Pattern of Ocular Conditions among Patients Attending an Eye Clinic in Ghana

Ocular diseases affect every individual in this world, with the only difference being in the pattern of occurrence of disease depending on age, gender, region, and climatic conditions. The pattern of eye diseases and causes of blindness in developing and developed countries and often in different communities vary [1]. The majority of these ocular conditions which can lead to blindness are either potentially preventable or curable.

Numerous studies on the pattern of ocular conditions in developed countries have been conducted. Information is however scanty about the extent of ocular morbidity in developing countries, particularly for non-vision impairing conditions (NVIC), although these constitute the majority of consultations in eye clinics [2,3].

The Wiamoase community of Ashanti Region is a typical rural farming community that contributes to a significant percentage of Ghana?s vegetable and other crop production. Rural communities and healthcare facilities have limited resources to address many health-related needs. It is necessary for a research to be done to investigate the pattern of ocular conditions among people in the community in order to provide a substantive guide for policy makers on the intervention programmes and projects to be carried out in the community to help improve the eye health of the people.

A prospective cross-sectional study involving 1000 randomly selected subjects attending the Salvation Army Eye Clinic in Wiamoase in 2016 was done. Wiamoase is a town 71.7 km from Kumasi, the capital city of the Ashanti Region of Ghana.

The sample size was calculated using the formula: n=Z²p(1-p)/d²

Where:

p? is the assumed population proportion=0.7

d? is the margin of error=0.03

With a (CI) confidence interval of 95% ?Z?=1.96

n=1.96² x 0.7(1-0.7)/0.03² = 897

10/100 x 897=90

Minimum sample size=987 participants. 1000 participants were involved.

Informed consent was obtained from all subjects after the procedure and aim of the study was described to them. Subjects were also told they could withdraw from the study at any time. Multiple visits of participants were not included in the study. Participants were captured only once. The study was approved by the Ethics and Research committees of the Salvation Army Eye Clinic and the Department of Optometry and Visual Science, Kwame Nkrumah University of Science and Technology, and was carried out in accordance with the tenets of the declaration of Helsinki.

The demographic data such as age and gender of the patients were recorded in a simple recording form that was developed. Detailed ocular examination was done. Distant visual acuity (VA) was measured using the Snellen?s VA chart at 6 m. Patients with poor VA (<6/9) underwent a pinhole vision to differentiate refractive errors from pathological conditions. Refractive error was diagnosed when a VA worse than 6/9 improved on pinhole test. Bruckner test was performed to detect refractive errors in children less than 5 years. Examination of the eyelid margins, conjunctivae, the cornea and anterior segment of the eye was performed with the aid of a slit lamp, pentorch and a magnifying loupe. Hirschberg test and coveruncover test were also carried out to diagnose strabismus and latent squint. Posterior segment examination was performed after dilating pupil with 0.5% mydriacyl using direct and indirect ophthalmoscope and fundus contact lenses. Refraction was performed routinely under cycloplegia. The diagnosis arrived at was also recorded.

Data analysis was performed using SPSS version 23.0 (IBM Corporation, Armonk, NY, USA). Results were summarised and presented as tables and chi square test was used for test of association. For all statistical tests, the decision was significant if the p-value is < 0.05. Statistical analyses like frequency, cross tab were used to describe most of the findings.

The ages of patients ranged from 1 week to 110 yrs with a mean age of 45.99 yrs (SD=± 27.69). The ages of male patients ranged from 1 month to 110 yrs with a mean of 39.27.

Years (SD=± 27.85) whereas the female patients had ages from 1 week to 98 yrs with a mean of 50.15 yrs (SD=± 26.77). There were 382 males (38.20%) and 618 females (61.80%) with a male to female ratio of 1:1.6. Twenty-six point three per cent (26.30%) of the patients were 20 years and below, 17.60% were aged from 21 to 40 years and 56.10% were above 40 years. Table 1 show the age and gender distribution of the patients seen.

Table 1: Age and gender distribution of the patients.

The commonest eye disorder encountered was conjunctivitis (39.70%). This was followed by cataract (24.40%), glaucoma (9.70%) and refractive errors (8.90%). There was no abnormality in 2.00% of the patients. 96.72% of cases of cataract and 85.57% of cases of glaucoma occurred in those above 40 years. Of those with refractive error, there were 40.45% with myopia, 34.83% with astigmatism and 24.72% with hyperopia.

Table 2 shows pattern of ocular diseases. Conjunctivitis and cataract were significantly higher in females with p values of 0.008 and 0.000 respectively using the chi square test. However, there was no significant difference in the prevalence of glaucoma and refractive errors between males and females with p values of 0.189 and 0.255 respectively. Presbyopia was significantly higher in males with p values of 0.017.

Table 2: Pattern of ocular conditions.

Among the males, the most predominant ocular condition diagnosed was conjunctivitis (45.03%) followed by cataract (15.97%), refractive error (10.21%), glaucoma (8.12%) and keratitis (3.66%). There was no abnormality in 2.36% of the male patients.

