Cause of blindness in trachoma -
The later structural changes of trachoma are referred to as "cicatricial trachoma". Rubbing of eye lashes of scarred eye lids against the cornea leads to corneal opacities and scarring and then to blindness. Ref: Parson's 22nd/e p.172-174 & 21st/e p.172-174; Khurana 7th/e p.67 & 4th/e p.62-64
Scarring
pannus
Chronic dacrocystitis
Entropion
Conjunctiva