The aim of this study is to investigate the relationship between corneal and conjunctival defect areas and postoperative dry eye in patients with pterygium.

Sixty patients (60 eyes) who underwent pterygium excision in Shanxi Eye Hospital between October 2021 and June 2022. Among them, there were 23 males (23 eyes) and 37 females (37 eyes ). with an average of (61.3±6.8) years (ranged from 50 to 70 years). The intraoperative corneal and conjunctival defect areas were measured. Eye examinations were performed before surgery for 3 days and after surgery for 2 weeks, 1 month, and 3 months, including ocular surface disease index (OSDI) scores, breaking-up time (BUT), tear meniscus height (TMH), corneal fluorescein staining (CFS) grade and lipid layer grading. The examination results were represented by subtracting preoperative items from postoperative ones, namely △examination items. Age, corneal defect area, conjunctival defect area, △OSDI score, △BUT and △TMH of patients followed a normal distribution and were described by ±s, and CFS grade and lipid layer grade were ordinal categorical variables that were expressed by frequency and percentile, and CFS grade and lipid layer grading did not follow a normal distribution and was described as a median (interquartile range). The correlation between corneal defect area and conjunctival defect area and OSDI score, BUT and TMH were analyzed using Pearson analysis. The correlation between corneal defect area and conjunctival defect area and CFS grade and lipid layer grade were analyzed using Spearman analysis.

The △OSDI scores of pterygium patients after surgery for 2 weeks, 1 month and 3 months were (21.21±10.65)scores, (13.80±5.30)scores and (3.28±6.92)scores, respectively. △BUT were (-3.92±4.10)s, (-1.80±4.28)s and (-0.49±3.53)s, respectively. △TMH were (-0.15±0.09)mm, (-0.09±0.08)mm, (-0.02±0.05)mm, respectively.The mean median and quartile of the △CFS were 1.00 (1.00, 2.00)grade, 0.00 (0.00, 1.00)grade, and 0.00 (0.00, 0.00)grade, respectively; the mean median and quartile of the lipid layer grade were 1.00(1.00, 2.00)grade, 0.00(0.00, 1.00)grade, 0.00(-1.00, 0.75)grade.The area of corneal defect in patients with pterygium was positively correlated with △OSDI score, △CFS grade and lipid layer grade at 2 weeks after surgery, and the correlation was statistically significant (r=0.659, 0.864, 0.535; P<0.05), and negatively correlated with △BUT and △TMH at 2 weeks after surgery, and the correlation was statistically significant (r=-0.422, -0.492; P<0.05). It was positively correlated with △OSDI score and △CFS grade at 1 month after surgery, and the correlation was statistically significant (r=0.362, 0.737; P<0.05), and negatively correlated with △BUT and △TMH at 1 month after surgery, and the correlation was statistically significant (r=-0.365, -0.354; P<0.05). It was positively correlated with △CFS grade at 3 months after surgery, and the correlation was statistically significant (r=0.395, P<0.05). There was no significant correlation with △OSDI score, △BUT, △TMH and lipid grade 3 months after surgery (r=0.105, -0.085, 0.004, -0.031; P>0.05). The area of conjunctival defect was positively correlated with △OSDI score, △CFS grade and lipid layer grade at 2 weeks after surgery, and the correlation was statistically significant (r=0.544, 0.601, 0.487; P<0.05), and negatively correlated with △BUT and △TMH at 2 weeks after surgery, and the correlation was statistically significant (r=-0.267, -0.540; P<0.05). It was positively correlated with △OSDI score and △CFS grade at 1 month after surgery, and the correlation was statistically significant (r=0.294, 0.586; P<0.05), and negatively correlated with △BUT and △TMH at 1 month after surgery, and the correlation was statistically significant (r=-0.291, -0.427; P<0.05). There was no significant correlation with △OSDI score, △BUT, △TMH, △CFS grade, lipid layer grade at 3 months after surgery (r=0.248, -0.004, -0.239, 0.232, 0.011; P>0.05).

The size of corneal and conjunctival defects during surgery is related to the stability of the tear film after surgery, and the damage to the cornea and conjunctiva jointly participates in the occurrence and development of dry eye after pterygium resection.