Estimated pupil diameter and area (mm^2)
[diam,area] = pupilSize(lum,'model')
The mean luminance is in candelas/m2. The returned diameter and pupil
area are in mm and mm^2, respectively.
Two models implemented.
'ms' - Moon and Spencer (1944)
'dg' - DeGroot and Gebhard (1952)
Related note:
According to James E. Birren, Roland C. Casperon, & Jack Botwinick,
Age Changes in Pupil Size, J. Gerontol., #5, 1950, p.216, the following
formula can be used to predict minimum diameter as a function of age.
Age = 10:80;
diam = 9.08 - (0.082 * Age) + (0.00037 * Age.^2);
vcNewGraphWin;
plot(Age,diam); xlabel('Age (yrs)'); ylabel('Min diameter (mm)');
grid on
According to Stanley and Davies (The effect of field of view size on
steady-state pupil diameter.) the pupil size should be explained in
cd/m2 per deg of visual angle. They offer another formula
D = 7.75-5.75 [(F/846)0.41/((F/846)0.41 / 2)]
where D is the pupil diameter (mm) and F is the corneal flux density
(cdm-2 deg2). Not implemented here, but perhaps it should be.
Example:
[d,a] = humanPupilSize(100,'ms')
lumSteps = logspace(-6,6,20);
[d1,a] = humanPupilSize(lumSteps,'ms');
[d2,a] = humanPupilSize(lumSteps,'dg');
semilogx(lumSteps,d1,'r-',lumSteps,d2,'g--')
age = 30:5:70;
diam = 9.08 - (0.082 * age) + (0.00037 * age.^2);
plot(age,diam)