Generation of two induced pluripotent stem cell lines (LVPEIi007-B, LVPEIi008-B) from patients harboring homozygous mutation in ABCA4 (c.6088C>T) using non-integrative Sendai virus-based approach.

Mutations in ABCA4 gene leads to the most common form of an inherited retinal disease namely, the Stargardt disease, type 1. Here, we report the generation of two different patient-specific induced pluripotent stem cell lines (LVPEIi007-B and LVPEIi008-B), carrying an identical homozygous mutation, (c.6088C>T) within the exon 44 of ABCA4 gene. These lines were generated by the reprogramming of patient-specific dermal fibroblasts, using the integration-free, Sendai viral vectors. Both lines were stably expanded and expressed the stemness and pluripotency markers, differentiated into cell types of all three germ layers, and maintained a normal karyotype.

Generation of two induced pluripotent stem cell lines (LVPEIi004-A and LVPEIi005-A) from probands with Leber Congenital Amaurosis 2 (LCA2) and harboring mutations in RPE65.

Leber Congenital Amaurosis 2 is an early onset retinal dystrophy that occurs due to mutation in RPE65 gene. Here, we report the generation of two patient specific induced pluripotent stem cell lines harboring nonsense mutations in exon 7 (c.646A > T) and exon 9 (c.992G > A) of RPE65 gene, respectively, which leads to premature translational termination and formation of defective protein. These lines were generated by the reprogramming of human dermal fibroblast cells using integration-free, episomal constructs expressing stemness genes. The stable lines maintained a normal karyotype, expressed the key stemness factors, underwent trilineage differentiation, and maintained their genetic identity and genomic integrity.

The role of CT-DCG in hardware - associated secondary acquired lacrimal duct obstruction: SALDO update study - (SUP) - Paper III.

Purpose: To study cases of hardware-associated secondary acquired lacrimal duct obstructions (SALDO) and the role of computed tomography dacryocystography (CT-DCG) scans in its diagnosis and management. Observations: Retrospective, interventional case review of four patients diagnosed as Hardware-associated SALDO, with primary maxillofacial repair performed elsewhere, were analyzed. The mean age was 36.5 years (range: 22-74 years), three of them being males. Left and right lacrimal systems were equally involved. Epiphora, swelling and discharge were the main presenting features. Three lacrimal sacs and nasolacrimal ducts on CT-DCG showed the screws of the orbital fracture plate directly piercing their walls, whereas a single case showed the sac displaced and pierced by the medial side of the orbital floor implant. Two cases underwent dacryocystorhinostomy with intubation, and the remaining two had to undergo dacryocystectomy due to extensive damage. Post-operatively all four cases were doing well at a mean follow-up of 2 months. Conclusions: The present series highlights the role of CT-DCG in delineating spatial relationship of lacrimal drainage system with the surrounding structures, facilitating planning as well as choice of surgery, and anticipating the intraoperative challenges. It also signifies importance of interdisciplinary coordination between oculoplastic and maxillofacial surgeons to avoid iatrogenic trauma to the lacrimal drainage system.

Delayed infections following polybutylate-coated polyester (Ethibond) suture frontalis suspension surgery for severe blepharoptosis.

PURPOSE: To describe the incidence and management of delayed infections following frontalis sling suspension with polybutylate-coated polyester suture (Ethibond). METHODS: Retrospective, interventional case series of 177 eyes of 150 patients, who underwent frontalis suspension surgery with Ethibond (Johnson and Johnson, USA), at L V Prasad Eye Institute, Hyderabad, India, between January 2016 and February 2022. Patients were assessed for chronic secondary sling infection, defined as infection/suture granuloma occurring beyond 6 weeks post-surgery. All patients received postoperative oral antibiotics. The clinical profile, microbiological evaluation, antibiotic sensitivity patterns, and management outcomes were analyzed. RESULTS: Delayed infection following Ethibond sling suspension was noted in 14 eyes of 13 patients (7.9%). Of these, eight cases (61.5%) were females. The average time interval from surgery to presentation was 7.5 months (range: 2.5 months to 2.5 years). Eleven eyes underwent sling removal. Of the three who received initial antibiotic course, two eventually needed sling removal. Microbiological evaluation was available in seven eyes (50%), with Staphylococcus aureus as the most common organism. Of the six positive cultures, five (83.3%) were resistant to fluoroquinolones (FQs). CONCLUSION: Frontalis suspension with Ethibond has an 8% incidence of delayed infections, with Staphylococcus aureus as the most common organism. The authors recommend early sling removal in all patients with infection and recommend consideration of an alternative material in the event of future revision surgery.

