Ocular biometric measurements in cataract surgery candidates in Portugal

Objective Describe the ocular biometric parameters and their associations in a population of cataract surgery candidates. Methods A cross-sectional study of 13,012 eyes of 6,506 patients was performed. Biometric parameters of the eyes were measured by optical low-coherence reflectometry. The axial length (AL), mean keratometry (K) and astigmatism, anterior chamber depth (ACD) (epithelium to lens), lens thickness (LT), and Corneal Diameter (CD) were evaluated. Results The mean age was 69 +/- 10 years (44-99 years). Mean AL, Km, and ACD were 23.87 +/- 1.55 mm (19.8-31.92 mm), 43.91 +/- 1.71 D (40.61-51.14 D), and 3.25 +/- 0.44 mm (2.04-5.28 mm), respectively. The mean LT was 4.32 +/- 0.49 mm (2.73-5.77 mm) and the mean CD was 12.02 +/- 0.46 mm (10.50-14.15 mm). The mean corneal astigmatism was 1.08 +/- 0.84 D (0.00-7.58 D) and 43.5% of eyes had astigmatism >= 1.00 D. Male patients had longer AL and ACDs (p <.001) and flatter corneas (p <.001). In regression models considering age, gender, Km, ACD, LT, and CD, a longer AL was associated with being male and having higher ACD, LT and CD. Conclusions These data represent normative biometric values for the Portuguese population. The greatest predictor of ocular biometrics was gender. There was no significant correlation between age and AL, ACD, or Km. These results may be relevant in the evaluation of refractive error and in the calculation of intraocular lens power.