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Cataracts in adults: management. London: National Institute for Health and Care Excellence (NICE); 2017 Oct. (NICE Guideline, No. 77.)
10.1. Laser-assisted cataract surgery
Femtosecond lasers have been used to perform several stages of phacoemulsification cataract surgery since 2009 (Nagy et al., 2009). Laser generated pulses of highly focused infrared light (wavelength 1053nm) cut by creating localised cavitation bubbles within tissues, a process termed photo-disruption. The ultrashort duration of each pulse (10–15 femtoseconds) minimises damage to adjacent tissue. During cataract surgery, such lasers are used to create incisions, perform capsulorhexis, and fragment the lens. The procedure is then completed using conventional phacoemulsification equipment and techniques.
Potential advantages of laser-assisted cataract surgery over conventional phacoemulsification cataract surgery include:
- Reproducible incisions including, where necessary, additional incisions to reduce postoperative astigmatism
- Accurately centred, circular capsulotomies of a specified size. This may allow better long-term intraocular lens centration.
- Reduced corneal endothelial loss as a result of shorter phacoemulsification times and less intraocular fluid flow during surgery (Donaldson et al., 2013)
These potential advantages need to be weighed against the costs of purchasing and maintaining the laser (including employing a laser technician), the additional space required for the laser equipment, and increased operating time (Donaldson et al., 2013).
10.1.1. Review question
- What is the effectiveness of laser-assisted phacoemulsification cataract surgery compared with standard ultrasound phacoemulsification cataract surgery?
10.1.2. Introduction
This review was undertaken by the Cochrane Eyes and Vision Group, in collaboration with the NICE Internal Clinical Guidelines Team.
The aim of this review was to compare the effectiveness of laser assisted phacoemulsification cataract surgery with standard ultrasound phacoemulsification cataract surgery and gather evidence on safety from randomised controlled clinical trials.
The review focused on identifying studies that fulfilled the conditions specified in Table 33. For full details of the review protocol, see Appendix C.
Table 33
PICO inclusion criteria for the review questions on laser-assisted surgery.
Randomised controlled trials (RCTs) were included if they compared laser-assisted phacoemulsification cataract surgery with standard ultrasound phacoemulsification cataract surgery. Papers were excluded if they:
- were guidelines, narrative reviews, case studies/reports, case series, reliability studies, diagnostic accuracy studies, non-comparative studies
- included animals, healthy eyes, other ocular conditions besides cataracts or mixed primary populations of people with different eye pathologies
- reported studies conducted entirely in non-OECD countries
- were not published in the English language.
For the list of excluded studies with reasons, see Appendix F.
10.1.3. Evidence review
In total, 1,435 unique references were found for this review question, and full-text versions of 38 citations that seemed potentially relevant to this topic were retrieved. Sixteen studies were identified which met the inclusion criteria, 11 were excluded and 11 were ongoing studies where results have not yet been published.
No additional relevant studies were identified in the update searches undertaken at the end of the guideline development process.
10.1.3.1. Description of included studies
Full details of the included studies are found in the evidence tables (see Appendix E). Sixteen RCTs were identified for inclusion in the review, of which 5 were within-person studies where 1 eye of each participant had manual phacoemulsification and the other eye laser-assisted cataract surgery (Conrad-Hengerer 2013; Conrad-Hengerer 2014, Dick 2014, Schargus 2015; Conrad-Hengerer 2015). Eleven studies were parallel group randomised controlled trials (Nagy 2011, Filkorn 2012, Kránitz 2012, Takács 2012, Reddy 2013; Nagy 2014; Kovacs 2014; Mastropasqua 2014a, Mastropasqua 2014b, Hida 2014; Yu 2015).
10.1.4. Health economic evidence
A literature search was conducted jointly for all review questions in this guideline by applying standard health economic filters to a clinical search for cataracts. A total of 4,306 references were retrieved, of which 1 was retained for this review question.
