You might do some research on Iridology and the best known practitioner Bernard Jensen. He perfected the photographic techniques in the 1950s and has a few books on the subject.
Also be aware that it is bordering fully or partially on quackdom and there is not affirming studies that support it. The worst contraindication is that the believers claim the eye's iris reflexes the general state of the body and zones in the iris reflex specific organ current state and history. The only problem with that is the the iris markings are a phenotype that forums in in the embryo and does not change in later life.
If the iris was so not so individual and stable throughout life it would be useless for identification which it is in ever increasing ways such as the biometric passport control eye scans.
I would be very wary of a tutor who believes in such pseudoscience. He can't present any controlled studies that support it.
It is a fun parlor game but is not something to base a diagnosis on.
I studied enough to conclude that for the claims of success, it requires a willingly duped subject, usually with enough money to attract quacks.
Stan
St Petersburg Russia

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