Vision Problems: Contact Lenses vs. Glasses and Keratoconus Concerns

Q: Vision Problems: Contact Lenses vs. Glasses and Keratoconus Concerns

Hello： There may be differences in the prescription between contact lenses and glasses for several reasons： 1. <br>Different fitting methods： Contact lenses are typically fitted directly on the cornea, while glasses are fitted at a distance in front of the eyeball. <br>Since the

Vision examination issues

I recently visited an ophthalmologist and found that my vision with contact lenses is 0.8 and 0.9, while with regular glasses, it is only 0.4 and 0.5.
The axial length of my eyes was measured, but the doctor did not assess the true degree of astigmatism.
The doctor mentioned that there has been a significant increase in pseudomyopia.
Normally, the axial length increases by only 0.1 over three months, and there was no comment on astigmatism.
However, I have noticed that even when wearing contact lenses at night, my vision remains blurry, and I do not feel the clarity of 0.8 or 0.9.
Both glasses and contact lenses were prescribed at the same time, so why is it that my vision with contact lenses is better, even when squinting, compared to the glasses, which only provide 0.4 and 0.5? Additionally, my eyes seem to tire more easily than before.
Could this indicate an undiagnosed condition such as keratoconus? Also, does keratoconus affect axial length? Can keratoconus be detected through axial length measurements?

Niming, 10~19 year old female. Ask Date: 2024/04/20

Dr. Gao Pilin reply Ophthalmology

Hello: There may be differences in the prescription between contact lenses and glasses for several reasons: 1.
Different fitting methods: Contact lenses are typically fitted directly on the cornea, while glasses are fitted at a distance in front of the eyeball.
Since the curvature of the cornea differs from that of the anterior segment of the eye, the prescriptions for contact lenses and glasses may vary.
2.
Different lens materials: The materials used for contact lenses and glasses can differ, potentially affecting the refractive index of light and thus impacting the vision correction effect.
3.
Different wearing habits: The way contact lenses and glasses are worn can lead to different visual perceptions for the wearer.
In your case, since you did not undergo a cycloplegic refraction, it is not possible to determine the reason for the difference in prescription between your contact lenses and glasses.
It is recommended that you visit an ophthalmologist again for a cycloplegic refraction to obtain a more accurate prescription.

Keratoconus is a condition characterized by abnormal curvature of the cornea, leading to symptoms such as blurred vision, astigmatism, and glare.
If you have recently experienced symptoms like blurred vision or eye fatigue, it is advisable to return to an ophthalmologist for a detailed examination to rule out the possibility of keratoconus.
Keratoconus can cause changes in axial length, but this is not absolute.
In the early stages of keratoconus, there may be no significant change in axial length.
As the condition progresses, the axial length may gradually increase.
As for whether keratoconus can be detected through axial length measurement, this is not a common method.
Axial length is usually associated with myopia and is rarely used for diagnosing keratoconus.
Diagnosing keratoconus typically requires more precise ophthalmic examinations, such as corneal topography.

In addition to keratoconus, other diseases or factors may also cause the symptoms you are experiencing, such as: 1.
Dry eye syndrome: This can lead to symptoms like dryness, fatigue, and blurred vision.
2.
Eye strain: Prolonged use of the eyes can cause muscle fatigue, resulting in blurred vision.
3.
Other eye diseases: Certain other eye conditions, such as diabetic retinopathy or glaucoma, may also lead to blurred vision.
It is recommended that you undergo a comprehensive examination with an ophthalmologist to determine the diagnosis.

Reply Date: 2024/04/20

More Info

Understanding vision problems, especially when it comes to the differences between contact lenses and glasses, can be quite complex. Your situation, where you experience better vision with contact lenses (0.8 to 0.9) compared to glasses (0.4 to 0.5), is not uncommon and can be attributed to several factors.

Firstly, the difference in visual acuity between contact lenses and glasses can be due to the way each type of correction interacts with your eyes. Contact lenses sit directly on the eye's surface, providing a wider field of view and reducing the distortion that can occur with glasses, especially if the prescription is strong or if there is a significant amount of astigmatism. Glasses, on the other hand, are positioned away from the eye, which can lead to some optical distortions, particularly at the edges of the lenses. This is especially true if the frames are not well-fitted or if the lenses are not properly aligned with your pupils.

