Diagnostic Precision
Why A-Scan Immersion Mode Matters in Cataract Surgery
Before performing cataract surgery, the surgeon must determine the precise power of the new artificial lens (Intraocular Lens or IOL) to be implanted. This measurement process is called Ocular Biometry. The primary measurement is the eye's axial length—the exact distance from the front surface of the cornea to the light-sensitive retina at the back.
Historically, biometry was done using the Contact (Applanation) method, where an ultrasound probe is pressed directly onto the cornea. However, this pressure physically indents the soft cornea. An indentation of just 0.14mm results in a measurement error that can make the eye look shorter than it is, leading to an incorrect IOL calculation. This often caused a post-operative "refractive surprise," forcing patients to wear strong distance glasses.
The Solution: Non-Contact Immersion Biometry
At Jyoti Eye Hospital, we utilize the superior A-Scan Immersion Mode. In this technique, a small plastic shell containing normal saline is placed over the eye. The ultrasound probe is immersed in the fluid without ever contacting the cornea. This completely eliminates corneal compression, yielding highly accurate, reproducible measurements.
