**2. Simple excision of pterygium**

It reported that the stability of the tear film after pterygium resection is reduced, and dry eye syndrome occurs in severe cases [5]. Compared with preoperative, the tear break-up time (BUT) was significantly prolonged for 1 month after scleral exposure with simple pterygium excision. Tear-ferning test showed a significant increase in normal crystallization ratio, and conjunctival imprint cytology showed a significant increase in goblet cell density. Therefore, they thought that tear function in patients with primary pterygium improves after pterygium excision, which

indicates that pterygium has a close relationship with dry eye [6]. However, there was other studies concluded that pterygium removal may not have any effect on Schirmer's test results and tear BUT 1-month post- surgery [7]. Paton observed that a pterygium is further exacerbated by elevation of the pterygium head, dryness, and delle formation [8]. Pterygium excision can partly restore the tear functions into normal state in patients with pterygium which may be due to the increasing density of the conjunctival goblet cell and the recovery of mucus secretion [9]. Simple excision of pterygium is a traditional surgical method, but the recurrence rate is as high as 24–89% [10], and it is currently less applied.

## **3. Pterygium excision combined with autologous conjunctival transplantation**

Kilic et al. [11] investigated the effects of pterygium excision using the limbal conjunctival autografting technique on the tear function tests in 14 eyes of 13 patients. Since no difference was found in the Schirmer and tear BUT tests at 1 and 6 months postoperative versus preoperative. Shortened BUT and the reduced length of Schirmer test after the removal of pterygium combined with autologous conjunctival transplantation are related to the number of operations, the size of the scleral exposed surface, the thickness of the graft, and the location of the graft. Large removal of the nasal conjunctiva intraoperatively, too large conjunctival graft, and the location too close to the dome or too deep can all lead to shortened BUT, reduced tear secretion test length, and prone to dry eye syndrome [12]. Some authors [13] have found that compared with the opposite healthy eyes, the BUT and mucus fern test (MFT) in the eyes with pterygium were significantly different before the operation (p < 0.05). The results of the BUT and MFT in the eyes with pterygium were significantly different before and 4 weeks after the operation (p < 0.05). The BUT was prolonged and the ratio of normal crystallization in the MFT increased. Tear functions were abnormal in the eyes with pterygium. Pterygium excision combined with conjunctival autograft transplantation can partially restore the tear film function into normal state, and the tear film function was stable 4 weeks after surgery. Zeng et al. [14] compared the recurrence rates after pterygium excision combined with autologous conjunctiva and amniotic membrane transplantation. After 1 year follow-up, the results showed that the combined autologous conjunctival transplantation group was lower than the amniotic membrane transplantation group, and the difference was statistically significant (p < 0.05). No statistically significant difference was observed between the two groups in postoperative tear film BUT (p > 0.05).
