Prevalence and associated factors of pseudoexfoliation syndrome among cataract patients attending comprehensive specialized hospitals in Northwest Ethiopia

Abstract

Pseudoexfoliation syndrome is a common age-related disorder characterized by the accumulation of extracellular fibrillar material in various systemic and ocular tissues, particularly on the lens capsule, iris, and trabecular meshwork. The prevalence of pseudoexfoliation syndrome varies worldwide due to differences in geographic location, ethnic background, and environmental factors. This condition has a significant impact on ocular health, particularly among older adults, as it can complicate cataract surgery and is associated with severe forms of glaucoma that are often difficult to manage. A hospital-based retrospective cross-sectional study was conducted at Debre Markos and Felege Hiwot comprehensive specialized hospitals. The study reviewed medical records of cataract patients aged 40 years and above who attended the hospitals from January to July 2023. All consecutive eligible records were included. Data were extracted using a structured data extraction tool from June 12 to July 12, 2023. A total of 880 medical records of cataract patients were analyzed. The median age of the participants was 68 years, with an interquartile range of 18. The overall proportion of pseudoexfoliation syndrome was 38%. Factors independently associated with pseudoexfoliation syndrome included outdoor activity (AOR = 6.75, 95% CI 1.99, 8.35), older age (AOR = 5.50, 95% CI 3.75, 8.95), hypertension (AOR = 4.00, 95% CI 2.56, 5.98), glaucoma (AOR = 4.00, 95% CI 2.33, 7.39), nuclear cataract (AOR = 3.98, 95% CI 2.01, 8.94), rural residence (AOR = 3.80, 95% CI 1.99, 6.44), male patients (AOR = 2.01, 95% CI 1.44, 6.43) and high intraocular pressure (AOR = 1.5, 95% CI 1.25, 8.00). The prevalence of pseudoexfoliation syndrome among cataract patients in this study was relatively high. The condition was more frequently observed among participants aged 40 years and above. The findings may contribute to the understanding of pseudoexfoliation syndrome in cataract patients.

Introduction

Pseudoexfoliation syndrome (PXF) was initially described by Lindberg in 1917 in Finnish patients, and the syndrome has since been recognized all over the world^1,2. PXF syndrome is a common age-related disorder characterized by the accumulation of extracellular fibrillar material in many systemic and ocular tissues, particularly on the lens capsule, iris, and trabecular meshwork³. Globally, the prevalence of PXF differs across regions, depending on geographic location, ethnic background, and environmental conditions^4–6. The reasons for the differences in prevalence are not well understood. These variations might be from actual biological or ecological factors, or they might be due to discrepancies in examination methods and diagnostic capabilities⁷.

Numerous studies have suggested that factors such as age, sex, intraocular pressure (IOP), ultraviolet exposure, type of cataract, glaucoma, and systemic conditions like hypertension have been associated with the development of PXF^2,8,9. PXF significantly affects eye health, especially in older adults, by complicating cataract surgery and causing severe, hard-to-control glaucoma^10,11. These challenges worsen visual outcomes, reduce quality of life, and increase healthcare burdens^10,11.

The prevalence of PXF has been examined across different countries, showing a global range of 1.5% to 40.9%^12,13. Research shows that the prevalence in European countries ranges from 3.6 to 34.2%^14,15. In Asian countries, rates vary between 1.5% and 22.1%^12,16. while in Africa, the reported prevalence ranges from 1.5% to 40.9%^13,17. In Ethiopia, the reported prevalence falls between 12 and 39.3%^2,18. However, most existing studies on PXF in Ethiopia are limited to a single institution, which is limited by localized population characteristics, referral patterns, and healthcare practices. Determining the prevalence and associated factors across multiple institutions can enhance clinical management and prevention efforts by offering a more comprehensive and representative view of the condition. Therefore, the aim of this study was to assess the prevalence of PXF and its associated factors among cataract patients at Debre Markos and Felege Hiwot Comprehensive Specialized Hospitals in Northwest Ethiopia, 2023.

