How to defuse a demographic time bomb: the way forward?

The Royal College of Ophthalmologists' National Ophthalmology Database Study of Cataract Surgery: Report 13, monitoring post-cataract surgery endophthalmitis rates-the rule of X

BACKGROUND

Cataract surgical safety has improved over recent decades, with endophthalmitis rates before 2006 typically 0.13-0.15% compared with the most recent UK national estimate of 0.02%. There remains, however, substantial variation in reported rates from different centres. Due to the low event rate, this disparity may not be noticed and opportunities to improve therefore be missed. We propose a method of monitoring post-cataract endophthalmitis rates that would help centres with higher rates identify this.

METHODS

A statistical tool, available to download or use online, permits comparison of local endophthalmitis rate with the estimated UK rate of 0.02%. Centres are encouraged to maintain a register of endophthalmitis cases, and when the number reaches a threshold (X cases), either in a certain time period or in a fixed number of procedures, then the centre can consider itself as an outlier and trigger local investigations to improve infection control.

RESULTS

Example outputs are offered, such as for a unit doing 5000 cataracts annually, a value of X is suggested such that the third case of endophthalmitis (X = 3) in a 12-month period would give 85% confidence, the fourth case 90% confidence and the fifth case 95% confidence that the true endophthalmitis rate for that unit was higher than the national average.

CONCLUSIONS

This statistical tool provides a basis for units to set a threshold number of cases of endophthalmitis within a given period that would trigger local processes, thus helping inform local monitoring processes for this rare but potentially catastrophic complication of cataract surgery.

Reliability of Visual Field Testing in a Telehealth Setting Using a Head-Mounted Device: A Pilot Study

PRCIS

Monitoring visual fields (VFs) through virtual reality devices proved to have good inter-test and test-retest reliability, as well as easy usability, when self-administered by individuals with and without VF defects in a remote setting.

PURPOSE

To assess the reliability of remote, self-administered VF monitoring using a virtual reality VF (VRVF) device in individuals without ocular disease and with stable VF defects.

MATERIALS AND METHODS

Individuals without ocular disease and with stable defects were recruited. All participants had a baseline standard automated perimetry (SAP) test. Participants tested remotely on a VRVF device for 4 weeks (examinations V 1 , V 2 , V 3 , and V 4 ), with the last 3 unassisted. The mean sensitivities of VRVF results were compared with each other and to SAP results for reliability.

RESULTS

A total of 42 eyes from 21 participants were tested on the VRVF device. Participants tested consistently although external factors impacted outcomes. VRVF results were in reasonable agreement with the baseline SAP. Examinations performed by the cohort with stable defects evinced better agreement with SAP examinations (V2, P = 0.79; V3, P = 0.39; V4, P = 0.35) than those reported by the cohort without ocular disease (V2, P = 0.02; V3, P = 0.15; V4, P = 0.22), where the null hypothesis is that the instruments agree. Fixation losses were high and variable in VRVF examinations compared with those of SAP, particularly in certain test takers. Participants considered the device comfortable and easy to use.

CONCLUSIONS

Self-administered, remote VF tests on a VRVF device showed satisfactory test-retest reliability, good inter-test agreement with SAP, and acceptability by its users. External factors may impact at-home testing and age and visual impairment may hinder fixation. Future studies to expand the sample size and understand inconsistencies in fixation losses are recommended.

The Royal College of Ophthalmologists' National Ophthalmology Database study of cataract surgery: Report 9, Risk factors for posterior capsule opacification

BACKGROUND/OBJECTIVES

Posterior Capsule Opacification (PCO) is the most common long-term post-operative adverse occurrence after cataract surgery often requiring treatment with YAG laser posterior capsulotomy. This study aimed to identify potential risk factors, known at the time of cataract surgery, that influence the development of PCO.

SUBJECT/METHODS

A retrospective study of publicly funded cataract surgery from The Royal College of Ophthalmologists' National Ophthalmology Database. Eligible for analysis were 500,872 cataract operations performed in 41 participating centres.

