Cataract Surgery in Cognitive Impairment: Navigating the Accessibility Challenge in European Healthcare

Abstract

This narrative review examines the challenges of providing cataract surgery to people living with cognitive impairment within European healthcare systems. It highlights the significant unmet need for improved ophthalmological management of this vulnerable population, given the established link between visual impairment, cognitive decline, and quality of life. While the benefits of cataract surgery in improving vision and cognition are well-documented, significant inconsistencies exist across European healthcare systems regarding protocols and access. The review examines the relationship between cognitive impairment and cataract surgery outcomes, identifies gaps in current practices, and proposes potential solutions to improve access and outcomes for this patient group, emphasizing the need for person-centered care, integrated pathways, and improved pre- and post-operative management. Ultimately, the authors advocate for a more coordinated and holistic approach involving ophthalmologists, geriatricians, and cognitive impairment specialists to ensure comprehensive care for this population.

Key Summary Points

Unmet need: Significant gaps exist in ophthalmological management for patients with cognitive impairment undergoing cataract surgery across European healthcare systems.

Visual impairment link: Visual impairment in cognitive impairment patients negatively impacts cognitive function and overall quality of life, highlighting the importance of cataract surgery.

Inconsistent access and protocols: European healthcare systems show inconsistencies in protocols and access to cataract surgery for people living with cognitive impairment.

Holistic, person-centered approach needed: A coordinated, person-centered approach is crucial, involving ophthalmologists, geriatricians, and cognitive impairment specialists for comprehensive pre- and post-operative care.

Improved pathways and management: The review advocates for the implementation of integrated care pathways and enhanced pre- and post-operative management to improve access to and outcomes for this vulnerable population.

Introduction

With the aging of the global population, the demand for eye health services is rising [1]. Along with uncorrected refractive errors, cataracts continue to be the leading cause of visual impairment and preventable blindness worldwide [1]. A significant global disparity exists in visual impairment and blindness, with over 80% of affected individuals residing in developing countries. Within this population, women and girls constitute 55% [2]. The association between visual impairment and diminished quality of life is well established [3, 4].

Cataracts are characterized by the clouding of the crystalline lens and age is the primary risk factor for cataracts [4]. However, other risk factors have been identified, such as certain systemic diseases, the intake of specific drugs, and exposure to sunlight [5–7]. The consequences of visual impairment and blindness are extensive. They include increased risks of falls, injuries, depression, cognitive impairment, mainly cognitive impairment, and mortality.

These findings are supported by a recent meta-analysis that demonstrated a statistically significant association between visual impairment and increased age-adjusted all-cause mortality across diverse settings and global populations [2]. The provision of high-quality cataract services is significantly challenged by the inequitable distribution of available resources, a problem particularly acute in developing and underdeveloped countries [8].

Conversely, prevalent mental health illnesses in adults include depressive disorders, anxiety disorders, and cognitive deterioration. These conditions can negatively affect quality of life [4]. Cognitive impairment—including Alzheimer's disease (AD), vascular cognitive impairment, AD with cerebrovascular disease, and cognitive impairment with Lewy bodies—is among the most common causes. These illnesses significantly impact memory, thinking, and daily life. They predominantly affect older adults but can also impact younger individuals [9]. The societal and economic burden of these diseases is considerable. They significantly affect disability rates among the elderly [9]. It is estimated that cognitive impairment may affect around 50 million people globally, and no curative treatment currently exists [10].

A recent meta-analysis from 17 European countries (n > 300,000 participants) reveals substantial heterogeneity in reported cognitive impairment care costs among different countries, ranging from €7938 in Eastern Europe and the Baltics to €73,712 in the United Kingdom (UK) [11]. This highlights the influence of regional healthcare systems and resource allocation on overall expenditure. A strong positive correlation was found between disease severity and overall cost. This effect was particularly pronounced for direct nonmedical and informal care components. Notably, institutionalized people incurred significantly higher costs compared to those receiving community-based care [11].

Cataracts and cognitive impairment are two prevalent conditions among older adults, often coexisting [12] and significantly impacting quality of life. Cataract surgery is commonly conducted on an outpatient basis, and patients generally experience excellent visual recovery [13]. It is one of the most successful ophthalmologic and non-ophthalmologic surgical interventions that exist [13]. Cataract surgery is cost-effective, yet excessive wait times pose a significant societal problem due to the considerable impact on individuals and society [14].

