Comparative Analysis Of Refractive Predictability In Dense Cataracts: Impact Of Axial Length Measurement Method In Brown And Mature Cases

To compare refractive predictability after phacoemulsification in dense cataracts by analyzing brown and mature cases, and to determine whether ultrasound-based axial length (AL) measurement—required when optical biometry fails in mature cataracts—affects the accuracy of SRK/T intraocular lens (IOL) power calculation.

Beyoglu Eye Training and Research Hospital, Cataract and Refractive Surgery Department, Istanbul, Türkiye

A total of 178 eyes with dense cataracts undergoing phacoemulsification between January and December 2024 were retrospectively analyzed. The cases were divided into brown (n=85) and mature (n=93) cataract groups. Keratometry (K1–K2) and axial length (AL) measurements were obtained using the Nidek AL-Scan optical biometer. In mature cataracts , AL was measured by A-scan ultrasound and included in the calculation. In all eyes, intraocular lens (IOL) power was calculated using the SRK/T formula. Preoperative biometric parameters, target refraction, postoperative refraction, refractive error, best-corrected visual acuity (BCVA), and systemic or ocular risk factors were recorded and compared between the two groups.

Of the 178 eyes included, 85 had brown and 93 had mature cataracts, with comparable systemic and ocular risk factors as well as intraoperative complication rates (16.1% vs. 12.9%). Keratometric values were comparable, while AL was longer in the brown group (23.75 ± 1.68 vs. 23.24 ± 0.89 mm; p = 0.050). In brown cataracts, the difference between target and achieved refraction was not significant (p = 0.113), whereas in mature cataracts, achieved refraction was significantly more myopic than the target (p = 0.043). The mean refractive error was higher in the mature group (−0.26 ± 1.08 D vs. +0.17 ± 0.84 D; p = 0.014). Achieved refraction in mature cataracts was more myopic than in brown cataracts (−0.63 ± 0.99 vs. −0.26 ± 0.78 D; p = 0.013).

Despite comparable surgical risk factors and complication rates between groups, mature cataracts demonstrated a greater tendency toward postoperative myopic shift compared with brown cataracts. This difference appears to be associated with ultrasound-based axial length measurement. Although the SRK/T formula provided clinically acceptable refractive outcomes, anticipating this myopic tendency and targeting slight hyperopia may further improve refractive predictability in mature cataracts.