A comparison between one‐ and two‐field 60° fundus photography when screening for diabetic retinopathy

Abstract

ABSTRACT.Purpose: To compare the severity level of diabetic retinopathy obtained when assessed from two versus only one 60ae photographic field using colour transparencies and red-free, black-and-white photographs. To compare the areal coverage of these two photographic strategies to that of seven-field 30ae photography. Methods: Two ophthalmologists graded photographs of 74 eyes of 74 type I and II diabetes patients. Inter-method agreement was expressed in percentages and using kappa statistics and scatter-diagrams. The comparison of the approximate photographic areal coverage was done from diagrams using planimetry. Results: The severity level of retinopathy when judged from two photographic fields was more severe in 13.5% (Grader 1) and in 16.2% (Grader 2) from colour transparencies and in 13.5% (Grader 1) and in 14.9% (Grader 2) from red-free black-and-white prints, as compared to assessments from only one field. Kappa values (0.84-0.86) for inter-method agreement for five pooled retinopathy levels revealed good agreement. Neither grader missed retinopathy requiring clinical assessment or treatment (levels Ø47) when minimal retinopathy (levels 14-20) was detected using only one 60ae colour slide or red-free photograph. A second optic disc-centred field provided valuable additional information when more severe retinopathy lesions (levels Ø30) were detected in the macula-centred field. One macula-centred 60ae photograph covered 60% and two 60ae photographs 80% of the area covered by seven-field 30ae photography. Two-field 60ae photography covers areas left outside seven-field 30ae photography. Conclusion:We propose the use of one macula-centred 60ae photograph when screening for the first lesions of diabetic retinopathy. After they have been found two-field 60ae photography is recommended.

Nonmydriatic Ultra-Wide-Field Scanning Laser Ophthalmoscopy (Optomap) versus Two-Field Fundus Photography in Diabetic Retinopathy

“…The ETDRS standard is known to have good validity - given the fact that photographic grading was validated against long-term outcomes [22] - but is difficult to perform and relatively unsuitable for routine. While two 60° fundus photographs (1 macula-centered and 1 optic disc-centered) cover 80% of this area and make it unlikely that areas of neovascularization will be missed [23], most screening programs today cover significantly less retinal area. These programs still offer good screening characteristics [24], although the relatively small covered area may theoretically reduce sensitivity.…”

Nonmydriatic screening for diabetic retinopathy by ultra-widefield scanning laser ophthalmoscopy (Optomap)

“…The current best known standards for photography, the ETDRS photographs, consist of seven single (stereoscopic) 30°images taken after pupil dilation; they cover 75-65°of the central retina. While two 60°fundus photographs, one macula-centered and one optic disc-centered, cover 80% of this area imaged and make it unlikely that areas of neovascularisation will be missed [20], most screening programs cover significantly less retina area. Although these programs still offer good screening characteristics [19], this fact might reduce their sensitivity.…”

Tele-Screening for Diabetic Retinopathy With the Retinal Thickness Analyzer

“…A single 60°nonstereoscopic fundus picture covering 60% of this area was found not to be sensitive enough for screening purposes (31). Two 60°fundus photographs, one macula and the other optic disc centered, cover 80% of the area imaged by EDTRS photographs and even add some areas, making it unlikely to miss areas of neovascularization (32). In a primary care setting, two 45°fundus photographs, one centered on macula and one centered on the optic disc, offer good screening characteristics (16).…”