analysis (PCoA) showed limited clustering of genotypes based on the sampling sites. The most frequent genotypes were grouped in the positive zone of both the principal coordinates (PC1 and PC2). The genotypes of most of the animal fecal isolates were unique and occupied a common space in the negative PC1 area forming a separate cluster. High genotypic diversity among the aquatic E. coli and the drain isolates, discharging the untreated municipal waste in the river, was observed, suggesting that the sewage effluents contribute substantially to contamination of this river system than animal feces. The presence of such a high diversity among the MDR E. coli isolates in the natural river systems is of great public health significance and highlights the need of an efficient surveillance system for better management of Indian natural water bodies.

Safety and Efficacy of Mucograft Porcine Collagen Bioengineered Acellular Dermal Matrix as a Spacer Graft in Lower Eyelid Elevation Surgery.

Background: Recent regulatory changes have limited the access to a widely used commercially available bioengineered acellular dermal matrix (BADM) product as a spacer graft in the surgical correction of lower eyelid retraction. We report our off-label usage of Mucograft, a porcine BADM, as an alternative BADM. Methods: A retrospective review was conducted of patients undergoing bilateral lower lid surgery with Mucograft (12 eyes) at a single institution. Results: For the six patients, there was a mean lower lid elevation of 1.93 mm, without any serious complications. There was greater elevation of the lower lid position for the Mucograft group compared with four septo-retractor control patients (1.93 versus 0.94mm, P = 0.008). Conclusion: Mucograft performed satisfactorily, and further investigation is warranted regarding its longer-term safety and efficacy.

Starch and storage protein dynamics in the developing and matured grains of durum wheat and diploid progenitor species.

Durum wheat, less immunogenically intolerant than bread wheat, originates from diploid progenitors known for nutritional quality and stress tolerance. Present study involves the analysis of major grain parameters, viz. size, weight, sugar, starch, and protein content of Triticum durum (AABB genome) and its diploid progenitors, Triticum monococcum (AA genome) and Aegilops speltoides (BB genome). Samples were collected during 2-5 weeks after anthesis (WAA), and at maturity. The investigation revealed that T. durum displayed the maximum grain size and weight. Expression analysis of Grain Weight 2 (GW2) and Glutamine Synthase (GS2), negative and positive regulators of grain weight and size, respectively, revealed higher GW2 expression in Ae. speltoides and higher GS2 expression in T. durum. Further we explored total starch, sugar and protein content, observing higher levels of starch and sugar in durum wheat while AA genome species exhibited higher protein content dominated by the fractions of albumin/globulin. HPLC profiling revealed unique sub-fractions in all three genome species. Additionally, a comparative transcriptome analysis also corroborated with the starch and protein content in the grains. This study provides valuable insights into the genetic and biochemical distinctions among durum wheat and its diploid progenitors, offering a foundation for their nutritional composition.

Blood-stained tears-a red flag for malignancy?

BACKGROUND: Blood-stained tears can indicate occult malignancy of the lacrimal drainage apparatus. This study reviews data on patients presenting with blood in their tears and the underlying cause for this rare symptom. METHODS: Patients presenting with blood in their tears, identified over a 20-year period, were retrospectively collected from a single tertiary ophthalmic hospital's database and analysed. RESULTS: 51 patients were identified, the majority female (58%) with a mean age of 55 years. Most cases were unilateral (96%) with blood originating from the nasolacrimal drainage system in 53%. The most common diagnosis for blood-stained tears was a lacrimal sac mucocele (n = 16) followed by a conjunctival vascular lesion (n = 4). Three patients had systemic haematological disorders. The rate of malignancy was 8% (n = 4), with 2 patients having lacrimal sac transitional cell carcinomas, one with a lacrimal sac plasmacytoma and the other with chronic lymphocytic leukaemia and bilateral orbital infiltration (with bilateral bloody tears). One patient had a lacrimal sac inverted papilloma, a premalignant lesion. Four patients had benign papillomas (of the lacrimal sac, conjunctiva and caruncle). CONCLUSION: Haemolacria was a red flag for malignancy in 8% of patients (and tumours in 18% of patients). A thorough clinical examination including lid eversion identified a conjunctival, caruncle, eyelid or canalicular cause in 27% of cases.