Abell et al. (2014) conducted a cost–utility analysis of laser-assisted vs standard ultrasound phacoemulsification using a decision tree model. The payer perspective was the private secondary care provider with direct patient and Australian Medicare costs included. The model considers a hypothetical cohort of patients undergoing cataract surgery on the better-seeing eye. Utilities in the model were calculated according to a mathematical relationship between visual acuity and HRQoL proposed based on studies by Brown et al. (1999 & 20020, Lansingh et al. (2009), and Saw et al. (2005) which is given as:
- y = utility
- x = VA in LogMAR units
The authors used data on the effectiveness of phacoemulsification taken from the Swedish National Cataract Registry, a multicentre prospective trial (Hahn et al. 2010) and a large cohort study from a tertiary centre in Germany (Hoffman et al. 2011). In the absence of any equivalent evidence on laser-assisted surgery, Abell et al. (2014) assumed that the benefit of femtosecond surgery would be a 5% improvement in the number of eyes achieving ~6/12 visual acuity after surgery The increase in best corrected visual acuity (BCVA) after cataract surgery in the laser group was assumed to reflect improved refraction owing to improved lens positioning as a result of more regular capsulotomy incisions, as well as a decrease in the intraoperative complication rate. Based on the simulated complication rates of standard and laser-assisted surgery and assuming visual acuity improvement of 5% in uncomplicated cases, laser-assisted surgery was associated with QALY gains of 0.06, but was also found to have increased costs, with a resulting ICER of $AUS92,862 per QALY gained, which is above conventional thresholds of cost effectiveness. Multivariable sensitivity analyses revealed that laser-assisted surgery would need to significantly improve visual outcomes and complications rates over standard surgery, along with a reduction in cost to patient, to improve cost effectiveness. Modelling a best-case scenario of laser-assisted surgery with excellent visual outcomes (100% achieving >6/12 vision), a significant 0% complication rate and a significantly reduced total cost to the patient of $AUS300 resulted in an ICER of $AUS20,000 per QALY. The evidence table for the study is included in Appendix E.
10.1.5. Evidence statements
10.1.5.1. Intraoperative complications
Very low-quality evidence from 10 RCTs containing 1,076 participants could not differentiate rates of anterior capsule tear or posterior capsule tear between people given laser-assisted cataract surgery and those given standard ultrasound phacoemulsification.
10.1.5.2. Postoperative complications
Low-quality evidence from up to 9 RCTs containing 957 participants could not differentiate rates of cystoid macular oedema or elevated intraocular pressure between people given laser-assisted cataract surgery and those given standard ultrasound phacoemulsification.
10.1.5.3. Visual acuity
Low-quality evidence from 3 RCTs containing 338 participants could not detect a clinically meaningful difference in postoperative levels of visual acuity (logMAR) between people given laser-assisted cataract surgery and those given standard ultrasound phacoemulsification.
10.1.5.4. Duration of procedure
Low-quality evidence from 3 RCTs containing 274 participants could not differentiate total procedure duration between people given laser-assisted cataract surgery and those given standard ultrasound phacoemulsification.
10.1.5.5. Health economic evidence
One partly applicable study with potentially serious limitations suggests that laser-assisted cataract surgery is not cost effective when compared with standard phacoemulsification techniques.
10.1.6. Evidence to recommendations
| Relative value of different outcomes | The guideline committee stated that improvements in either visual outcomes or complication rates with laser-assisted cataract surgery would be relevant, as would differences in procedure duration. It would also be important to consider the inclusion criteria of the studies, as laser-assisted surgery may only be practical in certain groups of patients (e.g. those with cataracts which the laser is capable of breaking up). The committee discussed whether it should consider measures of endothelial cell loss as a relevant example of intraoperative or postoperative complications. It noted that this outcome is only indirectly relevant to patients – they are very unlikely to experience worse or better quality of life as an immediate consequence of more or less endothelial damage. However, if endothelial cell loss is a reliable surrogate indicator of long-term sequelae, any differences between approaches could arguably be deemed indirectly meaningful. In particular, the committee noted that there may be an association between endothelial cell loss and corneal decompensation leading, in turn, to a need for corneal grafting. However, the committee were not convinced that a clear surrogate relationship was present, at levels of endothelial cell loss seen in modern-day cataract surgery. Committee members agreed that, while rates of corneal grafting in pseudophakic eyes had risen a little in the early days of phacoemulsification surgery, more modern techniques had rendered this an extremely rare outcome. Therefore, even if it could be shown that an alternative approach results in reduced endothelial cell loss, it is far from certain that this would translate into meaningful benefits for the patient. The committee also agreed that the patient-relevant long-term sequelae that may be associated with increased endothelial damage were, themselves, outcomes that should be captured in the review. Therefore, the priority should be to assess whether there is any meaningful difference in these outcomes, rather than to focus on an uncertain surrogate predictor of them. |
