General Information

 
Getting to know your Eye Back to top
 
The human visual system like a camera: there is a lens system (Cornea and Crystalline Lens) that captures the rays of light coming from objects, which focuses this rays of lights onto a film (Retina). This film is connected to a cable (Optic Nerve) which processes the images and transmits them to a computer that interprets them (The Brain)
 
The combination of all parts of the system is what provides us the ability to see the world around us.
 
 Here is a brief description of the most important parts:
 
The Cornea is the clear, dome shaped front surface of the eye. It has the thickness of a credit card. It covers the iris, which is the colored surface of the eye. Rays of light pass through and are focused by the cornea before they enter the eye. The cornea is the most important component of the eye’s optical system.
 

The Crystalline Lens is a biconvex shaped lens inside our eye that allows us to focus objects sharply onto the retina. In young people, the lens has the ability to modify its shape and adjust to different distance always providing a sharp image to the retina. As we age, the lens becomes less elastic and less able to change shape, loosing its ability to change power. This results in blurred vision at nears distances, and it is called Presbyopia. If it becomes clouded it interferes with your vision. This is a cataract.
 

The Aqueous Humor is the fluid that fills the anterior part of the eye, between the crystalline lens and the cornea. It is composed of nutrients that nourish the innermost cells of the cornea. It is produced inside the eye and drained by a very specialized structure inside the front part of the eye. When there is an imbalance between production and drainage of aqueous humor, the pressure inside the eye increases and Glaucoma occurs
 

The Vitreous is the Jelly-like substance that fills the back of the eye. As we age, it becomes less jelly-like and as is becomes liquefied there are pockets of liquid that contain clumps of gel floating around. We can see this clumps of vitreous, and they are called Floaters.
 

The Retina is the back layer of the eye that contains the light-sensing cells that will receive the images that we see in the world around us, and send this information to the Optic Nerve, which will send the images to our brain where we interpret them.
 

The Macula is the area of the retina that perceives central vision. It contains the highest concentration of high contrast visual acuity cells. It is the most important area of vision within the retina
 

About your Glasses Prescription 
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The Prescription in your glasses allows your visual system to focus sharp images onto your retina when specific features in your eye anatomy make it difficult. There are three reasons why you would need a prescription:
 

 
Myopia (Nearsighted) means that your visual system is too powerful and focuses a sharp image before it reaches your retina. A pair of Myopic Spectacles will return the sharp image back onto your retina.

Hyperopia (Farsighted) means that your visual system is too weak; therefore a sharp image is focused behind your retina. A pair of Hyperopic spectacles will return the sharp image to your retina.

 
Astigmatism means that the shape of your cornea is not spherical, therefore there are two images focusing at different distances from your retina (this is why it looks like shadows behind the objects). A pair of cylindrical spectacles will return both images to the same point on your retina.
 
Many times people have a combination of either Myopia or Hyperopia with Astigmatism, and both prescriptions can be combined in your spectacles to achieve sharp vision.
 
 
What is Presbyopia? Back to top
As we age, the lens becomes less elastic and less able to change shape, loosing its ability to change power. This results in blurred vision at nears distances, and it is called Presbyopia
 
Patients who have perfect distance vision without spectacles begin to notice these changes at about 45 years old.   However, patients who are nearsighted and require glasses to see well at a distance can see very well at near, and they experience symptoms of presbyopia much later in life.
 
For patients with good distance vision that are experiencing presbyopia, reading glasses are recommended. These can be purchased over the counter in pharmacies and grocery stores, or they can be custom made in an optical shop.  For patients who also need a prescription for distance, Bifocal Spectacles are an option for spectacles: in these, the top part of the lens contains the prescription for distance vision and the bottom part contains the prescription for reading or near activities. Trifocals are a pair of spectacles that contain a prescription for distance at the top, followed by a prescription for intermediate vision in the middle and a prescription for near vision at the bottom. Progressive Bifocals have a gradual progression between the distance correction at the top and the near correction at the bottom with no visible line in the glass
conditions.
 
