RS485 Eye diagram - does it look good?
No problem going to 2f is = 50 Mbps.

The probability of error depends solely on the Voltage becoming the wrong polarity when the discriminator has computed the polarity for that bit.. 

What affects the SNR? , that determines the BER. 

The slew rate indicates a variable amplitude and thus a variable SNR declining signal level, this also means a declining BER.   

The 90% Vpp amplitude of data  occurs when the rise time Tr reduces to Tr=0.35/f.  ( by definition)

Since the bit interval, Tb= 2/f,
thus Tr=0.7Tb

Assume from the trace , Tr= 7ns   


then ideal max bit rate “may be” 0.7/7ns =100Mb/s.


However additional margin loss results from pattern dependent Inter-Symbol-Interference, ISI  perhaps from pattern dependency e.g. 011 or 0011 vs 0101 or group delay distortion or random jitter reduces the ideal margin of 100% down to some number like 30% that “may” correlate to some probability of error, or Bit Error Rate, BER = 1e-9. This depends on several other factors beyond the scope of this answer. .

The affect is not visible with a single trace capture, but is visible when displayed with trace memory overwrites.  We know the correlation between Standard Deviation of Gaussian Noise vs number of bits  so this jitter can be measured  on time interval ,TI counters and/or Phase Margin Analyzers or BER Window Margin Analyzers.

Since the visible transition is skewed or asymmetric from  ideal 50% to ~ 90% This amounts to 40% of Tr and thus degrades the Phase Margin by 40% of 7 ns or +/- 2.8ns