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 Table of Contents  
ORIGINAL ARTICLE
Year : 2016  |  Volume : 23  |  Issue : 3  |  Page : 132-136

Presbyopia and near spectacle correction coverage among public school teachers in Ifo Township, South-West Nigeria


1 Department of Ophthalmology, University of California, San Francisco, USA
2 Department of Ophthalmology, Guinness Eye Centre, Lagos University Teaching Hospital, College of Medicine, University of Lagos, Nigeria

Date of Web Publication12-Sep-2016

Correspondence Address:
Oluwatobi Olalekan Idowu
Department of Ophthalmology, University of California, San Francisco
USA
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/1117-1936.190342

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  Abstract 

Background: Presbyopia is an age-related loss of lens accommodation resulting in difficulty in performing near task with attendant effect on the quality of life.
Objective: The objective of the study was to determine the prevalence of presbyopia and presbyopic spectacle correction coverage among public school teachers in Ifo township, with a view to providing a baseline information that could be useful for advocacy and planning appropriate intervention.
Study Design: The study was a descriptive, cross-sectional study.
Materials and Methods: Six hundred public school teachers aged 30 years and above were examined in 25 clusters using a multistage random sampling technique with probability proportional to size. Questionnaire was used to obtain information on demographic data, sources of spectacle and barriers to spectacle use. All participants underwent a standardised protocol including visual acuity assessment (distance and near acuity), anterior and posterior segment examinations and refraction.
Results: Six hundred teachers were examined with an age range of 30–61 years. The mean age was 44.7 ± 7.5 years and the male to female ratio was 1:2.2. The prevalence of presbyopia was 81.3% and 38.5% of the presbyopic teachers did not have presbyopic correction. However, the average age of onset of presbyopia was earlier in females 33 years compared to 36 years observed in males, although not statistically significant (P = 0.88). The presbyopic correction coverage was 61.5%. One hundred and eighty-six (62%) presbyopic teachers obtained their spectacle from opticians, and the main barriers to the use of near vision spectacle were lack of awareness (23.7%) and cost (13.7%).
Conclusion: This study demonstrated a high prevalence of presbyopia among public school teachers in Ifo town, South-West Nigeria, but less presbyopic spectacle correction coverage.

Keywords: Presbyopia, school teachers, spectacle coverage


How to cite this article:
Idowu OO, Aribaba OT, Onakoya AO, Rotimi-Samuel A, Musa KO, Akinsola FB. Presbyopia and near spectacle correction coverage among public school teachers in Ifo Township, South-West Nigeria. Niger Postgrad Med J 2016;23:132-6

How to cite this URL:
Idowu OO, Aribaba OT, Onakoya AO, Rotimi-Samuel A, Musa KO, Akinsola FB. Presbyopia and near spectacle correction coverage among public school teachers in Ifo Township, South-West Nigeria. Niger Postgrad Med J [serial online] 2016 [cited 2022 Jul 7];23:132-6. Available from: https://www.npmj.org/text.asp?2016/23/3/132/190342


  Introduction Top


Presbyopia is an age-related loss of lens accommodation that results in inability to focus at near distances and can have multiple effects on quality of vision and quality of life.[1] Uncorrected presbyopia results in an inability to perform once-effortless near tasks at a customary working distance with attendant visual symptoms. Presbyopia poses an important public health challenge because its onset coincides with the productive year of an individual which may affect productivity and subsequently hinder economic development of a nation. In 2005, meta-analysis done by Holden et al.[2] estimated that there were 1.04 billion people globally with presbyopia, 517 million of whom had no spectacles or inadequate spectacles. Of these, 410 million were prevented from performing near tasks in the way they required. Thus, as more near transactions are done in reading, writing and use of computers, adults with poor near vision may be at economic disadvantage. Presbyopia has been found to occur earlier in Africans and it is more severe.[3],[4],[5] This informed the use of the age group 30 years and above for this study, and assessment of individuals in this age group would provide an opportunity for detection of potentially blinding eye diseases.

Teachers constitute one of the main building pillars of a sound, competitive and progressive society whose ability to see clearly is important for daily activities. Similarly, an individual's visual skill should match the visual requirement of the tasks he or she needs to perform in order to promote good job performance and productivity. Thus, the visual system must be at its maximum potential to perform necessary near visual task efficiently especially as working condition is different. However, a teacher with uncorrected presbyopia might not perform efficiently as marking of most examination scripts and evaluation of learners work are done manually in Nigeria. The need to read and work at near and intermediate distances is important to this population especially with increasing technological advancement; hence it is imperative to determine the prevalence of presbyopia and presbyopic correction coverage. Therefore, this study is expected to contribute to the need assessment for the correction of presbyopia among teachers and generate baseline information in advocacy, planning and establishing refraction and spectacle distribution for teachers.