Understanding plant-microbe interaction of rice and soybean with two contrasting diazotrophic bacteria through comparative transcriptome analysis.

Understanding the beneficial plant-microbe interactions is becoming extremely critical for deploying microbes imparting plant fitness and achieving sustainability in agriculture. Diazotrophic bacteria have the unique ability to survive without external sources of nitrogen and simultaneously promote host plant growth, but the mechanisms of endophytic interaction in cereals and legumes have not been studied extensively. We have studied the early interaction of two diazotrophic bacteria, Gluconacetobacter diazotrophicus (GAB) and Bradyrhizobium japonicum (BRH), in 15-day-old seedlings of rice and soybean up to 120 h after inoculation (hai) under low-nitrogen medium. Root colonization of GAB in rice was higher than that of BRH, and BRH colonization was higher in soybean roots as observed from the scanning electron microscopy at 120 hai. Peroxidase enzyme was significantly higher at 24 hai but thereafter was reduced sharply in soybean and gradually in rice. The roots of rice and soybean inoculated with GAB and BRH harvested from five time points were pooled, and transcriptome analysis was executed along with control. Two pathways, "Plant pathogen interaction" and "MAPK signaling," were specific to Rice-Gluconacetobacter (RG), whereas the pathways related to nitrogen metabolism and plant hormone signaling were specific to Rice-Bradyrhizobium (RB) in rice. Comparative transcriptome analysis of the root tissues revealed that several plant-diazotroph-specific differentially expressed genes (DEGs) and metabolic pathways of plant-diazotroph-specific transcripts, viz., chitinase, brassinosteroid, auxin, Myeloblastosis (MYB), nodulin, and nitrate transporter (NRT), were common in all plant-diazotroph combinations; three transcripts, viz., nitrate transport accessory protein (NAR), thaumatin, and thionin, were exclusive in rice and another three transcripts, viz., NAC (NAM: no apical meristem, ATAF: Arabidopsis thaliana activating factor, and CUC: cup-shaped cotyledon), ABA (abscisic acid), and ammonium transporter, were exclusive in soybean. Differential expression of these transcripts and reduction in pathogenesis-related (PR) protein expression show the early interaction. Based on the interaction, it can be inferred that the compatibility of rice and soybean is more with GAB and BRH, respectively. We propose that rice is unable to identify the diazotroph as a beneficial microorganism or a pathogen from an early response. So, it expressed the hypersensitivity-related transcripts along with PR proteins. The molecular mechanism of diazotrophic associations of GAB and BRH with rice vis-à-vis soybean will shed light on the basic understanding of host responses to beneficial microorganisms.

Ocular findings in patients with polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes syndrome.

OBJECTIVE: Polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes (POEMS) syndrome is a rare disorder. This study investigated the types of ocular signs and symptoms in patients with POEMS and any systemic factors that may be associated with development of such ocular findings. DESIGN: Case series from tertiary referral center. PARTICIPANTS: A total of 33 patients with POEMS syndrome underwent at least 1 ophthalmologic examination and were included in the study. METHODS: A 10-year retrospective chart review of patients diagnosed with POEMS syndrome was performed. MAIN OUTCOME MEASURES: Visual symptoms, visual acuity, presence of optic disc edema (ODE), and levels of systemic factors (including plasma vascular endothelial growth factor [VEGF], plasma interlukin-6 [IL-6], and raised intracranial pressure) and their relationship to ODE. RESULTS: Five of the patients (15%) reported diplopia, 15 patients (45%) had blurred vision, and 3 patients (9%) had ocular pain. The most common ocular finding was bilateral ODE in 17 patients (52%). Of the patients with ODE, 5 (29%) were asymptomatic at the first ocular examination. Among patients with ODE, there was a significant difference (P = 0.03) between the mean plasma VEGF level at the time of diagnosis of the ODE compared with when the ODE resolved. There was no difference in plasma IL-6 levels between people with and without ODE. Patients with ODE had a higher mean lumbar puncture opening pressure (276±14 mm H(2)O; normal range, 100-250 mm H(2)0) than patients without ODE, although the difference was not statistically significant (P = 0.08). CONCLUSIONS: Optic disc edema is a common finding in patients with POEMS. Because patients can be asymptomatic, eye examinations should be performed in all patients with POEMS. There may be an association between elevated VEGF and intracranial pressure and ODE; further studies are required.

