Feasibility of Automated Gonioscopy Imaging in Clinical Practice.

PRCIS: Automated gonioscopy provided good-quality images of the anterior chamber angle. There was a short learning curve for operators, and the examination was well tolerated by patients. Patients expressed a preference for automated gonioscopy compared with traditional gonioscopy. PURPOSE: The purpose of this study was to assess the feasibility of using a desktop automated gonioscopy camera in glaucoma clinics by examining patient tolerability, ease of use, and image quality and comparing patient preference compared with traditional gonioscopy. PATIENTS AND METHODS: A prospective study was conducted in a university hospital clinic. Traditional gonioscopy was performed followed by imaging of the iridocorneal angle (ICA) using the Nidek GS-1 camera by 2 glaucoma specialists. Participants were asked to rate the comfort of automated gonioscopy and which method they preferred. The clinicians graded the ease of acquisition for each patient, and the image quality was reviewed by a grader. RESULTS: Forty-three eyes of 25 participants were included. Sixty-eight percent of participants viewed automated gonioscopy as "extremely comfortable," and the remainder reported it "comfortable". Forty percent preferred automated gonioscopy compared with traditional gonioscopy, while 52% were equivocal. Clinicians scored 32% of participants as "somewhat difficult" to the image. In 46% of eyes, good-quality photographs were obtained for 360 degrees of the ICA. Only 1 eye had no parts of the ICA clearly visible. Seventy-four percent of eyes had at least half of the ICA clearly visible in all 4 quadrants. CONCLUSION: Automated gonioscopy provided good-quality images of the ICA for most patients. It was often not possible to image the entire 360 degrees at the first attempt, but the examination was comfortable for patients, and only 8% preferred traditional gonioscopy to the automated photographic examination.

The relationship between multiple deprivation and severity of glaucoma at diagnosis.

BACKGROUND: Socioeconomic deprivation is associated with higher odds of chronic diseases, with many individuals living with more than one illness. This study aimed to examine the relationship between deprivation and severity of glaucoma at diagnosis, an important risk factor for glaucoma blindness. METHODS: A retrospective study of 472 consecutive patients referred by community optometrists to the glaucoma clinic at a university hospital was performed. Glaucoma severity was determined by standard automated perimetry mean deviation (MD) in the worse eye. The Scottish Index of Multiple Deprivation (SIMD) was determined for each patient as a measure of deprivation based on postcode. Regression analyses were performed to determine the relationship between visual field MD and SIMD. RESULTS: There was a significant relationship between higher levels of deprivation (lower SIMD) and worse severity of glaucoma at diagnosis. 32 of 472 patients (6.8%) had a MD of ≤-6 dB and 11 (2.3%) ≤-12 dB in their better eye. MD in the worse eye was 0.04 dB (95% CI 0.014 to 0.062 dB, P = 0.002) worse for each 100-point decrease in SIMD, with lower SIMD indicating a higher level of deprivation. A higher proportion of patients living in most deprived areas had a MD ≤ -6 dB or ≤ -12 dB at presentation compared to those living in the least deprived areas (14.3% versus 6.8% for ≤ -6 dB and 4.8% versus 0.8% for ≤ -12 dB). CONCLUSIONS: Higher levels of deprivation were associated with worse glaucoma severity at presentation. The reasons for poorer outcomes in those from more deprived communities need further study so that inequalities can be addressed and the frequency of patients presenting with advanced glaucoma reduced.

Feasibility and clinical utility of handheld fundus cameras for retinal imaging.

