Prevalence of visual impairment, ocular trauma, and ocular disorders among conflict-affected and displaced populations: a systematic review and meta-analysis

Abstract

Introduction

Conflicts and forced displacement often leave behind severe health consequences, including a significant burden of eye diseases and injuries. Refugees and internally displaced persons (IDPs) face increased risk due to limited access to eye care services and exposure to trauma. This systematic review and meta-analysis aimed to assess the prevalence and outcomes of ocular injuries and diseases in displaced and conflict-affected populations.

Methods

A comprehensive literature search was conducted across PubMed, Google Scholar, and ScienceDirect databases for studies published between January 2000 and April 2025. Nineteen studies met the inclusion criteria. Data extraction, risk of bias assessment using the Newcastle–Ottawa Scale, and meta-analyses were conducted following PRISMA guidelines. Prevalence estimates were pooled using a random-effects model, and subgroup analyses were performed by study design.

Results

The review included 19 studies from 14 countries, with a combined sample of 59,728 participants. Ophthalmic trauma had a pooled prevalence of 22.7%, while phthisis bulbi, a severe outcome of eye trauma, had a prevalence of 3.6%. Among non-traumatic conditions, cataract was the most frequently reported, with a pooled prevalence of 5.5%, followed by glaucoma (1.7%) and refractive errors (26.0%). Blindness affected 2.5% of the studied populations, while severe visual impairment had a pooled prevalence of 7.3%. Reliable pooled estimates for mild and moderate visual impairment were heterogeneous and variably reported, and therefore a single consolidated range (e.g., 7.3%–19.4%) may overstate precision and should be interpreted cautiously.

Conclusion

Displaced and conflict-affected populations bear a substantial burden of both traumatic and non-traumatic eye conditions, often worsened by limited access to timely diagnosis and treatment. The findings highlight the urgent need for integrating eye health services into humanitarian response plans, with a focus on early detection, rehabilitation, and continuity of care to reduce preventable vision loss.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13031-026-00765-6.

Introduction

The World Health Organization’s (WHO) World Report on Vision states that blindness or vision impairment impact 2.2 billion people [1]. The global community including WHO member states and international donors have been calling for reducing rates of blindness and visual impairment by 25% [1, 2]. This can be achieved by implementing the universal health coverage principles through provision of timely high quality and affordable ophthalmic health services [3]. Achieving this target requires prioritization of underserved and vulnerable populations, including refugees and internally displaced people (IDPs).

Armed conflicts have led to health system damage and humanitarian crisis, which have led to displacement movements of millions of forcedly displaced populations [4]. As a result of that, the health status of refugees and IDPs deteriorate due to infectious or non-communicable diseases including ocular infections, injuries and other chronic diseases [5]. In this review, ocular injury refers to traumatic insults to the eye, including open- and closed-globe injuries. There are different reasons for eye injuries, and the most frequent types include mechanical, chemical and heat injuries [6]. These injuries can occur due to radiation, blast injuries, laser and stress-induced trauma. As a result, different ocular structure can be damaged [6]. For example, researchers reported numerous cases of eyeball perforation, lens dislocation, corneal rupture, burns to superficial structures like eyelids, conjunctiva and cornea [7]. In addition, radiation can damage deeper structures like retina as a result of a nuclear blast [8].

Concerning ocular disorders, they encompass non-traumatic ophthalmic conditions such as refractive errors, glaucoma, and corneal or retinal disorders, as defined by the included studies. Some literature reported cataract as the leading cause of visual impairment among refugee population. This may be due to late management of cataract [9]. In addition, post-surgical astigmatism has been reported to be higher in Syrian refugees [10]. Kaphle et al. reported that refractive error and presbyopia were the most common ocular morbidities among refugees in Malawi [11].

Despite this evidence, access to ophthalmic health services in refugee camps and conflict-affected settings remains limited, resulting in fragmented data and under-reporting of ocular injuries and disorders. Consequently, the true prevalence and clinical outcomes of these conditions are not well characterized.

