Visual acuity, spectacle blur and slit-lamp biomicroscopy on asymptomatic contact-lens-wearing recruits.

Refraction data of 644 Dutch Army and Air Force recruits wearing contact lenses or spectacles were statistically compiled and correlated with the type of lenses worn. Visual acuity with contact lenses was far from optimal because the power of the lenses was incorrect or the optical quality poor. This applied particularly to soft contact lenses. On the other hand, spectacle blur was rare with soft lenses and less evident with gas-permeable hard lenses compared with conventional hard lenses. Less corneal staining occurred with gas-permeable hard lenses compared with conventional hard lenses (P=0.02). Corneal neovascularization, conjunctival hyperaemia, papillary changes in the tarsal conjunctiva, corneal opacifications and ghost vessels were seen more often in wearers of soft rather than hard lenses. In this study, in which we examined objective parameters of contact lens efficiency, the gas-permeable hard lenses appeared most favourable.