|Year : 2013 | Volume
| Issue : 2 | Page : 151-155
Presbyopia in plateau state, Nigeria: A hospital study
Keziah N Malu
Department of Ophthalmology, Benue State University Teaching Hospital, Makurdi, Benue State, Nigeria
|Date of Web Publication||24-Dec-2013|
Keziah N Malu
Department of Ophthalmology, Benue State University Teaching Hospital, Makurdi, Benue State, PMB 102131 Makurdi
Source of Support: None, Conflict of Interest: None
Presbyopia is a refractive error (RE) that causes near visual impairment with advancing age. Uncorrected presbyopia significantly affects near vision-related quality of life of individuals who depend on near work for livelihood, be they literate or illiterate. This study is aimed at finding the prevalence of presbyopia in patients who presented with refractive error in Adoose specialist hospital, Jos.
Materials and Methods: Records of all patients who presented at the hospital from 2000 to 2009 with symptoms of functional presbyopia, defined as requiring at least + 0.75 dioptre in order to read the N8 optotype at a distance of 40 cm in the patient's usual visual state were included in the study. The eye with the better presenting visual acuity was used for classifying the patients.
Results: There were 912 patients with RE. Of these, there were 482 (52.9%) subjects whose visual acuities improved to N8 optotype at a distance of 40 cm with refraction.
There were 265 (55%) males and 217 (45%) females. The mean age of patients at presentation was 47.8 ± 8.2 (range 35-80) years. Most of the patients (77.1%) complained of problems with near visual tasks. Seventy-five (15.7%) subjects presented with glasses of inappropriate corrections that was causing visual strains.
Presbyopia showed a significant increase with increasing age. The power ranged from +0.75 to +4.0D (with a mean of 2.08). The most frequent power was +2.0D.
The civil servants 257 (53.3%) formed the highest number of subjects seeking presbyopic correction.
Plano-presbyopia was the commonest presentation at 51.6% and it showed a significant decrease with increasing age. This was followed by hypermetropia − presbyopia at 32.6% which increased with the increasing age. There were fewer subjects (15.8%) with myopia-presbyopia.
Conclusion: This study has shown that presbyopia presents early and is a problem in our society. Economic consequences are likely to be considerable, as uncorrected presbyopia affects people in the working-age group.
Keywords: Age-related, early onset, gender bias, presbyopia
|How to cite this article:|
Malu KN. Presbyopia in plateau state, Nigeria: A hospital study. J Med Trop 2013;15:151-5
| Introduction|| |
Presbyopia is a result of a physiological change in the crystalline lens of an adult eye, with consequent progressive loss of the amplitude of accommodation, resulting in inability to focus at the near distance, the eye had hitherto been accustomed to.  It is recognized that good near vision is needed for a lot of visual tasks such as sewing, picking stones from rice, wood carving apart from reading, and writing. Presbyopia is therefore receiving global attention as part of refractive error that causes near visual impairment with advancing age. ,,
It starts around at adolescence but usually becomes manifested between 40 and 45 years, and occurs much earlier in females than males. ,,, It is also said to be more severe in females. It is present in 31% of the total population, reaching to about 100% by the age of 52 years.  With the enormity of the problem of RE, there has been urgent call for research studies on the presbyopic aspect of the RE so as to ensure that everyone who needed help got it. 
Studies carried out show that the impact of presbyopia on adult life is enormous. , The Tanzania study looked at the issues of presbyopia and quality of life and noted uncorrected presbyopia significantly affected near vision-related quality of life and suggested the WHO's Vision 2020 initiative placed a greater emphasis on presbyopia.  With the growing number of the aging population in the developing countries, emphasis need to be placed on this correctable cause of visual impairment.
While various methods of correction of presbyopia, such as surgery, intraocular lens implants, and contact lenses in various forms are used in more developed societies, ,,, spectacles in the form of convex single vision lens and bifocal or progressive lenses is the mainstay in developing societies.  Uncorrected or undercorrected presbyopia leads to many adults facing vocational limitations and families frequently being pushed into a cycle of deepening poverty because of their poor near vision. 