Understanding the epidemiology and health consequences of these conditions is essential to inform effective health interventions, optimize resource allocation, and guide humanitarian response efforts aimed at preserving vision and improving overall wellbeing [12]. Therefore, this systematic review aims to synthesize existing evidence on the prevalence and clinical outcomes of ocular injuries and eye diseases among populations living in conflict-affected and displacement settings, thereby addressing this critical knowledge gap and informing future public health strategies.

Methodology

Protocol and registration

This systematic review and meta-analysis were conducted in accordance with Cochrane guidelines and followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) checklist. The protocol was registered in Open Science Framework (OSF).

Eligibility criteria

Studies were eligible for inclusion if they reported on the prevalence or outcomes of ocular injuries or diseases among populations affected by armed conflict or forced displacement. Eligible research designs included cross-sectional studies, case–control studies, cohort studies, and randomized or non-randomized clinical trials. Populations of interest encompassed refugees, internally displaced persons (IDPs), asylum seekers, and civilians residing in conflict or post-conflict settings, including those living in refugee camps, detention centers, or urban displacement contexts. Only studies published in English between January 2000 and April 2025 were included in the review.

Studies were excluded if they did not report specific ocular outcomes or prevalence data, or if their populations consisted solely of voluntary immigrants or economic migrants not displaced by conflict or humanitarian crises. Editorials, commentaries, letters, and conference abstracts without primary data were excluded. Studies focusing exclusively on military personnel were also excluded unless they concurrently included data on the general civilian population.

Information sources and search strategy

A total of 4204 records were identified through database searches, including 2140 from Google Scholar, 1999 from ScienceDirect, and 65 from PubMed. After removing duplicates (144 studies), 4060 records were screened based on titles and abstracts. Of these, 4029 were excluded for not meeting the inclusion criteria. The remaining 31 full-text articles were retrieved and assessed for eligibility. Twelve studies were excluded at this stage due to reporting on irrelevant populations or lacking outcome data related to ocular diseases or injuries. Ultimately, 19 studies met the inclusion criteria and were included in the meta-analysis. The full study selection process is illustrated in the PRISMA flow diagram (Fig. 1). The search strategy employed is shown in Table 1.

Fig. 1.

PRISMA flow diagram illustrating the study selection process for the systematic review and meta-analysis. A total of 4,204 records were identified through database searches

Table 1.

Summary of search strategies and number of records identified across databases

Database	Search strategy used	Number of records identified
Google scholar	("eye disease" OR "ocular disease") AND ("conflict zone" OR "war zone" OR "forced displacement" OR "refugee") AND ("prevalence" OR "outcome" OR "complication")	800
Google scholar	("ocular injury" OR "eye trauma" OR "eye injury" OR "ocular trauma") AND ("eye disease" OR "ocular disease") AND ("conflict zone" OR "war zone" OR "displacement" OR "refugee" OR "humanitarian crisis") AND (prevalence OR incidence OR outcomes OR complications)	1340
PubMed	("eye injury" OR "ocular trauma") AND ("conflict" OR "war" OR "displacement" OR refugee) AND (prevalence OR outcomes OR incidence)	65
Sciencedirect	("eye injury" OR "ocular trauma") AND ("conflict" OR "war" OR "displacement" OR refugee) AND (prevalence OR outcomes OR incidence)	1999
Total before removing duplicates		4204
Total after removing duplicates		4060

Study selection

Records retrieved from the databases were imported into a reference manager software (Rayyan), and duplicates were removed [13]. The final list of records was exported into a Google spreadsheet for screening. A.A, A.G.A, R.M.A.J, A.O.A, S.A conducted the screening of titles and abstracts. Authors worked independently in this stage. After that, five authors conducted full-text screening. Screeners continued to work independently during this round, without discussing their decisions to avoid bias. The lead researcher verified the list of included studies from the previous rounds, ensuring consistency and confirming eligibility. Also, the lead researcher resolved discrepancies and made the final decision.

Data collection process

A standardized data extraction form was developed to collect key variables from each included study. Extracted data included study metadata (authors, year, country), study design, sample size, population characteristics (age, sex, displacement status), ocular conditions assessed (e.g., trauma, cataract, glaucoma), setting (e.g., refugee camps, hospitals), and outcome-specific prevalence rates. Data extraction was independently conducted a total of five authors, with discrepancies resolved through consensus discussion or adjudication by a senior reviewer to ensure accuracy and consistency.

