Corneal curvature in young high myopic undergraduates in southern Nigeria

Juno Ohiremere Okukpon, Oluwashola Michael Ojo


Background: Corneal curvature is important for contact lens fitting and management, ocular aberration analysis, corneal refractive surgery as well as diagnoses and management of corneal pathological conditions such as keratoconus and it is also an important biometric factor affecting refractive errors, myopia inclusive.

Methods: This was an observational cross-sectional study conducted at the Optometry Teaching Clinic, Department of Optometry, University of Benin, Benin City, Edo State, Nigeria. Two hundred and twenty myopic eyes of 113 (54 males, 59 females) undergraduates students, between 16 and 25 years with myopia of -5.00 to -20.50 participated in this study. Non-cycloplegic refraction was done by retinoscopic measurement and spherical equivalent refraction (SER) of the eyes was calculated. The corneal curvature was determined with a Bausch and Lomb one position Keratometer (Bausch and Lomb Corp., USA).

Results: The mean age, spherical equivalent, corneal curvature and corneal power were 20.44±2.24 years, ̶7.12±3.14DS, 7.72±0.26mm and 43.77±1.48D respectively. Most of the students had a myopia of -5.75 to -10.50DS (46.8%) and a corneal curvature of 7.61-7.90mm (46.82%). There was a difference between the corneal curvature of males and females (P=0.0001). A relationship was also found with gender and corneal curvature (P=0.001).

Conclusions: This study found that high myopic females had shorter corneal curvature, with greater corneal powers than their males counterparts (P<0.01). We also found that gender had a significant relationship with the corneal curvature unlike age and the spherical equivalent which showed no relationship (P>0.01).


Corneal, Corneal curvature, High myopia, Keratometry

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Alasamani A, Mohamed AA. Assessment of biometry and keratometry in low and high degrees of myopia. Albasar Int J Ophthalmol. 2015;3(1):11-4.

Hyman L, Gwiazda J, Hussein M, Norton TT, Wang Y, Marsh-tootle W, et al. Relationship of age, sex, and ethnicity with myopia progression and axial elongation in the correction of myopia evaluation trial. 2005;123.

Saw S, Katz J, Schein OD, Chew S, Chan T. Epidemiology of Myopia. Epidemiol Rev. 1996;18(2):175-87.

Belete GT, Anbesse DH, Tsegaye AT, Hussen MS. Prevalence and associated factors of myopia among high school students in Gondar town, northwest Ethiopia, 2016. Clin Optom. 2017;(9):11-8.

World Health Organization. The impact of myopia impact of increasing and myopia prevalence of myopia. Report of the Joint World Health Organization-Brien Holden Vision Institute Global Scientific Meeting on Myopia. 2015:1-40.

Arora J, Aneja PS, Mehta P, Randhawa BK, Singh KD, Kumar A, et al. Relation of refractive error with corneal curvature of the eye in adult subjects with refractive error. J Evol Med Dent Sci. 2015;4(51):8846-55.

Mashige KP. A review of corneal diameter, curvature and thickness values and influencing factors. S Afr Optom. 2013;72(4):185-94.

Goss DA, Erickson P. Meridional corneal components of myopia progression in young adults and children. Am J Optom Physiol Opt. 1987;64:475-81.

Twelker JD, Mitchell GL, Messer DH, Bhakta R, Jones LA, Mutti DO, et al. Children’s ocular components and age, gender, and ethnicity. Optom Vis Sci. 2009;86:918-35.

Badmus S, Ajaiyeoba A, Adegbehingbe B, Onakpoya O, Adeoye A. Axial length/corneal radius of curvature ratio and refractive status in an adult Nigerian population. Niger J Clin Pract. 2017;(20):1328-34.

Scheiman M, Gwiazda J, Zhang Q, Deng L, Fern K, Manny RE, et al. Longitudinal changes in corneal curvature and its relationship to axial length in the Correction of Myopia Evaluation Trial (COMET) cohort. J Optom. 2016;9(1):13-21.

Iyamu E, Eze NM. The relationship between central corneal thickness and corneal curvature in adult Nigerians. S Afr Optom. 2011;70:44-50.

Iyamu E, Osuobeni E. Age, gender, corneal diameter, corneal curvature and central corneal thickness in Nigerians with normal intra ocular pressure. J Optom. 2012;5:87-97.

Li S, Iribarren R, Kang M, Li H, Li S, Liu L. Corneal power, anterior segment length and lens power in 14-year- old chinese children: the anyang childhood eye study. Sci Rep. 2016:1-8.

Little JA, McClelland JF, Saunders KA, Jackson JA. The relationship between axial length, refractive error and corneal curvature in children and young adults with cerebral palsy. in: association for research in vision and opthalmology, united states of America. Lippincott Williams and Wilkins. 2009;50:1-3.

Mainstone JC, Carney LG, Anderson CR, Clem PM, Stephensen AL, Wilson MD. Corneal shape in hyperopia. Clin Exp Optom. 1998;81(3):131-37.

Grosvenor T, Goss DA. Clinical management of myopia. Optom Vis Sci. 1999;75:132-45.