The anterior limiting lamina (Bowman's layer) is directly below the epithelium. It is a thin acellular (no cells) layer of the extracellular matrix protein collagen. It was originally named after Sir William Bowman (1816-1892) an English ophthalmologist, anatomist and physiologist. No one really knows the purpose of Bowman's layer, and in fact many species and people who have had photorefractive surgery (PRK) get along perfectly well without it.
The conjunctiva is a thin membrane that covers the sclera (white part of the eye) and the inside of the eyelids. It is composed of two layers, the epithelium and the stroma. The epithelium is the outermost layer and has 2-4 layers of epithelial cells. Interspursed among these cells are goblet cells. These secrete a substance called mucin that becomes part of the tear film. The stroma is a layer of fibrous tissue that contains blood vessels and cells such as mast cells. In allergic individuals on exposure to allergens such as pollen, the mast cells secrete chemicals that cause itchiness and tearing.
The tear film covers the outer surface of the eye. It is estimated to be about 7um thick (although there is still much debate about this) and has three main components (it was though that there were 3 distinct layers, but now it seems that the 3components are blended together rather than being separated). There is an oily lipid component which helps reduce the rate of evaporation of tears from the ocular surface. The constituents of this part are secreted by the tarsal (Meibomian) glands which are present in the eyelids. There is an aqueous component. The constituents of this layer are secreted by the lacrimal gland and accessory lacrimal glands. Finally there is a mucin component which helps spread the tears evenly over the surface of the eye. The constituents of this component are secreted by the goblet cells of the conjunctiva and the epithelial cells of both cornea and conjunctiva.