Risk of bias assessment

The methodological quality of the included studies was assessed using the Newcastle–Ottawa Scale (NOS), which evaluates non-randomised studies across three domains: selection of study groups, comparability of groups, and ascertainment of either the exposure or outcome [14]. Three authors: F.E.A.M, A.A, S.A conducted the risk of bias assessment. Each study was independently reviewed and scored by two authors, with a maximum score of 9 indicating the lowest risk of bias. Following discussion, authors discussed the scoring and finalized the risk bias assessment. NOS assessments were used to categorize studies as having low risk of bias (≥ 7 points), moderate risk (4–6 points), or high risk (≤ 3 points). This evaluation informed sensitivity analyses and interpretation of findings, particularly regarding heterogeneity across study designs and populations.

Data analysis

Data analysis was performed using Comprehensive Meta Analysis (CMA) version 3 [15]. We conducted a meta-analysis to estimate the pooled prevalence of ocular conditions in conflict-affected and displaced populations. Prevalence estimates and 95% confidence intervals (CIs) were extracted or calculated for each condition. Data were synthesized using the DerSimonian and Laird random-effects model to account for anticipated between-study heterogeneity due to differences in study design, populations, and diagnostic criteria.

For the outcome, heterogeneity was assessed using the I² statistic to quantify variability not attributable to chance. I² values of 25%, 50%, and 75% were interpreted as low, moderate, and high heterogeneity,

Where appropriate, subgroup analyses were performed based on study design (cross-sectional, retrospective, mixed-method, cohort, or case series) to examine methodological impacts on reported prevalence. Subgroup differences were assessed using the Q statistic for heterogeneity between groups.

Forest plots were redesigned using Python (version 3.10) with the Matplotlib (v3.8) and Pandas (v2.1) libraries to generate publication-quality prevalence forest plots.

Results

Study characteristics

A total of 19 studies conducted across 14 countries were included, representing a combined sample size of 59,728 individuals. Sample sizes ranged from 17 to 48,105 participants. Eleven studies reported mean participant ages. Age ranged from 8 years to 65.4 years. Nine studies explicitly reported ocular trauma as the primary ocular condition assessed. Other ocular conditions reported included cataract, and refractive errors. Studies were conducted in a range of settings, including refugee camps, outpatient clinics, hospitals, and offshore detention centers. The majority focused on refugees from the Syrian civil war and the Rohingya crisis (Table 2).

Table 2.

Characteristics of studies reporting ocular injuries among displaced or conflict-affected populations

