Hoffer Q Formula.

The Hoffer Q Formula — MYOPIC Keratorefractive Surgery

IOL Power Adjustment Table:

Based on the Aramberri "double K method," the numbers in each row of refractive correction represent the amount in diopters that must be ADDED TO the calculated IOL power when using the Hoffer Q Formula.

Each of the two tables listed below assume an average pre-refractive surgery corneal power of 43 D and implantation of an Alcon SA60AT intraocular lens.

MYOPIC

Axial Length (mm)

Refractive Correction (D)	20	22	24	26	28	30
2	0.4	0.3	0.2	0.2	0.1	0.0
3	0.6	0.5	0.3	0.3	0.2	0.0
4	0.8	0.6	0.5	0.3	0.2	0.0
5	1.0	0.8	0.6	0.4	0.3	0.0
6	1.2	0.9	0.7	0.5	0.4	0.1
7	1.4	1.1	0.8	0.6	0.5	0.1
8	1.6	1.2	1.0	0.7	0.6	0.2
9	1.7	1.3	1.1	0.8	0.7	0.2
10	1.9	1.5	1.2	1.0	0.7	0.3

The Hoffer Q Formula — HYPEROPIC Keratorefractive Surgery

IOL Power Adjustment Table:

Based on the Aramberri "double K method," the numbers in each row of refractive correction represent the amount in diopters that must be SUBTRACTED FROM the calculated IOL power when using the Hoffer Q Formula. If no number appears, it means that the formula is not applicable for that combination of axial length and refractive correction.

HYPEROPIC

Axial Length (mm)

Refractive Correction (D)	20	22	24	26	28	30
2	0.4	0.3	0.2	0.1	0.1	0.0
3	0.7	0.5	0.3	0.2	0.0	0.0
4	0.9	0.6	0.4	0.2	0.0	0.0
5	1.1	0.7	0.4	0.2	0.0	0.0
6	1.3	0.9	0.5	0.2	0.0	0.0

These two tables were adopted from the following:

Aramberri J. Intraocular lens power calculation after corneal refractive surgery: Double K method. J Cataract Refract Surg 2003; 29(11): 2063-2068.

Koch, D., Wang I. Calculating IOL power in eyes that have had refractive surgery. J Cataract Refract Surg 2003 29(11) 2039-2042.