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Patient experiences bilateral, painless loss of vision
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A 36-year-old white female presented for an urgent care appointment complaining of a painless loss of vision. Specifically, she had noticed a constant, localized “dark spot” in her central vision located just to the right of her line of sight for a few days. The patient denied any history of trauma and reported no significant personal or family ocular history or medical history. Her only medication was calcium supplements.
Uncorrected entering acuity measured 20/20 OD and 20/25 OS, which was correctable to 20/20. Pupils were equal, round and reactive, without afferent defect. Ocular motility was smooth and full. Intraocular pressure measured 17 mm Hg OU at 1:20 p.m. Slit lamp examination was unremarkable, and dilated fundus examination revealed the presence of faint, yellow retinal opacities in the paramacular area of both eyes. Threshold visual field testing using the 30-2 SITA STD testing strategy revealed bilateral central scotomas. Return testing using a 10-2 SITA STD testing strategy revealed the field loss was actually a ring scotoma.
These were all new findings, as the patient’s medical record showed previous retinal examination, and visual field testing was normal.
Dilated fundus examination revealed the presence of faint, yellow retinal opacities in the
paramacular area of both eyes.
Images: Nixon GJ
Conditions to consider within the differential diagnosis of acquired posterior pole deposits in adult patients should include fundus albipunctatus, punctate inner choroidopathy, cone dystrophy, Stargardt’s disease and age-related macular degeneration.
Differential diagnoses
Fundus albipunctatus presents with numerous diffuse, small, discrete, white dots throughout the posterior pole and retinal midperiphery but spares the macula. In addition, it does not affect acuity or visual field, as seen in our patient.
Punctate inner choroidopathy (PIC) is an uncommon idiopathic condition that typically presents in women in the third to fourth decade with blurred vision and central scotomas. PIC begins with the formation of randomly scattered yellow creamy lesions with fuzzy borders at the level of the choroid that resolve after a few weeks, leaving well demarcated atrophic scars in the retinal pigment epithelium (RPE). While both eyes are often eventually involved, they typically do not present at the same time. Even when both eyes are affected, the lesions do not display good symmetry between the eyes, as is seen in our patient.
Cone dystrophy presents in the second to fourth decade of life with gradual impairment of central vision. Unlike our patient, the reduction in vision affects acuity and color perception more than the visual field, and the decline of vision typically precedes any physical retinal findings. However, a bull’s eye macular appearance often develops as the decrease in visual acuity continues.
Threshold visual field testing using the 30-2 SITA STD testing strategy revealed bilateral central scotomas.
Stargardt’s disease (also known as fundus flavimaculatus and juvenile macular degeneration) is an autosomal recessive condition that most often develops in late childhood or adolescence but may not show signs until between the ages of 30 and 40. It is characterized by yellow or white deposits at the level of the RPE that surround the macula within the posterior pole. These lesions often take on irregular shaped fish-tail like configuration. Degeneration of the RPE can cause pigment clumping, giving the macula a “beaten-metal” appearance, and atrophy of the RPE surrounding the macula can result in a bull’s-eye appearance. These patients often exhibit a central scotoma along with a slow and gradual decline in acuity until they reach the level of 20/40, then can rapidly decline to 20/200.
Diagnostic testing
Electrodiagnostic testing can show great variability in many of these conditions, so fluorescein angiography can be of great diagnostic value to investigate the potential etiology of these types of retinal deposits. The angiography results of this patient’s left eye display mottled hyperfluorescence surrounding the macula in an early bull’s-eye pattern. Another feature of the angiogram is a markedly darkened choroidal appearance in all phases of the exam. This is consistent with the “dark choroid” or “silent choroid” appearance that is common in Stargardt’s disease. This Stargardt angiography feature is the result of lipofuscin accumulation within the RPE, which absorbs the choroidal fluorescence throughout the exam. Additionally, optical coherence tomography can be useful to detect early lipofuscin accumulation in the RPE and corresponding disruption to the photoreceptor layer.
This patient’s management
The characteristics of how this patient presented with bilateral paramacular retinal deposits with simultaneous reduced acuity and central scotoma along with the results of the fluorescein angiography confirmed the diagnosis of Stargardt’s disease. There are no universally accepted treatments for this condition. However, management typically includes providing the best refractive correction with good UV blocking as well as tinted lenses for outdoor use.
Return testing using a 10-2 SITA STD testing strategy revealed the field loss was actually a
ring scotoma.
Angiography results of the patient’s left eye show mottled hyperfluorescence surrounding the
macula in an early bull’s-eye pattern.
Additionally, this patient’s retinal specialist recommended the use of Age-Related Eye Disease Study formula vitamins as a measure to support and sustain RPE health. However, vision loss is eventually inevitable for patients with Stargardt’s disease and requires regular monitoring of the visual acuity and visual field with a testing pattern such as a central 10-2.
Current 10-2 threshold shows progression of central field loss.
I have been following this patient for more than 8 years since her diagnosis. At her most recent visit, her acuity had declined to 20/70 OD and 20/30 OS, with progression of central field loss. As is often the case, this most recent decline in visual quality provoked a consultation with a vision rehabilitation specialist to investigate visual aids to assist her activities of daily living.