Study ID	Study design	Setting	Conflict/Displacement status	Males	Females	Total Number of cases	Age (mean)	Inclusion criteria	Exclusion criteria
[24]	Clinic-based cohort study with structured outreach	Rohingya refugee camps, Cox’s Bazar, Bangladesh	Displaced Rohingya and host community	25,138	22,967	48,105	—	Screened Rohingya and host community, presented voluntarily	—
[17]	Cross-sectional study	Philadelphia, USA	Resettled Syrian refugees	8	9	17	42.3	Recently resettled Syrian refugees	—
[19]	Cross-sectional study	Toronto, Canada	Resettled Syrian refugees	117	131	248	36	Adults aged 18 +	—
[19]	Cross-sectional study	Toronto & nearby (Canada)	Resettled Syrian pediatric refugees	131	143	274	8	≤ 18 yrs, Syrian, resettled with guardian	—
[27]	Cross-sectional study	Mankien district, Southern Sudan	Post-conflict	158	245	403	23.9	Individuals ≥ 5 years from selected households	Children < 5, absent individuals, full-household unavailability, residents of 12 insecure villages
[5]	Cross-sectional study	Refugee camps, Ethiopia	Refugees	517	537	1,054	—	—	—
[20]	Cross-sectional study	IDP camps, Khartoum, Sudan	Internally displaced persons	449	467	916	—	Not reported	Not reported
[21]	Retrospective cohort study	Outpatient clinic, Turkey	Syrian refugees	77	176	253	46.4 ± 20.8	Syrian refugees with visual impairment	Not reported
[25]	Cross-sectional study	Western Province, Rwanda	Post-conflict	1,025	1,181	2,206	—	Not reported	Not reported
[9]	mixed-method study	Offshore detention centers, Nauru and Manus Island	Displaced/refugees	67	13	80	34.1 ± 10.7	—	—
[22]	Retrospective cohort study	CMCH, Bangladesh	Rohingya refugees	122	85	207	21.31 ± 15.63	Admitted Rohingya refugees via Outpatient/Emergency Depts at CMCH	Referred from other departments
[26]	Cross-sectional study	18/25 refugee camps, Uganda	Refugees	455	245	700	N/A	Eye care seekers in 18 of 25 refugee camps	Non-reporting individuals or from excluded camps
[3]	Cross-sectional study	Cox’s Bazar, Bangladesh	Rohingya refugees ≥ 50 yrs	1,718	1,911	3,629	—	RAAB-selected individuals ≥ 50 yrs; willing to undergo eye exams	< 50 yrs, unavailable, refused, or unmeasurable acuity
[11]	Cross-sectional study	Dzaleka Camp, Malawi	Refugees from DRC, Rwanda, Burundi, Somalia	348	287	635	36.6 ± 17.5	Refugees voluntarily screened at Dzaleka camp	Absent, < 10 yrs
[10]	Cross-sectional study	Kayseri City Hospital, Turkey	Syrian refugees	—	—	63	65.37 ± 10.63	≥ 18 yrs, scheduled for cataract surgery, no ocular/systemic inflammation	< 18 yrs, pseudophakia, keratoconus, unreadable keratometry
[16]	Retrospective consecutive case series	Hatay University Hospital, Turkey	Syrian war-affected civilians	194	18	212	29.5 ± 10.76	Syrian patients with ocular trauma referred between 2011–2018	Missing/unreadable data
[23]	Retrospective comparative study	American University Hospital, Beirut, Lebanon	War-affected civilians from Lebanese Civil War	461	83	544	22.98 ± 12.0
[31]	Pilot observational study	Refugee camps in Kavala (RACK) and Kos island (PROKEKA), Greece	Resettled refugees in Greece			58	NA
[28]	Retrospective audit (service‐based cross-sectional review)	Refugee Health Service (state-funded multidisciplinary new-arrival clinic), Adelaide, South Australia	Newly arrived refugees (forcibly displaced persons resettled in Australia)	56	68	124	NA

A total of eight studies were included in the meta-analysis assessing the prevalence of ophthalmic trauma, encompassing case series, cross-sectional studies, mixed-method studies, and retrospective cohort studies [9, 16, 22]. The overall pooled analysis demonstrated a prevalence of 22.7% (95% CI: 19.2%–26.7%), indicating a relatively high pooled event rate across the included studies. Individual study estimates varied widely. The case series by reported an exceptionally high prevalence of 99.8% (95% CI: 96.4%–100.0%). Among cross-sectional studies, prevalence estimates ranged from 0.4% to 23.6%. The mixed-method study reported a prevalence of 13.8% (95% CI: 7.8%–23.1%). Among retrospective cohort studies, prevalence estimates ranged from 3.2% (95% CI: 1.6%–6.2%) to 47.3% (95% CI: 4.6%–76.4%). Overall, the meta-analysis demonstrated considerable heterogeneity, with an I² statistic of 97.36%, reflecting substantial variability in prevalence estimates across study designs, populations, and methodological approaches (Fig. 2).

Fig. 2.

Forest plot of the pooled prevalence of ophthalmic injuries stratified by study design (random-effects model)

Phthisis bulbi (i.e. shrunken eye, with no functional vision), a severe and often irreversible consequence of ocular trauma, was analyzed in three studies [21, 23]. The pooled prevalence was 3.6% (95% CI: 1.0%–12.1%). Substantial heterogeneity was observed among the included studies (I² = 79.2%), indicating considerable variability in prevalence estimates across studies (Fig. 3).

Fig. 3.

