A hospital-based study on clinical data, demographic data and visual function of keratoconus patients in Central China

Abstract

China is a populous country but lacks epidemiological data on keratoconus (KC). The present study aimed to investigate the clinical data, demographic data, and visual function (VF) data of KC patients in Central China. A total of 524 KC eyes in 307 KC patients (217 bilateral and 90 unilateral) from Henan Eye Hospital were included in the current study. Demographic and VF data were assessed with questionnaires administered by well-trained staff during face-to-face interviews. Visual acuity value was examined by a qualified optometrist, and the clinical data were measured by professional clinicians. The distributions of sex, residence and education level of KC patients were compared by Chi-square tests, and the ratios of people wearing glasses and rigid gas permeable (RGP) lenses were compared by McNemar tests. General linear models/Chi-squared tests were used to compare the clinical and demographic data according to KC severity. Spearman’s correlation analysis was used to test the associations between the data and KC severity. The mean age at diagnosis was 20.98 ± 6.06 years, and males had a higher ratio of KC than females (P < 0.001). Patients in rural areas had a higher rate of KC than those in urban areas (P = 0.039), and the proportion of KC patients with a higher education level (above high school) was high (P < 0.001). A total of 68.40% of the patients reported eye rubbing and 3.52% had a positive family history. The percentage of people wearing glasses was higher than that of patients wearing RGP lenses (P < 0.001). The total VF score of KC patients was 69.35 ± 15.25. The thinnest corneal thickness (TCT) and stiffness parameter at the first applanation (SP-A1) values were inversely correlated with KC severity (P < 0.05). The mean, steep, and max keratometry (Km, Ks and Kmax) values, the RGP lens use and keratoplasty were positively correlated with KC severity (all P < 0.05). The total VF score of the eye with better VA decreased as the severity increased (r = − 0.21, P = 0.002). The present study comprehensively describes various associated features of KC patients from a tertiary hospital in Central China, providing a reference for understanding the characteristics of KC patients in China.

Distribution of pediatric keratoconus by different age and gender groups

“…A gender-related difference is believed to play an important role in changes in corneal tissue structures (27-30). Male patients account for a higher proportion than female patients based on previous investigations of adult keratoconus (7,9,10,31,32). A high male/female ratio still exists for pediatric keratoconus.…”

Baseline Characteristics of 1976 Patients With Ectatic Corneal Disorders at a Single Center From 2010 to 2021: A Cross-Sectional Study of the Homburg Keratoconus Center

“…Regarding KC characteristics compared with other monocentric studies and with the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) studies, the present analysis included the largest number of cases 4,5,9,10,13,[15][16][17][18][19][20][21][22] and with 818 eyes is one of the largest studies reporting corneal biomechanical characteristics from the Corvis ST system. 12,[23][24][25] Keratoconus is generally detected during puberty or early adolescence and progresses maximally until the fourth decade of ANGLE, angle of anterior chamber; ARTMAX, Ambro ´sio relational thickness maximum; Asph, aspherical degree of corneal shape; BADA, deviation from the mean of Ambro ´sio relational thickness; BADB, deviation of back elevation difference map; BADD, Belin/Ambro ´sio enhanced ectasia total deviation value; BADF, deviation of front elevation difference map; BADISTAPEX, distance from apex to the thinnest point; BADP, deviation of average pachymetric PTIression; BADT, deviation of minimum thickness; BADY, deviation from the vertical displacement of the thinnest point from the apex; CCT, pachymetry at the center; CHAMBVOL, anterior chamber volume; CKI, central KC index; CORVOL, corneal volume; CTSP0, corneal thickness at the thinnest point; CTSP10, mean corneal thickness at the 10 mm meridian; CTSP2, mean corneal thickness at the 2 mm meridian; CTSP4, mean corneal thickness at the 4 mm meridian; CTSP6, mean corneal thickness at the 6 mm meridian; CTSP8, mean corneal thickness at the 8 mm meridian; HKC, Homburg Keratoconus Center; IHA, index of height asymmetry; IHD, index of height decentration; IOP, intraocular pressure correction factor; ISV, index of surface variance; IVA, index of vertical asymmetry; K1, flat central keratometry (3 mm); K2, steep central keratometry (3 mm); KI, KC index; Km, mean central keratometry (3 mm); Kmax, maximum keratometry (overall); Kmax_x, location of Kmax at the horizontal axis; Kmax_y, location of the Kmax at the vertical axis; Axis, Axis of the flat meridian; KPD, keratometric power deviation; PTI0, percentage of thickness increase at the thinnest point; PTI10, percentage of thickness increase at the 10 m meridian; PTI2, percentage of thickness increase at the 2 mm meridian; PTI4, percentage of thickness increase at the 4 mm meridian; PTI6, Percentage of thickness increase at the 6 mm meridian; PTI8, percentage of thickness increase at the 8 mm meridian; PTIMAX, maximum progression of corneal thickness; PTIMAX_Axis, axis of maximum progression of corneal thickness; PTIMIN, minimum progression of corneal thickness; PTIMIN_Axis, axis of minimum progression of corneal thickness; Rh, Radius of the horizontal meridian; Rm, mean Radius; Rmin, minimum radius; Rper, mean radius of curvature in the seven-to 9-mm area; Rv, Radius of the vertical meridian; TCT, thinnest pachymetry; TCT_x, location ...…”

“…8 Compared with normal corneas, corneas of KC patients have lower volume, are thinner, and show a faster and more abrupt increase in corneal thickness spatial profile and percentage thickness increase. 9,10 Combined tomographic parameters, such as the Belin/Ambrósio enhanced ectasia total deviation value or the Ambrósio relational thickness maximum, are excellent tools that provide an enhanced approach for detecting KC. 11 Although several systems are available for KC staging based on various parameters, the ABCDE classification system is well established and improves diagnosis and assessment of progression in KC.…”

“…9 In addition, most hospital-based studies have provided information about KC characteristics but have been limited no more than 500 participants. 9,10,[15][16][17][18][19] Even the most recent multicentric collaborative studies enrolled no more than 1,500 patients. 13,16,19,20 Despite technological advances and the large number of studies analyzing the characteristics and factors associated with KC, detection remains challenging in the early stages.…”

A Hospital-Based Study on the Prevalence of Keratoconus in First-Degree Relatives of Patients with Keratoconus in Central China

“…A positive family history of KC is a strong indication of a genetic predisposition [ 25 ]. In the current study, the prevalence of KC in 661 first-degree relatives of 384 KC patients was 8.77%.…”