Archive for the ‘Prescription Lenses’ Category

Contact Lenses Power

Sunday, September 5th, 2010

Contact Lenses PowerQUESTION

I’ve been told that to calculate the right power of one’s contact lenses we must detract 0,25 diopters to the real one; mine is 1,50 and 2,00, should I choose 1,25 and 1,75 ? Other people told me that this detraction must be considered only when the graduation exceeds 3 diopters.

ANSWER

There is a mathematical formula that correlates the power of contact lenses with that of the lenses of prescription glasses. Such formula is mathematically affected by 2 factors:

  • the power of the lens on the glasses
  • the distance of the glasses lens from the corneal apex (eye)

This formula suggests that if the power of the lens doesn’t exceed 5,00 diopters, no significant variation occurs on the power of contact lenses.

Therefore, if your powers are 1,50 and 2,00, you can put contact lenses of the same powers; in case the power reduction makes your vision more comfortable, it is probable that the measurement of your graduation was not correct.

Dry Eyes

Wednesday, August 25th, 2010

Dry EyesQUESTION

After wearing my contact lenses for a while, I have got the feeling that my eyes are becoming dry.

ANSWER

When one senses the unpleasant feeling of “dry eyes”, which leads to reduce the time lenses are worn and to increase the frequency of blinking (eyelid winking), we can reasonably think about different problems:

- real “ocular dryness” (or, as to say, insufficient tears). In order to correctly evaluate this problem, it is necessary a serious medical examination;

- the internal geometry of the lens (inner shape) is not suitable to the patient’s ocular situation. In this case, a visit to the authorized optician of the contact lenses is needed;

- the lens “interefe” with the natural mechanism that controls and stimulates the frequency of the blinking (eyelid winking) and the patient must be “taught” how to restore the normal frequency of the blinking. To this aim, specific exercises exist which the optician must adjust to each single patient.

Contact Lenses Firmness

Thursday, August 5th, 2010

Contact Lenses FirmnessQUESTION

Sometimes it happens that we experience “firmness” problems with contact lenses.

In fact, the lens (either hard or soft) may “shift” from its regular position with eye-winking. Everybody asks the reason why such thing happens, but the answers are really simple.

ANSWERS

1. The lens has not been constructed with the right parameters (this is a manufacturing defect);

2. The lens has been correctly constructed, but it does not fit the eye shape (this is an “adaptation” mistake, so a technical mistake by the Optician).

There are no further reasons that may cause a problem related to the unwanted “shifting” of the lens within the eye.

Preliminary Tests For Contact Lenses

Tuesday, July 6th, 2010

Test for contact lensesQUESTION

Why my contact lenses annoy me after only 3 hours?

ANSWER

Many problems which come up while wearing contact lenses stem from poor preliminary tests. And this is also why a Patient may experience annoyance after just 3 hours of wearing contact lenses. In fact, the purpose of these preliminary tests is to find out the best technical solution.
It is true that a period of “physiological adaptation” is necessary, but it is also true that such period (at least for soft lenses) should be more or less a week. Once this period is over (unless there are evident improvements), it is good that the Optician checks the whole technical aspect of the adaptation.

Dimmed Vision

Monday, June 21st, 2010

Dimmed Vision with Daily Wear Contact LensesQUESTION

I bought daily wear contact lenses but I cannot see vey well, can anyone give me some advice?

ANSWER

There are some “strange situations” and “questions” that leave us bewildered. How is it possible that a person wears contact lenses “on their own” (that is, without the necessery technical support) and has the so-called “dimmed vision”? This can be caused by three probelms:

1. Lenses are faulty (although it is statistically infrequent that this happens for both eyes at the same time);

2. The power of the lens is not the right one to compensate the Patient’s visual defect;

3. The internal geometry prevents the lens to perfectly adapt to the Patient’s eye.

So we heartly recommend any Patient who has such problems to address their Optician in order to face and sort out these problems.

Accommodation of Contact Lenses

Tuesday, June 1st, 2010

Accommodation of contact lensesQUESTION

We are frequently asked about the correct use and accommodation of contact lenses.

