I wrote a matlab code for RRC filtered #QPSK modulated signal. The eye diagram is plotted using object commscope.eyediagram. The analysis of the eye object gives a vertical eye opening of 0.614. The peak value in the impulse response is given as 0.5282. The amplitudes of incoming unmodulated signal are 1 and -1.

Therefore eye opening percentage = (0.614)/(2*0.5282) = 58.12 %

Is this the correct way to calculate eye opening percentage?

For root raised cosine filtering I used the object comm.RaisedCosineTransmitFilter. I set the gain to 1.

Please attach a picture.

One of many definitions for EyeOpening is "vertical amplitude of the blank-region without any waveforms passing through the blank-region" / "vertical amplitude of the filled-region through which waveforms are passing through".

But the 2 regions "blank" & "filled" must be measured at the ideal-sampling-time-instant. The one which maximizes numerator and minimizes denominator.