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| Trade-off between benefits and harms | The committee agreed that there was no evidence to suggest a clinical difference between using laser assisted and standard phacoemulsification surgery. Whilst the trials in this area had quite small sample sizes, they did not demonstrate any meaningful improvements in visual acuity, visual function or complication rates. The only statistically significant difference was a 1–1.5 letter improvement in corrected visual acuity at 6 months, and this was judged by the committee not to be a clinically meaningful difference, particularly as it was not replicated at other time points, nor was a difference identified in uncorrected visual acuity. The committee therefore agreed it would be inappropriate for laser-assisted cataract surgery to be regularly used. However, the committee also agreed that, because of the relative scarcity and low quality of the evidence base, and the fact there are specific situations where laser-assisted surgery may have benefits (for example, to improve outcomes for inexperienced surgeons), there could still be value in additional trials comparing laser-assisted surgery with ultrasound phacoemulsification in this situation. Whilst the committee did not feel this need was sufficient to justify recommending future trials (particularly in view of current trials known to be ongoing such as the NIHR funded FACT study), it agreed that it would be appropriate to recommend that the use of laser-assisted surgery could be justified only within the context of clinical trials. |
| Consideration of health benefits and resource use | The committee agreed that the economic evidence presented was neither directly relevant to the decision problem at hand nor particularly robust, with large amounts of the parameter inputs being based solely on assumptions. Nevertheless, the committee agreed that it still provided useful evidence to inform its decision, as it demonstrated that the benefits it would be necessary for laser-assisted surgery to achieve in order to be cost effective at a population level were much larger than those shown by currently published trials. However, the committee are aware of two large trials with associated health economic evaluations that are due to publish in the next 12 months; (the FACT trial in the UK and the FEMCAT trial in France) which may offer new evidence. The committee also considered that additional research could be undertaken to examine whether femtosecond laser-assisted surgery enables greater surgical throughput and therefore has health-economic benefits with regard to increasing capacity which may offset the higher costs of the procedure compared to standard phacoemulsification. For these reasons, the committee felt an ‘only in research’ recommendation was appropriate, and that it shoud be particularly specified that this research collect resource use data, as this will be a key element in deciding on the long-term place of laser assistance in cataract surgery. The committee also noted that there is not only a cost associated with the initial purchase of the laser itself, but also an additional incremental cost for each surgery undertaken, because of required disposables. There are also problems with docking the laser on some patients whose eye characteristics fall outside certain ranges. Therefore, simply having a laser available would not mean that it should be automatically used in all possible procedures. |
| Quality of evidence | The committee noted that the evidence presented, although of low quality, was largely in line with current clinical opinion and that, although the exclusion criteria in the trials seemed extensive, they were reasonable and unlikely to impact on the overall pattern of the evidence. |
| Other considerations | No other considerations were identified as part of this review question. |
10.1.7. Recommendations
- 33.
Only use femtosecond laser-assisted cataract surgery as part of a randomised controlled trial that includes collection of resource-use data, comparing femtosecond laser-assisted cataract surgery with ultrasound phacoemulsification.
10.2. Bilateral surgery
At present, the majority of patients presenting with bilateral cataracts undergo sequential surgery with an intervening period between operations of weeks or months. This provides opportunities to identify and treat any postoperative complications related to the first-eye surgery and, if necessary, modify the choice of intraocular lens for the second eye according to the refractive outcome of the first operation. However, the risk of complications for patients without ocular comorbidities is small, and patients undergoing sequential surgery may experience significant difficulty with anisometropia whilst waiting for the second-eye operation. Furthermore, the interval between procedures delays the time at which patients regain their full visual potential. Bilateral simultaneous (rapid sequential) cataract surgery may, therefore, offer functional benefits to patients. Such surgery may also have cost advantages in terms of theatre efficiency, and reduced numbers of hospital appointments for the patient.
Some surgeons are now offering bilateral simultaneous cataract surgery to selected patients. During such procedures, the patient usually stays on the operating table after successful completion of the first eye surgery, and new drapes, instruments, irrigating lines and solutions are used for the second eye. Selection criteria for bilateral simultaneous cataract surgery typically include:
- No vision threatening ocular co-morbidities
- No evidence of lens instability
- Axial lengths within a range of 21 to 27 mm
10.2.1. Review questions
- What is the effectiveness of bilateral simultaneous (rapid sequential) cataract surgery compared with unilateral eye surgery?
- What is the appropriate timing of second eye surgery, taking into account issues such as refractive power after first eye surgery?
10.2.2. Introduction
The aim of this review was to identify the correct timing for second eye cataract surgery, and in particular:
- The effectiveness and safety of bilateral simultaneous (‘rapid sequential’) cataract surgery compared with staged unilateral (‘bilateral sequential’) surgery.
- If bilateral sequential surgery is undertaken, the correct timing of second eye surgery (which included never undertaking surgery as an option).
The review focused on identifying studies that fulfilled the conditions specified in Table 34. For full details of the review protocol, see Appendix C. The main outcomes for this review were visual acuity, visual function and quality of life after surgery, surgical complication rates, patient satisfaction and resource use/costs.
Table 34
PICO inclusion criteria for the review questions on second eye surgery.
