Contact Lens Basics

How To Convert A Glasses Prescription Into Contacts?


If you wear both- contact lenses and glasses alternatively, you must have noticed that there is a slight difference between their prescriptions. The glass-wearers are often confused whether their regular prescription for glasses work for the lenses too. Well, the process of conversion of a glasses prescription into lenses prescription or vice-versa is a little complex. Therefore, this delicate matter should be handled with care and an optician should be consulted for the same.

However, here is how a glasses prescription is converted into lenses prescription:

* Check your glasses prescription and you will find two categories- OD and OS. Here, OD refers to right eye and OS refers to the left eye. Each abbreviation is followed by a number that is in diopeters specifically written as D. A prescription that is marked DS states diopters sphere, which actually means that the user doesn't have astigmatism. + and - are used for numbers that follow the abbreviation. - sign means nearsightedness whereas +sign indicates farsightedness. Now, if the patient is suffering from astigmatism, the first number will be followed by the second number that also determines the severity of the condition.

* Different positions of the lens should be taken into account. Your glasses are placed a few millimeters away from the eye whereas the contact lenses are applied directly on the eyelid. Therefore, you would need to show your prescription to the optometrist so that you can get to the actual power difference. Various factors make a difference to your prescription and it is quite true in the cases where the prescription is usually higher than +/- 4D.

* In case you wear hard contact lenses, Astigmatism does not need any consideration. A hard contact lens corrects the shape of the eye and makes it somewhat spherical. Therefore, the strength of the lens would be same as the prescription of your glass.

* If you wear soft contact lenses, take astigmatism into consideration. 'Toric' is what you require in this condition. If you have .75D astigma, you will require differently shaped soft contact lenses. In this case, patients suffering from severe astigmatism should prefer using hard contact lenses.

* Finally, visit your optician or a good eye specialist. Make sure you have studied your prescription quite well. Other factors such as eye health conditions, curvature of the eye as well as other factors would be determined by the specialized machines.

Thus, you can convert your glasses prescription into one for contact lenses. However, medical advice and supervision is always recommended due to presence of a few factors that could be completely understood and handled by a trained eye care professional himself.