Detection of retinal neovascularizations using 45 ° and 60 ° photographic fields with varying 45 ° fields simulated on a 60 ° photograph

. Purpose:  To compare the effectiveness of one‐ and two‐field 45 ° and 60 ° fundus photography for detection of retinal neovascularizations (NVEs); to compare the detection of NVEs in macular 45 ° fields centred on the fovea, between the fovea and the disc and with the nasal border along the nasal disc margin with that in standard 60 ° one‐ and two‐fields. Methods:  Two ophthalmologists assessed red‐free, black and white screening and follow‐up photographs of 58 out of a total 72 patients referred for treatment for NVEs over the 3 year period 1997–99. The assessment included analysis of the numbers, sizes and locations of NVEs identified in different photographic fields defined by a transparent grid placed over two standard 60 ° fields. Results:  Testing of 45 ° macular fields disclosed 59/81 (73%), 50/81 (62%) and 64/81 (79%), respectively, of NVEs detected in a 60 ° fovea‐centred photograph. Kappa values for detecting at least one NVE, when present, were 0.62 (95% CI 0.40–0.83), 0.38 (95% CI 0.19–0.57) and 0.83 (95% CI 0.62–0.99). The corresponding figures when compared with two‐field 60 ° photography were 59/111 (53%), 50/111 (45%) and 64/111 (58%), respectively. One macula‐centred 60 ° field disclosed 81/111 (73%) of NVEs detected by 60 ° two‐field photography with an additional optic disc‐centred field. Two‐field 45 ° photography disclosed 86/111 (77%) of NVEs detected by two‐field 60 ° photography. A total of 90% of NVEs detected in the optic disc‐centred 60 ° field only were also detected in the corresponding 45 ° field. Conclusion:  One‐field 45 ° photography cannot be recommended as a screening method for diabetic retinopathy. Two‐field 45 ° photography (macula‐centred and disc‐centred fields) disclosed 77% of NVEs detected by the corresponding two‐field 60 ° photography.