BACKGROUND/OBJECTIVES: Handheld fundus cameras are portable and cheaper alternatives to table-top counterparts. To date there have been no studies comparing feasibility and clinical utility of handheld fundus cameras to table-top devices. We compare the feasibility and clinical utility of four handheld fundus cameras/retinal imaging devices (Remidio NMFOP, Volk Pictor Plus, Volk iNview, oDocs visoScope) to a table-top camera (Zeiss VisucamNM/FA). SUBJECTS/METHODS: Healthy participants (n = 10, mean age ± SD = 21.0 ± 0.9 years) underwent fundus photography with five devices to assess success/failure rates of image acquisition. Participants with optic disc abnormalities (n = 8, mean age ± SD = 26.8 ± 15.9) and macular abnormalities (n = 10, mean age ± SD = 71.6 ± 15.4) underwent imaging with the top three scoring fundus cameras. Images were randomised and subsequently validated by ophthalmologists masked to the diagnoses and devices used. RESULTS: Image acquisition success rates (100%) were achieved in non-mydriatic and mydriatic settings for Zeiss, Remidio and Pictor, compared with lower success rates for iNview and oDocs. Image quality and gradeability were significantly higher for Zeiss, Remidio and Pictor (p < 0.0001) compared to iNview and oDocs. For cup:disc ratio estimates, similar levels of bias were seen for Zeiss (-0.09 ± SD:0.15), Remidio (-0.07 ± SD:0.14) and Pictor (-0.05 ± SD:0.16). Diagnostic sensitivities were highest for Zeiss (84.9%; 95% CI, 78.2-91.5%) followed by Pictor (78.1%; 95% CI, 66.6-89.5%) and Remidio (77.5%; 95% CI, 65.9-89.0%). CONCLUSIONS: Remidio and Pictor achieve comparable results to the Zeiss table-top camera. Both devices achieved similar scores in feasibility, image quality, image gradeability and diagnostic sensitivity. This suggests that these devices potentially offer a more cost-effective alternative in certain clinical scenarios.

Branch Retinal Vein Occlusion as a Rare Presentation of Antisynthetase Syndrome.

A 52-year-old woman developed branch retinal vein occlusion (BRVO) in her right eye, resulting in blurred vision with visual acuities of 6/9 and 6/6-2 in the affected and unaffected eye respectively (Snellen). The patient was successfully treated with a course of eight intravitreal aflibercept injections, improving binocular visual acuity to 6/6. During the course of her ocular management, she was admitted for acute dyspnoea secondary to interstitial lung disease (ILD). The patient was diagnosed with the antisynthetase syndrome (ASS), testing positive for PL-7 auto-antibodies. ASS may have a systemic association with BRVO; although ASS is a rare condition, it should be suspected and investigated in patients with risk factors, particularly if they present with symptoms of ILD. Early ocular intervention is associated with excellent visual outcomes, and prompt diagnosis and treatment of ASS may potentially reduce risks of further retinal vaso-occlusive episodes.

Redeployment of ophthalmologists in the United Kingdom during the Coronavirus Disease Pandemic.

BACKGROUND: During the current coronavirus (COVID-19) pandemic, some ophthalmologists across the United Kingdom (UK) have been redeployed to areas of need across the National Health Service (NHS). This survey was performed to assess aspects of this process including training & education, tasks expected, availability of personal protection equipment (PPE) used and the overall anxiety of ophthalmologists around their redeployment. METHOD: Online anonymous survey around the existing guidance on safe redeployment of secondary care NHS staff and PPE use by NHS England and Public Health England respectively. The survey was open to all ophthalmologists across the UK irrespective of their redeployment status. FINDINGS: 145 surveys were completed and returned during a 2-week period between 17th April 2020 and 1st May 2020, when 52% of ophthalmologists were redeployed. The majority of this group consisted of ophthalmologists in training (79%). 81% of those redeployed were assigned to areas of the hospital where patients with confirmed Coronavirus disease were being treated as inpatients. There was a statistically significant improvement in anxiety level following redeployment which was mainly attributed to the support received by staff within the redeployed area. 71% of the redeployed group were found to have sufficient PPE was provided for the area they worked in. INTERPRETATION: This is the first national survey performed on redeployment of ophthalmologists in the UK. The study showed that ophthalmologists across all grades were able to contribute in most aspects of patient care. Anxiety of redeployment was reduced by prior training and good support in the redeployment area.

Impact of COVID-19 pandemic and lockdown on eye emergencies.

