Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where R L Johnston is active.

Publication


Featured researches published by R L Johnston.


Eye | 2009

The Cataract National Dataset electronic multi-centre audit of 55 567 operations: updating benchmark standards of care in the United Kingdom and internationally

P Jaycock; R L Johnston; H Taylor; M Adams; D M Tole; P Galloway; C Canning; J M Sparrow

AimsTo pilot the use of the Cataract National Dataset (CND) using multi-centre data from Electronic Patient Record (EPR) systems and to demonstrate the ability of the CND to deliver certain of its intended benefits, including detailed preoperative profiling of cataract surgery patients and updating of benchmark standards of care in the NHS and beyond.MethodsNHS departments using EPR systems to collect a minimum preoperative, anaesthetic, operative and postoperative data set, the CND, were invited to submit data, which were remotely extracted, anonymised, assessed for conformity and completeness, and analysed.ResultsFour-hundred and six surgeons from 12 NHS Trusts submitted data on 55 567 cataract operations between November 2001 and July 2006 (86% from January 2004). Mean age (SD) was 75.4 (10.4) years, 62.0% female. Surgery was for first eyes in 58.5%, under local anaesthesia in 95.5% and by phacoemulsification in 99.7%. Trainees performed 33.9% of operations. Preoperative visual acuity (VA) was 6/12 or better in 42.9% eyes overall, in 35.3% first eyes and in 55.3% second eyes. Complication rates included the following: posterior capsule rupture and/or vitreous loss of 1.92%, simple zonule dialysis of 0.46% and retained lens fragments of 0.18%. Postoperative VA of 6/12 or better (and 6/6 or better) was achieved for 91.0% (45.9%) of all eyes, 94.7% (51.0%) of eyes with no co-pathologies and 79.9% (30.2%) of eyes with one or more co-pathologies respectively.ConclusionsThe CND is fit for purpose, is able to deliver useful benefits and can be collected as part of routine clinical care via EPR systems. This survey confirms shifts in practice since the 1997–1998 UK National Survey with full conversion to phacoemulsification, better preoperative acuity, a halving of the surgical ‘index’ benchmark complication of posterior capsule rupture and/or vitreous loss, and improved VA outcomes.


BMJ | 2010

Bevacizumab for neovascular age related macular degeneration (ABC Trial): multicentre randomised double masked study.

Adnan Tufail; Praveen J. Patel; Catherine Egan; Philip Hykin; Lyndon da Cruz; Zdenek J. Gregor; Jonathan Dowler; Mohammed Majid; Clare Bailey; Quresh Mohamed; R L Johnston; Catey Bunce; Wen Xing

Objectives To evaluate the efficacy and safety of intravitreous bevacizumab injections for the treatment of neovascular age related macular degeneration. Design Prospective, double masked, multicentre, randomised controlled trial. Setting Three ophthalmology centres in the United Kingdom. Participants 131 patients (mean age 81) with wet age related macular degeneration randomised 1:1 to intervention or control. Interventions Intravitreous bevacizumab (1.25 mg, three loading injections at six week intervals followed by further treatment if required at six week intervals) or standard treatment available at the start of the trial (photodynamic treatment with verteporfin for predominantly classic type neovascular age related macular degeneration, or intravitreal pegaptanib or sham treatment for occult or minimally classic type neovascular age related macular degeneration). Main outcome measures Primary outcome: proportion of patients gaining ≥15 letters of visual acuity at one year (54 weeks). Secondary outcomes: proportion of patients with stable vision and mean change in visual acuity. Results Of the 131 patients enrolled in the trial, five patients did not complete the study because of adverse events, loss to follow-up, or death. In the bevacizumab group, 21 (32%) patients gained 15 or more letters from baseline visual acuity compared with two (3%) in the standard care group (P<0.001); the estimated adjusted odds ratio was 18.1 (95% confidence interval 3.6 to 91.2) and the number needed to treat was 4 (3 to 6). In addition, the proportion of patients who lost fewer than 15 letters of visual acuity from baseline was significantly greater among those receiving bevacizumab treatment (91% (59) v 67% (44) in standard care group; P<0.001). Mean visual acuity increased by 7.0 letters in the bevacizumab group with a median of seven injections compared with a decrease of 9.4 letters in the standard care group (P<0.001), and the initial improvement at week 18 (plus 6.6 letters) was sustained to week 54. Among 65 patients treated with bevacizumab, there were no cases of endophthalmitis or serious uveitis related to the intervention. All end points with respect to visual acuity in the study eye at 54 weeks favoured bevacizumab treatment over standard care. Conclusions Bevacizumab 1.25 mg intavitreous injections given as part of a six weekly variable retreatment regimen is superior to standard care (pegaptanib sodium, verteporfin, sham), with low rates of serious ocular adverse events. Treatment improved visual acuity on average at 54 weeks. Trial registration number Current controlled trials ISRCTN83325075


