Many extreme eye diseases in Sri Lanka may not have any visible early warning devices. A routine eye examination is thus of great value in ensuring good eye protection and forewarning of potential hazards.
A biometry test is the mechanism by which the power of the cornea (keratometry) and the length of the eye are measured, and the optimal intraocular lens power is calculated using this data. Patients will be left with a large refractive error if this measurement is not done, or if it is incorrect.
The cloudy, normal lens was removed from the eye during cataract surgery. In most cases, by replacing it with a permanent intra ocular lens (IOL) implant, the focal power of the natural lens is returned. The strength of the intra ocular lens should be determined in accordance with this. The method of measuring the strength of the IOL is called optical biometry.
Keratometry Readings (Diopteric Power of the Cornea) are the two key readings needed to measure the IOL power. Axial Length (Axial Length Distance from the Cornea to the Retina) Qualified Optometrists, Ophthalmic Technologists & Ophthalmic Assistants perform this exam.
Methods of biometry tests
Opticians in Sri Lanka use an immersion technique, touch technique or using IOL Master, ophthalmic biometry examinations may be performed. High-quality IOL Master-optical biometry mechanism and the other procedures are available for this test at vision care and we are proud to be the first optical organization without a waiting list to facilitate A ‘scan service to the public.
Ultra sound immersion
The patients are positioned in a supine posture on a flat exam table or in a reclining exam chair in Immersion A ‘scan biometry and a drop in local anesthetic is added to both eyes. A shell of sclera is then added to the eye. The shell is packed with a solution from BSS. In the shell, 5 to 10 mm away from the cornea, the ultra sound probe is immersed in the solution. The patient is asked to look at a fixation point set on the ceiling for the other side. On the screen, attention is then focused. Until the probe is correctly aligned with the optical axis of the body, the shell is attached to the sclera and an appropriate A ‘scan echogram is seen on the screen.
Contact method
The patient is checked in the chosen place by using the touch process, and a drop of local anesthetic is installed in both eyes. The ultra sound probe is allied with the visual axis and a light within the probe is needed by the patient to correct it. The probe is then immediately touched by the cornea to create the echo pulse.
IOL master
It is gradually becoming evident that with ‘Carl Zeiss Meditech IOL Master' using the 4th generation immersion biometry program, the most precise way to calculate AL. To measure axial duration, the IOL Master uses light rather than tone. The Al measuring technology implemented in this groundbreaking method is based on the partial coherence interferometry theory of optical biometry. As there is almost no touch with the ears, the IOL master is incredibly user-friendly. Using standard international biometry formulas, the IOL master allows IOL data to be measured and the lens type chosen from a database.
Applanation (Contact) is the most common way of measuring AL. However, because this is performed by a highly trained technician, because of corneal indentation, it continues to create myopic surprises.
Any surgeon seeking to achieve excellent distance vision for patients with accommodating or multi-focal lenses is believed to turn to the IOL master or immersion biometry for AL measurements as soon as possible. K'reading is often better taken manually or from the IOL master.
In ocular biometry, partial coherence interferometry has become the gold standard as it is extremely precise, simple to do, non-invasive and convenient for the patient. Through a broad variety of experimental tests, the precision of optical biometry, and in particular the IOLMaster, has been thoroughly verified. The biometrics test is performed on patients with cataract s prior to cataract surgery in the IOl buying phase, patients expecting to undergo a refractive surgery conducted at the request of an eye surgeon for biometry & at the request of an eye care professional or an ophthalmologist or eye surgeon in a situation where measuring of axial length, K reading or ACD is required.
