What is the non-inflammatory eye condition in which the cornea steepens and thins?

Keratoconus is a non-inflammatory eye condition characterized by a progressive thinning and steepening of the cornea, leading to a cone-shaped protrusion. In this condition, the normal dome-like shape of the cornea changes, resulting in significant visual distortion and potential impairment of visual acuity. Patients with keratoconus often experience increased sensitivity to light and significant fluctuations in their prescription for corrective lenses.

This condition typically begins during the teenage years or early twenties, and its exact cause is still not fully understood, although it is thought to have both genetic and environmental components. Unlike other eye conditions mentioned, keratoconus does not involve inflammation of the tissues, which is a key differentiating factor.

Episcleritis is an inflammatory condition of the episclera, the layer of tissue between the sclera and the conjunctiva, commonly presenting with redness and discomfort but does not lead to thinning of the cornea. Diabetic retinopathy occurs as a complication of diabetes, affecting the retina rather than the cornea, and involves changes to the blood vessels in the retina. Lagophthalmos refers to the incomplete closure of the eyelids, which can lead to exposure-related issues but does not involve corneal steepening or thinning.