Integration of Dual Stress Transcriptomes and Major QTLs from a Pair of Genotypes Contrasting for Drought and Chronic Nitrogen Starvation Identifies Key Stress Responsive Genes in Rice.

We report here the genome-wide changes resulting from low N (N-W+), low water (N+W-)) and dual stresses (N-W-) in root and shoot tissues of two rice genotypes, namely, IR 64 (IR64) and Nagina 22 (N22), and their association with the QTLs for nitrogen use efficiency. For all the root parameters, except for root length under N-W+, N22 performed better than IR64. Chlorophyll a, b and carotenoid content were higher in IR64 under N+W+ treatment and N-W+ and N+W- stresses; however, under dual stress, N22 had higher chlorophyll b content. While nitrite reductase, glutamate synthase (GS) and citrate synthase assays showed better specific activity in IR64, glutamate dehydrogenase showed better specific activity in N22 under dual stress (N-W-); the other N and C assimilating enzymes showed similar but low specific activities in both the genotypes. A total of 8926 differentially expressed genes (DEGs) were identified compared to optimal (N+W+) condition from across all treatments. While 1174, 698 and 903 DEGs in IR64 roots and 1197, 187 and 781 in N22 roots were identified, nearly double the number of DEGs were found in the shoot tissues; 3357, 1006 and 4005 in IR64 and 4004, 990 and 2143 in N22, under N-W+, N+W- and N-W- treatments, respectively. IR64 and N22 showed differential expression in 15 and 11 N-transporter genes respectively, under one or more stress treatments, out of which four showed differential expression also in N+W- condition. The negative regulators of N- stress, e.g., NIGT1, OsACTPK1 and OsBT were downregulated in IR64 while in N22, OsBT was not downregulated. Overall, N22 performed better under dual stress conditions owing to its better root architecture, chlorophyll and porphyrin synthesis and oxidative stress management. We identified 12 QTLs for seed and straw N content using 253 recombinant inbred lines derived from IR64 and N22 and a 5K SNP array. The QTL hotspot region on chromosome 6 comprised of 61 genes, of which, five were DEGs encoding for UDP-glucuronosyltransferase, serine threonine kinase, anthocyanidin 3-O-glucosyltransferase, and nitrate induced proteins. The DEGs, QTLs and candidate genes reported in this study can serve as a major resource for both rice improvement and functional biology.

Evaluation of genetic diversity among aquatic and fecal isolates of Escherichia coli using multilocus variable number of tandem repeat analysis.

In developing countries like India, fecal pollution of surface waters is a major threat to public and environmental health. The aim of the study was to assess serological, phylogenetic and molecular diversity among aquatic Escherichia coli isolates from Yamuna river and their comparison with the animal fecal isolates. A total of 97 E. coli isolates from Yamuna river and domesticated animals were characterized by multilocus variable number tandem repeat analysis (MLVA) using four VNTR loci. The pathogenicity of these strains by serological and phylogenetic analysis was also determined. E. coli strains were differentiated into 53 distinct MLVA types with high discriminatory power, Simpson's index of 0.95 (95% CI 0.923-0.978). Cluster analysis and population modeling using minimum spanning tree suggested a possible epidemiological linkage among aquatic and fecal isolates. The study also reported the presence of highly diverse and pathogenic serotypes belonging to STEC and EPEC strains, particularly O157 and high prevalence of pathogenic phylogroups (phylogroup, B2 and D). The presence of such a high molecular heterogeneity among aquatic and fecal E. coli isolates emphasizes upon the need to develop proper fecal pollution abatement strategies for Indian natural bodies.