ANSWER

Here below are the legal and technical procedures to follow:

1. medical check-up, which is necessary to evaluate whether the patient is suitable to the use of contact lenses;

2. technical control (on behalf of the Optician), to decide which kind of lenses to choose;

3. technical assistance to the patient to teach him how to use and maintain his own contact lenses;

4. follows-up to make sure that the use of contact lenses is not causing damages or problems to the eyes.

This is the procedue highly recommended by all professional associations of both oculists and opticians. Sometimes, to shorten times, one or two steps are skipped and that is when problems come up which are “erroneously” attributed to contact lenses.

Strabismus, Hypermetropia and Contact Lenses

Tuesday, April 27th, 2010
strabismus and contact lensesQUESTION
A patient asked if it is possible for a person suffering from strabismus and hypermetropia to wear contact lenses instead of glasses?
ANSWER
A patient suffering from hypermetropia and strabismus can wear contact lenses instead of glasses, provided that:
the contact lenses are able to meet the psychological conditions they need to adapt (this is the optician’s duty)
the correction prescribed for the glasses do not comprise the use of prisms; in which case this kind of correction cannot be carried out by contact lenses.
FINAL CONSIDERATION
In any case, the situation is quite complicate and must be dealt with by one’s optometrist and optician as well.
As far as cost is concerned, it is not particularly expensive since they are ordinary lenses.

An Year of Growth

Saturday, February 27th, 2010

Ital-lenti, the Italian company specialized in the field of ophthalmic lenses, faced a positive balance of trade in the first 9 months of 2009.
“We are really satisfied about a result which witnesses our improvement in the ophthalmic field, where we gained a new slice of the market – the company management, with the Polzotto family at the top, stated–
Two are the strategically winning choices made by the company: first of all, a policy of alliances and partnerships with well-known companies trading with frames and solar filters, above all in the sports world, which addressed to Ital-lenti as a unique and reliable supplier; then, a close and direct realtionship with opticians, thanks to dedicated marketing initiatives which allowed our company to attract new clients and put into evidence such values as precision, promptness and expertise”.

Found in Professional Optometry, September 2009

Contact Lenses to Highlight Eye Colour

Wednesday, January 13th, 2010

How to highlight eye colour
QUESTION

In which way can contact lenses interfere with the eye natural colour?

ANSWER

Just because lenses are NOT TINTED, they do not have any effect on the eye colour. Two brief notifications:

  • since contact lenses can enhance the light reflection, they may give the impression that iris is brightest.
  • if the lens edge coincides with iris edge, then it may seem that more emphasis is given to iris, but it’s just an impression.

Technological Innovation

Friday, January 8th, 2010

Essilor (Charenton, France) has investigated the existing correlations between the quality of wave fronts entering the eye and some subjective criteria of perception such as visual acuity and sensitivity to contrasts. The results of the experiments have led to the creation of a new lens concept based on the differentiated management of wave fronts according to the wearer’s needs in term of near, intermediary and far vision. In near vision, the posture adopted by the person may vary considerably according to the activity carried out, the surrounding environment, and the time of day. Moreover, posture changes from one individual to another, and so to be effective in all situations, a progressive lens has an enlarged area for near vision which is enlarged both horizontally and vertically. For Varilux physio, the use of wave fronts has made it possible to establish the optical characteristics of the lens in a very large area, both vertically and horizontally, and this is why the lenses are comfortable for near sight.
In the cases of intermediary vision, all the progressive lenses have a a residual astigmatism on both sides of the median line, a defect which is even greater the greater the prescribed addition. In the case of Varilux, the action deriving from the wave front has enabled the reduction of astigmatism and at the same time made it possible to orient the lens axis vertically, so as to perceive the visual field as larger. As far as distant vision is concerned, the defects (decrease in power and astigmatism) affect not only the quality of vision, but also all the serious defects, like coma for example. This type of defect is present in the far vision area also of progressive lenses but, thanks to the use of wave fronts, with Varilux coma control may be achieved. In this way defects are minimized for very large areas of far vision, including the mounting crossover area.

Found in Vedere International 2008