Retinal diseases in Paris and Cachan

ANATOMY AND FUNCTION

What is the retina? Function and structure

The retina is a thin nerve membrane, less than half a millimetre thick, that lines the inner surface at the back of the eye. It is the eye’s equivalent of a photographic sensor: it converts the light rays focused by the cornea and the lens into electrical signals, transmitted to the brain via the optic nerve to be interpreted as an image.

It is divided into two distinct functional zones. The central retina, dominated by the macula, is responsible for precise, colour vision and fine detail — reading, face recognition, driving. At the centre of the macula lies the fovea, the area of maximum concentration of cones (the photoreceptors of daytime vision), which produces the highest visual acuity. The peripheral retina, for its part, provides the lateral visual field, night vision and motion perception, thanks to a high density of rods.

The retina is a non-regenerating nerve tissue: any established damage is permanent. This is why the speed of diagnosis and management is decisive in preserving visual function.

RETINAL DISORDERS

The main retinal diseases

Retinal disorders are varied: degenerative (AMD), vascular (diabetic retinopathy), mechanical (detachment), or related to changes in the vitreous (epiretinal membrane, floaters). Each condition has a dedicated page with its full work-up and treatment.

WARNING SIGNS

When to seek care — and when to act urgently

Certain symptoms should prompt a same-day consultation in a specialist unit, without waiting for a scheduled appointment:

• Sudden appearance of a dark curtain or veil in the visual field, even partial — a classic sign of retinal detachment.
• Sudden shower of floaters (numerous spots or threads appearing within minutes), whether or not accompanied by flashes of light (photopsias): suggests a retinal tear or an early detachment.
• Repeated flashes of light (perceived in darkness or when closing the eyes) indicating vitreoretinal traction.
• Sudden loss of central vision or the appearance of a fixed dark patch at the centre of vision: may reflect subretinal neovascularisation (wet AMD) or a vascular occlusion.
• Distortion of straight lines (doors, windows, tiling appear curved) — metamorphopsia — a macular sign pointing towards an epiretinal membrane or macular oedema.

RETINAL INVESTIGATIONS

Retinal examinations at the practice

The retinal work-up relies on several non-invasive or minimally invasive examinations, carried out at the Cachan practice:

Macular OCT (optical coherence tomography)

OCT is the central examination of the retinal work-up. It produces high-resolution cross-sectional images of the retina within seconds, without contact and without preparation. It allows all retinal layers to be visualised, the macular thickness to be measured, and the detection of oedema, subretinal neovascularisation, pigment epithelial detachment or vitreoretinal traction. OCT-A (OCT angiography) complements this examination by mapping vascular flow without dye injection.

Fundus examination

The fundus examination provides a direct view of the retina, the optic disc and the retinal vessels. It is performed after pupil dilation. It is the reference screening examination for diabetic retinopathy (tele-screening possible), the assessment of arterial hypertension or the routine monitoring of high myopia.

Retinal angiography with fluorescein or indocyanine green

Angiography requires an intravenous injection of a dye that circulates in the retinal vessels. A series of sequential images maps the retinal and choroidal circulation, detects areas of vascular leakage (ischaemia, neovascularisation) and guides treatment decisions (intravitreal injection, laser). This examination is performed according to clinical indications.

TREATMENTS

Treatments for retinal diseases

The management of retinal disorders draws on several complementary approaches, chosen according to the condition, its stage and how it is progressing:

Intravitreal injections (IVI)

Intravitreal injections deliver anti-VEGF medicines (which block neovascularisation) or long-acting corticosteroids directly into the eye. They are the standard treatment for wet AMD, diabetic macular oedema and certain retinal vein occlusions. The procedure is carried out under strict sterile conditions, as an outpatient. The dedicated page on intravitreal injections details how the procedure is carried out and the follow-up.

Retinal laser photocoagulation

Retinal laser is used to seal peripheral retinal tears (prevention of detachment), treat areas of ischaemia in proliferative diabetic retinopathy (panretinal photocoagulation) or close microaneurysms responsible for oedema. The procedure is generally performed during a consultation, after pupil dilation, without general anaesthesia.

Vitrectomy

Vitrectomy is the reference surgical procedure for conditions requiring direct access to the retina: epiretinal membrane, macular hole, complex retinal detachment, non-resolving vitreous haemorrhage. It is performed at the Clinique Sainte-Geneviève under local or general anaesthesia depending on the indications. The dedicated page on vitrectomy presents the techniques and the recovery.

FREQUENTLY ASKED QUESTIONS

Frequently asked questions about the retina

This article is intended for general information and does not replace a medical consultation. The diagnosis of retinal diseases and the choice of a treatment rely on a complete ophthalmic examination with a fundus examination and imaging (OCT). If you experience flashes of light, a shower of dark spots, a veil or a sudden loss of vision, seek urgent care from an ophthalmologist.