Forest plot of the pooled prevalence of phthisis bulbi

A total of fourteen studies encompassing cohort, cross-sectional, mixed-method, retrospective cohort, and retrospective comparative designs were included in the meta-analysis assessing the prevalence of cataract [3, 9, 11, 18, 28]. The pooled prevalence estimates varied substantially across individual studies and study designs. In cohort studies, the pooled prevalence was 4.8% (95% CI: 4.6%–6.0%). Cross-sectional studies demonstrated a pooled prevalence of 8.4% (95% CI: 7.8%–9.1%), with individual estimates ranging widely across populations and settings. The mixed-method study reported a pooled prevalence of 12.5% (95% CI: 6.9%–21.7%). Retrospective cohort studies showed a higher pooled prevalence of 21.5% (95% CI: 17.6%–26.0%), while the retrospective comparative study reported a prevalence of 38.6% (95% CI: 34.6%–42.8%). Overall, there was substantial heterogeneity across studies, with an I² statistic exceeding 96% (Fig. 4).

Fig. 4.

Forest plot of the pooled prevalence of cataract stratified by study design

Nine studies were included in the meta-analysis to assess glaucoma prevalence, comprising cross-sectional, mixed-method, retrospective cohort, and retrospective comparative designs. Individual study prevalence estimates varied considerably, ranging from 0.1% to 6.8% across different populations and study designs [9, 11, 18–23, 26]. The pooled prevalence across all studies was 2.0% (95% CI: 0.6%–2.7%, Z = –27.551, p < 0.001). Cross-sectional studies reported generally lower prevalence estimates, mostly below 3%, whereas higher estimates were observed in mixed-method and retrospective cohort studies. The retrospective comparative study demonstrated a prevalence of 1.3% (95% CI: 0.6%–2.7%). Substantial heterogeneity was observed among the included studies (I² = 77.4%), indicating considerable between-study variability (Fig. 5).

Fig. 5.

Forest plot of the pooled prevalence of glaucoma stratified by study design

Endophthalmitis, a serious infection often secondary to penetrating trauma or surgery, was analyzed across three studies and yielded a pooled prevalence of 1.7% (95% CI: 1.0%–2.8%) [16, 22, 23]. Notably, no significant heterogeneity was observed for endophthalmitis (I² = 0%), suggesting more consistency across these studies (Fig. 6).

Fig. 6.

Forest plot of the pooled prevalence of endophthalmitis

A total of eight studies reported on the prevalence of lid and adnexal diseases [9, 11, 16, 18, 19, 22, 28, 31]. Using a random-effects model, subgroup analyses demonstrated variability in prevalence estimates across study designs. Cross-sectional studies reported a pooled prevalence of 28.0% (95% CI: 26.3%–29.8%), representing the highest contribution to the overall estimate. The mixed-method study yielded a pooled prevalence of 21.3% (95% CI: 13.6%–31.6%). In contrast, pilot and retrospective studies showed substantially lower prevalence, with a pooled estimate of 2.8% (95% CI: 1.8%–4.1%). Overall, the pooled estimates indicated considerable variability between study designs. Moderate-to-high heterogeneity was observed across studies (I² = 68.6%) (Fig. 7).

Fig. 7.

Forest plot of the pooled prevalence of disorders of the lid and adnexa

A total of eleven studies were included in the meta-analysis to measure the prevalence of refractive errors [3, 9–11, 18, 19, 21, 24, 25, 28, 31]. The pooled prevalence for cross-sectional studies was 26.0% (95% CI: 13.2%–44.6%), indicating a substantial burden within this study design. Marked heterogeneity was observed among cross-sectional studies (I² = 99.25%). The mixed-method study reported a prevalence of 37.5% (95% CI: 27.6%–48.5%), while the pilot observational study showed a prevalence of 16.4% (95% CI: 12.8%–20.8%). Among retrospective cohort studies the pooled prevalence was 46.1% (95% CI: 14.1%–81.6%) (Fig. 8).

Fig. 8.

