The perception of a dark curtain in the visual field — a fixed shadow, a progressive black veil, or a sudden loss of part of the visual field — is one of the most urgent reasons for consultation in ophthalmology. Whether it appears suddenly or develops over several hours, this symptom almost always indicates a serious disorder of the retina or ocular vasculature. Understanding its mechanisms, causes, and diagnostic approach enables prompt action and preservation of vision. Dr Julien Gozlan, ophthalmologist in Paris 16, explains how to recognise this warning sign, which conditions are responsible, and what emergency treatments can be offered.
How does a dark curtain in the visual field present?
The dark curtain corresponds to an area of darkness that invades part of the visual field of one eye, sometimes both. The patient typically describes the sensation of an opaque veil falling from above, rising from below, or advancing laterally, masking an ever-increasing portion of what they perceive. The onset may be sudden — within seconds to minutes — or progressive over several hours.
It is essential to distinguish this symptom from benign situations such as a simple transient blurring of vision due to fatigue, temporary dry eye, or an ophthalmic migraine with aura. The dark curtain is characterised by its persistence, its fixed or extensive nature, and the absence of rapid spontaneous recovery. It is frequently preceded, in the hours or days prior, by the sudden appearance of floaters (vitreous floaters) or flashes of light (photopsias) — two warning signs that should already prompt urgent consultation.
The dark curtain may affect peripheral vision before progressing towards the centre. When it reaches the macula — the central zone of the retina responsible for fine vision — the reduction in visual acuity becomes significant and the potential sequelae irreversible.
What are the causes of a dark curtain?
Several serious ocular conditions can cause this symptom. Each has a distinct mechanism, but all share one common feature: the necessity for rapid diagnosis and management.
Retinal detachment
Retinal detachment is the most frequent and most feared cause of a dark curtain. The neurosensory retina separates from the underlying retinal pigment epithelium, interrupting the nutritional supply and the functioning of the photoreceptors in the detached zone. The patient then perceives a shadow corresponding exactly to the elevated retinal territory. The detachment often begins in the periphery and progresses towards the centre if no treatment is undertaken. It most commonly occurs following a retinal tear, favoured by high myopia, a history of ocular surgery, trauma, or the natural ageing of the vitreous.
Intravitreal haemorrhage
When bleeding occurs within the vitreous cavity — the space filled with transparent gel situated between the lens and the retina — blood partially or completely blocks the transmission of light. The patient describes a dark red or black veil, sometimes associated with a shower of floaters. The main causes are proliferative diabetic retinopathy, a retinal tear with associated bleeding, or, more rarely, age-related macular degeneration in its complicated exudative form.
Retinal vascular occlusion
Obstruction of a retinal artery or vein abruptly deprives an area of the retina of its blood supply. Occlusion of the central retinal artery causes massive and sudden loss of vision, whilst a branch occlusion results in a sectorial visual field defect perceived as a localised dark curtain. These events are often linked to cardiovascular risk factors: arterial hypertension, diabetes, cardiac arrhythmia, and atherosclerosis. Venous occlusion is frequently accompanied by retinal oedema and haemorrhages visible on fundoscopy.
Isolated retinal tear with localised elevation
Before a complete retinal detachment develops, a tear may cause localised retinal elevation, responsible for a partial veil in the visual field. This stage represents a valuable therapeutic window: treated in time with laser, it can prevent progression to an extensive detachment requiring major surgery.
Other less common causes
Certain severe posterior uveitides, intraocular tumours (choroidal melanoma in particular), or massive papilloedema may also manifest as visual field loss. These diagnoses remain less frequent but must be systematically considered during the assessment.
Clinical examination and investigations
Faced with a dark curtain, the ophthalmologist conducts a rigorous and rapid diagnostic process to identify the cause and direct treatment without delay.
History taking clarifies the circumstances of onset (sudden or progressive), the location of the shadow in the visual field, associated symptoms (floaters, flashes, reduced acuity), and the patient's history (myopia, diabetes, ocular surgery, recent trauma).
Measurement of visual acuity quantifies the functional impact and indicates whether the macula is affected.
Slit-lamp examination assesses the anterior segment of the eye and looks for indirect signs (inflammatory cells in the vitreous, visible haemorrhage).
Dilated fundoscopy is the key examination. Performed after instillation of mydriatic drops, it allows direct visualisation of the retina across its entire surface, enabling identification of a tear, retinal elevation, haemorrhage, or vascular occlusion. Examination with a three-mirror contact lens completes the exploration of the retinal periphery.
B-mode ocular ultrasonography is essential when the fundus is not visible — typically in cases of dense intravitreal haemorrhage preventing any visualisation of the retina. It detects an underlying retinal detachment with excellent sensitivity.
