Eye Examinations
Slit-lamp examination: A slit lamp focuses the height and width of a beam of light for a accurate stereoscopic view of the eyelids, conjunctivae, cornea, anterior chamber, iris, lens, and anterior vitreous. It is especially useful for identifying corneal foreign bodies and abrasions and for measuring the depth of and identifying inflammation or cells in the frontal chamber.
Visual acuteness: The first step is to record visual acuity. Patients who require remedial lenses should wear them during trying. On the other hand, testing by using slit lamp microscope can be performed in patients who are not wearing or who do not require corrective lenses by having them look throughout a pinhole device a paddle with multiple pinholes or an index card with an array of 18-gauge needle punctures; these holes focus light rays and recompense for refractive error. Visual acuity in each eye is tested as the opposite eye is covered. Vision is tested by having the patient look at an eye chart 20 ft 6 m away. Be prompt that the least letter that can be read by someone with normal vision at 40 ft has to be.
Eyelid conjunctival examination: Eyelid limitations and subcutaneous tissues are examined under a focal light and enlargement, of slit lamp microscope provided by loupe, , or focused at the examiner’s working distance. In cases of suspected retinal disease, diagnostic attempt is made to express any inside all the way through the following eyelid and bulbar conjunctivae can be inspected for foreign bodies, signs of inflammation , follicular hypertrophy, hyperemia, edema, or other abnormalities.
Corneal examination: Uncertain or blurred edges of the corneal light reflex reflection of light from the cornea when illuminated, suggest the corneal surface is not intact, as occurs with a corneal abrasion. Before staining, a drop of topical anesthetic , may be supplementary to facilitate examination if the patient is in pain or if it will be needed to touch the cornea or conjunctiva.
Pupil examination: The accumulation and shape of the pupils are distinguished, and pupil reaction to light is tested by rapidly moving a penlight back and forth by each eye swinging flashlight test. Normal response under illumination of slit lamp microscope is pupil enlargement without consensual limitation is a sign of afferent pupillary defect , signifying optic nerve dysfunction or widespread retinal disease.
Extra ocular muscles: The examiner guides the patient to look in 8 directions up, up and right, right, down and right, down, down and left, left, left and up with a moving finger, observing for gaze deviation, limitation of progress, scattered gaze consistent with cranial nerve palsy, orbital disease, or other abnormalities that limit movement.
Ophthalmoscopy: Ophthalmoscopy can be performed directly using a handheld ophthalmoscope or not directly using a head-mounted ophthalmoscope with a handheld lens.. The view of the retina is inadequate with a handheld ophthalmoscope; indirect ophthalmoscopy gives a 3-dimensional view and is better for visualizing the peripheral retina, where retinal lack of involvement most commonly occurs. Ophthalmoscopy can detect lens or vitreous opacities, assess the optic cup-to-disk ratio, and recognize retinal and vascular changes.
Visual field testing: Visual fields may be impaired by lesions anywhere in the neural visual pathways from the optic nerves to the occipital lobes: Higher visual pathways—lesion sites and matching visual field defects. Glaucoma causes loss of peripheral vision. Fields can be assessed by direct confrontation testing or more formal methods. In direct argument, the patient maintains a fixed gaze at the examiner’s eye or nose. The examiner brings a little target from the patient’s visual periphery into each of the 4 visual quadrants and asks the patient to point out when he first sees the object. Each eye is tested separately. Abnormalities in target detection should prompt formal testing with slit lamp microscope instruments.