Randomised controlled trials (RCTs) and systematic reviews of RCTs were included if they either compared same-day bilateral cataract surgery with different-day bilateral cataract surgery, or compared differing lengths of timing between different-day bilateral cataract surgeries. Papers were excluded if they:
- were narrative reviews, case studies/reports, case series, reliability studies, diagnostic accuracy studies, non-comparative studies
- included animals, healthy eyes, other ocular conditions besides cataracts or mixed primary populations of people with different eye pathologies
- reported studies conducted entirely in non-OECD countries
- were not published in the English language.
For the list of excluded studies with reasons, see Appendix F.
10.2.3. Evidence review
In total, 1,772 references were found for these review questions, and full-text versions of 29 citations that seemed potentially relevant to this topic were retrieved. Three unique RCTs were included (Lundström et al., 2006; Sarikkola et al., 2011; Serrano-Aguillar et al., 2011) focusing on bilateral simultaneous versus bilateral sequential cataract surgery for people with bilateral cataracts; and 3 RCTs were included (Castells et al., 2006; Foss et al., 2006; Laidlaw et al., 1998) looking at the additional value of doing versus not doing second-eye cataract surgery. Six systematic reviews were also identified for this population (Frampton et al., 2014; Gillespie et al., 2012; Ishikawa et al., 2013; Kessel et al., 2015; Lamoureux et al., 2011; Malvankar-Mehta et al., 2015) but these did not provide any additional information that was not available from the RCTs themselves. No RCTs were identified looking at different timings of bilateral sequential cataract surgery.
No additional relevant studies were identified in the update searches undertaken at the end of the guideline development process.
10.2.3.1. Description of included studies
The included studies are summarised in Table 35; full details are found in the evidence tables (see Appendix E). All 6 identified primary studies were randomised controlled trials, 3 comparing same day bilateral cataract surgery with different day bilateral cataract surgery and 3 comparing two eye cataract surgery with single eye cataract surgery for people with bilateral cataracts.
Table 35
Summary of included studies.
10.2.4. Health economic evidence
A literature search was conducted jointly for all review questions in this guideline by applying standard health economic filters to a clinical search for cataracts. A total of 4,306 references were retrieved, of which 4 were included for these review questions. Health economic evidence tables for these studies are provided in appendix J. An original health economic model was also available to the committee for this review question, and is described in section 6.1.4.2 of this Guideline and in Appendix J.
10.2.4.1. Bilateral simultaneous versus bilateral sequential
Malvankar-Mehta et al. (2013) developed a decision-tree model of immediate sequential compared with delayed sequential bilateral cataract surgery (ISBCS vs DSBCS). Patients in the DSBCS arm had immediate surgery on 1 eye and then the second eye within a 3-month window if they elected to undergo the second surgery. HRQoL was estimated using the patient preference values generated from visual acuity states in Brown et al. (2000). Surgery was either classified as ‘successful’ or as a ‘failure’, with failure meaning that an intraoperative or postoperative adverse event (endophthalmitis, CMO, or ‘other complication’) occurred. Visual acuity outcomes for endophthalmitis were based on a 1991 study of vitrectomy procedures (Doft, 1991) whereas all other success/failure rates and outcomes were taken from a single Canadian hospital. The relative effectiveness of ISBCS and DSBCS was based on expert opinion. In the base-case analysis, ISBCS dominated DSBCS (was more effective and less costly). A one-way sensitivity analysis did not change this result.
Table 36
Base-case results from Malvankar-Mehta et al. (2013).
10.2.4.2. Second-eye surgery versus no second-eye surgery
Busbee et al. (2003) developed a decision-tree-based cost–utility analysis of second-eye surgery based on data from the Patients Outcomes Research Team (PORT) study in the USA, which included 722 participants (mean age 72) undergoing cataract extraction surgery. The comparator was unilateral pseudophakia, and costs and QALY gains were considered over a life expectancy time horizon. The model included costs for cataract surgery, ambulatory and surgical procedures and retinal procedures. It also included drug expenditure costs associated with cataract surgery for medical and postoperative management. The cost of cataract surgery and management of endophthalmitis, intraocular lens dislocation, cystoid macular oedema and lost lens fragments was assumed to occur close to the initiation of cataract management whereas posterior capsule opacification (PCO) and retinal detachment incurred costs at the mean time of treatment after surgery. No cost information was included for unilateral pseudophakia, and the model assumed that the postoperative visual acuity in the second eye was equal to that of the first-eye surgery. Second-eye cataract surgery resulted in a gain of 0.92 quality-adjusted life-years (QALYs) over 12 years (discounted at 3% per annum). Second-eye cataract surgery resulted in a total discounted health-care cost of US$2,509, giving an estimated cost–utility of second-eye cataract surgery of US$2,727 per QALY gained. No incremental analysis was conducted.
