Phoroptor: A brief introduction

Phoropter_Ezer_EDR_5200_Ophthalmic_equipmentPhoroptor is one of the many instruments that are used by an optometrist at the time of examining an eye. The refractive error of a patient can be measured by this instrument, which then helps in determining the type of lens suitable for the patient.

This machine is used only when the doctor figures out that you are having such problem like astigmatism or nearsightedness. The device comes with a lens- series and when using it, the optometrist will be switching these lenses and will be doing some necessary settings. The optometrist, meanwhile, will be getting feedback from his patient that will help him in providing the best possible vision.

The device’s main function is in determining the way in which the lens is required to be curved. This is referred as refraction and explains why phoroptor involves the process of switching lenses.

At the time of using this machine, the patient is asked to sit comfortably behind this instrument and look through it. The machine places a chart at a distance of around 40cm from the eye of the patient. After the patient takes his seat, the doctor starts changing the lenses as he receives the patient’s feedback. The patient is required to answer the various questions thrown to him by the doctor whenever he changes the lens.

Phoroptor can be also used with other instruments as well. These include retinoscope and automated refractor. Other than that, phoroptor is used in determining the eye’s normal resting position along with the accommodative posture, amplitude, horizontal and vertical vergences.

After the optometrist takes down the measurements, he then will be prescribing the right eyeglass. It is likely that this prescription will be containing six numerical terms. These are the cylinder, sphere and axis. Cases are also there where the optometrist writes down the papillary distance as well.

The phoroptor comes with lenses that refract light. This helps in focussing the images right on the retina of the patient. Perfect vision can only be provided if the optometrist can determine the spherical power, cylindrical axis and cylindrical power.

Refraction can be measured both manually and automatically. Nowadays, the market even offers digital phoroptors. There are technologies that can automatically measure refraction index. Perfect example is the autorefractor. The optometrist is the only person who can determine whether the prescription can easily be identified using phoroptor. Phoroptor is a comfortable and safe machine that can determine the eyeglass prescription accurately.

Author Bio: Tony Rollan provides marketing service for VSI ( and he is an author of many articles on all types of optical and ophthalmic equipment. Author talks about medicine,  health, alternative healing, sport and well being.

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