Methods and materials

Study design, setting, and period

A hospital-based retrospective cross-sectional study was conducted at Debre Markos and Felege Hiwot Comprehensive Specialized Hospitals. The study reviewed medical records of cataract patients aged 40 years and above who attended the hospitals from January to July 2023. Data were extracted using a structured data extraction tool from June 12 to July 12, 2023. Debre Markos Hospital is located in the East Gojjam Zone of Amhara Regional State; it is 299 km away from the capital city, Addis Ababa. Felege Hiwot Hospital is located in the West Gojjam Zone of Amhara Regional State, about 567 km away from Addis Ababa. According to the hospital’s health information system, both hospitals are major referral centers and each hospital offers a wide range of specialized medical services to a population of over five million people.

Study population and eligibility criteria

All consecutive medical records of cataract patients aged 40 years and above with sufficiently complete information were included in the study. However, medical records of adult ophthalmic cataract patients’ charts over 40 years with corneal opacity or angle-closure glaucoma were excluded, as these conditions interfere with anterior segment examination.

Operational definitions

Participants were classified as having PXF if any pseudoexfoliation material was observed.

on the iris or lens capsule on dilated slit-lamp examination in either eye¹⁹.

Sampling technique

A consecutive sampling method was employed to select patient charts for this retrospective study. A total of 880 medical records of cataract patients aged ≥ 40 years who attended Debre Markos and Felege Hiwot Comprehensive Specialized Hospitals from January to July 2023 during the specified study period from June 12 to July 12, 2023, were reviewed. Charts were included consecutively based on their order of presentation until the desired sample size was reached.

Data collection tools and procedures

Medical records of cataract patients who attended Debre Markos and Felege Hiwot Comprehensive Specialized Hospitals from January to July 2023 during the study period were reviewed. Data for this retrospective chart review study were collected by trained graduate and experienced optometry students using a structured data extraction checklist developed based on relevant literature and clinical guidelines related to PXF syndrome and cataract patients. The checklist included patient demographic data, clinical findings, and diagnosis of pseudoexfoliation syndrome, cataract characteristics, and associated risk factors such as age, sex, systemic diseases, and ocular history.

Data quality assurance

To ensure data quality, a pre-test was conducted on 5% of the total sample at the University of Gondar tertiary eye care and training center prior to the main data collection. Data collectors received training from the principal investigator on standardized data extraction procedures. The overall data collection process was supervised by a senior optometrist to ensure data completeness and consistency. Since medical records with complete data for main and independent study variables were included, imputation methods and other management of missing data were not applied.

Data processing and analysis

The data were coded, verified, cleaned, and entered using Epi Info version 7 software. After cleaning, the data were exported to the Statistical Package for Social Sciences (SPSS) version 25 for further analysis. Both descriptive and analytical statistical methods were applied. Descriptive statistics such as mean, median, frequency, and cross-tabulations were used to summarize the data. To identify significant factors associated with PXF, binary logistic regression was applied. Variables that had a P-value of less than 0.2 in the variable analysis were included in the multivariable binary logistic regression. A significance level of P < 0.05 was used to determine statistical significance. Finally the findings were presented in narrative form and organized in tables.

Results

Socio-demographic characteristics

The study sample comprised a total of 880 medical records of participants, aged 40 years and above. The median age of the participants was 68 years, with an interquartile range of 18. Among the study participants, males had a slightly higher proportion of 54.5% compared to females 45.5%. The majority of respondents lived in rural areas, accounting for 56.2%, whereas 43.8% resided in urban settings. Regarding occupational activity, 55.1% were engaged in outdoor activities, while 44.9% performed indoor activities (Table 1).

Table 1.

Sociodemographic characteristics of the study participants, among cataract patients, 2023 (n = 880).