RESULTS

The 500,872 operations were performed on 243,167 (48.5%) left eyes and 257,705 (51.5%) right eyes from 373,579 patients by 2196 surgeons. Post-cataract PCO was recorded for 61,778 (12.3%) eyes and the six month, one, three, five and nine year observed rates of PCO were 2.3%, 4.4%, 19.7%, 34.0% and 46.9% respectively. Different PCO profiles were observed between IOL materials and the identified risk factors that increased the risk of developing PCO included hydrophilic IOL material, axial length >26 mm, the presence of high myopia and implantation of lower IOL powers and previous vitrectomy surgery, along with younger age and female gender.

CONCLUSIONS

Many factors influence the development of PCO relating to the patient, the eye, the lens and the surgery. Some factors are modifiable such as IOL material, therefore the opportunity exists to attempt to reduce PCO rates, benefitting patients and the UK NHS.

Cataracts

94 million people are blind or visually impaired globally, and cataract is the most common cause of blindness worldwide. However, most cases of blindness are avoidable. Cataract is associated with decreased quality of life and reduced life expectancy. Most cases of cataract occur after birth and share ageing and oxidative stress as primary causes, although several non-modifiable and modifiable risk factors can accelerate cataract formation. In most patients, phacoemulsification with intraocular lens implantation is the preferred treatment and is highly cost-effective. There has been an increase in the use of comprehensive cataract surgical services, including diagnoses, treatment referrals, and rehabilitation. However, global inequity in surgical service quality is still a limitation. Implementation of preoperative risk assessment, risk reduction strategies, and new surgical technologies have made cataract surgery possible at an earlier stage of cataract severity with the expectation of good refractive outcomes. The main challenge is making the service that is currently available to some patients accessible to all by use of universal health coverage.

Glaucoma Home Monitoring Using a Tablet-Based Visual Field Test (Eyecatcher): An Assessment of Accuracy and Adherence Over 6 Months

Purpose

To assess accuracy and adherence of visual field (VF) home monitoring in a pilot sample of patients with glaucoma.

Design

Prospective longitudinal feasibility and reliability study.

Methods

Twenty adults (median 71 years) with an established diagnosis of glaucoma were issued a tablet perimeter (Eyecatcher) and were asked to perform 1 VF home assessment per eye, per month, for 6 months (12 tests total). Before and after home monitoring, 2 VF assessments were performed in clinic using standard automated perimetry (4 tests total, per eye).

Results

All 20 participants could perform monthly home monitoring, though 1 participant stopped after 4 months (adherence: 98% of tests). There was good concordance between VFs measured at home and in the clinic (r = 0.94, P < .001). In 21 of 236 tests (9%), mean deviation deviated by more than ±3 dB from the median. Many of these anomalous tests could be identified by applying machine learning techniques to recordings from the tablets' front-facing camera (area under the receiver operating characteristic curve = 0.78). Adding home-monitoring data to 2 standard automated perimetry tests made 6 months apart reduced measurement error (between-test measurement variability) in 97% of eyes, with mean absolute error more than halving in 90% of eyes. Median test duration was 4.5 minutes (quartiles: 3.9-5.2 minutes). Substantial variations in ambient illumination had no observable effect on VF measurements (r = 0.07, P = .320).

Conclusions

Home monitoring of VFs is viable for some patients and may provide clinically useful data.

The Royal College of Ophthalmologists' National Ophthalmology Database study of cataract surgery: Report 7, immediate sequential bilateral cataract surgery in the UK: Current practice and patient selection

BACKGROUND

Cataract extraction is the most frequently performed surgical intervention in the world and demand is rising due to an ageing demography. One option to address this challenge is to offer selected patients immediate sequential bilateral cataract surgery (ISBCS). This study aims to investigate patient and operative characteristics for ISBCS and delayed bilateral cataract surgery (DSCS) in the UK.

METHODS

Data were analysed from the Royal College of Ophthalmologists' National Ophthalmology Database Audit (NOD) of cataract surgery. Eligible patients were those undergoing bilateral cataract extraction from centres with a record of at least one ISBCS operation between 01/04/2010 and 31/08/2018. Variable frequency comparison was undertaken with chi-square tests.