  Subjects and Methods Top


This was a descriptive, cross-sectional study conducted among public school teachers 30 years and above over a period of 8 weeks from 26th January 2015 to 20th March 2015. Ethical approval was obtained from the Health Research and Ethics Committee of Lagos University Teaching Hospital (LUTH). The tenets of the Helsinki Declaration were adhered to strictly. Permission was obtained from the Ogun State Ministry of Education, Abeokuta, and Local Government Education Board, Ifo LGA, for this study.

Using Leslie–Kish formula,[6] a minimum sample size of 302 was calculated which was further increased to 620 after making an allowance for 20% attrition and adjusting for a multistage cluster sampling design effect of 1.7. Using average cluster size of 25 teachers, 25 (620/25) clusters of schools were selected using a multistage random sampling with probability proportional to size for the study. The 25 clusters of schools selected comprised 21 primary schools and four secondary schools. All teachers in the 25 selected clusters of schools that met the inclusion criteria were enrolled for the study.

The participants' bio-data comprising of age, sex and educational level were obtained by trained research assistants and entered into the appropriate section of the questionnaire. The distance visual acuity in each eye was tested individually using the Snellen chart in ambient outdoor natural illumination and distance refraction was done using an autorefractor (Xinyuan Model FA 6500) for subjects with visual acuity <6/18 after demonstrating improvement of at least one line when tested with a pinhole. This was followed by subjective refinement using the Snellen chart. Teachers with best-corrected distance visual acuity <6/18 were excluded from the study. The near vision was tested using a near reading chart placed at 40 cm from the eye, measured with a tape measure in ambient light. The distance correction was put in place for those that required it before near vision testing was done. Spherical plus lenses were added in increments of 0.5 dioptres until the subject could read N8 or no further improvement occurred. Presbyopia was defined in an individual as the requirement of near correction of at least +1.00D in either eye in addition to their best distance correction to achieve vision criterion of at least N8 at 40 cm.[7] All refractions were carried out by the Principal Investigator. Free near correction spectacles were provided to the presbyopes (uncorrected or under-corrected), subject to availability of the required power and willingness of participants to accept after full examination of the entire cluster to avoid bias. All participants had pen-torch examination of the adnexa and anterior segments of both eyes including assessment of pupillary reaction. A direct ophthalmoscopy was performed to examine the posterior segment using the Heine direct Ophthalmoscope with no pupil dilation under dark illumination. Participants with ocular abnormality in any of the ocular structures were referred to LUTH Primary Health Centre, Eye clinic, for further evaluation.

The data collected were entered, cleaned and statistically analysed using Epi Info version 6 (CDC, Atlanta, GA, USA). Frequencies, means and standard deviations were generated to observe patterns of variable distribution among participants. Presbyopia correction coverage was calculated using the formula below. Met need was the number of presbyopic participants who already have spectacles while the unmet need was the number of presbyopic participants who require correction without spectacles (previously owned near spectacles which were either lost or broken as well as those who have never worn spectacles).[8]




  Results Top


Six hundred participants were analysed out of 620 participants enumerated for the study. This accounted for 96.8% response rate because twenty teachers were absent during the study period due to illness and maternity leave.

The age range of the teachers was 31–61 years with a mean age of 44.7 ± 7.5 years and majority of the participants were in the age range of 40–49 years (43.7%). There were more female participants 410 (68.4%) than male participants 190 (43.9%), with an overall male to female ratio of 1:2.2. In addition, 356 (59.3%) participants have Bachelor's degree as their highest level of education as shown in [Table 1].
Table 1: Sociodemographic characteristics of the participants (n=600)

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Among the participants, 488 (81.3%) teachers were presbyopic while 112 (18.7%) were non-presbyope. Furthermore, 300 (61.5%) out of the 488 presbyopic participants had near spectacle correction while the remaining 188 (38.5%) had no near spectacle correction. The age range of 40–49 years had the highest participants with presbyopia accounting for 260 (53.3%) out of the 488 presbyopic participants [Table 2]. The overall mean age of presbyopic respondents was 47.0 ± 6.2 years which was lower in female 43.3 ± 4.7 years compared to male 46.3 ± 5.6 years (P = 0.82). The average age of onset of presbyopia was earlier in females 33 years compared to 36 years observed in males, although not statistically significant (P = 0.88).
Table 2: Age, gender and educational distribution of presbyopic participants (n=488)

