Found this on the JAA website.
<A HREF="http://www.jaa.nl/jar/jar/jar/jar.fcl.3.apx.b.c.13.htm" TARGET="_blank">http://www.jaa.nl/jar/jar/jar/jar.fcl.3.apx.b.c.13.htm</A>
Looks like -3 to -5 is OK as long as the refraction is stable.
Also notice the Date December 2000.