Slit lamp examination

What is a slit lamp?

A slit lamp is a special microscope that produces a narrow beam of light that illuminates the eye from different angles. The slit lamp also has a magnification function that allows the vet to see the structures of the eye in detail. The slit lamp can also be connected to a camera or video device to take pictures or videos of the eye.

How is a slit lamp examination performed in dogs?

A slit lamp examination in dogs is usually not painful and does not require anesthesia. However, the dog must be calm and cooperative so that the vet can examine the eye thoroughly. Therefore, it may sometimes be necessary to sedate or restrain the dog. In addition, the dog should not be given any eye drops or ointments before the examination, as these can distort the results.

The slit lamp examination begins with the vet inspecting the eye with a dim light source to look for signs of inflammation, injury or foreign bodies. The slit lamp is then switched on and the vet directs the beam of light at the eye. The vet moves the slit lamp and the beam of light back and forth to look at the different sections of the eye. The vet looks for changes in the shape, color, transparency or position of the eye structures. The vet may also use different filters or lenses to highlight or measure certain aspects of the eye.

The slit lamp examination usually takes about 10 to 15 minutes per eye. The vet will document his findings in writing or verbally and discuss them with you.

What preparations should you make?

If you have an appointment for a slit lamp examination for your dog, you should make some preparations to make the examination as comfortable as possible. Here are some tips:

• Educate yourself on the process and purpose of the exam and ask any questions you have.
• Bring any documentation you have about your dog's history, such as vaccination records, medications or previous eye examinations.
• Avoid giving your dog eye drops or ointments before the examination unless the vet has given you explicit permission.
• Do not feed your dog just before the examination as he may feel nauseous.
• Keep your dog on a lead and reassure him with your voice or petting.
• Be patient and understanding if your dog is nervous or restless.

What results can you expect?

The slit lamp examination may reveal different findings depending on whether your dog is healthy or has an eye condition. Some common findings are:

• Normal eye: the eye has a clear cornea, a round pupil, an evenly colored iris, a transparent lens and a clear vitreous. There are no signs of inflammation, bleeding or foreign bodies.
• Corneal diseases: The cornea is the outer layer of the eye that protects the eye and refracts light. Corneal diseases can lead to clouding, ulcers, scarring, pigmentation or injury to the cornea. Possible causes are infections, injuries, allergies or genetic defects.
• Iris and pupil diseases: The iris is the colored disk that surrounds the pupil. The pupil is the opening that enlarges or shrinks depending on the light conditions. Iris and pupil diseases can lead to changes in the shape, size, color or reaction of the iris or pupil. Possible causes include inflammation, tumors, trauma or congenital anomalies.
• Lens diseases: The lens is the transparent structure behind the iris that focuses light onto the retina. Lens diseases can lead to clouding, displacement or dislocation of the lens. Possible causes include ageing, diabetes, inflammation or genetic defects.
• Vitreous body diseases: The vitreous is the gel-like substance that fills the space between the lens and the retina. Vitreous diseases can lead to clouding, bleeding or inflammation of the vitreous. Possible causes are infections, trauma, retinal detachment or diabetes.

The slit lamp examination can also detect other eye diseases such as glaucoma, cataracts or retinal detachment. The vet will explain to you what the findings mean and what treatment options are available.