Screening For Retinopathy Of Prematurity; Figure 139 Chiang Method: Three Images - Clarity RetCam3 User Manual

144 Chapter 11
To maximize photo-documentation of the retina, it is suggested that the following five (5)
views be captured:
1. Posterior pole
2. Temporal retinal field
3. Nasal retinal field
4. Superior retinal field
5. Inferior retinal field
When imaging Retinopathy of Prematurity (ROP), the imaging procedure as outlined
above typically provides adequate retinal coverage to assess zones 1 and 2. It is not
uncommon to miss some of zone 3 in the temporal image, but since disease isolated to
zone 3 does not result in ROP treatment, the clinical impact is negated. However, before
discharge from an ROP screening program, it is important to fully assess the entire
retina, including zone 3.

Screening for Retinopathy of Prematurity

Chiang, et. al. has reported the results of a prospective trial to measure the accuracy,
reliability, and image quality of RetCam wide-field digital images to screen for ROP.
In the study, eyes from 67 consecutive infants underwent RetCam wide-field digital retinal
imaging by trained neonatal nurses using a standard protocol of three (3) images per eye
and the 130 degree lens. The infants were 31 to 33 weeks or 35 to 37 weeks
postmenstrual age (PMA).
The protocol for this study required that a minimum of three (3) images (posterior,
temporal, and nasal photographs) be consistently captured for each of the patients. Each
image set included up to two (2) additional images from any area of the eye, if the
examining nurse believed that the images would contribute diagnostic information.
The images below were taken using a RetCam 130 Degree lens on a plastic practice eye
that has a simulated retinal detachment. The "vascular" information is not meant to
accurately represent the arcades, but provides objects to focus on. The glare seen on the
images is due to reflections from the plastic eye and is not indicative of human corneal
reflections.
Chiang's three-position imaging technique is illustrated below with the three separate 130
degree images, nasal, posterior pole, and temporal. These images show that there is
overlap (yellow dot representing the optic nerve in each view) of the digital images.

Figure 139 Chiang Method: Three Images

RetCam 3 and RetCam Shuttle User Manual
OD Nasal View
Screening for Retinopathy of Prematurity (ROP)
OD Posterior Pole View OD Temporal View
PN 18-000393 Rev. A