1. Pterygium and Visual Aberrations
Associate Professor Kosol Kampitak, M.D.
Deparment of Ophthalmology
Faculty of Medicine
Thammasat University
Pathumthani, Thailand

2. Pterygium
- Pterygium is a disease of the ocular surface with a wing-shaped growth of fibrovascular tissue on the corneal surface.

3. Pterygium
The occurrence of pterygium is associated with long-term ultraviolet light exposure.
Though it's commonly called “Surfer’s eye”
(Reflection of sunlight on water)

4. In advanced cases, impaired vision can occur as a result of pterygium growing directly to cover the pupil.
Pterygium may cause visual impairment indirectly by inducing pressure and distortion on the corneal surface leading to optical aberrations.

5. Optical aberrations are generally composed of two major components known as
lower order aberrations --

6. Optical aberrations are generally composed of two major components known as
lower order aberrations --
and
higher order aberrations --

9. The axis of corneal astigmatism was found in
The diopter of corneal astigmatism ranged from 0.10 diopter to diopter (1.86 +/- 2.39).
The axis of corneal astigmatism was found in
vertical axis 156 eyes (64.2%)
oblique axis 36 eyes (14.8%)
horizontal axis 51 eyes (21.0%)
The degree of corneal astigmatism significantly correlated with the extension of pterygium (size) on the cornea (R Square = 0.45, p < 0.001).
When the extension of pterygium exceeded 2.25 mm, there was a chance of developing corneal astigmatism of 2 diopter or more
(86.21% of sensitivity and 80% of specificity).

12.  higher order aberrations have a tendency to increase in pterygium eyes compared to contralateral normal eyes
most have a correlation with pterygium size