Extensive literature, including narrative reviews, systematic reviews, meta-analyses, and even guidelines, indicates an association between cataracts and cognitive impairment. It may offer the potential to alleviate, and possibly reverse, these conditions [4, 10, 15–32]. Meuleners et al. showed that after the first cataract surgery, a reduction in mental health contacts for depression and anxiety by 18.8% in the year after surgery [33]. Moreover, they also observed a 28% reduction in costs related to the decrease in the number of mental health service contacts [33]. Similarly, Wang et al., in a national cohort, observed that cataract surgery was associated with a 25% lower risk of depression compared to those who did not undergo the surgery [19]. Maharani et al. showed that cataract surgery was associated with a reduction in the rate of cognitive decline over 13 years of follow-up [34], and Lee et al. also showed that cataract extraction was significantly associated with a lower adjusted hazard ratio (HR) for cognitive impairment (HR, 0.71; 95% CI 0.62–0.83; P < 0.001) [10].

The significant improvements in vision, cognition, mood, and quality of life resulting from cataract surgery are significant in improving overall wellbeing. These improvements emphasize the necessity for coordinated care strategies. Such strategies should aim to address the high prevalence of cataracts among individuals with cognitive impairment. This is a particular challenge for healthcare systems and ophthalmological services. According to the evidence, suboptimal eye care and a high prevalence of visual impairment are significant problems among older institutionalized individuals with cognitive impairment [35].

Extensive research has demonstrated improved conditions and quality of life in cognitive impairment and cognitive impaired people following cataract surgery. However, a critical gap exists in the literature concerning the screening protocols and management strategies employed by healthcare systems for these individuals. This necessitates further investigation to address the following key questions:

1. What is the relationship between cognitive impairment and cataract surgery outcomes?

2. Do variations exist in European healthcare cataract surgery protocols for people living with cognitive impairment?

3. Which pre- and postoperative management protocols demonstrate optimal effectiveness for people living with cognitive impairment undergoing cataract surgery?

4. What barriers and potential solutions exist to enhance access to cataract surgery for people living with cognitive impairment?

This narrative review aims to address the shortcomings in the ophthalmological management practices for people living with cognitive impairment across Europe by analyzing practices within healthcare systems, identifying gaps in current healthcare approaches and potential areas for improvement. It also investigates unresolved issues through an assessment of relevant literature to determine the sufficiency of available data for informing their resolution and answering the research questions posed by the authors.

Methods

This article is based on previously conducted studies and does not contain any new studies with human participants or animals performed by any of the authors. A non-systematic literature search was performed in December 2024 using the following databases: The National Library of Medicine (PubMed), Web of Science (WOS), and EMBASE. The keywords used in the strategy search were (“cataract surgery” AND “cognitive impairment”). Furthermore, a snowball approach was used to identify additional relevant references. The inclusion criteria encompassed articles evaluating cataract surgery in relation to cognitive impairment and studies associated with the healthcare system treating these individuals in Europe. An additional search of studies including the term (“protocol” OR “guidelines”) was performed for each European country to find specific protocols in the management of patients with cataract and cognitive impairment. No restrictions were applied in terms of study design, with the only exclusion from the narrative review of non-English-written papers.

Alternatively, ophthalmologists from major European countries, who are key evidence leaders (KELs) and members of various committees within the European Society of Cataract and Refractive Surgery (ESCRS) specializing in cataracts and the anterior segment, have been contacted personally by e-mail by one of the author (JF), to gather information on whether there are currently established ophthalmological care protocols for this type of patient in their respective countries.

What Is the Relationship Between Cognitive Impairment and Cataract Surgery Outcomes?

A demonstrable relationship exists between cognitive decline and low vision, a correlation particularly evident in the context of cataracts, a condition whose incidence is rising with an aging global population. Moreover, although the prevalence of cognitive impairment is predominantly concentrated in the older adult population, early-onset cognitive impairment (EOD), characterized by onset before age 65, constitutes a substantial public health concern [36]. Global prevalence of EOD in the 30–64 age group is estimated at 3.9 million, with an annual incidence of 370,000 new cases, according to recent meta-analyses [37, 38]. Likewise, the incidence increased significantly with age, nearly 30-fold from the 30–34 to the 60–64 age group (0.17 vs. 5.14 per 100,000 person-years) [38]. It is expected to continue to increase, particularly in low-income countries and territories [36]. Therefore, the association of these two conditions will become increasingly relevant in our daily clinical practice.

What Is the Nature and Extent of the Relationship Between Cognitive Impairment and Cataract Surgery Outcomes?

There is now evidence suggesting that cataracts may increase the risk of cognitive decline, especially in older individuals [39]. Three primary theories may account for the connection between sensory impairments (such as vision and hearing loss) and cognitive functioning [34]. The first is the shared cause theory, which proposes that the decline in both sensory and cognitive abilities stems from common age-related factors, such as central nervous system degeneration [40]. The second is the domino effect theory, which suggests that sensory impairments can trigger a chain reaction impacting cognitive performance, potentially through neurobiological pathways or indirectly via reduced self-confidence, social withdrawal, or depressive symptoms [34]. The third hypothesis is that people with sensory disabilities are at a disadvantage in their performance on cognitive tests [34, 41].

