Retinal folds are creases or wrinkles that develop in the retina, the light-sensitive layer of tissue at the back of the eye. This is not a disease itself but a physical sign of an underlying issue. The presence of a fold can have a wide range of effects on a person’s sight. A minor fold located in the peripheral retina may cause no noticeable symptoms, while in other cases, it can lead to significant visual impairment depending on its size and location.
Understanding the Retina’s Structure
To understand how retinal folds affect vision, it is helpful to know about the retina’s anatomy. The retina is located in the posterior part of the eye and functions much like the sensor in a digital camera. Its primary role is to receive focused light, convert it into neural signals, and send these signals to the brain through the optic nerve for interpretation.
The retina is composed of multiple, distinct layers of cells. Among these are the photoreceptor cells, known as rods and cones, which are responsible for detecting light and color. A small, specialized area called the macula is responsible for our sharpest, most detailed central vision. Because of this intricate structure, any physical disruption like a fold can displace these cell layers, leading to distorted or lost vision.
Causes of Retinal Folds
Some retinal folds are congenital, meaning they are present at birth. These can result from genetic or developmental conditions that affect how the eye forms, such as familial exudative vitreoretinopathy (FEVR). Retinopathy of prematurity (ROP), a condition affecting infants born significantly premature, can also lead to folds due to abnormal blood vessel growth.
Folds can also appear as a complication following certain eye surgeries. Procedures to repair a detached retina can lead to the formation of scar tissue on the retina’s surface. This process, known as proliferative vitreoretinopathy, can contract and pull on the retina, causing it to fold as it heals. The use of an intraocular gas bubble during surgery to hold the retina in place can sometimes contribute to this process.
Direct physical injury to the eye or head is another recognized cause. Trauma can exert forces that disrupt the delicate retinal tissue, leading to folds. In infants, abusive head trauma is a documented cause of retinal folds. This is due to the violent acceleration-deceleration forces that can cause the vitreous gel inside the eye to pull on the retina.
Other diseases within the eye can indirectly cause the retina to fold. Conditions like ocular tumors or chronic inflammation, known as uveitis, can create pressure or traction on the retina. This mechanical stress can physically push or pull the retina out of its normal position. Issues outside the eye, such as idiopathic intracranial hypertension, can also cause folds by flattening the back of the eye.
Diagnosis and Associated Symptoms
The signs of a retinal fold can vary. Many individuals are asymptomatic, with the fold discovered during a routine eye exam. When symptoms occur, they often include blurred vision or metamorphopsia, a visual distortion where straight lines appear wavy. Some people might notice a scotoma, a blind or dark spot in their field of vision.
An ophthalmologist diagnoses retinal folds during a dilated eye exam. To confirm the diagnosis and assess the fold, specialized imaging tests are used. Optical coherence tomography (OCT) is a non-invasive technology that uses light to create high-resolution, cross-sectional images of the retina, clearly showing the undulation of the retinal layers.
A practitioner may use fundus photography to document the fold’s appearance and monitor it over time. If the view is obscured by a cataract or bleeding, B-scan ultrasonography may be employed. This technique uses sound waves to create an image of the intraocular structures, helping to identify the fold when a direct view is not possible.
Approaches to Treatment
The management strategy for a retinal fold is determined by its underlying cause, location, and impact on vision. Not all folds require active treatment. If a fold is small, situated in the peripheral retina where it doesn’t affect central vision, and shows no signs of progressing, an ophthalmologist may recommend observation with regular monitoring.
When a fold affects or threatens central vision, surgical intervention is often the course of action. The main surgical procedure is a vitrectomy, which involves the careful removal of the vitreous gel that fills the inside of the eye. Removing the vitreous relieves the traction or pulling forces on the retina, allowing it to relax and flatten back into its proper position.
During a vitrectomy, a surgeon may also perform a technique called membrane peeling. This delicate procedure involves using fine instruments to remove any scar tissue or epiretinal membranes from the surface of the retina that are causing it to wrinkle. The decision to proceed with surgery is made after carefully weighing the potential for visual improvement against the inherent risks of any intraocular procedure.