Intrasession Repeatability of Biometric Measurements Obtained with a Low-Coherence Interferometry System in Pseudophakic Eyes

Abstract

Purpose: To evaluate the intrasession repeatability of the biometric measurements obtained with a low coherence reflectometry optical biometer in pseudophakic eyes implanted with two different types of intraocular lens (IOL). Methods: Prospective, single-center, comparative study including 69 eyes of 69 patients with ages ranging from 51 to 92 years. Previous uncomplicated cataract surgery had been performed in all patients 1 to 2 months before measurements, with implantation of the Acrysof SN60WF IOL in 35 eyes (35 patients, group 1) and the IOL Akreos MI60 in 34 eyes (34 patients, group 2). A complete postoperative ophthalmological examination was performed including three consecutive measurements with the "Aladdin" system from (Topcon, Japan). Intrasession repeatability of axial length (AXL), anterior chamber depth (ACD) and IOL thickness (IOLT) was assessed with the within-subject standard deviation (S w), intraobserver precision (1.96 x S w), coefficient of variation (CV) and intraclass correlation coefficient (ICC). Results: The S w for AXL measurements was 0.03 and 0.05 mm in groups 1 and 2, respectively, with ICC of 1.000 and 0.999 (CV: 0.14 and 0.22%) (p≤0.031). Concerning pseudophakic ACD, the S w was 0.03 and 0.09 mm in groups 1 and 2, respectively, with ICC of 0.992 and 0.956 (CV: 0.55 and 1.75%) (p≤0.021). The variability of IOLT measurements was high in both groups, with S w of 0.12 and 0.29 mm for groups 1 and 2 (p=0.008), respectively, and ICC of 0.065 and 0.770 (CV: 20.84 and 62.39%). Conclusions: The optical biometer "Aladdin" (Topcon, Japan) provides consistent measurements of AXL and ACD in pseudophakic eyes. However, there is a limitation in the consistency of IOLT measurements that should be investigated further.

Evaluation of 6 biometers based on different optical technologies

“… 9 Ruiz-Belda et al evaluated 53 healthy eyes and recorded a mean S w of 0.26 and 0.24 D for K1 and K2, respectively; recently, Fukumitsu et al, for 69 cataract eyes, reported S w values of 0.03 to 0.05 mm and 0.03 to 0.09 for AL and ACD, respectively. 10 , 11 …”

Relationship between Medium-Term Changes in Intraocular Lens Position and Refraction after Cataract Surgery with Two Different Models of Monofocal Lenses

“…In the current study, a low-coherence interferometry biometer was used to measure the ACD postoperatively, which has been shown to provide consistent measurements of ACD and axial length in pseudophakic eyes [21]. The ACD measurement was used to determine the IOL real position, which is not ELP, as previously mentioned.…”

“…Visual acuity, subjective and objective refraction, anterior and posterior segment findings on slit lamp examination, and pseudophakic biometric data were obtained in all patients at 1 and 6 months after surgery. Only pseudophakic AXL and ACD measurements were collected during the follow-up considering that they have been to be consistent enough for research purposes [21]. It should be considered that an extremely poor consistency of the pseudophakic lens thickness measurements provided by the biometry device used in the current study was previously documented [21].…”

“…Only pseudophakic AXL and ACD measurements were collected during the follow-up considering that they have been to be consistent enough for research purposes [21]. It should be considered that an extremely poor consistency of the pseudophakic lens thickness measurements provided by the biometry device used in the current study was previously documented [21]. A single experienced examiner (HFM) performed all biometric measurements of the study during the morning period, between 8:30 a.m. and 3:00 p.m.…”

“…The purpose of the current study was to characterize the variations of ELP and IOL positions measured with a biometry device, validated for this purpose [21] during a 6-month follow-up of the eyes of patients who underwent uneventful cataract surgery, and who were implanted with two different types of monofocal IOLs. We also investigated the relationship with residual refraction and if it could be accurately predicted from preoperative data.…”