OPTO 4101 Contact lens 1 lab L 01

OPTO 4101: Contact lens 1 - lab L 01: Slit lamp microscope Mohammed A. M Aljarousha Department of Optometry Faculty of Allied Health Sciences Islamic University-Gaza

Slit lamp microscope part 1

Definition of slit lamp - The slit lamp is an instrument consisting of a high-intensity light source that can be focused to shine a thin sheet of light into the eye. - It is used in conjunction with biomicroscope. - The lamp facilities an examination of the anterior segment & posterior segment of the human eye. - The binocular slit-lamp examination provides a stereoscopic magnified view of the eye structures in detail, enabling anatomical diagnoses to be made for a variety of eye conditions.

The practice of slit lamp

Prepare the instrument and patient • • Switch on power & unlock base screw. Cleaning the forehead band. Changing paper strip from chinrest. Adjust eyepieces to correct for examiner’s refractive error and interpupillary distance. Comfortable sitting of patient and the examiner. Give instructions to the patient to cooperate. Proper positioning of the patient. Target fixation.

Chronology for slit-lamp examination

Illumination techniques Slit Width control knob Narrow to fully open slit illumination achieved by rotating this knob

Slit height control knob Short to long slit illumination achieved by rotating this knob

Direct illumination • Direct diffuse illumination • Direct focal illumination o Beam o Conical section (pinpoint)

Direct diffused illumination • Illumination of the eye with a broad, unfocused light beam • Directed obliquely between 30 -45 • Magnification 6 x to 10 x Light source Biomicroscope

Direct diffused illumination Light source Biomicroscope • Application General gross overview of eyelids, lashes, conjunctiva, sclera, pattern of redness, iris, pupil, gross pathology, ant capsule of lens.

Direct focal illumination • • Illumination and observation are focused in the same plane slit width narrow to broad Illumination angle 45° to 60° Magnification 10 x-40 x Biomicroscope

Direct focal illumination • • • Application Cornea in detail Anterior chamber Crystalline lens Anterior part of vitreous Grading cell and flare in anterior chamber

Beam direct illumination - The microscope is usually directed straight ahead but may also be moved to an angle opposite the illuminator. - The greater the angle between the illuminator and the microscope, the greater the width of the illuminated section. - A very narrow beam (optical section) directed onto the cornea can be used to evaluate corneal shape, elevation, and thickness.

Beam direct illumination • Application Observe: cornea, iris, lens, vitreous

Conical section • • Assessment of particles floating in the A/C Narrow, short & bright slit of light 45°-60° light source directed to pupil Magnification 16 x-25 x • Application Inflammatory cells, flare, pigmented cells