BACKGROUND: To characterise and compare ocular pathologies presenting to an emergency eye department (EED) during the COVID-19 pandemic in 2020 against an equivalent period in 2019. METHODS: Electronic patient records of 852 patients in 2020 and 1818 patients in 2019, attending the EED at a tertiary eye centre (University Hospitals of Leicester, UK) were analysed. Data was extracted over a 31-day period during: (study period 1 (SP1)) COVID-19 pandemic lockdown in UK (24th March 2020-23rd April 2020) and (study period 2 (SP2)) the equivalent 2019 period (24th March 2019-23rd April 2019). RESULTS: A 53% reduction in EED attendance was noted during lockdown. The top three pathologies accounting for >30% of the caseload were trauma-related, keratitis and uveitis in SP1 in comparison to conjunctivitis, trauma-related and blepharitis in SP2. The overall number of retinal tears and retinal detachments (RD) were lower in SP1, the proportion of macula-off RD's (84.6%) was significantly (p = 0.0099) higher in SP1 (vs 42.9% in SP2). CONCLUSION: COVID-19 pandemic related lockdown has had a significant impact on the range of presenting conditions to the EED. Measures to stop spread of COVID-19 such as awareness of hand hygiene practices, social distancing measures and school closures could have an indirect role in reducing spread of infective conjunctivitis. The higher proportion of macula-off RD and lower number of retinal tears raises possibility of delayed presentation in these cases. Going forward, we anticipate additional pressures on EED and other subspecialty services due to complications and associated morbidity from delayed presentations.

A case and literature review of orbital microcystic adnexal carcinoma.

Microcystic adnexal carcinoma (MAC) is a very rare and locally aggressive sweat gland tumour. MAC has been well reported presenting as a periocular cutaneous lesion, rarely with subsequent direct orbital invasion and only once as a primary orbital lesion. Local recurrence is frequent after primary surgical excision and the role of adjuvant radiotherapy is ill-defined. We describe a case of orbital MAC treated successfully with radiotherapy after incomplete margin clearance post exenteration surgery and review the associated literature.

Papilloschisis: A Case Report.

We report a case of papilloschisis, where the schisis is noted within the optic nerve tissue with no associated disc pit. This has not been reported in the literature to the best of our knowledge.

Monotopic enzymes and lipid bilayers: a comparative study.

Monotopic proteins make up a class of membrane proteins that bind tightly to, but do not span, cell membranes. We examine and compare how two monotopic proteins, monoamine oxidase B (MAO-B) and cyclooxygenase-2 (COX-2), interact with a phospholipid bilayer using molecular dynamics simulations. Both enzymes form between three and seven hydrogen bonds with the bilayer in our simulations with basic side chains accounting for the majority of these interactions. By analyzing lipid order parameters, we show that, to a first approximation, COX-2 disrupts only the upper leaflet of the bilayer. In contrast, the top and bottom halves of the lipid tails surrounding MAO-B are more and less ordered, respectively, than in the absence of the protein. Finally, we identify which residues are important in binding individual phospholipids by counting the number and type of lipid atoms that come close to each amino acid residue. The existing models that explain how these proteins bind to bilayers were proposed following inspection of the X-ray crystallographic structures. Our results support these models and suggest that basic residues contribute significantly to the binding of these monotopic proteins to bilayers through the formation of hydrogen bonds with phospholipids.

Membrane protein dynamics and detergent interactions within a crystal: a simulation study of OmpA.

Molecular dynamics (MD) simulations are used to explore the dynamics of a membrane protein in its crystal environment. A 50-ns-duration simulation (at a temperature of 300 K) is performed for the crystallographic unit cell of the bacterial outer membrane protein OmpA. The unit cell contains four protein molecules, plus detergent molecules and water. An excellent correlation between simulated and experimental values of crystallographic B factors is observed. Effectively, 0.2 micros of protein trajectories are obtained, allowing a critical assessment of simulation quality. Some deficiency in conformational sampling is demonstrated, but averaging over multiple trajectories improves this limitation. The previously undescribed structure and dynamics of detergent molecules in a unit cell are reported here, providing insight into the interactions important in the formation and stabilization of the crystalline environment at room temperature. In particular, we show that at room temperature the detergent molecules form a dynamic, extended micellar structure spreading over adjacent OmpA monomers within the crystal.

