Special Tests: Optical Coherence Tomography [ OCT], Corneal Topography

Subtle changes in the retina and cornea can affect the vision tremendously which is why special tests such Optical Coherence Tomography [ OCT], and Corneal Topography are needed.  Dr. Duplessie uses Special Tests: Optical Coherence Tomography [ OCT], Corneal Topography to analyze the retina and the cornea for detailed analysis.

Special Tests:

Retina and Optic Nerve Optical coherence tomography (OCT)

Retinal OCT is a non-invasive imaging test that uses light waves to take cross-section pictures of your retina, the light-sensitive tissue lining the back of the eye.

 

OCTVisante,Special Tests: Optical Coherence Tomography [ OCT], Corneal Topography

 

Normal Retinal OCT reading

This is an retinal OCT of a normal macula. The central depression is normal and represents the area the retina where our most acute vision is generated from and is responsible for the  central part of your vision.

 

OCT normal

 

Special Tests: Optical Coherence Tomography [ OCT], Corneal Topography

Fovea = area of most acute [best] vision.

Abnormal Retinal OCT Reading

 

oct-abnormal,Special Tests: Optical Coherence Tomography [ OCT], Corneal Topography

 

 

Optical coherence tomography (OCT) is useful in diagnosing many eye conditions, including:

 

Macular hole:

The macula is an anatomic term referring the the area of the retina that  provides the sharp, central vision we need for reading, driving, and seeing fine detail. It is thin delicate area of the retina.  A macular hole is a hole in the retina and can cause blurred central vision.

 

Special Tests: Optical Coherence Tomography [ OCT], Corneal Topography

Macular hole with adjacent epiretinal membrane

 

Special Tests: Optical Coherence Tomography [ OCT], Corneal Topography

Full Thickness macular hole

 

Special Tests: Optical Coherence Tomography [ OCT], Corneal Topography

Macular hole by OCT

Macular pucker {Epiretinal Membrane}

The macula is an anatomic term referring to the part of the retina responsible for the most acute vision in the eye [fine reading and distance vision].  The retina wrinkles due to traction by scar tissue which is called an epiretinal membrane.  An older term would be cellophane maculopathy.  The wrinkled retina does not work as well as a normal retina and if the wrinkling is severe requires surgical correction.  Spontaneous resolution of the problem is also possible.

 

Special Tests: Optical Coherence Tomography [ OCT], Corneal Topography

The white tissue running from the optic nerve to the retina is causing traction and distortion of the retina

Special Tests: Optical Coherence Tomography [ OCT], Corneal Topography

Red free photography of the retina showing the epiretinal membrane causing traction

Special Tests: Optical Coherence Tomography [ OCT], Corneal Topography

Macular edema:

The most common cause of Macular edema is diabetic retinopathy but it refers to swelling\ leakage and accumulation of fluid in the macula [area of best vision in the retina] from abnormal blood vessels.  It has many causes including

  • Post op inflammation
  • Epinephrine
  • Uveitis
  • Age related macular degeneration
  • Retinal vein occlusion
  • Blockage in the small veins of the retina, due to radiation, macular telangiectasis
  • Side effects of certain medications
  • Certain genetic disorders, such as retinoschisis or retinitis pigmentosa

Diabetic macular edema is often treated with anti-VEGF medicine such as Lucentis or Avastin.

 

Special Tests: Optical Coherence Tomography [ OCT], Corneal Topography

Optic nerve edema with macular star

Age-related macular degeneration;

Age-related macular degeneration (AMD) is a leading cause of severe vision loss.  It has two main forms wet [leaky blood vessels] and dry [no leaky blood vessels].  Wet is the more aggressive force.  In severe  AMD there is a decrease in your central vision with difficulty appreciating fine details.  There are treatments for it. See macular degeneration pages for more details. https://www.michaelduplessie.com/macular-degeneration-dry-vs-wet-avastin-lucentis-aflibercept-injections/

