RETINA QUIZ

Was There More than Abrasion
To this 'Cloudy' Vision?

by Mark T. Dunbar, O.D

A 55-year-old white female from the Florida Keys was polishing her boat when she got rubbing compound in her eye. She noted blurry vision after she began cleaning her eye. Her optometrist who fit her with contact lenses told her of a possible corneal abrasion. She discontinued lens wear but continued to notice blurry vision in that eye.

On referral to a retinal specialist four days after the initial incident, she described her right eye as having a "cloud" in her central vision. Her medical history was unremarkable, with her only medication being a daily hormone supplement.

Note the "whitening" superior to the macula O.D., and flamed hemorrhages in both eyes.

Best corrected visual acuity was 20/40 O.D. and 20/20 O.S. Amsler grid testing showed a small inferior relative scotoma that barely extended into central fixation in the right eye. The left eye was normal. Her anterior segment was unremarkable O.U. Dilated fundus exam showed an edematous area of retinal "whitening" superior to the macula in the right eye. The fundus photos below show the other significant findings seen in both eyes.

Quiz
1) Which test provided the most useful information to the retinal specialist?
a) Blood pressure.
b) Threshold visual field.
c) Fluorescein angiography.
d) Blood sugar finger stick.

2) What is the cause of the decreased vision in the right eye?
a) Choroidal neovascular membrane from AMD.
b) Idiopathic central serous choroidopathy (ICSC).
c) Nonproliferative diabetic retinopathy with macular edema.
d) Small branch retinal artery occlusion.

3) How would you best characterize the other significant retinal findings present in both eyes?
a) Microvascular changes from diabetic retinopathy.
b) Microvascular changes from hypertensive retinopathy.
c) Age-related degenerative changes.
d) Chronic RPE disease associated with stress.

4) What is the best management for this patient?
a) Observation only.
b) Laser the choroidal neovascular membrane.
c) Immediate referral for evaluation and management of any systemic conditions.
d) Carotid Doppler studies.

Discussion
This patient has a small branch retinal artery obstruction that involves the macula in the right eye. The edematous area of retinal whitening is the result of ischemia from closure of the artery that runs superior to the macula. Typically branch or central retinal artery occlusions result from an embolic process. Because of her age and other significant findings, this was not thought to be the case with this patient.

Besides the small retinal artery obstruction, there were other microvascular changes present in both eyes including cotton-wool spots, flamed hemorrhages, crossing changes and attenuation of the arteries and veins. These finding alone should make you suspicious that the patient has chronic, poorly controlled hypertension.

The patient reported that her blood pressure was normal as far she knew, but admitted that she had not had a general physical in several years. While she was seated in the exam chair her blood pressure was found to be 260/160. A fluorescein angiogram was performed in addition to a CBC and the patient was sent immediately to the emergency room for management of her hypertension.

She returned a month later with improvement in her visual acuity to 20/20, resolution in the area of retinal ischemia and reperfusion of the small retinal artery. She was, however, still bothered by a small relative paracentral scotoma that was slightly inferior to fixation. She was taking medication for her blood pressure, but stated that her doctor was having difficulty getting adequate control of the blood pressure. Carotid Doppler studies were also performed and were negative.

Hypertension affects an estimated 58 million adults in the United States.1 Chronic elevated blood pressure results in focal and generalized constriction of the retinal arterioles mediated by autoregulation. This can commonly lead to the development of retinal hemorrhages, cotton-wool spots, intraretinal lipid and, in severe cases, disc swelling with macular star formation. Chronic hypertension can also lead to arteriolosclerosis and atherosclerosis of the retinal and choroidal vessels. In severe uncontrolled hypertension, closure of the retinal capillaries can occur in addition to retinal arterial and venous occlusion.

In this patient, an area of occlusion is evident adjacent to the optic nerve as a small branch of the superior temporal artery crosses over the vein. Following the artery temporally, a small patch appears sclerosed and nonpatent. The artery reperfuses again farther temporally. This is likely the result of either vasospasm from autoregulation, or a change due to atherosclerosis. Atherosclerosis refers to changes that occur in the intima of the blood vessels. This occurs mostly in the peripapillary retinal arteries and in the ciliary and choroidal arteries.2 Lipid deposition in the artery intima often leads to calcification and fibrosis, compromising the lumen and predisposing the artery to thrombosis.1

Cases of acute hypertension can severely affect the choroid, resulting in choriocapillaris occlusion and breakdown of the outer blood-retina barrier. No choroidal involvement was seen in this patient, probably because she had chronically elevated high blood pressure and her regulatory processes prevented this from occurring. These same regulatory processes also prevented the development of more serious consequences from her dangerously uncontrolled high blood pressure, such as a stroke or even death.

This patient was lucky that her undiagnosed high blood pressure was discovered before she developed more serious consequences. This case highlights the value and importance of a simple in-office test such as checking the blood pressure.

1. Murphy RP, Chew EY. Hypertension. In: Ryan SJ, ed. Retina, Second edition, St. Louis: Mosby, 1994:1413-1419.
2. Green WR. Systemic disease with retinal involvement. In: Spencer WH, ed. Ophthalmic Pathology: An Atlas and Textbook. Philadelphia: WB Saunders Co., 1985:1034-1047.

Answers: 1. a; 2. d; 3. b; 4. c.