WTAP and pterygium: Next, using qRT-PCR, we examined the mRNA expression levels of five crucial enzymes needed for m6A modification: METTL3, METTL14, WTAP, FTO, and ALKBH5. We found that the mRNA levels of METTL3 were extraordinarily lower in pterygium versus conjunctive (−0.7155 ± 0.1434, Fold-Change = 0.43728, P-value < 0.0001, Figure 2B).