RESULTS

During the study period, 1073 patients had ISBCS and 248,341 DSCS from 73 centres. A higher proportion of ISBCS patients were unable to lie flat (11.3% vs. 1.8%; p < 0.001), unable to cooperate (9.7% vs. 2.7%; p < 0.001); underwent general anaesthesia (58.7% vs. 6.6% (p < 0.001)); had brunescent/white/mature cataracts (odds ratio (OR) 5.118); no fundal view/vitreous opacities (OR 8.381); had worse pre-operative acuity 0.60 LogMAR ISBCS vs. 0.50 (first) and 0.40 (second eye) DSCS and were younger (mean ages, 71.5 vs. 75.6 years; p < 0.001). Posterior capsular rupture (PCR) rates adjusted for case complexity were comparable (0.98% ISBCS and 0.78% DSCS).

CONCLUSIONS

ISBCS was performed on younger patients, with difficulty cooperating and lying flat, worse pre-operative vision, higher rates of known PCR risk factors and more frequent use of general anaesthesia than DSCS in centres recorded on NOD.

Artificial intelligence and deep learning in ophthalmology

Artificial intelligence (AI) based on deep learning (DL) has sparked tremendous global interest in recent years. DL has been widely adopted in image recognition, speech recognition and natural language processing, but is only beginning to impact on healthcare. In ophthalmology, DL has been applied to fundus photographs, optical coherence tomography and visual fields, achieving robust classification performance in the detection of diabetic retinopathy and retinopathy of prematurity, the glaucoma-like disc, macular oedema and age-related macular degeneration. DL in ocular imaging may be used in conjunction with telemedicine as a possible solution to screen, diagnose and monitor major eye diseases for patients in primary care and community settings. Nonetheless, there are also potential challenges with DL application in ophthalmology, including clinical and technical challenges, explainability of the algorithm results, medicolegal issues, and physician and patient acceptance of the AI 'black-box' algorithms. DL could potentially revolutionise how ophthalmology is practised in the future. This review provides a summary of the state-of-the-art DL systems described for ophthalmic applications, potential challenges in clinical deployment and the path forward.

Clinically applicable deep learning for diagnosis and referral in retinal disease

The volume and complexity of diagnostic imaging is increasing at a pace faster than the availability of human expertise to interpret it. Artificial intelligence has shown great promise in classifying two-dimensional photographs of some common diseases and typically relies on databases of millions of annotated images. Until now, the challenge of reaching the performance of expert clinicians in a real-world clinical pathway with three-dimensional diagnostic scans has remained unsolved. Here, we apply a novel deep learning architecture to a clinically heterogeneous set of three-dimensional optical coherence tomography scans from patients referred to a major eye hospital. We demonstrate performance in making a referral recommendation that reaches or exceeds that of experts on a range of sight-threatening retinal diseases after training on only 14,884 scans. Moreover, we demonstrate that the tissue segmentations produced by our architecture act as a device-independent representation; referral accuracy is maintained when using tissue segmentations from a different type of device. Our work removes previous barriers to wider clinical use without prohibitive training data requirements across multiple pathologies in a real-world setting.

Post-cataract eye drops can be avoided by depot steroid injections

There are over 400 000 cataract operations now being performed annually in the UK. With the majority of those patients being older people, comorbidities such as dementia or arthritis can prevent patients putting in their own post-operative eye drops. Where there is a lack of family or other support, district nursing services are often called upon to administer these eye drops, which are typically prescribed four times a day for 4 weeks, thus potentially totalling 112 visits for drop instillation per patient. To reduce the burden of these post-operative eye drops on district nursing services, administration of an intra-operative sub-Tenon's depot steroid injection is possible for cataract patients who then do not require any post-operative drop instillation. As a trial of this practice, 16 such patients were injected in one year, thus providing a reduction of 1792 in the number of visits requested. Taking an estimated cost of each district nurse visit of £38, this shift in practice potentially saved more than £68 000; the additional cost of the injection over the cost of eye drops was just £8.80 for the year. This practice presents an opportunity to protect valuable community nursing resources, but advocacy for change in practice would be needed with secondary care, or via commissioners.