Eye | 2009

The Cataract National Dataset electronic multicentre audit of 55 567 operations: risk stratification for posterior capsule rupture and vitreous loss

N Narendran; P Jaycock; R L Johnston; H Taylor; M Adams; D M Tole; R H Asaria; P Galloway; J M Sparrow

AimsTo identify and quantify risk factors for posterior capsule rupture or vitreous loss or both (PCR or VL or both) during cataract surgery and provide a method of composite risk assessment for individual operations.MethodsThe Cataract National Dataset was extracted on 55 567 operations from 12 National Health Service (NHS) Trusts using an electronic patient record (EPR) system between November 2001 and July 2006. Risk indicators for variations in the rate of ‘PCR or VL or both’ were identified by univariate and multivariate analyses. Adjusted odds ratios (ORs) were used to formulate a composite ‘bespoke’ risk for individual cases.ResultsOverall ‘PCR or VL or both’ rate was 1.92% (95% CI=1.81–2.04%). Risk indicators for this complication were increasing age, male gender, presence of glaucoma, diabetic retinopathy, brunescent/white cataract, no fundal view/vitreous opacities, pseudo-exfoliation/phacodonesis, reducing pupil size, axial length ⩾26.0 mm, the use of the α-blocker doxazosin, inability to lie flat and trainee surgeons performing operations. Adjusted ORs for these variables are used to estimate overall composite risk across multiple risk indicators in the form of a predicted probability of PCR or VL or both. Predicted probability for this complication ranged from less than 0.75% to more than 75%, depending on risk profile of individual operations.ConclusionsHigher-risk cases can be predicted, thus better informing the consent process and allowing surgeons to take appropriate precautions. Case-mix is a major determinant of the probability of an intraoperative complication. A simple composite risk estimation system has been developed.


Eye | 2009

Benchmark standards for refractive outcomes after NHS cataract surgery

Richard Gale; M Saldana; R L Johnston; B Zuberbuhler; M McKibbin

PurposeTo establish benchmark standards for refractive outcome after cataract surgery in the National Health Service when implementing the 2004 biometry guidelines of the Royal College of Ophthalmologists and customising Aconstants.MethodsThree cycles of prospective data were collected throughout the cataract care pathway on all patients using an electronic medical record system (Medisoft Ophthalmology), between January 2003 and February 2006. The electronic medical record automatically recommends the formula to be used according to the College guidelines and allows Aconstants to be customised separately for either ultrasound or partial coherence interferometry methods of axial length measurement and for different intraocular lens models. Consultants and trainees performed routine phacoemulsification cataract surgery and new intraocular lens models were introduced during the cycles. Uncomplicated cases with‘in-the-bag fixation’, achieving 6/12 Snellen acuity or better were included. Community ophthalmic opticians performed refraction at 4 weeks.ResultsThe postoperative subjective refraction was within 1 D of the predicted value in 79.7% of the 952 cases in cycle 1, 83.4% of 2406 cases in cycle 2, and 87.0% of 1448 cases in cycle 3.ConclusionsOn the basis of our data, using College formula, optimising Aconstants and partial coherence interferometry, a benchmark standard of 85% of patients achieving a final spherical equivalent within 1 D of the predicted figure and 55% of patients within 0.5 D should be adopted.


