Abstract
Objective: To determine the prevalence of keratoconus among patients with allergic conjunctivitis aged
between 8 and 30 years, attending Kenyatta National Hospital eye clinic.
Methods: A cross sectional study of patients on follow up for allergic conjunctivitis. They were examined on the
slit lamp, clinical signs of keratoconus were elicited, and then keratometry and corneal topography was done on
each of them. The social demographic and clinical data was captured in a questionnaire. Descriptive analysis of
the data was done to determine means, frequencies and proportions of the various variables. The relationship
between the demographic characteristics of the patients, the duration and severity of allergic conjunctivitis,
with keratoconus was assessed.
Results: Two hundred and forty six eyes of 123 patients were examined. Keratoconus prevalence was found to
be 10.6% by clinical diagnosis, 14.6% by keratometry and 30.9% by topography. Majority of those diagnosed
with keratoconus were aged 10 to 14 years (42.1%). The male: female ratio of those with keratoconus was 1.9:1,
and among them 34.2% had moderate allergic conjunctivitis, and 42.1% had severe allergic conjunctivitis, which
was statistically significant. Patients with allergy symptoms for more than 10 years formed the largest proportion
of those with keratoconus (42.1%).
Conclusion: The prevalence of keratoconus in patients with allergic conjunctivitis was found to be high and
the majority were male. Corneal topography diagnosed more patients with keratoconus, and therefore is highly
recommended as part of the follow up investigations for all patients with allergic conjunctivitis. This will ensure
early detection and management of the condition.
References
Gordon-Shaag A, Millodot M, Shnear E. The
epidemiogy and etiology of keratoconus. Int J
Keratoconus Ectatic Dis. 2012; 1(1):7–15.
What Causes Keratoconus| KC theories | Genetic/
Environmental [Internet]. NKCF. [cited 2015 Mar
. Available from: http://www.nkcf.org/what-iskeratoconus/
Nielsen K, Hjortdal J, Aagaard Nohr E, Ehlers N.
Incidence and prevalence of keratoconus in Denmark.
Acta Ophthalmol Scand. 2007: 85(8):890–892.
Cozma I, Atherley C, James NJ. Influence of ethnic
origin on the incidence of keratoconus and associated
atopic disease in Asian and white patients. Eye.
;19(8):924–925.
Nowak DM, Gajecka M. Genetics of keratoconus.
Middle East Afr J Ophthalmol [Internet]. 2011:18(1).
Available from: http://www.meajo.org
Bawazeer A, Hodge W, Lorimer B. Atopy and
keratoconus: a multivariate analysis. Br J Ophthalmol.
; 84(8):834 - 836.
Lapid-Gortzak R, Rosen S, Weitzman S, Lifshitz T.
Videokeratography findings in children with vernal
keratoconjunctivitis versus those of healthy children.
Ophthalmology. 2002;109(11):2018–23.
Totan Y, Hepşen I, Çekiç O, Gündüz A, Aydın E.
Incidence of keratoconus in subjects with vernal
keratoconjunctivitis. Ophthalmology. 2001;
(4):824–827.
Shoja M, Besharati M. Evaluation of keratoconus
by videokeratography in subjects with vernal
keratoconjunctivitis (VKC). J Res Med Sci.
;11(3):164–169.
Wade P, Iwuora A, Lopez L, Muhammad M. Allergic
conjunctivitis at Sheikh Zayed Regional Eye Care Center,
Gambia. J Ophthalmic Vis Res. 2012;7(1):24–28.
De Smedt S, Nkurikiye J, Fonteyne Y, Tuft S,
Gilbert C, Kestelyn P. Vernal keratoconjunctivitis
in school children in Rwanda. Ophthalmology.
;119(9):1766–72.
Waweru F , Bhaiji M. Vernal keratoconjunctivitis as
seen at Kenyatta National Hospital. MMed Thesis;
University of Nairobi. 1991.
Dantas P, Alves M, Nishiwaki-Dantas M.
Topographic corneal changes in patients with
vernal keratoconjunctivitis. Arq Bras Oftalmol.
;68(5):593–598.
American Academy. External disease and cornea.
American Academy of Ophthalmology;
Bore M, Ilako D. Clinical evaluation criteria of ocular
allergy by ophthalmologists in Kenya and suggested
grading sysytems. J Ophthalmol East Cent South Afr.
;18(1):35–43.
Thengil D. Association between keratoconus and
vernal keratoconjunctivitis/Allergic conjuctivitis in
Zambia. 2014;
John AK, Asimellis G. Revisiting keratoconus
diagnosis and progression classification based on
evaluation of corneal asymmetry indices, derived
from Scheimpflug imaging in keratoconic and suspect
cases. Clin Ophthalmol Auckl NZ. 2013;7:1539–48.
Millodot M, Shneor E, Albou S, Atlani E, Gordon-
Shaag A. Prevalence and associated factors of
keratoconus in Jerusalem: a cross-sectional study.
Ophthalmic Epidemiol. 2011;18(2):91–97.
Ertan A, Muftuoglu O. Keratoconus clinical findings
according to different age and gender groups. Cornea.
;27(10):1109–13.
Batool J, Henia L, Doyle SR. Asymmetric keratoconus
attributed to eye rubbing. Cornea.[Internet].
LWW. [cited 2014 Nov 26]. Available from: http://
journals.lww.com/corneajrnl/Fulltext/2004/08000/
Asymmetric_Keratoconus_Attributed_to_Eye_
Rubbing.6.aspx