Table of Contents  
ORIGINAL ARTICLE
Year : 2019  |  Volume : 15  |  Issue : 2  |  Page : 39-43

Eyelash status and eye width among ethnic groups in Nigeria


Department of Anatomy, College of Medicine, University of Ibadan, Ibadan, Nigeria

Date of Submission05-Jun-2019
Date of Acceptance08-Feb-2020
Date of Web Publication17-Jul-2020

Correspondence Address:
Adejoke Joan Adekanmbi
Department of Anatomy, College of Medicine, University of Ibadan, Ibadan
Nigeria
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/njps.njps_4_19

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  Abstract 

Objective: As the country becomes increasingly ethnically and racially diverse, it is important for surgeons with an interest in eyelid anatomy to have an appreciation and understanding of eyelash and eye width variations that exist in order to plan for and execute ethnically congruent procedures. The eyelash and eye width analysis is an important aspect of patient assessment for plastic surgeons to identify variations from the normal anatomy. The aim of this study is to inform on anatomical variations that exist between selected ethnic groups as a guide for describing the status of the eyelash and eye width. Enlightenment on these variations will help instruct on important cultural aesthetics, which can be used to plan for blepharoplasty [A1] in a diverse patient population. Materials and Methods: Morphometry of eyelashes and eye width was conducted on 389 healthy volunteers comprising of 193 males and 196 females with no eyelash abnormalities and no eyelash extension participated in the study. The Yoruba tribe consisted of 274, the Igbo tribe were 78 and the Hausa tribe were 37 volunteers respectively. Result: The result showed that the Hausa tribe had the longest lashes with mean values in millimeters of 7.80±1.03, 9.35±1.13 and 8.29±1.19 followed by the Yoruba tribe with mean values of 7.40±3.14, 8.58±1.16 and 7.67±1.12 and then the Igbo tribe with mean values of 7.24±0.93, 8.65±0.89 and 7.72±0.83 on the medial, middle and lateral regions respectively. Further analysis also revealed that males had longer upper eyelid eyelashes in the three regions compared to females. With respect to age, volunteers between the ages of 0–19 years had longer eyelashes than those that were between the ages 20–39 years. The ratio of their mean eye width compared to the mean upper eyelash length was at least 5:1 or more across the three tribes. Conclusion: Morphometric analysis of the eyelashes and eye width provides baseline anatomic data relevant in the performance of cultural background sensitive procedures.

Keywords: Hausa, Ibo, eyelash, eye width, variations, Yoruba


How to cite this article:
Adekanmbi AJ. Eyelash status and eye width among ethnic groups in Nigeria. Nigerian J Plast Surg 2019;15:39-43

How to cite this URL:
Adekanmbi AJ. Eyelash status and eye width among ethnic groups in Nigeria. Nigerian J Plast Surg [serial online] 2019 [cited 2020 Aug 5];15:39-43. Available from: http://www.njps.org/text.asp?2019/15/2/39/290019


  Introduction Top


The morphometric assessment of eyelashes is relevant in increasing knowledge on the general status of eyelash length among the largest and ethnically diverse population of black people and clinically relevant in the diagnosis and treatment of eyelash conditions such as hypotrichosis, or bimatoprost, as well as in eyelash reconstructive surgeries. When eyelash length is extremely long on gross examination, it is obvious on physical inspection of the subject, but with minor increments, it may be difficult to detect or project, hence having an ethnically valid database for comparison among tribes is important in making accurate diagnosis of a probable eyelash abnormality.

