Addition of Mid-peripheral Fields to 2-Field Disc and Macula Handheld Retinal Images Improves Agreement with Early Treatment Diabetic Retinopathy Study (ETDRS) 7-Standard Field Photography

Abstract

Purpose : To determine benefit of 5-field (5F) vs 2-field (2F) mydriatic handheld retinal imaging for assessment of diabetic retinopathy (DR) as compared with standard ETDRS 7-field 30⁰ fundus photographs (ETDRS photos).

Methods : Following standard imaging protocol, 5 fields (macula, disc, superior, inferior and nasal) were acquired using 2 handheld retinal cameras [Aurora (AU), Smartscope (SS)] and ETDRS photos following pupil dilation (Figure 1). Images were evaluated at a centralized reading center independently by masked graders (International DR Classification). Simple (K) and weighted (K_W) kappa statistics assessed agreement for DR. Sensitivity and specificity for any DR, referable DR [(refDR) moderate nonproliferative DR (NPDR) or worse, any DME or ungradable images] and vision threatening DR [(vtDR) severe NPDR or worse, clinically significant DME (CSME) or ungradable images] were calculated.

Results : Images from 177 eyes of 92 patients with diabetes were evaluated. By ETDRS photos: No DR 40.1% eyes, mild NPDR 19.2%, moderate 14.7%, severe 10.2%, proliferative DR 15.8%; No DME 72.9% eyes, DME 6.8%, CSME 17.0%; ungradable 3.4%. Ungradable rate for DR: AU, 2F:1.1%, 5F:0%; SS, 2F:5.0%, 5F: 4.5%; and DME: AU:10.2%, SS:13.0%. DR agreement with ETDRS photos are shown in table 1. 5F imaging increased exact agreement w/ ETDRS photos by 32.5% AU and 19.8% SS and w/in 1-step by 8.9% AU, 6.6% SS. 5F imaging increased k agreement w/ ETDRS photos for DR from moderate to substantial for both AU and SS. Reliability indices are shown in table 1. 5F imaging increased sensitivity for any DR, refDR and vtDR on both AU (0.76 to 0.97, 0.78 to 0.88, 0.83 to 0.86) and SS (0.79 to 0.82, 0.79 to 0.87, 0.83 to 0.89).

Conclusions : The peripheral fields obtained using a 5F protocol with 2 handheld retinal cameras substantially increased agreement with ETDRS-determined DR as compared with only posterior 2F imaging. Sensitivity increased while maintaining specificity for identifying refDR and vtDR. The observed DR grading agreement between 5F handheld imaging and ETDRS photos suggests that handheld retinal imaging performed in this manner may be accurate enough for DR screening programs, where their size, cost and ease of use attributes would allow them to be widely deployed in community-based DR screening programs.

This is a 2021 ARVO Annual Meeting abstract.

 

Figure 1

 

Table 1