Similar trend was found among the female patients. The commonest ocular condition among the females was conjunctivitis (36.41%). This was followed by cataract (29.62%), glaucoma (10.68%), refractive error (8.09%) and keratitis (2.10%). 1.78% of the female patients had no abnormality. Table 3 shows the cross tabulation of ocular condition and gender.

Table 3: Cross tabulation of ocular conditions and gender.

In young patients 20 yrs and below, the commonest eye disorders were conjunctivitis (71.86%) and refractive error (9.51%). There was no abnormality in 6.84% of these young patients. In adults above 20 yrs, the commonest eye disorders were cataract (32.84%), conjunctivitis (28.22%), glaucoma (12.62%), refractive error (8.68%), keratitis (2.85%), pterygium (2.58%) and presbyopia (2.17%).

Tables 4, 5 and 6 show the age distribution of the eye disorders seen. Conditions that were in very small frequencies are grouped as “Other”. They include: dislocated lens, nystagmus, pinguecula, posterior uveitis, prosthetic eye, ptosis, subconjunctival haemorrhage and toxoplasmosis. Patients below 21 years were classified as young ones, those between 21 and 60 as adults and above 60 as seniors.

Table 4: Age distribution of ocular conditions.

Table 5: Age distribution of ocular conditions.

Table 6: Age distribution of ocular conditions.

Majority of eyes (45.33%) had presenting visual acuity better than 6/18, 39.00% had visual acuity between 6/60-6/18 while 15.67% had visual acuity worse than 6/60. 200 eyes (10.00%) had no visual acuity recorded for them.

In the right eye, 44.26% had presenting visual acuity better than 6/18, 40.73% had visual acuity between 6/60-6/18 while 15.01% had visual acuity worse than 6/60. 94 eyes (9.40%) had no visual acuity recorded for them.

In the left eye, 46.42% had presenting visual acuity better than 6/18, 37.25% had visual acuity between 6/60-6/18 while 16.33% had visual acuity worse than 6/60. 106 eyes (10.60%) had no visual acuity recorded for them.

The study shows that females (61.8%) were more in attendance than males (38.2%) at the eye clinic. This is because of the proximity of the centre to their homes, which enables the females to seek medical help on their own without being dependent on their spouses or other family members.

A similar study by Adeoye and Omotoye [4] in south west Nigeria reported a female preponderance. Similar results showing a female preponderance was also seen in the National Blindness Survey conducted by Brilliant et al. [5], where the survey took place at the rural areas thereby enabling the females for easy access to eye care services. This is different from most hospital based studies where there is a male preponderance [6-8].

More adults had ocular problems in this study than children. Ajaiyeoba [9] reported a similar trend though the difference observed in his study was not statistically significant. A likely explanation for this is that children may not be able to adequately articulate their problems and hence may not present to the hospital until the features are prominent enough to be noticed by their parents or guardians.

Conjunctivitis was the commonest ocular morbidity accounting for 39.70%, followed by cataract (24.40%), glaucoma (9.70%) and refractive errors (8.90%). Conjunctivitis was the commonest ocular morbidity in a similar study by Adenuga and Samuel [4] with a prevalence of 42%. Other studies reported it as the third leading cause of ocular morbidity with prevalence of less than 20% [4,10-12]. Kumah et al. [13] in their study reported it as the condition with the second highest prevalence.

It was also the major cause of eye disease in the paediatric age group in this series. This agrees with other hospital based studies as well as school eye health surveys that have also reported it as either the commonest [8,9,14-16] or the second most common [2,7,10] cause of eye disease in children. Conjunctivitis was significantly higher in females (p=0.008). The reason for gender-related difference is not certain but could be due to the relative differences in response to health seeking behaviour.

Cataract and glaucoma had prevalence of 24.40% and 9.70% respectively in this series. Similarly, Adeoye and Omotoye [4] reported figures of 26% for cataract and 10.9% for glaucoma in a study in south west Nigeria. Amadi et al. [12] however reported less than 5% for both disease conditions. This difference may due to the fact that their study had a mean age of 30.5 years while the mean age for this study was 45.99 years.

Both disease conditions are commoner with increasing age and in this study the prevalence was statistically greater in those aged 40 yrs and above. Cataract was significantly higher in females (p=0.000). As elsewhere, females have slightly higher rates of cataract incidence for reasons that are not completely known. However, there was no significant difference in the prevalence of glaucoma between males and females (p=0.189). Uncorrected refractive errors constitute important ocular health problems across the globe [17,18]. It has impact on quality of life, and has educational and socioeconomic consequences. In this present study it was the fourth commonest cause of ocular morbidity with a prevalence of 8.90%.

Similar studies reported refractive error as the third [6,19], second [4] and commonest [11,17,20] cause of ocular morbidity. In a study by Kumah et al. [13] in Ghana, the most prevalent condition was refractive error (26.30%).