Sach et al. (2010) conducted a cost–utility analysis as part of a trial of second-eye cataract surgery (Foss et al., 2006). The cohort was women over 70 years of age with a history of successful cataract surgery and an operable cataract in the absence of other ocular comorbidities. The comparison was patients on a watchful waiting list. HRQoL was measured using the EQ-5D, and the payer perspective was NHS and PSS with carer costs included in an additional scenario analysis. The mean total cost per patient for the lifetime analysis was £12,171 and £10,887 in the operated and the control group, respectively. The incremental cost effectiveness ratio (ICER) for surgery in the base case was £17,299 per QALY gained. The authors discuss the limitations of the EQ-5D for detecting both the quality of life of patients with a cataract prior to surgery and the gain in HRQoL incurred through surgery, highlighting this as a possible reason for their comparatively high ICERs relative to other studies.
Frampton et al. (2014) developed a cost–utility model based on a systematic review of the clinical effectiveness and cost effectiveness of second-eye cataract surgery. They identified 3 randomised controlled trials (RCTs) of clinical effectiveness, 3 studies of cost effectiveness and 10 studies of health-related quality of life (HRQoL) which met their inclusion criteria and, where possible, were used to inform their economic analysis. Studies did not provide evidence that second-eye surgery significantly affected HRQoL, apart from an improvement in the mental health component of HRQoL as measured by the HUI (Health Utility Index-3) in 1 RCT. The health economic analysis was conducted from the NHS and PSS perspective. It simulated a cohort of patients undergoing either second-eye surgery or continued as unilateral pseudophakia cases. In the surgery arm, people underwent successful surgery or had an intraoperative or late complication (endophthalmitis, retinal detachment, PCO, cystoid macular oedema (CMO), lost-lens fragments; with risks for PCO and retinal detachment modelled time-dependently on a lifetime and 3-year time horizon respectively). Utility losses and costs for adverse events were applied for 1 year, with costs and QALYs discounted at 3.5% per annum. Second-eye surgery generated 0.68 incremental QALYs with an ICER of £1,964. Model results were most sensitive to changes in the utility gain associated with second-eye surgery, but the procedure remained well below conventional limits at £5,734/QALY even when a utility gain of as low as 0.02 was modelled. The model was otherwise robust to changes in parameter values. The probability that second-eye surgery is cost effective at QALY thresholds of £10,000 and £20,000 was 100%.
Table 37
Base-case results from Frampton et al. (2014).
An original economic analysis, described in section 6.1.4.2 of this Guideline, suggestes that for second-eye cases, immediate cataract surgery is shown to be cost effective compared with no surgery in most scenarios, even if it confers no immediate HRQoL gain. This is because, as with the first-eye surgery, immediate surgery avoids future QALY losses and costs incurred by leaving the cataract(s) to progress until death. Compared with the first eye, there are slightly more scenarios in which HRQoL gain is necessary to produce an ICER lower than £20,000 / QALY; however, in common with the first eye, all these relate to people aged 90. In most cases, these scenarios also feature a high risk of visual loss. A very similar pattern is shown when comparing no surgery with delayed surgery with an acuity threshold of 6/12: most people are predicted to benefit from immediate surgery even if it confers no HRQoL gain and, in those cases where a gain of HRQoL is necessary to justify the slightly higher cost of immediate surgery, this benefit only has to be of ‘very small’ magnitude. All these scenarios relate to 90-year-olds and most feature a high risk of visual loss.
Whilst it was not possible, because of structural constraints, to run any probabilistic sensitivity analyses for the model, some deterministic sensitivity analyses were run. These included simulating a more rapid deterioration of VA in people with cataract; including wider NHS costs that would typically fall outside of the NICE reference case; and modelling an alternative acuity threshold of 6/9 in the delayed surgery arm. The model behaved as expected in these scenarios, with faster progression making immediate surgery more cost effective in all cases, regardless of risk factors. Including wider costs, or changing the acuity threshold to 6/6 increased the margin by which cataract surgery, in either eye, has to improve HRQoL for 90 year old patients with higher risk profiles. A full description of the sensitivity analyses is given in Appendix J.
10.2.5. Evidence statements
10.2.5.1. Bilateral simultaneous versus bilateral sequential
10.2.5.1.1. Complication rates
Low- to moderate-quality evidence from 2 RCTs containing 2,613 eyes did not identify meaningful differences in levels of intraoperative, postoperative or serious postoperative complications between people undergoing bilateral simultaneous cataract removal and those undergoing sequential surgery.
