Abstract
Purpose :
In cases of dense cataract, such as mature cataracts, it can be difficult to measure axial length with an optical biometer due to scattering of light and attenuation of the light intensity reaching the retina.
The purpose of this study is to evaluate the accuracy and effectiveness of the enhanced retina visualization (ERV) mode in cases where dense cataracts complicate axial length measurement by standard mode of swept-source optical coherence tomography (SS-OCT) biometer.
Methods :
The ERV mode is a function unique to the SS-OCT biometer ARGOS (Movu /Santec, Komaki Japan ; ARG). The sensitivity at the retinal segment using this mode is 10 times higher than that with the standard measurement mode.
We performed SS-OCT biometer using both the IOLMaster 700 (Carl Zeiss Meditec AG, Jena Germany; IM7) and ARG in 150 eyes in 110 patients with grade 4 or greater cataract density, categorized by the Emery-Little classification. The mean age was 73.1±14.1 years.
In 36 eyes, axial length could not be measured using both the IM7 and the ARG in standard mode. We performed using the ERV mode in these eyes (study group). In 17 eyes (ERV subgroup) in which axial length could be measured with ARG before and after surgery, the difference in axial length before and after surgery was compared to evaluate the accuracy of the ERV mode. The Mann-Whitney U test was applied for statistical analyses, with a P value less than 0.05 considered statistically significant.
Results :
In 23 of the 36 eyes (63.9%), we successfully measured axial length using the ERV mode. Axial length in the 17 eyes that could be measured both pre- and postoperatively (ERV subgroup) was 25.14 ± 2.14 mm and 25.18 ± 2.30 mm, respectively. The correlation coefficient (Spearman's rho) was 0.993, using a Bland-Altman plot, bias was 0.14 ± 0.41 mm, and the 95% limits of agreement were from -0.94 to 0.66 mm. There was no statistically significant difference between pre- and postoperative axial length measurements in the ERV subgroup (P =0.5554). However, two out of the 17 eyes were outliers, with axial length differences before and after operation of 0.88 mm and 1.46 mm.
Conclusions :
In patients with dense cataracts that prevented measurement of axial length using standard mode SS-OCT biometer, the ERV mode showed promising findings and it is a viable means same as ultrasound A scan.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.