Lenticonus is a localized, cone-shaped deformation of the anterior or posterior lens surface (Fig 4-4). Posterior lenticonus is more common than anterior lenticonus and is usually unilateral and axial in location. Anterior lenticonus, which is often bilateral, may be associated with Alport syndrome.
In lentiglobus, the localized deformation of the lens surface is spherical. Posterior lentiglobus is more common than anterior lentiglobus and is often associated with posterior pole opacities that vary in density.
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 retroillumination, they appear as an “oil droplet.” (This condition should not be confused with the “oil droplet” cataract of galactosemia, which is discussed in Chapter 5.) The posterior bulging may progress with initial worsening of the myopia, followed by opacification of the defect. Surrounding cortical lamellae may also opacify.