Teenager previously diagnosed with ‘lazy eye’ has retinal findings

In color testing, he missed all plates with the left eye.

Benjamin P. Casella

A 16-year-old African American man presented for a second opinion regarding a diagnosis of “lazy eye” in the left eye. He stated that, about a year ago, he noticed a wavy line in his left eye’s vision. He then went to sleep and woke up with severe blur in that eye but no pain.

The patient went unchecked for a period of months before presenting to an eye doctor. At that visit, the doctor apparently told him he was born with a lazy eye and just happened to notice his amblyopia later in life. That was his first eye examination.

Figure 1. A mosaic of the left posterior pole. Notice the fibrotic bands and focal areas of vascular tortuosity. In addition, notice the tractional folds near the fovea. Images: Casella BP

Medical and family histories were unremarkable, and he was taking no medications. He also denied trauma. Entering visual acuities were 20/20 in the right eye and count fingers at 5 feet in the left eye with no improvement on pinhole. Confrontation fields were full in all quadrants in each eye. Extraocular muscle function was normal in both eyes. Pupils were equal and reactive and there was a moderate afferent pupillary defect in the left eye.

Color vision was tested using Ishihara plates. The right eye missed no plates, and the left eye missed all plates, although the patient stated he could discern the colors. The patient was essentially orthophoric at distance and near.

Retinoscopy and refraction yielded +0.25 DS in the right eye with 20/20 visual acuity and +5.00 DS in the left eye with no improvement of visual acuity. Anterior segment evaluation was unremarkable in each eye, and intraocular pressures were 12 mm Hg OD and 11 mm Hg OS.

Dilated fundus evaluation of the right eye was significant for an area of lattice degeneration with multiple atrophic retinal holes inferiorly in the periphery. Also, there was a large area of subretinal fluid with highly adherent vitreous adjacent to one of the retinal holes. These findings were too peripheral to be photographed.

The disc, macula and vessels of the right eye were all normal. Dilated fundus evaluation of the left eye showed several atrophic retinal holes and an area of shallow retinoschisis temporally in the left retinal periphery that were unable to be photographed.

What is your diagnosis?

The photograph clearly demonstrates a left chronic macula-off retinal detachment. However, the rigid retinal folds, focal arteriolar tortuosity and fibrosis indicate a potentially devastating response to the detachment known as proliferative vitreoretinopathy (PVR).

Pathophysiology

The exact pathophysiology of PVR is still poorly understood, but it rests on the following supposition: when the retina is insulted, it will attempt to heal itself. A common example of this phenomenon is the formation of an epiretinal membrane after vitreous detachment, in which glial cells migrate and proliferate in response to tiny breaks in the internal limiting membrane.

PVR is a clinically descriptive term designating a complex and multifactorial proliferative response to retinal insult. Its presence is a guarded to poor prognostic indicator and, to this day, remains the most common reason for failure of retinal detachment repair. Several cell types are implicated in PVR, including glial cells, retinal pigment epithelium (RPE) cells and fibroblasts.

Figures 2 and 3. OCT images of the left macular region. Notice the marked areas of focal retinal elevation (especially as shown with the 3-D module). Could these elevated areas account for the significant degree of hyperopia in the left eye?

Glial cells function to support neurons and make up about 50% of the mass of the central nervous system. They migrate and proliferate in an effort to insulate and protect neurons, such as retinal ganglion cells, when they are insulted. When RPE cells are insulted or become detached from the neurosensory retina, they trigger the release of macrophages, which is evidence for an inflammatory component in early PVR. In addition, the simple exposure of RPE cells, themselves, to vitreous can be sufficient to trigger inflammation.

Fibroblast proliferation causes contraction of the affected tissue, yielding tractional membranes, retinal rigidity, vascular tortuosity and retinal folds in PVR. It is important to note that these fibrotic membranes can occur on either or both sides of the neurosensory retina and can lead to subsequent retinal breaks. The extent of PVR can range from mild and focal to severe and panretinal.

Surgical intervention

The contraction and subsequent disruption of some or all layers of the neurosensory retina caused by PVR is, in many cases, irreversible. However, surgical intervention can provide some benefit and should be considered in all cases of PVR. The goal of surgery is to relieve traction on the retina while reattaching it.

Vitrectomy and membrane peel are often required along with repair of the detachment. While successful reattachment of the retina has been reported in many cases, the rate of significant visual recovery is low. This disconnect between structural and functional success rates can be attributed to the fact that retinal contraction, entanglement and fibrosis cause functional loss that may not be repairable, even with the achievement of an anatomically “normal” post-surgical retina.

Due to the relatively poor visual prognosis of PVR, there is a significant amount of research being done in an attempt to figure out how to modulate the cascade of events that leads to its development. Anti-inflammatory drugs are on the list of medications being considered as a means of accomplishing this task. Truly, the future of PVR management will rely more heavily on the prevention of this potentially devastating condition rather than a cure.

This patient’s management

The large area of subretinal fluid in the patient’s right eye indicated a rhegmatogenous retinal detachment (macula-on). We promptly referred him to a retina specialist, who confirmed this diagnosis as well as that of the chronic macula-off detachment in the left eye with PVR.

The right eye underwent indirect laser and scleral buckle. Unfortunately, the patient had a severe IOP spike the night of the surgery and presented to the retina specialist the next morning with a central retinal artery occlusion (a known risk of this procedure). He and his mother are weighing their options on whether to have the left eye operated on in an attempt to restore some visual function.

The patient left our clinic with a polycarbonate lens and full-time spectacle prescription in anticipation of the poor prognosis.

‘Amblyogenic’ considerations

The patient’s moderately high hyperopia in the left eye presents a somewhat chicken-and-egg clinical conundrum. The OCT scans through the left macula using Cirrus HD-OCT (Carl Zeiss Meditec, Dublin, Calif.) show areas of severe retinal elevation. Moderate to severe macular elevation will likely be interpreted as relative hyperopia on retinoscopy and refraction. This is why many patients with central serous retinopathy will often refract slightly more hyperopic (or less myopic).

On the other hand, the patient could have been close to +5.00 DS in the left eye before the retina detached. Either way, perhaps the most important aspect of this case is the fact that, with little to no exception, amblyopia should not be diagnosed without careful fundus examination through a dilated pupil.

References:

• Asaria RHY, Kon CH, Brunce C, et al. How to predict proliferative vitreoretinopathy. Ophthalmology. 2001;108:1184-1186.
• Leaver PK. Proliferative vitreoretinopathy. Br J Ophthalmol. 1995;79:871-872.
• Van Horn DL, Aaberg TM, Machemer R, Fenzl R. Glial cell proliferation in human retinal detachment with massive periretinal proliferation. Am J Ophthalmol. 1977;84:383.
• Waters T, Vollmer L, Sowka J. Proliferative vitreoretinopathy as a late complication of blunt ocular trauma. Optometry. 2008;79:197-202.

• Benjamin P. Casella, OD, FAAO, can be reached at 767 Broad Street, Augusta, GA 30901; (706) 722-0817; fax: (706) 722-0208; bpc81@aol.com.