The connection between cataract, Alzheimer’s disease-related cognitive impairment, and cataract surgery is particularly noteworthy. Multiple robust epidemiological studies have shown a significant link, reporting that cataract surgery is associated with a 30% decrease in cognitive impairment risk. For instance, the longitudinal Adult Changes in Thought (ACT) study, which followed over 3000 individuals aged 65 and older for a decade, demonstrated a substantially lower risk of developing cognitive impairment in those who underwent cataract surgery compared to their counterparts [10].

Further supporting this association, a 2023 meta-analysis of four cohort studies comprising 245,299 participants, which reported a significant protective effect of cataract surgery against cognitive impairment (OR: 0.77; 95% CI 0.66–0.89). While the overall effect was significant, there was even greater suggestion that this was for the reduction in risk of developing Alzheimer’s-type cognitive impairment specifically (OR: 0.60; 95% CI 0.35–1.02) [29]. The absence of a similar association with glaucoma surgery, a procedure that does not restore visual function, strongly suggests that visual restoration, rather than the surgical intervention per se, is the key mechanism driving the observed protective effect [10].

The sensory deprivation hypothesis offers a compelling explanation for the link between visual loss and cognitive impairment and is often considered the most plausible theory. By limiting environmental interaction, visual impairment may contribute to increased cognitive impairment risk via several mechanisms, such as increased social isolation, depression, decreased physical activity, reduced cognitive stimulation, and impaired cognitive reserve. A UK Biobank study found that moderate-to-severe visual impairment raises cognitive impairment risk 2.16 times compared to normal vision [42].

Recently, and interestingly, studies have suggested the existence of an ocular glymphatic system capable of transporting amyloid-beta (Aβ) from the brain to the eye via the optic nerve and aquaporin-4 channels, with subsequent drainage of retinal Aβ into lymphatic vessels. This intriguing pathway could help explain the elevated incidence of cataracts in AD, supporting the hypothesis that cognitive impairment may precede, rather than result from, ocular pathology [43]. The primary concern is conflicting evidence about beta-amyloid deposits in the crystalline lens. In 2003, Goldstein et al. [44] identified supranuclear cataracts and Aβ deposits in post-mortem lenses from AD patients, but later studies failed to replicate these results, casting doubt on the hypothesis [45].

These theories may be considered complementary, highlighting a potentially synergistic and self-perpetuating cycle. Indeed, the evidence suggests a bidirectional relationship between visual deprivation and neurodegeneration.

Cognitive resilience in cognitive impairment depends on preserving neurosensory function via interventions such as cognitive stimulation, hearing aids, and visual corrections [46, 47]. The enhanced cognition of cataract surgery in older adults is well documented, but the extent of these improvements is not uniform. Likewise, the risk of cataract complications seems to be similar between cognitive impairment and noncognitive impairment counterparts [46]. Numerous studies have noted a bidirectional relationship between visual impairment and cognitive decline [4, 10, 15, 48].

Visual impairment caused by cataracts can worsen cognitive impairment symptoms. This happens by increasing social isolation, reducing mobility, and impairing communication. Also, cognitive impairment can hinder the timely diagnosis and treatment of cataracts, as people living with cognitive impairment may struggle to report visual changes or attend regular eye examinations [4, 10, 15, 48]. Reduced visual acuity (VA) due to cataracts can impair performance on cognitive assessments that rely on visual processing. Conversely, the improved visual clarity achieved through cataract surgery often leads to better scores on these tests [10]. The visual impairment associated with cataracts may accelerate age-related neurodegenerative processes, potentially increasing the rate of cognitive decline. However, restoring visual function via cataract surgery could potentially slow or lessen this negative impact. It is also important to note that visual loss itself induces structural modifications in the visual cortex [10]. Clinically meaningful cognitive improvements after cataract surgery appear most pronounced in patients with mild cognitive impairment and VA between 20/40 and 20/70 (0.3–0.5 logMAR) [42, 49, 50]. Importantly, this highlights that the VA threshold for cognitive benefit seems less restrictive than those used for purely visual indications. In general, cataract extraction restores functional vision in most patients, including those with early dementia, with approximately four in five achieving 0.3 logMAR (20/40) VA and regaining independence in daily activities within a month [51]. Moreover, improvements extend beyond visual function, as cataract surgery demonstrably reduces fall risk, alleviates depressive symptoms, and decreases social isolation, especially with bilateral treatment [51, 52]. Therefore, and according to a recent meta-analysis, a potential association exists between cataract surgery and a reduced risk of cognitive impairment [53]. Impaired vision attributable to cataracts may represent a modifiable risk factor for cognitive decline [53].

Cataract surgery may be associated with a delay in cognitive impairment onset and improved cognitive performance in patients with cognitive impairment and pre-existing visual impairment [54]. Furthermore, post-surgical improvements in VA are often correlated with increased physical activity and enhanced quality of life in this patient population [54].

