[...]... (Figures 1- 3 A and 1- 3 B) (The power of the oculars is fixed You are actually changing the objective lens when you change magnification) This can be done during the exam itself and does not interrupt the observer or the patient Magnifications of 6X, 10 X, and 16 X are adequate for most exam purposes Higher magnifications can be achieved by removing the standard oculars and inserting stronger-powered ones The. .. However, most illumination techniques require that the light be positioned at an angle to the scope A marked dial (angle scale index) at the base of the arm indicates degrees (Figure 1- 5 ) The microscope The Slit Lamp 3 Figure 1- 1 Topcon slit lamp model SL-2E with horizontal prism reflected light source (Photo courtesy Topcon.) Figure 1- 2 Topcon slit lamp model SL-3E with vertical illumination source (Photo... photography The light source of the slit lamp is unique to this microscope and is the feature that makes it so adaptable for looking at the eye The light is controlled by a transformer, which provides various voltage settings The beam of light can be changed in intensity, height, width, direction or angle, and color during the exam with the flick of a lever or turn of a dial (Figure 1- 4 A and 1- 4 B) The majority... may also be visible if the lens is clear Although there are numerous manufacturers and models of slit lamps, there are basically only two styles The first utilizes a horizontal prism reflected light source (Figure 1- 1 ) The second has a vertical illumination source (Figure 1- 2 ) The microscope is mounted on a stage that is designed for movement of the microscope and positioning of the patient Microscope... the binocular observer a stereoscopic (3-dimensional) view of the eye Thus, another name for the instrument is the biomicroscope Because the ocular structures can be examined dimensionally, the location of abnormalities can be determined with great precision The slit lamp is used to examine the external ocular adnexa, external eye, anterior chamber, iris, and crystalline lens The anterior face of the. .. The actual magnification of what you see through the slit lamp is derived by multiplying the power of the oculars with the power of the objective lens Thus, if your oculars are 10 X and the objective lens is 1. 6X, the total magnification will be 16 X In addition to magnification, some oculars have an internal line or grid for measuring ocular structures Other eyepieces incorporate an angle scale that is... in and out (toward and away from the patient) allows the observer to focus the microscope at various depths Twisting the joystick (or a wheel at its base) moves the microscope up and down, allowing the examiner to view various structures The joystick can also be used to move the microscope from side to side, allowing scanning and easy movement from one eye to the other The microscope has various magnification... on the pages Chapter 1 The Slit Lamp K E Y P O I N T S • The slit lamp microscope is uniquely designed to give a threedimensional view of the eye and its structures • Because the slit lamp provides a binocular view, the location of abnormalities can be determined with great precision • The magnification of the microscope is provided by the oculars and the objective lenses • The slit lamp should be... OphA OphT CL Chapter 1 Instrumentation The eye is one of the most fascinating structures of the body A great deal of this fascination hinges on the fact that it is the only organ that we can look directly into without having to cut and/or insert a special scope The slit lamp is a microscope designed specifically to examine the eye It is composed of a microscope and a light source The microscope is binocular;... majority of the microscopic eye exam is done with the light beam set at maximum height but with a narrow width that produces a slit of light, hence the name slit lamp In addition, the light source (illuminator) moves independently of the microscope unit, making various types of illumination and views of ocular structures possible A click-stop indicates when the light is directly aligned with the microscope . references and index. ISBN -1 3 : 97 8 -1 -5 564 2-7 4 7-3 (alk. paper) ISBN -1 0 : 1- 5 564 2-7 4 7-6 (alk. paper) 1. Ocular biomicroscopy. I. Sanders, Valerie N. II. Title. III. Series. [DNLM: 1. Eye. 2. Microscopy. Robert Campbell Copyright © 2006 by SLACK Incorporated ISBN -1 0 : 1- 5 564 2-7 4 7-6 ISBN -1 3 : 97 8 -1 -5 564 2-7 4 7-3 All rights reserved. No part of this book may be reproduced, stored in a retrieval system. scale index) at the base of the arm indicates degrees (Figure 1- 5 ). The microscope 2 Chapter 1 OptA OptT OphA OphT CL The Slit Lamp 3 Figure 1- 1 . Topcon slit lamp model SL-2E with hori- zontal prism