Eye Dork - Eye Have the Answer

The terms Optometrist and Ophthalmologist sound so similar. For those who don't speak our dorky eye language it can be difficult to differentiate between the two. This article will attempt to describe the differences and similarities between these professions. Let me start by saying this post intends to only highlight the educational background of these two professions. I do not intend take anything away from either profession. Every individual practitioner Optometrist or Ophthalmologist has their own unique skill set and billing schedule. For this blog, I will only discuss general trends of each profession. Optometrists are similar to a primary care physician for the eyes, or the Doctor you see on a yearly basis for your physical. Most Ophthalmologists are surgeons, who specialize in different surgeries for the eye. The greatest skill Optometrists possess is in the art of refraction (the 1 or 2 test) and concepts for prescribing glasses and contacts. In their education, Optome...

A copy of the medical history form for our office can be downloaded and printed here. A lot of information is required for this form. It is a bit annoying to fill out, but all of the information does serve a purpose. Your name, address, phone number and identification numbers are required for your insurance company to pay for the eye exam. Also, this information is used to communicate with your primary care Doctor or other specialist (such as a retinal specialist) in the event of an emergency. Medical History is a comprehensive listing of any medical conditions a patient or their family may have. Proper function of the eye is significantly affected by the health of the rest of the body. Also, certain signs identified in a patient's eye can indicate various systemic conditions. Many health conditions can be linked to genetics. For genetic conditions, when one family member has a condition, this represents increased risk of this condition for other family members. Symptoms are ...

The retina is an incredibly complex structure.  This entry will be about the larger structures involved in processing an image. To learn how an image is focused on the retina, check out anterior eye anatomy. If you want to learn about the individual cells of the retina, check out phototransduction (conversion of a light ray into a chemical message for the brain). For information on the utilization and regeneration of vitamin A in the retina, check out the biochemistry of the visual process. The goal of glasses, contact lenses or refractive surgery is to get images focused on the fovea of the macula. The macula is the general pigmented area surrounding and supporting the fovea. The fovea is the specific structure that processes all of the detailed (letters, print) visual information we see. The fovea is a small structure, seen on examination only as a small pinpoint of light. In this small space, the fovea packs in over 10...

For vision to be a continuous process the photoreceptors (rods and cones) must continually regenerate 11-cis retinal. Rods and cones have slightly different ways of doing this. WARNING: this is only for the extremely nerdy. If you aren't very interested in the biochemical processing of vitamin A in the retina, this entry probably isn't for you. For rods: A photon (light ray) is absorbed by pigment within the opsin in the outer segment of the photoreceptor cell. Inside the activated opsin, 11-cis retinal is converted to all-trans retinal and released to the disc of the inner segment of the photoreceptor. Within the disc, all-trans retinal binds phosphatidylethanolamine. This produces N-retinylidine-phosphatidyl-ethanolamine (NRPE). ATP binding cassette transporter carries the NRPE complex to the cell membrane of the disc. At the cell membrane the all-trans retinal portion of the NRPE complex is transported to the cytoplasm within the cell body of the photoreceptor. Insi...

Light rays from an image are focused onto the retina by glasses or contacts and the anterior structures of the eye. Light rays are converted from a physical wave into a chemical and electrical message to be interpreted by the brain. This process is called phototransduction. In the sensory retina, there five main cell types and nine layers involved in this process. The sensory retina is an optically clear structure. For phototransduction to begin, an image must pass through the anterior blood supply and every layer of the sensory retina until the image finally reaches the photoreceptor layer. The photoreceptor layer is composed of rods and cones. There are roughly 120 million rods in the adult retina. These cells allow us to see the difference between light and dark. Rods are utilized for night vision and low lighting conditions. There are 6 to 7 million cones in the adult eye. Cones are only utilized for day or brighter conditions. These cells are specialize for color detection. ...

The main purpose of the front half of the eye is to focus a clear image on the retina. The next step in the process of vision is to convert that visual information (light rays) into a chemical message for the brain to process. However, before the image reaches the retina, it must first pass through a jelly-like substance called the vitreous. The vitreous fills most of the volume of the eye. It is mostly composed of water, but can also contain salt, sugar, a collagen called vitrosin, hyaluronic acid and other various proteins. When all these components are spaced out uniformly the vitreous remains clear and images pass on through to the retina undisturbed. With time more water concentrates in the lower portion of the eye. This leaves more proteins in contact with one another in the superior portion of the eye. The positive and negative charges of the molecular components of these proteins attract one another and result in the various proteins clustering together. This clustering cre...

My favorite part of each eye exam is getting the slit lamp (microscope) out and studying the various structures of a patient's eyes. The eye is a structure with many beautiful features. Each component of the eye plays a role in capturing images from the external environment and preparing that visual information for its journey through the brain. The first structures examined are the eyelids and eyelashes. These structures work to protect the eye from debris in the air and reset the tear film with each blink. A major contributor to our natural tears, the meibomian glands, are located just behind the eyelashes. Our major concern when looking at the eyelid are various skin cancers (basal cell carcinoma, squamous cell carcinoma, sebaceous gland carcinoma). Past the eyelids the tear film is observed. The tear film lubricates and protects the front surface of the eye, the cornea, and plays a vital role in keeping images clear on the way to the retina. The tear film is composed of thr...