Visual impairment and blindness in a population-based study of Mashhad, Iran

Abstract

PurposeTo determine the prevalence of visual impairment and blindness and related factors in the 1- to 90-year-old urban population of Mashhad.MethodsIn this cross-sectional study of 1- to 90-year-old residents of Mashhad, in northeastern Iran, sampling was done through random stratified cluster sampling (120 clusters). After selecting the samples and their participation in the study, all subjects had vision testing including measurement of visual acuity and refraction, as well as examinations with the slit-lamp and ophthalmoscopy. Visual impairment (primary outcomes) was defined as a visual acuity worse than of 0.5 logMAR (20/60) in the better eye.ResultsOf the 4453 selected persons, 3132 (70.4%) participated in the study. The prevalence of visual impairment based on presenting vision and best-corrected vision was 3.95% (95% confidence interval [CI]: 3.13–4.77) and 2.23 (95% CI: 1.54–2.91), respectively. The prevalence of presenting visual impairment increased from 1.59% in children under 5 years of age to 43.59% in people older than 65 years of age; these figures were respectively 1.59% and 42.31% based on corrected visual acuity. In the logistic regression model, older age (OR = 1.06, 95% CI: 1.04–1.07, P < 0.001), higher education (OR = 0.16, 95% CI: 0.06–0.38, P < 0.001), and low income (OR = 1.36, 95% CI: 1.21–1.72, P < 0.001) correlated with impaired sight. Based on presenting vision and best-corrected vision, the prevalence of blindness was 0.86% (95% CI: 0.51–1.22) and 0.32% (95% CI: 0.1–0.55). The most common causes of visual impairment were uncorrected refractive error (41.8%) and cataract (20%).ConclusionsAccording to our findings, the prevalence of visual impairment was intermediate in comparison with other studies. The prevalence of visual impairment in our study was similar to the global average; however, it was markedly high at older ages. Nonetheless, refractive errors and cataracts remain as the main causes of impaired vision and blindness in this population, while these two conditions are easily treatable with correction or surgery.

Proportion and Associated Factors of Low Vision among Adult Patients Attending at University of Gondar Tertiary Eye Care and Training Center, Gondar Town, Ethiopia

“…Besides, the variation in a socioeconomic characteristic of the study population could also contribute to this difference. On the other hand, the result of this study is higher than studies done in the Gurage Zone of Ethiopia (12.1%) [15] and a national survey of Ethiopia (3.7%) [4], Afghanistan (13.9%) [9], Sri Lankan (19.6%) [10], Indian states (9.2-22.1%) [8,11,12], Malaysia (7%) [7], and Iran (3.09%) [6]. is difference might be due to the variation in sampling design and sample size in which those studies were done at the community level with a larger sample size.…”

“…e possible reasons for this variation could be that females have had longer life expectancy than males, which in turn leads to developing eye conditions that could be increasing low vision [23]. Also, this might be happening because females could have unequal access for eye care services in some rural areas and the social stigma of wearing spectacles [18], whereas studies were done in Afghanistan, Sri Lankan, North India, and Iran reported that gender was not associated with low vision [6,[9][10][11].…”

“…Population-based studies conducted in Asian countries reported that the prevalence of low vision ranges from 3.09% to 22.1% [6][7][8][9][10][11][12]. On the other hand, institution-based research studies done in Africa showed that the prevalence of low vision extends from 17.1% to 28.2% [13,14].…”

Visual impairment and some of ocular problem in nursing home residents

“…According to Table 4, which presents the prevalence of VI in similar studies, the prevalence of VI in our study was higher than some (de Winter et al, 2004; Friedman et al, 2004; Horowitz, 1994; Mitchell et al, 1997; Owsley et al, 2007a; Tielsch et al, 1995; West et al, 2003; Whitmore, 1989) and lower than some other studies (VanNewkirk et al, 2000; Waked, Saad, Mehanna, Sleilaty, & Kortbaoui, 2007), which could be due to differences in the definition or ethnicity and race of the participants. On the other hand, the prevalence of VI in our participants was 4–20 times higher when compared to its prevalence in similar age groups of community-dwelling people, as domestic studies have reported a prevalence of 2–11% (Hashemi, Khabazkhoob, Emamian et al, 2012; Hashemi, Khabazkhoob, Saatchi, Ostadimoghaddam, Yekta, 2017; Hashemi, Yekta, et al, 2017; Yekta et al, 2011; Yekta, Hashemi, Ostadimoghaddam, Shafaee, Norouzirad, Radaye-moghaddam, et al, 2013), which is far lower than our results. In line with our study, some other studies have also reported a higher prevalence of VI in NHRs as compared to community-dwelling older persons (de Winter et al, 2004; Horowitz, 1994; Klein et al, 1991; Mitchell et al, 1997; Owsley et al, 2007a; Taiel-Sartral et al, 1999; Tielsch et al, 1995; Van der Pols et al, 2000; VanNewkirk et al, 2000; West et al, 2003; Whitmore, 1989).…”

Development and evaluation of performance characteristics of timolol-loaded composite ocular films as potential delivery platforms for treatment of glaucoma

“…It has been reported that approximately 4% of the world's population are visually impaired (Hashemi et al, 2017). This figure could significantly reduce if more efficient ocular dosage forms existed.…”