Thyroid Eye Disease: Pilot Study Comparison Between Patients in United States-Based and India-Based Practices.

PURPOSE: Thyroid eye disease (TED) phenotype varies by ethnicity/race and genetic/environmental factors. This study compared demographic and clinical characteristics of TED patients from the US and India. DESIGN: Observational pilot study . METHODS: Sixty-four patients with TED ages ≥18 years old with active disease (onset of symptoms ≤18 months or presenting clinical activity score (CAS) ≥4) were recruited between March and October 2021 from clinical practices in the United States (Philadelphia, PA) (n = 30) and India (Hyderabad, India) (n = 34). Data collection at baseline and 3 months included clinical measurements, thyroid disease history, and photographs. Ocular symptoms and quality of life data were obtained by phone interview. CAS was calculated using the standard 7-point scale. RESULTS: There was no statistically significant difference in age, TED duration, or smoking status between patient groups. Both groups had good vision, a low rate of optic neuropathy, and comparable exophthalmometry. US patients were predominantly female (86.7% [26/30]), with a history of hyperthyroidism (96% 29/30). In comparison, Indian patients were 52.9% (18/34, P = .004) female; underlying thyroid disease was distributed between hyperthyroidism (52%), hypothyroidism (17.6%) and euthyroid (9.7%). Mean (SD) CAS in the US cohort was double the score in the India cohort (4.2 (1.7) vs 1.65 (1.7), respectively) (P < .0001). However, patients at both sites experienced subjective symptoms of TED at a similar frequency. CONCLUSIONS: Observed differences in TED between US and Indian patients warrant further investigation to elucidate differences in pathogenesis, disease expression, or other factors that may influence TED in diverse populations.

Generation of Leber congenital amaurosis, type 12 patient-specific induced pluripotent stem cell line (LVPEIi006-A), harboring a homozygous mutation in RD3.

Leber congenital amaurosis (LCA) is a congenital, early onset, autosomal recessive inherited retinal disease (IRD). This report describes an LCA12 patient-specific iPSC line (LVPEIi006-A), generated by the reprogramming of dermal fibroblasts using integration-free episomal plasmids.This disease-specific iPSC model carries a homozygous point mutation in RD3, within the donor splice site at the end of exon 2 (c.296 + 1G > A). The stable line at passage 15 has displayed a normal colony morphology, expressed multiple stemness and pluripotency markers, lost all transgenes, differentiated into cell types of all three germ layers, and maintained a normal karyotype.

Eyelid Surgery in Thyroid Eye Disease.

PURPOSE: To review and summarize a comprehensive synopsis of surgery of the eyelid in thyroid eye disease (TED). METHODS: A PubMed search for specific eyelid manifestations of TED was performed. Studies reporting surgical management of these were reviewed, along with the author's own experience. RESULTS: The most common eyelid manifestations of TED include eyelid retraction, blepharoptosis, entropion, and epiblepharon, with most of them requiring surgical intervention. The correction of eyelid retraction has received maximum attention, with several surgical techniques that have stood the test of time. Blepharoptosis in TED that requires surgical intervention is usually aponeurotic. Entropion and Epiblepharon are rare in TED, and may resolve spontaneously, or following orbital decompression. CONCLUSIONS: Retraction is the commonest eyelid manifestation of TED, with multiple surgical options available for its correction. Blepharoptosis, entropion, and epiblepharon are rare eyelid findings in TED, that may occasionally require surgical correction.

Rapid arsenite oxidation by Paenarthrobacter nicotinovorans strain SSBW5: unravelling the role of GlpF, aioAB and aioE genes.

