Ophthalmology
Recent Submissions
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Care of the eye during anaesthesia and intensive carePerioperative eye injuries and blindness are rare but important complications of anaesthesia. The three causes of postoperative blindness are ischaemic optic neuropathy, central retinal artery thrombosis (these can exist in tandem and have been described as ischaemic oculopathies) and cortical blindness. This review aims to improve anaesthetists' knowledge of orbital anatomy, ocular physiology and the mechanisms of perioperative eye injuries to help reduce their occurrence.
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Efficacy and timing of adjunctive therapy in the anti-VEGF treatment regimen for macular oedema in retinal vein occlusion : 12-month real-world resultPurpose Various combination treatment regimens have been tried to improve the short-term efficacy of intravitreal monotherapy for the treatment of macular oedema (MO) secondary to retinal vein occlusion (RVO). Our study introduces the RandOL protocol (Ranibizumab and Ozurdex with Laser photocoagulation) of initial anti-VEGF therapy, controlling recurrent non-ischaemic MO with an intravitreal steroid and applying laser therapy to non-perfused retina. We describe our 12-month follow-up experience on timing for adjunctive therapy and real-world effectiveness and safety data. Methods A retrospective analysis was carried out on 66 consecutive treatment-naive RVO patients with MO who received our RandOL treatment regimen. Baseline visual acuity (VA) and central retinal thickness (CRT) were compared with 12-month result. Results At 12 months, 77% had significant VA improvement, 52% had ≥3-line improvement, and 15% were worse. Significant improvements in CRT were observed in 97% (baseline median CRT=531 μm (IQR 435-622) reduced to 245 μm (IQR 221-351, P<0.001) at 12 months); 76% achieved a dry fovea at 1 year. Mean number of total injections required was 5.5 (range 2-11) and 6% required ≥9 injections in 1 year. Although 70% received additional Ozurdex, 82% received ≥1 sessions of laser therapy. The BRVO subgroup achieved better VA and CRT improvement at 1 year, but small numbers limit definitive statistical conclusions. Conclusions Our real-world results using a combination treatment protocol for RVO-related MO achieved similar desirable anatomical and visual outcomes as with a single-agent therapy with less intravitreal re-treatment rates at first year. Randomised controlled studies are needed to evaluate the role of laser and the ideal timing of combination therapy.
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Xen45 Gel Stent implant: patient reported outcomesOur aim was to report quality of life (QOL) outcomes following Xen45 Gel Stent implantation surgery in patients suffering with primary open angle glaucoma (POAG). A retrospective analysis was performed on all patients who had Xen45 implantation surgery during a 2-year period (Jun, 2016-Apr, 2018). Of 52 consecutive patients were included with a total of 58 eyes being operated on. QOL was compared both pre-operatively and 6 weeks post-operatively using the GQL-15 questionnaire. There was an overall improvement in GQL-15 summary scores for our patient group. All item scores showed either no change or some degree of improvement. The Xen45 Gel Stent Implant is a promising new intervention which has shown improved QOL scores in our patient group. Further, higher power studies are now needed to compare the Xen45 to trabeculectomy (TE), which is currently the gold standard. Keywords: Xen45 Gel Stent implant; glaucoma; minimally invasive glaucoma surgery.
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The role of optical coherence tomography in therapeutics and conditions, which primarily have systemic manifestations: a narrative reviewOptical coherence tomography is designed to evaluate in vivo qualitative and quantitative changes of the anterior segment, optic nerve and the retina. Initial applications of this technology were confined mainly to ophthalmic diseases. However recently, numerous studies have evaluated its use in systemic conditions and in therapeutics where, optic nerve and retinal architecture can be assessed to monitor progression of systemic conditions and its response to treatment. This is a narrative review aimed at evaluating the debate surrounding the role of spectral domain optical coherence tomography, in systemic conditions where optic nerve affection can be measured and be used in the diagnosis, monitoring and assessment of treatment effect as a non-invasive, quick, novel technique. Keywords: nutrition; optical coherence tomography; retinal nerve fibre layer; systemic disease; therapeutics.