Few studies have been carried out on presbyopia in Nigeria. ,,,,, This study aims at finding the prevalence of presbyopia in patients who presented with refractive error in Adoose specialist hospital Jos. To my knowledge, this type of study has not been carried out in this part of the country before, so this study will help inform the policy makers on the burden of presbyopia and will help in planning eye-care programmes.
| Materials and Methods|| |
This is a hospital-based study of eye patients with impaired near visual acuity that improved with refraction. Records of all consecutive patients who presented at the hospital from 2000 to 2009 with symptoms of functional presbyopia, defined as requiring at least +0.75 dioptre correction in order to read the N8 optotype at a distance of 40 cm in the patient's usual visual state, were included in the study. Near vision was corrected to the nearest 0.25 dioptre in order to see N8. Patients with distant refractive errors were corrected for distant vision before being corrected for the near.
The eye with the better presenting distant visual acuity was used for classifying the patients. The formula sphere plus cylinder/2 was used to determine spherical equivalent refraction (SER). The patients' demographic information such as age, sex, ethnic group, occupation, and address were retrieved from the records. The patients' complaints of difficulty with near visual tasks, history of use of spectacles that became weak, examination findings, including best corrected visual acuity, and diagnosis were also retrieved.
The distant visual acuity (VA) was determined using a Snellen lettered chart for literate and the tumbling ''E'' chart for the illiterate. Nurses took the distant vision while the ophthalmologist carried out the objective and subjective refraction.
A pen torch and slit lamp (Marco 11B serial no. 2999422) were used for anterior segment examination while a direct ophthalmoscope (Keeler Standard Otoscope Ophthalmoscope wall unit set 3.6V) and indirect ophthalmoscope (Keller's wired indirect ophthalmoscope) for posterior segment with mydriasis (tropicamide 1%) were carried out where necessary.
The patients were given glasses as per their best-corrected visual acuity for distant and near vision.
Statistical analyses were carried out using SPSS version 17.0 software (SPSS Inc. Chicago, IL, USA). Chi-square test was used to calculate difference between percentages and t-test was used to calculate the difference between means. P <0.05 was considered to be statistically significant.
The permission for the study was obtained from the management of Adoose Specialist Hospital Jos, and there were no ethical issues involved since data were already available and no patient was identifiable.
| Results|| |
A total of 912 patients presented with various types of refractive errors. Out of those with RE there were 482 (52.9%) subjects whose visual acuities improved to N8 optotype at a distant of 40 cm with refraction.
These were 265 (55%) males and 217 (45%) females. The mean age of patients was 47.8 ± 8.2 (range 35-80) years.
Most patients 372 (77.1%) complained of problems with near visual tasks such as inability to read fine prints, not being able to thread a needle, ocular pains while reading. There were 75 (15.7%) subjects who were presented with glasses of inappropriate corrections that were causing visual strains. Other ocular problems complained of by subjects included watering 119 (24.6%), photosensitivity 16 (16.5%), and pains 29 (6.0%).
[Table 1] shows the presenting symptoms of patients with presbyopia.
Presbyopia showed a significantly increased severity with increasing age (P < 0.001). While presbyopia of +0.75 to +1.50D was commonest in the 35-40 year group, higher degrees were commoner in older age groups. [Figure 1] shows the age categories of the 482 subjects with presbyopia.
There was increasing degree of presbyopia with age in both sexes, and no statistically significance difference between sexes (P > 0.05). [Table 2] shows age, sex and severity of presbyopia amongst the patients.
The occupation of the subjects was significantly related to the ability to seek presbyopic correction as seen in [Table 3]. The civil servants 257 (53.3%) formed the highest number of subjects seeking presbyopic correction with 50.2% requiring addition power between +1.75 and 2.25D.
The powers between +1.75 to +2.25D were the commonest correction seen within all refraction types. There were more subjects with plano-presbyopia 249 (51.6%) followed by hypermetropia with presbyopia 157 (32.6%) and least myopia with presbyopia 76 (15.8%). [Table 4] shows various refractive error type and the power additions.
The SER ranged from -7.0 to +4.38D (mean of 0.16).
