The Slit Lamp Exam

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Transcript of The Slit Lamp Exam

Carlanne Dukes, DO, MBA, FACEP Emergency Medicine Residency Director St. Josephs Mercy of Macomb Clinton Twp, MI dukesca@trinity-health.org

Credit

http://eyelearn.med.utoronto.ca/default.htm University of TorontoThe Ophthalmology Teaching Website

The Slit Lamp Exam

Although the slit lamp has become almost universally available to the emergency room physician, a reluctance on the part of many physicians to use this device persists

Magnification

a patient who came to the emergency with a sensation of a foreign body in the eye. The emergency physician, without the aid of magnification, spent 20 to 30 minutes trying to remove the small brown dot that is just visible in this slide.

Magnification

the same patient using the magnification, the brown dot can actually be seen to be two brown nevi, benign pigmented accumulations of cells

Fluorescein & Cobalt Blue Filter

By the fluorescence elicited by the cobalt blue illumination, subtle lesions of the cornea, including smaller corneal abrasion, herpes simplex, dendritic ulcers and foreign bodies can be easily seen

Landmark IdentificationLandmark 1 will be the anterior surface of the cornea, the first to be struck by the slit lamp beam. Landmark 2 will be the posterior surface of the cornea where the slit lamp beam exits from the cornea.

Landmark IdentificationLandmark 3 will be the plane of the iris and lens surface. Landmark 4 will be the posterior surface of the lens which has a reverse curve and can be most easily seen with the beam angled more closely to the line of observation

Landmark Identification

landmarks 1, 2 and 3 are out of focus but landmark 4 is in focus and a white opacity on landmark 4 is seen - the typical posterior subcapsular cataract produced by extended use of topical steroids and easily identified with the slit lamp

Landmark Identification

The nature of these lines becomes apparent with the angled slit beam

Landmark Identification

Between landmarks 2 and 3 a vertical transparent membrane may be seen which peels off the back of the cornea superiorly and curls up upon itself inferiorly. The upper line seen in the flatillumined view was where the endothelium had been peeled off the back of the cornea

Landmark Identification

Landmarks 4 and 3 can be seen, 1 and 2 are out of focus. Between landmarks 4 and 3 there is a big, diffuse yellow haze. Its position relative to landmarks 3 and 4 reveals that it is right in the center of the lens and hence it is the nucleus.

Landmark Identification

a mature cataract is being viewed with flat illumination. This reveals no information with regard to the position of the cornea relative to the lens and iris,

Landmark Identification

the line of slit beam on the front of the iris is seen to be coincident with the slit beam exit on the back of the cornea, indicating no anterior chamber at this site and the iris is plastered against the back of the cornea.

Landmark Identification

Observe the relation between landmarks 1 and 2. One and 2 proceed from above to below with uniform separation until just below the mid-point. Landmark 1 can be seen to dip in and out, revealing a shallow pit which was left after foreign body removal.

Landmark Identification

landmarks 1 and 2 can be seen coming out from below and joining, indication that the stroma of the cornea is gone in the central portion as a result of multiple surgical procedures on this cornea

Landmark Identification

The light is coming from the observer's right-hand side and strikes first of all the cornea, and then the iris and lens. A large gap may easily be seen between the slit beam on the cornea and the slit beam on the lens.

Thinning the Cut

Thinning the Cut

Depth

the cornea of an eight-year-old boy is demonstrated in which the wound to his cornea is Vshaped and resulted from a brass hose coupling slipping and flying up and cutting the front of his cornea

Depth

the slit lamp beam has been moved further to the left and the line of the cut in the cornea again is demonstrated to be a shelving rather than a penetrating incision.

Depth

Easy Miss without Slit Lamp

An enamel flake cut the eye in a shelving manner which was self-sealing so that there was no pupillary distortion. There was no prolapsed iris, and without the application of the angled slit beam to achieve serial optic sections the discovery of the wound which did in fact penetrate to the interior of the eye could not have been discerned at the initial encounter.

Easy Miss without Slit Lamp

Easy Miss without Slit Lamp

A nail slipped and stuck in the patients eye. He came to the emergency department, but the emergency intern, who was on his first week in service, had no facility with the slit lamp. He did use fluorescein dye and found that there was staining, but was unsuccessful in reaching the ophthalmologist on call. He brought the patient back to the clinic two days later at which time the typical iris distortion, linear discontinuity on the cornea and protruding iris indicated a penetrating wound of the eye.

Easy Miss without Slit Lamp

Easy Miss without Slit Lamp

Magnication would have revealed protruding iris tissue and the diagnosis could have been made at the initial encounter. After the eye was sewn up the patient was found to have a vitreous abscess. This was removed surgically following which the retina detached.