10.2.5.1.2. Visual function
High-quality evidence from 1 RCT containing 807 participants found subjective visual function (as measured by the VF-14) improved more in people who received immediate sequential surgery than in those in whom second-eye surgery was delayed, before second-eye surgery in the delayed group.
Moderate-quality evidence from 2 RCTs containing 1,298 participants could not differentiate changes in visual function 1 month after second-eye surgery between people who received immediate sequential surgery and those in whom second-eye surgery was delayed.
Moderate-quality evidence from 1 RCT containing 751 participants could not differentiate changes in visual function 1 year after surgery between people who received immediate sequential surgery and those in whom second-eye surgery was delayed.
10.2.5.1.3. Pain during surgery
Moderate-quality evidence from 1 RCT containing 993 participants could not differentiate the proportions of individuals experiencing pain during surgery between people who received immediate sequential surgery and those in whom second-eye surgery was delayed.
10.2.5.1.4. Patient satisfaction
High-quality evidence from 1 RCT containing 989 participants found there were no meaningful differences in the proportions of people very satisfied with their surgery between people who received immediate sequential surgery and those in whom second-eye surgery was delayed.
Moderate-quality evidence from 1 RCT containing 491 participants could not differentiate the levels of satisfaction with vision after second-eye surgery between people who received immediate sequential surgery and those in whom second-eye surgery was delayed.
10.2.5.1.5. Deviation from target refraction
High-quality evidence from 1 RCT containing 982 eyes found there were no meaningful differences in the proportions of people with a deviation from target refraction <0.5 or <1.0 dioptres between people who received immediate sequential surgery and those in whom second-eye surgery was delayed.
10.2.5.1.6. Visual acuity
Very low-quality evidence from 3 RCTs containing 1,386 participants could not differentiate changes in median visual acuity from preoperative to post-second-eye surgery between people who received immediate sequential surgery and those in whom second-eye surgery was delayed.
10.2.5.1.7. Health economics
One partially applicable CUA with serious limitations suggests that immediate sequential cataract surgery dominates (is more effective and cheaper than) delayed sequential surgery, although uncertainty around the estimate of cost effectiveness could not be reliably established.
10.2.5.2. Second-eye surgery versus no second-eye surgery
High-quality evidence from 3 RCTs containing 685 participants found higher levels of best-corrected visual acuity (logMAR) and binocular contrast sensitivity (measured using a Pelli–Robson chart) in people offered second-eye surgery versus no surgery.
High-quality evidence from 1 RCT containing 274 participants found higher levels of improvement in stereopsis (measured using the Titmus circles, Fly and TNO tests, reported in log seconds of arc), self-reported trouble with vision (measured using a 4 item Likert scale) and self-reported satisfaction with vision (measured using a 4 item Likert scale) for people offered second-eye surgery versus no surgery.
High-quality evidence from 2 RCTs containing 503 participants found higher levels of visual function (measured using the VF-14) in people offered second-eye surgery versus no surgery.
Moderate-quality evidence from 1 RCT containing 229 participants could not differentiate the risk of falls or changes in quality of life (as measured by the EQ-5D) between people offered second-eye surgery versus no surgery.
10.2.5.2.1. Health economics
One partially applicable cost–utility analysis from the USA with very serious limitations suggests that second-eye cataract surgery is cost effective under the condition that the gains in visual acuity and HRQoL are at least as large as those generated by the first-eye surgery.
One directly applicable study with minor limitations suggests that second-eye surgery is cost effective compared with unilateral surgery in an NHS context. In a probabilistic sensitivity analysis, the probability that second-eye surgery is cost effective at a willingness-to-pay threshold of £20,000 per QALY was 100%.
One directly applicable CUA, with potentially serious limitations found that second-eye surgery is cost effective when a lifetime time-horizon is considered, and wider costs to carers are excluded from the analysis.
One directly applicable original health economic analysis with potentially serious limitations suggests that for second eyes:
- 1)
Cataract surgery is cost effective compared with no surgery in most scenarios, even if it confers no immediate HRQoL gain.
- 2)
Compared with delayed surgery, most people derive cost-effective benefit from immediate surgery even if it confers no HRQoL gain and, in older, higher-risk cases where a gain of HRQoL is necessary to justify the slightly higher cost of immediate surgery, this benefit only has to be of ‘very small’ magnitude (see Appendix J).
The model results were somewhat sensitive to the inclusion of ‘unrelated’ costs after surgery for first and second eyes, and the assumed rate at which visual acuity declines in symptomatic eyes.
