Phakic IOL  refers to a procedure that the artificial lens is implanted into the eye without removing the eye's natural lens. The phakic lOL is inserted through the  small incision in to the eye and placed just in front of or just behind the iris. Phakic lenses are used to correct patient refractive errors, and to reduce a person's need for glasses or contact lenses. In IOL power calculation all of the following parameters must be consider:

 •calculation formula

•calculation strategy

•calculation device

•web based calculation

I recommend that you become a member of the Zeiss cataract community, where you have very consistent information. https://cataract-community.zeiss.com/?gclid=CIyruKC1x9QCFaMW0wod61QPSg

Phakic intraocular lenses, or phakic lenses, are lenses made of plastic or silicone that are implanted into the eye permanently to reduce a person's need for glasses or contact lenses. Phakic refers to the fact that the lens is implanted into the eye without removing the eye's natural lens

These lens are used for high myopia (more than 8.00D) where LASIK and other corneal refractive procedures can not be done due to their limitations.

 For phakic IOL power calculation please follow this link

http://crstodayeurope.com/articles/2011-oct/biometry-calculations-for-phakic-iols/

A phakic intraocular lens (PIOL) is a special kind of intraocular lens that is implanted surgically into the eye to correct myopia (nearsightedness). It is called "phakic" because the eye's natural lens is left untouched. This is in contrast to intraocular lenses that are implanted into eyes after the eye's natural lens has been removed during cataract surgery.

Phakic intraocular lenses are indicated for patients with high refractive errors when the usual laser options for surgical correction (LASIK and PRK) are contraindicated

Phakic IOLs are designed to correct high myopia ranging from −5 to −20 D if the patient has enough anterior chamber depth (ACD) of at least 3 mm.[3]

Three types of phakic IOLs are available:

Angle-supported

Iris-fixated

Implantable Collamer Lens

Phakic Intraocular Lens (PIOL) is a group of lenses that are inserted into eyes of patients who have their clear natural lens. these lenses could be inserted behind the Iris in the posterior chamber (like ICL) or could be enclavated to the Iris (Iris-fixating) like Artisan and Artiflex. Normally we do this surgery in patients who have high refractive errors and are not suitable candidates for corneal-based surgeries (LASIK, LASEK, PRK,..). the reason for being a poor candidate is mainly insufficient corneal thickness for the refractive error correction, but could be corneal ectasia (Kertoconus) or...

A normal eye has almost 60 D of power as a lens complex which 2/3 of this (40 D) comes from cornea and 1/3 (20 D) is from lens. PIOLs add or subtract power to/from this lens complex in hyperopic eye (which has less than 60 D power) or mypoic eyes (which have more than 60 D) power.

Phakic IOL are basicaly similar to other Intraocular lens but these are implanted in phakic patients (Natural non cataractus lens). Usualy they are implanted in anterior or posterior chamber of eyes with very high refractive error which could not be corrected with laser surgeries. They could cause Cataract, glaucoma or increase retinal detachment risk. 

The design could be different from usual IOLs in matter of vault, haptic or pores in optic.

There are different formulas to derived IOL power like SRK II formula, where A constant, axial length and keratomteric readings are recorded to find final IOL power