BIO MICROSCOPY

ANATOMY OF ANGLE OF ANTERIOR CHAMBER

SLIT LAMP BIO-MICROSCOPYThe 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 a biomicroscope. The lamp facilitates an examination of the Anterior segment and Posterior segment of the human eye, which includes the eyelids, sclera, conjunctiva, iris, lens, and cornea.

PARTS:

Observation system (MICROSCOPE)

Illumination system (Slit-Lamp)

Mechanical System (engineering support)

OPTICS• It works in the same principle as a compound microscope. • OBJECTIVE LENS (+22D) is towards the object (eye of the

patient)• EYEPIECE (+10 to +14D) is towards the examiner.• Illuminating system can be adjusted to vary the width,

height and angle of incidence of light beam.

SLIT LAMP BIOMICROSCOPY ROUTINE1. Patient adjustment2. Instrument adjustment3. Beginning slit lamp examination: a. Examination should be carried out in semi dark room so that examiner’s eyes are partially dark adapted to ensure sensitivity to low intensity of light.B. Diffuse illumination should be used only for short timec. Minimum exposure of retinad. Medications may be mistaken for pathologye. Low magnification first, then high magnification.

METHODS OF ILLUMINATION Diffuse illumination

Direct illumination

Indirect illumination

Retroillumination

Specular illumination

Sclerotic scatter

Oscillatory illumination of Koeppe

ANATOMY OF ANGLE OF ANTERIOR CHAMBER

• Plays an important role in process of aqueous drainage.• The angle width varies in different individuals and plays

a vital role in pathomechanism of different types of glaucoma.

AQUEOUS OUTFLOW SYSTEM

TRABECULAR MESHWORK:• Sieve-like structure through which aqueous

humor leaves the eye. • Uveal Meshwork: Extends from Iris root and

ciliary body to Schwalbe’s line. • Corneo Scleral Meshwork: Scleral spur to

lateral wall of the scleral sulcus.• Juxtacanalicular Meshwork: It consists of

juxtacanalicular space and cells. The juxtacanalicular cell cytoplasmic processes attach externally to the processes arising from the innerwall endothelium of schlemm’s canal and internally to processes arising from the cells of corneoscelral meshwork.

Schlemm’s Canal

Endothelial lined oval channel present circumferentially in the scleral sulcus.The endothelial cells of the inner wall are irregular, spindle shaped and contain giant vacuoles. The outer wall of the canal is lined by smooth flat cells and contains opening of collector channels

Collector channels These are called intrascleral aqueous vessels, are about 23-25 in number and leave the schlemm’s canal at oblique angles to terminate in episcleral veins.

• DIRECT SYSTEM: Formed by larger vessels which run a short intrasceral course and terminate directly into episcelral veins.

• INDIRECT SYSTEM: Formed by smaller collector channels which form an intrasceleral plexus before eventually going into episcelar veins.

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