Identification of candidate protective variants for common diseases and evaluation of their protective potential.

BACKGROUND: Human polymorphisms with derived alleles that are protective against disease may provide powerful translational opportunities. Here we report a method to identify such candidate polymorphisms and apply it to common non-synonymous SNPs (nsSNPs) associated with common diseases. Our study also sought to establish which of the identified protective nsSNPs show evidence of positive selection, taking this as indirect evidence that the protective variant has a beneficial effect on phenotype. Further, we performed an analysis to quantify the predicted effect of each protective variant on protein function/structure. RESULTS: An initial analysis of eight SNPs previously identified as associated with age-related macular degeneration (AMD), revealed that two of them have a derived allele that is protective against developing the disease. One is in the complement component 2 gene (C2; E318D) and the other is in the complement factor B gene (CFB; R32Q). Then, combining genomewide ancestral allele information with known common disease-associated nsSNPs from the GWAS catalog, we found 32 additional SNPs which have a derived allele that is disease protective. Out of the total 34 identified candidate protective variants (CPVs), we found that 30 show stronger evidence of positive selection than the protective variant in lipoprotein lipase (LPL; S447X), which has already been translated into gene therapy. Furthermore, 11 of these CPVs have a higher probability of affecting protein structure than the lipoprotein lipase protective variant (LPL; S447X). CONCLUSIONS: We identify 34 CPVs from the human genome. Diseases they confer protection against include, but are not limited to, type 2 diabetes, inflammatory bowel disease, age-related macular degeneration, multiple sclerosis and rheumatoid arthritis. We propose that those 30 CPVs with evidence of stronger positive selection than the LPL protective variant, may be considered as priority candidates for therapeutic approaches. The next step towards translation will require testing the hypotheses generated by our analyses, specifically whether the CPV arose from a gain-of-function or a loss-of-function mutation.

Novel metrics for evaluating decision making in a 'Treat and Extend' regimen for neovascular age related macular degeneration.

BACKGROUND: The primary aim was to investigate outcome of the decision making on duration of injection intervals between injection visits over the first 2 years of a treat and extend regimen. METHOD: Consecutive patients receiving Aflibercept for treatment naïve neovascular age-related macular degeneration between 01.01.2016 and 15.07.2017 were identified from our departmental register. Retrospective data collected on all visits over 24 months were classified into three groups: (A) Without Interval Decision Events (IDE)" Injection only" (B) IDE resulting in injection intervals of <5 weeks and (C) IDE resulting in intervals of >5 weeks. The primary outcome was number of successful IDE relative to the total visits in Group C. Successful decision making was defined as absence of worsening of visual acuity (>5 L) or central retinal thickness (>50 microns) at the subsequent visit. Secondary visual and anatomical outcomes at 24 months were also evaluated. RESULTS: Data from 56 eyes of 50 patients were included in the study. Visual acuity improved by +7.11 L at 24 months. Forty one patients with unilateral therapy made 721 visits: 280 visits (38.8%) were group A; 164 visits (22.8%) were group B and 277 visits (38.4%) were group C. Average interval in Group C was 8.9 weeks (range 5-15). The success rate of extension was 95.31% (264/277 visits). CONCLUSION: These metrics for evaluating the decision making aspect of disease activity monitoring may be useful for monitoring performance and have given us a more realistic view and expectations of what can be achieved using this regime to optimise the timing of injections.

Recommendations by a UK expert panel on an aflibercept treat-and-extend pathway for the treatment of neovascular age-related macular degeneration.

