Friday, May 26, 2017

Can higher ADD in progressive lenses affect distance vision?

I'm on my second attempt at new progressives in as many months. I'm beginning to give up hope that I will ever see clearly again.

New glasses were required as I've become slightly over-corrected as the years passed. The old glasses were fine, except that I was having to tilt my head and look out of the lower section of the lenses to see things in the 3-6 feet range. But distance was good and reading was good. Old glasses, worn for 4 years, were this:

1.67 plastic progressives with AR coating
OD Sphere -6.00, Cylinder -.50, Axis 095, Add +2
OS Sphere -7.25, Cylinder -.50, Axis 085, Add +2

First attempt at new glasses were this:

1.67 High Definition plastic progressives with AR coating
OD Sphere -5.50, Cylinder -1.00, Axis 090, Add +2
OS Sphere -7.00, Cylinder -.75, Axis 090, Add +2

I could see clearly out of one eye at a time but together I could not achieve the "sweet spot" at the same level. In other words, when watching TV for example, if it was clear in the right lens, I had to look through a higher part of the left lens for it to be equally clear. The eye strain by the end of the day was horrible. I posted about this last month and it was suggested that the lens measurements were off and one of the lenses needed to be re-done.

So I returned the new glasses AND I went back to get a re-check on my prescription. Optometrist said "maybe the adjustment was too much for you, lets bring the right eye back a little closer to old specs".So she re-wrote the prescription to this:

1.67 High Definition plastic progressives with AR coating
OD Sphere -5.75, Cylinder -.50, Axis 090, Add +2.25
OS Sphere -7.00, Cylinder -.75, Axis 090, Add +2.25

She actually wanted to change the Add to 2.5 but I was concerned about such an increase so she put 2.25. And I'm not sure why, since she reduced the OD Sphere by only.25 diopter, that she reduced the Cyl by -.50.

So off I went again to get new glasses. The problem of lens placement seems to be corrected - i.e. Now I can see with the same level of clarity (more or less* - see comment at bottom) at the same spot on both lenses. The close-up vision is definitely better than when I was over-corrected. But the distance vision is shot. Driving is the worst. Basically anything that is not with the confines of a small room is uncomfortable. The optometrist said I was to give it 2 weeks to adjust because she says it takes the eyes longer to adjust to a reduction in prescription (apparently they have to learn to re-focus to the lesser power). But I'm on Day 4 and ready to throw in the towel. I didn't have any trouble with distance on the first attempt, so why now?

The only thing that is really different is the Add. If I understand the process, the higher Add reduces the power in the progressives more more quickly from top to bottom than if the Add was lower. Would this affect distance vision? I can't even see the close captioning on my TV clearly anymore and I need that because I'm hearing impaired.

I'm dealing with an experienced optician this time. She's tried everything she can and also double and tripled checked the measurements - centers are dead-on etc. So I'm thinking there has to be a problem with the prescription.

One last thing, I'm finding while looking at something straight on, I have to turn my head slightly to the right to get clarity in the left eye. This is only really noticeable when doing computer work and I could learn to live with it if all the above was fixed. But what would cause this? Someone previously suggested Axis but the change is only 5 degrees. Something to do with the the narrow mid-range corridor perhaps? If the latter, why only the left eye?

I'm getting desperate here! The old glasses, while the vision was not optimal, were better than either of these recent attempts but they are getting worn and eventually I'm going to have to replace them. So I need to find a solution, sooner or later.

Read more: Can higher ADD in progressive lenses affect distance vision?