Purpose-We aimed to characterize and grade the spectrum of foveal hypoplasia based on different stages of arrested development of the fovea. Grading was performed using morphological findings obtained by ultrahigh resolution spectral domain optical coherence tomography (UHR-OCT). Best corrected visual acuity (BCVA) was calculated for different grades. Design-Observational Case SeriesParticipants and Controls-Sixty-nine patients with foveal hypoplasia (albinism (n=34), PAX6 mutations (n=10), isolated cases (n=14), achromatopsia (n=11)) and 65 control subjects were examined.Methods-A 7x7mm retinal area was sampled using a 3-dimensional scanning protocol (743x75; AxB scans) with UHR-OCT (SOCT Copernicus HR, 3μm axial resolution). Gross morphological abnormalities were documented. B-scans at the fovea were segmented using a longitudinal reflectivity profile. Logarithm of Minimum Angle of Resolution (LogMAR) BCVA was obtained.Main Outcome Measures-Grading was based on presence or absence of foveal pit, widening of outer nuclear layer (ONL) and outer segment (OS) at the fovea. Quantitative measurements were performed for comparing atypical foveal hypoplasia in achromatopsia. BCVA was compared to the grade of foveal hypoplasia Results-Four grades of foveal hypoplasia were distinguished grade 1: shallow foveal pit, presence of ONL widening, presence of OS lengthening; grade 2: grade 1 but absence of foveal pit, grade 3: grade 2 but absence of OS lengthening; grade 4: grade 3 but absence of ONL widening). There was significant difference in visual acuity (VA) associated with each grade (p<0.0001). Grade 1 was associated with the best VA (median VA = 0.2), while grade 2, 3 and 4 was associated with progressively poorer VA with a median VA of 0. 44, 0.60 and 0.78 Correspondence and address for reprints: Professor Irene Gottlob (ig15@le.ac.uk) HHMI Author ManuscriptHHMI Author Manuscript HHMI Author Manuscript respectively. The atypical features seen with foveal hypoplasia associated with achromatopsia were characterized by decreased retinal (RT) and ONL thickness and deeper foveal depth (FD).Conclusions-We have developed a structural grading system for foveal hypoplasia based on the stage at which foveal development was arrested, which helps to provide a prognostic indicator for VA and is applicable in a range of disorders associated with foveal hypoplasia. Atypical foveal hypoplasia in achromatopsia shows different characteristics.Normal foveal development occurs in stages where the pit formation for the incipient fovea starts at fetal week 25 and the excavation is complete 15-45 months after birth. 1 Disruption of this developmental process leads to foveal hypoplasia which is a characteristic morphological abnormality associated with conditions such as albinism, PAX6 mutations or it may occur in isolation. [2][3][4][5] With the advent of optical coherence tomography (OCT) it is now possible to document the varying degrees of foveal hypoplasia which are likely to represent the different stages of arrested deve...

Idiopathic congenital nystagmus is characterized by involuntary, periodic, predominantly horizontal oscillations of both eyes. We identified 22 mutations in FRMD7 in 26 families with X-linked idiopathic congenital nystagmus. Screening of 42 singleton cases of idiopathic congenital nystagmus (28 male, 14 females) yielded three mutations (7%). We found restricted expression of FRMD7 in human embryonic brain and developing neural retina, suggesting a specific role in the control of eye movement and gaze stability.

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The findings suggest that nystagmus is more common in the general population than previously thought. This may be of significance in resource allocation and health care planning.

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