Transcriptome Analysis Reveals Important Candidate Genes Related to Nutrient Reservoir, Carbohydrate Metabolism, and Defence Proteins during Grain Development of Hexaploid Bread Wheat and Its Diploid Progenitors.

Wheat grain development after anthesis is an important biological process, in which major components of seeds are synthesised, and these components are further required for germination and seed vigour. We have made a comparative RNA-Seq analysis between hexaploid wheat and its individual diploid progenitors to know the major differentially expressed genes (DEGs) involved during grain development. Two libraries from each species were generated with an average of 55.63, 55.23, 68.13, and 103.81 million reads, resulting in 79.3K, 113.7K, 90.6K, and 121.3K numbers of transcripts in AA, BB, DD, and AABBDD genome species respectively. Number of expressed genes in hexaploid wheat was not proportional to its genome size, but marginally higher than that of its diploid progenitors. However, to capture all the transcripts in hexaploid wheat, sufficiently higher number of reads was required. Functional analysis of DEGs, in all the three comparisons, showed their predominance in three major classes of genes during grain development, i.e., nutrient reservoirs, carbohydrate metabolism, and defence proteins; some of them were subsequently validated through real time quantitative Reverse Transcription Polymerase Chain Reaction (qRT-PCR). Further, developmental stage-specific gene expression showed most of the defence protein genes expressed during initial developmental stages in hexaploid contrary to the diploids at later stages. Genes related to carbohydrates anabolism expressed during early stages, whereas catabolism genes expressed at later stages in all the species. However, no trend was observed in case of different nutrient reservoirs gene expression. This data could be used to study the comparative gene expression among the three diploid species and homeologue-specific expression in hexaploid.

High Prevalence of Antibiotic Resistance and Integrons in Escherichia coli Isolated from Urban River Water, India.

The contamination of surface waters with multidrug resistant (MDR) coliforms is a major public health concern in developing countries. This study was aimed to evaluate the occurrence of antibiotic resistance and role of integrons in the spread of resistance genes in Escherichia coli isolated from urban waters of river Yamuna. One hundred and forty-one strains of E. coli were isolated and assessed for antibiotic resistance wherein high resistance was observed for Cefazolin. Integrons (class 1 and class 2) were detected in 32% of the isolates. Variable region of class 1 integron carried different gene cassettes, namely. dfrA17-aadA5, dfrA12-orfF-aadA2, blaOXA-1-aadA1, and unusual phage tail tape measure protein. These integron-positive isolates were further characterized by phylogrouping, serotyping, and BOX-PCR typing. Phylogroup B2 was found to be the most prevalent. Pathogenic E. coli O157 was also reported. Majority of the isolates (54%; 7/13) carrying "dfrA17-aadA5" gene cassette were clustered predominantly into a single BOX-PCR type (B8), suggesting a genetic relatedness among the isolates. This study thus depicts very high incidence of multidrug resistance and class 1 integrons in surface water of India. The prevalence of integrons in aquatic E. coli correlated well with resistance to increasing number of antibiotic classes and multiple antibiotic resistance (MAR) index at various sites. Integron-positive MDR E. coli isolates were found to be serologically and genetically diverse suggesting major role of integrons in the emergence and dissemination of resistance traits in waterborne E. coli.

Integrons and antibiotic resistance genes in water-borne pathogens: threat detection and risk assessment.

Antibiotic-resistant genes (ARGs) are regarded as emerging environmental pollutants and pose a serious health risk to the human population. Integrons are genetic elements that are involved in the spread of ARGs amongst bacterial species. They also act as reservoirs of these resistance traits, further contributing to the development of multi-drug resistance in several water-borne pathogens. Due to inter- and intra-species transfer, integrons are now commonly reported in important water-borne pathogens such as Vibrio, Campylobacter, Salmonella, Shigella, Escherichia coli and other opportunistic pathogens. These pathogens exhibit immense diversity in their resistance gene cassettes. The evolution of multiple novel and complex gene cassettes in integrons further suggests the selection and horizontal transfer of ARGs in multi-drug resistant bacteria. Thus, the detection and characterization of these integrons in water-borne pathogens, especially in epidemic and pandemic strains, is of the utmost importance. It will provide a framework in which health authorities can conduct improved surveillance of antibiotic resistance in our natural water bodies. Such a study will also be helpful in developing better strategies for the containment and cure of infections caused by these bacteria.

