DOI: http://dx.doi.org/10.18203/2349-3933.ijam20214128

Relationship between axial length, keratometry and central corneal thickness in patients with refractive errors at a teaching hospital in Southwest, Nigeria

Anthony O. Betiku, Adeola O. Onakoya, Olufisayo T. Aribaba, Omodele O. Jagun

Abstract


Background: Aim of the study was to determine the relationship between axial length (AL), keratometry and central corneal thickness (CCT), and refractive errors in adult patients attending the Guinness eye centre (GEC), Lagos university teaching hospital (LUTH) Idi-Araba, Lagos.

Methods: A descriptive cross-sectional study conducted among consecutive patients aged 16 years and above with refractive errors attending the GEC, LUTH. Ocular parameters measured included AL, anterior corneal curvature, CCT and refractive errors. AL and keratometry were measured with IOL master and CCT with ultrasonic A scan pachymeter. Refraction was done with auto-refractor-keratometer. Data analysis was done with statistical package for social science (SPSS) 20.

Results: A total of 394 patients were studied, 157 males and 237 females. The age range was 16-65 years, mean -37.9±13.3 years and median -36.5 years. There were more myopic patients 215 (54.6%) than hyper-metropes 179 (45.4%). The mean AL was 23.9±1.1 mm and eyes with longer AL were more likely to be myopic (r=-0.676, p<0.001); to have flatter cornea (r=0.519, p<0.001) and thicker cornea (r=0.149, p=0.003). The mean CCT was 520.3±31.0 µm. There was a weak negative correlation between CCT and refractive error (r=-0.111, p=0.027).

Conclusions: The mean CCT was lower than the mean CCT of other Nigerian studies. Hypermetropic patients were more likely to have thinner corneas. This may lead to underestimation of intraocular pressure (IOP) in these patients. Significant correlation was seen between AL and refractive error, CCT and keratometry. AL correlated with less spherical equivalent refractive error, flatter and thicker cornea. It is therefore important to measure the CCT of all patients going for refractive surgery to detect those at risk of developing corneal ectasia following refractive surgery.


Keywords


AL, Keratometry, CCT, Refractive error

Full Text:

PDF

References


Hashemi H, Fotouhi A, Yekta A, Pakzad R, Ostadimoghaddam H, Khabazkhoob M. Global and Regional Estimates of Prevalence of Refractive Errors: Systematic Review and Meta-Analysis. J Curr Ophthalmol. 2018;30:3-22.

Sawada A, Tomidokoro A, Araie M, Iwase A, Yamato T. Refractive Errors in an Elderly Japanese Population: The Tajimi Study. Ophthalmol. 2008;115:363-70.

Gomez-Salazar F, Campos-Romero A, Gomez-Campaña H, Cruz-Zamudio C, Chaidez-Felix M, Leon-Sicairos N et al. Refractive Errors among Children, Adolescents and Adults Attending Eye Clinics in Mexico. Int J Ophthalmol. 2017;5:796-802.

Pascolini D, Mariotti SP. Global estimates of visual impairment: 2010. Br J Ophthalmol. 2012;96(5):614-8.

Holden BA, Sulauman S, Knox K. The challenge of providing spectacles in the developing world. Comm Eye Health J. 2000;13:9-10.

Naidoo KS, Leasher J, Bourne RR. Global vision impairment and blindness due to uncorrected refractive error, 1990-2010. Opto Vis Sci. 2016;93(3):227-34.

Abdull MM, Sivasubramaniam S, Murthy GV, Gilert C, Abubakar T, Ezelum C et al. Causes of blindness and visual impairment in Nigeria: The Nigeria national blindness and visual impairment survey. Investigative Ophthalmol Visual Sci. 2009;50(9):4114-20.

Ezelum C, Razavi H, Sivasubramaniam S, Gilbert CE, Murthy G, Entekume G et al. Nigeria National Blindness and Visual Impairment Study Group. Refractive Error in Nigerian Adults: Prevalence, Type, and Spectacle Coverage. Invest Ophthalmol Vis Sci. 2011;52:5449-56.

Ajayi IA, Omotoye OJ, Omotoso-Olagoke O. Profile of refractive error in Ekiti, South Western Nigeria. Afr Vis Eye Health. 2018;77(1):a415.

Flitcroft DI, Knight E, Nanan D, Bowel R, Lanigan B, O’Keefe M. Intraocular lenses in children: change in axial length, corneal curvature and refraction. Br J Ophthalmol. 1999;83:265-9.

Grosvenor T, Scott R. Role of the axial length/corneal radius ratio in determining the refractive state of the eye. Optom Vis Sci. 1994;71:573-9.

