Retinodialysis

Retinodialysis (ret·i·no·di·al·y·sis), from the Latin rete (net) and Greek dia (through) + lysis (a loosening), is a specific type of tear of the retina from its attachment point at the ora serrata. The ora serrata is the anatomical junction where the retina meets the ciliary body, marking the retina's most anterior border. Unlike a more common retinal tear or hole which occurs in the body of the retinal tissue, a dialysis is a disinsertion or avulsion of the retinal base.

Anatomy and Pathology

The retina is the neural, light-sensitive tissue lining the back of the eye. Anteriorly, it extends to just behind the ciliary body, a muscular structure involved in focusing the lens. The serrated, scalloped edge where the retina attaches here is the ora serrata. In retinodialysis, the retina is physically torn away from this insertion point.

This separation creates an opening that allows vitreous fluid (the gel-like substance filling the eye) to pass through and accumulate behind the retina. This fluid buildup leads to a retinal detachment, lifting the retina away from its underlying blood supply (the choroid) and causing vision loss. Retinal detachments originating from a dialysis often progress slowly, as the tear is located far in the periphery.

Causes and Risk Factors

The most common cause of retinodialysis is ocular trauma, particularly blunt force injury. The mechanics of the injury involve a sudden compression and expansion of the eyeball, which puts shearing forces on the vitreous base and its firm attachment to the ora serrata, leading to the disinsertion.

• Common Causes:
  • Direct blow to the eye from a fist, ball (e.g., basketball, soccer ball), or other object.
  • Motor vehicle accidents.
  • Airbag deployment.

While trauma accounts for the majority of cases, spontaneous or idiopathic retinodialysis can also occur, though it is much rarer. It is sometimes seen in association with congenital or developmental abnormalities of the eye. Because it is so strongly linked to trauma, retinodialysis is more commonly diagnosed in young males.

Signs and Symptoms

A person with retinodialysis may not experience immediate symptoms, especially if the resulting retinal detachment is slowly progressing. When symptoms do appear, they are characteristic of a retinal detachment and can include:

• Floaters: A sudden appearance or increase in specks, webs, or strands drifting in the field of vision.
• Photopsia: Flashes of light, particularly in the peripheral vision.
• A "curtain" or shadow: A dark, curtain-like shadow that starts in the peripheral vision and gradually moves across the central visual field.
• Blurred vision or a significant decrease in visual acuity as the detachment progresses toward the macula (the center of the retina).

It is crucial to seek immediate medical attention from an ophthalmologist if these symptoms occur.

Diagnosis

An ophthalmologist diagnoses retinodialysis during a comprehensive, dilated eye examination. The key diagnostic techniques include:

• Indirect Ophthalmoscopy: Using a bright light and a special lens, the doctor can view the entire retina, including the far periphery.
• Scleral Depression: This is a critical technique for diagnosing retinodialysis. The ophthalmologist gently presses on the outside of the eyelid with a small instrument to indent the sclera (the white of the eye). This brings the ora serrata into view, allowing for the direct visualization of the disinserted retina. The edge of the dialysis often appears rolled or folded.

Imaging techniques like wide-field fundus photography may also be used to document the tear and the extent of the associated retinal detachment.

Treatment

Retinodialysis requires surgical intervention to reattach the retina and prevent permanent vision loss. The goal of surgery is to seal the tear and drain the subretinal fluid, allowing the retina to settle back into its proper position.

Common treatment methods include:

• Scleral Buckling: This is often the preferred surgical procedure for retinodialysis. A silicone band or sponge is sutured onto the outside of the sclera over the location of the tear. This buckle indents the eye wall, pushing it inward to support the retinal tear and close it. Cryotherapy (freezing) or laser photocoagulation is applied around the dialysis to create a permanent adhesive scar, sealing the retina to the underlying tissue.
• Vitrectomy: In some cases, a vitrectomy may be performed. This procedure involves removing the vitreous gel from the eye, which relieves traction on the retina. The surgeon then reattaches the retina from inside the eye and uses laser to seal the tear. The eye is then filled with a gas bubble or silicone oil to hold the retina in place while it heals.

The prognosis for vision recovery is generally good if the detachment is repaired before the macula is affected.