The purpose of the study is to explore whether femtosecond laser-assisted cornea epithelial autograft is more effective than limbal conjunctival autograft for ocular surface reconstruction after excision of pterygium.

Inclusion Criteria:

1. Age between 18 to 80 years old;
2. Primary pterygium, scheduled for elective surgical excision;
3. Pterygium encroaching from the nasal side onto the cornea, with less than 180° limbal involvement and without approaching the central visual axis (pupil area);
4. Morphologically intact palisades of Vogt in a given limbal region;
5. Absence of any one of the following structures in the limbal region underneath the pterygium: (1) epithelial basal cells with dark cytoplasm and reflective cell borders; (2) at least two prominent palisade ridge structures; (3) at least one circular and/or oval-shaped focal stromal projection;
6. Informed consent signed by patient or legal guardian; Having the ability to comply with study assessments for the full duration of the study.

Exclusion Criteria:

1. Limbal stem cell deficiency by ocular surface disorders other than pterygium;
2. Inability to determine whether the palisades of Vogt underneath the pterygium is absent or not using in vivo confocal microscopy;
3. High myopia with a spherical equivalent of -15.0 D or less;
4. Corneal or ocular surface infection within 30 days prior to study entry;
5. Ocular surface malignancy;
6. Uncontrolled diabetes with most recent Hemoglobin A1c greater than 8.5%;
7. Renal failure with creatinine clearance< 25ml/min;
8. Alanine aminotransferase > 40IU/L, or aspartate aminotransferase > 40IU/L;
9. Platelet levels < 150,000 or > 450,000 per microliter;
10. Hemoglobin < 12.0 g/dL (male) or < 11.0 g/dL (female);
11. Prothrombin time > 16s and activated partial thrombin time > 35s in patients not accepting anticoagulant therapy; An international normalized ratio greater than 3 in patients accepting anticoagulant therapy;
12. Pregnancy (positive test) or lactation;
13. Participation in another simultaneous medical investigation or clinical trial;
14. Severe cicatricial eye disease;
15. Ocular comorbidities that affect the prognosis of transplantation, such as advanced glaucoma or retinal diseases;
16. Severe dry eye disease as determined by Schirmer's test < 2mm at least in one eye;
17. Any medical or social condition that in the judgement of the investigator would interfere with or serve as a contraindication to adherence to the study protocol or ability to give informed consent;
18. Signs of current infection, including fever and treatment with antibiotics;
19. Active immunological diseases;
20. History of allo-limbal transplantation, penetrating keratoplasty or anti-glaucoma filtering surgeries.