Ocular biometric measurements in cataract surgery candidates in Portugal

Abstract

ObjectiveDescribe the ocular biometric parameters and their associations in a population of cataract surgery candidates.MethodsA 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.ResultsThe 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.ConclusionsThese 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.

Ocular biometric analysis of cataract surgery candidates, referred from community outreach camps, organized at rural areas of central India

“…Similar to the present study Ferreira et al reported there was the positive association between AL, K and ACD (p>0.05) and CD, and the negative association between AL and LT. 12 These results are in concurrence with those presented in the literature except for K, whose association with AL is inverse in most series, showing emmetropic association between corneal curvature and AL. [26][27][28] Although there may be population differences and the correlation with refractive error has not been addressed in this study, the different published studies in the literature reported keratometry assessed with automatic, manual, or IOL master keratometry, and these values cannot be compared directly with ours because of different methods of measurement and refractive indices used.…”

“…13 Age at the time of cataract operation varies from country to country example, in southern Chinese11 mean age was 70.4±10.5 years about 7 years older than our patients. The mean age 64.04±10.81 years was reported Natung et al 12 This implies that the cataract problem increases with age and it mainly occurs in 7th decade of life.…”

“…Our findings were in accordance with Shoaib et al, who reported that in their study male were 412 (54.79%) and females were 340 (45.2%). 13 There were 334 males and 307 females in the study performed by Natung et al 12 In a study by Nigam 12 Natung et al reported that the mean AL in males (23.58±0.99 mm) was longer than the females (23.07±1.19 mm) and was statistically significant (p=0.001). 15 Fifty-seven participants (8.9%) had AL <22 mm, 521 (81.3%) had between 22 and 24.5 mm, 48 (7.5%) had between 24.51 and 26 mm, and 15 (2.3%) had >26 mm.…”

“…11 Although there are several studies that explain these mean parameters in European-Caucasian population, but there has been very little attention to the studies carried out in Asian, Black and Hispanic populations. 12 There has not before been a large study of biometric values for rural Indian population. The objective of our study is to describe ocular biometric parameters and their correlations in the population of the cataract surgery candidates in rural central India.…”

Relationship between effective lens position and axial position of a thick intraocular lens

“…It is insufficient to place a thick IOL with its principal plane at the ELP for ray-tracing simulations of the pseudophakic eye with a thick IOL. The difference between the ALP and ELP (IOL with P = 20 D) varies by less than 0.03 mm as a function of DC for the normal range of DC (between 40 D and 51 D [ 14 ]). The corneal power has larger impact for thick low powered IOLs.…”