A novel arsenite resistant bacterial strain SSBW5 was isolated from the battery waste site of Corlim, Goa, India. This strain interestingly exhibited rapid arsenite oxidation with an accumulation of 5 mM arsenate within 24 h and a minimum inhibitory concentration (MIC) of 18 mM. The strain SSBW5 was identified as Paenarthrobacter nicotinovorans using 16S rDNA sequence analysis. Fourier-transformed infrared (FTIR) spectroscopy of arsenite-exposed cells revealed the interaction of arsenite with several important functional groups present on the cell surface, possibly involved in the resistance mechanism. Interestingly, the whole genome sequence analysis also clearly elucidated the presence of genes, such as GlpF, aioAB and aioE encoding transporter, arsenite oxidase and oxidoreductase enzyme, respectively, conferring their role in arsenite resistance. Furthermore, this strain also revealed the presence of several other genes conferring resistance to various metals, drugs, antibiotics and disinfectants. Further suggesting the probable direct or indirect involvement of these genes in the detoxification of arsenite thereby increasing its tolerance limit. In addition, clumping of bacterial cells was observed through microscopic analysis which could also be a strategy to reduce arsenite toxicity thus indicating the existence of multiple resistance mechanisms in strain SSBW5. In the present communication, we are reporting for the first time the potential of P. nicotinovorans strain SSBW5 to be used in the bioremediation of arsenite via arsenite oxidation along with other toxic metals and metalloids.

A Novel and Low-cost Approach for Intravitreal Injection in an Experimental Model of Endophthalmitis.

Purpose: Animal models are necessary in understanding the pathogenesis of endophthalmitis and are also necessary to assist the development of new therapeutics for this sight-threatening ocular inflammation. Hamilton syringes are usually preferred to inject pathogens when performing experiments on test subjects, however, this method has technical and financial disadvantages. In this study, we report the findings and assess the related benefits of applying a novel low-cost intravitreal injection technique to initiate endophthalmitis in a mouse model while using the Eppendorf tip and a 26G needle. Methods: The 18-hr culture of clinical isolates of bacteria (Staphylococcus aureus and Pseudomonas aeruginosa) and fungus (Aspergillus flavus and Candida albicans) were resuspended to a final concentration of 10,000 colony forming units (CFU)/1 µL which were separately injected intravitreally into C57BL/6 mice (6-8 weeks) using a 0.1-2.5µL pipette attached to the modified Eppendorf tip with a 26G needle. The contralateral eye served as vehicle/uninjected control. Disease progression was determined by assessing the corneal haze, opacity, bacterial burden, and retinal histology of the eyes used in the model. Following euthanization, bacteria-infected mice were enucleated after 24 hr of the initial injection, and fungus-infected mice after 72 hr. Results: Of the 50 mice injected, the modified technique was successful in 48 mice. Two mice were excluded due to cataract formed by accidental injury to the lens. The experimental endophthalmitis mice model successfully mimicked the natural clinical course. Clinical assessment and histopathology confirmed the influx of inflammatory cells into the posterior segment of the eye along with dissolution of retinal architecture. Conclusion: Our novel method of injection using a modified Eppendorf tip and 26G needle yielded a cost-effective mouse model of clinical endophthalmitis, resulting in reproducible infection for understanding various aspects of its pathobiology.

Lower eyelid entropion following transconjunctival orbital fracture repair: Case series and literature review.

Lower eyelid malpositions following transconjunctival repair of the floor and the zygomaticomaxillary complex fractures are rarely observed. The case series includes three patients (mean age, 22 years; 3 males) who developed lower eyelid entropion following orbital fracture repair (two complexes, one isolated type) using titanium mesh (n = 2) or iliac bone grafting (n = 1) through the transconjunctival approach. Entropion repair was attempted with scar release and Jones procedure in one, and posterior lamellar lengthening with mucous membrane graft in two patients. At a median follow-up of 25 months (range, 3-24), two patients had symptomatic relief without any lash globe touch, and one patient had persistent entropion after multiple interventions including failed mucous membrane graft (n = 1), full-thickness blepharotomy with everting sutures (n = 1), and scleral spacer grafting for posterior lamellar lengthening (n = 1). The literature is inconclusive about the association between eyelid malpositioning and any specific implant material, type of fracture, or incision closure technique.

Single-stage upper eyelid switch flap for the repair of post-traumatic contracted socket and lower eyelid coloboma.

The use of eyelid switch flap in the correction of lower eyelid coloboma in a post-traumatic contracted socket is described. The lower eyelid, inferior fornix and lateral canthus were successfully created in a single stage with a switch flap from the upper eyelid. A satisfactory cosmetic outcome and a stable fornix for placement of a custom ocular prosthesis was achieved.

Giant jelly bump deposits on therapeutic contact lens: an unusual finding following ptosis surgery.