According to Kikuchi et al.[1] eyelashes are important structures on the face because of their influence in defining an individual’s overall appearance. They are found on both upper and lower eyelids, and their lengths vary widely by ethnicity. Although the similarities and differences in characteristics of human hair in general has been described based on their ethnic origin: Asian, Caucasian and Africans.[2],[3],[4],[5],[6] Information about eyelash length variations is scarce in comparison to studies on scalp hair.[7] The little information available on ethnic variations in eyelash length is from Asians and Caucasians.[2],[7] There is a dearth in documented data on this subject, among Africans. This is rather unfortunate because of the importance of the eyelashes in protecting the eyeball from small foreign bodies, irritants by stimulating the eye closing reflex.[8] The eyelashes equally serve a periocular landmark role as well as cosmetic function, and thus contribute greatly to the self esteem of the individual bearing the eyelashes.[9],[10] They also play an important role in facial expression, personal interaction as well as divert away airflow from the eyes.[11],[12] This study is targeting bridging this gap in knowledge for clinicians who treat patients from the study target population.


  Materials and methods Top


Subjects

Three hundred and eighty-nine volunteers were admitted for the study, 274 were from the Yoruba tribe, 78 were from the Igbo tribe and 37 were from the Hausa tribe. Subjects were free of any medical problems and had no eyelash-related history such as facial trauma, plastic surgery or ophthalmological surgery. The eye makeup habits of all subjects were checked. All volunteers were instructed to refrain from using mascara, eyeliner or any other makeup products on the periorbital area. The study was in accordance with the Helsinki Declaration of 1975, as revised in 2000 (available at http://www.wma.net/e/policy/17-c_e.html). Confidentiality of subjects was ensured by refraining from mentioning participants’ names, initials or hospital numbers, especially in illustrative material. All volunteers gave informed consent.

Measurements

The subjects were asked to sit in a relaxed manner with their eyes closed. The upper eyelid with their attached eyelashes were divided into three segments along the edge of the eyelid with the medial and lateral cantus serving as the anatomical landmark and markings were made for each segment. From medial to middle and lateral portions were designated as medial, middle and lateral eyelashes respectively. One eyelash each was cut evenly from each segment using a micro-scissors leaving approximately one millimeter of hair on the skin surface from the medial, middle and lateral segments of each eye. The cut eyelashes were placed on a flat surface, straightened and both ends of the eyelashes were held with the adhesive tape to the surface and then measured with the digital caliper. To measure the eye widths, a measuring tape was used. The volunteers were asked to close their eyes and then their eye width which is equivalent to distance from the medial to the lateral canthus of the eye, were measured.

Statistical analysis

Student’s-t test at 5% probability level was used for testing age and gender effects on the eyelash parameters while data on tribe effect were analysed with analysis of variance procedure:

Y ίj = µ + Tί + eίj

µ + Tί + eίj

Yίj= individual observation;

µ= fixed overall mean;

Tί= effect of tribe (Yoruba, Igbo and Hausa);

eίj = experimental error, assumed to be independently and identically normally distributed, with zero mean and constant variance, i.e. ί ίnd (0, r2).

Significant differences between tribes were separated with Duncan Multiple Range Test at 5% probability level.

Furthermore, relationship existing among the investigated eyelash parameters was accessed through correlation coefficients. The ratio of the eye width to the eyelash length was determined by dividing eye width with the average of the eye lash lengths (media, middle and lateral). All data were analysed with Statistical Package for Social Sciences (SPSS) version 16.


  Results Top


Eyelash length

Mean eyelash lengths, width and ratio of three Nigerian tribes which are presented in [Table 1] were measured from medial, middle and lateral segment of eyelids respectively; the Hausa tribe had the longest eyelashes in the three segments but the difference was not significant with mean ± SD presented as follows: Yoruba (medial) 7.40± 3.14, (middle) 8.58± 1.16, (lateral) 7.67± 1.12; Igbo (medial) 7.24±0.93, (middle) 8.65± 0.89, (lateral) 7.72± 0.83; Hausa (medial)7.80±1.03, (middle) 9.35± 1.13, (lateral) 8.29± 1.19.
Table 1 The eyelash lengths among Yoruba, Igbo and Hausa

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Classification based on sex

Mean eyelash lengths were compared in male to females from medial, middle and lateral segment of eyelids respectively as shown in [Figure 1], [Table 2]; the males had the longest eyelashes in the three segments compared to females but the difference was not significant with b[mean ± SD] presented as follows: Males (medial) 7.44± 0.96, (middle) 8.78± 1.04, (lateral) 7.86± 0.98, and Females (medial) 7.37±3.67, (middle) 8.56± 1.19, (lateral) 7.62± 1.17.
Figure 1 A volunteer ’s face showing the different sections of the eyelash that were measured.

