Background: Conjunctiva can be restrictive in long-standing strabismus. To date, there are no reports in the literature describing the histology of the conjunctiva in these patients. Methods: Conjunctiva biopsies over the medial and lateral rectus were taken at the time of strabismus surgery in 3 patients with restrictive large angle long-standing esotropia. Results: The conjunctiva overlying the medial rectus has a much more condensed, organized lamina propria compared to the conjunctiva of the contralateral lateral rectus. The medial conjunctiva has scattered small-diameter vessels and numerous clusters of plasmatic cells. The lateral conjunctiva has large blood vessels with occasional scattered plasmatic cells and the lamina propria present a lax structure. Conclusions: These new findings reinforce the clinical understanding that conjunctiva can become more restrictive over the medial rectus in long-standing esotropia.