Forest plot of the pooled prevalence of refractory eye diseases stratified by study design

Amblyopia, strabismus and binocular vision anomalies were also evaluated. Five studies were included in the meta-analysis assessing the prevalence of the outcome, with subgroup analysis performed according to study design [9, 11, 18, 20, 31]. Overall, the pooled event rate was 0.9% (95% CI: 0.3%–2.8%), indicating a low pooled prevalence across the included studies. The pooled event rate for cross-sectional studies was 0.8% (95% CI: 0.6%–1.0%), with substantial heterogeneity observed (I² = 90.7%). The mixed-method study reported a higher prevalence of 3.8% (95% CI: 1.2%–17.2%), while the pilot observational study reported a prevalence of 0.9% (95% CI: 0.3%–2.8%) (Fig. 9).

Fig. 9.

Forest plot of the pooled prevalence of amblyopia, strabismus, and binocular vision anomalies

A total of fourteen studies were included in the meta-analysis assessing the prevalence of blindness, with subgroup analysis performed according to study design [3, 5, 9, 11, 18, 22, 24–28]. The overall pooled event rate was 5.5% (95% CI: 0.7%–31.1%), indicating a low pooled prevalence with substantial variability across studies. The pooled event rate for cross-sectional studies was 3.4% (95% CI: 1.2%–9.7%), with considerable heterogeneity observed (I² = 98.9%). The clinic-based cohort study with structured outreach demonstrated a pooled event rate of 2.5% (95% CI: 2.0%–3.1%, Z = –9.622, p < 0.001). The mixed-method study reported a higher prevalence of 12.5% (95% CI: 6.9%–21.7%). The pooled event rate for retrospective studies was 5.5% (95% CI: 0.7%–31.1%), with considerable heterogeneity also observed (I² = 97.3%) (Fig. 10).

Fig. 10.

Forest plot of the pooled prevalence of blindness stratified by study design

Three studies reported on the prevalence of mild visual impairment, with a pooled event rate of 19.4% (95% CI: 10.7%–32.7%, Z = –3.983, p < 0.001) [3, 19, 28]. The mixed-method study showed the highest prevalence at 42.5%, though this was not statistically significant (p = 0.181), possibly due to sample size or methodological factors. In contrast, the cross-sectional study reported 13.6% with narrow confidence intervals and strong significance (p < 0.001). The retrospective audit-based review found a similar prevalence of 11.7% (p < 0.001). Despite the small number of studies, heterogeneity was high (I² = 95.7%), indicating notable variability in populations or study design (Fig. 11).

Fig. 11.

Forest plot of the pooled prevalence of mild visual impairment stratified by study design

The meta-analysis of moderate visual impairment included seven studies, showing an overall pooled event rate was 21.2% (95% CI: 8.1%–45.2%, Z = –2.298, p = 0.022), indicating a statistically significant pooled prevalence with substantial variability across studies [3, 11, 21, 22, 25, 26, 28]. Among cross-sectional studies, prevalence estimates ranged from 3.5% to 16.0%. The pooled prevalence for cross-sectional studies was 7.1% (95% CI: 4.2%–11.8%), with considerable heterogeneity observed (I² = 96.8%). The retrospective audit study by Murton (2024) reported a prevalence of 11.9% (95% CI: 9.4%–15.1%), consistent with the upper range of estimates observed in cross-sectional studies. Retrospective cohort studies demonstrated substantially higher prevalence estimates, ranging from 13.0% to 32.0%. The pooled prevalence for retrospective cohort studies was 21.2% (95% CI: 8.1%–45.2%), also showing considerable heterogeneity (I² = 95.3%) and reaching statistical significance (p = 0.022) (Fig. 12).

Fig. 12.

Forest plot of the pooled prevalence of moderate visual impairment stratified by study design

Seven studies assessed the event rate outcome, with a pooled overall event rate of 1.5% (95% CI: 1.3%–1.8%, Z = –43.032, p < 0.001) [3, 11, 20–22, 25, 28]. Subgroup analysis was performed based on study design. Cross-sectional studies reported consistently low event rates ranging from 0.5% to 1.7%, with all estimates reaching statistical significance (p < 0.001) and demonstrating moderate heterogeneity (I² = 50.1%). Retrospective audit data showed similarly low event rates, with Murton (2024) reporting an event rate of 0.6% (95% CI: 0.2–1.9). Retrospective cohort studies demonstrated higher and more variable event rates, ranging from 2.4% to 5.9%. All retrospective cohort study estimates were statistically significant (p < 0.001) and showed moderate heterogeneity (I² = 68.4%) (Fig. 13).