Ophthalmology | 2016

Risk Factors and Incidence of Macular Edema after Cataract Surgery: A Database Study of 81984 Eyes

Colin Chu; R L Johnston; Charlotte Buscombe; Ahmed Sallam; Queresh Mohamed; Yit C. Yang

PURPOSE To define the incidence of pseudophakic macular edema (PME) after cataract surgery and to identify contributory risk factors. DESIGN Retrospective database study of electronic medical records (EMRs). PARTICIPANTS A total of 81984 eyes undergoing cataract surgery between December 2010 and December 2014 from 8 independent United Kingdom clinical sites. METHODS Structured clinical data mandated by the EMR were anonymized and extracted for each eye undergoing cataract surgery including: perioperative visual acuity, copathologic features, simultaneous surgical procedures, and the presence or absence of a specified list of intraoperative complications. Diabetic status with matched Early Treatment Diabetic Retinopathy Study (ETDRS) grading also was mandated by the EMR. Eyes receiving prophylactic nonsteroidal anti-inflammatory drugs were excluded. MAIN OUTCOME MEASURE Diagnosis of cystoid macular edema or new-onset macular edema in patients with diabetes, recorded by a healthcare professional within 90 days of surgery. RESULTS Baseline incidence of PME in eyes without operative complications, diabetes, or risk factors was 1.17%. Eyes in which PME developed were more likely to be male, older, and to demonstrate risk factors. The relative risk (RR) was increased in eyes with capsule rupture with or without vitreous loss (RR, 2.61; 95% confidence interval [CI], 1.57-4.34), a previous diagnosis of epiretinal membrane (RR, 5.60; 95% CI, 3.45-9.07), uveitis (RR, 2.88; 95% CI, 1.50-5.51), retinal vein occlusion (RR, 4.47; 95% CI, 2.56-5.92), or retinal detachment repair (RR, 3.93; 95% CI, 2.60-5.92). High myopia, age-related macular degeneration, or prostaglandin analog use were not shown to increase risk. Eyes with PME on average had poorer postoperative visual acuity, which persisted to the latest time point assessed, up to 24 weeks. Eyes from patients with diabetes, even in the absence of retinopathy, had an increased RR (RR, 1.80; 95% CI, 1.36-2.36) of new macular edema after surgery. The risk was higher in the presence of any diabetic retinopathy (DR; RR, 6.23; 95% CI, 5.12-7.58) and rose proportionately with increasing severity of DR. CONCLUSIONS Pseudophakic macular edema occurs commonly after phacoemulsification cataract surgery, even in the absence of complications and risk factors. This large retrospective study using structured EMR data quantified the RRs of PME and the risk with increasing ETDRS severity of DR. It highlights the need for prophylactic therapy, especially in those groups of eyes with the highest RRs.


Eye | 2015

Defining response to anti-VEGF therapies in neovascular AMD

Winfried Amoaku; Usha Chakravarthy; Richard Gale; M. Gavin; Faruque Ghanchi; Jonathan Gibson; Simon P. Harding; R L Johnston; S. Kelly; Andrew J. Lotery; Sajjad Mahmood; Geeta Menon; Sobha Sivaprasad; James Talks; Adnan Tufail; Yit C. Yang

