What is the examination of fundus oculi | Diseases and conditions: Medical tests.

Dilated eye exam

Funduscopia, ophthalmoscopy or dilated eye exam is a medical technique that allows to visualize the inside of the eye to make a diagnosis. So dilates the pupil with drugs that are deposited in the form of drops on the surface of the eye; so, the ophthalmologist can see easily the interior of the eyeball with an instrument called ophthalmoscope.
The ophthalmoscope invented in 1850 the medical and German physicist Hermann von Helmholtz. It consists of an apparatus comprising a series of mirrors and crystals that illuminate the retina of the eye without that light is reflected. If it were not for the ophthalmoscope light flashes it would and could not see the bottom of eye well, something like what happens when a camera flash remove red eyes. Today two types of ophtalmological equipment have been developed:
Direct ophthalmoscope: is the first that is designed and the easier of the two. The doctor can only see one eye at the same time. The technique requires some skill, but it is used many times in the day to day by ophthalmologists and other doctors.
Indirect ophthalmoscope: is more complex than the previous one; with it, the ophthalmologist can see both eyes of the patient at the same time.
Sometimes it is not enough to use a simple ophthalmoscope and other devices that help examine the fundus oculi are needed. The most widely used is the slit-lamp, a complicated magnifying glass with light in which the patient supports the Chin and forehead so the doctor explore their eyes. Other new techniques would be digital fundus photographs (that allow to compare the evolution of the retina) or the fluorescein angiography (which directly studying the blood vessels).

When doing an examination of fundus oculi

The eye examination serves to diagnose a disease or observe their evolution towards improvement or worsening. It is not the intermediate towards any treatment step. Diseases in which it is intended to perform a dilated eye exam are:
  • Diabetes mellitus: diabetes is the leading cause of blindness in the working population in developed countries, and thanks to the fundus examination we can observe directly the small blood vessels that supply the retina.
  • High blood pressure: in the same way that we can observe in diabetes, alterations of blood vessels that occur in high blood pressure. It also serves to identify the degree of evolution of the disease.
  • Retinal embolism: is used to confirm the presence of a plunger in a retinal artery that blocks the passage of blood into a particular area. A spot in the retina appears red cherry.
  • Venous thrombosis: we can see if the blood flow is correct through you the veins or is interrupted by thrombi. See pictures of flares by across the retina.
  • Retinal detachment: eye fundus examination allows you to see if there is any area of the retina that has lifted from the inside of the eye; If so, would be falling like a curtain.
  • Retinitis pigmentosa: is one of the tests in this genetic disease. Be observed spicules, an aspect similar to the bone, in the periphery of the retina.
  • Posterior Uveitis: cottony buildup ahead of the retina, which are the result of local infection are observed.
  • Macular degeneration: is the cause of most frequent blindness among the elderly. You can see changes in the central area of the retina, called the macula. Sometimes you can see edema clearly.
  • Chronic glaucoma: in this disease the optic nerve erodes little by little in its final part, the optic nerve head. The eye examination can serve to see that damage to the naked eye, but today there are more reliable techniques.
  • Optical neuritis: optic nerve can become inflamed as a result of a viral infection, and thus appears in a dilated eye exam.
  • Ischemic neuropathy: blood flow also can be interrupted at the optic nerve, as a result of diabetes, hypertension or autoimmune diseases.
  • Multiple sclerosis: this neurological disease is common vision is disturbed by the optic nerve involvement. A dilated eye exam should always be done to rule out other causes.
  • Intracranial hypertension: pressure inside the skull increases cause edema of papilla (papilledema). The reasons are varied, they include meningitis, hydrocephalus, brain tumors, bleeding, etc. Examination of fundus oculi, moreover, is a forced test before performing a lumbar puncture, since the existence of papilledema is an absolute contraindication.

