Girl reports blurry vision 1 year after normal eye exam

On Nov. 30, 2009, a 9-year-old Caucasian girl presented to the office with blurry vision in both eyes. Her mother reported that the child had an eye examination last year with normal results. She also explained that the eye doctor pulled her into another room without her child to let her know that her daughter was “malingering,” as she “probably wanted glasses.” The mother feels there is something “not right” with her daughter’s eyes. The girl reported that her vision is blurry all day long at distance and near.

The review of systems was unremarkable and the patient’s ocular history was unremarkable. She reported taking 1-mg fluoride tablets, which she chews at night before bed, and taking a children’s daily multivitamin.

Her medical history was unremarkable. Family history was unremarkable, with no vision loss or blindness. The patient is an only child. Both parents had their eyes examined last year and the results were unremarkable. Social history was noncontributory.

Fundus exam showed an irregular foveolar reflex with an egg yolk-like lesion. Images: Caldwell G

OCT showed an intrapigment cyst or cavity in both eyes.

Examination revealed uncorrected visual acuities of 20/25-2 OD and 20/25-2 OS. Refraction unveiled plano -0.25 x 165 OD and plano -0.25 x 180 OS with unchanged visual acuities. Extraocular muscles were full, smooth and unrestricted. Pupils were equally round, reactive to light and free of an afferent pupillary defect. Confrontation fields were normal for both eyes. Slit lamp exam showed epicapsular stars in the right crystalline lens; it was unremarkable in the left eye. Intraocular pressures were 17 mm Hg OD and 16 mm Hg OS at 2:30 p.m.

Fundus examination revealed perfused optic nerve heads that were healthy and distinct with a 0.15 cup-to-disc ratio in the right and left eyes. There was an irregular foveolar reflex with an egg yolk-like lesion, which was just eccentrically located, just temporal to fixation to both eyes. The periphery was unremarkable.

Ocular coherence tomography revealed a central macular thickness of 324 microns OD and 328 microns OS, with intrapigment cyst or cavity in both eyes.

What is your diagnosis?

The intrapigment cyst or cavity in both eyes is quite consistent with Best’s disease. The interesting part of the presentation is that it is slightly eccentric in both eyes and is most likely resulting in the relatively good visual acuities.

I indicated to the parents that Best’s disease has an autosomal dominant inheritance. Furthermore, 50% of those with the genetic abnormality responsible for Best’s disease have a completely normal eye exam, although EOG testing will be completely flat or abnormal.

Fundus exam on May 13, 2010, showed a small Best’s cavity in the right eye and a visible retinal hemorrhage and larger Best’s cavity in the left eye.

Quite naturally, the biggest concern for the family was that their child would have progressive vision loss and go blind. I indicated that while her central vision may decrease, at no time will she ever go totally blind from Best’s disease. I further explained that 75% of the patients who have Best’s disease will have 20/40 or better vision in at least one eye. I also discussed the possibility of a secondary choroidal neovascular membrane, which would be treatable with anti-VEGF injections.

Six-month follow-up

At this point, I recommended a 6-month follow-up and Amsler grid testing. Additionally, we discussed the possibility of genetic testing, as this would certainly confirm the diagnosis. Alternatively, we could do an EOG. They wanted to discuss it amongst themselves and decide how to proceed. Genetic testing and EOG were later declined.

On May 13, 2010, the now 10-year-old girl presented with decreased vision and a distorted Amsler grid in her left eye. Best corrected visual acuities were: 20/20-2 OD and 20/100 OS. External and slit lamp examination did not change.

Dilated fundus examination revealed an unchanged optic nerve, a foveolar light reflex and a retinal pigment epithelium depigmentation just temporal to fixation with a small Best’s cavity in the right eye. The left eye showed a visible retinal hemorrhage and a larger Best’s cavity.

OCT of the right eye revealed 257 micron thickness with a small cavity in the subretinal space consistent with Best’s disease; it remained temporal eccentrically located. OCT of the left eye revealed a central macular thickness of 378 microns with a solid elevation in the subretinal space as well as subretinal fluid consistent with a presumed choroidal neovascular membrane. There was no evidence of intraretinal fluid.

OCT showed a small cavity in the subretinal space in the right eye and a solid elevation in the subretinal space and subretinal fluid consistent with a presumed choroidal neovascular membrane in the left eye.

Follow-up fundus exam after an anti-VEGF injection in the left eye.

It was reported to the girl and her parents that there had been clear progression with most likely a choroidal neovascular membrane. A retinal consult was scheduled for May 17, 2010.

The retinal specialist confirmed Best’s disease with evidence of a choroidal neovascular membrane in the left eye, and anti-VEGF therapy was recommended. After discussing risks, benefits and alternatives of treatment, an uncomplicated anti-VEGF injection was preformed and the patient tolerated the treatment extremely well.

On Feb. 8, the retinal specialist returned the patient to my care for further monitoring. Her visual acuities were 20/20 OD and 20/30 OS.

A rare disease

Best’s disease, also known as Best’s vitelliform macular dystrophy, is a hereditary form of progressive macular dystrophy first identified in 1905. It is a rare disease and is found in individuals of European, Hispanic and African ancestry. There is no gender predilection.

Usual onset of Best’s disease is in patients between 3 years and 15 years old, with an average age of 6 years. The abnormality is in the retinal pigment epithelium, as noted on histopathology and electrophysiology testing. No treatment exists for vitelliform macular dystrophy. Secondary choroidal neovascularization can be managed with direct laser treatment or with an intravitreal injection of bevacizumab, as in this case. Evaluation of family members is recommended to identify carriers and individuals with vitelliform macular dystrophy. Both genetic counseling and career counseling should be considered. When vision loss occurs, a low vision consult is often beneficial.

• Greg Caldwell, OD, FAAO, is in private practice in Duncansville and Johnstown, Pa., as an ocular disease consultant. He can be reached at Centar, Imler, Gjurich and Caldwell, 108 Olde Farm Office Road, Duncansville, PA 16635; (814) 695-3141; grubc@aol.com.
• 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 contacted at 1716 University Blvd., Birmingham, AL 35294-0010; (205) 934-6773; fax: (205) 934-6758; lsemes@uab.edu.