OBJECTIVES: This report aims to provide clear recommendations and practical guidance from a panel of UK retinal experts on an aflibercept treat-and-extend (T&E) pathway that can be implemented in clinical practice. These recommendations may help service providers across the NHS intending to implement a T&E approach, with the aim of effectively addressing the capacity and resource issues putting strain on UK neovascular age-related macular degeneration (nAMD) services while promoting patients' best interests throughout. METHODS: Two structured roundtable meetings of retinal specialists were held in London, UK on 7 December 2018 and 1 March 2019. These meetings were organised and funded by Bayer. RESULTS: The panel provided recommendations for an aflibercept T&E pathway and developed specific criteria based on visual acuity, retinal morphology and optical coherence tomography imaging to guide reduction, maintenance and extension of injection intervals. They also discussed the extension of treatment intervals by 2- or 4-week adjustments to a maximum treatment interval of 16 weeks, the management of retinal fluid and the stopping of treatment. CONCLUSIONS: The long-term benefits of implementing a T&E pathway may include superior visual outcomes compared with a pro re nata (PRN; as needed) protocol, and a lower treatment burden compared with a fixed protocol, which is likely to improve service capacity. Furthermore, the predictable nature of a T&E approach compared with a PRN service may aid capacity planning for the future nAMD treatment demand.

No sutures corneal grafting--a novel use of overlay sutures and fibrin glue in Deep Anterior Lamellar Keratoplasty.

PURPOSE: To describe a case where Deep Anterior Lamellar Keratoplasty (DLK) was performed using overlay sutures and fibrin glue alone, without the need to directly suture the corneal button. METHODS: Deep Anterior Lamellar Keratoplasty was performed using a modified Melles technique on a 21-year-old patient who had stromal scarring secondary to severe infective keratitis. Overlay sutures and fibrin glue were used to secure the donor button and then a bandage contact lens was inserted. No sutures were required to directly suture the donor button to host tissue. All securing sutures were removed 4 weeks after the surgery. Six months post surgery, the graft was clear and the patient rehabilitated by wearing acceptable astigmatic spectacle correction. RESULTS: The patients visual acuity in the affected eye was 6/12 wearing a spectacle prescription of -0.25/-3.25x160. CONCLUSION: The use of overlay sutures and fibrin glue in DLK is a time efficient and effective technique. We propose that this technique may be used routinely in cases where donor corneal button appears to fit well in the stromal bed at the time of surgery, that is, where there is no disparity in the thickness of the donor button compared to the host bed.

Resource Use and Real-World Outcomes for Ranibizumab Treat and Extend for Neovascular Age-Related Macular Degeneration in the UK: Interim Results from TERRA.

INTRODUCTION: Ranibizumab is an inhibitor of vascular endothelial growth factor-A (anti-VEGF) approved for the treatment of neovascular age-related macular degeneration (nAMD). The treat and extend (T&E) regimen can potentially reduce the burden of clinic visits compared with a pro re nata (PRN) regimen. Retrospective, interim analyses of clinical effectiveness, treatment and resource use patterns were conducted using real-world data in England and Wales from the TERRA study. METHODS: Two cohorts, those switching from a PRN to a T&E regimen ('prior PRN') and those initiating ranibizumab on the T&E regimen as their first anti-VEGF therapy ('anti-VEGF-naïve') were enrolled in TERRA. Retrospective clinical assessments were gathered from medical records, while resource use patterns were collected via an operating cost questionnaire completed by each study site. RESULTS: At the interim analysis cut-off date (15 November 2016), 11 sites had enrolled 145 patients (prior PRN: n = 110; anti-VEGF-naïve: n = 35). Mean change from baseline (date of first injection) in visual acuity and central subfield retinal thickness to 12 months was +7.6 Early Treatment Diabetic Retinopathy Study letters [95% confidence interval (CI) 2.8, 12.4; p = 0.003; n = 27] and -67.7 µm (95% CI -106.5, -28.9; p = 0.001, n = 29), respectively, in the anti-VEGF-naïve cohort. Most T&E clinics were run as one-stop services (same-day monitoring and injection), whereas 4/10 PRN clinics were run as two-stop services (monitoring and injection on different days). In general, one-stop clinics used less staff resources and were likely to be shorter in duration for healthcare providers than the cumulative time spent for two-stop clinics. CONCLUSION: This is the first real-world observational study conducted in England and Wales demonstrating the effectiveness of the ranibizumab T&E regimen in anti-VEGF-naïve patients. T&E is compatible with one-stop clinic services, which these real-world data suggest to be less resource intensive than two-stop clinic services, possibly providing a dosing regimen beneficial to both patients and resource burden in UK clinical practice. FUNDING: Novartis Pharmaceuticals UK Limited.

