I am Stumped - FT-28 Question

[Rialeigh]

Pt was wearing a FT-28 and we recently did a new pair in a very similar frame. His complaint is that when wearing his FT distance and reading are great. When he looks at intermediate through either the top section or the seg everything slopes downwards to the left. He knows it will be blurry which he doesn't mind but the sloping is a problem.

Old:
+1.25 -0.50 x 096
+1.25 -0.50 x 092
Add: +2.00

Poly, non-aspheric, BC 5

New:
+1.75 -0.50 x087
+1.75 -0.25 x094
Add: +2.00

Poly non-aspheric, BC 5

Where should I start looking for the issue or any ideas? Thanks!!

[lensmanmd]

Sounds like a difference in OC heights. How’s the vertical prism? Did you adjust panto? In addition, he has changed by +.5, and what used to be comfortable at intermediate is now magnified. He may need to move closer to the screen.

[Uncle Fester]

Same amount of prism thinning?

[Randle Tibbs, ABOM]

Same amount of prism thinning?

prism thinning in FT's?

[Don Gilman]

Pt was wearing a FT-28 and we recently did a new pair in a very similar frame. His complaint is that when wearing his FT distance and reading are great. When he looks at intermediate through either the top section or the seg everything slopes downwards to the left. He knows it will be blurry which he doesn't mind but the sloping is a problem.

Old:
+1.25 -0.50 x 096
+1.25 -0.50 x 092
Add: +2.00

Poly, non-aspheric, BC 5

New:
+1.75 -0.50 x087
+1.75 -0.25 x094
Add: +2.00

Poly non-aspheric, BC 5

Where should I start looking for the issue or any ideas? Thanks!!

Probably that 2 degree axis change on the 0.25 cyl.

[AngeHamm]

Probably that 2 degree axis change on the 0.25 cyl.

[Robert Martellaro]

Pt was wearing a FT-28 and we recently did a new pair in a very similar frame. His complaint is that when wearing his FT distance and reading are great. When he looks at intermediate through either the top section or the seg everything slopes downwards to the left. He knows it will be blurry which he doesn't mind but the sloping is a problem.

Old:
+1.25 -0.50 x 096
+1.25 -0.50 x 092
Add: +2.00

Poly, non-aspheric, BC 5

New:
+1.75 -0.50 x087
+1.75 -0.25 x094
Add: +2.00

Poly non-aspheric, BC 5

Where should I start looking for the issue or any ideas? Thanks!!

Assuming healthy eyes, it's likely due to an increase in distortion (pincushion) from the power increase, possibly aggravated by a less than optimal OC position, vertex distance, center thickness, etc. Check the latter, and give the former about ten days, allowing time for the visual cortex to remap the slightly distorted image.

Hope this helps,

Robert Martellaro

[EyeManDan]

Possible 1.60

[drk]

See if it happens without the glasses on.