In addition, cataract surgery in patients with cognitive impairment carries a low risk of major surgical complications, including posterior capsule rupture and endophthalmitis, as has been described [46, 55]. The presence of cognitive impairment does not inherently elevate these risks, provided an experienced surgical team adapts its anesthesia and communication strategies [46, 55]. Furthermore, neurocognitive safety is a key consideration, and postoperative delirium is uncommon, with an estimated incidence of approximately 4% when regional anesthesia is used [56]. Strategies to further minimize the risk of delirium include caregiver presence and thoughtful medication selection [56]. Although it is outside the scope of the review, it is important to highlight that a potential association between cataract surgery and a reduction in depressive symptoms has been described [57]. The relationship between cognitive impairment, cataracts, and the benefits of cataract surgery is summarized in Table 1.

Table 1.

Summary of the most characteristic findings of the most relevant studies on cataracts and cognitive impairment

Authors, year	Study design	Population	Cataract patients sample size (n)	Cognitive assessment	Outcome goal	Cognitive benefits	CID patients preoperative CDVA logMAR ± SD	CID patients postoperative CDVA logMAR ± SD	Other
Kanda et al., 2024	Retrospective	Cataract	51 (67 eyes)	Cognitive impairment	To analyze the cataract pathway and surgical outcomes in patients with advanced cognitive impairment who lacked the capacity to consent for cataract surgery	VA/refraction and behavioral changes were not documented in several cases due to patient cooperation	Fingers count	0.2	–
Grove et al., 2024	Retrospective	Cataract	296 (507 eyes)	Cognitive impairment	Characterize cataract surgery in people with cognitive impairment	Not mentioned	0.454 ± 0.586	0.158 ± 0.405	Cataracts were more advanced in cognitive impairment
Ferguson et al., 2024	Prospective	Cataract	280,527	Cognitive impairment	Evaluate potentially causal associations between visual acuity, eye conditions (specifically cataracts and myopia), neuroimaging outcomes	Cognitive impairments were identified in 7676 patients during the follow-up Cataracts were associated with all causes of cognitive impairment	–	–	Cataracts were associated with smaller total gray matter volume, smaller lateral occipital volume, and greater white matter hyperintensity volume
Joo et al., 2024	Retrospective	Cataract	4384 cataract surgery vs. 4384 control	Cognitive function	To evaluate cognitive function before and after cataract surgery and compare with a non-surgery group	No differences in the amount of cognitive change before versus after 1 year of surgery	–	–	–
Yoshida et al., 2023	Prospective	Patients > 75-year-old, cataract surgery	88 patients	Cognitive impairment and MCI	Evaluate the impact of cataract surgery on MCI and cognitive impairment	Cataract surgery significantly increases cognitive test scores in older patients with MCI (more than in cognitive impairment)	CID 0.304 ± 0.50 MCI 0.106 ± 0.27	CID 0.035 ± 0.20 MCI − 0.051 ± 0.08	–
Lee et al., 2023	Retrospective	Cataract	300,327	Patients without cognitive impairment	Compare the risk of cognitive impairment between cataract surgery and no intervention	The cataract surgery group showed a marginally significant difference in cognitive impairment risk	–	–	–
Ma et al., 2023	Prospective	Cataract	4281 patients	Cognitive impairment	Explore the associations of cataract and cataract surgery with the risk of cognitive impairment	Lower incidence of cognitive impairment in the cataract group	–	–	36.8% decreased all causes of cognitive impairment
Verdina, 2022	Prospective	Cataract in elderly people > 85 years old	78 patients	Cognitive function	To evaluate the impact of cataract surgery on cognitive function in very elderly patients (≥ 85 years) vs. ≥ 65 < 85 years	Cataract surgery in very elderly patients seems to offer a greater improvement in cognitive function and QoL	–	–	–
Lee et al., 2022	Prospective	Cataract	3038	Cognitive impairment	To determine whether cataract extraction is associated with a reduced risk of cognitive impairment among older adults	Evaluation of the probability of cognitive impairment risk decreased after cataract surgery Reduced risk of cognitive impairment vs. no intervention	–	–	Lower risk was stronger during the first 5 years following cataract surgery
Hokkinen et al., 2022	Retrospective	Cataract	25,763 cataract surgery AD vs. 26,254 normal	AD	Evaluate the rate of cataract surgery in patients with and without AD	There is a decrease in the rate of AD surgeries vs. people without AD	–	–	–
Ma et al., 2022	Prospective	Cataract	3226 cognitive impairment; non-surgical group 8970 people surgical group 4281	Cognitive impairment	Explore the associations of cataract and cataract surgery with the risk of cognitive impairment	Cataract patients who did not receive surgical treatment had an increased risk of cognitive impairment	–	–	Cataract surgery could reverse the risk of cognitive impairment
Pershing et al., 2020	Retrospective	US Medicare beneficiaries > 65 years old	339,671 cognitive impairment vs. 4,111,529 normal	Cognitive impairment	Examine the relationship between cognitive impairment status and receipt of eye care	People diagnosed with cognitive impairment are less likely to receive eye care than those without a diagnosis	–	–	–
