Non-mydriatic fundus photography is an imaging test that photographs the fundus without using dilating drops. In a dark room or a dimly lit room, it encourages the pupils to dilate naturally and observes the posterior pole with a coaxial illumination fundus camera using the indirect method. The standard field of view is 45°, and imaging focuses on the macula, optic disc, and areas around the vascular arcades.
In settings that combine a non-mydriatic wide-field fundus camera and OCT, it is possible to obtain wide-area, highly accurate diagnostic images even without dilation. Depending on the conditions, it may be better than ophthalmoscopic observation for detecting retinal hemorrhage. However, observing the most peripheral retinal findings requires a dilated fundus examination.
It is widely used for screening diabetic retinopathy, glaucoma, AMD, and hypertensive retinopathy. In recent years, combining it with AI (artificial intelligence) automatic analysis has attracted attention for improving screening efficiency1), and use of fundus photography in telemedicine (teleophthalmology) is also expanding2).
It is a device that can photograph the fundus without using dilating drops (eye drops). Images are taken in a dark room after the pupils have naturally widened. It also does not require anesthetic eye drops, and one advantage is that you can go home and drive right after the examination. However, if the pupils do not open enough or if detailed observation of the peripheral back part of the eye is needed, an examination using dilating drops may be necessary.
Non-mydriatic fundus camera (standard type)
Field of view: 45° (imaging centered on the posterior pole)
Anesthesia: No anesthetic eye drops needed
Main imaging modes: color, green (red-free), infrared
Indications: screening for diabetic retinopathy, glaucoma, and AMD
Non-mydriatic wide-field fundus camera
Fundus autofluorescence (FAF)
Principle: detects lipofuscin fluorescence with excitation from short-wavelength blue light (488 nm)
Anesthesia: not needed
Indications: evaluation of AMD, retinitis pigmentosa, and geographic atrophy
Feature: evaluates the metabolic state of the retinal pigment epithelium without using a contrast agent
The diseases below are screening targets for which non-mydriatic fundus photography is especially useful.
Diabetic retinopathy
Main findings: dot hemorrhages, hard exudates, soft exudates, neovascularization
Protocol: Two posterior pole images (centered on the optic disc and macula) are standard
Screening accuracy: Non-mydriatic cameras have good sensitivity and specificity for diabetic retinopathy3)
Diabetes Eye Society GL: Regular fundus examinations are recommended from the first visit6)
Glaucoma
Main findings: enlarged C/D ratio, NFLD (nerve fiber layer defect), optic disc hemorrhage
Evaluation criteria: Further examination if the C/D ratio is 0.7 or higher, or if the difference between the eyes is 0.2 or greater. Further examination if the R/D ratio is 0.1 or lower
Note: Combine this with OCT measurement of retinal nerve fiber layer (RNFL) thickness
AI analysis: Deep learning has high accuracy for automatic detection of glaucomatous optic neuropathy5)
Age-related macular degeneration (AMD)
Main findings: Drusen, retinal hemorrhage, suspected CNV (choroidal neovascularization)
Response: If abnormal findings are present, perform further evaluation with OCT and fluorescein fundus angiography
Risk factors: Older age, smoking, family history
Note: Use fundus autofluorescence (FAF) to assess the extent of geographic atrophy
| Diseases targeted for screening | Main fundus findings | Next step |
|---|---|---|
| Diabetic retinopathy | Dot hemorrhages, white spots, neovascularization | OCT and fluorescein fundus angiography |
| Glaucoma | Increased C/D ratio, NFLD | Visual field testing, OCT-RNFL |
| age-related macular degeneration | drusen and retinal hemorrhage | OCT and ICG angiography |
| hypertensive retinopathy | arteriovenous crossing changes and arteriolar narrowing | collaboration with internal medicine |
| retinal vein occlusion | flame-shaped hemorrhages, venous dilation, and optic disc edema | OCT and fluorescein angiography |
For screening in patients with diabetes, two posterior pole images (centered on the optic disc and macula) are standard. If a wide-angle camera is available, one image may be used instead. After non-mydriatic imaging, adding OCT to evaluate macular edema is recommended. If the stage has progressed to preproliferative or beyond, consider further examination with fluorescein angiography (FA).
