Comparison of Intraocular Lens Power Calculation Methods Following Myopic Laser Refractive Surgery: New Options Using a Rotating Scheimpflug Camera

Abstract

PurposeTo evaluate and compare published methods of calculating intraocular lens (IOL) power following myopic laser refractive surgery.MethodsWe performed a retrospective review of the medical records of 69 patients (69 eyes) who had undergone myopic laser refractive surgery previously and subsequently underwent cataract surgery at Samsung Medical Center in Seoul, South Korea from January 2010 to June 2016. None of the patients had pre-refractive surgery biometric data available. The Haigis-L, Shammas, Barrett True-K (no history), Wang-Koch-Maloney, Scheimpflug total corneal refractive power (TCRP) 3 and 4 mm (SRK-T and Haigis), Scheimpflug true net power, and Scheimpflug true refractive power (TRP) 3 mm, 4 mm, and 5 mm (SRK-T and Haigis) methods were employed. IOL power required for target refraction was back-calculated using stable post-cataract surgery manifest refraction, and implanted IOL power and formula accuracy were subsequently compared among calculation methods.ResultsHaigis-L, Shammas, Barrett True-K (no history), Wang-Koch-Maloney, Scheimpflug TCRP 4 mm (Haigis), Scheimpflug true net power 4 mm (Haigis), and Scheimpflug TRP 4 mm (Haigis) formulae showed high predictability, with mean arithmetic prediction errors and standard deviations of −0.25 ± 0.59, −0.05 ± 1.19, 0.00 ± 0.88, −0.26 ± 1.17, 0.00 ± 1.09, −0.71 ± 1.20, and 0.03 ± 1.25 diopters, respectively.ConclusionsVisual outcomes within 1.0 diopter of target refraction were achieved in 85% of eyes using the calculation methods listed above. Haigis-L, Barrett True-K (no history), and Scheimpflug TCRP 4 mm (Haigis) and TRP 4 mm (Haigis) methods showed comparably low prediction errors, despite the absence of historical patient information.

Accuracy of intraocular lens power calculation formulae after laser refractive surgery in myopic eyes: a meta-analysis

“…We suggest that if the Haigis-L or Shammas-PL could be obtained, these formulae would be better than the Double-K method. Previous studies have shown that the Double-K method had good predictability of IOL power calculation when refractive historical data was known, but its accuracy decreased when historical data was unknown [17,29]. In addition, when we included Cho et al's 2018 study, I 2 was 54% and there was no significant difference between Haigis-L and Shammas-PL (P = 0.34, Fig.…”

“…Among these, three studies did not have percentage data, 16 studies included only one of the selected formulae, five studies were hyperopic laser refractive surgery or radial keratotomy surgery. After the exclusion of these studies, 16 articles were used for analysis [5,[12][13][14][15][16][17][22][23][24][25][26][27][28][29][30].…”

An Alternative Approach to Cataract Surgery Using BSS Temperature of 2.7 °C

“…Indeed, cataract surgery may present possible postoperative complications such as corneal decompensation [3], the possibility of a cornea with more swelling [4], anterior chamber reaction [5], cystoid macular edema [6], increased intraocular pressure, and, rarely, endophthalmitis [7]. An objective approach to preoperative evaluations is required to obtain the best results [8].…”

Accuracy of intraocular lens power calculation formulas after laser refractive surgery in myopic eyes: A meta-analysis

“…Before 2014, the accuracy of the Haigis-L, Shammas-PL, and W-K-M formulas was comparable, and the Double K method was slightly lower than the other three formulas [12]. After that, a large number of studies have shown that the accuracy of the Haigis-L is comparable to that of the Shammas-PL formula, while the W-K-M and Double K formulas are less accurate [17,27]. But in our analysis, there is no statistically significant difference in the percentage of refractive error percentage of the above four formulas, only the Haigis-L has better percentage of refractive predicted error within ±1.0D than the W-K-M method.…”