Elevated bullous lesion found in older man during routine exam

The patient had no complaints but had diabetes.

A 60-year-old white man came into our clinic for new glasses. He was taking haloperidol tablets 0.5 mg once daily for Huntington’s chorea, metformin HCl tablets 500 mg twice daily for diabetes mellitus type 2 and simvastatin tablets 40 mg once daily for cholesterol.

His medical history also included colonic polyp, onychomycosis, hydrocele and scabies, and he was overweight.

The examination of the posterior segment and periphery of the right eye was unremarkable. Images: Bockin DG

The patient’s best corrected visual acuity was 20/20 in each eye with a manifest refraction of OD -4.75 D +1.75 D X 175 and OS -5.50 D +2.25 D X 010 and a bifocal add of +2.25 D. Versions were smooth and full, and confrontation visual fields were full in the right eye, but the left eye showed a superior temporal constriction. Pupils were equal, round and reactive to light.

His IOP was 11 mm Hg in both eyes. Examination of the anterior chamber was unremarkable with mild nuclear lenticular changes.

The posterior segment and periphery of the left eye had an elevated bullous lesion in the peripheral fundus.

The examination of the posterior segment and periphery of the right eye was unremarkable. The posterior segment and periphery of the left eye had an elevated bullous lesion in the peripheral fundus.

What is your diagnosis?

Differential diagnoses include retinal detachment, choroidal detachment, “white without pressure” and retinoschisis.

In rhegmatogenous retinal detachment the surface is corrugated in appearance and can be seen to move with eye movements. In addition, the retinal vasculature is often wrinkled, and the choroidal vasculature is obscured. It often shows a pigmented demarcation line at the posterior extent of the detachment, intraretinal cysts, fixed folds or white dots underneath the retina (subretinal precipitates) or a combination of these. A longstanding retinal detachment may resemble retinoschisis. The detachment has a relative scotoma, while retinoschisis shows an absolute visual field defect.

Choroidal detachment shows an orange-brown and more solid appearance than retinal detachment, and hypotony is usually present.

White without pressure is an optical phenomenon secondary to enhanced vitreoretinal adherence in which the fundus changes its usually orange-red color to a translucent grayish white without physical pressure. This condition can occur in a small isolated area or be seen as a circumferential band that travels the entire perimeter of the retina. The circumferential band can have smooth or scalloped margins.

Acquired/age-related degenerative retinoschisis is commonly bilateral and usually inferiotemporal, no pigment cells or hemorrhage are present in the vitreous, the retinal vessels are often sheathed peripherally and white “snowflakes” are often seen on the inner retinal layers.

I diagnosed the patient with retinoschisis in the left eye without retinal breaks and no diabetic retinopathy.

Retinoschisis is characterized by the abnormal splitting of the retina’s neurosensory layers, usually in the outer plexiform layer, resulting in a loss of vision in the corresponding visual field in some rarer forms. More common forms are usually

asymptomatic. The diagnosis is usually clinical and does not require digital imaging, fluorescein angiography or ultrasound.

Schisis is derived from the Greek word meaning splitting, describing the splitting of the retinal layers from each other. In retinoschisis, the neural and epithelial layers of the retina (inner/outer) split. However, schisis is a word fragment, and the term retinoschisis should be used. If the retinoschisis involves the macula, central vision is lost, and this is one form of macular disease. Although some may describe it as a “degeneration,” the term “macular degeneration” should be reserved for “age-related macular degeneration.”

Degenerative retinoschisis

Degenerative retinoschisis is common, with a prevalence of up to 7% in patients older than 40. Its etiology is unknown. It can easily be confused with retinal detachment by the nonexpert observer, and in difficult cases even the expert may have difficulty differentiating the two.

Such differentiation is important because retinal detachment nearly always requires treatment, while retinoschisis itself never requires treatment unless it leads to retinal detachment, which is rare. There is no documented case of degenerative retinoschisis itself (as opposed to the occasional retinal detachment complicating retinoschisis) in which the splitting of the retina has progressed through the fovea. Degenerative retinoschisis is not known to be a genetically inherited condition.

Hereditary retinoschisis

It is estimated that hereditary retinoschisis is much less common and affects one in 5,000 to 25,000 individuals, primarily young males.

Retinoschisis can be caused by an X-linked genetic defect, affecting the vision of men who inherit the disease from their unaffected carrier mothers. The genetic form of this disease usually starts during childhood and is called X-linked juvenile retinoschisis or congenital retinoschisis. Affected males are usually identified in grade school but occasionally are identified as young infants.

Few affected individuals go completely blind from retinoschisis. Visual acuity can be reduced to less than 20/200 in both eyes. Individuals affected by X-linked juvenile retinoschisis are at an increased risk for retinal detachment and eye hemorrhage, among other potential complications.

Retinoschisis causes acuity loss in the center of the visual field through the formation of tiny cysts in the retina, often forming a “spoke-wheel” pattern that can be subtle. Vision loss is caused by nerve tissue damaged from the cysts.

Traditional retinoschisis

Tractional retinoschisis may be present in conditions causing traction on the retina, especially at the macula. This may occur in the vitreomacular traction syndrome, from proliferative diabetic retinopathy with vitreoretinal traction and atypical cases of impending macular hole.

Exudative retinoschisis

Exudative retinoschisis involves the central part of the retina secondary to an optic disc pit and was erroneously considered to be a serious retinal detachment until correctly described by Lincoff as retinoschisis. Significant visual loss may occur. After a period of observation for spontaneous resolution, treatment with temporal peripapillary laser photocoagulation followed by vitrectomy and gas injection followed by face-down positioning is effective in treating this condition.

Our patient was treated with new glasses and observation.

• Donald G. Bockin, OD, can be reached at Central Texas Veterans Health Care System, Temple, Texas; (254) 743-0733; bockin.donald@VA.gov.
• Edited by Leo P. Semes, OD, a professor of optometry, University of Alabama at Birmingham and a member of the Primary Care Optometry News Editorial Board. He may be reached at (205) 934-6773; lsemes@uab.edu.