Stagg et al., 2019	Retrospective	Cataract	2021	Possible and probable CID	Community-dwelling Medicare beneficiaries with CID are less likely to receive cataract surgery than those with normal cognition	Participants with possible and probable CID were significantly less likely to receive cataract surgery than those with normal cognition after adjustment for patient factors	–	–	–
Pershing et al., 2019	Retrospective	Cataract	1,125,387	Cognitive impairment	Evaluate the rate of cataract surgery in patients with and without cognitive impairment	Cognitive impairments are less likely to undergo cataract surgery than those without cognitive impairment	–	–	Patients with cognitive impairment were 13% less likely to undergo cataract surgery on their second eye than patients without cognitive impairment
Pershing et al., 2019	Retrospective	Cataract	23,331 cognitive impairment vs. 457,128 normal	Cognitive impairment	Evaluate cataract surgery complexity and complications in patients with and without cognitive impairment	No differences regarding complications, higher-acuity setting, advanced anesthesia care, or postoperative hospitalization	–	–	–
Maharani et al., 2018	Retrospective	Cataract	2068 people	Cognition	Assess trajectories of cognitive decline before and after cataract surgery and between the no-cataract surgery group	Memory improved in cataract surgery	–	–	Decline of episodic memory scores was slower after cataract surgery than before cataract surgery
Miyata et al., 2018	Cross-sectional	Cataract	668	Cognitive impairment and mild cognitive impairment (MCI)	Evaluate the association between prior cataract surgery and cognitive function in an elderly cohort	The odds ratio for MCI was significantly lower in the prior cataract surgery group than in the no-cataract surgery group	–	CID 0.013 ± 0.16 MCI − 0.021 ± 0.14	–
Kheirkhah et al., 2018	Prospective	Cataract	196 patients	Cognitive impairment and depression	Compare pre-operative and postoperative depressive symptoms and cognitive impairments of patients who underwent cataract surgery	Reduced depressive symptoms. Positive effect on the cognitive status	0.113 ± 0.083	0.885 ± 0.196	Improved in Mini-Mental State Examination (MMSE)
Bowen et al., 2016	Cross sectional	Patients 60–89 years old	708 people	Cognitive impairment	Determine the prevalence of cognitive impairment and cataract	Cataract is associated with cognitive impairment	–	–	–
Jefferis et al., 2015	Prospective	Patients 75 years or older with bilateral cataracts	91 patients (46 normal cognition) (45 impaired cognition)	Cognitive impairment	Evaluate the impact of impaired cognition on visual outcomes 1 year following cataract surgery	Patients with impaired cognition benefit from cataract surgery	0.18 ± 0.14	0.06 ± 0.11	–
Yu et al., 2015	Retrospective	Cataract	113,123 patients	Cognitive impairment	Determine the association of cataract surgery with subsequent development of cognitive impairment in older adults with cataract	Decreased risk of cognitive impairment	–	–	Receiving cataract surgery within 365 days had the lowest HR of cognitive impairment amongst all groups
Goldacre et al., 2015	Retrospective	Cataract	793,738	Cognitive impairment	Determine whether cognitive impairment affects an individual’s chances of receiving treatment for cataract	Treatment rates for cataract were significantly lower in the cognitive impairment cohort than in the reference cohort	–	–
Jefferis et al., 2013	Cross-sectional	Patients > 85 years	839 people	Mental status	Explore the association between cognition and cataract. Evaluate Mini-Mental State Examination (sMMSE) score & blind version of the MMSE (MMblind)	History of previous cataract surgery scored better on the sMMSE (and the MMblind) than those without cataract but not significantly differently from those with untreated cataract	–	–	Glaucoma is also associated to low sMMSE score
Ishii et al., 2008	Retrospective	Cataract	88 patients	Elderly people	Assess vision-related QOL, cognitive function, and depressive mental status in elderly patients. Cognitive impairment and depression were assessed by interviewing subjects using MMSE and the Beck Depression Inventory (BDI)	Improved the QOL, MMSE, and BDI	0.46 ± 0.34	–	Cognitive impairment improved in parallel with the improvement in vision-related QOL
Micthell et al., 1997	Cross-sectional	Cataract	People in nursing home residency, 128 people (88 with cognitive impairment)	Cognitive impairment	Assess the prevalence and causes of visual impairment	Cataracts are less treated in nursing homes	–	–
Marx et al., 1995	Prospective	Cataract	People in nursing home residency, 19 cataract surgery vs. 22 no surgery	Cognitive impairment	Explore the associations of cataract and cataract surgery and cognitive impairment	Non-surgery groups were significantly more cognitively impaired	1.0	0.3	Non-surgery group has more activities impaired daily living
Fagerstrom, 1992	Prospective	Cataract	100	Normal	Correlations of memory and learning with vision in aged patients before and after cataract surgery	Memory and VA improved	–	–

MCI mild cognitive impairment, QOL quality of life, CID cognitive impairment and cognitive impairment, AD Alzheimer disease, CDVA Corrected Distance Visual Acuity

Do Variations in Healthcare Systems’ Cataract Surgery Protocols Exist Based on Patient Comorbidities, Including Cognitive Impairment? What Specific Pre- and Postoperative Management Protocols Are Most Effective for People Living with Cognitive Impairment Undergoing Cataract Surgery?