The authors report two cases of unusually large deposits on their therapeutic bandage contact lens (BCL) following uneventful surgery for congenital ptosis. The first case presented at 6 weeks with decreased vision, large jelly-bump deposits over the contact lens and sterile corneal infiltrates. The infiltrates rapidly resolved with restoration of vision following contact lens removal and topical antibiotics. The second case presented 2 weeks after surgery with visual loss and similar deposits but with no corneal involvement. Following replacement of BCL and topical lubricants, her vision improved to 20/20. Studies on the role of BCL in ptosis surgery are scarce with literature supporting its use for ocular surface protection and minimising postoperative discomfort. The authors hypothesise impaired blink mechanism as the accelerating factor for this unusual occurrence in the early postoperative period and recommend frequent replacement of the contact lens and a closer follow-up in all these cases.

Proteomic profiling of aspergillus flavus endophthalmitis derived extracellular vesicles in an in-vivo murine model.

Extracellular Vesicles (EVs) play pivotal roles in cell-to-cell communication, and are involved in potential pathological and physiological cellular processes. The aim of this study was to understand the proteomic cargo of these vesicles, in a murine model of Aspergillus flavus (AF) endophthalmitis. EVs were isolated from A. flavus infected C57BL/6 mice eyes by differential ultracentrifugation at 24 h post infection (p.i) and isolated EVs were characterized by Dynamic Light Scattering (DLS), Scanning Electron Microscopy (SEM), Exocet assay, and western blot. Proteomic profiling of EVs was then evaluated by mass spectrometry (LC-MS/MS) and compared it with control uninfected mice. The average size of the EVs were 180-280 nm by DLS and the number of EVs increased to 1.55 × 1010 in infected mice in comparison to EVs from uninfected eye (1.24 × 109). Western blot was positive for CD9, CD63, and CD81 confirming the presence of EVs. LC-MS/MS analysis, identified 81 differentially expressed proteins, of these 22 were up-regulated and 59 were down-regulated. Gene Ontology (GO) analysis revealed enrichment of lipid metabolism, protein complex binding, and transferase activity, and the proteins associated were Aquaporin-5, CD177 antigen, Solute carrier family-25, and Calcium/calmodulin-dependent protein kinase. Additionally, KEGG pathway analysis indicated that glucagon signalling, metabolic, and PPAR signalling pathway were significantly associated with EVs from A. flavus infected mice eyes. The protein cargo in EVs from A. flavus endophthalmitis provides new insights into the pathogenesis of fungal endophthalmitis and validation of these proteins can serve as diagnostic and/or prognostic biomarkers for patients with a clinical suspicion of fungal endophthalmitis. LAY SUMMARY: EVs play an important role in cell communication. In our study proteomic profiling of EVs isolated from A. flavus infected mice provided new insights into the understanding of the pathobiology of A. flavus endophthalmitis and validation of these proteins can serve as biomarkers.

Proteome profiling of Extracellular Vesicles in Pseudomonas aeruginosa endophthalmitis: Prognostic and therapeutic significance in a mouse model.

Endophthalmitis is a sight-threatening infection and a serious consequence of complications during intraocular surgery or penetrating injury of which Pseudomonas aeruginosa is an important etiology. Extracellular vesicles (EVs) have evolved as a promising entity for developing diagnostic and therapeutic biomarkers due to their involvement in intracellular communication and pathogenesis of diseases. We aimed to characterise the protein cargo of extracellular vesicles, isolated from a murine (C57BL/6) model of P. aeruginosa endophthalmitis by LC-MS/MS at 24 h post infection (p.i). EVs were extracted by ultracentrifugation, characterized by Dynamic Light Scattering (DLS) and western blotting with tetraspannin markers, CD9 and CD81 and quantified by the ExoCet quantification kit. Multiplex ELISA was performed to estimate the levels of TNF-α, IL-6, IFN-γ and IL-1ß. Proteomic analysis identified 2010 proteins (FDR ≤0.01) in EVs from infected mice eyes, of which 137 were differentially expressed (P-value ≤ 0.05). A total of 101 proteins were upregulated and 36 were downregulated. Additionally, 43 proteins were exclusive to infection set. KEGG and Gene Ontology revealed, Focal adhesion, Phagosome pathway, Complement cascade and IL-17 signalling pathway are crucial upregulated pathways involving proteins such as Tenascin, caveolin 1, caveolin 2, glutamine synthetase, microtubule-associated protein, C1, C8 and IL-17. Tenascin and caveolins are known to suppress anti-inflammatory cytokines further exacerbating the disease. The result of this study provides insight into the global extracellular vesicle proteome of P. aeruginosa endophthalmitis with their functional correlation and distinctive pattern of expression and tenascin, caveolin 1 and caveolin 2 are attractive biomarkers for P. aeruginosa endophthalmitis.