The introduction of anti-vascular endothelial growth factor (anti-VEGF) has made significant impact on the reduction of the visual loss due to neovascular age-related macular degeneration (n-AMD). There are significant inter-individual differences in response to an anti-VEGF agent, made more complex by the availability of multiple anti-VEGF agents with different molecular configurations. The response to anti-VEGF therapy have been found to be dependent on a variety of factors including patient’s age, lesion characteristics, lesion duration, baseline visual acuity (VA) and the presence of particular genotype risk alleles. Furthermore, a proportion of eyes with n-AMD show a decline in acuity or morphology, despite therapy or require very frequent re-treatment. There is currently no consensus as to how to classify optimal response, or lack of it, with these therapies. There is, in particular, confusion over terms such as ‘responder status’ after treatment for n-AMD, ‘tachyphylaxis’ and ‘recalcitrant’ n-AMD. This document aims to provide a consensus on definition/categorisation of the response of n-AMD to anti-VEGF therapies and on the time points at which response to treatment should be determined. Primary response is best determined at 1 month following the last initiation dose, while maintained treatment (secondary) response is determined any time after the 4th visit. In a particular eye, secondary responses do not mirror and cannot be predicted from that in the primary phase. Morphological and functional responses to anti-VEGF treatments, do not necessarily correlate, and may be dissociated in an individual eye. Furthermore, there is a ceiling effect that can negate the currently used functional metrics such as >5 letters improvement when the baseline VA is good (ETDRS>70 letters). It is therefore important to use a combination of both the parameters in determining the response.The following are proposed definitions: optimal (good) response is defined as when there is resolution of fluid (intraretinal fluid; IRF, subretinal fluid; SRF and retinal thickening), and/or improvement of >5 letters, subject to the ceiling effect of good starting VA. Poor response is defined as <25% reduction from the baseline in the central retinal thickness (CRT), with persistent or new IRF, SRF or minimal or change in VA (that is, change in VA of 0+4 letters). Non-response is defined as an increase in fluid (IRF, SRF and CRT), or increasing haemorrhage compared with the baseline and/or loss of >5 letters compared with the baseline or best corrected vision subsequently. Poor or non-response to anti-VEGF may be due to clinical factors including suboptimal dosing than that required by a particular patient, increased dosing intervals, treatment initiation when disease is already at an advanced or chronic stage), cellular mechanisms, lesion type, genetic variation and potential tachyphylaxis); non-clinical factors including poor access to clinics or delayed appointments may also result in poor treatment outcomes. In eyes classified as good responders, treatment should be continued with the same agent when disease activity is present or reactivation occurs following temporary dose holding. In eyes that show partial response, treatment may be continued, although re-evaluation with further imaging may be required to exclude confounding factors. Where there is persistent, unchanging accumulated fluid following three consecutive injections at monthly intervals, treatment may be withheld temporarily, but recommenced with the same or alternative anti-VEGF if the fluid subsequently increases (lesion considered active). Poor or non-response to anti-VEGF treatments requires re-evaluation of diagnosis and if necessary switch to alternative therapies including other anti-VEGF agents and/or with photodynamic therapy (PDT). Idiopathic polypoidal choroidopathy may require treatment with PDT monotherapy or combination with anti-VEGF. A committee comprised of retinal specialists with experience of managing patients with n-AMD similar to that which developed the Royal College of Ophthalmologists Guidelines to Ranibizumab was assembled. Individual aspects of the guidelines were proposed by the committee lead (WMA) based on relevant reference to published evidence base following a search of Medline and circulated to all committee members for discussion before approval or modification. Each draft was modified according to feedback from committee members until unanimous approval was obtained in the final draft. A system for categorising the range of responsiveness of n-AMD lesions to anti-VEGF therapy is proposed. The proposal is based primarily on morphological criteria but functional criteria have been included. Recommendations have been made on when to consider discontinuation of therapy either because of success or futility. These guidelines should help clinical decision-making and may prevent over and/or undertreatment with anti-VEGF therapy.


