Refractive and Corneal Topographic Characteristics in Upper Egypt Children With High Cylinder

Astigmatism is defined as, a refractive condition in which refractive light fails to form a focus on the retina, it accounts for about 13% of refractive errors. It is frequent and correctable cause of visual impairment in children whether associated with spherical errors or not.

Astigmatism, is the refractive error of the highest clinical importance, being associated with reduced visual acuity with subsequent development of refractive amblyopia.

High cylinder in children belong to areas of hot and dry climates, makes exclusion of keratoconus is mandatory. Population in the African continent, the Mediterranean countries, Central and South America, and the Indian subcontinent usually have the habit of eye rubbing because of bothering symptoms of dryness, itching, atopy, allergy and vernal keratoconjunctivitis, which is the severe form of allergic conjunctivitis.

Eye rubbing causes thinning of keratocyte and increases the prevalence of keratoconus.

Keratoconus in children (diagnosed before the age of eighteenth) is less common but more aggressive than that of the adults, due to the dynamic nature of the young cornea. Few studies in the literature reported the prevalence and incidence of keratoconus in children.

Pentacam is an advanced instrument with a rotating Scheimpflug camera for scanning the anterior and posterior corneal surfaces. Its measurements of the corneal thickness and posterior elevation have been proved to be of high reproducibility and repeatability.

• Pentacam and autorefractometry (Other): Pentacam to detect corneal topographic changes. Auto-refractometry to assess refraction condition of the children

Primary outcomes

• Values anterior and posterior corneal elevation values by pentacam. [one year]: Corneal topgraphic changes in children with high cylinder in upper Egypt

Sex: All, ages: 7 Years to 18 Years

Inclusion Criteria:

\- Upper Egypt children with high cylinder(refractive errorr).

Exclusion Criteria:

* Children below age of 7 years old (uncooperative), patients above age of 18 years old.Patients with corneal scars

• Elshimaa A.Mateen, Principal investigator, Assistant professor of ophthalmology, Sohag University