Plano-presbyopia showed a decrease with the increase in age. It decreased from 62 (72.9%) in age group 35-40 years to 4 (12.5%) among age group 61-70 years. This was statistically significant P < 0.001. In the same vein hypermetropia-presbyopia showed a significant increase with the increase in age, increasing from 13 (15.3%) in age group 35-40 to 21 (65.6%) in the age group 61-70 years. [Table 5] shows the relationship between refractive error type and age category.
| Discussion|| |
Of the 482 patients, 77.1% presented with problems related to near visual tasks such as reading and sewing. Some presented with glasses of inappropriate corrections that were causing visual strains. Other ocular complaints included watering, photosensitivity, and pains. Studies have shown that presbyopia affects all life issues related to near vision. ,
The prevalence of presbyopia in the present study was 482 (52.9%) of the patients with RE. This compares with Bagaiya et al.,  56% in the Northern Nigeria but was higher than 31.8% reported for Southwest Nigeria  and 12.8% in Yenagoa, Bayelsa State of Nigeria.  Abah et al. in a University community in Zaria, North West Nigeria found presbyopia in 49.7% of those above 40 years.  In the sample populations studied; it would appear that more patients with presbyopia present in northern parts of Nigeria than the south.
In this study, there was a wide age range at presentation of 35 to 80 years. Among these, 11.7% constituted of people aged 35-39 years. Previous hospital and population based studies in Nigeria and elsewhere in Africa ,,,,, and Asia  also found an earlier presentation of presbyopia, in contrast to the Caucasians where it becomes manifest about mid-40s.  This pattern has been documented in the earlier descriptions of presbyopia in tropical and temperate regions. , Ezepue in Eastern Nigeria determined the average age of onset to be about 40 years.  Interestingly, a study carried out in Bayelsa State,  detected presbyopia in an even younger population of 30-34 year olds! The study however did not indicate whether those who had presbyopia were also hypermetropic or not.
In this study presbyopia showed a significant increase in severity with increasing age (P = 0.001). It increased from + 0.74 in 35-39 year olds to + 3.0 D and above in those 70 years and above. This observable trend is said to be due to the age-related progressive decline in the amplitude of accommodation, as a result of physiological changes in the crystalline lens. 
The study also showed more males had higher degree of presbyopia, but the difference was not statistically significant. This is similar to the finding in Bayelsa State of Nigeria  and Ezepue in Eastern Nigeria  but in contrast to previous studies elsewhere that found females requiring a power of greater magnitude than their age-matched male counterparts. ,,,, The studies however did not show a relationship between presbyopia and hypermetropia. Nirmalan et al.  in an Indian population-based study found the women had 40% higher odds of being presbyopic, and the prevalence increased with age. Duarte et al. in Brazil also showed age and female sex to be associated with higher prevalence of presbyopia. In a study in Tanzania, Burke et al. found women had 46% higher odds of being presbyopic and also had more severe presbyopia than men across all age groups.  The reason for presbyopia being commoner and severer among the males in the Nigerian studies is not clear; it may require further investigation and research.
The civil servants formed the highest number of subjects seeking refractive services followed by the business people, house wives, and the clergy. This was not surprising since these groups tend to have greater access to health care and undertake visually related tasks in which problems of vision are readily discernable.
The most frequent power required was +2.0D followed by +2.25D and 2.50D. This could be related to the fact that there were more people in this age group of 50-55 years seeking presbyopic correction. As described in previous studies conducted in Nigeria, , most of the patients had plano-presbyopia, followed by hypermetropia with presbyopia and least of all, myopia with presbyopia. Plano-presbyopia showed a statistically significant decrease with the increase in age. It decreased from 72.9% in age group 35-40 years to 12.5% among age group 61-70 years. On the contrary hypermetropia-presbyopia showed a significant increase with increase in age, increasing from 15.3% in age group 35-40 to 65.6% in the age group 61-70 years.
| Conclusion|| |
This study has shown that presbyopia presents early and is a problem that cuts across our society and impacts visually related tasks both in the formal work place and among artisans such as tailors. Economic consequences are likely to be considerable, as uncorrected presbyopia affects people in the working-age group.
There was no statistically significant difference noted between sexes in both the frequency and the degree of presbyopia in this group of patients.
Spectacles correction for presbyopia is an effective option for our society. Efforts should be aimed at monitoring and eliminating this avoidable cause of visual impairment by providing low cost but quality spectacles with power within the ranges of the common errors detected. There is a role for screening people in the early 40s and above for presbyopia and correction.
| Acknowledgement|| |
I am profoundly grateful to Prof AO Malu for proof reading this manuscript and offering constructive suggestions.
The management of Adoose Specialist Hospital allowed access and use of their patients' records. I feel indebted to them.
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]