Analysis of published literature and healthcare system documentation demonstrates a significant lack of standardization in European cataract surgery protocols. Despite the growing prevalence of cognitive impairment and its documented impact on cataract surgery outcomes, our research of the published literature, European healthcare systems, and leading indicates a notable deficiency: the limited adaptation of existing cataract surgery protocols to address the specific needs and challenges presented by individuals with cognitive impairment, with VA often remaining the predominant inclusion criteria and few are adapted to particular conditions that these patients may present.

For example, in Denmark, cataract surgery decisions are based on a combined assessment of VA, objective findings, and patient-reported symptoms [58, 59]. In Finland, patients are referred to an ophthalmologist for diagnosis; surgery is indicated if daily living is impaired and best-corrected visual acuity (BCVA) is ≤ 0.5, or ≤ 0.3 in the worse eye [60].

The main indication of cataract surgery in Germany is marked worsening of vision and/or sensitivity to glare [61, 62]. In Hungary, early cataract surgery is recommended, especially when VA is less than 0.5 logMAR, reflecting the growing need for improved vision among patients [63]. In Sweden, patients with lower VA are given priority [64]. Some countries, such as Spain and Sweden, employ a VA criterion of 0.4 or 0.3 logMAR for cataract surgery consideration [64, 65]. However, in Spain in exceptional cases, quality of life questionnaires such as VF-14 are used to justify cataract surgery [65]. The most recent Spanish national plan for the management of AD and other cognitive impairments does not address ophthalmological care, and specifically lacks any guidance on cataract surgery [66].

Furthermore, it is crucial to consider that subjective measurements, such as VA and contrast sensitivity, can pose significant challenges in this population, especially when individuals are unable to effectively respond during tests that utilize symbols. This can lead to misinterpretations, compromising the results and, consequently, the ophthalmic treatment [67]. While recent ESCRS guidelines highlight the positive impact of cataract surgery on cognitive and mental wellbeing, and support considering cataract extraction in patients with an elevated risk of cognitive impairment and vision loss, the guidance regarding decision-making for individuals with pre-existing mental health conditions (such as cognitive impairment or depression) remains limited. The guidelines, therefore, fall short of providing a comprehensive protocol for the integrated management of this complex patient population [32].

Regarding the determination of surgical candidacy based on cataract severity, current practice typically adheres to VA thresholds outlined in national protocols. These thresholds, however, may pose a barrier for patients with advanced cognitive impairment, as we mentioned. Therefore, a simply slit-lamp examination to assess cataract maturity may, therefore, aid the ophthalmologist in the surgical decision-making process along with their caregivers.

Moreover, several studies have demonstrated that people living with cognitive impairment, especially in advanced stages, should be evaluated with alternative methods for assessing vision [67–70]. Different measurement techniques from validated VA charts have been employed, including Teller Cards, Patty Pictures, and Tumbling E’s [67, 70]. It has been demonstrated that VA measurement is needed for disease monitoring and treatment, as well as the determination of vision loss and efficiently managing the residual vision to improve their quality of life [67, 68, 71]. Therefore, health systems should adopt these alternative methods of measuring VA to ensure proper ophthalmological care for these patients.

While the optimal timing of cataract extraction in patients with cognitive impairment warrants further investigation, we acknowledge that intervening at less advanced stages of cataract presents a multi-faceted consideration. Studies suggest that cataract extraction performed early in the course of visual decline (i.e., before severe visual limitation) may be associated with the most substantial cognitive benefits for patients with mild cognitive impairment (MCI), including a reported 23–30% reduction in dementia risk and a mean gain of 1.5 points on the Mini-Mental State Examination (MMSE) [24]. While the magnitude of cognitive improvement appears diminished in patients with established dementia, cataract surgery remains clinically significant for enhancing quality of life and mitigating fall risk [72, 73]. The case for early intervention is further strengthened by the potentially less complex postoperative management, the well-established cost-effectiveness and safety of cataract surgery, the potential for cognitive improvements alongside visual benefits, and the expectation of excellent visual rehabilitation and enhanced quality of vision. Accordingly, some authors’ recommendations increasingly emphasize a shift away from rigid VA thresholds, instead advocating for expedited surgical intervention "as soon as possible" following confirmation of surgical indication; [74] this approach may be particularly advantageous among individuals with MCI for the reasons outlined above. Moreover, although a definitive cognitive threshold for withholding cataract surgery remains undefined, the available evidence suggests that meaningful cognitive improvements are rarely observed when MMSE scores fall below 23, or when patients reach a Global Deterioration Scale (GDS) stage of 6–7 and exhibit significant frailty [24, 72]. This highlights the potential limitations of cognitive benefit in more advanced stages of cognitive decline. Accordingly, rigorous research is urgently needed to definitively establish the optimal timing of cataract surgery in patients with cognitive impairment.

