Why do you need an A-scan?
The main application is the calculation of the optical power of an intraocular lens: an error in measuring the length of the eye of just 0.1 mm gives an error of about 0.25 diopters in the final vision. The second important application is to control the progression of myopia in children: myopia grows due to the lengthening of the eyeball, and the dynamics of this length shows the effectiveness of treatment more accurately than diopters. The examination is performed through a closed eyelid or through contact after drip anesthesia.
Why do you need hardware diagnostics?
An examination by an ophthalmologist gives a high-quality picture, while hardware methods provide accurate numbers. They allow us to track the dynamics: whether myopia is progressing, whether the field of vision is narrowing with glaucoma, whether the length of the child’s eye has changed over the year.
Some data cannot be obtained at all during a routine examination - for example, the condition of the retina with a cloudy lens or the exact length of the eyeball for calculating an artificial lens.
Basic methods
- autorefractometry - objective measurement of eye refraction
- computer perimetry - study of visual fields
- Ultrasound biometry (A-scan) – measurement of eye length and structures
- Ultrasound examination of the eye (B-scan) - a picture of the internal environments and retina