Common Eye Diseases and Imaging Equipment Used to Detect Them
There are some common eye diseases that can be detected during an annual eye exam. Some of these diseases may affect one’s vision and cause symptoms, and some of them may not affect vision and therefore not cause any symptoms leaving the patient completely unaware that they have an eye disease that may be progressing. Some of these diseases are easily detected by an eye doctor’s view of the retina or optic nerve, and some of these diseases in its early or subtle form require the technology of advanced eye imagining equipment to detect them. The value and advancement of these eye imaging equipment and its role it plays in eye disease detection has taken the eye exam to a very high level. Having the equipment at our disposal and using them to screen every patient during their annual eye exam, has enabled us to confidently say their eyes are healthy and normal.
The Optomap and the OCT (Optical Coherence Tomography) are 2 of the eye imaging equipment we use to screen our patients during their comprehensive eye exam. We use them together because they complement each other. The Optomap produces a wide field image of the surface of the retina, optic nerve, blood vessels and choroid. We look for glaucoma, macular degeneration, retinal tears, retinal detachments, tumors, bleeding from the blood vessels from diseases such as diabetes etc.
The OCT is an ultrasound like device that uses light instead. It splits up the retina and macular into a cross-section of its 10 layers so subtle problems presenting themselves in any of its layers below the surface that may easily be missed by the Optomap or by the doctor’s view, can easily be detected by the OCT image. Think of the retina as a piece of cake. The Optomap views the surface or the icing on the cake while the OCT views the layers of the cake below the icing. In this way, some of these common diseases such as Macular Holes, Diabetic Macular Edema, Vitreo-Macular Traction Syndrome, Choroidal Neo-Vascular Membranes, Central Serous Choroidopathy, Epi-Retinal Membranes etc. that may be more difficult to notice with the Optomap or Doctor’s view can easily be detected by the OCT. In addition, the OCT also images the nerve fiber layer around the optic nerve and the ganglion cell complex in the macular for early glaucoma detection as well as glaucoma disease management and progression.
COMMON EYE DISEASES:
Cataracts: Cataracts occur when the lens inside our eyes become cloudy as a result of the natural aging process of our eyes. They do affect our vision causing blurry, cloudy vision as well as glare. They are detected by a dilated exam. OCT and Optomap are not needed to detect them. Surgery is indicated when reduced vision starts to affect one’s daily activities. The surgeon removes the cloudy lens and replaces it with an intra- ocular lens implant thereby restoring vision.
Glaucoma: Glaucoma also known as the silent thief of sight occurs when the nerve cells and ganglion cells that form the axons of our optic nerves start to die off due to a pressure in the eye that the eye cannot withstand. Advanced stage glaucoma can easily be detected by the doctor’s view of the optic nerve. Early stage glaucoma is best detected by OCT imaging of the nerve fiber layer and ganglion cell complex as well as other tests such as visual field testing. Glaucoma initially does not affect central vision and therefore this type of glaucoma presents no symptoms to the patient. It affects our side vision very slowly and progressively and eventually may advance towards our central vision as the disease progresses. Glaucoma is usually detected at an eye exam and treated with drops to slow down further vision loss. OCT imaging is important to manage and monitor for change and progression of this disease.
Macular Degeneration: This occurs when deposits called drusen start to build up in the deep layer of the retina as well as when the RPE layer in the deep retina starts to get affected. Central vision is affected causing blurred and distorted vision. There are 2 forms – the dry form and the wet form. The dry form can be detected by the Optomap or the doctor’s view of the macular as well as OCT imaging. The wet form is more easily detected by OCT imaging. There is no treatment for the dry form except for certain vitamins to slow down the progression to the wet form. The wet form causes a more devastating loss of vision if not treated early enough. The wet form is treated by laser and needs to be done immediately to prevent further vision loss. OCT imaging and Optomap can be used to manage change and progression of this disease.
Diabetic Retinopathy: This disease causes the blood vessels in the eye to bleed and leak causing hemorrhages and other signs that can easily be detected by the Optomap or the doctor’s view of the retina. Another form of this disease called Diabetic Macular Edema is more easily detected by OCT imaging. OCT imaging is used to manage and monitor the changes of Macular Edema as it is being treated by laser surgery.
Vitreo-Macular Traction/Macular Holes/Epi-Retinal Membranes: As we get older, the vitreous gel in our eyes become liquified. This may cause the vitreous to detach from the retina where it is usually firmly attached. The macular, where we have our central vision is one of those sites where the vitreous is firmly attached to. As the vitreous tugs onto the macular and pulls away from it, it may pull away from it and detach without causing any problems. Sometimes however, it may have such a firm attachment that it may pull part of the macular with it causing a macular hole. It may also leave some cells onto the macular that may form an Epi-Retinal Membrane. Macular Holes and Epi-Retinal Membranes may affect vision and cause distortion of one’s vision. Vitreo-Macular Traction and Macular Holes cannot be easily detected by the doctor’s view of the macular and may not be easily detected by the Optomap either. They are best detected and managed by OCT imaging.
Tumors: Choroidal Nevi are flat benign pigmented lesions at the back of the eye. They usually remain stable and mostly do not grow. They do need to be monitored regularly with imaging to ensure they are not changing or growing as they may rarely turn into a Choroidal Melanoma which is a serious progressive cancer at the back of the eye. Choroidal Nevi do not affect vision and they are easily detected with an Optomap image. Malignant Choroidal Melanomas may not affect vision either unless it is growing near the macular area where our central vision is located. If it grows in the peripheral area and away from the macular, it may go unnoticed by the patient. Choroidal Melanomas can be detected by an Optomap image or through a dilated eye exam.
There are many more eye diseases that can be detected during the annual eye exam with the assistance and use of these equipment. Advanced eye-imaging equipment has come a long way in helping us detect and manage eye disease and it has certainly taken the eye exam to a very high level. All patients deserve the best care possible and imaging has enabled us to provide this higher standard of eye care.