Preparation for the examination of fundus oculi

If you will perform a dilated eye exam, these are the issues that you must take into account:
Duration: examination of fundus oculi itself lasts a short time, just a few minutes. However, the dilation of the pupil can take up to an hour, time in which you'll be waiting in a waiting room until the expansion is adequate.
Entry: eye fundus examination is performed on an outpatient basis. It is not necessary to enter for this test.
Is necessary to be accompanied?: Yes, it is recommended to carry a passenger. After hard pupil dilation test several hours, in which the vision will be altered, and is not recommended driving. If only attending the meeting, you must go and return to the hospital in public transport.
Drugs: is not necessary to take any prior medication. Medicines that you are taking very seldom can affect this test. Only communicates to the doctor if you are throwing you eye drops.
Food: it is not necessary to keep fasting.
Clothing: can go to the appointment with any type of clothing. Sunglasses, is recommended since leaving pupils will be very dilated and light of the Sun will be especially annoying.
Documents: don't need to take any special documentation.
Contraindications: a relative contraindication is suffering from a closed angle glaucoma, since when the pupil dilates the disease may get worse quickly. It must also take special care when the patient has cataracts in the eyes, because the lens may be thickened. Your doctor will know how to intervene properly to carry out the test without unnecessary risks.
Pregnancy and lactation: is a test that can be performed safely during pregnancy and lactation.

How the eye examination

To get an eye examination, when you get to the consultation of ophthalmologist the nurse will begin to instil you with a few drops of eye drops in the eye that you gradually dilate the pupil; These drops can be a little escocer. This process may take several minutes to an hour. The nurse will be checking how dilates the pupil until you consider that it is in the ideal State to be able to perform the test.
Then you'll enter the consultation of ophthalmologist and you sentarás in a Chair. The lights will turn off to facilitate the vision of the interior of the eye. If your doctor uses a slit lamp, it will ask you that you support the Chin and forehead on a metal structure, to gaze and use magnifiers and lights that allow the eye exam.
If the ophthalmoscope is direct, the doctor will need to see an eye first and then the other eye. Ophthalmoscope used is indirect, the doctor can see both eyes at the same time with a light that will normally be placed in their own front; in this case, you'll stay reclining or lying. During the test, your doctor will ask you that you set the view on one point and that you not blinking for a few seconds.
Once the eye examination you can relax the look and perform a normal life. That Yes, the dilation of the pupils will last you a few more hours, so the sunlight bothered you and you can have a visual disturbance; the most frequent is you can not read, so it is recommended to postpone activities that require it.
It not always necessary that the eye examination is conducted in these conditions. Neurologists and other physicians in the emergency room to perform the examination of fundus oculi unexpanded before the pupil, since there's no time to do so. This does not allow an in-depth study of the retina and other parts of the eye, but it is possible to observe the essential parts that interest them (for example, the presence of papilledema).

Complications of the eye examination

Serious complications on the fundus exam are not very frequent. Some that can ever occur are:
  • Irritation of the ocular conjunctiva or itching intense eye to eye you drops to dilate the pupil.
  • Allergy to the medication used to dilate the pupil.
  • Aggravation of an attack of acute glaucoma, to dilate the pupil the channel which drains fluid from the inside of the eye closes and can greatly increase the intraocular pressure.

Results of the examination of fundus oculi

The study of fundus allows the ophthalmologist see eye inside in real time, so that the findings can be interpreted immediately and establish a successful diagnosis. However, the doctor usually write a report describing all changes if any.
The results of an eye examination report will describe all parts of the inside of the eye and its State. The essential parts have to describe are the optic nerve, macula or central area of vision, small blood vessels, and the periphery of the retina. The other structures are usually described only when they are altered.
If the eye examination does not have a diagnostic purpose, but is used for the monitoring of systemic diseases such as diabetes or hypertension, it is often necessary to take photographs that the doctor may be stored on your computer or print at the time, to attach them to your medical history. If it is not possible to take pictures, the description will have to be more precise.
When it is not possible to perform a dilated eye exam you can resort to other techniques depending on what you want to study. An ultrasound of the eye can be to see internal alterations, or for studies of retinal scan of coherence Optics (OCT), which allows to get images of each cell of the retina as if it were a biopsy can be performed.
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