Optical Coherence Tomography Angiography in Pinguecula and Pterygium

To investigate the density of conjunctival blood vessels in normal eyes and in eyes with pinguecula or pterygium.

In this cross-sectional study, the conjunctival blood vessel density of 15 normal eyes, 15 pinguecula eyes, and 15 pterygium eyes of 43 healthy adults was assessed using optical coherence tomography angiography with an anterior segment lens adapter. The nasal surface of each eye (3 × 3 mm) was scanned 3 times to a depth of 800 μm. Conjunctival vessel density was defined as the percent of the scanned volume occupied by vessels in which blood flow was measured.

The high reliability of data measurement was supported by good coefficients of repeatability (<10%) of the image quality score and high intraclass correlation coefficients (>0.9). The vessel density in normal conjunctivas, 52.2 ± 4.1%, was similar to that in pinguecula conjunctivas, 50.5 ± 4.7% (P = 0.3006). However, the vessel density in conjunctivas with pterygium, 63.6 ± 3.7%, was greater than that in either normal (P < 0.0001) or pinguecula (P < 0.0001) conjunctivas.

Using optical coherence tomography angiography with an anterior segment lens adapter, the ocular surface blood vessel density was imaged and assessed with good repeatability and reliability. The blood vessel density of conjunctivas with pterygium was significantly greater than that in either normal or pinguecula conjunctivas. This suggests that, in contrast to pinguecula development, pterygium development includes angiogenesis and neovascularization.