10.2.6. Evidence to recommendations
| Relative value of different outcomes | The committee noted that the relevant outcomes for this comparison were the trade-off between short and long-term differences in visual outcomes, compared with the risk of more serious complications with simultaneous surgery. Committee members agreed that the best available outcomes measures would be vision, health-related quality of life and patient satisfaction, but that, in the absence of these measures, visual acuity, visual function, contrast sensitivity and stereopsis would together provide proxies for at least a substantial proportion of the pre- to post-surgery changes. |
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| Trade-off between benefits and harms | The committee agreed that the evidence demonstrated a clear clinical benefit from second-eye surgery, compared to no second-eye surgery, across a range of domains including visual acuity, visual function, contrast sensitivity and patient satisfaction. Therefore, the key decision would be around the cost effectiveness of second-eye surgery, as discussed in the section on health benefits and resource use below. The committee noted that the studies provided no evidence of differences in long-term visual outcomes, or of rates of common intra- or postoperative complications between same-day and different-day bilateral surgery. The key trade-off was therefore identified as being between short-term benefits with simultaneous surgery versus the risk of more severe complications. Simultaneous surgery gave better outcomes in the period before second-eye surgery in the sequential group, with the duration of these additional benefits depending on the time between sequential in the sequential group. Conversely, simultaneous surgery had the potential for more severe adverse events, as it is possible that loss of vision in both eyes could result from a single error, whilst in the sequential group only 1 eye would be damaged through a single mistake. The committee noted that it is still unclear what the likelihood of severe complications (damage to both eyes) is with simultaneous surgery, and therefore people should be given specific information about the potential for additional risks whenever same-day surgery is being considered. The committee agreed it was therefore appropriate that a ‘consider’ recommendation be made for bilateral simultaneous cataract surgery, but did not feel it appropriate to make a stronger recommendation than this, both because of the lack of robust data on rare adverse events, and because of the relatively restrictive inclusion criteria in the RCTs. They also agreed that, for people at a low risk of ocular complications, there was no overwhelming clinical reason to prefer one timing of second surgery to another, and therefore it was important for people to be given information on the potential benefits and harms of both approaches, in order for them to be able to make an informed decision. No evidence was found to inform any recommendations about the appropriate length of time between procedures performed on different days. Some participants in the control arms of the trials did have intraocular lens adjustments after the first surgery in an attempt to improve second surgery outcomes, and the committee noted that the gap between surgeries needs to be large enough for the refraction to have stabilised after surgery. However, in the absence of any evidence, the committee did not feel it was appropriate to recommend a specific length of time between first and second eye surgeries. |
| Consideration of health benefits and resource use | The committee considered the modelling study by Malvankar-Mehta et al. (2013) in the light of the clinical evidence presented at the meeting, and discussed in particular the contrasts between the carefully selected populations included in the clinical studies and the hypothetical cohort included in the model. The committee was uncomfortable with the model’s lack of external validity; success rates for surgery, adverse event rates, and the rate at which patients elected to have second-eye surgery were all based on the clinical experience of clinicians at a single centre. The committee noted that it would have been possible, given the availability of published evidence in this domain, to undertake a fuller sensitivity analysis of these parameters using evidence external to the centre. The committee considered that there may have been some pressure on the centre to not use data other than expert opinion for surgical outcomes, and that this was a potential source of bias in the analysis. In common with the evidence presented for the questions on indicators and thresholds for surgery (chapter 6), the committee felt that the true costs of adverse events and their HRQoL implications were underestimated by the model, and that the apparent difference in absolute costs between delayed and immediate sequential surgery was primarily driven by the need for two admissions in the delayed surgery arm, and that this cost appeared overestimated. The committee agreed that the small incremental utility gain noted by Sach et al. (2010) and Frampton et al. (2014) was conservative, and was likely driven by the lack of sensitivity of the EQ-5D to both the pre-surgical morbidity of cataract, and the post-surgical gain in HRQoL. Furthermore, these analyses assumed that the difference in utility between second-eye surgery and no second-eye surgery was constant until death, and as Sach et al (2010) note in their conclusions, this is unrealistic as non-operated cataracts are likely to incur a decrease in visual acuity over time, with related HRQoL losses which could be prevented by offering surgery. The committee felt that the one-year time horizon in Sach et al. was not appropriate, as the benefits (and some potential harms) from surgery were likely to be lifelong. Shorter timescales would also inflate the true lifetime costs by excluding discounting. The committee broadly agreed with the costs included in these studies, although it noted that the carercosts included in a sensitivity analysis in Sach et al. are not included in the NICE reference case. The committee noted the increased