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Action on neovascular age-related macular degeneration (nAMD): recommendations for management and service provision in the UK hospital eye serviceThis report by a group of UK retina specialists and health professionals considers best practice recommendations for the management of sight-threatening neovascular age-related macular degeneration (nAMD), based on collective experience and expertise in routine clinical practice. The authors provide an update for ophthalmologists, allied healthcare professionals and commissioners on practice principles for optimal patient care and service provision standards. Refinement of care pathways for nAMD has improved access to intravitreal anti-vascular endothelial growth factor therapy but there are still variations in care and reported outcomes between clinic centres. Innovative organisational models of service provision allow providers to better match capacity with increasing demand. The authors review the recent NICE guideline for diagnosis and management of AMD, considerations for switching therapies and stopping treatment and need for regular monitoring of non-affected fellow eyes in patients with unilateral nAMD. Actions for delivery of high-quality care and to improve long-term patient outcomes are discussed. Local pathways need to detail nAMD target time to treat, maintenance of review intervals to ensure proactive treatment regimens are delivered on time and appropriate discharge for patients deemed low risk or no longer benefiting from treatment. Actual visual acuity outcomes achieved and maintenance of the level of vision when disease stability is achieved are considered good measures for judging the quality of care in the treatment of patients with nAMD. Robust community referral pathways must be in place for suspected reactivation of choroidal neovascularisation and rapid referral for second eye involvement. Practical considerations for intravitreal injection therapy are outlined.
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The Clinical Application of Polarization Pattern PerceptionPurpose: Determine the repeatability of and optimum stimulus parameters for testing polarization pattern perception in a real-world clinical population, and assess the ability of polarization perception to distinguish normal from abnormal eyes. Methods: Polarization perception was evaluated in staff and patients attending ophthalmology clinics at Warwick Hospital, UK. A series of visual stimuli were presented in pseudorandom order using a liquid-crystal-display-based polarization pattern generator. Stimuli included geometric patterns, gratings, checkerboards, and optotypes. Participants had one or both eyes diagnosed as normal or abnormal following ophthalmic examination, optical coherence tomography, and measures of visual acuity. Measurement scores were assigned to the eye(s) of each participant depending on the total number of stimuli perceived or identified. Results: Stimuli covered the range of spatial scales resolvable within polarization perception by normal and abnormal eyes. Different stimuli had different saliencies. For each stimulus type, polarization perception in the abnormal group was significantly reduced compared with normal eyes (P < 0.001). Relative stimulus salience was broadly similar for normal-eye and abnormal-eye viewing groups, being greatest for radially symmetric patterns and least for optotypes. Checkerboard pattern salience had an inverse logarithmic relationship with check fundamental spatial frequency. A devised metric covering the dynamic range of polarization perception was repeatable, and the score derived from the metric was reduced in the abnormal group compared with the normal group (P < 0.001). Conclusions: Clinically useful metrics of polarization perception distinguish between normal and abnormal eyes. Translational relevance: Perception of spatial patterns formed of non-uniform polarization fields has potential as a quantitative clinical diagnostic measurement. Keywords: light polarization; macular pigment; vision; vision testing; visual dysfunction.
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Polarization perception in humans: on the origin of and relationship between Maxwell's spot and Haidinger's brushesUnder specific conditions of illumination and polarization, differential absorption of light by macular pigments is perceived as the entoptic phenomena of Maxwell's spot (MS) or Haidinger's brushes (HB). To simulate MS and HB, an existing computational model of polarization-dependent properties of the human macula was extended by incorporating neuronal adaptation to stabilized retinal images. The model predicted that polarized light modifies the appearance of MS leading to the perception of a novel phenomenon. The model also predicted a correlation between the observed diameters of MS and HB. Predictions were tested psychophysically in human observers, whose measured differences in the diameters of each entoptic phenomenon generated with depolarized and linearly polarized light were consistent with the model simulations. These findings support a common origin of each phenomenon, and are relevant to the clinical use of polarization stimuli in detecting and monitoring human eye disorders, including macular degeneration. We conclude: (i) MS and HB both result from differential light absorption through a radial diattenuator, compatible with the arrangement of macular pigments in Henle fibres; (ii) the morphology of MS is dependent on the degree of linear polarization; (iii) perceptual differences between MS and HB result from different states of neural adaptation.
