Optician India

Most people who wear varifocals (progressive lenses) wear what I call general purpose or everyday varifocals. Good for distance vision, good for reading vision but not so good for intermediate vision such as when looking at a lap top or a desk mounted monitor. General purpose varifocal wearers’ grandchildren would call the intermediate vision ‘meh’ (mediocre in old language).

General purpose varifocals serve a purpose for most wearers and have done so for 65 years. However, since the widespread use of laptops and other electronic devices viewed from around 45-65 cm (18 to 26 inches) there are some people for whom general purpose varifocals simply don’t cut the mustard. The near portion of a general purpose varifocal may be of an add that does not give clear focus beyond 45 cm such as a +2.25 add for a 50 year old wearer. Of course even if the add in a general purpose varifocal does give clear focus at the required range for the electronic screen the user would have to raise their chin up to line up their eyes with the near portion of the lens and the electronic screen which might be manageable for a few seconds (rare in my experience for a screen user to view it for a few seconds) it will lead to neck ache and other postural problems when screen viewing is required for longer periods of time. People often use desk based screens for many hours per day. Furthermore, it’s not a great look when you have your chin raised up during an online team meeting.

When I exam a person who is wearing general purpose varifocals I ask them how they get on with the varifocals for screen use.Some say that they never use a screen (rare occurrence) others say they only use a phone based screen and they can hold it at an angle and distance which means they can use the near portion of their varifocals so there are no problems. Similarly, others who use a tablet screen can adjust the angle and distance to use the reading portion of their general purpose varifocal.

Yet others who use a laptop actually on their lap can use the near portion. There are some laptop users who have long arms and prefer to have the laptop at a distance which is outside the range of the near add of their general purpose varifocals. For this person there is an alternative. Those people who use screens on desks often struggle to see what is on the screen clearly with general purpose varifocals. I’ve mentioned postural issues when trying to use the near portion but there are also field of view problems when trying to use the intermediate portion. People tell me they point their nose at the screen and make small vertical and horizontal head movements hunting for the ‘sweet spot’ of the intermediate portion only to be reminded and disappointed about the poor field of view when they eventually find the sweet spot. It is my experience that intermediate portion of a general purpose varifocal is too narrow for a meaningful field of clear vision when looking at a desktop screen. For some varifocal wearers so much work is done on a desktop screen and their ability to see clearly is so limited that their work efficiency suffers.

For people with screen problems when using general purpose varifocals I offer the option of an office (also known as computer or occupational) varifocals. I use them myself when working as an optometrist. I can see the patient’s face clearly from about 50-70 cm (20-28 inches) using the top or middle part of the lens, I can see my monitor clearly at 50 cm (20 inches) using the central portion of the lens and I can see my trial lenses and clinical records using the reading portion.

Some people work at home but others work in office so I explain that with office varifocals the desktop screen will be clear, their key board and documents will be clear and people about 1.5 to 3 m (5 to 10 ft-depends on specific type of computer progressive) away will be clear but anything further than 3 m will be out of focus so if their office work involves looking at something more than 3 m away I advise that office varifocals may not be suitable for them.Some patients who attend meetings around a table Typical general purpose progressive lens Typical office/computer progressive lens tell me that everyone around the table will be with 3 m so office varifocals will be fine because they will be able to see everyone around the meeting table. Others say that the meetings are large and people will be further away than 3 m and need to be seen clearly. For those people who attend meetings with lots of people in a large room who also need to use a lap top at the meeting I suggest general purpose varifocals for the meeting and adjust the position of their laptop and to consider office varifocals when working in the office. Another benefit of office varifocals is that they can be kept on when walking around the office. For those patients who make presentations to many people in a long room them general purpose varifocals will be best for this and again office varifocals when working in
the office.

Some people will say they have a pair of glasses set for screen use by which they mean single vision intermediate lenses. I ask them how satisfied they are when reading documents with these glasses and ask if they can clearly see anyone else in the office when wearing them or if they can walk around in the office when wearing them. The responses to these questions are typically ‘unsatisfied with reading documents’, ‘can’t see anyone else clearly’ and ‘no, I can’t walk around in them’.

In the practice where I work once I’ve completed the eye examination and had a discussion about the benefits of office varifocals I hand over to my good friend and colleague Max Langfield who is a dispensing optician who has forgotten more than most dispensing opticians know. There are many different types of office varifocals and Max will ask more questions about the patient’s work environment such as how far they sit from the desktop screen, what vision they need beyond and in front of the screen. Max chose an office varifocal for me where the intermediate power sits in my primary gaze and my depth of focus is 1.3 m. It’s perfect for me. My lens also comes in other versions which give 2 m and 3 m depth of focus. Some office lenses are called progressives and others degressives. This is not the place to go into too much detail on this terminology and the optics of these lenses but what I will say is that in order for patients to be successful with office lens someone in the practice needs to be knowledgeable about the lens options available and the advantages and disadvantages of each option what information the lens manufacturers need to make the lenses.

I have many successful general purpose varifocal wearers who also use office varifocals. I help them and they help ensure the sustainability of the practice.