Slit Lamp Test

Slit lamp test is used to examine the eyes from a three dimensional view. Different parts of the eyes like the anterior and the posterior segments are viewed during the test. The front part of the eye including the clear, cornea (outer covering), the lens, iris, and the vitreous gel (front section of the gel-like fluid) in the middle of the eye are studied. The slit lamp is a low power microscope combined with a high intensity light source that is focused into a thin beam to shine. The binocular slit lamp provides a magnified view of the eye structures in detail. An additional hand-held lens is used to examine the retina.

Special lenses are placed in between the slit lamp and cornea to view the deeper structure of the eye which includes the retina, optic nerve and the drainage angle (area from where the fluid drains out of the eye). A camera attached to the slit lamp may be helpful in capturing pictures of the eye. To detect foreign bodies in the eye, a special dye (Fluorescein) is used. The eyes are dilated before the test is done so as to widen the pupil for examination.

Various methods are used to conduct the test namely observation by optical section, direct diffuse illumination, retro illumination, indirect illumination, etc.

Slit lamp test diagnosis

Slit lamp tests are used to identify eye problems at an early stage. The test is usually done:

• As a part of routine eye examination.
  
• To examine structures at the back of the eye like the retina and the optic nerve.
  
• Help detect glaucoma, macular degeneration, etc.
  
• To examine structures at the front of the eye.
  
• To detect cataract, conjunctivitis, injury to cornea, etc.
  
• To detect presence of foreign bodies in the eye.
  
• Monitoring injuries/bleeding from injuries, etc.
  
• Detect eye problems that may show up due to diabetes, rheumatoid arthritis
  

Slit Lamp Test Procedure

Slit lamp test is performed by an ophthalmologist or optometrist. The test takes about 5-10 minutes. The following steps are followed:

• Eyes are dilated to widen the pupil for examining the structure of the eye clearly.
  
• Anesthetic eye drops (to numb the eyes) are used in case of removing a foreign body.
  
• Patient is made to sit placing the chin and forehead against the bars on the slit lamp.
  
• The slit lamp is placed in front of the eyes in line with the doctor's eyes. The patient is asked to focus the eyes without blinking in the direction as requested by the doctor.
  
• A narrow beam of light is directed into the eye as the doctor examines through the microscope. A camera attached to the instrument may be used to capture images of different parts of the eyes.
  
• To check for ulcers, scratches or burns, the doctor may use a Fluorescein drop. This dye dissolves in the tears and coats the cornea thus covering the area of scratches, ulcer, etc. This will enable the doctor to examine the injury better.

Hyphema

A Hyphema is an eye condition that refers to pooling or collection of blood inside the anterior chamber of the eye (between the cornea and the iris). The blood may cover the iris partially or totally including the pupil and thereby blocking the vision partly or completely. Trauma to the eye is the most common cause of Hyphema. Injury may take the form of blunt trauma, laceration trauma or abrasion.

Some of other conditions that cause Hyphema are:

• Tumors in the eye
  
• Abnormal blood vessels on the surface of the iris
  
• Herpes virus(eye infection)
  
• Intra-ocular lens problems (artificial lens implants)
  
• Severe diabetes
  
• Blood disorders such as sickle cell anemia

Signs and symptoms of the Hyphema vary according to the severity of the condition. Mild Hyphema may not even be visible to the naked eye or a tiny spot of blood may show up which normally gets absorbed on its own. As the condition progresses, the patient experiences the following symptoms.

• Impaired vision
  
• Eye pain, blurring or loss of vision
  
• Bleeding in the anterior chamber of the eye
  
• Light sensitivity or photophobia

Treatment

Vision and ocular pressure are checked and dilation is done to examine the fundus for retinal detachment or blood elsewhere in the eye. Visual acuity test and slit lamp test allow the eye doctor to check the internal structure of the eye for any other damage. The eye sockets and facial structures might need to be examined with a CT scan in case of severe trauma.

Mild cases of Hyphema heal on their own. When the bleeding is not severe, doctor may recommend certain guidelines to be practiced at home along with sedatives and pain relieving medications. These guidelines include covering the affected eye, elevating the head of the patient to help drain the fluid, bed rest and frequent monitoring of the eye condition. Avoid any medicines containing aspirin, arthritis and non-steroidal medication as it promotes bleeding.

Steroid eye drops are prescribed to control inflammation and pain. Severe cases of Hyphema require an aggressive approach. You can use an eye shield or protective eyewear to prevent the eye from any further injury. If elevated is noticed, blood is drained through surgical intervention to prevent glaucoma or cornea damage.