Intraocular Lens Power Calculation Following Radical Keratotomy And Photorefractive Keratectomy

To report a challenging case of calculating the intraocular lens (IOL) power in a cataract patient who underwent radial keratotomy (RK) and photorefractive keratectomy (PRK), respectively.

Shenzhen Aier Eye Hospital, Shenzhen, China.

A-52-year-old female who received bilateral RK at age 23 and later enhanced by bilateral PRK at age 32. She developed severe cataract in left eye with uncorrected visual acuity of 20/600 20 years after her second refractive surgery. The IOL power was calculated using Barrett True K no history formula for RK and PRK, respectively. Target diopter was set as -2.0 D according to the patient’s habits. Recommended IOL power (+22.0D) of the formula for RK tended to myopic shift (-2.28D), while that for PRK tended to hyperopic shift (-1.09D). A compromised IOL power was selected and the IOL (ZCB00) was implanted within the capsular bag uneventfully. Refraction was -1.5D in 1 day, -2.5D in 1 week, and -2.0D in 2 months post-op follow up, and no other complications had occurred.

Barrett True K no history formula for RK was found to be more accurate in predicting IOL power in this case. Diurnal fluctuation should also be noticed when determined the accuracy. After cataract surgery, it takes at least 2 months to stabilize the refraction, and long-term observation is needed for stabilization of refraction in patients who received both RK and PRK.