AIM: To investigate the differences of clinical signs and pathological structure of unilateral nasal pterygium and unilateral double pterygium

METHODS: Retrospective study. Totally 11 unilateral nasal pterygium and 11 unilateral double pterygium were collected to observe the size of the tissue area, the classification of blood vessels, the transparency and the break-up time of tear film. The 11 surgically excised double pterygia(11 eyes)and 6 samples of normal conjunctiva were collected for the study. With 40g/L paraformaldehyde fixation, paraffin sections were stained with Haematoxylin-Eosin, to observe the differences with nasal and temporal pathology under light microscope.

RESULTS: In unilateral double pterygium, the tear break-up time was significantly shorter than that of unilateral nasal pterygium(t=3.410, P=0.003). In unilateral nasal pterygium, there was a significant negative correlation between tear film break-up time and tissue size(r=-0.927, P<0.01)and transparency(r=-0.764,P<0.01). In unilateral double pterygium, the tear break-up time was significantly negatively correlated with the growth time(r=-0.661, P<0.05), tissue size(r=-0.775, P<0.01)and transparency(r=-0.671,P<0.05). In unilateral double pterygium, compared with the temporal side, the quantity of the layers of corneal epithelial cells(t=-7.351, P<0.05), vessels(t=-7.400, P<0.05)and inflammatory cells(t=-7.481, P<0.05)increased.

CONCLUSION: Compared with unilateral nasal pterygium, the tear film break-up time of unilateral double pterygium was poor. In unilateral double pterygium, with high activity, the degree of proliferation of squamous epithelium, hyperplasia and inflammatory reaction are significantly higher than those of the temporal side.