What is the average cup-to-disc ratio?
What is the average cup-to-disc ratio?
The normal cup-to-disc ratio is less than 0.5. A large cup-to-disc ratio may imply glaucoma or other pathology. However, cupping by itself is not indicative of glaucoma. Rather, it is an increase in cupping as the patient ages that is an indicator for glaucoma.
What is normal optic disc cupping?
A C/D ratio between 0.4 and 0.8 can characterize a patient with a normal optic disc (i.e., physiologic cupping), a glaucoma suspect or someone with early to moderate glaucoma (depending on the optic disc size); If the C/D ratio is 0.8 or greater, consider the individual’s disc as glaucomatous unless proven otherwise.
Does cup-to-disc ratio change?
Using linear regression the rate of linear cup-to-disc ratio change was 0.0068 +/- 0.0062 per year (range -0.0025- 0.0269). Three eyes had an increase in the peripapillary atrophy area.
Does cup-to-disc ratio increase with age?
Vertical optic cup diameter and optic cup area increased with age. The mean cup/disc diameter ratio increased by about 0.1 between the ages of 30 and 70 years.
What is normal optic disc size?
Measuring optic disk size is an essential part of the optic nerve head for evaluation for glaucoma. The average human optic disc dimensions are 1.88mm vertically by 1.77mm horizontally, and can be grouped by vertical diameter into small (1.2-1.7mm), average (1.87-1.96mm), and large (2.03-2.27mm) disc sizes [1].
What does a small cup-to-disc ratio mean?
Background: A small cup-to-disc (C:D) ratio is an established risk factor for nonarteritic anterior ischemic optic neuropathy. We sought to determine if a small C:D. ratio was present in patients with idiopathic intracranial hypertension (IIH) as a potential risk factor for visual loss in that disorder.
What is CDR in glaucoma?
The Cup-to-Disc Ratio (CDR) serves as the most important indicator for glaucoma screening and plays a significant role in clinical screening and early diagnosis of glaucoma. In general, obtaining CDR is subjected to measuring on manually or automatically segmented optic disc and cup.
What is cup-to-disc ratio in glaucoma?
The C/D ratio represents the depression in the optic disc in which neural tissue is absent and is compared to the overall optic disc size. Eyes that have glaucoma may have a small or large C/D ratio. Also, a larger C/D ratio has a greater risk for developing glaucoma. Large disc: This disc obeys the ISNT rule.
Does optic nerve cupping always mean glaucoma?
Up to 20% of nonglaucomatous cupping has been misdiagnosed and treated as glaucoma. Young age, pallor of the disc, loss of visual acuity and color vision, and a poor correlation between optic nerve and visual field findings are suggestive of a condition other than glaucoma.
What does cupping mean in an eye exam?
The cupping of the optic nerve means the size of the depression in the middle of the nerve when viewed from the front of the eye. When there is damage to the optic nerve, the cupping increases.
What does a small cup to disc ratio mean?