Eye | 2015

The Royal College of Ophthalmologists’ National Ophthalmology Database study of cataract surgery: report 1, visual outcomes and complications

Alexander C Day; Paul H.J. Donachie; J M Sparrow; R L Johnston

AimsTo describe the outcomes of cataract surgery in the United Kingdom.MethodsAnonymised data on 180 114 eyes from 127 685 patients undergoing cataract surgery between August 2006 and November 2010 were collected prospectively from 28 sites. Outcome measures included intraoperative and postoperative complication rates, and preoperative and postoperative visual acuities.ResultsMedian age at first eye surgery was 77.1 years, 36.9% cases had ocular co-pathology and 41.0% patients underwent cataract surgery on both eyes. Preoperative visual acuity was 0.30 logMAR or better in 32.0% first eyes and 47.7% second eyes. Postoperative best-measured visual acuity was 0.00 and 0.30 logMAR or better in 50.8 and 94.6% eyes without ocular co-pathology, and 32.5 and 79.9% in eyes with co-pathology. For eyes without co-pathology, postoperative uncorrected distance visual acuity was 0.00 and 0.30 logMAR or better in 27.3 and 80.9% eyes. Posterior capsule rupture or vitreous loss or both occurred in 1.95% cases, and was associated with a 42 times higher risk of retinal detachment surgery within 3 months and an eight times higher risk of endophthalmitis.ConclusionThese results provide updated data for the benchmarking of cataract surgery. Visual outcomes, and the rate of posterior capsule rupture or vitreous loss or both appear stable over the past decade.


Eye | 2009

The Cataract National Dataset Electronic Multi-centre Audit of 55 567 operations: anaesthetic techniques and complications

N El-Hindy; R L Johnston; P Jaycock; T Eke; A J Braga; D M Tole; P H Galloway; J M Sparrow

PurposeThe primary aim of this study was to detail anaesthetic techniques and complications for cataract surgery in the UK.Methods The Cataract National Dataset was extracted from 12 National Health Service Trusts that used the same electronic patient record system between November 2001 and July 2006 on a total of 55 567 cataract operations.ResultsAnaesthesia was administered by an ophthalmologist in 56.7% of the cases, a career anaesthetist in 42.1% of the cases, a clinical assistant anaesthetist in 0.3% of the cases, and staff were not recorded in 0.9% of the cases. Local anaesthesia (LA) was used in 95.5%, with topical anaesthesia alone in 22.3% (range by site, 0–99.8%), topical and intracameral in 4.7% (range, 0–24.1%), subtenons in 46.9% (range, 0–81.8%), peribulbar in 19.5% (range, 0–63.4%), and retrobulbar in 0.5% (range, 0–5.3%). One or more minor complications occurred in 4.3% of 38 058 local blocks administered by either sharp needle or subtenons (blunt) cannula. Minor complications were 2.3 times more common with subtenons blocks (P<0.001). Serious complications, defined as sight or life threatening occurred in 25 eyes, 0.066%, undergoing sharp needle or subtenons cannula blocks. Sharp needle techniques had a 2.5-fold increased risk of serious complications compared with subtenons cannula techniques (P=0.026).ConclusionSubtenons anaesthesia was the most widely used anaesthetic technique for cataract surgery but wide variation existed by site. There was a low rate of reported LA complications. There was a statistically significant increased risk of serious complications with sharp needle anaesthesia compared with subtenons technique.


American Journal of Ophthalmology | 2014

Multicenter study of intravitreal dexamethasone implant in noninfectious uveitis: indications, outcomes, and reinjection frequency.

Javier Zarranz-Ventura; Ester Carreño; R L Johnston; Quresh Mohammed; Adam H Ross; Carl Barker; Alex Fonollosa; Joseba Artaraz; Laura Pelegrín; Alfredo Adán; Richard W J Lee; Andrew D. Dick; Ahmed Sallam

