|Year : 2017 | Volume
| Issue : 2 | Page : 108-111
Standard versus widefield angiography in detecting new vessels in proliferative diabetic retinopathy
S Sindhu, Shruti Chandra, Mahesh Gopalakrishnan
Vitreo-Retinal Services, Giridhar Eye Institute, Kochi, Kerala, India
|Date of Web Publication||10-Aug-2017|
Giridhar Eye Institute, Ponneth Temple Road, Kadavanthra, Kochi - 682 020, Kerala
Source of Support: None, Conflict of Interest: None
Purpose: The purpose of this study was to find out the accuracy of detecting new vessels (NVE) using standard field and widefield (SF and WF) angiographic imaging modality in eyes with proliferative diabetic retinopathy (PDR).
Methods: This is a retrospective, cross-sectional study of 88 patients who underwent fundus fluorescein angiography (FFA) for suspected PDR from March 2015 to August 2015. Angiography was performed on the SPECTRALIS (Heidelberg, Germany) using SF 55° lens at primary, up, down, right, and left gaze and Staurenghi WF 102° lens in primary gaze. NVE were diagnosed by standard definition on FFA and a number of NVE were counted. Comparison of NVE detected on WF versus SF in primary gaze and WF versus SF in peripheral gaze was made. Fisher's exact t-test was used for statistical analysis.
Results: The mean age of the patients was 56.87 ± 12.42 years. PDR was bilateral in 73 eyes and unilateral in 15 eyes. On comparing WF versus SF in primary gaze, 117 and 99 eyes were correctly detected as having NVE, respectively. On comparison of WF with SF in peripheral gaze, NVE picked up was 117 and 114 eyes, respectively. The missed NVE count in both comparisons was found to be statistically significant (P < 0.02). The sensitivity of SF in primary gaze was calculated to be 84.6%, whereas in peripheral gazes, it improved to 97.4%.
Conclusion: As evident by our study results, SF images in primary as well as all peripheral gazes tend to miss out on NVE, thereby incorrectly diagnosing PDR eyes as non-PDR, which were picked up on WF as having NVE. Hence, we propose that WF angiography can be considered as gold standard for accurately diagnosing the presence of NVE in eyes with PDR.
Keywords: Fundus fluorescein angiography, nonproliferative diabetic retinopathy, NVE, proliferative diabetic retinopathy
|How to cite this article:|
Sindhu S, Chandra S, Gopalakrishnan M. Standard versus widefield angiography in detecting new vessels in proliferative diabetic retinopathy. Kerala J Ophthalmol 2017;29:108-11
|How to cite this URL:|
Sindhu S, Chandra S, Gopalakrishnan M. Standard versus widefield angiography in detecting new vessels in proliferative diabetic retinopathy. Kerala J Ophthalmol [serial online] 2017 [cited 2021 May 7];29:108-11. Available from: http://www.kjophthal.com/text.asp?2017/29/2/108/212751
| Introduction|| |
According to the WHO, 31.7 million people were affected by diabetes mellitus in India in the year 2000. This figure is estimated to increase to 79.4 million by 2030, the largest number in any nation in the world. As per the All India Ophthalmological Society survey done in 2014, the prevalence of diabetic retinopathy (DR) in India is estimated to be 21.7%. As per reports data by Wong et al., the global prevalence of DR is 93 million, of which 17 million with proliferative DR (PDR).
Aim of the study
The purpose of the study was to find out the accuracy of detecting new vessels (NVE) using standard field and widefield (SF and WF) angiographic imaging modality in eyes with PDR.
| Methods|| |
This is a retrospective, cross-sectional study of 88 patients who underwent fundus fluorescein angiography (FFA) for suspected PDR from March 2015 to August 2015. Angiography was performed on the SPECTRALIS (Heidelberg, Germany) using SF 55° lens at primary, up, down, right, and left gaze and Staurenghi WF 102° lens in primary gaze. NVE were diagnosed by standard definition on FFA and a number of NVE were counted.
Comparison of NVE detected on WF versus SF in primary gaze and WF versus SF in peripheral gaze was made.
The number of NV detected in each quadrant were also analyzed.