Variables	Categorize	Frequency (n)	Percentage (%)
Sex	Male	480	54.5
	Female	400	45.5
Age (years)	40–58	290	33.0
	59–77	360	40.9
	78–80	230	26.1
Residency	Urban	334	38.0
	Rural	546	62.0
Marital status	Currently married	576	65.5
	currently single	304	34.5
Educational status	Formal education	280	31.8
	Non-formal education	600	68.2
Occupational status	Farmer	344	39.0
	Government employed	155	17.6
	House wife	180	20.5
	Merchant	102	11.6
	Unemployed	99	11.3
Health insurance	Yes	500	56.8
	No	380	43.2
Occupation	Indoor activity	350	39.8
	Outdoor activity	530	60.2

Clinical characteristics of the study participants

In this study, hypertension was present in 5.0% of the respondents. Glaucoma was diagnosed in 6.3% of the participants. 31% had elevated IOP values greater than 21 mmHg. The distribution of cataract types was varied, with nuclear cataracts being the most common, 32.7%, followed by mixed cataracts, 27.3% (Table 2).

Table 2.

Clinical characteristics of the study participants, among cataract patients, 2023 (n = 880).

Variables	Categories	Frequency (n)	Percent (%)
Diabetes mellitus	Yes	50	5.7
	No	830	94.3
Diabetic retinopathy	Yes	16	1.8
	No	864	98.2
Hypertension	Yes	44	5.0
	No	836	95.0
Glaucoma	Yes	55	6.3
	No	825	93.7
IOP	≤ 21	607	69.0
	> 21	273	31.0
Type of cataract	Capsular cataract	150	17.0
	Nuclear cataract	288	32.7
	Cortical cataract	202	23.0
	mixed cataract	240	27.3

IOP: intraocular pressure.

Proportion of pseudoexfoliation syndrome

The presence of PXF was observed in 334 participants, representing 38% of the study group (95% CI, 33.7–44.6). Of those with PXF, 134(40.2%) had PXF at the pupillary border, 107(32%) had PXF at the lens capsule, and 93 (27.8%) had PXF at both the pupillary border and the lens capsule.

Factors associated with PXF

By using a bivariable binary logistic regression analysis, male sex, older age, outdoor activity, rural residence, glaucoma, high IOP, diabetes mellitus, hypertension, and nuclear cataract were independently associated with PXF. However, in multivariable binary logistic regression analysis, male sex, older age, outdoor activity, rural residence, glaucoma, high IOP, hypertension, and nuclear cataract remained significantly associated with PXF.

The odds of developing PXF among male participants were 2.01 times (AOR = 2.01, 95% CI: 1.44, 6.43) higher than females participates. Participants aged above 78 years were 5.50 times (AOR = 5.50, 95% CI: 3.75, 8.95) more likely to develop PXF than participants aged 40–58 years. The odds of developing PXF in rural residences were 3.80 times (AOR = 3.80, 95% CI: 1.99, 6.44), more likely to have than those in urban residences.

Participants who engage in outdoor activities are 6.75 times (AOR = 6.75, 95% CI: 1.99, 8.35) more likely to develop PXF compared to those who engage in indoor activities. Additionally, the odds of developing PXF among hypertensive participants were 4.00 times (AOR = 4.00, 95% CI: 2.56, 598) higher than non-hypertensive participants. Participants with high IOP were 1.5 times (AOR = 1.5, 95% CI: 1.25, 8.00) more likely to develop PXF than participants with normal IOP.

Participants who had glaucoma were 4.00 times (AOR = 4.00, 95% CI: 2.33, 7.39) more likely to develop PXF compared to those participants who did not glaucoma. The odds of developing PXF for those participants with nuclear cataract were 3.98 times (AOR = 3.98, 95% CI: 2.01, 8.94) higher than those of participants without nuclear cataract (Table 3).

Table 3.

Factors associated with the proportion of pseudoexfoliation syndrome, 2023 (n = 880).