Transcriptome data of cultivated tetraploid and hexaploid wheat variety during grain development.

Wheat is a major food crop and an important component of human diet throughout the world. There are two major types of cultivated wheat; one is tetraploid durum (pasta) wheat and another one is hexaploid bread wheat. Wheat grain is the reservoir of two major dietary components - carbohydrate and protein, which get accumulated during seed maturation and directly affects yield and quality. Hexaploid, having 6 copies of each chromosome differs to a great extent from tetraploid having 4 copies of each chromosome. Studying the gene expression pattern in developing grain would help in understanding the difference in metabolic process as well as involvement of the genes in these two types of wheat. A transcriptional comparison of developing grains was carried out between the two wheat genotypes; tetraploid (AABB:PDW233) and hexaploid (AABBDD:PBW343) using RNA-seq. Approximately 194 million raw reads were obtained from both libraries. After removal of contaminations, a huge proportion (>99%), of high quality reads were obtained, were aligned to reference genome. A total of 2324 up-regulated and 522 down-regulated genes were identified as differentially expressed between PDW233 vs PBW343. Gene ontology annotation and enrichment analysis gave further information about differentially expressed genes between durum and bread wheat. This information will help in understanding process grain reserve in tetraploid and hexaploid wheat in relation to their nutritional quality.

Integrons in Enterobacteriaceae: diversity, distribution and epidemiology.

Integrons are versatile gene acquisition systems that allow efficient capturing of exogenous genes and ensure their expression. Various classes of integrons possessing a wide variety of gene cassettes are ubiquitously distributed in enteric bacteria worldwide. The epidemiology of integrons associated multidrug resistance in Enterobacteriaceae is rapidly evolving. In the past two decades, the incidence of integrons in enteric bacteria has increased drastically with evolution of multiple gene cassettes, novel gene arrangements and complex chromosomal integrons such as Salmonella genomic islands. This review focuses on the distribution, versatility, spread and global trends of integrons among important members of the Enterobacteriaceae, including Escherichia coli, Klebsiella, Shigella and Salmonella, which are known to cause infections globally. Such a comprehensive understanding of integron-associated antibiotic resistance, their role in the spread of such resistance traits and their clinical relevance especially with regard to each genus individually is paramount to contain the global spread of antibiotic resistance.

A topographical relationship between visual field defects and optic radiation changes in glaucoma.

PURPOSE: To investigate the topographic relationship between glaucomatous retinal ganglion cell loss and changes in the optic radiation (OR) using diffusion tensor imaging (DTI). METHODS: A cross-sectional study was completed on nine patients with primary open angle glaucoma and nine age- and sex-matched controls. Glaucoma patients with binocular, symmetrical superior, or inferior visual hemifield defects were selected. A comparative DTI analysis was conducted between OR fibers connected to the affected and unaffected visual hemifield in the glaucoma group and corresponding OR in the control group. RESULTS: There was a significantly lower number of fiber bundles in the affected OR compared with unaffected OR and controls (P < 0.01). Radial diffusivity was similar between the affected and unaffected OR (P = 0.39), but higher in both groups compared with controls (P < 0.01). There was no difference in axial diffusivity among all groups. As a consequence, fractional anisotropy was lower and mean diffusivity was higher in the affected and unaffected OR compared with controls. CONCLUSIONS: A significant loss of OR fibers connected to the severely damaged part of the optic nerve head, but not the fibers connected to the relatively spared retinal hemifield shows a direct relationship between retinal neuronal damage and functionally connected OR fibers in glaucoma. However, OR fibers connected to the relatively preserved visual hemifield in the glaucoma subjects still showed changes in radial diffusivity compared with controls, suggesting possible early dysfunction. Our results support the notion that glaucoma is a neurodegenerative disease involving the posterior visual pathway.