- Limited measurement range - Inaccurate larger size readings due to curvature of torch - Unable to compare sizing if also using to shine light on pupil
Problems with negative gauge
- Limited measurement range - Difficult to accurately compare white circle with black of pupil. Much easier and faster to compare black circle with pupil
Problems with half-circle gauge
- Difficult to accurately compare a half-circle with a pupil - False readings as half-covering pupil during alignment reduces the amount of light entering eye