First Differentials with high myopia/presbyopia/cataracts

Hi,

I am trying to work out my first differentials, but there are a couple of complicating factors, namely, presbyopia and cataract, plus the added inconvenience of not being able to get out to try plus lenses in a store due to the current stay-at-home restrictions here.

My last optometrist script was in November 2019:
R: -11.75 (-1.5 cyl)
L: -12.00 (-0.50 cyl)

These are my current glasses. I was also suggested to get +0.75 reading glasses which I didn’t get.

December 2020: The optometrist said I had a cataract in the right eye and because I couldn’t see the Snellen chart clearly with any of the lenses she used, she didn’t give me a script. I was told to go and get cataract surgery in the right eye and then come back. So now I have an ophthalmologist appointment in a week to discuss surgery.

Cm average is L: 11 and R: 8

Snellen Chart (with current glasses at 3m) - I can’t see anything clearly with the right eye. Left eye: 20/15.

Close up habits: A couple of hours a day at an ergonomic distance of 50cm, if that, mainly researching and watching videos for Endmyopia.

Question 1: In the absence of a current prescription, does it sound sensible to calculate my diopters from my cm readings and start with a 0.5 diopter reduction in each eye?

Question 2: Does anyone have any recommendations for a friendly optometrist in London or surrounds. It would really help us out while we can’t get out to try plus lenses (my 13-year-old son is doing this with me).

Thank you so much.

Hi, sounds like a complicated situation , sorry to read that :frowning:

one tip though: check your axis from your last prescription for that cyl - and try measuring cm to blur separately for strong axis and weak axis (by looking at lines at those angles respectively and seeing where you first see a hint of blur on the edge of a line)- the cm to blur on best axis gives your approximation of SPH (contact lens prescription) and on worst axis gives your SPH+CYL contact lens prescription approximation (so then it is easy to calculate cyl needs as SPH+CYL estimation minus SPH estimation.

So once you are confident you have a reliable cm to blur reading then you can use your vertex distance to find your estimated current glasses prescription
see

and

for you with that high prescription vertex distance will make a big difference between contact lens and glasses prescription

following the above you will have a reasonably good estimation of needed differentials (cataract effect not considered )

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Thank you so much for that.