Ophthalmoscopy is an examination of the back part of the eyeball, which includes the retina, optic disc, choroids and blood vessels. Direct ophthalmoscopy is performed in a darkened room. Wherein the examiner performs the examination by projecting a beam of light from an ophthalmoscope, through the pupil, to view the back of the eyeball. An ophthalmoscope is an instrument about the size of the flashlight, with a light source and a disk of rotating lenses. The magnification is obtained by using the direct ophthalmoscope. It occurs because the eye itself is a simple magnifier. The rotating lenses incorporated in the instrument are used to correct the focusing error of the examiner or the patient examined. In slit-lamp ophthalmoscopy, the patient will be seated and the same instrument is used in examining the front part of the eye. An additional lens will be held close to the eye enable the ophthalmologist to see the interior part of the eye or fundus.

The advantage of the slit-lamp ophthalmoscopy is that, it has a three- dimensional view in addition to the magnification of direct ophthalmoscopy, but not as wide as indirect ophthalmoscopy. Using indirect ophthalmoscopy the patient will either lie or sit in a semi-reclining position. The examiner wears an instrument on the head resembling a miners light. While holding the eye open and using a hand-held instrument, the examiner shines a very bright light into the eye. And some pressure may be applied to the eyeball using a small blunt instrument and the patient will be asked to look in various directions. The examination of indirect ophthalmoscopy takes between 5 to 10 minutes. The presence of bright light will be uncomfortable to the patient, but the test is not painful. The examination requires more skill and time than the other forms of ophthalmoscopy, but it has an advantage of allowing the ophthalmologist to see the entire retina. The preparation for indirect ophthalmoscopy and slit-lamp ophthalmoscopy is performed after an eye drops are placed to dilate the pupils. While direct ophthalmoscopy can be performed with or without dilation of the pupil. The dilating drops may impair the focusing of the eyes for several hours. Therefore, arrangements should be made for someone else to drive after the examination. That’s why wearing sunglasses or tinted lenses will make the patient with dilated pupils more comfortable. Before performing the test the patient should tell the examiner if he or she are allergic to any medication, are taking medication, have glaucoma or a family history of glaucoma. Usually in direct ophthalmoscopy the patient will hear a clicking sound. And the bright light shone into the eyeball may cause brief after-images to be seen. But with indirect ophthalmoscopy the light is brighter, so the sensation of seeing after-images are greater. Ophthalmoscopy is performed as part of routine physical or complete eye examination. It is used to detect and evaluate the symptoms of retinal detachment or eye disease such as glaucoma. It is also performed if a patient is suspected of diabetes, hypertension or other vascular disease.