Our optical shop has a full line of options for treating all of these conditions and a wide variety of great looking frames.
 


About Contact Lenses Back to top
Depending on your lifestyle and the health of your eyes, contact lenses may provide a safe and effective way of achieving spectacle independence when used with proper care and maintenance.
 
Contact Lenses are thin, clear disks of plastic that contain your prescription and coat your cornea floating on the tear film on the surface of the eye. They are used to correct the same conditions than glasses correct (Myopia, Hyperopia, Astigmatism and Presbyopia).

Blended Vision or Monovision contact lenses are another option for those who want to avoid the need for reading glasses in their presbyopic years. In this technique, one eye is corrected for distance (distance eye) and the other eye is left intentionally slightly nearsighted (near eye), providing a sharp near vision. It can only be applied to Contact Lens wearers, since the visual system is unable to adapt to the difference in prescription with spectacles. Blended Vision or Monovision is another option for those who want to avoid the need for reading glasses in their presbyopic years. In this technique, one eye is corrected for distance (distance eye) and the other eye is left intentionally slightly nearsighted (near eye), providing a sharp near vision. It can only be applied to Contact Lens wearers, since the visual system is unable to adapt to the difference in prescription with spectacles; but it can also be reproduced when programing the target prescription after Refractive Srugery or Cataract Surgery. There is typically a period of adaptation and vision is not as sharp as it would be with both eyes corrected for the same distance, but this is the compromise to achieve independence from spectacles. Eventually, the brain may learn to rely on the distance eye for distance tasks, such as watching TV, and on the near eye for near tasks such as reading and sewing. Some people are never able to adjust to blended vision so not everyone is a good candidate. Successful adaptation requires motivation, flexibility and a lifestyle that does not demand extreme visual acuity sharpness or extreme depth perception for daily activities.
 
There are different types of contact lenses:
 

Hard Contact Lenses or Rigid Gas Permeable Contact Lenses combine plastics with other materials to hold their shape while providing free flow of oxygen through the lens to the cornea. They may be the best choice for patients with irregular astigmatism that a soft lens will not be able to correct.
 
Soft Contact Lenses are the choice of the majority of patients because of their comfort and greater number of available options, which include

  • Daily Wear: removed every night and replaced for a new pair on an individualized schedule.
- Bi-Weekly
- Monthly
-     Disposable wear: more convenient, replaced by a new pair daily.
 
Our technicians and doctors can help you with contact lens options that are available.

 
What are Floaters? Back to top
As we age, the gelatinous vitreous becomes less jelly-like and as is becomes liquefied pockets of liquid are formed, which contain clumps of gel floating inside. We can see these clumps of vitreous as dark shadowy spots moving in our vision, so we call them Floaters.
 
Floaters can be a completely benign process associated with aging. However, as the vitreous becomes liquefied, it moves away from the retina and it can pull on it. As this happens, the retinal cells are stimulated and this is perceived as flashes of light in the peripheral portions of the visual field. This traction on the retina increases the risk of Retinal Detachment,which, although uncommon, is a serious condition that needs prompt attention. Similarly, as the vitreous separates from the retina it can break the small retinal vessels and create a Vitreous Hemorrhage or Hemorrhagic Vitreous Detachment, This bleeding is reabsorbed with time and visual acuity is usually restored. For any symptoms like these you need to be evaluated thoroughly by our eye doctors to rule out the presence of tears or breaks in your retina, which can increase the risk of Retinal Detachment.

 

Some important points about applying your drops Back to top
When applying eye drops it is normal that part of the drop falls out of the eye. A drop is 150 micro liters, and the eyelid can only retain 30 micro liters. Also part of that is drained through the lacrimal system (punctum) in the inner corner of your eyelid margins.
 
The best way to apply drops is to tilt your head back, pull your lower eyelid down and apply one drop in the sac formed between your lower eyelid and your eyeball.
When applying more than one drop, wait at least five minutes between drops. Otherwise you will sweep one out with the other. For glaucoma drops we recommend that you close your eyes for a period of three minutes to enhance absorption and maximize effectiveness of the medication.