 

Special Tests: Optical Coherence Tomography [ OCT], Corneal Topography

Wet age related macular degeneration

Glaucoma:

Glaucoma is frequently called the ‘thief of sight’ because it causes a painless, silent loss of vision.  It typically can only be detected with an eye examination.  The most common form involves elevated eye pressure damaging the optic nerve leading to blindness.  It can be treated effectively with medical and surgical therapy.  Please see section regarding glaucoma https://www.michaelduplessie.com/glaucoma-overview-risk-causes-diagnosis-treatment-prognosis/

Special Tests: Optical Coherence Tomography [ OCT], Corneal Topography

Optic nerves very difference between eyes. Abnormal cupping [cup/disc ratio]

Central serous retinopathy:

This retina/choroidal disease typically occurs in healthy male patients, often with Type A personalities. Typically, patients may have central vision loss/ distortion.  A variety of other visual presentations are possible. It responds well to treatment and time.

Special Tests: Optical Coherence Tomography [ OCT], Corneal Topography

 

Diabetic retinopathy:

Diabetic retinopathy  refers to a group of eye problems that people with diabetes may face as a complication of diabetes. All can cause severe vision loss or even blindness.  The Diabetic section the the website reviews ocular Diabetes: Retinopathy, Proliferative Retinopathy, Treatment, Symptoms.https://www.michaelduplessie.com/diabetes-retinopathy-proliferative-retinopathy-treatment-symptoms/

Special Tests: Optical Coherence Tomography [ OCT], Corneal Topography

Optic Nerve hemorrhage

Disorders of the optic nerve

Special Tests: Optical Coherence Tomography [ OCT], Corneal Topography

Optic nerve astrocytoma

The OCT exam is helpful in determining changes to the fibers of the optic nerve, and the retina.

 

Visante – Anterior Segment [front of the eye] OCT:

The Visante OCT from Zeiss (Carl Zeiss, Germany) provides excellent high-resolution images of the anterior segment of the eye. It is a noncontact instrument that captures its images quickly.

Originally, Optical coherence tomography was only a  tool for analyzing the retina. Technological advances have made it a valuable tool for evaluating the front of the eye as well.

Anterior segment OCT I can be used in the:

  • Evaluation of the angle in glaucoma patients;
  • Evaluation of the cornea in refractive surgery patients—particularly LASIK patients;
  • Measuring the anterior chamber for certain phakic intraocular lenses; and as an
  • Evaluating the cornea for Ectasia
  • In pre-operative evaluations for cornea procedures, such as PTK and corneal transplants.

 

 

visante-oct-image,Special Tests: Optical Coherence Tomography [ OCT], Corneal Topography

 

 

Special Tests: Optical Coherence Tomography [ OCT], Corneal Topography

Corneal Topography:

Corneal topography, also known as photokeratoscopy or videokeratography, is a non-invasive medical imaging technique for mapping the surface curvature of the cornea, the outer structure of the eye.  The corneal is responsible for 70% of the eyes focusing power. The corneal topographer corneal topography is a process for mapping the surface curvature of the cornea, similar to making a contour map of land.  Abnormal curvatures of the cornea which are not evident by slit lamp microscope examination can be detected with a corneal topographer. A normal corneal topographic map is essential for corneal refractive surgical procedures.

 

Special Tests: Optical Coherence Tomography [ OCT], Corneal Topography

Corneal Topographer with sample printout in background

 

 

Asymmetrical Astigmatism:

 

Special Tests: Optical Coherence Tomography [ OCT], Corneal Topography

Asymmetrical Astigmatism – Keratoconus. Notice steeping {red mountain] on printout

A patient with keratoconus cannot have lasik or any form of refractive surgery

 

Symmetrical Astigmatism:

Special Tests: Optical Coherence Tomography [ OCT], Corneal Topography

The amount of red is reasonably equal between the upper and lower half of the eye. This is reasonably symmetrical astigmatism