His work led to much discussion in 16th century Europe over whether the principle organ of sight is the traditional Galenic crystalline humour or the Averroist aranea, which in turn led to the discovery that the retina is the principle organ of sight.

These, however, do not play as critical of a role in vision as the crystalline humor.

The crystalline humor transmits the image it perceives to the brain through an optic nerve.

Other parts of the eye are the aqueous humor in front of the crystalline humor and the vitreous humor at the back.

On an Operation of largely Puncturing the Capsule of the Crystalline Humour in Gutta Serena, London, 1812.

His work led to much discussion in 16th century Europe over whether the principle organ of sight is the traditional Galenic crystalline humour or the Averroist aranea, which in turn led to the discovery that the retina is the principle organ of sight.

To the Philosophical Transactions Sharp contributed two papers in 1753 on 'A New Method of Opening the Cornea in order to Extract the Crystalline Humour,' and in 1754 a paper 'On the Styptic Powers of Agaric.'

In his structure of the eye, the crystalline humor is the part of the eye that picks up the rays from the object and forms a visual cone with the object being perceived as the base of the cone and the center of the crystalline humor in the eye as the vertex.