gunn’s dots with rtx1 - frcrnet · originally described by robert marcus gunn in 1883, gunn’s...

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unn’s dots with RTX1 Pr Michel Paques

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Page 1: Gunn’s dots with RTX1 - FRCRnet · Originally described by Robert Marcus Gunn in 1883, Gunn’s dots are observed in the majority of healthy subjects up to 50 years of age They

Gunn’s dots with RTX1Pr Michel Paques

Page 2: Gunn’s dots with RTX1 - FRCRnet · Originally described by Robert Marcus Gunn in 1883, Gunn’s dots are observed in the majority of healthy subjects up to 50 years of age They

Gunn’s dots

White glistening dots found in normal eyesFirst decribed in 19th centry; few publicationsAttributed to Müller cells without histological demonstration

Page 3: Gunn’s dots with RTX1 - FRCRnet · Originally described by Robert Marcus Gunn in 1883, Gunn’s dots are observed in the majority of healthy subjects up to 50 years of age They

Originally described by Robert Marcus Gunn in 1883, Gunn’s dots are observed

in the majority of healthy subjects up to 50 years of age

They are commonly attributed to Müller cell’s footplates

Despite their potentiel interest, no specific study yet

Page 4: Gunn’s dots with RTX1 - FRCRnet · Originally described by Robert Marcus Gunn in 1883, Gunn’s dots are observed in the majority of healthy subjects up to 50 years of age They

Paques et al. 2014

Gunn’s dots imaging by FIAO

Page 5: Gunn’s dots with RTX1 - FRCRnet · Originally described by Robert Marcus Gunn in 1883, Gunn’s dots are observed in the majority of healthy subjects up to 50 years of age They

Mean diameter 13.5µm ±6 Peak density ~ 200/mm2

Page 6: Gunn’s dots with RTX1 - FRCRnet · Originally described by Robert Marcus Gunn in 1883, Gunn’s dots are observed in the majority of healthy subjects up to 50 years of age They

While their distribution remain stable, the density of Gunn’s dots slowlydecreases over years

Page 7: Gunn’s dots with RTX1 - FRCRnet · Originally described by Robert Marcus Gunn in 1883, Gunn’s dots are observed in the majority of healthy subjects up to 50 years of age They

This suggest that they are flat and very close to the ILM

Gunn’s dots are highly anisotropic; their reflectance parallels that of

the ILM

Page 8: Gunn’s dots with RTX1 - FRCRnet · Originally described by Robert Marcus Gunn in 1883, Gunn’s dots are observed in the majority of healthy subjects up to 50 years of age They

→ This suggests that Gunn’s dots are flat

Page 9: Gunn’s dots with RTX1 - FRCRnet · Originally described by Robert Marcus Gunn in 1883, Gunn’s dots are observed in the majority of healthy subjects up to 50 years of age They

Franze K et al. PNAS 2007;104:8287-8292

Müller cellfootplate

ILM

Vitreous

From the Jastrow electron microscopy atlaswww.uni-

mainz.de/FB/Medizin/Anatomie/workshop/EM/EMHRetinaE.html

Müller cells footplates are much smaller and much more numerous than Gunn’s dots; However, confluence may increase their apparent size

Page 10: Gunn’s dots with RTX1 - FRCRnet · Originally described by Robert Marcus Gunn in 1883, Gunn’s dots are observed in the majority of healthy subjects up to 50 years of age They

Ogawa K. Arch Histol Cytol 2002

Qiao et al. BJO 2005

Guinea pig

Rat

Gunn’s dots are still present over the ILM after PVD, raising doubts

that they could be hyalocytes, furthermore, few histological evidence

of a flattened morphology of hyalocytes. However, it is unclear

wether or not all hyalocytes actually detach from the ILM following

PVD

Page 11: Gunn’s dots with RTX1 - FRCRnet · Originally described by Robert Marcus Gunn in 1883, Gunn’s dots are observed in the majority of healthy subjects up to 50 years of age They

Gunns dots are (probably) not in the retina