1. Infective element-lids or lacrimal apparatus

 A. Monilia species
 B. Morax-Axenfeld diplobacillus (angular conjunctivitis)
 *C. Pneumococcus
 D. Pubic lice
 E. Staphylococcus
 F. Streptothrix foersteri

2. Allergic-cosmetic
3. Irritative

 A. Associated infections or irritation of lids, lacrimal apparatus, nose, or skin
 B. Deficiency of lacrimal secretions
 C. Direct irritants-foreign body, mascara, dust, wind, smog, insecticides,  chlorinated water, and many others
 D. Exposure-ectropion, facial paralysis, exophthalmos, and others
 E. Eyestrain
 F. Metabolic conditions-gout, alcoholism, or prolonged digestive disturbances
 G. Overtreatment by drugs-antibiotics, miotics, mydriatics

Fedukowicz HB. External infections of the eye: bacterial, viral, and mycotic, 3rd ed. New York: Appleton-Century- Crofts, 1984.

Geyer O, et al. Phenylephrine prodrug. Ophthalmology 1991; 98:1483.

Okumoto M, Smolin G. Pneumococcal infections of the eye. Am J Ophthalmol 1974; 77:346-352.

Roy FH. Ocular syndromes and systemic diseases, 3rd ed. Philadelphia: Lippincott Williams & Wilkins, 2002.