AIM: To investigate the preoperative ocular symptoms and the characteristics of asymptomatic ocular surface abnormalities in hospitalized patients with primary pterygium.METHODS: Cross-sectional study. Hospitalized patients diagnosed with primary pterygium and scheduled to receive pterygium excision surgery at the Xiamen Eye Center of Xiamen University from August 2022 to October 2022 were enrolled. Ocular surface disease index questionnaire(OSDI), six examinations including non-invasive tear film break-up time, Schirmer I test, tear meniscus height, lid margin abnormality, meibomian gland dropout and tear film lipid layer thickness, and anterior segment optical coherence tomography(AS-OCT)were performed and statistically analyzed.RESULTS: A total of 178 cases(178 eyes), with a mean age of 54.39±10.75 years old, were recruited, including 75 males(42.1%)and 103 females(57.9%). The average values of ocular surface parameters in these patients included OSDI: 11.47±9.69, tear film break-up time: 7.10±3.86 s; tear meniscus height: 0.16±0.07 mm, Schirmer I test values: 14.39±7.29 mm/5 min, and pterygium thickness: 504.74±175.87 μm. Totally 161 eyes(90.4%)presented with abnormal lid margin, 44 eyes(24.7%)presented with meibomian gland dropout score ≥4, 52 eyes(29.2%)presented with low lipid layer thickness. In the 6 objective examinations, abnormalities in at least 4 of these tests were found in 85.4% of eyes. Pterygium morphology was classified into four grades: 10 eyes(5.6%)of grade Ⅰ, 93 eyes(52.2%)of grade Ⅱ, 60 eyes(33.7%)of grade Ⅲ, and 15 eyes(8.4%)of grade Ⅳ. In patients with a higher grade of pterygium, the tear film break-up time was lower, and the proportion of abnormal lid margin was also significantly higher(P<0.05). The patients were further divided into two subgroups, including 121 eyes(68.0%)with normal OSDI <13 in the normal group and 57 eyes(32.0%)with OSDI ≥13 in the abnormal group. No significant difference was found in the proportion of meibomian gland dysfunction between the two groups of patients(71.9% vs. 71.9%, P=0.872). In addition, there were differences in the number of abnormal objective examinations(4.11±0.85 vs. 4.91±0.99, P<0.001).CONCLUSIONS: Asymptomatic ocular surface abnormalities were present preoperatively in patients hospitalized for primary pterygium. A comparable high incidence of structural or functional meibomian gland dysfunction existed in pterygium patients with or without apparent ocular discomfort. More attention should be paid to the ocular surface abnormalities in those asymptomatic patients before primary pterygium surgery.