Part 2 - Solving Problems and Adaptation Eyeglass Sale

Part 2 - Solving Problems and Adaptation Eyeglass Sale

Article written by Paulus Maciel.  Rights Reserved.

Here we are to start the first item that may hinder the sale or adaptation of an eyeglass consumer, the dreaded "thick lenses." Whenever one approaches the subject "thick lens" arises famous thick lens calculations. I would like to ask your permission to conduct this matter without using this calculation. I propose a more agile approach to preventive and optimal terms of thickness results in the final product. All this based on over 12 years of experience from solving problems of adaptation. this and the other matters, I'm using the very method of "preventive sale" that is, everything that can go wrong after the sale of the glasses is eliminated during sale of the same, through the processes of history taking, examination prescription, frame choice, choice of lenses and taking action. preventive Thinking on sale, the four aspects that influence the thickness of the lenses are:

1. Choice of frame
2. Prescription versus refractive index
3. Inaccurate measures of the rim
4. Glasses previous decentered

We'll cover in a very objective each of these four aspects, starting with the choice of frame.

Pictured below is an example of poorly chosen frame, where we can see the lack of centralization of the lens relative distances of the individual pupil.

In another photo, we can see a better centering of the lens relative distances of the model pupil. This point is fundamental to the proportional reduction of the thickness of the lenses, the centralization of the frame in the user's face.

Let me give you some practical examples of centralization of the frame using a model of acetate with the following measures:

• Bridge = 22mm
• Aro = 47mm
• Biggest = 47mm diagonal
• Vertical Rim = 36mm

In this first example, we use a ready CR39 lens with +6.00 spherical mounted "frame" model with a 35mm DNP in both eyes. Mounting height centered.

The value of the sum of the bridge + frame rim is 69mm, that is, a value of measurement of PD. This approach measures centered lens to the rim, causing the center to 7.8mm stay in center of ring and also distributes the thickness between nasal and temporal portion of the frame.

Although both edges being left with an elevation of 4.6mm, has the edge of ethyl 4,5 mm, which disguises very leaving the final appearance very interesting.

In this second example, we use the same CR39 lens prepared with spherical +6.00 mounted on the "framework model" with a DNP 30mm in both eyes. Mounting height centered.

The value of the sum of the bridge + frame rim is 69mm, that is, a value larger than 9mm DP. This inequality of measures made the lens would not be centered on the rim, leaving the center thinner than the previous example but with a high nasal 6mm, that is, thickness 30% more than the previous example. The final result showed a lens much thicker than that on the nasal and temporal. Glad that the frame has no nameplate, but the same adjustment would be difficult.

In this third example, we use a CR39 lens prepared with spherical -6.00 mounted on the "framework model" with a  DNP 35mm  in both eyes. Mounting height centered.

The value of the sum of the bridge + frame rim is 69mm, that is, a value of measurement of PD. This approach measures centered lens to the rim, causing the center to 2.2mm stay in center of ring and also distributes the thickness between nasal and temporal portion of the frame.

Both edges were at a thickness of 5.6mm, this lens is 1.1 mm away from the edge of acetate having 4.5 mm. If the editor is "beast" will be difficult leftovers lens off the rim. In short, a great result thick, even for a CR39 with 6.00 diopters spherical negative.

In this fourth example, we use the same CR39 lens prepared with spherical -6.00 mounted on the "framework model" with a  DNP 30mm  in both eyes. Mounting height centered.

The value of the sum of the bridge + frame rim is 69mm, that is, a value larger than 9mm DP. This inequality of measures made the lens would not be centered on the rim, leaving the center thicker (2.4 vs. 2.2) than the previous example and a thickness of 7.4mm time, that is, 32% more thickness than the previous example , leaving about 3mm lens out of the rim. Here comes the famous "Coke-bottle".

In these four examples, we reached the conclusion that a good lens thickness depends on the choice of a frame centered on the user's face. It does not help sell a lens with refractive index 1.67 or 1.74 and offer a frame without centralization. Always remember that refractive index is no guarantee of thin lenses, but the choice of the frame.

In practice this concept can preventive sale, measuring the DP client with pupilometro and thereafter, select frames where the sum over the rim of the bridge is as close as possible to the DP it.

Some optical already follow this model of preventive sale, separating the frames in drawers measured by the bridge over the rim. Thus, simply measuring the DP client and go to the corresponding drawer frames more appropriate.

The second aspect we need to consider is the coherence between the prescription and the refractive index of the lens. 

One of the first things we learn in optics is "the higher the refractive index, the thinner the lenses are." This statement is true only when these lenses are compared on the same diameter, that is, refractive index does miracle in glasses, he is just the complement of a well-chosen frame.

When choosing the right frame, we can choose an index of refraction that is consistent with the prescription presented. Based on my practical experience, I present to you a table that will assist them in choosing the index according to diopters for maximum performance thick.

Many opticians are unsure if surfassagem can make a difference in the thickness of a lens.That depends on the diopter.

If the diopter is positive, surfassagem an index block consistent with the diopter can bring a best result in thickness relative to a lens prepared with the same index. For optimal result thick, use surfassagem in positive income from 2.50 diopters Remember to choose the right frame (bridge + aro equal or very close to the DP). 

If the diopter is negative, surfassagem will not bring differential thickness lens in relation to a purchase of the same index. In the only negative lenses and frame rate make the difference.

The third aspect that may hinder the final thickness of the lens is perfectly fulfilled when the above steps, but the time to write down the measurements of the frame in order, make mistakes in measuring the rim.

The measurements of the ring are crucial in the calculation that will determine the reduction in the diameter of the block surfassagem. If these measures are taken the wrong way, the thickness of the lenses will be compromised.

The Hoya has a fantastic guide that teaches you how to do it correctly measure the frame.Follow the image below it (low resolution). You can also download the pdf file of information with high image quality, just click the following link: http://www.lenteshoya.com.br/optico/downloads/tomadas_de_medida_lifeStyle.pdf

The room is the last aspect that can influence is when the previous customer's glasses with lenses is super thin not because of the choice of frame and content, but by the DNP was set out purposely to reduce the thickness of the assembly.

There are two points to note, since the first is knowing when the client is using a glasses off your DNP. If the customer is using more than a year, he will surprise a glasses again with DNP mounted right because he got used to the prism that was induced by mounting outside the optical center.

Every time we set a glasses off your DNP, the client sees through a prism induced which is calculated by a rule called "Prentice" which is nothing more than the spherical diopter multiplied by decentration assembly (in cm) resulting in prism. Example +3.75 spherical mounted 5mm off the DNP (curved glasses, you know?) Results in Prism 1.88 (+3.75 cm X 0.5 = 1.88). Earlier the customer sees evil, but then he is used to and that is terrible and unacceptable.

Besides being addicted client in a prism glasses mounted with DNP out for the lens becomes thin, it will not have a good result thick if he wants to use the same frame a DNP correct. The best thing to do here is sell a suitable frame and offer a lens with an index consistent with its ametropia. Just as he got used to a DNP wrong this time too it will get used, a DNP right now. This adaptation process can last up to 10 days. After this period the client will be retrofitted.

Except prisms prescribed in revenue, I guarantee you that if you follow all the steps in this regard, the results of the thick lenses of his glasses to their customers will be the best possible technical hassle, simply choose frame centralized index consistent with prescription and proper measurement of the rim to the work order.