Effect of contact lens materials and corneal biomechanical properties on intraocular pressure in neophyte soft contact lens wearers

Purpose: Contact lenses are one of the main options of refractive error correction. The aim of this study was to determine the effect of soft contact lens wear on intraocular pressure in normal eyes. Materials and methods: This was a longitudinal interventional clinical trial conducted at University of Minho, Portugal. Goldmann correlated intraocular pressure (IOP) was measured by Ocular Response Analyzer in 58 normal eyes of 29 subjects that had never worn contact lenses before. Subjects were fitted with daily disposable (Nelfilcon A or Stenofilcon A) lens on one eye and monthly disposable lens (Lotrafilcon B or Comifilcon A) on the other eye in random manner. Measurements of IOP were repeated every month during three months of contact lens wear. Changes in IOP were analyzed. Effect of contact lens materials and corneal biomechani-cal properties [corneal resistance factor (CRF) and corneal hysteresis (CH)] on the changes of IOP were also studied. Results: IOP was reduced by 2.5±2.5 mm Hg after three months of contact lenses wear (p<0.001). During the first month, IOP was reduced by 1.1±2.4 mm Hg (p=0.006) and in the second month by 1.0±2.4 mm Hg (p=0.009). However, during the third month, the IOP reduction was 0.3 mm Hg, which was statistically nonsignificant (p=0.486). The change in IOP was correlated with lens material (p=0.013) and was maximal with Comifilcon A. Changes in IOP correlated positively with both CRF (p<0.001) and CH (p=0.023). Conclusion: Soft contact lens reduced the IOP during three months of lens wear in neophyte contact lens wearers. IOP reduction was higher with Comifilcon A lens. Eyes with high corneal biomechanical properties had greater IOP reduction. A study with a larger sample size and longer duration is necessary to confirm this finding.