Neurotization of the human cornea - A comprehensive review and an interim report.

We present a comprehensive review of existing literature on surgical corneal neurotization (SCN) as a treatment modality for neurotrophic keratopathy (NK) with an interim report of seven cases where SCN was performed using the indirect approach and followed up till 18 months postoperatively to look for improvement in ocular surface, corneal sensations, and nerve regeneration by using in vivo confocal microscopy (IVCM). A literature search was performed for publications with keywords "corneal nerves," "neurotization," "esthesiometry," "corneal anesthesia," and "neurotrophic keratopathy." All literature available till December 31, 2020 was reviewed and included to describe NK and its management options, particularly SCN. NK is associated with absent or reduced corneal sensations and is managed using a step-ladder algorithm ranging from medical management for symptomatic relief to surgical corneal neurotization. Both direct and indirect approaches of SCN have a favorable outcome with reduced surgical morbidity in the indirect approach using sural nerve graft. Post neurotization, corneal sensation recovery may take up to 3-6 months, while nerve regeneration on confocal microscopy can take as long as 6 months-1 year.

Characterization and proteome profiling of extracellular vesicles in a murine model of Staphylococcus aureus endophthalmitis.

Endophthalmitis is a vision-threatening complication of intraocular surgery or penetrating injury of which Staphylococcus aureus is an important etiological agent. Extracellular vesicles (EVs) hold a tremendous possibility for developing diagnostic and therapeutic biomarkers due to their role in the pathogenesis of various infections. The aim of this study was to characterise the protein cargo of EVs, isolated from a murine (C57BL/6) model of S. aureus endophthalmitis by LC-MS/MS. Contralateral eye injected with sterile media served as control and both eyes were enucleated after 24 h, followed by extraction of EVs by ultracentrifugation. EVs were characterized by DLS and western blotting with tetraspanin markers, CD9 and CD81 and quantified by ExoCet quantification kit. Proteomic analysis identified 1964 proteins (FDR ≤ 0.01) in EVs from infected mice eyes, of which 40 proteins varied significantly in their amounts in comparison to EVs obtained from control eyeballs (P-value ≤ 0.05). The results of this study provide insight into the global EV proteome of S. aureus endophthalmitis with their functional correlation and differential protein amounts between infected and control set. Annexin A5, cathepsin D and C5a play a pivotal role in disease pathogenesis and could possibly play a role as a prognostic marker in endophthalmitis.

Proteomic profiling of exosomes in a mouse model of Candida albicans endophthalmitis.

Exosomes play pivotal roles in intercellular communication, and pathophysiological functions. In this study, we aimed to understand the role of exosomal proteome derived from C. albicans infected mice (C57BL/6) eyeball. Exosomes were characterized by Dynamic Light Scattering and Western blot, quantified and subjected to LC-MS/MS and cytokine quantification by ELISA. The average size of exosomes was 170-200 nm with number of exosomes amounted to 1.42 × 1010 in infected set compared to control (1.24 × 109). Western blot was positive for CD9, CD63 and CD81 confirming the presence of exosomes. IL-6, IL1ß, TNF-α, and IFN-γ levels were significantly elevated in infected eye at 72 h.p.i. Proteomic analysis identified 42 differentially expressed proteins, of these 37 were upregulated and 5 were downregulated. Gene Ontology (GO) revealed enrichment of cell adhesion, cytoskeleton organisation, and cellular response proteins such as aquaporin-5, gasdermin-A, CD5 antigen-like, Catenin, V-ATPase, and vesicle associated protein. Additionally, KEGG pathway analysis indicated the association of metabolic and carbon signalling pathways with exosomes from C. albicans infected eye. The protein cargo in exosomes released during endophthalmitis with C. albicans seems to play a unique role in the pathogenesis of the disease and further validations with larger cohort of patients is required to confirm them as biomarkers.

