Comparison of the Nidek EAS 1000 System and the Topcon SL-45 in Clinical Application

Abstract

Some years ago, Nidek developed a new imaging system for the anterior eye segment, which offers the possibility of recording Scheimpflug and retroillumination images. The system consists of 2 different technical units, a camera unit for image recording and a computer unit for storage, system operation and image analysis. To evaluate the clinical use of the system and its reproducibility, a study with 31 volunteers/patients was performed that were photographed with the Nidek EAS 1000 at the meridians 0°, 45° and 180°. Two examinations with a 1-week interval were performed. In addition, a direct comparison of the EAS 1000 with the Topcon SL-45 was carried out with 32 volunteers that were photographed at 0° and 45°; a retroillumination photo was additionally recorded. The video images were evaluated with the computer software, the SL-45 negatives were standardly measured with a Joyce-Loebl densitometer. The handling of the EAS 1000 in clinical use was found to be easy and comfortable for the patient, as the alignment is done with infrared light. Difficulties occur only with the retroillumination photography in that the infrared light for imaging may outshine the red fixation light during exposure. However, shadowing problems due to the eyelashes occur in oblique slit positions, especially in those patients with a pronounced front head. In studying the reproducibility, the mean values of the individual coefficients of variation for light scattering (density) were in a range between 3.6 and 5.06%, but more than 35% of the single values show a variation coefficient above 5% (maximum 20.3%). In a direct comparison of the 2 systems, the SL-45 still has its advantages, but the EAS 1000 with its video imaging technique can become the system of the future, after several improvements in hard- and software have been made.

External factors in the development of cataract

“…Implementing Scheimpflug and retroillumination digital photography with computerised analysis of lens opacities has allowed progression of cataract to be measured with great precision. [71][72][73][74][75][76][77][78][79][80][81][82][83][84][85][86][87][88] This method, cost effective for the large epidemiological studies, 89 is probably the best technique for recording cataract changes.…”

Central corneal thickness measurements using Orbscan II, Visante, ultrasound, and Pentacam pachymetry after laser in situ keratomileusis for myopia

“…It has been used in the assessment of cataract [6][7][8] and for measuring corneal curvature and thickness. 9 It is a rotating camera that offers a noninvasive assessment of the anterior segment of the eye.…”

Image Analysis of Implanted Rigid and Foldable Intraocular Lenses in Human Eyes Using Scheimpflug Photography

“…We used the Scheimpflug system EAS-1000 of Nidek Co. with digital image analysis. The same system allows to take additional retroillumination photographs and their analysis [8][9][10]. We could prove in a former exploration the good quality and reliability of biometric data in pseudophacic eyes obtained by this system [11,12].…”