Prevalence; Distribution and Determinants of Myopia in Owerri; Nigeria

Background: Uncorrected myopia is a significant cause of visual impairment and avoidable blindness. Incidence of open-angle glaucoma has been shown to occur more often in myopia. This cross-sectional analytical study determined the prevalence; distribution and determinants of myopia in the adult population of Imo State; Nigeria with a view to establish a reference data for research purposes and future intervention in this locality. Materials and Method: A total of 3451 adults living in Owerri consisting of 2606 persons as test group and 845 persons as controls were randomly selected using standard optometric methods including subjective refraction. Results: Refractive error (ametropia) was found in 79.5 study and 76.8 control. Myopia was found in 23.4 study and 19.6 control. Highest prevalence of myopia was observed in females aged 40-49 years. Fifty percent of study and 68.1 of control group had myopia of -0.50DS to -3.00DS while 4.0 and 2.4 of study and control group respectively had myopic astigmatism. In all; 27.7 study and 16.2 control had myopia 5.00DS. The highest degree of myopia found in this study was - 24.00DS. Conclusion: This study provided information on the prevalence; distribution and determinants of myopia in Owerri; Nigeria and the data could be a basis for improved visual health care in the south-eastern sub-region of Nigeria

Astigmatism: Prevalence; Distribution and Determinants in Owerri; Nigeria

Background: Astigmatism impairs focusing ability of the eyes at far and near distances. This causes distortion; blurred vision; eye strain; headache; makes difficult visual tasks such as reading; driving (especially at night); focusing on the classroom board and computer screen. This study determined the prevalence; distribution and determinants of astigmatism in Owerri; Imo State; Nigeria in order to establish a baseline data for the state. Materials and Methods: Three thousand; four hundred and fifty - one adults consisting of 2606 persons as test subjects and 845 persons as controls were randomly selected for the study. Structured - questionnaire was administered to the subjects and thereafter; the visual acuity at far and near including tonometry; ophthalmoscopy; perimetry; retinoscopy and subjective refraction were done. Astigmatic correction was prescribed in the minus cylinder format and astigmatism was defined as a cylindrical error less than -0.50 diopter cylinder in any axis. Astigmatism was classified by axis as with-the-rule (WTR); against-the-rule; and oblique astigmatism. Results: A prevalence of 20.9 and 22.5 of astigmatism was found in the study and control groups respectively. From the astigmatics; 59.4 and 61.1 of females in the study and control groups respectively (especially females aged 40-49) were mostly affected. WTR astigmatism of =1.00DC (P = 0.000) was statistically significant between study and control groups. A higher prevalence of astigmatism was found in subjects domiciled in the rural areas and caused by factors like environmental influences; poor nutrition and irrational first line drug use of chloroquine. Conclusion: To achieve the targets of vision 2020; we recommend periodic visual examination and health education on diet; drug use and safe environmental practises especially for people living in rural areas in low income economy like ours

Presbyopia: Prevalence; Distribution and Determinants in Owerri; Nigeria

Background: Presbyopia causes blurring and impairment of vision at near. It is the most common physiologic change in the adult eye with advancing age. Good near vision is a necessity for domestic activities; office work and near vision tasks other than reading and writing; especially among adults in a resource-limited economy. The study determined the prevalence; distribution and determinants of presbyopia; presbyopic spectacle coverage; and provided data for ready-made near vision spectacles in Imo State; Nigeria. Materials and Methods: A total of three thousand; four hundred and fifty-one adults consisting of 2606 persons as study group and 845 persons as controls were randomly selected for the study. Structured questionnaire was administered to the subjects. Their visual acuity at far and near including tonometry; ophthalmoscopy; perimetry; retinoscopy and subjective refraction were done. Subjects who could not read N6 and emmetropes; who are 40 years and above were considered as presbyopic. Results: The prevalence of presbyopia was 70.9 and 75.0 of study and control groups respectively. Females aged 40-49 were in the majority (57.1 and 51.9 of females in the study and control groups respectively). Subjects requiring additions at near of ?+1.50DS to 2.00DS were in the majority (39.0 and 46.4 of study and control groups respectively). Amongst the presbyopes 61.3 and 78.7 of study and control groups respectively did not have presbyopic correction. The subjects were also ignorant of corneal inlay technology in treatment of presbyopia. A higher prevalence exists among rural dwellers and the contributory factors were environmental influences; poor nutrition and irrational use of chloroquine for treatment of malaria. Conclusion: Over seventy-percent of presbyopia was found in this study. The determinants were age; gender; nutrition and drug use. Majority of the presbyopes were domicile in the rural area and did not have corrective spectacles. We recommend visual health education; regular vision screening and intervention to achieve the targets of vision 2020 in low-and-medium-income countries