Soft contact lenses do not influence IOP measurements

Silicone hydrogel soft contact lenses do not significantly affect IOP measurements with non-contact tonometry (NCT), claims a study in the journal Eye.

The investigation, led by Dr P.G. Firat, Deparment of Ophthalmology, Turgut Ozal Medical Centre, Inonu University, Malatya, Turkey, included 40 eyes of 40 patients. The IOP values of each patient were gathered using NCT in patients with and without contact lenses - group 1 and 2, respectively. The remaining patients were measured with Pascal dynamic contour tonometry (DCT) with and without contact lenses - group 3 and 4, respectively. The last group consisted of patients measured by Goldmann applanation tonometry (GAT) without contact lens.

Group 1 demonstrated a mean IOP value of 14.55±2.95 mmHg, compared to 13.92±2.58 mmHg in group 2. Mean IOP values for group 3 and 4 were 16.26±2.33 mmHg and 15.19±2.40 mmHg, respectively.

A statistically significant difference was found between groups 3 and 4. It was also found that mean IOP value in group 5 was 12.97±2.65 mmHg, revealing that IOP values measured with DCT produced statistically significantly different results than IOP values measured with NCT and GAT.

IOP values measured with NCT were significantly higher than those measured with GAT. Wearing silicone hydrogel soft contact lenses can affect IOP values measured with DCT.