As an undergraduate in the 80s I was lucky enough to speak with one of the pioneers of optometry, American optometrist and engineer Irving Fatt. This expert in corneal physiology stated “the only way to truly measure IOP is to drill a hole in the eye and measure the fluid directly”. Knowing the cornea as well as he did, he believed that flattening the cornea will guide us to the IOP but that applanation tonometry gives an approximation at best. Therefore it’s hardly surprising that measuring corneal thickness has become as important to today’s optometrist as performing tonometry. Obviously we can’t go drilling holes in our patients’ eyes, but the combination of applanation and pachometry now gives us a much better idea of the true IOP. Traditional tonometry alone obviously exaggerates IOP where the cornea is thick and underestimates IOP behind thinner corneas. My best analogy to support this is  comparing balloons with volleyballs. Each may have equal internal pressure, but the force required to applanate the thicker volleyball will be much higher than for the thinner balloon.

When Optical Manufacturers decided to include the Sonogage Corneo-Gage Plus Pachometer in our range of premium optometric equipment, we were mindful of the needs of the practitioner: design excellence, simplicity, ease of use, accuracy and quality of manufacture. The Corneo-Gage Plus is the definitive instrument to measure corneal thickness. The design of the instrument has cleverly taken most of the components away from the patient’s face so that the smooth lightweight probe is easily held to take measurements with no risk of corneal abrasion. The state-of-the-art 50MHz transducer ensures that measurements of corneal thickness are quick, reliable and extremely accurate. The probe is simple to clean and the internal power supply makes the whole unit completely portable.

Now it has become essential for optometrists to measure corneal thickness as well as performing tonometry, the pachometer allows us to carry out the necessary calculation of adjusted tonometry readings with simplicity to give a much more reliable value for patients’ IOP. It is this capability that takes the guesswork out of glaucoma screening and makes the Corneo-Gage Plus an indispensable tool for optometrists to provide the highest level of patient care.

The Sonogage Corneo-Gage Plus – now available exclusively from Optical Manufacturers Pty Ltd, Australia’s leading supplier of premium optometric equipment.

Lee J  Pepper
B.Optom. (Hons) UNSW