Anthony wrote:
I use binoculars frequently for work (wildlife surveys) and recreation (bird watching since age 15). This demands that I be able to resolve fine detail to accurately resolve multiple animals in the field of view, or to resolve fine details on an individual animal so that I can identify it to species, age, and gender.  Since I began using good pairs of roof-prism binoculars in my late 20s, I noticed that I frequently have to adjust the diopter to keep both eyes in focus even though the diopter adjustment on the binocular has not been moved. That is, if I set the diopter at zero (because my eyeglasses correct my eyesight), sometimes only one eye
will be in focus when I put the binoculars up to my eyes and sometimes both eyes will be in focus. When only one eye is in focus, I adjust the diopter (typically to beyond -2)), but after lowering the binoculars for a few minutes, then raising them to my eyes, about half the time one eye will be out of focus.  What could be the reason for this?  This is a problem whether I use my $350 Minolta binoculars or my $1,300 Zeiss binoculars.  The collimation has been checked on both binoculars and both are 7X magnification).  The problem is less noticeable with porro-prism binoculars (also 7X power), which have a greater depth of field than roof-prism binoculars.

I have been wearing eyeglasses for strong myopia and slight astigmatism since age 7.  I am now age 48.  There is a small difference in prescription between the two eyes, however, over the years my optometrists have typically given me prescriptions so that the lens for my weaker eye gives a sharp image at reading distance but not at infinity, whereas the lens for my stronger eye gives a sharp image at infinity, but not close up.  The adjustable diopter on binoculars should take care of that slight difference but the binoculars cannot be
blamed for the difference between the two eyes frequently varying from -0.25 to -3.0.  The problem with frequently needing to adjust the diopter on binoculars seems to have been present before I developed
noticeable presbyopia and at least 20 years before I began using multifocal lenses.

ANSWER

Anthony,

At age 40 you still have “some” focusing ability, and you are using this as you adjust the binoculars to clear the image. Then when you go back to use the binocular again, your focusing
will not instantly adjust.   The difference in
your two lenses in your glasses likely adds to this and I might suggest a special pair of glasses that you wear in the field that has the two eyes balanced for distance vision.  The other culprit may be the pupil distance - the separation of the lenses of the binocular.  Perhaps your Optometrist could let you know what your PD ( the distance between your
eyes) is, so that you can set that correctly on your binoculars.

I know it is frustrating when you need to quickly use your binoculars, but setting them before you leave home and using balanced glasses may help greatly.  If it is any consolation, I often have the same problem, but find it works OK when I adjust and lock them into focus for me.

Dr. Joan Hansen, Optometrist for CAO

Jane wrote:
I just got new glasses and I am seeing double when I’m looking at the side trough one lense of my new glasses. When I look at the center it’s ok, and trough the other lense it’s fine too.

My old prescription was
OD -0.75 -0.25 80
OS -0.75 -0.25 100
The new prescription is
OD -0.50 -0.50 85
OS -0.25 -0.75 100

I don’t know if you can tell by just seeing my old and new prescriptions if it’s the eye doctor who made a mistake or is the place that made my glasses that screw things up? I am seeing fine trough my old glasses by the way.

Who do I go see first about my problem, the eye doctor or the store the made my glasses?

Thank you

ANSWER

Dear Jane:
The change in prescription is slight and not likely to be causing you double vision. Check first with the store where you had the glasses made, describing the symptoms as accurately as you can. Although it happens rarely, your symptoms may be caused by a flaw in the lens that occurred during the manufacturing process.
If the lenses have been made accurately and your symptoms persist, you should check back with your optometrist. Double vision is often caused by a lack of coordination between the two eyes and it’s underlying cause needs to be determined.
Hope this helps.

Dr. Smit

Di Wood wrote:
My adult son has been diagnosed with ‘dle’ complaint whilst being tested for spectacle update. Can you please explain this ‘dle’?
Many thanks

ANSWER

Hi Di,
DLE stands for Discoid Lupus Erythematosus.  It is a skin condition that causes skin lesions and plaques and can cause scarring. This can affect the eyelids.  I am assuming that it would be affecting your son’s eyelids since it was picked up during an eye exam.  You can read more on DLE at emedicine.medscape.com/article/1065529-overview   DLE is different from systemic lupus erythematosus as it only affects the skin as opposed to the whole body.

Dr. Doman

Doug wrote:
I have temporary cloudy vision (infrequent), some floaters, scotoma (both eyes; infrequent), and tingling arms (periodically). I just had an eye exam before the cloudiness, and the doctor was not concerned with the floaters. Additionally he was not concerned about a detached retina.

Other doctors have attempted to isolate the tingling arms, with no luck. I have gone through a lot of testing on the heart, and everything is normal. They don’t think it is a stroke either.

I am currently trying to cut out caffeine, but haven’t been doing that for too long. I am starting to wonder if I need my head examined by a psychologist or with an MRI to see if it is a tumour. Any ideas on what could cause those symptoms?
Thanks in advanced!

ANSWER

Dear Doug:
You present an interesting collection of symptoms which may, or may not, be inter-related. Your floaters could be causing your episodes of temporary cloudy vision and your scotomas could be caused by a migraine phenomenon. It is outside the scope of optometry practice to offer a diagnosis for your periodic tingling arms. All of your symptoms may potentially have a central nervous system/intracranial origin. If your optometrist has concluded that your floaters are benign and that your retina is intact and healthy, I would advise you continue under the care of your family doctor to see if an underlying problem can be uncovered.

Best of luck,
Dr. Smit