Prevalence of Subclinical Keratoconus Among Pediatric Egyptian Population with Astigmatism

Figures & data

Table 1 Classification and Frequency of KC, KC Suspects, and Normal Subjects

Classification	Frequency	Percent	CI*
Normal	497	90.9%	88.49–93.31
KC suspects	24	4.4%	2.68–6.12
KC	26	4.8%	3.01 −6.59

Note: *95% Confidence Interval for the Percentage in the Population.

Figure 1 CSO Sirius scan image of a case of KC.

Figure 2 CSO Sirius scan image of a case of KC suspect.

Figure 3 CSO Sirius scan image of a normal eye.

Table 2 Prevalence of Laterality of Cases

Diagnosis	Frequency	Percent
Normal	497	90.9%
Unilateral KC suspects	15	2.7%
Bilateral KC suspects	9	1.6%
Unilateral KC	13	2.4%
Bilateral KC	13	2.4%

Table 3 Mean Values of Sirius Parameters for Study Groups

Variable	Mean ± Standard Deviation			P
	Normal^a	KC Suspect^b	KC^c
CCT (μm)	544.2 ± 34	534.8 ± 24	520.3 ± 88.7^a	0.004
Pachy thin (μm)	540 ± 34.6	530.4 ± 22.4	500 ± 83.1^a, b	<0.001
K max (D)	46.6 ±2.98^a, b	47.49 ± 3.7^b, c	50.6 ± 4.34^a, c	<0.001
Sim K1 (D)	41.99 ± 1.8^a, b	40.97± 2.45^b,c	43.7 ± 3.99^a, c	0.002
Sim K2 (D)	45.16± 1.85^a,b	44.47± 2.81^b,c	47.73 ± 4.3^a,c	<0.001
Corneal volume (mm3)	58.07 ± 3.71	55.59 ± 3.29^a	57.86 ± 6.41	0.009
ACD (mm)	3.12 ± 0.31	3.52 ± 0.29^a,c	3.23 ± 0.25^b	<0.001
Ant. Elevation (μm)	2.4 ± 6.2^a,b	10.01 ± 1.6^b,c	14.6 ± 10^a,c	<0.001
Post. Elevation (μm)	3.1 ± 5.5^a,b	14.06 ± 2.2^b,c	20.8 ± 13.2^a,c	<0.001
Top. Cylinder (D)	−3.21 ± 1.11	−3.56 ± 0.76	−3.76 ± 1.23^a	0.019

Notes: Letters a, b, and c in any cell mean that there is a significant difference between the mean in this cell and the mean of normal, KC suspect, and KC group.

Abbreviations: CCT, central corneal thickness’ Pachy thin, pachymetry thinnest location; Corneal vol, corneal volume; ACD, anterior chamber depth; Top cyl, topographic cylinder.

Table 4 The Prevalence of KC with Regard to Gender

Gender	Frequency	Percent	CI	P value
Male	18	6.8%	3.77–9.83	0.03*
Female	8	2.8%	0.87–4.73

Note: *Significant at 95% level of significance.

Table 5 The Prevalence of KC with Regard to Age Groups

Age Group	Frequency	Percent	CI	P value
6–12 years	4	1.4%	0.02–2.78	<0.001*
12–18 years	22	8.2%	4.92–11.48

Note: *Significant at 99% level of significance.