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The multivariate analysis shown on [Table 3] suggests that increasing age (odd ratio [OR] = 2.37, 95% confidence interval [95% CI] = 1.58–3.56) and female gender (OR = 3.42, 95% CI = 1.65–6.10) were significantly associated with higher prevalence of presbyopia. The PCC for this study was calculated to be 61.5% from a met need of 50.0% (300) and an unmet need of 31.3% (188). [Table 4] shows that 186 (62%) of the 300 corrected presbyopic participants obtained their glasses from optician/optometrist while 23.7% of presbyope not using spectacles were not aware of any problem as shown in [Table 5].
Table 3: Multivariate model of risk factors for presbyopia

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Table 4: Sources of spectacle among presbyopic participants using glasses

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Table 5: Barriers to the use of near vision (presbyopic) spectacle among non-users

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  Discussion Top


The average age of onset of presbyopia in this study was 34 years. This is contrary to the studies among teachers in Onitsha [9] and Kolokuma/Opokuma,[10] where the average age of onset was 38 years and 37 years, respectively. The case definition of presbyopia used in Onitsha and Kolokuma/Opokuma studies using amplitude of accommodation equal to or <4 dioptres may be responsible for this disparity. However, our finding supports previous studies by Adefule and Valli [5] and Nwosu [11] that presbyopia occurs earlier in Africans and literate population.

In this study, the prevalence of presbyopia was 81.3%. This is comparable to the findings of a study conducted in Onitsha [9] (79.1%) but higher than the prevalence reported in Ghana [12] (68.1%) and Jakarta [13] (66.4%). The criterion of the distance of 30 cm used to achieve at least N8 optotype in Ghana and Jakarta studies may explain this disparity, whereas we used 40 cm in our study. However, the magnitude of uncorrected presbyopia of 38.5% in this study is fairly comparable to the value obtained in Jakarta [13] (41.0%) but higher than the Ghana [12] study (29.6%). In Ghana, teachers aged 40 years and above were studied while our study examined teachers 30 years and above. This age difference may account for the difference in the magnitude of uncorrected presbyopia compared to our study.

Presbyopia was significantly associated with increasing age and female gender in this study (P < 0.001). The presbyopia prevalence of 65.5% among females in this study was significantly higher than 34.5% documented for males. Similarly, the results of other studies in Tanzania,[3] India,[7] and Kenya [14] showed that presbyopia was more prevalent in women. The results of meta-analysis of cross-sectional studies by Hickenbotham et al.[15] also showed an increased prevalence in women but the difference was not physiologic in nature but had been attributed to other factors such as preferred reading distances, such as arm length, occupation, indoor light levels and specific conditions related to desired tasks.

This study found PCC of 61.5%, a met need of 50.0% and an unmet need of 31.3% which is different from the study conducted in Abuja [16] that found PCC of 21.0%, a met need of 11.2% and an unmet need of 42.1%. This finding corroborates the previous studies of Muhammad et al.[16] and Ramke et al.[17] that found significantly higher PCC among literate population in which the study population belongs. However, the study conducted in Abuja was not among teachers which may account for the disparity in PCC.

Sixty-two per cent of the presbyopic participants in this study obtained their spectacle from optometrists or opticians compared to 93% of presbyopes in the Andhra Pradesh study [6] that obtained their spectacle from ophthalmologist in a mixed urban-rural population. This is in contrary to the findings in rural China [18] where 75%–90% of the population source for presbyopic corrections in the market. Although our study area has a significant rural population, the literacy level of the study population may explain the difference in the source of presbyopic spectacles compared to the rural Chinese population.

The main barriers to the use of near vision spectacles were lack of awareness (23.7%) and cost (13.7%) in this study. However, the study in Abuja [16] documented lack of money (51.8%) and spectacle not being a priority (19.7%) as major barrier to near vision correction whereas financial barriers (30.6%) and spectacle not being a priority (33%) appeared to be most important in Zanzibar.[8] In Abuja and Zanzibar, lack of money was a common barrier to the use of near vision spectacle which is similar to our finding, but lack of awareness of presbyopic symptoms in this present study may be due to the rural population of the study area. These findings make it imperative that spectacles should be affordable to increase near vision spectacle coverage, especially in a community like Ifo township where a significant proportion of the local population may be living below the poverty line.

The non-consideration of the pregnancy status of the female participants, which may be a confounding factor, was a limitation of this study.


  Conclusion Top


This study has demonstrated a high prevalence of presbyopia among teachers in public schools in Ifo township, South-West Nigeria, with non-commensurate PCC attributable to lack of awareness of the problem and affordability. This indicates that there is a need for better access to refractive services and spectacles. These findings could serve as baseline information in advocacy, planning and establishing refraction services and spectacle distribution for teachers. A larger study in this regard with better external validity is also recommended.

