Search results
Results from the WOW.Com Content Network
The Maklakoff tonometer was an early example of this method, while the Goldmann tonometer is the most widely used version in current practice. [3] Because the probe makes contact with the cornea, a topical anesthetic, such as proxymetacaine, is introduced on to the surface of the eye in the form of an eye drop. [citation needed]
Ocular hypertension is the presence of elevated fluid pressure inside the eye (intraocular pressure), usually with no optic nerve damage or visual field loss. [ 1 ] [ 2 ] For most individuals, the normal range of intraocular pressure is between 10 mmHg and 21 mmHg. [ 3 ]
Intraocular pressure (IOP) is the fluid pressure inside the eye. Tonometry is the method eye care professionals use to determine this. IOP is an important aspect in the evaluation of patients at risk of glaucoma. [1] Most tonometers are calibrated to measure pressure in millimeters of mercury .
The Schiotz tonometer consists of a curved footplate which is placed on the cornea of a supine patient. A weighted plunger attached to the footplate sinks into the cornea. A scale then gives a reading depending on how much the plunger sinks into the cornea, and a conversion table converts the scale reading into IOP measured in mmHg.
The examiner will ask the patient to cover one eye and stare at the examiner. Ideally, when the patient covers their right eye, the examiner covers their left eye and vice versa. The examiner will then move his hand out of the patient's visual field and then bring it back in. Commonly the examiner will use a slowly wagging finger or a hat pin ...
There are many diseases known to cause ocular or visual changes. Diabetes , for example, is the leading cause of new cases of blindness in those aged 20–74, with ocular manifestations such as diabetic retinopathy and macular edema affecting up to 80% of those who have had the disease for 15 years or more.
A distant object is defined as an object located beyond 6 meters (20 feet) from the eye. [citation needed] When an object is located close to the eye, the rays of light from this object no longer approach the eye parallel to each other. Consequently, the eye must increase its refractive power to bring those rays of light together on the retina.
In patients with headaches, the finding of swollen optic discs (papilledema) on ophthalmoscopy is a key sign indicating raised intracranial pressure, which may be due to conditions such as hydrocephalus, benign intracranial hypertension (pseudotumor cerebri), and brain tumors. In glaucoma, cupped optic discs are seen.