Introduction: Keratoconus is the most common primary corneal disease. It is a bilateral ectatic 
corneal degeneration characterized by localized corneal thinning which leads to protrusion of the 
thinned cornea. Patients and Methods: Study design: A retrospective comparative study. Ethical 
considerations: The Local Research Ethics Committee, Faculty of Medicine, Minia University 
approved this study. The study adhered to the tenets of the Helsinki Declaration. Results: 
Demographic Data: The mean age of the entire cohort was 29.2±7.7 years (range: 18-54 years). 
Fifty-four patients (35.6 %) were males and 96(64.4%) were females. Fifty patients (33.33%) had 
clinical keratoconus, 50(33.33%) were keratoconus suspects and 50(33.33%) were normal subjects 
were recruited and included in the analysis. The mean age of the clinical keratoconus group was 29.2 
± 7 years (range 19-52 years). Twenty-six patients (52%) were males and 24(48%) were females. The 
mean age of the keratoconus suspect group was 30.7 ± 8.9 years (range 19-52 years). Thirteen patients 
(26%) were males and 37(74%) were females. The mean age of the normal control group was 27.6 ± 
6.9 years (range 18-41 years). Fifteen subjects (30%) were males and 35(70%) were females. There is 
a significant difference in vertical coma, spherical aberrations, RMS HOA and RMS of total 
aberrations between the 3 groups. And there is a significant difference in RMS HOA and RMS of 
total aberrations between the KCS and normal group.