September 9, 2020

Online Eyeglasses

I just bought me a new pair of eyeglasses over the counter in Tucson. It is June 2, 2009 - they cost me about $200.

Now I am investigating several online sites that offer good looking eyeglasses at attractive prices.

My prescription

To deal with them, I need my prescription, which is as follows:
		SPH	CYL	AXIS	ADD	PD
OD(right)	-225	-225	164	+200	34
OS(left)	-375	-100	178	+200	33
The PD in the above is the one-sided pupilary distance (from the center of my nose), most folks just want the sum of these (68mm), the "interpupillary distance".

I visited Dr. Tetrault again June 21, 2012 for an exam, and got the following numbers:

		SPH	CYL	AXIS	ADD	PD
OD(right)	-175	-225	170	+225	33
OS(left)	-325	-100	175	+225	33
He measured my PD as 66/63 (the 66 number is what I want to order glasses, the 63 number is for "near vision" if I understand him right.

During this visit, he mentioned that several of his clients have ordered and been happy with glasses from Zenni Optical.

My curent frames (2009) say 55 [] 19/141

Places to go

So far I am dealing with Zenni, and have been entirely satisfied. It usually takes just under a week to get a pair of glasses from them.

My son Paul has a pair of round frame Zenni frames I like: 157825

I may try "Discount Glasses" at some point in the future.

The 39 dollar site will sell a set of glasses (single vision) frames and lenses for just that price (39 dollars). A pair of glasses with progressive bifocal lenses costs 79 dollars. Buying via the link from the glassyeyes site may give a 10 or 15 percent discount (it does at the time of this writing).

In April of 2013 I finally actually ordered a set of glasses online (from Zenni Optical). I was shocked when they arrived, they are superb. A pair of progressive bifocals in a titanium frame for $72 (plus shipping). I could have picked out a less expensive frame ($10), paid the $22 for the progressive lenses, addes $5 for tint and have a $37 pair of sunglasses. And I just might.

Sunglasses

Zenni offers 3 levels of tint: 10, 50, and 80. The advice I find is that you want to select the grey (as I will) or the brown. The 10 percent tint is for "fashion", whatever that means. The 50 percent tint is the mainstream choice, but the 80 percent tint is what you want for outdoor use in bright sun, or daytime driving. Note that the G-15 "Rayban" tint is an 85 percent tint.
Conclusion: order the 80 percent tint.

Computer glasses

Reading glasses are for a 10-20 inch distance. Computer glasses are for 20-30 inches. I am now using a huge screen, and with my bifocals, I get neck strain from having to tilt my head up aggressively in order to look through the bottom of my glasses to see the top of the screen. The answer would be some single vision computer glasses.

I have some single vision "reading" glasses, but they are set up for 20 inches, which is much closer than I want to work. My usual computer screen distance is more like 30 inches, or a bit more.

The above instructions say to subtract 3mm from your normal PD to get a "near single PD". (This is consistent with my 66/63 PD values mentioned above). Then they recommend dividing the ADD value by two and adding that to SPH to order the glasses.

So here is my 2012 prescription from above.

		SPH	CYL	AXIS	ADD	PD
OD(right)	-175	-225	170	+225	33
OS(left)	-325	-100	175	+225	33
The first trick is that dividing the 225 add value by 2 yields 112.5 and the convention is that all things optical are done in steps of 25 (quarter diopter). Apparently this is not entirely true, and you can get glasses made with 1/8 diopter steps, but the general word is it doesn't matter, and go down.

Note that if we just throw the ADD value away, we get a single distance prescripton -- for distance. The ADD value adds to the SPH to give the near vision part of a bifocal. So adding less gives more of a distance prescription. Anyway, I decided to go with an ADD value of +100 and an overall PD of 63 (not 66) as mentioned above. So I ordered (on 2-2-2022) from Zenni, a pair with this prescription for $44:

		SPH	CYL	AXIS
OD(right)	-075	-225	170    (overall PD=63)
OS(left)	-225	-100	175

As a comparison, here is the prescription for some more aggressive single vision close-up glasses I had made. These work well at a distance of about 19 inches, which is too close for me at the computer:

		SPH	CYL	AXIS
OD(right)	+075	-200	164    (overall PD=65)
OS(left)	-050	-100	175
It looks like these were done with an add of +250 (my full amount)

Relensing

Zenni does not do a relensing service, but this outfit does, and seems totally cool about how they charge for it:

I never did do business with them though. Maybe I should.
Have any comments? Questions? Drop me a line!

Tom's online eyeglasses notes / tom@mmto.org