Author - Melody She (Optometrist)
Eye strain or asthenopia is one of the most common complaints the optometrist hears while consulting in everyday practice. Patients come in with non-specific symptoms saying:
"My eyes feel tired....."
"I feel eyestrain after....."
"I get headaches after...."
"I feel tired after....."
So what exactly is asthenopia? This is when the patient experiences a vast range symptoms such as ocular fatigue and discomfort, pain in or around the eyes, headaches and occasionally blurred and double vision simply from using the eyes. Usually this is precipitated by copious amounts of prolonged computer or close work.
Asthenopia can be classified as internal or external; internal asthenopia is when the person feels strains and aches inside the eye, and external asthenopia consists of dryness and irritation felt on the front of the surface of the eye. Internal asthenopia can be caused by uncorrected refractive errors, vergence anomalies, heterophorias as well as accommodative dysfunctions. External asthenopia are mainly related to the conditions in the viewing environment such as lighting, poor image quality, flickering stimuli and dry eye.
With the vast amounts of social media, information technology and smart phone use, it's not surprising how much the frequency of asthenopia increases in everyday practice. As optometrists we identify the issues that are causing the patients asthenopic symptoms and form treatment plans subsequently.
When a person focuses on a near object or reads something close to them, the eye undergoes accommodation. Accommodation is when the eye itself changes optical power to maintain a clear image to focus light onto the back of the eye. It does this by using the ciliary body to change the shape of the lens in the eye.
If the person has a simple uncorrected refractive error such as hyperopia (long-sightedness) or astigmatism, the symptoms can be treated fairly easily with a pair spectacles for use at near, which the optometrist will calculate in the eye examination.
Usually by the time the patient presents in an eye exam however, some sort of accommodative dysfunction or stress has developed because of the prolonged uncorrection. In this case a low addition power as well as the refractive error is helpful to relieve symptoms. Some examples of lenses to use would be Hoya Dynamic Sync or Carl Zeiss Sola Access lenses.
The environment where the patient is everyday has a large impact on the person's external asthenopic symptoms. Making sure the patient's close work is in a comfortable location and that the light sources are good is not always possible in an office type or study type environment. In this case the patient may rely solely on the optometrist's treatment to relieve his or her symptoms.
Simple environmental changes such as keeping air-conditioning and heating rooms minimally can have a positive impact on the person's ocular surface. Dry eye symptoms are usually underestimated in the patient's treatment plan, but small changes to relieve dry eye such as ocular lubricants, omega 3 supplementation and eyelid hygiene and massages can have unprecedented effect on the patients comfort and asthenopic symptoms.
Asthenopia is extremely common in today's high smartphone use environment. Optometrists help to identify the causes of the patient's asthenopic symptoms and should come up with treatment plans to alleviate the majority of the symptoms. Follow up is always recommended incase the symptoms do not completely subside, in which further referral may be necessary to help with more difficult or underlying issues.
By Melody She.
Optometrist at 1001 Optical.
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