The low prevalence of refractive error in this study could be attributed to ignorance as some patients fail to complain of poor vision to eye care providers because of negative perception about spectacle wear and the cost involved in getting one. No significant difference was noticed in refractive error due to gender (p=0.255). This is in agreement with previous report by Iakho and Mohamed Ali [19].

In the present study myopia was the most common refractive error seen among the patients. This was followed by astigmatism and then hyperopia. This agrees with the previous clinical studies in Nigeria, which show that myopia is the most common refractive cause of visual impairment [3,5]. However, Ayanniyi et al. [13,14] in a private optometry practice in AdoEkiti Nigeria and Bagaiya and Pam [16] in Kaduna State North Central Nigeria among University community both found hyperopia to be the commonest refractive error.

This hospital based study however agrees with other studies in Africa and among black Africans who found myopia as the commonest refractive error, but at a lower prevalence than what is seen among the European and South East Asian Nations. The prevalence of myopia is on the increase worldwide and especially in the South East Asian countries [21-24].

75% of those diagnosed of presbyopia in this study were above 40 years. The youngest age of presentation of 30 years in this study compares with 32 years reported by Adenuga and Samuel and 33 years reported by Bernice and Emmanuel [18]. Ayanniyi et al. [13,14] in a similar study also reported the youngest age of presentation of 30 years. Africans Uncorrected refractive errors constitute important ocular health problems across the globe [22]. It has impact on quality of life, and has educational and socioeconomic consequences. In this present study it was the fourth commonest cause of ocular morbidity with a prevalence of 8.90%.

Similar studies reported refractive error as the third [4,19], second [4] and commonest [11,17,20] cause of ocular morbidity. In a study by Kumah et al. [13] in Ghana, the most prevalent condition was refractive error (26.30%).

The low prevalence of refractive error in this study could be attributed to ignorance as some patients fail to complain of poor vision to eye care providers because of negative perception about spectacle wear and the cost involved in getting one. No significant difference was noticed in refractive error due to gender (p=0.255). This is in agreement with previous report by Iakho and Mohamed Ali [19].

In the present study myopia was the most common refractive error seen among the patients. This was followed by astigmatism and then hyperopia. This agrees with the previous clinical studies in Nigeria, which show that myopia is the most common refractive cause of visual impairment [3,5]. However, Ayanniyi et al. [13,14] in a private optometry practice in AdoEkiti Nigeria and Bagaiya and Pam [16] in Kaduna State North Central Nigeria among University community both found hyperopia to be the commonest refractive error.

This hospital based study however agrees with other studies in Africa and among black Africans who found myopia as the commonest refractive error, but at a lower prevalence than what is seen among the European and South East Asian Nations. The prevalence of myopia is on the increase worldwide and especially in the South East Asian countries [25-28].

75% of those diagnosed of presbyopia in this study were above 40 years. The youngest age of presentation of 30 years in this study compares with 32 years reported by Adenuga and Samuel [4] and 33 years reported by Bernice and Emmanuel [18]. Ayanniyi et al. [13,14] in a similar study also reported the youngest age of presentation of 30 years. Africans Presbyopia was significantly higher in males than females (p=0.017). It could be that males do more near work than females in the study area. This is in agreement with previous report by Iakho and Mohamed Ali [19]. A female preponderance for presbyopia was observed in studies by Patel and West [29-33], Ayanniyi et al. [13,14] and Adenuga and Samuel [4].

Majority of eyes (45.33%) had presenting visual acuity better than 6/18, 39.00% had visual acuity between 6/60-6/18 while 15.67% had visual acuity worse than 6/60. Comparable study by Waziri-Erameh and Omoti [34-39] reported similar findings with majority of patients (70.18%) with visual acuity better than 6/18, 25.49% with visual acuity between 6/60-6/18 while 4.33% had visual acuity worse than 6/60.

However, one study by Hassan et al. [40-45] reported higher percentage of patients with visual acuity between 6/60-6/18 (46.34%) followed by visual acuity better than 6/18 (39.84%) and then visual acuity worse than 6/60 (13.82%). The higher case of satisfactory visual acuity (better than 6/18) could be a reason for the low prevalence of refractive error in this study.

In conclusion, the leading causes of eye disease in this study were conjunctivitis, cataract, glaucoma and refractive errors. There were more female in attendance than males. The pattern of ocular disorders observed in this study is similar to the findings from other parts of the developing world in spite of variability of methods for calculating causes. This type of study is helpful to have idea about the epidemiology of any ocular disorder.

It is necessary to organize community education and ensure early treatment to reduce the prevalence of these diseases in the general population. A more extensive survey would help in generating the updated information about the status of ocular morbidity in the community in general and the prevalence of blindness in particular. Health education programs should target older age groups specifically and the population in general. The availability and accessibility of eye care services, particularly cataract surgery and refraction services should be increased.