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Table 2 The eyelash lengths of male and female

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Classification of eyelash length based on age

Out of the 389 subjects involved in the study, 137 subjects were between the ages 0–19 years and 252 subjects were between the ages 20–39. Mean eyelash lengths were compared in volunteers 0–19 years with ages 20–39 years from medial, middle and lateral segment of eyelids respectively as shown in [Figure 1], [Table 3],[Table 4],[Table 5],[Table 6],[Table 7],[Table 8]. The young volunteers in the age range of (0–19 years old) had the longest eyelashes in the three segments compared to the adult volunteers within the age range of (20–39) years but the differences were was not significant (P > 0.05) with [mean ± SD]a presented as follows: ages 0–19 years (medial) 7.34± 0.95, (middle) 8.84± 1.07, (lateral) 7.78± 0.99, and ages 29–39 years (medial) 7.44±3.27, (middle) 8.58± 1.15, (lateral) 7.72± 1.14
Table 3 The mean ± SD of ages 0–19 years and 20–39 years

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Table 4 The eye width of the tribes

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Table 5 The eye width of male and female

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Table 6 The eye width of ages 0–19 years and 20–39 years

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Table 7 Correlation matrix

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Table 8 The ratio of the eye width to the eyelash length

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Out of the 389 subjects that participated in the study, 274 were from the Yoruba tribe, 78 were from the Igbo tribe and 37 were from the Hausa tribe. Mean eye width in Yoruba was 43.27±2.88ᵇ; in Igbo tribe was 42.24±2.77ᵇ and in Hausa tribe was 42.68±2.55ᵇ. The eye width in the Yoruba was significantly (P < 0.05) different compared to eye width in the Igbo tribe, but there was no significant (P > 0.05) difference between the eye width of the Hausa tribe compared with the Yoruba and the Igbo tribe(s). The eye width in the Yoruba tribe was the widest, followed by the Hausa tribe and the Igbos had the narrowest eye width.

Out of the 389 subjects involved in the study, 193 were males and 196 were females. Mean eye width in males were 43.60±2.59ᵇ; in females was 42.43±2.98a. The eye width in males was significantly different compared to eye width in females. The eye width in the males was the widest compared to females.

Out of the 389 subjects involved in the study, 137 subjects were between the ages 0-19 years and 252 subjects were between the ages 20–39. Mean eye width in males was 42.77±3.02a; in females was 43.14±2.75a. The eye width between the ages of 0–19 years was not significantly different compared to the age 20–39 years.


  Correlation matrix Top


The total of the medial, middle and lateral lengths of the collected eyelashes were collated and then compared to see if there was any correlations among them. Also, they were also compared with the eye width to find the correlations between them. The results are in the table below:


