评估 0.5% 5-氟尿嘧啶 (5-FU) 局部治疗眼表面鳞状细胞瘤 (OSSN) 的疗效，并评估接受治疗的患者的耐受性。临床诊断为 OSSN 的患者转诊至眼肿瘤科来自巴西圣保罗联邦大学的部门被招募来进行当前的研究。患者接受局部 5-FU 0.5% 治疗，每天 4 次，持续 10 天，然后进行为期 3 周的药物假期，持续最多 3 个周期，然后进行替代治疗。在基线和整个治疗过程中对病变进行评估。使用Morisky 药物依从性量表评估治疗依从性。记录治疗过程中的任何不良事件。该研究纳入了 30 名坚持治疗的患者的 30 只眼睛。在接受5-FU 0.5%治疗的所有病例中，有24例患者在平均治疗时间21.71±7.77天后获得治疗成功，成功率为80.00%（95% CI：60.75-91.18%）。病灶面积每增加 1 mm2，治疗成功的几率就会降低 6%（OR：0.94；95%CI：0.88-0.99；p = 0.033）。 8例患者在治疗过程中仅观察到眼部不适、眼部烧灼感和流泪等轻微不良事件。外用5-FU 0.5%是治疗OSSN的有效治疗选择，治疗成功率高达80%，显示出良好的耐受性。病变的大小被认为是影响治疗成功的因素，因此在确定治疗方法时应予以考虑。

To evaluate the efficacy of topical treatment with 5-Fluorouracil (5-FU) 0.5% in cases of Ocular Surface Squamous Neoplasia (OSSN), and to assess the tolerance of patients undergoing treatment.Patients with clinical diagnosis of OSSN referred to the Ocular Oncology division from the Federal University of Sao Paulo, Brazil, were recruited for the current study. Patients were treated with topical 5-FU 0.5% using a regimen of 4 times daily for 10 days, followed by a 3-week drug holiday, continued up to 3 cycles before an alternative treatment. Lesions were evaluated at baseline and throughout treatment. Treatment adherence was assessed using the Morisky Medication Adherence scale. Any adverse events along the treatment were noted.A total of 30 eyes of 30 patients adherent to the treatment were included in the study. Among the total cases treated with 5-FU 0.5%, 24 patients achieved therapeutic success after a mean treatment duration of 21.71 ± 7.77 days, representing a success rate of 80.00% (95% CI: 60.75-91.18%). For each 1 mm2 increase in the lesion area, the odds of treatment success decrease by 6% (OR: 0.94; 95%CI: 0.88-0.99; p = 0.033). Only mild adverse events such as ocular discomfort, ocular burning and tearing were observed along the treatment in 8 patients.Topical 5-FU 0.5% is an effective therapeutic option in the treatment of OSSN, with an 80% therapeutic success rate, showing good tolerability. The size of the lesion was identified as a factor influencing treatment success, therefore it should be taken into consideration when defining treatment approaches.