Fig. 13.

Forest plot of the pooled prevalence of severe visual impairment stratified by study design

Discussion

This systematic review demonstrates a disproportionately high burden of visual impairment and blindness among conflict-affected and forcibly displaced populations, positioning these outcomes as central indicators of compromised eye health in humanitarian settings. In our meta-analysis, the pooled prevalence of blindness was 2.5%, while moderate and severe visual impairment affected a substantial proportion of the population (pooled prevalence of severe visual impairment: 7.3%), alongside high levels of mild visual impairment. However, these pooled estimates were derived from a limited number of heterogeneous studies, and subgroup analyses showed substantial variability by study design, which may influence the stability of these summary estimates.

These estimates contrast sharply with global patterns reported in 2020, where blindness affected approximately 43.3 million people worldwide and represented a relatively small fraction of overall visual impairment, while the majority of the global burden was attributed to mild (258 million) and moderate-to-severe visual impairment (295 million), largely in non-conflict settings. Importantly, global trends over the past three decades show declining age-standardised prevalence of blindness and stable or only modest increases in moderate and severe visual impairment, whereas displaced populations in this review exhibit persistently elevated prevalence estimates, particularly for severe visual impairment and blindness. This comparison should be interpreted cautiously, as global estimates are age-standardised population-based figures, whereas several included studies in this review were facility-based or camp-based and may overestimate prevalence. Nevertheless, this divergence underscores the profound impact of conflict, displacement, delayed care, and health system disruption on ocular health outcomes [30].

Our study highlights the substantial burden of ocular trauma in conflict-affected areas and among displaced populations. The pooled prevalence of ophthalmic trauma was 22.7%, reflecting the profound direct and indirect impacts of armed conflict on eye health. This is mainly due to challenges faced in conflict settings including explosive injuries, delayed access to eye care and health systems collapse [29]. The predominance of trauma-related conditions ranging from to penetrating trauma in active conflict zones demonstrates how conflict-specific mechanisms influence ocular morbidity patterns. For example, both Syria and Lebanon saw disproportionately high rates of blast-related ocular injuries, while overcrowded and poorly maintained refugee camps, such as those housing the Rohingya, were associated with non-combat-related trauma [3, 13, 20, 21].

The prevalence of phthisis bulbi (3.6%) further emphasizes the severity of ocular trauma in conflict-affected settings and suggests substantial delays or limitations in access to definitive ophthalmic care. Phthisis bulbi represents an end-stage sequela of severe ocular injury, reflecting irreversible damage due to delayed or absent intervention, a situation more frequently encountered in war zones. However, this pooled estimate was derived from a small number of studies, and its generalisability across all humanitarian settings may be limited. In contrast, in settings with timely ophthalmic care, phthisis remains a rare consequence of ocular trauma or infection [31].

Furthermore, cataract was one of the most frequently reported non-traumatic conditions, with an overall pooled prevalence of 5.5%. These results are below the reported prevalence of cataract in some countries including Iran, as the prevalence of cataract was reported to be 17.2% in the population over 20 years old and 16.97% in the population 40–59 years old [32]. Our findings may underestimate the actual burden due to possible less geographic coverage in some conflict settings, and exclusion of undiagnosed cases who could not access healthcare services. Notably, methodological rigor and comprehensive screening strategies significantly influence detection rates. Moreover, different challenges in cataract surgical coverage in displaced settings were discussed including limited coverage, cost, surgical infrastructure, and safety issues [33].

Moreover, the reported glaucoma prevalence was 1.7%, which is lower than the prevalence rate reported by Tham et al. among population aged 40—80 years (3.54%) [34]. Our reported prevalence likely underrepresents due to inaccessibility to health services, and lack of humanitarian aids. To demonstrate, the asymptomatic nature of early glaucoma and the lack of advanced diagnostic tools such as perimetry or optical coherence tomography (OCT) in humanitarian settings impede early detection [35, 36].