Local Infiltration Anesthesia for Orbital Exenteration in Patients With Rhino-Orbital Cerebral Mucormycosis: A Case Series.

Orbital exenteration is occasionally required for rhino-orbital cerebral mucormycosis. Multiple associated comorbidities can pose a risk for general anesthesia. There is only 1 report of exenteration being performed under trigeminal nerve block. We describe 5 patients who underwent orbital exenteration under local infiltration anesthesia with sedation. Patients and surgeons reported satisfactory conditions, with stable hemodynamics and successful day care management. Orbital exenteration under local infiltration anesthesia can be a safe and effective alternative for patients with rhino-orbital mucormycosis who are at risk with use of general anesthesia.

Methicillin resistance in Staphylococcus aureus modulates the transcriptome and disease pathology in a murine model of endophthalmitis.

The ever-increasing incidence of methicillin-resistant strains of Staphylococcus aureus (MRSA) endophthalmitis is of particular concern as they are associated with poor outcomes. To compare the histology and whole transcriptome of Methicillin resistant (MRSA) and Methicillin-susceptible (MSSA) Staphylococcus aureus endophthalmitis in an experimental murine model. MRSA and MSSA endophthalmitis was induced in C57BL/6 mice and disease progression was scored clinically and histologically at 24 h p.i. Retinal changes were monitored by H&E, CD45, MPO and GFAP staining followed by retinal cell death evaluation. Whole Transcriptome was analysed using the SuperPrint G3 Mouse Gene Expression v2 chip. Differential gene expression analysis (Limma package, R) was done followed by enrichment of pathways (KEGG database). Increased corneal haze, diminished vitreous clarity and red reflex was observed in MRSA infected mice eye compared to MSSA (p = 0.04). Histological assessment also corroborated with increased disease severity in MRSA (p = 0.02). Although MRSA infected eye displayed higher CD45+ cells and greater GFAP intensity, the difference was not statistically significant. However, higher retinal cell death was found to be associated with the MRSA infection (p = 0.007). Our study also revealed that MRSA infection induces changes in host transcriptome (FC = 1.5, p = 0.05), revealing the involvement of several interleukins (IL-11,15,10,1ra), chemokines (CCL-11, CXCL-1), Interferon receptors, GM-CSF, M-CSF, MMPs, Neruopilin2 (NRP-2), Ubiquitin associated peptidase and apoptotic ligands. ErbB signalling, JAK-STAT, adipocytokine and Ras signalling were the top divergently enriched pathways. Our study confirms the differential host immune response triggered by MRSA infection in the eye. Our study may help to elucidate the mechanisms of pathogenesis and to identify additional candidate drug targets for the treatment of MRSA endophthalmitis.

Retrobulbar Hyaluronidase Injection: Does It Reach the Eye?

PURPOSE: To determine if retrobulbar injection of hyaluronidase reaches the vitreous cavity, and to determine its concentration in the vitreous. METHODS: Prospective case-control study. Patients undergoing evisceration with implant for noninfective blind eyes were enrolled in the study. Before the evisceration, a retrobulbar injection of 3,000 IU of hyaluronidase (2 ml) was injected. Time from injection to in vivo sampling of posterior vitreous was noted. Vitreous samples from controls were obtained from patients undergoing vitrectomy for retinal detachment or diabetic retinopathy. Concentration of hyaluronidase was assessed in all 30 samples. An ELISA-based microtiter-technique was used to evaluate the activity of hyaluronidase by an avidin-peroxidase-based procedure using an ELISA reader. Incubations were carried out at room temperature and at 37°C. All the samples were analyzed in duplicates, and the mean of each sample was plotted on a scatter plot. RESULTS: Total of 30 vitreous samples were analyzed, of which 15 were controls and 15 were test samples. Of the 15 test samples, injection-to-sampling time was 0 to 20 minutes in 4 samples, 20 to 40 minutes in 6 samples, and 40 to 60 minutes in 5 samples. The highest concentration of hyaluronidase detected in control and test samples were 2.9 and 3.0 µg/ml, and the lowest concentration was 1.7 and 1.5 µg/ml (SD 0.3), respectively. There was no significant difference between control and test groups. CONCLUSION: Retrobulbar injection did not result in higher concentration of hyaluronidase in the posterior vitreous compared with controls when measured up to 60 minutes following injection.