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Abstract #10330 Published in IGR 6-1
Non-contact tanometry over soft contact lenses: effect of contact lens power on the measurement of intra-ocular pressure
Patel S; Illahi WContact Lens and Anterior Eye 2004; 27: 33-37
PURPOSE: To perform non-contact applanation tonometry over soft contact lenses and to examine any differences between the measured intraocular pressure (IOP) with and without the contact lens. METHOD: IOP was measured at one eye of eight subjects and re-evaluated through a soft lens in situ over the cornea. Seventy percent (ES70, Lunelle) water contact lenses or powers ranging from -15.00D to +13.00 D were used. RESULTS: Mean IOP without lenses was 15.2 mmHg (SD: ± 4.2) and this did not change significantly for lenses ranging from -15.00D to +3.00 D (p > 0.01) but did change for lens powers +6.00D and above (P < 0.01). The least squares line describing the change in measured IOP (δ IOP) as a function of lens power (x) has the following characteristics, δ IOP = 0.022 + 0.591x +0.11x2 +0.005x3 (r = 0.985, p = 0.0001). CONCLUSIONS: Non-contact tonometry can be performed with sufficient accuracy over a soft lens on condition: (a) lens center thickness is no more 0.30 mm and (b) power is not greater than +3 D.
Dr. S. Patel, Practitioner Services, Common Services Agency, NHS Scotland, South Trinity Road, Edinburgh EH5 3SG, UK
Classification:
6.1 Intraocular pressure measurement; factors affecting IOP (Part of: 6 Clinical examination methods)
