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1 December 2000


The corneal diameter has a formidable influence on the sagittal height of the anterior eye. Typically, practitioners use the sole measurement of keratome try readings in an attempt to accurately predict the proper inner sagittal depth of a contact lens. However, the sagittal depth of the anterior eye is influenced by other anatomical factors such as corneal asphericity, curvature of the paralimbal sclera and the corneal diameter. The Irisometer, an instrument used to measure the horizontal visible iris diameter, was developed with the intentions of incorporating the simplicity of the hand-held ruler along with the accuracy of the slit lamp based reticule. The Irisometer was tested on 35 subjects, which revealed favorable test results showing the Irisometer to be both accurate and simple to use. The measurement of the horizontal visible iris diameter has an important contribution to successful contact lens fitting. It is therefore concluded that the contact lens practitioner would benefit from having the Irisometer in his armamentarium in order to obtain quick and accurate measurements of the corneal diameter.


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