Two siblings with late-onset cone–rod dystrophy and no visible macular degeneration

Hiroyuki Sakuramoto,¹ Kazuki Kuniyoshi,¹ Kazushige Tsunoda,² Masakazu Akahori,² Takeshi Iwata,² Yoshikazu Shimomura<sup>1

1</sup>Department of Ophthalmology, Kinki University Faculty of Medicine, Osaka-Sayama City, Osaka, Japan; ²National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan

Background: We report our findings in two siblings with late-onset cone–rod dystrophy (CRD) with no visible macular degeneration.
Cases and methods: Case 1 was an 82-year-old man who first noticed a decrease in vision and color blindness in his early seventies. His mother and younger sister also had visual disturbances. His decimal visual acuity was 0.3 in the right eye and 0.2 in the left eye. Ophthalmoscopy showed normal fundi, and fluorescein angiography was also normal in both eyes. The photopic single flash and flicker eletroretinograms (ERGs) were severely attenuated and the scotopic ERGs were slightly reduced in both eyes. Case 2 was the 80-year-old younger sister of Case 1. She first noticed a decline in vision and photophobia in both eyes in her early seventies. Her decimal visual acuity was 0.4 in the right eye and 0.2 in the left eye. Ophthalmoscopy showed mottling of the retinal pigment epithelium in the midperiphery with no visible macular degeneration. The photopic single flash and flicker ERGs were severely attenuated, and the scotopic ERGs were slightly reduced in both eyes.
Conclusion: These siblings are the oldest reported cases of CRD with no visible macular degeneration. Thus, CRD should be considered in patients with reduced visual acuity, color blindness, and photophobia even if they are older than 70 years.

Keywords: cone–rod dystrophy, peripheral cone dystrophy, occult macular dystrophy, late onset, macular degeneration, negative ERG