Ejimadu CS; Chinawa NE; Fiebai B

Research Article

Austin J Clin Ophthalmol. 2018; 5(2): 1092.

Age and Gender Related Changes in Intraocular Pressure among Patients Attending a Peripheral Eye Clinic in Port Harcourt, Nigeria

Ejimadu CS¹, Chinawa NE² and Fiebai B¹*

¹University of Port Harcourt Teaching Hospital, Nigeria

²Mercy Eye Hospital, Abak, Nigeria

*Corresponding author: Fiebai B, Department of Ophthalmology, University of Port Harcourt Teaching Hospital, Port Harcourt, Rivers State, Nigeria

Received: March 20, 2018; Accepted: April 17, 2018; Published: April 24, 2018

Abstract

Purpose: To determine the age and gender related changes in intraocular pressure among patients attending a private eye clinic in Port Harcourt Nigeria.

Methods: This was a cross sectional study done in a private hospital in Port Harcourt. The first one hundred patients attending the hospital in 2013 and met the inclusion criteria were recruited for the study. Those with corneal diseases/ lesions were excluded. Age and sex were obtained from the patient’s history while intraocular pressure (IOP) was measured using Perkins applanation tonometer (MK2 Model). Intraocular measurements were taken between 9am and 12pm.

Results: There were 100 subjects in this study comprising 59 males and 41 females (M: F=3:2). The mean age was 45.83±20.43years. The mean IOP was 16.18±6.13 for right eye and 16.82±8.22 mmHg for left eye.

IOP was higher in right and left male eyes compared to females but these were not statistically significant (p-value = 0.133 for right eye and; p-value = 0.267 for left eye). There was a weak positive correlation between right eye IOP and age (r=0142; p-value=0.174) and left eye IOP and age (r=0.202; p-value=0.0505). There was fluctuation of IOP in different age groups.

Conclusions: There was no statistical significance difference in IOP in both genders. There is a weak positive correlation between IOP and age.

Keywords: Age; Gender; Glaucoma; Intra Ocular Pressure

Abbreviations

ANOVA: Analysis of Variance; IOP: Intraocular pressure; S.D: Standard deviation

Introduction

Intraocular pressure (IOP) is the fluid pressure inside the eye. Elevated intraocular pressure is a major risk factor for the development of primary open-angle glaucoma [1], and even in normal tension glaucoma the reduction of IOP may slow the progression of visual field loss [2]. It is the only proven treatable risk factor. People with a high IOP with no proof of having primary open-angle glaucoma are considered at risk of developing optic nerve damage, even if they do not suffer from any ocular disease [3].

Numerous factors have been known to influence IOP. These include age and sex. IOP distribution and associated ocular features and its correlation with age are of clinical interest. The relationship between IOP and age varies in different ethnicities. Studies conducted in Western countries [4,5] Iran [6], and Barbados [7] show a positive correlation between IOP and age. On the contrary, most of the East Asia studies reported a negative correlation between IOP and increasing age [8,9]. Other studies show no association [10,11].

Sex-related differences in the distribution of IOP and its changes with age have also been inconsistent across studies. In a study [12] by Mohammed J et al there was a highly significant difference between the mean IOP in males (15.2mmHg) and that in females (16.5mmHg) with the SD of ± 2.43 and ± 3.28 respectively. There was no significant difference in age between the male and female group in this study. Similar association was found in the Barbados Eye study [13], the Rotterdam study [14], the Los Angeles Latino Eye Study [15], and the Beaver Dam Eye Study [16], where men had lower IOP. On the contrary higher IOP was reported for men in the Egna-Neumarkt [17] and the Gutenberg Health [18] studies while the Framingham Eye study [19] and the Health and Nutrition Examination Survey [20] reported no association between sex and IOP.

Methodology

This was a cross sectional study done in a private hospital in Port Harcourt. The first one hundred patients attending the hospital in 2013 and met the inclusion criteria were recruited for the study. Those with corneal disorders were excluded. Informed consent was obtained and the whole exercise followed the tenet of declaration of Helsinki. Age and sex were obtained from the patient’s history while intraocular pressure was measured using Perkins applanation tonometer (MK2 Model). Three readings were taken between 9am and 12pm and the patient’s average value calculated. Patients were in sitting position and had their eye anaesthetized with topical anesthetic agent (1% tetracaine) and then 2% fluorescein dye was instilled before taking the pressures. Intraocular measurements were taken between 9am and 12pm.

Sample size calculation

The minimum sample size was calculated using the formula for quantitative variables. Based on the 95% significance level, an IOP standard deviation of 2.69 from a similar Nigerian study and a precision of 0.55, a minimum sample size of 91 was obtained. However, the study comprised of 100 respondents and a total of 200 eyes were examined.