Variables	Pseudoexfoliation syndrome
	Yes	No	COR (95% CI)	AOR (95% CI)	P- value
Sex
Male	255	225	4.61(1.95–8.88)	2.01(1.44–6.43)	0.03
Female	79	321	1.00	1.00
Age ( years)
40–58	54	236	1.00	1.00
59–77	112	248	1.97(1.30–2.76)	2.50(1.57–5.43)	0.67
78–80	168	62	10.84(4.55–12.63)	5.50(3.75–8.95)	0.007
Residency
Urban	84	250	1.00	1.00
Rural	250	296	2.51(2.01–7.86)	3.80(1.99–6.44)	0.01
Occupation
Indoor activity	50	300	1.00	1.00
Outdoor activity	284	296	5.76(1.69-11.00)	6.75(1.99–8.35)	0.005
Diabetes mellitus
Yes	22	28	1.30(0.75–9.76)	2.87(0.42–5.99)	0.78
No	312	518	1.00	1.00
Hypertension
Yes	25	19	2.24(1.67–5.98)	4(2.56–5.98)	0.04
No	309	527	1.00	1.00
Glaucoma
Yes	39	16	4.38(2.93–9.92)	4.00(2.33–7.39)	0.009
No	295	530	1.00	1.00
IOP
≤ 21	203	404	1.00	1.00
> 21	131	142	1,84(1.33–8.71)	1.5(1.25-8.00)	0.043
Type of cataract
Capsular cataract	43	107	1.00	1.00
Nuclear cataract	179	109	4.09(2.49–11.770)	3.98(2.01–8.94)	0.008
Cortical cataract	67	135	1.23(0.78–12.66)	0.75(0.55–9.36)	0.79
Mixed cataract	45	195	0.57(0.89–7.94)	0.33(0.27–6.88)	0.54

COR: Crude Odds Ratio, AOR: Adjusted Odds Ratio, IOP: Intraocular Pressure, CI: Confidence Interval.

Discussion

In this study, we found that the presence of PXF among cataract patients attending Debre Markos and Felege Hiwot Comprehensive Specialized Hospitals was 38% (95% CI, 33.7–44.6), which is higher than many regional and international reports, indicating a substantial burden of the condition in this population, and suggests the importance of careful screening and clinical attention among cataract patients. The prevalence of PXF observed in our study is in line with previous findings from Gondar, Ethiopia⁸, Addis Ababa, Ethiopia² and Somali¹³. This similarity could be due to the fact that all the studies were conducted in a hospital setting. However, our prevalence is markedly higher than figures reported in many other studies conducted in central Ethiopia (13.5%)²⁰, Nigeria (1.5%)¹⁷, Japan (1.5%)¹², India (22.1%)¹⁶, Latvia (21.6%)²¹, Turkey (11%)²² and Russia (3.6%)¹⁴. The reason for this discrepancy may be attributed to the different study settings, as this research was conducted in hospital-setting, whereas others were conducted in community settings. Additionally, differences in geographic location, ethnic background, and environmental conditions might also contribute to this variation.

In this study, male participants were 2.01 times more likely to have PXF than females. This result agrees with previous studies in Jordan²³. The potential association might be due to a complex interplay of biological vulnerability and environmental factors²⁴. The current study found that older participants was 5.50 times more likely to develop PXF compared with younger participants, which is in line with studies in Gondar, Ethiopia⁸, Gurage, Ethiopia²⁵, Somali¹³, Korea²⁶, and Spain²⁷. The association between advancing age and increased prevalence of pseudoexfoliation syndrome is strongly and significantly associated, likely due to age-related changes in gene expression and environmental interactions^7,8. Rural residences were 3.80 times more likely to have PXF compared to urban residences. This study was similar to studies done in Gondar, Ethiopia⁸ and India¹⁶. The significance of this correlation may arise from the higher cumulative exposure of rural populations to outdoor sunlight and other environmental factors that increase the risk of PXF.

