Corneal disease in China

Risk factors for visual impairment associated with corneal diseases in southern China

Purpose

To identify the most common etiologies of corneal disease and the risk factors associated with worse visual outcomes in Changsha, Hunan, located in southern China.

Methods

This observational, cross-sectional study evaluated 100 consecutive patients seen at the cornea clinic of The Second Xiangya Hospital of Central South University. Ocular history, demographic information, and ocular use of traditional Chinese medicine were recorded and analyzed. Causes of infectious keratitis were diagnosed clinically. Fungal and acanthamoeba keratitis were confirmed by confocal microscopy. Visual impairment was categorized based on visual acuity according to World Health Organization recommendations. A binary logistic regression model was used to calculate odds ratio (OR).

Results

One hundred consecutive patients were evaluated. Sixty patients (60%) had noninfectious corneal diseases, most commonly dry eye syndrome (26.7%, n=16), followed by corneal abrasion (18.3%, n=11). Forty-five patients had infectious keratitis, five of whom had both infectious and noninfectious etiologies. Of the patients with infectious keratitis, viral keratitis was the most frequent cause (57.8%, n=26), followed by fungal (20%, n=9) and bacterial (20%, n=9). Older age (OR =5.08, P=0.048), male sex (OR =3.37, P=0.035), and rural residence (OR =3.11, P=0.017) had increased odds of having worse visual impairment. Rural residence was also associated with infectious keratitis (P=0.005), particularly bacterial and fungal keratitis (P=0.046), and a history of ocular trauma (P=0.003). Occupation was not a significant risk factor in this population. Fourteen patients reported use of traditional Chinese medicine, with no association with visual outcomes found.

Conclusion

Older age, male sex, and rural residence were associated with worse visual impairment. Prevalence and outcome of corneal diseases may be improved with an increased awareness in these populations.

γδ T cells regulate the expression of cytokines but not the manifestation of fungal keratitis

As an important immunoregulatory cell type, the role of γδ T cells in fungal keratitis (FK) is unclear. We observed the distribution of γδ T cells in infected corneas in vivo by two-photon microscopy. The γδ T cells were depleted by neutralizing antibodies. The cytokine expression profile was obtained by protein arrays to determine the cytokines regulated by γδ T cells. ICAM-1, MIP-2 and IL-17A were evaluated by ELISA assays to confirm the role of γδ T cells in FK. We counted the number of neutrophils, evaluated the volume of fungal hyphae and analyzed the manifestation of the disease. The γδ T cells increased significantly at 36 h and 72 h post fungal infection (P < 0.05) and migrated from the limbus to the infection site. The neutralizing antibodies completely depleted the γδ T cells in 24 h. The depletion of γδ T cells led to up regulation of 25 cytokines and down regulation of 3 cytokines. ICAM-1, MIP-2 and IL-17A changed significantly because of the depletion of γδ T cells (P < 0.05). However, the number of neutrophils, volume of fungal hyphae and manifestation of the disease was not affected by the depletion of γδ T cells. Our results demonstrated that γδ T cells have a role in FK via regulation of some cytokines but did not affect the manifestation of this disease, suggesting that γδ T cells are not the key regulator cells in this disease.

Prevalence and associated factors of corneal blindness in Ningxia in northwest China

AIM

To describe the prevalence and demographic characteristics of corneal blindness in an urban and rural region of Ningxia, located in the northwest part of China.

METHODS

A stratified, randomized sampling procedure was employed in the study, including urban and rural area of all age group. Visual acuity, anterior segment and ocular fundus were checked. Related factor of corneal disease, including age, gender, education status, ethnic group, location and occupation, were identified according to uniform customized protocol. An eye was defined to be corneal blindness if the visual acuity was <20/400 due to a corneal disease.

RESULTS

Three thousand individuals (1290 from urban area and 1710 from rural area) participated in the investigation, with a response rate of 80.380%. The prevalence of corneal blindness was 0.023% in both eyes and 0.733% in at least one eye. The blindness in at least one eye with varied causes was present in 106 participants (3.533%) and in bilateral eyes in 34 participants (1.133%). The corneal diseases accounted for 20.754% of blindness in at least one eye and 20.588% of bilateral blindness. The prevalence of corneal disease was higher in older and Han ethnic group, especially those who occupied in agriculture and outdoor work. People with corneal blindness were more likely to be older and lower education. Rural population were more likely to suffer from bilateral corneal blindness than the urban population in ≥59-year group (χ (2)=6.716, P=0.019). Infectious, trauma and immune corneal disease were the three leading causes of corneal disease. Trauma corneal disease was more likely leading to blindness in one eye. However, infectious and immune corneal diseases make more contribution to the bilateral corneal blindness.

CONCLUSION

Corneal blindness is a significant burden of in Ningxia population, encompassing a variety of corneal infections and trauma; the majority of those were avoidable. Health promotion strategies and good hygienic conditions have to be developed.