  Discussion Top


Eyelashes are hairs that grows at the outermost tips of the eyelid where they protect the eye from foreign bodies.[7] In contrast to scalp hair, variations in eyelashes length among different ethnic groups has not been extensively reported. In the present population, the middle eyelash segments are the longest in comparison to the medial and lateral segments of the eyelashes. Lateral eyelashes are the second longest segment while the medial eyelashes segments are the shortest. Among the three tribes, the Hausa tribe has the longest eyelashes for the three segments measured; medially, the Hausa tribe had the longest lashes with a mean value of 7.80 ±1.03 (mm), followed by the Yoruba tribe with a mean value of 7.40±3.14 (mm) and then the Igbo tribe with a mean value of 7.24±0.93 (mm). On the middle side of the eye, the Hausa tribe also had the longest lashes with a mean value of 9.35±1.13 (mm), followed by the Igbo tribe with a mean value of 8.65mm ±0.89 (mm) and then the Yoruba tribe with a mean value of 8.58mm ±1.16(mm). Laterally, the Hausa tribe had the longest lashes also, with a mean value of 8.29±1.19(mm), followed by the Igbo tribe with a mean value of 7.72±0.83(mm) and then the Yoruba tribe with a mean value of 7.67±1.12(mm). Documented length of eyelashes among the Japanese ranged between 8 and 12 (mm) in the upper eyelash across all eyelash region.[7],[13] This implies that all three populations studied here have medial eyelashes that are slightly lesser than what was morphometrically determined among the Japanese. While, the middle eyelashes appear to fall into the range found among the Japanese, the lateral eyelashes among the Hausas fell into this range but the Ibos and Yourubas were shorter. It is possible that the slight reduction in length is as a result of the fact that African hair has less tensile strength thus reaching breaking point before those of other racial groups (Khumalo et al., 2006). This means that African hair is more fragile than that of other races hence a tendency to break before reaching comparable length with other ethnicities like the Japanese.[2]

Medially, the mean value of the males was 7.44±0.96 (mm) while that of the females was 7.37±3.67 (mm). On the middle segment of the eye, the males had lashes with a mean value of 8.78±1.04 (mm) while the females had shorter lashes with a mean value of 8.56 ±1.19 (mm). Laterally, the males had longer eyelashes also, with a mean value of 7.86±0.98 (mm) while the females had shorter lashes with a mean value of 7.62±1.17 (mm). A study conducted on Japanese individuals compared the longest region of the eyelashes of females to the males using measurement from scaled images from a digital camera and result showed that mean eyelash lengths in males and females were 7.33 ± 0.83 (mm) and 7.47 ± 0.68 (mm), respectively.[1]

Adults (20–39 years old) had longer lashes on the medial side with a mean value of 7.44±3.27(mm) while children including teenagers (0–19 years) had shorter lashes with a mean value of 7.34m±0.95 (mm). On the middle side, children had longer eyelashes with a mean value of 8.84±1.07 (mm) while the adults had shorter lashes with a mean value of 8.58±1.15 (mm). Laterally, the children had longer eyelashes with a mean value of 7.78±0.99 (mm) and the adults had shorter lashes with a mean value of 7.72±1.14 (mm). In general, children have longer eyelashes compared to adults. Glaser et al.[14] conducted on a population of healthy American women, in which it was found that advancing age among an ethnically diverse population is associated with significant decreases in eyelash length, thickness, and darkness.Analysis of differences in length among the ethnic tribes revealed that the Yoruba tribe had the widest eye width with a mean value of 43.27±2.88 (mm), followed by the Hausa tribe with a mean value of 42.68 ± 2.55(mm) and followed by the Igbo tribe with a mean value of 42.24±2.77 (mm).

Males had wider eyes with a mean value of 43.60±2.59 (mm) compared to the females who had a mean value of 42.43±2.98 (mm). Studies have reported the mean values for eye width among Kenyans females to be 33.7 (mm), North American whites; 30.7 (mm) and African Americans to be 32.2 (mm). The Kenyan males had eye width 34.0 (mm), North American whites 31.3 (mm) and African American 32.9 (mm). Adults had wider eyes with a mean value of 43±2.75 (mm) compared to the children with a mean value of 42.77±3.02 (mm).

With respect to the ratio of eye width to eyelash length, the approximate ratio was 5 to 1, this contrasts with results of Amador et al.[12] who reported a ratio of 3:1 across different mammalian species including humans.

Significant high correlation coefficient between lateral and medial is suggestive that strong relationship exists between the two variables. This result implies that the lateral and medial are possibly under the control of similar gene(s) with pleiotropic effect. Factors that could account for ethnic difference in length of eyelash could be environment, diet, hormones, drugs and pharmacologic agents among other things.


  Conclusion Top


The findings suggest that advancing age in an ethnically diverse population of healthy women is correlated with significant decreases in eyelash length, thickness, and darkness.

