Intraoperative semiquantitative keratometry using the keratoscopic astigmatic ruler

Area of Science:

• Ophthalmology
• Optics
• Medical Devices

Background:

• Intraoperative keratometry is crucial for managing corneal astigmatism via suture tension.
• Hand-held keratometers risk errors due to variable measurement distances affecting image shape.
• Accurate measurement requires maintaining a calibrated distance from the astigmatic cornea.

Purpose of the Study:

• To design and evaluate a novel hand-held keratometer for assessing corneal astigmatism magnitude.
• To improve the accuracy of intraoperative astigmatism measurement.
• To provide surgeons with a reliable tool for surgical decision-making.

Main Methods:

• Development of the keratoscopic astigmatic ruler, a hand-held device with a rack of elliptical keratoscopic lenses.
• The device uses inexpensive, autoclavable, injection-molded plastic.
• Incorporation of a sight mechanism to ensure correct measurement distance and a bright corneal reflection.

Main Results:

• The keratoscopic astigmatic ruler generates a clear aerial image above the cornea.
• The design facilitates easy determination of corneal reflection for astigmatism assessment.
• The integrated sight aids in maintaining the calibrated distance for accurate measurements.

Conclusions:

• The keratoscopic astigmatic ruler is an effective tool for measuring corneal astigmatism intraoperatively.
• Its design addresses the distance-dependent error inherent in traditional hand-held keratometers.
• This device offers a simple, accurate, and cost-effective solution for ophthalmic surgeons.