Ip JM, Huynh SC, Kifley A, Rose KA, Morgan IG, Varma R et al. Variation of the contribution from axial length and other oculometric parameters to refraction by age and ethnicity. Invest Ophthalmol Vis Sci. 2007;48:4846-53.

Damji KF, Muni RH, Munger RM. Influence of corneal variables on accuracy of intraocular pressure measurement. J Glaucoma. 2003;12:69-80.

Herndon LW, Choudhri SA, Cox T, Damji KF, Shields B, Allingham RR. Central corneal thickness in normal, glaucomatous, and ocular hypertensive eyes. Arch Ophthalmol. 1997;115:1137-41.

Adefule-Ositelu AO, Refractive errors in Lagos, Nigeria. Nig Med J. 1995;29;101-3.

Adegbehingbe BO, Majekodunmi AA, Akinsola FB, Soetan EO. Pattern of refractive error at Obafemi Awolowo University Teaching Hospital, Ile-Ife, Nigeria. Nig Med J. 2003;11:76-9.

Chen M, Liu Y, Tsai C, Chen Y, Chou C, Lee S. Relationship between central corneal thickness, refractive error, corneal curvature, anterior chamber depth and axial length. J Chin Med Assoc. 2009;72:133-7.

Chang SW, Tsai IL, Hu FR, Lin LL, Shih YF. The cornea in young myopic adults. Br J Ophthalmol. 2001;85:961-70.

Sanchis Gimen JA, Alonso L, Arribas I, Asensio I, Rahhal MS, Martínez Soriano F. Assessment of differences in ocular morphometric measurements by using optical and applanation ultrasound biometry in the same eye. Eur J Anat. 2002;6:127-32.

Adio AO, Onua DO, Arowolo D. Ocular axial length and keratometry reading of normal eyes in Southern Nigeria. Nigerian J Ophthalmol. 2010;18:12-4.

Yin G, Wang YX, Zheng ZY, Yang H, Xu L, Jonas JB. Ocular axial length and its associations in Chinese: The Beijing Eye Study. PLoS ONE. 2012;7(8):e43172.

Cegarra MJ, Izquierdo JC, Alonso I, Gil de Tejada TH, Rahhal MS, Soriano FM et al. Consolidating the anatomical relationship between ocular axial length and spherical equivalent refraction. Eur J Anat. 2001;5:145-50.

Mainstone JC, Carney LG, Anderson CR, Clem PM, Stephensen AL, Wilson MD. Corneal shape in hyperopia. Clin Exp Optom. 1998;81:131-7.

Eysteinsson T, Jonasson F, Sasaki H, Arnarsson A, Sverrisson T, Sasaki K et al. Central corneal thickness, radius of the corneal curvature and intraocular pressure in normal subjects using non-contact techniques: Reykjavik Eye Study. Acta Ophthalmol Scand. 2002;80:11-5.

Al Mahmoud T, Priest D, Munger R, Jackson WB. Correlation between refractive error, corneal power and thickness in a large population with a wide range of ametropia. Invest Ophthalmol Vis Sci. 2011;52:1235-42.

Cho P, Lam C. Factors affecting the central corneal thickness of Hong Kong-Chinese. Curr Eye Res. 1999;18:368-74.

Sheridan M, Douthwaite W. Corneal asphericity and refractive error. Ophthalmic Physiol Opt. 1989;9:235-8.

Nemesure B, Wu SY, Hennis A, Leske MC. Corneal thickness and intraocular pressure in the Barbados Eye Studies. Arch Ophthalmol. 2003;121:240-44.

Aghaian E, Choe JE, Lin S, Stamper RL. Central corneal thickness of Caucasians, Chinese, Hispanics, Filipinos, African Americans, and Japanese in a glaucoma clinic. Ophthalmology. 2004;111:2211-9.

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

Faragher RGA, Mulholland B, Sandeman S, Tuft SJ, Khaw PT. Aging and the cornea. Br J Ophthalmol. 1997;81:814-7.

Mercieca K, Odogu V, Fiebai B, Arowolo O, Chukwuka F. Comparing central corneal thickness in a sub-saharan cohort to African Americans and Afro-Caribbeans. Cornea. 2007;26:557-60.

Oliveira C, Tello C, Liebmann J, Ritch R. Central corneal thickness is not related to anterior scleral thickness or axial length. J Glaucoma. 2006;15:190-4.

Fam HB, How ACS, Baskaran M, Lim KL, Chan YH, Aung T et al Central corneal thickness and its relationship to myopia in Chinese adults Br J Ophthalmol. 2006;90:1451-3.