Ophthalmoscopy is an examination of the back part of the eyeball (fundus), which includes the retina, optic disc, choroid, and blood vessels.
How the test is performed
Direct ophthalmoscopy: You will be seated in a darkened room. The examiner performs this common examination by projecting a beam of light from an ophthalmoscope, an instrument about the size of a flashlight, through the pupil to view the back of the eyeball.
The magnification obtained by using the direct ophthalmoscope occurs because the eye itself is a simple magnifier. The rotating lenses incorporated in the instrument are used to compensate for the refractive error of the examiner or the patient being examined.
Slit-lamp ophthalmoscopy: You will be seated at the same instrument used in examining the front part of the eye. An additional lens will be held close to the eye to enable the doctor to see the fundus. This has the advantage of a stereoscopic view in addition to the magnification of direct ophthalmoscopy. The view is much wider than that of direct ophthalmoscopy, but not as wide as indirect ophthalmoscopy.
Indirect ophthalmoscopy: You will either lie or sit in a semi-reclining position. The examiner performs this examination by holding the eye open. The examiner wears an instrument on the head resembling a miner’s light. While holding the eye open and using a hand-held instrument, the examiner shines a very bright light into the eye. Some pressure may be applied to the eyeball using a small, blunt instrument, and you will be asked to look in various directions.
This examination takes between 5 and 10 minutes. The bright light will be uncomfortable, but the test is not painful. This examination requires more skill and time than the other forms of ophthalmoscopy, but has the advantage of allowing the doctor to see the entire retina.
How to prepare for the test
Indirect ophthalmoscopy and slit-lamp ophthalmoscopy are performed after eye drops are placed to dilate the pupils. Direct ophthalmoscopy can be performed with or without dilation of the pupil.
The dilating drops may impair focusing of the eyes for several hours. Therefore, arrangements should be made for someone else to drive after the examination. Wearing sunglasses or tinted lenses will make the patient with dilated pupils more comfortable.
You should tell the examiner if you:
- Are allergic to any medications
- Any medications are being taken
- Have glaucoma or a family history of glaucoma
Infants and children:
The physical and psychological preparation you can provide for this or any test or procedure depends on your child’s age, interests, previous experiences, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child’s age:
- Infant test or procedure preparation (birth to 1 year)
- Toddler test or procedure preparation (1 to 3 years)
- Preschooler test or procedure preparation (3 to 6 years)
- Schoolage test or procedure preparation (6 to 12 years)
- Adolescent test or procedure preparation (12 to 18 years)
How the test will feel
Direct ophthalmoscopy: As the scope is focused, a clicking sound will be heard. The bright light shone into the eyeball may cause brief after-images to be seen.
Indirect ophthalmoscopy: The light is brighter with indirect ophthalmoscopy, so the sensation of seeing after-images may be greater. Pressure put on the eyeball by the blunt instrument may be slightly uncomfortable, but should not be painful. The fundus can usually be seen through cataracts.
If eyedrops are used, they may produce a brief stinging sensation when put in the eyes and a medicinal taste in the mouth caused by the medication draining from the tear ducts into the throat.
Why the test is performed
Ophthalmoscopy is performed as part of a routine physical or complete eye examination to detect and evaluate symptoms of retinal detachment, eye disease such as glaucoma , or if diabetes, hypertension, or other vascular disease is suspected.
The retina, blood vessels, and the optic disc should appear normal to the examiner.
What abnormal results mean
Eye diseases, such as cloudy vitreous, detached retina, optic nerve degeneration or swelling, macular degeneration, and changes caused by glaucoma can be detected. Diabetes, hypertension (high blood pressure), and many systemic diseases can also be detected.
Additional conditions under which the test may be performed:
- CMV retinitis
- Hypertensive retinopathy
- Macular degeneration
- Melanoma of the eye
- Noninsulin-dependent and insulin-dependent diabetes mellitus (NIDDM and IDDM)
- Optic neuritis
- Retinal detachment
What the risks are
The test itself involves no risk. The dilating eye drops may rarely produce nausea, vomiting, dryness of the mouth, flushing, dizziness, or an attack of narrow-angle glaucoma. If the latter is suspected, drops generally are not used.
Since it can detect the initial stages and early effects of heart and blood vessel disease (particularly high blood pressure), brain disease, diabetes, and specific eye diseases, ophthalmoscopy is one of the most valuable tests. It is considered to be 90-95% accurate.
by Dave R. Roger, M.D.
All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.