To the authors’ knowledge and based on a comprehensive review of relevant scientific literature and protocols from various European healthcare systems, no established cataract surgery protocols specifically address the needs of people living with cognitive impairment. Recent research has demonstrated significant improvements in disease course and quality of life following cataract surgery in this population. It is also important to note that, although not without bias—since personal e-mail communication may lack rigorous scientific standards—none of the KELs indicated the presence of a specific ophthalmological care protocol for people living with cognitive impairment and other cognitive disorders in their countries. Nevertheless, all emphasized that establishing a solid foundation for the development of such protocols is a priority for the scientific community.

What Are the Challenges and Potential Solutions for Enhancing Access to Cataract Surgery for People Living with Cognitive Impairment Within European Health Systems?

The available evidence points to a challenge in healthcare access for certain vulnerable populations, notably older adults with cognitive impairment who may be experiencing concurrent cognitive impairment and cataract. We have demonstrated the requirement for well-designed cognitive impairment care pathways to improve access to specialist services and ensure continuity of care [9]. In a recent scoping review, which investigated gaps and priorities in European cognitive impairment care, utilizing meta-ethnography and stakeholder consultation, the authors identified several key shortcomings: fragmented, non-person-centered care pathways; a care culture prioritizing efficiency over individual needs; limited professional knowledge skills; poor communication, information sharing, and ineffective healthcare policies [9]. These gaps contribute to unmet needs and poor care experiences for individuals with cognitive impairment [9]. The study highlights the need for person-centered care, integrated care pathways, and substantial healthcare workforce development [9]. Person-centered care emphasizes individual needs and preferences, while integrated pathways aim for seamless service delivery [9].

Pre-surgical cognitive assessment, depression screening, and evaluation of the patient’s psychological preparedness for surgery are crucial [4]. The impact of visual loss resulting from cataracts on cognitive decline underscores the importance of timely surgical intervention to alleviate visual impairment and mitigate accelerated cognitive deterioration [4]. However, enhanced diagnostic vision testing is needed within nursing homes, with a particular focus on facilities providing cognitive impairment care. A recent scoping review revealed a limited availability of suitable screening tools for nurses in long-term care settings, thereby highlighting the necessity for further research [75].

Despite the clear benefits, several barriers still limit access to ophthalmological care for people living with cognitive impairment. People living with cognitive impairment may have difficulty understanding the need for treatment or complying with pre- and post-operative care protocols [48]. Family members and caregivers often face logistical and emotional challenges in coordinating ophthalmic care [48]. A lack of integration between ophthalmological and geriatric care can delay diagnosis and treatment [48]. People living with cognitive impairment received significantly less eye care and cataract surgery than a non-cognitive impairment cohort. This disparity was even greater among older adults, women, and those in rural areas or with multiple comorbidities [76].

According to a large cohort, a statistically significant association exists between a recent diagnosis of AD and a reduced likelihood of undergoing cataract surgery compared to non-AD patients [77]. Recommendations to improve care for this population should include optimizing care for people living with cognitive impairment, which requires a collaborative and holistic approach. Establishing integrated care pathways involving ophthalmologists, geriatricians, and cognitive impairment specialists could ensure comprehensive assessment and treatment of visual and cognitive problems. Based on current evidence, it seems to make sense to incorporate regular ophthalmologic assessments into routine cognitive impairment care plans to promptly address the visual impairments of these patients. To do so, it is essential to equip caregivers with the knowledge and resources necessary to carry out this task.

Surgical planning and postoperative care should be tailored to the individual needs and abilities of people living with cognitive impairment and other cognitive impairments. Adapting surgical techniques as best as possible and postoperative medication regimens, such as offering simplified medication schedules and using sedation options when appropriate, could minimize stress and maximize positive outcomes. This personalized approach is tailored to the specific challenges presented by cognitive impairment. Raising public awareness about the vital link between eye health and cognitive wellbeing is essential. Public health initiatives should emphasize the importance of timely eye care to maintain cognitive health. Targeted educational campaigns can help reduce the stigma surrounding cognitive impairment, promote early diagnosis, and facilitate access to appropriate eye care for this population. For older individuals, the optimal timing for cataract surgery may be during the MCI stage. It is preferable to perform the surgery at this stage rather than at later stages characterized by more pronounced cognitive deficits [24].