Eyes with significant media haze due to cataract precluding the NVE visualization, eyes with vitreous hemorrhage, tractional retinal detachment, and history of previous laser treatment were excluded from the study [Figure 1],[Figure 2],[Figure 3].
|Figure 1: NVE (upper 4 images) and standard field and widefield lens with corresponding fundus fluorescein angiography images (bottom images)|
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|Figure 2: Fundus fluorescein angiography image taken with standard lens (left) and widefield lens (right)-arrow showing NVE detected only in widefield image|
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|Figure 3: Fundus fluorescein angiography image of standard lens in straight and all gazes and arrow showing widefield image in straight gaze with NVE detected|
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NVE counting was done after marking 2 lines centered on fovea, which divided the FFA image into four quadrants – superior, inferior, nasal, and temporal. Counting of NVE in SF FFA images was done taking into consideration of vascular landmarks so as to avoid any errors in counting NVE [Figure 4].
|Figure 4: Counting of NVE in standard field straight and peripheral gazes (left images) and widefield straight gaze (bottom right with arrow)|
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| Results|| |
The mean age of the patients was 56.87 ± 12.42 years with 54 males and 34 females. PDR was bilateral in 73 eyes and unilateral in 15 eyes. A total of 117 eyes were included in the study [Table 1].
On comparing WF versus SF in primary gaze, 117 and 99 eyes were correctly detected as having NVE, respectively. On comparison of WF with SF in peripheral gaze, NVE picked up was 117 and 114 eyes, respectively [Figure 5].
|Figure 5: Pie chart showing NVE picked up with standard and widefield lens|
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Of 117 eyes interpreted as PDR with WF FFA image, a diagnosis of PDR was wrongly made as non-PDR (NPDR) in 18 eyes with SF lens FFA images in straight gaze alone and 3 eyes with SF lens images including the peripheral gazes. The missed NV was detected in nasal quadrant in all the 3 eyes. In 2 eyes, the NVE was in upper nasal quadrant and 1 eye in lower nasal quadrant [Figure 6].
The missed NVE count in both comparisons was found to be statistically significant (P < 0.02). The sensitivity of SF in primary gaze was calculated to be 84.6%, whereas in peripheral gazes, it improved to 97.4%.
The number of NVE in all four quadrants detected with SF and WF FFA images were compared. The NVE count was maximum in nasal quadrant and minimum in temporal quadrant in both images. However, on analyzing number of NVE detected quadrant wise by SF and WF images, the difference was not statistically significant (P = 0.6432) [Table 2].
| Discussion|| |
Visualization of the peripheral retina using ultra-WF imaging has led to new era in the assessment of DR. Price et al., compared the Optos ultra widefield scanning laser ophthalmoscope images and early treatment DR study (ETDRS) seven-standard field view in their ability to grade diabetic retinopathy severity. They concluded the Optos ultra widefield scanning laser ophthalmoscope assigned 19% of the images with higher diabetic retinopathy severity. Similarly, Wessel et al. demonstrated retinal pathology (including nonperfusion and neovascularization) not evident in a 7-SF in 10% of eyes. Talks et al. showed that Optomap ultra-WF images detected approximately 30% more peripheral neovascularization than standard two-field imaging. Silva et al. reported that DR severity differs in 20% of eyes when comparing ultra-WF imaging and ETDRS 7-SF images. Similarly, our study which compared imaging using two different lens showed difference in diagnosis of PDR with 2 imaging modalities. There is no similar study like ours comparing detection of NVE using Staurenghi WF lens and SF lens. Our study showed that among the 117 eyes included, NVE were detected in 18 eyes exclusively by WF lens when SF lens images only in straight gaze were considered. Hence, 15.38% (18/117) eyes had NVE that could not be detected with SF lens in straight gaze. Hence, when only SF images in straight gaze were taken, there is rough estimation of missing one NVE case in every 15 PDR patients and they will be wrongly diagnosed as NPDR. Among 117 eyes when SF images in straight and peripheral gazes were compared with WF images in straight gaze, NVE were detected in 3 eyes exclusively by WF angiography. Thus, about 2.5% (3/117) eyes had NVE lesion that could not be detected using the SF lens. By a very rough estimation, we might miss one NVE case in every 25 PDR patients if we only use SF lens images in straight and peripheral gazes alone. Our study also revealed that there is improved retinal visualization with WF angiography which can alter the classification of retinopathy, which in turn can influence follow-up and treatment of these patients.