It is important to assess changes over time through routine imaging. Comparing with past images improves the ability to detect subtle changes.
The following indicators are used when observing the optic disc.
Normal findings of the optic disc
C/D ratio: 0.3 to 0.6 (large individual variation)
R/D ratio: above 0.1
Rim width: evenly present according to the ISNT rule
Optic disc color: pale orange to orange-red. Clear margins
Findings of the optic disc that need further evaluation
C/D ratio: 0.7 or higher (or an inter-eye difference of 0.2 or more)
R/D ratio: 0.1 or lower
Localized thinning or loss of rim width: often seen at the upper and lower poles
Disc hemorrhage: a sign of glaucoma progression
| Disease | Fundus findings | Notes |
|---|---|---|
| Diabetic retinopathy (nonproliferative stage) | Dot hemorrhages and hard exudates | Hard exudates near the fovea carry a risk of macular edema |
| Diabetic retinopathy (preproliferative stage) | Cotton-wool spots, venous dilation, and IRMA | Further examination with FA and OCT |
| Diabetic retinopathy (proliferative stage) | Neovascularization and vitreous hemorrhage | Indications for panretinal photocoagulation and anti-VEGF |
| AMD (soft drusen) | Ill-defined yellow-white lesions | Further evaluation with OCT is needed |
| AMD (CNV) | Macular hemorrhage and gray-white lesions | Urgent OCT and angiography |
| Hypertensive changes | Arteriovenous crossing changes and arteriolar narrowing | Also useful as an indicator for assessing overall management |
Fundus photographs can detect diabetic retinopathy, glaucoma, age-related macular degeneration, hypertensive retinopathy, and retinal vein occlusion. The shape of the optic disc helps judge suspicion of glaucoma, and the presence or absence of hemorrhage, cotton-wool spots, and neovascularization is used to assess the stage of diabetic retinopathy. Because abnormalities can be found before symptoms appear, regular fundus examinations are important.
The use of mydriatic drops is determined based on the state of the anterior chamber angle and social factors at the visit, such as whether the patient will drive. Confirm the following before dilation.
In routine follow-up exams for stable diabetes and glaucoma, combining a wide-field fundus camera with OCT is often enough without pupil dilation. However, if detailed observation of inflammation inside the eye (uveitis) or the peripheral retina is needed, or at the first visit, a dilated exam is recommended. After dilation, vision becomes blurry for about 4 to 6 hours, but this is temporary.
A non-mydriatic fundus camera is a coaxial-illumination fundus camera (indirect method). It observes the retina through the cornea, lens, and vitreous. It consists of the following components.
Save as digital images in the electronic medical record and use them for comparison of changes over time. A standard resolution of 15 megapixels or higher is recommended. Record the imaging date, eye, imaging direction, and camera settings.
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Sim DA, Keane PA, Tufail A, et al. Automated retinal image analysis for diabetic retinopathy in telemedicine: potential and pitfalls. Ophthalmic Surg Lasers Imaging Retina. 2015;46(6):615-624.
Scanlon PH. The English National Screening Programme for diabetic retinopathy 2003-2016. Acta Diabetol. 2017;54(6):515-525.
Abràmoff MD, Lavin PT, Birch M, Shah N, Folk JC. Pivotal trial of an autonomous AI-based diagnostic system for detection of diabetic retinopathy in primary care offices. NPJ digital medicine. 2018;1:39. doi:10.1038/s41746-018-0040-6. PMID:31304320; PMCID:PMC6550188.
Li Z, He Y, Keel S, et al. Efficacy of a deep learning system for detecting glaucomatous optic neuropathy based on color fundus photographs. Ophthalmology. 2018;125(8):1199-1206.
日本糖尿病眼学会. 糖尿病網膜症診療ガイドライン（第1版）. 日眼会誌. 2020;124(12):955-981.