Optical coherence tomography (OCT) provides a detailed analysis of the retinal layers, particularly useful for assessing the condition of the macula and guiding the visual prognosis.
Where vascular occlusion is suspected, fluorescein angiography may be performed to map retinal perfusion and identify the ischaemic zone. A complementary cardiovascular work-up is then systematically requested.
Treatment according to the identified cause
Treatment is dictated by the diagnosis and must often be implemented within hours of symptom onset.
- Retinal detachment: surgery is the only treatment. Depending on the extent and location, the retinal surgeon proposes a vitrectomy (removal of the vitreous, repositioning of the retina, tamponade with gas or silicone oil) or scleral buckling (external indentation of the ocular wall). When operated before the macula has detached, the visual prognosis is excellent.
- Isolated retinal tear: laser photocoagulation, performed as an emergency in the clinic, creates a cicatricial barrier around the tear and prevents extension to a full detachment. This procedure is rapid, painless, and highly effective when carried out promptly.
- Intravitreal haemorrhage: close monitoring is initiated if the haemorrhage is moderate and the retina intact on ultrasonography. In cases of dense persistent haemorrhage or an underlying cause requiring treatment (tear, proliferative diabetic retinopathy), a vitrectomy is scheduled.
- Retinal arterial occlusion: this is a maximum emergency. Reperfusion attempts (ocular massage, anterior chamber paracentesis, vasodilators) may be proposed within the first hours, but the visual prognosis often remains guarded. Cardiovascular aetiological work-up is a priority to prevent stroke.
- Retinal venous occlusion: treatment is based on managing the associated macular oedema with intravitreal injections of anti-VEGF agents or corticosteroids, alongside treatment of systemic risk factors.
When should you seek emergency consultation?
Any appearance of a dark curtain in the visual field, whether sudden or rapidly progressive, requires emergency ophthalmological consultation within the following hours, day or night, on weekdays or at weekends. The absence of pain should never be reassuring: retinal detachment is entirely painless. Similarly, a veil still limited to the peripheral visual field should not encourage delay, as it can spread rapidly towards the macula and permanently compromise central vision. If you have noticed in the preceding days an increase in floaters or flashes of light, consultation is all the more justified.
FAQ: frequently asked questions about the dark curtain in the visual field
Can a dark curtain in the visual field disappear spontaneously?
No. Unlike certain benign floaters that diminish over time, a dark curtain indicates a structural or vascular disorder of the retina. It does not resolve without treatment. Even if the veil appears to stabilise, the underlying cause persists and may worsen at any moment. Emergency consultation remains essential.
Is retinal detachment painful?
No, retinal detachment is entirely painless. This is precisely what makes it dangerous: the absence of pain may lead the patient to underestimate the severity of the symptom and delay consultation. Never rely on the absence of pain to assess the urgency of a dark curtain.
Can surgery for retinal detachment be performed as an emergency at night or at weekends?
Yes. Ophthalmic surgery centres have surgical on-call cover for retinal emergencies. Once the diagnosis of retinal detachment is confirmed, the procedure can be scheduled within the following hours, including outside of normal working hours. The time factor is critical for the visual prognosis.
Are myopic individuals at greater risk?
Yes. High myopia (greater than -6 dioptres) is a major risk factor for retinal tear and detachment. Elongation of the eyeball weakens the peripheral retina and promotes posterior vitreous detachment, the initial mechanism underlying most retinal tears. Regular fundoscopic monitoring is recommended in highly myopic patients.
What is the difference between a dark curtain and an ophthalmic migraine?
Ophthalmic migraine with visual aura produces transient luminous phenomena (scintillations, zigzag lines, scintillating scotoma) that typically last 15 to 30 minutes before disappearing completely. The dark curtain, by contrast, is a fixed, persistent, and non-scintillating area of shadow that does not resolve. In cases of doubt, emergency consultation allows a rapid distinction to be made.
📍 Consultation at the Paris – Auteuil Ophthalmology Practice
Dr Julien Gozlan sees retinal emergencies at his practice located in the 16th arrondissement of Paris. Equipped to perform fundoscopy, ocular ultrasonography, and OCT on the same day, he ensures immediate diagnosis and directs patients towards appropriate surgical management when necessary.
Book an Appointment on DoctolibFurther reading
- Retinal detachment: causes, symptoms and treatment: retinal surgical emergency, diagnosis and management.
- Floaters: should you be concerned?: the warning signs that often precede a dark curtain.
- Flashes of light and photopsias: another alarm signal of retinal tear.
- Diabetic retinopathy: screening and management of proliferative forms.