Statistical analysis

The Statistical Package of Social Sciences (SPSS) version 20 was used for analysis. Descriptive statistics involved means and standard deviation for numerical variables while frequencies and proportions were used for categorical variables. A paired t test was used to compare the differences in mean IOP across left and right eyes. Independent t test was used to compare the differences in mean IOP across two independent categories e.g. gender while Analysis of Variance (ANOVA)/F-test was used for the comparisons across more than two independent categories. Pearson’s correlation coefficient and simple linear regression analysis was used in examining relationship between age and IOP. Statistical significance was set at 0.05.

Table 1: Age and sex distribution of respondents of the study.




  
    Variables (N=100) 
    Frequency 
    Percentage 
  
  
    Age category
     
     
  
  
    <20 years
    12
    12.0
  
  
    20 – 29 years
    6
    6.0
  
  
    30 – 39 years
    18
    18.0
  
  
    40 – 49 years
    22
    22.0
  
  
    50 – 59 years
    15
    15.0
  
  
    =60 years
    27
    27.0
  
  
    Mean age ± S.D = 45.83±20.43years
      Range = 8 – 100 years
     
     
  
  
    Sex
     
     
  
  
    Male
    59
    59.0
  
  
    Female
    41
    41.0
  
  
    S.D: Standard deviation.



Table 1: Age and sex distribution of respondents of the study.

Table 2: Presentation of right and left eye VA of respondents.




  
    VA (N=100) 
    n 
    % 
  
  
    Right eye 
     
     
  
  
    Normal (better than 6/18)
    39
    39.0
  
  
    Mild (6/18)
    16
    16.0
  
  
    Moderate (6/24, 6/36, 6/60)
    32
    32.0
  
  
    Severe (3/60)
    1
    1.0
  
  
    Blindness (worse than 3/60)
    12
    12.0
  
  
     
     
     
  
  
    Left eye 
     
     
  
  
    Normal (better than 6/18)
    36
    36.0
  
  
    Mild (6/18)
    22
    22.0
  
  
    Moderate (6/24, 6/36, 6/60)
    31
    31.0
  
  
    Severe (3/60)
    0
    0.0
  
  
    Blindness (worse than 3/60)
    11
    11.0



Table 2: Presentation of right and left eye VA of respondents.

Table 3: Mean IOP in right and left eye of respondents.




  
     
    Right Eye 
    Left Eye 
     
     
  
  
     
    Mean ± S.D
    Mean ± S.D
    t*
    P-value
  

  
    Intra Ocular Pressure (mmHg)
    16.18±6.13
    16.82±8.22
    0.768
    0.444



Table 3: Mean IOP in right and left eye of respondents.

Result

There were 100 subjects in this study comprising 59 males and 41 females (M:F=3:2). The mean age was 45.83±20.43 years. The mean IOP was 16.18±6.13 for right eye and 16.82±8.22 mmHg for left eye.

Figure 1: Intra ocular pressure of Right eye across age categories.

    
    
    Figure 1:  Intra ocular pressure of Right eye across age categories.

Figure 2: Intraocular pressure in the Left eye across age categories.

    
    
    Figure 2:  Intraocular pressure in the Left eye across age categories.

Figure 3: Intraocular pressure in the Right eye of male and females.

    
    
    Figure 3:  Intraocular pressure in the Right eye of male and females.

Figure 4: Intraocular pressure in the left eye of males and females.

    
    
    Figure 4:  Intraocular pressure in the left eye of males and females.

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Citation: Ejimadu CS, Chinawa NE and Fiebai B. Age and Gender Related Changes in Intraocular Pressure among Patients Attending a Peripheral Eye Clinic in Port Harcourt, Nigeria. Austin J Clin Ophthalmol. 2018; 5(2): 1092.

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	Right Eye	Left Eye
	Mean ± S.D	Mean ± S.D	t*	P-value
Intra Ocular Pressure (mmHg)	16.18±6.13	16.82±8.22	0.768	0.444

Age and Gender Related Changes in Intraocular Pressure among Patients Attending a Peripheral Eye Clinic in Port Harcourt, Nigeria

Abstract

Abbreviations

Introduction

Methodology

Result

Discussion

Conclusion

References

Variables (N=100)	Frequency	Percentage
Age category
<20 years	12	12.0
20 – 29 years	6	6.0
30 – 39 years	18	18.0
40 – 49 years	22	22.0
50 – 59 years	15	15.0
=60 years	27	27.0
*Mean age ± S.D = 45.83±20.43years* *Range = 8 – 100 years*
Sex
Male	59	59.0
Female	41	41.0
S.D: Standard deviation.

VA (N=100)	n	%
Right eye
Normal (better than 6/18)	39	39.0
Mild (6/18)	16	16.0
Moderate (6/24, 6/36, 6/60)	32	32.0
Severe (3/60)	1	1.0
Blindness (worse than 3/60)	12	12.0

Left eye
Normal (better than 6/18)	36	36.0
Mild (6/18)	22	22.0
Moderate (6/24, 6/36, 6/60)	31	31.0
Severe (3/60)	0	0.0
Blindness (worse than 3/60)	11	11.0