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The electrophysiological response to polarization-modulated patterned visual stimuliRecent reports indicate that the subjective ability of humans to discriminate between polarization E-vector orientations approaches that of many invertebrates. Here, we show that polarization-modulated patterned stimuli generate an objectively recordable electrophysiological response in humans with normal vision. We investigated visual evoked potential (VEP) and electroretinographic (ERG) responses to checkerboard patterns defined solely by their polarization E-vector orientation alternating between ± 45°. Correcting for multiple comparisons, paired-samples t-tests were conducted to assess the significance of post-stimulus deflections from baseline measures of noise. Using standard check pattern sizes for clinical electrophysiology, and a pattern-reversal protocol, participants showed a VEP response to polarization-modulated patterns (PolVEP) with a prominent and consistent positive component near 150 ms (p < 0.01), followed by more variable negative components near 200 ms and 300 ms. The effect was unrecordable with visible wavelengths >550 nm. Further, pseudo-depolarization negated the responses, while control studies provided confirmatory evidence that the PolVEP response was not the product of luminance artefacts. Polarization-modulated patterns did not elicit a recordable ERG response. The possible origins of the PolVEP signals, and the absence of recordable ERG signals, are discussed. We conclude that evoked cortical responses to polarization-modulated patterns provide an objective measure of foveal function, suitable for both humans and non-human primates with equivalent macular anatomy.
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The effect of age-related macular degeneration on polarization pattern perceptionPurpose: The purpose of this study was to determine if a battery of polarization-modulated stimuli, quantified as a single metric, is effective in identifying macular disease in the presence/absence of cataract or pseudophakia. Methods: Using a modified liquid crystal display, polarization pattern perception (PPP) for a formulated battery of geometric and logMAR stimuli was evaluated in participants that had either no eye pathology (healthy participants) or were grouped according to the presence of cataract, pseudophakia, and/or age-related macular degeneration (AMD). PPP was quantified as response frequencies to individual stimuli, and as a novel monocular polarization sensitivity score (Ps) based on perception of the stimulus battery set. Results: Stimulus response frequencies were pattern-dependent and, compared with healthy participants, reduced for cataract and AMD groups but not for subjects with pseudophakia. Compared with healthy eyes (n = 47, median Ps = 17), Ps was significantly reduced by AMD (n = 59, median Ps = 1, P < 0.001) and, to a lesser extent, by cataracts (n = 80, median Ps = 6, P < 0.001). There was no significant difference between Ps for healthy and pseudophakic eyes (n = 47, median Ps = 13, P = 0.323). There was no significant correlation between Ps and logMAR visual acuity. Conclusions: In the absence of significant cataract, or in pseudophakia, a set of polarization-modulated visual stimuli, quantified as the Ps score, distinguishes AMD from healthy maculae. Translational relevance: Perception of polarization-modulated stimuli, previously shown to be macula-dependent in a laboratory setting, is effective as a test of macular function in health and disease in a clinic setting.
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Seeing polarization of light with the naked eyeMany readers may know that scores of animal species sense the polarization of light for purposes including navigation, predation, and communication1. It is commonly thought that humans lack any sensitivity to polarization of light (e.g., Morehouse2). We hope to convince you otherwise by describing three examples where humans can detect polarization of light with the naked eye, by showing you how to see it yourself, and by describing its uses.
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Bariatric surgery-what the ophthalmologist needs to knowThe incidence of bariatric surgery is increasing due to obesity being one of our top public health challenges. As such, bariatric-related ophthalmic changes are a potentially new clinical area of knowledge, with increasing published evidence on post-bariatric complications experienced by patients and identified by clinicians. We reviewed the available literature and summarised the different complications and potential recommendations. A search strategy was conducted with PubMed, Cochrane, Medline, Embase, Allied and Complementary Medicine and DH-DATA databases to look for papers answering our research question: "What are the ophthalmological complications for patients after bariatric surgery?". Our search gave a total of 59 relevant papers. Bariatric surgery, particularly subtypes that cause direct bypass of nutrients from the stomach, lead to nutritional deficiencies. Vitamin A, crucial for proper functioning of body systems and specialised cells, manifests ophthalmologically as corneal ulceration, nyctalopia, conjunctival xerosis and more. Thiamine levels are also depleted, leading to Wernicke's Encephalopathy. Pre-existing diabetic retinopathy is also noted to worsen sub acutely, although evidence is conflicting. Patients undergoing surgery to treat idiopathic intracranial hypertension would have reduced IOP and resolving papilloedema. Other comorbidities of obesity like HBA1C levels, obstructive sleep apnoea, and metabolic syndrome also resolve post-surgery. History taking remains the cornerstone of medical practice. From the evidence, we suggest consideration of pre-surgery screening for ophthalmic pathology and post-operative monitoring of disease progression. Real-world data needs to continuously be analysed to create definitive management pathways that can help clinicians recognise ophthalmic complications early, improving patient outcomes.
