Congenital iris deficiency: complete absence of the iris, with direct visualization of the equatorial rim of the lens, suspensory ligament and ciliary process. There may be photophobia and various ocular abnormalities that cause low vision, and more patients become blind due to progressive corneal and lens clouding or glaucoma. To reduce photophobia, tinted glasses or corneal contact lenses may be worn. So, how do you diagnose congenital iris deficiency? Here is a brief description: The diagnosis can be made clinically. In congenital iris deficient eyes, there is often a residual iris of varying width at the root of the iris, which can also be associated with a variety of eye diseases. The clinical presentation varies because of the degree of iris deficiency, but all have photophobia, frowning and squinting and may have progressive vision loss associated with iris deficiency, macular central hypoplasia, corneal opacification, cataract glaucoma and refractive error. In some eyes, the residual peripheral iris is visible with a flashlight or slit-lamp examination, while in others, the residual iris root tissue can only be seen under an atrial angle lens. A higher proportion of patients have peripheral corneal opacification and corneal clouding early in life, which progresses to the central cornea with age. Occasionally, microkeratoconus, corneal sclerosis, and corneal-lens adhesions are seen. Lens developmental abnormalities are more common with congenital restrictive lens clouding, or with ectopic or congenital defects of the lens. The development of progressive cataracts can result in significant vision loss. The absence of iris can also be associated with choroidal defects, pupillary remnants, small optic nerve papillae, strabismus, and ptosis, and can lead to nystagmus if associated with macular center dysplasia. It should be differentiated from acquired iris damage.