Although endophthalmitis was relatively rare (1.7%), its prevalence was consistent with previous reports among patients with penetrating ocular trauma, where rates ranged from 0.9% to 18% [37]. This variability is primarily driven by wound-related factors, including delayed primary repair, wound contamination, and large or complex injuries [38]. Given the trauma-heavy case mix in conflict settings, even a relatively low pooled prevalence represents a clinically significant burden.

Furthermore, refractive errors demonstrated a high pooled prevalence of 26%. Globally, refractive disorders account for a substantial proportion of visual impairment, with Hashemi et al. estimating that approximately 42% of visual impairment worldwide is attributable to refractive errors [39]. In the present review, the reported prevalence reflects diagnosed refractive conditions and includes both uncorrected cases and cases corrected with eyeglasses following assessment, as this distinction was not consistently reported across included studies. These findings highlight a substantial unmet need for basic optometric services and access to corrective lenses in conflict-affected and displaced populations. Given that uncorrected refractive error is a leading and highly preventable cause of visual impairment worldwide, its high occurrence in these settings represents a major yet addressable public health gap [40].

Although our study had important findings, some limitations need to be addressed. For instance, the heterogeneity across studies was consistently high, driven by different methodologies, and population characteristics. Moreover, the reported cross-sectional designs frequently reported lower prevalence rates, while mixed-method and retrospective studies reported more cases due to enhanced data capture and clinical documentation. Variations in inclusion criteria, age groups, and diagnostic tools further led to between-study variability.

In summary, this systematic review demonstrates that visual impairment and blindness, particularly moderate-to-severe forms are markedly elevated among conflict-affected and displaced populations, with ocular trauma, uncorrected refractive error, and delayed treatment of chronic eye diseases acting as key drivers. Visual disorders and ocular pathologies are amplified by structural deficiencies in humanitarian healthcare systems. We call on humanitarian agencies to establish eye care framework that prioritize early detection and timely management of ocular conditions. Interventions targeting preventable causes of visual impairment including refractive error correction, cataract surgery, trauma management, and glaucoma screening should be central to humanitarian eye health strategies. In addition, more longitudinal studies must be prioritized with a focus on assessing visual rehabilitation, functional outcomes, and quality of life measures after treatment.

Conclusion

This systematic review reveals a high burden of ocular injuries and eye diseases among conflict-affected and displaced populations. Ophthalmic trauma was notably prevalent (22.7%), with serious complications like phthisis bulbi reflecting delayed care. Non-traumatic conditions such as cataract and glaucoma were also common but likely underestimated due to limited access to diagnostic services. Refractive errors showed the highest prevalence (26%), highlighting a major gap in basic eye care.

The wide variation among studies underscores challenges in data collection and healthcare accessibility. Overall, conflict and displacement amplify ocular morbidity, compounded by fragile health systems and inadequate eye care infrastructure.

These findings call for urgent integration of eye care services within humanitarian responses, emphasizing early detection, treatment, and rehabilitation. Further research focusing on long-term outcomes and quality of life is essential to inform effective interventions and reduce preventable vision loss in these vulnerable populations.

Author contributions

F.E.A.M: conceptualization, project leadership, writing of original draft, screening, data extraction, revision and editing of the final draft.—A.A: protocol preparations, manuscript writing, screening.—J.M.A: screening, data extraction.—R.M.A.J: data extraction, manuscript writing.—A.G.A: screening, risk of bias assessment, manuscript writing.—A.O.A.K: screening, manuscript writing.—S.M.A: data extraction, manuscript writing.—K.T.H: data extraction, manuscript writing.—A.H: data extraction and manuscript writing.—A.A: data extraction and manuscript writing.—B.MA: manuscript writing.—A.S.A.A: manuscript writing.—S.A: screening, manuscript writing.—S.SK.A: manuscript writing.—T.A.A.E: manuscript revision and writing.—All the authors approved the final version of the manuscript.

Funding

The authors declare that no financial support was received.

Data availability

Data is available and could be provided by the corresponding author upon a reasonable request.

Declarations

Ethics and consent to participate

Not applicable.

Consent for publication

Not applicable.

Competing of interests

The authors declare no competing interests.