PURPOSE To identify clinical outcomes and treatment patterns of intravitreal dexamethasone implant (Ozurdex; Allergan, Inc) in noninfectious uveitis in the clinical setting. DESIGN Multicenter retrospective cohort study. METHODS Eighty-two eyes (63 patients) receiving 142 implant injections over 35 months were included. Treatment indication, uveitis diagnosis, visual acuity, intraocular pressure, vitreous haze score, central retinal thickness by optical coherence tomography, phakic status, number of injections, time to reinjection, systemic treatments, and complications data were collected. Time to visual acuity and vitreous haze score improvement as per the Standardization of Uveitis Nomenclature guidelines were also determined. RESULTS The probability of visual acuity improvement (≥0.3 logarithm of the minimal angle of resolution units improvement) was 39% at 1 month, 49% at 3 months, 52% at 6 months, and 58% at 12 months. Eyes with baseline vitritis (vitreous haze score ≥+0.5, n = 45) had a probability of vitreous haze score improvement (2-step decrease or change from +0.5 to 0) at 2 weeks of 41%, at 1 month 63%, at 3 months 73%, at 6 months 79%, and at 12 months 88%. In eyes that completed 12-month follow-up (n = 54), 40.7% underwent 2 injections (mean time to second injection of 6.6 ± 1.9 months) and 11.2% required ≥3 injections (mean time to third injection of 11 ± 1.5 months). CONCLUSIONS Dexamethasone implant use in uveitis provides favorable visual acuity and vitreous haze score outcomes but requires repeated injections, an important consideration when choosing intraocular treatment as a route to controlling uveitis.


Eye | 2013

United Kingdom National Ophthalmology Database Study of Vitreoretinal Surgery: Report 1; Case mix, complications, and cataract

Timothy L. Jackson; Paul H.J. Donachie; J M Sparrow; R L Johnston

AimTo report the vitreoretinal (VR) surgical case mix in the United Kingdom, the intraoperative complication rate of pars plana vitrectomy (PPV), and the incidence of post-vitrectomy cataract extraction.MethodsParticipating hospitals prospectively collected ophthalmic data using a single electronic medical record system, with automatic extraction of anonymised data to a national database. This study included the subset of 11 618 VR operations undertaken on 9619 eyes, of 8741 patients, over 8 years, from 27 sites. Surgical data included the indication for surgery, all procedure elements, and whether or not an intraoperative complication occurred. Post-vitrectomy cataract data were also analysed. The main outcome measures were a description of the indications for surgery, intraoperative PPV complication rate, and percentage of eyes undergoing post-vitrectomy cataract surgery (PVCS).ResultsThe most common indications for VR intervention were retinal breaks and rhegmatogenous retinal detachment (48.5%), macular hole (9.8%), epiretinal membrane (9.6%), and diabetic eye disease (7.3%). Overall, 7.8% of PPVs had at least one intraoperative complication—the most common were iatrogenic retinal breaks (3.2%), and lens touch (1.2–1.6% of phakic eyes). PVCS occurred in 50.2, 68.7, and 74.0% of eyes at 1, 2, and 3 years, respectively.ConclusionVR surgery is undertaken for a wide range of conditions, but a small number of diagnoses encompass the majority of cases. Intraoperative PPV complications are not uncommon, and post-vitrectomy cataract is to be expected in most phakic eyes.

Collaboration


Dive into the R L Johnston's collaboration.

Top Co-Authors

Avatar

Adnan Tufail

Moorfields Eye Hospital

View shared research outputs
Top Co-Authors

Avatar

Paul H.J. Donachie

Gloucestershire Hospitals NHS Foundation Trust

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Aaron Y. Lee

University of Washington

View shared research outputs
Top Co-Authors

Avatar

Ahmed Sallam

University of Arkansas for Medical Sciences

View shared research outputs
Top Co-Authors

Avatar

Clare Bailey

Northern Health and Social Care Trust

View shared research outputs
Top Co-Authors

Avatar

Usha Chakravarthy

Queen's University Belfast

View shared research outputs
Top Co-Authors

Avatar

M McKibbin

Leeds Teaching Hospitals NHS Trust

View shared research outputs
Top Co-Authors

Avatar

Quresh Mohamed

Cheltenham General Hospital

View shared research outputs
Researchain Logo
Decentralizing Knowledge