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June 12, 2022 BlogPresbyopia

Vision is our main way of interacting with the world, and it can be debilitating when our vision deteriorates. Unfortunately, presbyopia – the gradual loss of ability to focus on nearby objects – is basically inevitable. Presbyopia affects nearly 25% of the world population; almost 2 billion people. People usually see symptoms in their 40s, but the path starts in childhood.

The exact cause of presbyopia is unknown, but the effects are well documented. The eye’s lens is the bit that changes shape, allowing us to focus at different distances. During childhood, the lens gradually becomes less flexible. Since it can’t change shape as easily, we stop being able to focus as rapidly and accurately. It gets more difficult to focus at close or mid-lengths. There are four broad methods suggested for increasing focal range, each with its own trade-off.

Changing focus over time is the first method. Think of it like having several pairs of glasses. When focusing on close things you might use readers. Different glasses may be used for mid-length, or distance viewing. This is what our eyes do naturally (when we’re young at least!). So far there are no pharmaceutical or implantable devices that can accomplish this. Using several glasses is a good – if bulky – approximation for millions of people, however.

Changing focus depending on where you look is the second method. Bifocals are the classic example. This solution is quick and convenient. There are downsides, however. Changing from near to mid-focus can be jarring, vision can be blurry, and eye strain occurs sometimes. One often overlooked issue is that bifocals can introduce other dangers, such as falls due to unfocused areas near the feet when walking.

Changing focus between eyes is an interesting method. With this approach, one eye is corrected for close vision, and the other stays focused at a distance. Each eye only focuses narrowly, but together you can see across a wide range. Even though this is easy to try by putting in only one contact lens, it can be hard to get used to and lead to a loss of binocular vision. Judging distances of objects may be more difficult with this method, and it can be uncomfortable for some people.

The final method is to increase the focal range across distances. This is an innovative method where the eyes are changed to have more in-focus at the same time. If you’ve ever had an eye exam where they dilate your pupils, this is the opposite. The pupils are artificially constricted. This extends your depth of field, making it easier to focus on things near and far at the same time! Some side effects may include a loss in quality and contrast, and a loss of low-light sensitivity. One of the big hurdles researchers have is the precision required to pull this off successfully. Methods to induce increasing focal range can be permanent, such as with implanted lenses; but mitigation of side effects may be easiest with special eye drops. Some of these eye drops are being tested currently in clinical trials.

With so many different angles to attack presbyopia, and volunteers helping with clinical trials, we may be looking at a universal treatment soon! 

Written by: Benton Lowey-Ball, B.S. Behavioral Neuroscience



Source:

Chang, D. H., & Waring, G. O. (2021). Presbyopia Treatments by Mechanism of Action: A New Classification System Based on a Review of the Literature. Clinical Ophthalmology (Auckland, NZ), 15, 3733.


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May 1, 2022 BlogGlaucoma

The eye is a fragile and carefully balanced organ. At the very front of the eye is a fluid-filled chamber called the anterior chamber. This is located between the clear cornea at the front and the pupil, where light enters the rest of the eye. The fluid that fills this area is called the aqueous humor. The aqueous humor is critically important for cleaning and bringing nutrients to the lens. It is like a clear version of blood. Another key job the aqueous humor performs is maintaining eye pressure.

The pressure in the eye needs to be maintained within a very specific range (12-22 mm Hg). Aqueous humor continuously flows through the front of the eye at a very slow rate (like blood, but slower). When the flow rate out of the eye gets disrupted, eye pressure increases.

Doctors call high eye pressure ocular hypertension. The major characteristic is increased eye pressure without other symptoms. When eye pressure causes damage to the optic nerve, we call it glaucoma. Glaucoma can occur in two ways, closed angle or open angle. Closed angle is sudden and a medical emergency. Open angle makes up almost all cases of glaucoma and is gradual in onset. Typical symptoms of open angle glaucoma are vision problems in the middle of sight. These can include trouble with reading, seeing faces, walking, and driving. Both types will cause permanent blindness if untreated.

Open angle glaucoma can happen to anyone, but is much more common with adults over 60 years old. Most cases are females, and black and Asian populations experience higher rates of the condition. There are several underlying reasons for open-angle glaucoma: vascular, anatomical, genetic, or immune. Because of this wide spread of causes, there are several risk factors:

  • Genetics / Family history
  • Diabetes
  • Extreme nearsightedness
  • Hypertension
  • Eye injury
  • Eye abnormalities
  • Steroid use
  • Smoking

Several treatments are available for glaucoma. These include surgical and medication-based treatments, and surgically implanted medications. The goal of all treatments is to increase the flow of fluid out, decrease the amount of fluid coming in, or to decrease the volume of the anterior chamber. Medications are quite effective when taken properly. Unfortunately, fewer than one third of patients adhere to doctor recommendations for glaucoma eye drops after a year. This is in spite of the condition being progressive in nature and leading to blindness. Effective implanted medication delivery systems may provide better outcomes for patients.

To get involved in the latest glaucoma research, contact our Nature Coast Crystal River office.


Sources:

Allison, K., Patel, D., & Alabi, O. (2020). Epidemiology of glaucoma: the past, present, and predictions for the future. Cureus, 12(11).

Li, F., Huang, W., & Zhang, X. (2018). Efficacy and safety of different regimens for primary open‐angle glaucoma or ocular hypertension: A systematic review and network meta‐analysis. Acta ophthalmologica, 96(3), e277-e284.

Robin, A. L., & Muir, K. W. (2019). Medication adherence in patients with ocular hypertension or glaucoma. Expert Review of Ophthalmology, 14(4-5), 199-210.


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January 7, 2020 BlogGlaucoma

Glaucoma is a common eye disease that can gradually steal your vision. The term glaucoma refers to a collection of eye diseases that damage the optic nerve. This damage can lead to permanent vision loss or even total blindness. Glaucoma is considered a major cause of blindness in the general population.

A major concern is that glaucoma often presents no early symptoms but continues to cause gradual, un-reversable damage. In most cases, glaucoma is diagnosed in people who are older than 40 but can still develop at an earlier age. An estimated 3.54% of adults between 40 and 80 years have been diagnosed with some type of glaucoma.

 

Causes Of Glaucoma

In most types of glaucoma, the eye’s drainage system becomes clogged so the intraocular fluid cannot drain. As the fluid builds up, it causes pressure to build inside the eye.  High pressure damages the sensitive optic nerve and results in vision loss.

 

People are more likely to develop glaucoma if they:

  • Are over the age of 40
  • Have a family history of glaucoma
  • Have high blood pressure, heart disease, diabetes, or sickle cell anemia
  • Are of African American, Irish, Russian, Japanese, Hispanic, Inuit, or Scandinavian descent
  • Take certain steroid medications such as prednisone
  • Have had an injury to your eye or eyes
  • Have high eye pressure (ocular hypertension)

 

Current Treatments Available

Unfortunately, there is not currently a cure for glaucoma. However, there are several therapies that can help reduce eye pressure and the rate of damage to the optic nerve. Current approved treatment options for glaucoma include eyedrops, oral medications, laser surgery, or microsurgery.

 

Clinical Research Advancements

New clinical trials for glaucoma are focused on more innovative ways to treat the disease. Researchers are studying everything from electric current stimulation to slow release eye implants to help find relief for patients with glaucoma.

You can help advance medical research by participating in a clinical trial! Contact any of our offices to see what clinical trials are enrolling today.

 

 

References:

https://www.aaojournal.org/article/S0161-6420(14)00433-3/abstract
https://www.mayoclinic.org/diseases-conditions/glaucoma/symptoms-causes/syc-20372839
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4927811/


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