Avastin and Lucentis: what do patients know? A prospective questionnaire survey.

OBJECTIVES: To assess patients' knowledge of their drug therapy for neovascular macular degeneration and to identify which aspects of the drug they considered most important if given the option of switching to an alternative drug. DESIGN: Prospective questionnaire survey. SETTING: Wolverhampton, England. PARTICIPANTS: A total of 126 patients attending our hospital service for intravitreal ranibizumab therapy for neovascular macular degeneration. MAIN OUTCOME MEASURES: Using a questionnaire, patients were asked questions pertaining to aspects of drug therapy in neovascular macular degeneration. Fields covered included drug names, knowledge of alternative drugs, cost of drugs and their views on switching to another drug. RESULTS: Eighty (63.5%) had heard of Lucentis (ranibizumab) and 31 (24.6%) were aware of Avastin (bevacizumab). Of the latter 31 patients, 20 did not have a preference between Avastin and Lucentis. These patients felt that the factors they would consider important for them to consider switching were effectiveness (10, 50%), specialist recommendation (8, 40%), safety (2, 10%) and cost (0). CONCLUSIONS: Introducing a cheaper, off-label alternative in the therapy of macular degeneration in the presence of a licensed option has been extensively debated. Many patients have no knowledge of this controversial issue but it is likely that efficacy and recommendation by clinicians are more important than cost to patients who may consider switching to the off-label Avastin.

Evaluation of patients' experiences at different stages of the intravitreal injection procedure - what can be improved?

INTRODUCTION: Intravitreal injection of ranibizumab has become one of the most commonly performed ophthalmic procedures. It is timely to conduct an evaluation of the injection procedure from the patient's perspective so as to determine ways to improve patient experience. The purpose of this study was to quantitatively describe patients' experiences of the different stages of the intravitreal injection procedure and provide suggestions for improvement. METHOD: Following intravitreal injection, patients were administered a questionnaire to score the distress felt for each of ten parts of the whole injection process from the initial waiting to the final instillation of topical antibiotic at the end. A score of higher than 4 was regarded as significantly unpleasant. The proportion of scores above 4 for each step was used to evaluate the relative distress experienced by patients for the different parts of the procedure. RESULTS: A total of 42 patients were surveyed. The step with the highest percentage of patients scoring more than 4 was the injection step (19%). However, cumulatively, the steps relating to the application of the drape, the speculum, and the removal of drape accounted for 53% of scores greater than 4. CONCLUSION: There is considerable variation in how patients tolerate different stages of the injection procedure. The needle entry was the most unpleasant step followed by the draping steps cumulatively. Use of subconjunctival anesthesia, a perforated drape, and alternative lid exclusion devices may help to improve the patient's tolerability of the procedure and experience.

Five-year retrospective review of guideline-based management of fungal endophthalmitis.

