title: Differences in ocular findings in two siblings: one with complete and other with incomplete achromatopsia.
abstract: Patients with complete achromatopsia (ACHM) lack cone function, and patients with incomplete ACHM have relatively good visual acuity with residual color vision. The pathological mechanism(s) underlying incomplete ACHM has not been determined. The purpose of this study was to determine the pathophysiology of ACHM in two siblings: one with complete ACHM and the other with incomplete ACHM.
  
  
  
  The medical charts of the two siblings were reviewed.
  
  
  
  The sibling with incomplete ACHM had decimal visual acuities that ranged from 0.4 to 0.6 and had moderate color blindness in both eyes. Her younger brother was diagnosed with complete ACHM and was not able to hold fixation, had severe pendular nystagmus, visual acuity that ranged from 0.08 to 0.1, and severe color vision abnormalities in both eyes. Optical coherence tomography (OCT) showed that the ellipsoid zone (EZ) was disruptive in the macular region in both patients. However, careful examination of the OCT images in the incomplete ACHM patient showed a high-density EZ in the central fovea. Adaptive optics (AO) fundus imaging of the sibling with incomplete ACHM revealed sparse cone mosaics remaining within 1° of the foveal center with no mosaics visible outside the central fovea. AO fundus imaging could not be performed in Case 2 because of the severe nystagmus.
  
  
  
  Our results showed that cone mosaics were present in the central fovea in the sibling with incomplete ACHM patient. This may explain the better visual acuity and color vision in this sibling.
authors.affiliation: Department of Ophthalmology, Graduate School of Medicine, Nagoya University, 65 Tsuruma-cho, Showa-ku, Nagoya, 466-8550, Japan. ueno@med.nagoya-u.ac.jp.
authors.forename: Shinji
authors.initials: S
authors.lastname: Ueno
authors.affiliation: Department of Ophthalmology, Graduate School of Medicine, Nagoya University, 65 Tsuruma-cho, Showa-ku, Nagoya, 466-8550, Japan.
authors.forename: Ayami
authors.initials: A
authors.lastname: Nakanishi
authors.affiliation: Department of Ophthalmology, Graduate School of Medicine, Nagoya University, 65 Tsuruma-cho, Showa-ku, Nagoya, 466-8550, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Sayo
authors.affiliation: Department of Ophthalmology, Graduate School of Medicine, Nagoya University, 65 Tsuruma-cho, Showa-ku, Nagoya, 466-8550, Japan.
authors.forename: Taro
authors.initials: T
authors.lastname: Kominami
authors.affiliation: Department of Ophthalmology, Graduate School of Medicine, Nagoya University, 65 Tsuruma-cho, Showa-ku, Nagoya, 466-8550, Japan.
authors.forename: Yasuki
authors.initials: Y
authors.lastname: Ito
authors.affiliation: Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Takaaki
authors.initials: T
authors.lastname: Hayashi
authors.affiliation: National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan.
authors.forename: Kazushige
authors.initials: K
authors.lastname: Tsunoda
authors.affiliation: National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Iwata
authors.affiliation: Department of Ophthalmology, Graduate School of Medicine, Nagoya University, 65 Tsuruma-cho, Showa-ku, Nagoya, 466-8550, Japan.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Terasaki
mesh_terms: D002648:Child; D055253:Color Vision / Q000502:physiology*; D003117:Color Vision Defects / Q000503:physiopathology*; D004596:Electroretinography; D005260:Female; D005584:Fovea Centralis / Q000503:physiopathology; D005654:Fundus Oculi; D006801:Humans; D008297:Male; D010641:Phenotype; D017949:Retinal Cone Photoreceptor Cells / Q000502:physiology; D035781:Siblings; D041623:Tomography, Optical Coherence / Q000379:methods; D014792:Visual Acuity / Q000502:physiology
keywords: Achromatopsia; Adaptive optics (AO) fundus image; Cone mosaic; Incomplete achromatopsia; Optical coherence tomography