El lensmeter or lensometer is a measuring instrument used in ophthalmology and optometry to measure the prescription of glasses as well as determining the optical center of the lens.
Once the specialist has measured the prescription of the glasses, they can compare it with the prescription that the patient has taken at that time. If the two coincide, we will not have to change the glasses, but if the patient's prescription has increased, we will issue a prescription to update the glass of the glasses with the new prescription.
En Área Oftalmológica Avanzada We invite you to discover what a lensmeter is, what pathologies it detects and what its history is.
What is the lensmeter?
The ophthalmometer is known in ophthalmology by different names, although the most widely used today are a ventometer, a lensometer, a focusmeter or simply a forehead. Any of them refers to the equipment used in optometry to measure the power of the lenses.
El frontofocometer can be automatic o manual. When the examination is carried out with a manual lensmeter, the specialist sees a sheet with drawings of stripes and dots, which blur when the lens to be measured is inserted.
The optometrist will turn the ventometer wheel to refocus the test thanks to a lens system and light sources.
In this way, when the test is correctly focused, a table indicates the optometrist the graduation and obtains the optical center.
Because the measurement is done manually and in fractions of a second, it is necessary to perform various measurements to determine the most accurate graduation.
The digital lensmeter automatically calculate lens power, allowing the optometrist to obtain in less than a minute all the information necessary to obtain the prescription of a patient's glasses.
One of the advantages of the digital lensmeter versus the manual one is that the digital is capable of measuring the graduation of the progressive eyeglass lenses greater accuracy than the manual since this type of lens does not have a uniform graduation throughout the entire lens.
What pathologies does it detect?
The lensmeter is not used to diagnose pathologies, but to measure a series of indicators that are essential for carrying out the ophthalmic glasses.
Through an examination with a lensometer, the optometrist can obtain the following information:
- Effective power of positive or negative spherical lenses.
- Power of cylindrical lenses.
- Cylinder axis.
- Prismatic power.
- Optical center of a lens.
- Power of addition of bifocals.
History of the lensmeter or lensometer
The history of light meters goes back to 1848, when Antoine claudet He made the photographomètre, a tool that was capable of measuring the intensity of the sun's rays in photography.
After the photographomètre, many similar projects and tools were launched on the market, the lensometer The most outstanding.
The first light meter was created with the intention of ensuring focus on photographs. Later, in 1876, Hermann Snellen created the phakometer, a team that could measure optical power and find the optical center of a convex lens.
As early as 1922, the patent for the projection lensometer, the first piece of equipment that was able to project a measured object onto a screen, eliminating the need for refractive error correction and the need to attach a small telescope to the instrument.
Today, there are many brands and models of manual and digital lensmeter. However, the lensometer remains an indispensable tool in the daily work of the optometrist.
En Área Oftalmológica Avanzada we have the latest technology to offer the best diagnoses and treatments. If you haven't examined your vision for a long time, make an appointment with one of our specialists. We are happy to help you!
