Bandage lenses: collagen shield vs. hydrogel lens

We compared the behavior of a 70% water content hydrogel lens to a 24-hour collagen shield in 11 healthy volunteers. Corneal swelling was measured by means of ultrasound pachymetry. After 24 hours of continuous wear, mean corneal thickness increased 26.4 microns (4%) with the hydrogel lens and 17.9 microns (3%) with the collagen shield, a difference that was not significant at the P less than 0.05 level. Both the hydrogel lens and the corneal shield were well tolerated. Ocular discomfort was slightly greater with the collagen shield. We assume that this is related to the reduction in visual acuity and subsequent loss of binocular vision with the collagen shield. The development of a fully transparent collagen shield would enhance patient compliance and facilitate assessment of the corneal and intraocular status in eye disease.