Therefore, there is still much to explore and adapt if we want to improve the ophthalmological care of people living with cognitive impairment, especially in the absence of standardized protocols that guarantee efficient screening and detailed care and attention for these patients. Moreover, many questions remain unanswered, such as when is the optimal stage of cognitive impairment at which to perform cataract surgery, which kind of anesthesia is the most appropriate for them [78, 79], which intraocular lens (IOL) is best for these patients, those providing a full range of field or those offering a partial range [80], or even it is better to perform an immediate or delayed sequential bilateral cataract surgery [81]. These and related questions warrant further investigation via rigorously designed studies, such as randomized controlled trials (RCTs), although the inherent challenges of conducting such trials in this patient population are duly acknowledged. One review has recently raised part of these dilemmas [73, 82]. Furthermore, determining the best ophthalmological approach to guide cataract surgery decisions in patients with cognitive impairment requires further investigation. This requires clarification on the optimal use of VA assessment, and whether other parameters are needed for a comprehensive evaluation. While this review provides valuable insights into cataract management in individuals with age-related cognitive impairments, we acknowledge that other pathologies, such as developmental disabilities, can also present with neurological alterations that may impact surgical outcomes. In this line, cataracts in individuals with Down syndrome (DS) warrant distinct consideration due to the heightened risk of early-onset Alzheimer’s disease-related cognitive decline in this population, creating a dual challenge [83–85]. Neuropathological studies indicate that Beta-amyloid, a protein associated with AD, may also play a role in cataract formation in individuals with DS [86]. The potential for early intervention in ocular conditions to influence cognitive outcomes underscores the critical importance of timely and proactive ophthalmic management in this patient population.

However, this and other conditions are beyond the current scope of this work, and they represent an area that requires further investigation. Indeed, establishing specific guidelines and protocols for managing cataract surgery in these diverse patient populations is vital to ensure optimal care and outcomes. The failure to address these crucial questions is a significant gap in current knowledge. Immediate and concerted efforts by the scientific community and healthcare systems are necessary to ensure patients receive optimal care.

Our review highlights the importance of ophthalmologists being aware of subtle cognitive changes that may indicate the need for expedited cataract surgery. In non-neurological settings, the recognition of these prodromal symptoms of cognitive decline should be primarily guided by patient-reported concerns and family member observations, rather than relying solely on objective cognitive testing. While there are validated questionnaires designed to assess subjective memory complaints [87], such information is often obtained through standard patient history-taking with input from relatives. Additionally, brief cognitive screening tools—such as the Mini-Mental Test [88] or the Photo Test [89]—may be employed within the ophthalmology setting when cognitive impairment is suspected. Ultimately, we propose that the effective management of these complex cases hinges upon robust interdisciplinary integration and communication between ophthalmology, primary care, geriatrics, and neurology.

In conclusion, this review shows that cataract management in people living with cognitive impairment, implemented even in the preclinical phases, offers substantial benefits extending beyond VA recovery. Evidence indicates a significant improvement in overall quality of life and a potential deceleration of cognitive decline. Furthermore, it appears that they do not exhibit a higher risk of surgical complications, require advanced anesthesia care, or experience prolonged postoperative hospitalization. However, the critical lack of prioritization of ophthalmological access for people living with cognitive impairment within existing healthcare systems underlines the urgent need for integrated programs across healthcare to improve their situation. A coordinated multidisciplinary strategy is essential. This strategy should encompass targeted screening programs, particularly within long-term care facilities. Additionally, there should be enhanced public awareness and robust caregiver support. Further research is also needed to develop multidisciplinary protocols and standardized clinical guidelines, based on the best available evidence, involving various specialties to improve the overall ophthalmological care of these patients. These measures are imperative to address the disparity in ophthalmological care experienced by this vulnerable patient population.

Author Contributions

All authors contributed to the study’s conception and design. Material preparation, data collection, and analysis were carried out by Carlos Rocha-de-Lossada and Noemí Burguera. Carlos Rocha-de-Lossada, Noemí Burguera, and H. Burkhard Dick drafted the initial manuscript, while Joaquín Fernández, Filomena Ribeiro, Paul Ursell and Pedro J. Serrano reviewed and refined subsequent versions. All authors read and approved the final manuscript.

Funding

No funding or sponsorship was received for this study or publication of this article.

Data Availability

Data sharing is not applicable to this article as no datasets were generated or analyzed during the current study.

Declarations

Conflict of Interest

Carlos Rocha-de-Lossada, Noemí Burguera, Joaquín Fernández, Filomena Ribeiro, Paul Ursell, Pedro J. Serrano, and H. Burkhard Dick have no competing interests.

Ethical Approval

This article is based on previously conducted studies and does not contain any new studies with human participants or animals performed by any of the authors.