Lenticonus is a localized, cone-shaped deformation of the anterior or posterior lens surface. Posterior lenticonus is more common than anterior lenticonus and is usually unilateral and axial in location. Posterior lenticonus is more common but present unilaterally unlike anterior lenticonus, which presents bilaterally. Posterior lenticonus is a common cause of unilateral infantile cataract but is a very rare cause of bilateral cataract.

Anterior lenticonus, which is often bilateral, may be associated with Alport syndrome.

Retinoscopy through the center of the lens reveals a distorted and myopic reflex in both lenticonus and lentiglobus. These deformations can also be seen in the red reflex, where, by retro-illumination, they appear as an ´oil droplet´. The posterior bulging may progress with initial worsening of myopia, followed by opacification of the defect. Surrounding cortical lamellae may also opacity.