Case of the Month
Edited by Robert N. Johnson, MD
Case #107, May, 2018
Presented by Judy Chen, MD
A 32-year-old Hispanic man with blurred vision in both eyes.
Figures. 1A and B: Fundus photograph of the right (A) and left (B) eyes showing blunting of the foveal reflex and mild retinal pigment epithelial mottling in the central macula.
Figures. 2A and B. Fundus autofluorescence imaging of the right (A) and left (B) eyes were remarkable for generalized hypoautofluorescence of the central macula without a distinct foveal center
A 32-year-old Hispanic man presented for routine eye examination. He states that his vision was ‘poor’ since childhood and was notable for strabismus and hyperopia, for which he wore +6.50D and +7.00D contact lenses in the right and left eyes, respectively. Several years earlier, he had been evaluated elsewhere and thought to possibly have albinism. His past medical history and family history were unremarkable. He took Truvada daily for HIV pre-exposure prophylaxis and had recently tested negative for HIV. Social history and review of systems was noncontributory.
On examination, best-corrected visual acuity was 20/40 on the right and 20/25 on the left. Intraocular pressures were normal. Anterior segment examination was unremarkable, with normal iris pigmentation, no iris transillumination defects and clear crystalline lenses. Posterior segment examination revealed blunting of the foveal reflex and mild retinal pigment epithelial mottling in the central macula of both eyes (Figure 1 A & B). Fundus autofluorescence imaging of both eyes were remarkable for generalized hypoautofluorescence of the central macula without a distinct foveal center (Figure 2 A & B). Spectral domain-optical coherence tomography (SD-OCT) through the central fovea and optic nerve of each eye showed complete loss of the foveal depression and slight widening of the outer nuclear layer (ONL) centrally (Figure 3 A & B). Optical coherence tomography angiography (OCT-A) depicted total absence of the foveal avascular zone (Figure 4 A & B).
Figures 3A and B:. Twelve millimeter long scan spectral domain-optical coherence tomography (SD-OCT) of the right (A) and left (B) eyes through the central fovea and optic nerve of each eye showed complete loss of the foveal depression and slight widening of the outer nuclear layer (ONL) centrally.
Figures 4A and B: Six millimeter optical coherence tomography angiography (OCTA) studies of the superficial vascularature of the right (A) and left (B) eyes were significant for total absence of the foveal avascular zone in both eyes.
What is your Diagnosis?
Idiopathic fovea plana, foveal hypoplasia associated with ocular albinism, aniridia, nanophthalmos, incontinentia pigmenti, early retinal degeneration, retinopathy of prematurity, or syndrome of autosomal dominant foveal hypoplasia and presenile cataracts.
The term fovea plana was first coined by Marmor et al in 2008,1 when they described four patients who maintained good vision between 20/20 and 20/50 despite their lack of foveal pits on OCT. They observed that these patients had normal cone diameters on adaptive optics imaging and normal central multifocal electroretinogram responses despite the abnormal architecture, concluding that the foveal pit is not required for foveal cone specialization anatomically or functionally. Due to the negative visual connotations of the term foveal hypoplasia, Marmor et al1 proposed the term fovea plana to describe the anatomic absence of a foveal pit.
Thomas et al2 examined the OCT imaging of 69 patients with foveal hypoplasia and proposed a grading system based on 3 features of normal foveal development: 1) displacement of cells from the inner retinal layers towards the periphery (displacement of plexiform layers and deepening of the foveal pit), 2) migration of cone photoreceptors into the fovea center (represented on OCT by outer nuclear layer widening) and 3) specialization of cone photoreceptors (represented on OCT by outer segment lengthening). These features were then organized into a grading system with Grade 1 being the mildest disease associated with better visual acuity and Grade 4 as the most severe with worse visual acuity. They concluded that the higher grades were associated with worse vision because foveal development was arrested at an earlier stage.
The introduction of OCT-A has allowed for a more in-depth study of the anatomic features of fovea plana. Kaidonis et al3 observed a correlation between the level of organization of the superficial and deep capillary plexi on OCT-A to the grade and severity of vision loss in the patients; namely, those with more orderly vascular patterns had better vision. In addition, Dolz-Marco et al4 recently reported that in addition to the absence of a foveal avascular zone, OCT-A also demonstrated preserved fusion of both the superficial and deep capillary plexuses around the foveal center – a novel observation that would not have been detectable on fluorescein angiography.
Take Home Points
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