Retina Quiz
Trying to Save One Good Eye
Mark T. Dunbar, O.D.A 26-year-old engineer presented for an evaluation of her left eye. She reported reduced acuity in the right eye after having several laser treatments 2 years ago. She is nearsighted with no visual complaints in her left eye. The patient presented for evaluation because this is her only good eye.
 |
 |
| This 26-year-old female has a disciform scar in the macula of the right eye as a result of laser treatment. Note the other obvious fundus changes present in both eyes. | |
Best-corrected visual acuity was 20/200 O.D. and 20/20 O.S. with
a -4.00D myopic correction in each eye. Confrontation fields were full
to careful finger counting. The pupils were round and reactive with no
afferent defect. Amsler grid showed a dense central scotoma in the right
eye; the left eye was normal. The anterior segments were unremarkable.
A dilated fundus exam showed a small cup with good rim coloration and perfusion
O.U. The vitreous was clear in both eyes. In the macula of the right eye
there was an obvious chorioretinal scar. Other fundus findings are evident
in the photographs.
Take the Retina Quiz1. What complication did the patient develop in the right eye?a. Choroidal neovascularization. b. Macular hole. c. Choroidal rupture. d. Globe perforation. 2. What obvious fundus findings are present in both eyes?
3. Which condition hasn’t been linked with these fundus changes?
4. Given the obvious fundus changes in this patient, what is the most
likely underlying condition?
|
Discussion
From the fundus photos it’s clear that this patient has prominent angioid streaks in both eyes. Angioid streaks are radiating, jagged, tapering lines extending from the peripapillary area into the peripheral fundus. They’re caused by a linear, crack-like dehiscence in the collagenous and elastic portion of Bruch’s membrane. They can have a subtle appearance, so it’s easy to mistake them for normal choroidal or retinal vessels. The color can vary from reddish-orange to dark-red or brown, depending on the pigmentary characteristics of the underlying choroid as it becomes more visible over a thinned RPE.Choroidal neovascularization may grow through the breaks in Bruch’s membrane and result in visual loss. These are type-I membranes, growing below the RPE. Because of the brittle nature of Bruch’s membrane in those with angioid streaks, patients may also suffer visual loss from choroidal rupture and submacular hemorrhage following minor trauma.
It makes sense that our patient developed a choroidal neovascular membrane in the macula secondary to the angioid streaks. She subsequently had laser treatment and is now left with a rather large disciform scar and 20/200 acuity in the left eye. The obvious question is, What’s the underlying etiology of the angioid streaks? Remember the list of differential diagnoses for angioid streaks: pseudoxanthoma elasticum (PXE), sickle cell disease, Paget’s disease, Ehlers-Danlos syndrome and idiopathic.
After careful examination it was clear that our patient had PXE, also known as Grönblad-Stranberg syndrome. In 1929 the Swedish ophthalmologist Ester Grönblad and the dermatologist J.V. Strandberg separately reported on a patient who had both the skin changes of PXE and retinal angioid streaks.1 The two manifestations became linked to their name.
In our patient, not only were the fundus findings pathognomonic, she also had skin changes characteristic of PXE. In the flexural surface area in the back of her neck there were confluent yellowish papules giving the skin a “plucked-chicken” appearance. There were similar skin changes along the antecubital fossa.
PXE is a systemic disease in which the primary defect appears to be production of abnormal elastic fibers with secondary calcification. Changes with PXE can occur in the skin, cardiovascular system, gastrointestinal system and the eyes. In addition to the angioid streaks, other associated funduscopic findings include peau d’orange pigmentary changes in the RPE, a mottled appearance resembling an orange peel. These are more prominent in childhood, before angioid streaks develop. In our patient peau d’orange changes were apparent in the midperiphery.
Our patient also had focal atrophic pigment epithelial lesions characteristic of PXE. These appear as multiple small, round, yellow or slightly pink RPE atrophic lesions. Sometimes they appear as punched-out scars resembling histo-spots. She also had several small subretinal crystalline bodies in the mid-peripheral fundus. These also can be seen in the juxtapapillary area, especially inferiorly in PXE patients.
How should you manage a patient whom you suspect has PXE? If the diagnosis hasn’t been established, refer the patient to a dermatologist for possible skin biopsy. Also, their primary care physician should evaluate them for gastrointestinal disease. A survey at the Mayo Clinic in 1961 found that 10 of 74 patients with PXE had gastrointestinal bleeding.2 Patients with PXE can also have cardiac manifestations including arterial calcification, premature coronary atherosclerosis, angina and early myocardial infarctions.
Our patient already carried the diagnosis of PXE when she presented. Obviously she is at risk of developing a CNVM in her left eye. We gave her a home Amsler grid with instructions on its use, and told her to wear protective eyewear.
- 1. Grönblad E. Angioid streaks-pseudoxanthoma elasticum. Acta Ophthalmol (KbH) 1929;7:329.
- 2. Connor PJ, Juergens JL, Perry HO, et al. PXE and angioid streaks. A review of 106 cases. Am J Med 1961;30:537.
April 15, 2000