The landmark DR study found that 10% of patients experienced a decline in visual acuity, and 5% showed a constriction of their visual fields. Full-scatter photocoagulation also exacerbates macular edema and causes loss of vision and is associated with other rare complications such as hemorrhage, choroidal detachments, acute angle closure glaucoma, a decrease in color vision, contrast sensitivity, nyctalopia, and lenticular burns. If we capture images at different time points and different quadrants, we are not getting a full picture. With Ultra Widefield Fundus Fluorescein Angiography (UWFFA), the advantage is that we get the entire view of fundus. This helps us in better deliniation of areas of capillary nonperfusion and targeting laser therapy to these areas alone which has brought to the concept of targeted panretinal photocoagulation (PRP). Reddy et al. reported two cases in which ultra-WF fluorescein angiography was used to direct targeted retinal photocoagulation (TRP) to areas of retinal capillary nonperfusion in an attempt to cause regression of diabetic neovascularization. The application of TRP successfully led to the regression of the retinal neovascularization in these patients and complications of conventional PRP such as visual field loss and macular edema was avoided. Hence, when TRP is used in conjunction with ultra WF fluorescein angiography, preservation of functional retina may be possible while minimizing the amount of laser treatment that is applied to the retina. Muqit et al.'s study concluded that Optos-guided TRP using for treatment-naive PDR is a promising procedure with favorable safety profile.
| Conclusion|| |
As evident by our study results, SF images in primary as well as all peripheral gazes tend to miss out on NVE, thereby incorrectly diagnosing PDR eyes as NPDR, which were picked up on WF as having NVE. WF fluorescein angiography improved retinal visualization and will alter the classification of DR and therefore influence follow-up and treatment of these patients. Hence, we propose WF angiography can be considered as gold standard for accurately diagnosing the presence of NVE in eyes with PDR and long-term prospective trials are needed to evaluate the role of targeted PRP in PDR using WF angiography images.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Wild S, Roglic G, Green A, Sicree R, King H. Global prevalence of diabetes: Estimates for the year 2000 and projections for 2030. Diabetes Care 2004;27:1047-53.
Gadkari SS, Maskati QB, Nayak BK. Prevalence of diabetic retinopathy in India: The All India Ophthalmological Society Diabetic Retinopathy Eye Screening Study 2014. Indian J Ophthalmol 2016;64:38-44.
] [Full text]
Yau JW, Rogers SL, Kawasaki R, Lamoureux EL, Kowalski JW, Bek T, et al
. Global Prevalence and Major Risk Factors of Diabetic Retinopathy. Diabetes Care 2012;35:556-64.
Soliman AZ, Silva PS, Aiello LP, Sun JK. Ultra-wide field retinal imaging in detection, classification, and management of diabetic retinopathy. Semin Ophthalmol 2012;27:221-7.
Price LD, Au S, Chong NV. Optomap ultrawide field imaging identifies additional retinal abnormalities in patients with diabetic retinopathy. Clin Ophthalmol 2015;9:527-31.
Wessel MM, Aaker GD, Parlitsis G, Cho M, D'Amico DJ, Kiss S. Ultra-wide-field angiography improves the detection and classification of diabetic retinopathy. Retina 2012;32:785-91.
Talks SJ, Manjunath V, Steel DH, Peto T, Taylor R. New vessels detected on wide-field imaging compared to two-field and seven-field imaging: Implications for diabetic retinopathy screening image analysis. Br J Ophthalmol 2015;99:1606-9.
Silva PS, Cavallerano JD, Sun JK, Soliman AZ, Aiello LM, Aiello LP. Peripheral lesions identified by mydriatic ultrawide field imaging: Distribution and potential impact on diabetic retinopathy severity. Ophthalmology 2013;120:2587-95.
Photocoagulation treatment of proliferative diabetic retinopathy. Clinical application of Diabetic Retinopathy Study (DRS) findings, DRS report number 8. The Diabetic Retinopathy Study Research Group. Ophthalmology 1981;88:583-600.
Reddy S, Hu A, Schwartz SD. Ultra wide field fluorescein angiography guided targeted retinal photocoagulation (TRP). Semin Ophthalmol 2009;24:9-14.
Muqit MM, Marcellino GR, Henson DB, Young LB, Patton N, Charles SJ, et al.
Optos-guided pattern scan laser (Pascal)-targeted retinal photocoagulation in proliferative diabetic retinopathy. Acta Ophthalmol 2013;91:251-8.
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]
[Table 1], [Table 2]