Real-life comparison of the viewing angle and the image quality of two commonly used viewing systems for vitreoretinal surgery

Abstract

Background/aim: To compare the clinical use, image quality and viewing angle of a commonly used contact wide angle viewing (WAV) system (Advanced Visual Instruments (AVI) Panoramic Imaging Systems, NY, USA) with a commonly used noncontact WAV system (Leica RUV800, Leica Microsystems, Switzerland).

Materials and methods: Images of 42 consecutively operated eyes were obtained with both systems at the same surgical stages and were compared for image quality using the Imatest Master 4.5.13 (Imatest LLC, Boulder, USA) software. The viewing angles of the images were calculated using the optic disc sizes measured from the OCT and infrared fundus images. The 68-degree AVI lens was compared with the 90-dioptre (D) Leica RUV800 lens, while the 130-degree AVI lens was compared with the 132-D Leica RUV800 lens. The surgical assistants were asked to grade the difficulty of holding the lens in place from 1 to 10, 1 being the easiest and 10 being the most difficult.

Results: The contact system provided wider viewing angles with higher quality compared to the noncontact system both under fluid and air media. The difference was clinically significant in eyes with impaired corneal clarity, very high myopia, or small pupil. The difficulty of holding the lens in place ranged from 4 to 7, and decreased gradually with practice.

Conclusions: Both WAV systems provided high image quality and adequate viewing angles in most cases. However, the contact system appeared to provide a superior image quality and/or a wider viewing angle in more challenging situations. The difficulty of holding the contact lens in place was found to be moderate.

Keywords: Image quality; viewing angle; vitreoretinal surgery; wide angle viewing system.

Figure 1

A wider viewing angle and better visualization of the surgical field are noted with the AVI 130-degree lens (A, 110 degrees) compared to the Leica RUV800 XL lens (B, 90 degrees) under fluid in the images from the same step of surgery. Similarly, a wider angle and better visualization of retina with the AVI 130-degree lens (C, 165 degrees) compared to the Leica RUV800 XL lens (D, 110 degrees) are noted under air in images from a different surgery.

Figure 2

The AVI 68-degree lens (A, 70 degrees) provided a wider viewing angle and better visualization under fluid compared to the Leica RUV800 90 D lens (B, 50 degrees) in the images taken at the same step of surgery. Similarly, a wider angle and better visualization of retina with the AVI 68-degree lens (C, 110 degrees) compared to the Leica RUV800 XL lens (D, 75 degrees) are noted under air in images from the same surgery.

Figure 3

In an eye with a pupil size of 4.5 mm under fluid medium the AVI 130-degree lens provided a viewing angle of 100 degrees (A), which made the temporally located 2 peripheral tears visible (B). With the RUV800 XL lens the viewing angle was 80 degrees, and the tears on the temporal side were not visible under fluid medium without scleral indentation (C). In another eye with traumatic corneal edema (D) and retinal detachment, under fluid medium the AVI 130-degree lens (E) provided a wider viewing angle and a much clear and detailed visualization of the fundus than the RUV800 XL lens (F). In another eye with a dropped nucleus and cataract surgery induced corneal edema (G), under fluid medium the AVI 68-degree lens (H) provided a wider viewing angle and a much clear and detailed visualization of the fundus than the RUV800 90 D lens (I).