PURPOSE: Guidelines were introduced in 2000 at the Bristol Eye Hospital (BEH) for the management of fungal endophthalmitis. A 5-year retrospective audit re-evaluated the guidelines and monitored the management of this rare condition. Clinical effectiveness and management costs were considered in light of visual outcome. METHODS: Cases were identified through a 5-year retrospective review of theatre logbooks, Patient Administration System coded admissions with primary diagnosis of purulent endophthalmitis and pharmacy logbooks of patients receiving antifungal therapy. Data correlation and review of patient management were carried out in light of the findings. RESULTS: Twenty-three cases were included, based on clinical disease and/or positive smears or cultures. Age range was 13-74 years, with a male : female ratio of 16 : 7 and right eye : left eye ratio of 14 : 9. Risk factors for fungal endophthalmitis included septicaemia caused by intravenous drug use (78%), presence of indwelling lines (9%), postocular surgery (9%) and post-trauma (4%). Guidelines were rigidly followed in 56% of cases, with improved visual acuity in 9/13 patients compared to 4/10 where management deviated from guidelines. Deviation from guidelines occurred with incomplete use of the recommended drug regimen for the disease severity or use of drugs that were alternative to the suggested guidelines. Treatment was initiated on clinical judgement in 91% of cases and laboratory diagnosis in 9%. CONCLUSION: The BEH guidelines provided a useful reference when managing this uncommon condition. Voriconazole, a newer broad-spectrum agent with good ocular penetration (used in 9%), has been added to the revised guidelines. Monitoring rare conditions over prolonged time frames supports evidence-based medicine

Blood storage at 4 degrees C-factors involved in DNA yield and quality.

BACKGROUND: Whole blood provides one of the most common sources of both high-quality DNA and high-quantity DNA for molecular biological purposes. Typically, blood storage at 4 degrees C is short term, which ranges from a few days to a few weeks. However, long-term storage usually involves blood being frozen, with a resultant loss in DNA yield. The authors examined the effects of long-term storage at 4 degrees C. METHODS: Duplicate blood samples were collected from 301 participants (aged 20-98 years) enrolled as part of ongoing studies. Samples were stored at 4 degrees C for between 11 days and 922 days, and DNA was subsequently extracted using a phenol/chloroform procedure. RESULTS: A negative correlation of the number of storage days existed at 4 degrees C with DNA yield. The main determinant on DNA yield was the age of the participant in the study, with older persons having a lower DNA yield. CONCLUSIONS: Long-term storage of blood at 4 degrees C does have a detrimental effect on DNA yield, but this effect seemed less significant than the age of a person. The impact of age of a person or storage time has a minimal impact on DNA quality. Therefore, storage of blood at 4 degrees C offers an acceptable alternative to frozen storage.

The effects of aspirin and warfarin therapy on haemorrhage in vitreoretinal surgery.

BACKGROUND: No substantial recommendations exist regarding the management of anticoagulant drugs prior to ocular surgery. Stopping anticoagulation can cause fatal emboli, but sight-threatening bleeds may occur if anticoagulation is continued. We examined the effects of anticoagulation on vitreoretinal surgery. METHODS: Clinical details were prospectively entered on a database. The anticoagulant status of 541 consecutive patients undergoing vitreoretinal surgery was recorded. RESULTS: Sixty patients in the study were taking aspirin and seven were taking warfarin. There were 11 cases of choroidal haemorrhage, one of which involved a warfarin user. Of 325 retinal detachment repairs, 21 (6.5%) had preoperative vitreous haemorrhages. Two of these patients were on aspirin and two were on warfarin. Sixty-six vitrectomies were performed for diabetic vitreous haemorrhages, of which nine re-bled postoperatively. One of these patients was taking warfarin. The association of warfarin with bleeding was statistically significant (relative risk 6.185). CONCLUSION: Anticoagulation had no effect on the number of significant perioperative (choroidal) haemorrhages. Aspirin had little effect on bleeding during vitreoretinal surgery. Warfarin, however, was associated with bleeding complications. We suggest that aspirin should not be stopped prior to surgery. Warfarin may be stopped if the patient's thromboembolic risk is low.

Anterior and posterior vitreous cysts.

Vitreous cysts are rare structural entities of uncertain aetiology. Although most do not produce troublesome visual symptoms, they can cause diagnostic difficulties in clinical practice. Two different types are described and the possible aetiologies of congenital and acquired vitreous cysts are discussed.