**Background:** Glaucoma is a chronic blinding condition often treated with topical anti-glaucoma medications containing preservatives like benzalkonium chloride, which can cause ocular surface changes and dry eye syndrome (DES). DES negatively impacts quality of life (QOL), but limited research has compared different questionnaires and objective methods to assess DES in glaucoma patients, especially in African populations. This study aimed to ascertain the presence of DES in glaucoma patients using subjective and objective methods and examine its impact on QOL.
**Methods:** A hospital-based, descriptive cross-sectional study was conducted among 156 glaucoma patients (mean age 47.88 ± 16.0 years; 81 females, 75 males) from three referral facilities in Cape Coast Metropolis, Ghana, between February and May 2019. Inclusion criteria: confirmed glaucoma patients aged ≥18 years, on topical anti-glaucoma medication (with preservative) for ≥6 months, best-corrected visual acuity ≤0.7 logMAR in the worst eye. Exclusion criteria: systemic conditions affecting ocular surface (e.g., rheumatoid arthritis, Sjogren’s syndrome), ocular conditions (e.g., infectious diseases, corneal abrasion, pterygium), absolute central visual field defect, ocular surgery in preceding 6 months, allergy to medication, use of tear supplements, or prior DES diagnosis/treatment. Participants underwent external ocular examination, tear break-up time (TBUT; abnormal <10 seconds), corneal staining (graded 0–3 in 5 regions), Schirmer test I (ST; abnormal ≤10 mm/5min without anesthesia), and completed three questionnaires: 25-item National Eye Institute Visual Function Questionnaire (NEI-VFQ-25; scores 0–100, lower=worse), Ocular Surface Disease Index (OSDI; scores 0–100, normal 0–12, mild 13–22, moderate 23–32, severe 33–100), and Dry Eye-related Quality of Life Score (DEQS; scores 0–48, higher=worse impact). Definite dry eye was defined as simultaneous presence of symptoms (OSDI ≥13) and at least one sign (TBUT ≤10 sec or ST ≤10 mm/5min or positive staining). Patients were divided into four groups: Group A (no DES, n=10), Group B (definite DES, n=96), Group C (asymptomatic with sign, n=21), Group D (symptomatic with no sign, n=29). Statistical analysis included one-way ANOVA, multivariate logistic regression, and correlation analyses.
**Key Results:** The majority of participants (71.8%) had abnormal TBUT (<10 sec), and 58.3% had insufficient tear production (ST ≤10 mm). Among subgroups, TBUT values were significantly lower in Group B (definite DES) compared to Groups A and D in both eyes [right eye: F(3,151)=13.703, p<0.001; left eye: F(3,152)=18.992, p<0.001]. Similarly, ST values were significantly lower in Groups B and C compared to Groups A and D [right eye: F(3,151)=28.895, p<0.001; left eye: F(3,152)=17.410, p<0.001]. The mean NEI-VFQ-25 composite score was 64.93 ± 20.27. The ocular pain subscale score was significantly lower in Group B (56.64 ± 21.40) compared to Groups A (71.20 ± 20.92), C (69.71 ± 20.78), and D (69.66 ± 24.42) [F(3,152)=4.559, p=0.004]. OSDI scores were significantly higher in Groups B (47.69 ± 19.17) and D (38.90 ± 22.44) than in Groups A and C [F(3,152)=17.896, p<0.001]. DEQS scores showed a similar trend [F(3,152)=8.775, p<0.001]. There was a strong correlation between OSDI and DEQS (r=0.604, p<0.001), but weak correlations between NEI-VFQ-25 composite and OSDI (r=-0.234, p=0.003) and DEQS (r=-0.217, p=0.0071). Multivariate logistic regression revealed that patients using combination therapy (beta-blocker + alpha-2 agonist) had lower odds of DES compared to those using beta-blockers alone (AOR=0.159, 95% CI 0.038–0.662).
**Clinical Implications:** This study demonstrates a high prevalence of DES (61.5% definite) among glaucoma patients on topical therapy, significantly reducing vision-related QOL, particularly through ocular pain. Dry eye symptom questionnaires (OSDI, DEQS, NEI-VFQ-25) show adequate measurement precision and psychometric validity for clinical assessment in this population. The findings underscore the importance of routine ocular surface evaluation in glaucoma patients to detect and manage DES early, potentially improving treatment compliance and QOL. Clinicians should consider both subjective symptoms and objective signs when diagnosing DES, as some symptomatic patients may lack clinical signs. The study also highlights that beta-blocker use is associated with higher odds of DES, while combination therapy may reduce risk. Limitations include the lack of data on medication duration, dose frequency, compliance, and glaucoma severity, as well as the exclusion of patients with prior DES, which may underestimate prevalence. Future large-scale randomized controlled trials are needed to compare toxic effects of specific medications and their impact on QOL.