Acknowledgement

We thank the Ogun State Ministry of Education, Ifo Local Government Education Authority, Principals and Head teachers for their support. We also want to show our appreciation to Project 20/20 Eyeglasses Recycling Center that donated free spectacle for this project work.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

1.
Michaels DD. Visual Optics and Refraction: A Clinical Approach. 3rd ed. St. Louis, Missouri: CV Mosby; 1985. p. 419-22.  Back to cited text no. 1
    
2.
Holden BA, Fricke TR, Ho SM, Wong R, Schlenther G, Cronje S, et al. Global vision impairment due to uncorrected Presbyopia. Arch Ophthalmol 2008;126:1731-9.  Back to cited text no. 2
    
3.
Burke AG, Patel I, Munoz B, Kayongoya A, McHiwa W, Schwarzwalder AW, et al. Population-based study of presbyopia in rural Tanzania. Ophthalmology 2006;113:723-7.  Back to cited text no. 3
    
4.
Resnikoff S, Pascolini D, Mariotti SP, Pokharel GP. Global magnitude of visual impairment caused by uncorrected refractive errors in 2004. Bull World Health Organ 2008;86:63-70.  Back to cited text no. 4
    
5.
Adefule AO, Valli NA. Presbyopia in Nigerians. East Afr Med J 1983;60:766-72.  Back to cited text no. 5
    
6.
Araoye MO. Research Methodology with Statistics for Health and Social Sciences. Ilorin, Nigeria: Nathadex Publishers; 2003. p. 128.  Back to cited text no. 6
    
7.
Nirmalan PK, Krishnaiah S, Shamanna BR, Rao GN, Thomas R. A population-based assessment of presbyopia in the state of Andhra Pradesh, South India: The Andhra Pradesh eye disease study. Invest Ophthalmol Vis Sci 2006;47:2324-8.  Back to cited text no. 7
    
8.
Laviers H. The prevalence of presbyopia and the feasibility of community distribution of near spectacles in adults in Zanzibar, East Africa. Community Eye Health 2007;20:73.  Back to cited text no. 8
    
9.
Anajekwu C. Vision Survey of Secondary School Teachers' in Onitsha, Nigeria. Dissertation Submitted to National Postgraduate Medical College of Nigeria; May, 2011.  Back to cited text no. 9
    
10.
Ichenwo TJ. Refractive Status among Teachers' in Kolokuma/Opokuma LGA, Bayelsa, Nigeria. Dissertation Submitted to National Postgraduate Medical College of Nigeria; May, 2009.  Back to cited text no. 10
    
11.
Nwosu SN. Presbyopia in Anambra State, Nigeria. Niger Med J 2001;40:7-9.  Back to cited text no. 11
    
12.
Kumah DB, Lartey SY, Amoah-Duah K. Presbyopia among public senior high school teachers in the Kumasi metropolis. Ghana Med J 2011;45:27-30.  Back to cited text no. 12
    
13.
Ehrlich JR, Laoh A, Kourgialis N, Prasetyanti W, Zakiyah R, Faillace S, et al. Uncorrected refractive error and presbyopia among junior high school teachers in Jakarta, Indonesia. Ophthalmic Epidemiol 2013;20:369-74.  Back to cited text no. 13
    
14.
Sherwin JC, Keeffe JE, Kuper H, Islam FM, Muller A, Mathenge W. Functional presbyopia in a rural Kenyan population: The unmet presbyopic need. Clin Experiment Ophthalmol 2008;36:245-51.  Back to cited text no. 14
    
15.
Hickenbotham A, Roorda A, Steinmaus C, Glasser A. Meta-analysis of sex differences in presbyopia. Invest Ophthalmol Vis Sci 2012;53:3215-20.  Back to cited text no. 15
    
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Muhammad RC, Jamda MA, Langnap L. Prevalence of presbyopia in rural Abuja, Nigeria. Ann Niger Med 2015;9:56-60.  Back to cited text no. 16
    
17.
Ramke J, Brian G, Naduvilath T. Refractive error and presbyopia in timor-leste: The impact of 5 years of a national spectacle program. Invest Ophthalmol Vis Sci 2012;53:434-9.  Back to cited text no. 17
    
18.
Lu Q, He W, Murthy GV, He X, Congdon N, Zhang L, et al. Presbyopia and near-vision impairment in rural Northern China. Invest Ophthalmol Vis Sci 2011;52:2300-5.  Back to cited text no. 18
    



 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5]


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