What is a possible reason for not having eye lashes?

No eyelashes. There are several reasons for no eyelashes. Some people have a condition called trichotillomania in which they constantly pull at their hair, eyebrows or eyelashes. Repetitive trauma can scar the hair follicles and cause permanent hair loss. There also is an autoimmune disease called alopecia areata and universalis in which antibodies attack hair follicles.
Many reasons. This is known medically as madarosis & is defined as hair loss of the eyebrows or loss of eyelashes (milphosis). When this occurs it may be the 1st sign of an underlying systemic cause. Inflammatory disorders including bacterial & fungal infections, autoimmune, endocrine, congenital, drug related or psychiatric  disorders can be potential causes.  see your dermatologist or ophthalmologist.