Playlist • Ophthalmology 05 Glauc...
Early glaucomatous changes should be suspected to exist if fundus examination reveals one or more of the following signs:
1. Vertically oval cup due to selective loss of neural rim tissue in the inferior and superior poles.
2. Asymmetry of the cups. A difference of more than 0.2 between two eyes is significant.
3. Large cup, i.e., 0.6 or more (normal cup size is 0.3 to 0.4) may occur due to concentric expansion.
4. Splinter haemorrhages present on or near the optic disc margin.
5. Pallor areas on the disc.
6. Atrophy of retinal nerve fibre layer which may be
seen with red free light.
LATE
Marked cupping (cup size 0.7 to 0.9), excavation may even reach the disc margin, the sides are steep and not shelving (c.f. deep physiological cup) which are well-delineated on OCT examination
Thinning of neuroretinal rim which occurs in advanced cases is seen as a crescentric shadow adjacent to the disc margin. Normally, the thickest to thinnest parts of the neuroretinal rim of the optic disc are inferior, superior, nasal and temporal (ISNT rule). Any variation from this helps to detect glaucoma. Notching of the rim specially up to disc margin is pathognomic.
Nasal shifting of retinal vessels which have the appearance of being broken off at the margin is an important sign (Bayonetting sign). When the edges overhang, the course of the vessels as they climb the sides of the cup is hidden.
Pulsations of the retinal arterioles may be seen at the disc margin (a pathognomic sign of glaucoma), when IOP is very high.
Lamellar dot sign the pores in the lamina cribrosa are slit-shaped and are visible up to the margin of the disc.
3 окт 2024