In the current study, participants with outdoor activity had a 6.75 more likely to have PXF than those with indoor activity. This study result was consistent with studies done in Gondar, Ethiopia⁸. This association is primarily due to outdoor activities’ impact on PXF risk by increasing eye exposure to ultraviolet radiation and environmental factors that contribute to the syndrome, while indoor activities pose a lower risk due to limited exposure to those factors²⁸. Moreover, hypertension was significantly associated with the presence of PXF than those without hypertension. This finding was consistent with the studies done in Australia²⁹. Although the reason for this association cannot be inferred in this cross-sectional study, the association may reflect shared systemic vascular changes, such as increased vascular resistance, decreased blood flow, vascular dysregulation, and altered autonomic control, which have been observed in individuals with both hypertension and PXF³⁰.

Our study also reported that participants with glaucoma were 4.00 times more likely to develop PXF than participants without glaucoma. The study is similar to studies carried out in Gondar, Ethiopia⁸, Somali¹³, and Spain²⁷. This increased likelihood might be due to shared ocular changes, such as deposits of extracellular fibrillar material in the trabecular meshwork, which are commonly observed in both conditions, highlighting the importance of careful ocular examination in glaucoma patients to detect early. Study participants with high IOP were 1.5 times more likely to experience in PXF compared to those with normal IOP, which is comparable with studies conducted in Gondar, Ethiopia⁸, Gurage, Ethiopia²⁵,Somali¹³, and Spain²⁷. This association may reflect previously reported mechanisms where PXF material accumulation can affect aqueous humor outflow, resulting in an increase in IOP, and this observed relationship likely reflects elevated IOP as a consequence of PXF related to obstruct normal drainage of aqueous humor rather than a causative factor in the development of PXF⁸. In addition, the study reported that participants who had nuclear cataract were 3.98 times higher risk of developing PXF than participants without nuclear cataract. This finding is supported by research conducted in Spain²⁷. This association might be due to several mechanisms. Nuclear cataract reflects long-standing oxidative stress and metabolic dysfunction within the anterior segment of the eye. This chronic oxidative damage, which plays a central role in nuclear sclerosis, might also stimulate abnormal extracellular matrix metabolism and fibrillar material production, contributing to the development of PXF. In addition, both nuclear cataract, and PXF are strongly age dependent condition and their co-existence might also reflect shared pathological pathway for the association, this highlighting a potential link between these conditions without implying direct causation²⁷.

Strengths and limitations of the study

The major strength of this study is the inclusion of patients primarily diagnosed with cataract. This allowed the evaluation of a clinically relevant population that includes individuals at risk for PXF. However, certain limitations should be acknowledged. First, although only medical records with complete data on the main study variables and independent variables were included, the study relied on secondary data, which may still be subject to documentation errors or inconsistencies. Second, the study was conducted at two hospital settings, which may limit generalizability of the finding to the wider population. Third, because of the cross-sectional retrospective design, causal relationship between PXF syndrome and the associated factors cannot be established. Finally, the study includes only cataract patients attending hospitals, which may be affected by selection bias.

Conclusion

The prevalence of PXF is high among cataract patients at Debre Markos and Felege Hiwot Comprehensive Specialized Hospitals. It is independently associated with factors such as older age, male sex, outdoor activity, rural residence, glaucoma, high IOP, hypertension, and nuclear cataract. These finding suggests the importance careful ocular examination among cataract patients, particularly in high risk groups.

Author contributions

H. A .J has conceptualized the study and set the objectives, developed the proposal. M.A.T and A.Z.B have participated in data management, statistical analysis, and manuscript preparation. All authors approved the final manuscript.

Data availability

The corresponding author can provide the data and materials used in this study upon a reasonable request.

Declarations

Competing interests

The authors declare no competing interests.

Ethical approval and consent to participate

Ethical approval for this study was granted by the ethical review committee of the College of Medicine and Health Sciences at the University of Gondar. The research adhered to the principles set forth in the Declaration of Helsinki. After the purpose of the study was described, written informed consent from each of the participant was not required by the ethical review committee of the University of Gondar. The participant’s consent was waived because this was a retrospective study through document review. Confidentiality was maintained by coding the files and removing patients’ names to protect their privacy.