Modeling and simulations of a bacterial outer membrane protein: OprF from Pseudomonas aeruginosa.

OprF is a major outer membrane protein from Pseudomonas aeruginosa, a homolog of OmpA from Escherichia coli. The N-terminal domains of both proteins have been demonstrated to form low conductance channels in lipid bilayers. Homology models, consisting of an eight-stranded beta-barrel, of the N-terminal domain OprF have been constructed based on the crystal structure of the corresponding domain from E. coli OmpA. OprF homology models have been evaluated via a set (6 x 10 ns) of simulations of the beta-barrel embedded within a solvated dimyristoyl-phosphatidylcholine (DMPC) bilayer. The conformational stability of the models is similar to that of the crystal structure of OmpA in comparable simulations. There is a degree of water penetration into the pore-like center of the OprF barrel. The presence of an acidic/basic (E8/K121) side-chain interaction within the OprF barrel may form a "gate" able to close/open a central pore. Lipid-protein interactions within the simulations were analyzed and revealed that aromatic side-chains (Trp, Tyr) of OprF interact with lipid headgroups. Overall, the behavior of the OprF model in simulations supports the suggestion that this molecule is comparable to OmpA. The simulations help to explain the mechanism of formation of low conductance pores within the outer membrane.

Anionic phospholipid interactions with the potassium channel KcsA: simulation studies.

Molecular dynamics (MD) simulations have been used to unmask details of specific interactions of anionic phospholipids with intersubunit binding sites on the surface of the bacterial potassium channel KcsA. Crystallographic data on a diacyl glycerol fragment at this site were used to model phosphatidylethanolamine (PE), or phosphatidylglycerol (PG), or phosphatidic acid (PA) at the intersubunit binding sites. Each of these models of a KcsA-lipid complex was embedded in phosphatidyl choline bilayer and explored in a 20 ns MD simulation. H-bond analysis revealed that in terms of lipid-protein interactions PA > PG >> PE and revealed how anionic lipids (PG and PA) bind to a site provided by two key arginine residues (R(64) and R(89)) at the interface between adjacent subunits. A 27 ns simulation was performed in which KcsA (without any lipids initially modeled at the R(64)/R(89) sites) was embedded in a PE/PG bilayer. There was a progressive specific increase over the course of the simulation in the number of H-bonds of PG with KcsA. Furthermore, two specific PG binding events at R(64)/R(89) sites were observed. The phosphate oxygen atoms of bound PG formed H-bonds to the guanidinium group of R(89), whereas the terminal glycerol H-bonded to R(64). Overall, this study suggests that simulations can help identify and characterize sites for specific lipid interactions on a membrane protein surface.

Molecular dynamics simulations of GlpF in a micelle vs in a bilayer: conformational dynamics of a membrane protein as a function of environment.

Octyl glucoside (OG) is a detergent widely employed in structural and functional studies of membrane proteins. To better understand the nature of protein-OG interactions, molecular dynamics simulations (duration 10 ns) have been used to explore an alpha-helical membrane protein, GlpF, in OG micelles and in DMPC bilayers. Greater conformational drift of the extramembraneous protein loops, from the initial X-ray structure, is seen for the GlpF-OG simulations than for the GlpF-DMPC simulation. The mobility of the transmembrane alpha-helices is approximately 1.3x higher in the GlpF-OG than the GlpF-DMPC simulations. The detergent is seen to form an irregular torus around the protein. The presence of the protein leads to a small perturbation in the behavior of the alkyl chains in the OG micelle, namely an approximately 15% increase in the trans-gauche(-)-gauche(+) transition time. Aromatic side chains (Trp, Tyr) and basic side chains (Arg, Lys) play an important role in both protein-detergent (OG) and protein-lipid (DMPC) interactions.

