The Collagen Factors of Rapid Progression of Keratoconus in Children.

The purpose of this observational study was to understand the differences in clinical features and mechanisms of keratoconus between children and adults. The main questions it aimed to answer as follows: (1) to understand the characteristics of keratoconus in Chinese children. (2) to observe corneal stromal cells at the cytological level using in vivo corneal laser confocal microscopy and explore the pathogenesis.

Keratoconus is a progressive and asymmetric corneal dilation disease, in which the cornea presents as a conical protrusion, leading to irregular astigmatism, progressive myopia, corneal thinning, and subsequent visual impairment. If left untreated, acute corneal edema may occur in the late stage, resulting in a sharp decline in vision. This disease is a binocular disease and can occur unilaterally first. The incidence rate of the general population is 1/2000. Most of the diseases described in the literature began in adolescence, and about 90% of the patients were diagnosed at the age of 10. Some literature reported that the youngest patient was 4 years old, and the disease generally remained stable until about 40 years old.

Currently, research on pediatric keratoconus mainly includes the prevalence and morphological characteristics, as well as the progression of corneal collagen cross-linking surgery. The younger onset age of KC is often associated with rapid progression and late stage disease diagnosis. Scholars have observed that 88% of children develop KC after one year of diagnosis, and advocate for early corneal collagen cross-linking treatment for these children's eyes. However, the reasons for the onset and progression of keratoconus in children at a young age are not yet clear.

Due to the young age of onset and unclear reasons for the progression of pediatric keratoconus in clinical practice, as well as insufficient research on pediatric keratoconus in recent years, the clinical characteristics of pediatric keratoconus are still lacking, and the pathogenesis of pediatric keratoconus is still unclear. Therefore, this study aims to compare pediatric keratoconus with adult keratoconus, extract the characteristics of pediatric keratoconus, and use a live corneal laser confocal microscope to observe the stromal cellular structure inside pediatric keratoconus, in order to provide some clinical reference for the pathological understanding of pediatric keratoconus.

Eligibility Criteria:
Inclusion Criteria:

* ① Patients with keratoconus who visit the refractive clinic.

  1. The height of the posterior corneal surface is greater than 16 microns under the Pentacam corneal topography.
  2. ARTAve \< 424 microns, ARTMax \< 339 microns.
  3. Clinical non-inflammatory or traumatic corneal thinning and corneal astigmatism.

     * Aged between 10 and 50 years old, no gender restrictions.

       * Agree to accept and complete follow-up examinations on time. ④ I and my guardian understand and agree to participate in this clinical trial and sign the informed consent form.

Exclusion Criteria:

* ① There is a history of contact lens wearing in the last four weeks.

  * poor fixation and can not cooperate with the examination. ③ History of eye trauma and surgery (including corneal collagen cross-linking surgery).

    * History of other related eye diseases: corneal disease, glaucoma, retinal choroid disease, etc..

      ⑤ severe eye diseases affecting imaging such as dry eye, conjunctivitis and pterygium.

      ⑥ Any systemic disease affecting eye morphology and refractive interstitium.