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Three-dimensional printing in ophthalmology and eye care: current applications and future developmentsThree-dimensional (3D) printing uses a process of adding material in a layer-by-layer fashion to form the end product. This technology is advancing rapidly and is being increasingly utilized in the medical field as it becomes more accessible and cost-effective. It has an increasingly important role in ophthalmology and eyecare as its current and potential applications are extensive and slowly evolving. Three-dimensional printing represents an important method of manufacturing customized products such as orbital implants, ocular prostheses, ophthalmic models, surgical instruments, spectacles and other gadgets. Surgical planning, simulation, training and teaching have all benefitted from this technology. Advances in bioprinting seem to be the future direction of 3D printing with possibilities of printing out viable ocular tissues such as corneas and retinas in the future. It is expected that more ophthalmologists and other clinicians will use this technology in the near future.
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To evaluate the efficacy of diagnostic periocular punch biopsy: using a 4-mm dermatology punch.Purpose: The dermatological punch biopsy is a minimally invasive procedure that provides conclusive diagnosis when managing periocular lesions. It aids with establishing histological diagnosis and subtype thereby facilitating management planning and eliminates the risk of unnecessary tissue sacrifice. The present literature provides limited evidence evaluating the value of punch biopsy in diagnosing periocular lesions. Methods: A retrospective case note analysis of 400 consecutive 4-mm periocular punch biopsies performed between 2005 and 2016, from 353 patients was undertaken at a single institution. Three hundred fifty-nine lesions had an initial definite clinical diagnosis of malignancy (group A) and the remaining 41 lesions had an uncertain clinical diagnosis with enough suspicion to merit a biopsy (group B). Results: In group A, 75.5% (n = 271) of the biopsies verified the clinical diagnosis of malignancy and 24.5% (n = 88) were benign. In group B, 70.7% (n = 29) of the lesions were benign and 29.3% (n = 12) were malignant and were subsequently treated as group A. Only 4, group A biopsies, which underwent formal excision, did not initially diagnose a malignancy (punch biopsy was repeated) providing a sensitivity of 98.6% and a specificity of 100%. One hundred seventeen were found to be benign avoiding unnecessary tissue sacrifice in 29.25% of cases. Conclusion: Our study provides the largest sample size in the literature that evaluates a 4-mm diagnostic periocular punch biopsy in managing eyelid lesions. In 29.5% of punch biopsies, unnecessary tissue sacrifice was avoided as they were histologically benign. The authors found that punch biopsies for lesions <7 mm carry a risk of inadvertent excision of lesion.
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United Kingdom database study of intravitreal dexamethasone implant (Ozurdex) for macular edema related to retinal vein occlusionPurpose: To study the treatment patterns, visual outcomes and safety profile of intravitreal dexamethasone implant (IDI) used for the treatment of macular edema secondary to retinal vein occlusion. Methods: Up to 2 years of routinely collected anonymized data within electronic medical record systems were remotely extracted from 16 centers. The outcome measures include visual outcome, number of injections, and safety measures, including the rate of intraocular pressure (IOP) rise, frequency of IOP-lowering medication usage, and cataract surgery rates. Results: The study included 688 eyes (44.4%) with central retinal vein occlusion and 862 eyes (55.6%) with branch retinal vein occlusion; 1,250 eyes (80.6%) were treatment naive and 28% (275/989) had high IOP or were on IOP-lowering medications before IDI use. It was found that 31% (476) of eyes received two injections, and 11.7% (182) and 3.7% (58) of eyes received three and four injections, respectively. The mean baseline Snellen visual acuity improved from 20/125 to 20/40 after the first injection. The probability of cataract surgery was 15% at 24 months. The proportion of eyes with ≥10 mmHg change from baseline was higher in phakic (14.2%) compared with pseudophakic eyes (5.4%, P = 0.004). Three eyes required IOP filtering surgery (0.2%). Conclusion: The visual results of IDI in eyes with macular edema secondary to retinal vein occlusion in the real world are comparable to those of clinical trial setting. Increased IOP in eyes with preexisting ocular hypertension or glaucoma can be controlled with additional medical treatment. Intraocular pressure rise with IDI may be more frequent in phakic than in pseudophakic eyes.