MD simulations of spontaneous membrane protein/detergent micelle formation.

The in vitro study of membrane proteins for the purpose of physicochemical analysis or structure determination often relies upon successful reconstitution into detergent micelles. Moreover, a number of biological processes such as membrane protein folding and transport rely on lipid interactions which may resemble the micellar environment. Little is known about the structures of these micelles or the processes which lead to their formation. We therefore present two 50 ns all-atom molecular dynamics simulations of spontaneous dodecylphosphocholine micelle formation around representatives of the two major families of membrane proteins, a small beta-barrel protein, OmpA, and a model alpha-helical protein, glycophorin A. Despite differences in protein architecture, we highlight common mechanistic pathways in micelle formation, which are consistent with experimental studies. We characterize the exponential kinetics of detergent-protein adsorption and suggest a simple model which may explain the aggregation process. We also compare the results with 25 and 50 ns simulations of preformed micelles containing the same proteins. We confirm that the end structures of the self-assembled micelles are similar to those from their preformed counterparts, with each micelle presenting a bilayerlike environment to the enclosed protein.

Lipid-protein interactions of integral membrane proteins: a comparative simulation study.

The interactions between membrane proteins and their lipid bilayer environment play important roles in the stability and function of such proteins. Extended (15-20 ns) molecular dynamics simulations have been used to explore the interactions of two membrane proteins with phosphatidylcholine bilayers. One protein (KcsA) is an alpha-helix bundle and embedded in a palmitoyl oleoyl phosphatidylcholine bilayer; the other (OmpA) is a beta-barrel outer-membrane protein and is in a dimyristoyl phosphatidylcholine bilayer. The simulations enable analysis in detail of a number of aspects of lipid-protein interactions. In particular, the interactions of aromatic amphipathic side chains (i.e., Trp, Tyr) with lipid headgroups, and "snorkeling" interactions of basic side chains (i.e., Lys, Arg) with phosphate groups are explored. Analysis of the number of contacts and of H-bonds reveal fluctuations on an approximately 1- to 5-ns timescale. There are two clear bands of interacting residues on the surface of KcsA, whereas there are three such bands on OmpA. A large number of Arg-phosphate interactions are seen for KcsA; for OmpA, the number of basic-phosphate interactions is smaller and shows more marked fluctuations with respect to time. Both classes of interaction occur in clearly defined interfacial regions of width approximately 1 nm. Analysis of lateral diffusion of lipid molecules reveals that "boundary" lipid molecules diffuse at about half the rate of bulk lipid. Overall, these simulations present a dynamic picture of lipid-protein interactions: there are a number of more specific interactions but even these fluctuate on an approximately 1- to 5-ns timescale.

Nucleotide-dependent conformational changes in HisP: molecular dynamics simulations of an ABC transporter nucleotide-binding domain.

ATP-binding cassette (ABC) transporters mediate the movement of molecules across cell membranes in both prokaryotes and eukaryotes. In ABC transporters, solute translocation occurs after ATP is either bound or hydrolyzed at the intracellular nucleotide-binding domains (NBDs). Molecular dynamics (MD) simulations have been employed to study the interactions of nucleotide with NBD. The results of extended (approximately 20 ns) MD simulations of HisP (total simulation time approximately 80 ns), the NBD of the histidine transporter HisQMP2J from Salmonella typhimurium, are presented. Analysis of the MD trajectories reveals conformational changes within HisP that are dependent on the presence of ATP in the binding pocket of the protein, and are sensitive to the presence/absence of Mg ions bound to the ATP. These changes are predominantly confined to the alpha-helical subdomain of HisP. Specifically there is a rotation of three alpha-helices within the subdomain, and a movement of the signature sequence toward the bound nucleotide. In addition, there is considerable conformational flexibility in a conserved glutamine-containing loop, which is situated at the interface between the alpha-helical subdomain and the F1-like subdomain. These results support the mechanism for ATP-induced conformational transitions derived from the crystal structures of other NBDs.