 |
 |
The effects of PD and Sinemet on vision seems to vary widely from person to person. I have made several unusual observations in my case. 1. After taking a Sinemet tablet, my vision worsens temporarily. My ability to read where there is less contrast between the print and the background and/or where the print is relatively small decreases. I had suspected a focus problem in which my pupil diameter widened thereby admitting more light but decreasing my depth of field. I checked this by videotaping my eyes from when a Sinemet 25/100 [not CR] was taken until I was fully "on". (I placed a reference marker strip [paper with 64 lines per inch grid] just above each eye before the test. I read aloud from a page with lines of random generated letters in decreasing point sizes. I continued reading each line aloud using a forced decision two characters beyond where I felt that I was merely guessing. After the Sinemet had me "on" I viewed the tape. My reading ability became increasingly worse after taking Sinemet, but, after a few minutes [six to ten minutes] improved, going back to the pre-medication level and better. Forced decisions did not produce any surprises and confirmed that I was just guessing beyond where I was no longer aware of being able to read. Frame by frame viewing of the tape and counting pixels on a large screen TV revealed no pupil diameter change. 2. A somewhat similar change occurs with a rapid change in atmospheric pressure. My vision becomes worse with a rapid increase in atmospheric pressure and improves with a rapid decrease in atmospheric pressure. I took a "ride" a year ago in an altitude chamber. I had taken no PD medication for more than 12 hours. I took a borrowed contrast sensitivity eye chart [a ridiculously expensive chart with letters of uniform size which decrease is print density from extreme black through grays to what I see as pure white]-with me. As I went rapidly to a simulated 3500 feet I was able to see two more letters than I had ever seen before. The extra two letters disappeared almost immediately after stopping the climbing simulation. My dexterity and smelling ability change with the change in pressure also. Any explanation? Will Johnnston A.P.D.A. DelMarVA Chapter Pres. 4049 Oakland School Road Salisbury MD 21804 USA 410-543-0110