nonocular NHS costs following cataract surgery (driven by greater uptake of GP visits, A&E appointments, and nurse visits in the surgery group), and expressed the view that these were somewhat surprising. One possible explanation was that improving people’s visual impairment empowers them to seek healthcare for other issues; another is that simply being in the hospital environment increases the likelihood of accessing other services. However, the committee understood that such costs should usually be considered as ‘unrelated’ and therefore excluded from consideration in the NICE reference case. The committee noted that the systematic review of effectiveness evidence in Frampton (2014) meant that the model was parameterised with data that is now 10 years old, and that in that time surgical outcomes have continued to improved and more second-eye surgeries are being performed. Furthermore, the committee discussed how the modelled cohort did not reflect the range of acuity and morbidity seen in clinical practice, and noted that the cohort had generally good preoperative acuity which would tend to make the reported QALY gains more conservative. The committee was presented with results from the original model undertaken for this guideline, which concluded that second-eye cataract surgery is likely to be cost effective in most cases even if it confers no immediate HRQoL gain (see chapter 6). This is because immediate surgery avoids future QALY losses and costs incurred by leaving the cataract(s) to progress until death. Compared with the first eye, the committee was mindful that there are slightly more scenarios in which HRQoL gain is necessary to produce an ICER lower than £20,000 / QALY; however, in common with the first eye, all these relate to people aged 90. In most cases, these scenarios also feature a high risk of visual loss, but even then only a ‘very small’ immediate HRQoL benefit is required to make surgery cost effective. Therefore, the committee agreed that immediate second-eye cataract surgery, without any requirement for acuity thresholds, would invariably be the optimal strategy as it saves future costs and QALY losses. The committee noted that the model results were on the whole very similar for first-operated eyes, and that it was common that in their own practice for first-eye patients to request second-eye surgery because they found the first-eye surgery to be beneficial. The original model was not designed to provide a dynamic simulation of these potential concerns. The committee discussed the likely resource and capacity impacts of recommending immediate referral, particularly the increased demand for surgery and associated pressures on capacity. The consensus of the group was that this would likely be a short-term increase in demand as those people with visual acuity below thresholds (in trusts where they currently apply) would move to waiting lists, but that after that initial increase there would be a return to a steady state. This is supported by the Royal College of Ophthalmology NOD studies which show that the modal acuity for first-eye patients is 6/6. Therefore, the committee considered that using the same criteria as recommended for first-eye surgery in Section 6 of the Guideline when deciding to offer second-eye surgery was logical and justified by these models. |
| Quality of evidence | The committee agreed that the evidence presented was robust, both in demonstrating the clear clinical benefits of second-eye surgery versus no second-eye surgery, and in demonstrating that there were no major differences in the long-term visual outcomes of same day or different day surgery in the groups recruited, but agreed that there were 2 major limitations in the evidence base. Firstly, the sample sizes were too small to pick up potential differences in rare but catastrophic complications, which are the main reason for concern with simultaneous surgery. Secondly, the populations in the trials were very carefully selected to only include those people with low risk of intra- or postoperative complications, and therefore no evidence was available on outcomes for people at higher risk, such as those with ocular comorbidities. Therefore, the committee decided it would only be appropriate to recommend simultaneous surgery as an option in the population covered by the trials, specifically those at low risk of intra- or postoperative complications. |
| Other considerations | The committee noted there were specific groups of people in which general anaesthesia may be necessary for cataract surgery (for example, people with cognitive impairment), and in whom general anaesthesia may be associated which increase risks of complications or distress. The committee agreed this represented an identifiable group of people in whom bilateral simultaneous surgery may be a relevant option, as it will mean the person only needs to undergo general anaesthesia once rather than twice, and that this population should be added to the ‘consider’ recommendation for bilateral simultaneous surgery. |
10.2.7. Recommendations
- 34.
Offer second-eye cataract surgery using the same criteria as for the first-eye surgery (see section 6 for referral for cataract surgery).
- 35.
Consider bilateral simultaneous cataract surgery for
- people who are at low risk of ocular complications during and after surgery or
- people who need to have general anaesthesia for cataract surgery but for whom general anaesthesia carries an increased risk of complications or distress.
- 36.
Discuss the potential risks and benefits of bilateral simultaneous cataract surgery with people, which should include:
- the potential immediate visual improvement in both eyes
- how it will not be possible to choose a different intraocular lens based on the outcome in the first eye
- the risk of complications in both eyes during and after surgery that could cause long-term visual impairment
- the likely need for additional support after the operation.
- Surgical timing and technique - Cataracts in adults: managementSurgical timing and technique - Cataracts in adults: management
- tdrd3 [Mastacembelus armatus]tdrd3 [Mastacembelus armatus]Gene ID:113138121Gene
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