Purpose The lateral tarsal strip (LTS) for involutional ectropion is often performed with a medial spindle (tarsoconjunctival diamond excision). We aimed to evaluate how well the LTS alone can achieve symptomatic relief. Methods A retrospective, comparative case series was performed on consecutive patients undergoing LTS alone or with medial spindle for involutional ectropion. Outcomes for LTS alone were clinically derived functional success (improvement in symptoms and aesthetic appearance) and anatomical success (judged by punctal position in the tear lake, punctal movement during blinking and absence of ectropion). We verified if these outcomes compared favourably with those of the patients who had undergone an LTS with medial spindle. Procedure selection was based on pre-operative clinical examination, especially the lateral pinch and twist test (this is described). Complications were also recorded. Results Of 67 eyes, 23 had LTS alone and 44 had LTS with a medial spindle. Of those having LTS alone the functional success rate was 87% (95% CI (66.4, 97.2%)). This did not differ significantly from a success rate of 89% (75.4, 96.2%) in LTS with a medial spindle (P ¼ 0.99). A total of 78% (56.9, 92.5%) of patients undergoing LTS had a good anatomical result compared with 82% (67.3, 91.8%) of those who had an additional medial spindle (P ¼ 0.75). Complication rates were similar between the groups. Conclusion Where the lateral pinch and twist test returns the eyelid to a good position, the LTS alone can suffice for the management of involutional ectropion.