Article

CLINICAL: RETINA

A SPLIT DECISION

Did this patient have acquired retinoschisis or a retinal detachment?

A 60-year-old Black male presented for his annual exam sans visual complaints. BCVAs were 20/20 OD and OS, and pupils and ocular motilities were unremarkable. Dilated exam revealed bilateral, large bullous elevations with distinct margins in the temporal retinas. SD-OCT showed splitting of the neurosensory retina OU. I detected no holes or tears. Finally, he had no confrontation VF defects.

Does this patient have an ac-quired retinoschisis or retinal detachment (RD)? To help you decide, here’s an overview of acquired retinoschisis, its clinical symptoms and signs and useful diagnostic devices. (See https://bit.ly/2B2zuQc )

OVERVIEW

Acquired retinoschisis is a common peripheral lesion, also known as peripheral, degenerative or senile retinoschisis. It is present in about 4% of patients age 40 or older and affects men and women equally, according to Ophthalmology. A total of 82% of cases are bilateral.

The condition is due to coalescing cystic lesions in peripheral microcystoid degeneration, resulting in separation or splitting the retina into an inner and outer layer. Clinically, retinoschisis is dome-shaped with minimal retinal pigment epithelium (RPE) alterations or atrophy, and commonly located in the inferior temporal retina. The inner retinal layer has a “beaten metal” or “pitted” appearance with small, glistening, yellow-white deposits. The outer retinal layer has a honey‐combed appearance with crater‐like excavations, also known as outer‐layer breaks, according to Ophthalmology. There are no vitreous pigment cells, retinal tears or demarcation lines as seen in RD.

Most cases of retinoschisis do not affect vision and are non-progressive. But, some cases may progress to involve the macula or to an RD. Risk factors for an RD: a family history or the presence of retinal holes or breaks.

CLINICAL SYMPTOMS

Acquired retinoschisis rarely produces symptoms, unless complicated by an RD, and is typically found during a routine dilated retinal examination.

CLINICAL SIGNS

Two types of lesions occur in acquired retinoschisis:

  1. Typical. These are flat, or have shallow elevation. A split in the retina’s outer plexiform layer causes them. It is uncommon for this type to progress, or form outer retinal holes, so, the risk for an RD is low.
  2. Reticular. These are bullous or have a dome-shape elevation. A nerve fiber layer split causes them. This lesion appears as an immobile, transparent elevation with well-demarcated borders that have visible vasculature and an overall smoother appearance than an RD. Yet, this lesion tends to have a higher risk of producing retinal holes and, thus, a higher risk of progression to an RD. You may see retinal holes or breaks in the outer or inner retinal layer of these lesions. However, outer holes are more common and are usually large (greater than 3-disc diameters) and if chronic, a cuff of subretinal fluid may create a ring of pigmentation. Outer and inner retinal layer holes are associated with symptomatic, rapidly progressive RD that requires urgent surgical treatment.

Does the patient have acquired retinoschisis or retinal detachment?
Image courtesy of Dr. Reynolds

DIAGNOSTIC DEVICES

  • Goldman 3-mirror lens. Used to evaluate the immobile, dome elevation of the lesions.
  • Scleral indentation. This flattens a true RD.
  • SD-OCT. This shows an outer plexiform layer break in acquired retinoschisis vs. an RD from the RPE.
  • VF. Typically, patients have no VF complaints, but neurosensory retina splitting results in an absolute VF defect in the affected area. RD patients have a relative VF defect. This can be tested with perimetry or by holding a scleral depressor on the observer’s side of the condensing lens and documenting whether the patient can see the depressor’s shadow (indirect ophthalmoscope perimetry).
  • Ultrasound B-scan. This shows a decrease in the space between the retina and sclera in a true RD.
  • Ultra-widefield imaging. This helps to detect and monitor retinoschisis.

THE ANSWER

If you diagnosed the above patient with acquired retinoschisis, you are correct! The patient was referred to a retinal specialist and monitored closely with serial OCT. Unfortunately, his retinoschisis progressed to an RD.

A number of treatment options are available for symptomatic acquired retinoschisis, ranging from photocoagulation, to pneumatic retinopexy, to scleral buckle with vitrectomy and silicone oil, depending on the location of the outer retinal break, foveal involvement and presence of proliferative vitreoretinopathy.

Acquired retinoschisis and RD may mimic each other. Misdiagnosed patients are at risk for vision-threatening complications, including an RD. Advanced imaging technology can lead to a faster diagnosis, prompt referral for treatment and improved management of retinoschisis patient. OM