Yes, we only use thin lens approximation formulas, even when working
with very strong lenses. I'm not even sure they teach thick lens
formulas for optometry students any more...

w.stacy, o.d.

Spectacle prescriptions for aphakic glasses usually had one extra parameter
from the thick-lens formula - not thickness but "vertex distance", the
distance from the corneal pole to the posterior spectacle surface in primary
gaze.

With +16 lenses, like magnifying glasses, vertex distance could produce huge
differences in effective power. Vertex distances were specified on the
prescription so if glasses fit differently, the power could be adjusted.

-MT

The thick lens formula is an issue that belonged to us old time lab rats.
Then came the Commodore 64 and the Intel 8088 based IBMs. The formula is a
manufacturing issue, not a refracting issue. Don't make an optometrist dust
off their old college optical physics book for something that has no
relevance to them. It's now handled ( in the few instances it's needed) by
the computer that tells the curve generator (grinding machine) how to rough
grind the blank to produce the specified Rx provided by the optometrist.

The exam and determining the Rx has nothing to do with that formula. That is
strictly a manufacturing formula.

Carl

I was taught aome thick lens formulas as background for opththalmic optics,
but most optics problems were done with thin lens formula -- I'm old enough
to have used a slide rule for those problems and thick lens formulas would
have been a calculation nightmare.

In practice, we seldom have to use any formulas.  Refraction is done with
trial lens or a phoropter so no calculations are needed.  We are aware of
the effects of thick lenses in terms of aberrations, but knowing they exist
does not require use of the formulas.

Lens designers at the optical lens companies would use thick lens formulas
for lens design, but optometrists do not design lenses.

Dr Judy