The findings in this study suggest that there are variations in the length of eyelashes and eye width across three regions of the upper eyelid among people of African ancestry particularly among three Nigerian tribes (Yoruba, Igbo and Hausa). This study informs on anatomical variations that exist in the dimensions of the eye width and eyelashes of the selected ethnic groups as a guide for incorporating important cultural aesthetics among Nigerians which can be used to plan for eyelash surgical transplantation and management procedures.

Acknowledgment

The contributions of Ms Napoleon is appreciated.

Financial support and sponsorship

Nil.

Conflict of Interests

The author declares that there is no conflict of interests regarding the publication of this paper



 
  References Top

1.
Kikuchi M, Matsuda K, Ishihara Y, Yanai T, Yasuta K, Hosokawa K, Uemura TA. Study of normal eyelashes in Japanese individuals. 2015;2(1):74-77.  Back to cited text no. 1
    
2.
Franbourg A, Hallegot P, Baltenneck F et al. Current research on ethnic hair. J Am Acad Dermatol 2003;48:S115-19.  Back to cited text no. 2
    
3.
Wolfram LJ. The reactivity of human hair. In: (Orfanos CE, Montagna W, Stuttgen G, eds) Hair Research, Status and Future Aspects, Berlin, Heidelberg: Springer-Verlag, 1981;479-500  Back to cited text no. 3
    
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Menkart J, Wolfram LJ, Mao I. Caucasian hair, Negro hair and wool: similarities and dif-ferences. J Soc Cosmet Chem 1984;35:21-43.  Back to cited text no. 4
    
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Dekio S, Jidoi J. Hair low-sulphur protein composition does not differ electrophoretically among different races. J Dermatol 1988;15:393-6.  Back to cited text no. 5
    
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Wolfram LJ. Human hair: a unique physicochemical composite. J Am Acad Dermatol 2003;48:S106-14.  Back to cited text no. 6
    
7.
Na JI, Kwon OS, Kim BJ, Park WS, Oh JK, Kim KH, Cho KH, Eun HC. Ethnic characteristics of eyelashes: a comparative analysis in Asian and Caucasian females. Brit-ish Journal of Dermatology 2006;155: pp 1170-1176  Back to cited text no. 7
    
8.
Umar S. Eyelash transplantation using leg hair by follicular unit extraction. Plast Reconstr Surg Glob Open 2015;3:e324; doi: 10.1097/GOX. 0000000000000292; Published online 16 March 2015.  Back to cited text no. 8
    
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Robins CR. Chemical and Physical Behavior of Human Hair. 4th ed. New York, NY: Springer-Verlag 2002.  Back to cited text no. 9
    
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Vij A, Bergfeld WF. Clin Dermatol 2015;33:217-26. Doi: 1016.  Back to cited text no. 10
    
11.
Cohen JL. Enhancing the growth of natural eyelashes: the mechanism of bimatoprost-induced eyelash growth. Dermatol Surg 2010;36:1361-71.  Back to cited text no. 11
    
12.
Amador GJ, Mao W, DeMercurio P, Montero C, Clewis J, Alexeev A, Hu DL. Eyelashes divert airflow to protect the eye. J R Soc Interface 2015;12:20141294. http://dx.doi.org/10.1098/rsif.2014.1294.  Back to cited text no. 12
    
13.
Liotet S, Riera M, Nguyen H. The lashes, physiology, structure, pathology. Arch Ophtalmol (Paris) 1977;37:697-708.  Back to cited text no. 13
    
14.
Glaser DA, Hossain P, Perkins W et al. Long-term safety and efficacy of bimatoprost solution 0.03% application to the eyelid margin for the treatment of idiopathic and chemotherapy-induced eyelash hypotrichosis: a randomized controlled trial. British Journal of Dermatology 2015;172:1384-94.  Back to cited text no. 14
    


    Figures

  [Figure 1]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8]



 

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Abstract
Introduction
Materials and me...
Results
Correlation matrix
Discussion
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