Ocular biometry is a diagnostic tool used for taking anatomical measurements of the eye. Human eyes are spherically shaped and placed in bony sockets called orbits. Knowing the details of anatomical measurement of eyes is crucial before any ocular surgeries. The axial length of an eyeball is one of the major determinants of visual disorders. Ocular biometry allows accurate measurements of the axial length of an eyeball and corneal power.
What Is Ocular Biometry?
A-scan (amplitude scan):
What Is the Purpose of Performing Ocular Biometry?
Ocular biometry with the combination of A-scan and keratometry provides broad data and has a wide range of indications. Although it is mainly used before cataract surgery to analyze the parameters of intraocular lens, it also helps in the diagnosis of several other conditions as well. Some of the indications of ocular biometry are as follows:
- Estimation of intraocular lens (IOL) power
- Pseudo exophthalmos
- Phthisis bulbi
- Congenital glaucoma
- Posterior coloboma
Slit-lamp examination is performed on a patient to rule out dense cataracts or other gross problems affecting biometry readings. One can expect keratometry before A-scan while going for ocular biometry as normal saline or anesthetic drops used during the ultrasound may alter the true corneal curvature of the cornea.
Ocular biometry is an advanced tool providing accurate measurements. It helps ophthalmologists to operate on patients with predetermined estimated anatomical measurements. Some of the advantages of ocular biometry are as follows:
What Are the Limitations of Ocular Biometry?
Ocular biometry may need special considerations in some of the cases. Although it provides accurate data, there are several instances that result in the error output. Some of those instances are noted below:
- Posterior Staphyloma
- Inadequate patient fixation
- High Hyperopia dense cataract
- Macular and vitreous ailments
- Pediatric biometry
Ocular biometry is a diagnostic modality used for taking anatomical measurements of the eye including determination of the anterior curvature of the cornea by keratometry, followed by an A-scan ultrasound for taking accurate measurements prior to intraocular lens placement.