The fact that you are experiencing blurred vision at night, even with contact lenses, could indicate a few potential issues. One possibility is that your contact lens prescription may need to be adjusted, especially if you have developed a higher degree of myopia or astigmatism. Additionally, if you are experiencing eye fatigue, it could be a sign of overuse or strain, particularly if you spend long hours in front of screens without adequate breaks.

Regarding your concern about keratoconus, this condition is characterized by a progressive thinning and bulging of the cornea, which can lead to irregular astigmatism and visual distortion. While keratoconus can sometimes be detected through standard eye exams, it may not always be evident without specialized testing, such as corneal topography. This test maps the curvature of the cornea and can help identify irregularities that suggest keratoconus.
As for the relationship between keratoconus and axial length, keratoconus does not directly affect the axial length of the eye. However, individuals with keratoconus may experience changes in their refractive error, which can sometimes be associated with changes in axial length over time. It’s important to note that while axial length measurements can provide insights into the overall structure of the eye, they are not definitive for diagnosing keratoconus.

If you suspect that you may have keratoconus or if you are experiencing significant visual disturbances, it would be prudent to consult with an eye care professional who specializes in corneal diseases. They can perform the necessary tests to evaluate your corneal health and determine the best course of action.

In the meantime, to alleviate eye fatigue, consider implementing the 20-20-20 rule: every 20 minutes, take a 20-second break and look at something 20 feet away. This can help reduce strain from prolonged screen time. Additionally, ensure that your contact lenses are properly fitted and that you are following good hygiene practices to avoid any potential complications.

In summary, the differences in visual acuity between your contact lenses and glasses can be attributed to several factors, including lens positioning and potential prescription adjustments. If you have concerns about keratoconus or other underlying conditions, seeking a comprehensive evaluation from an eye care specialist is essential. Regular check-ups and appropriate lens adjustments can significantly improve your visual comfort and clarity.

Similar Q&A

Troubles with Contact Lenses: Seeking Advice for Discomfort and Dizziness

I normally wear glasses with a prescription of over -800 and astigmatism of around -200. Due to an incident while swimming, I lost my glasses, so I temporarily started wearing my friend's disposable contact lenses with a prescription of -750. I've been wearing them for ...

Dr. Zhang Yuhua reply Ophthalmology
Wearing improperly fitted contact lenses can lead to various issues. If the curvature is incorrect, or if the lenses are too tight or too loose, it can cause corneal hypoxia or a foreign body sensation. Dry eye conditions can also result in similar symptoms. It is advisable to un...

Effective Solutions for Myopia in Adults: Contact Lenses vs. Laser Surgery

Hello, Doctor. I started wearing orthokeratology lenses at the age of 16 and stopped wearing them last year when I turned 25 after getting a new pair. During the fitting for the new lenses, the ophthalmologist mentioned that orthokeratology lenses are not as suitable for adults a...

Dr. Cai Wenyuan reply Ophthalmology
It is recommended to wear regular glasses, as wearing contact lenses for too long can increase the risk of corneal infections.

Managing Vision Discrepancies in Cataract and Glaucoma Patients

Hello, Doctor He: I had cataract surgery on my right eye two weeks ago. I originally thought I could use contact lenses to address the vision disparity. However, I later learned that glaucoma patients are not suitable candidates for contact lenses. Currently, my left eye has a my...

Dr. He Jianxian reply Ophthalmology
Hello Urbancrab: If you cannot wear contact lenses, then the only option left may be cataract surgery. A significant disparity in vision can also be an indication for surgery, for your reference. Dr. He Jianxian, Ophthalmology Department, Nantou Hospital.

Understanding Amblyopia: Genetic Factors and Contact Lens Concerns

I am not sure if amblyopia is hereditary. My mother has it, and I also have it. My mother said it might have been passed down to me, which is why there is a significant difference in the prescription between my left and right eyes. My left eye is noticeably less clear than my rig...

Dr. Xie Wenzhen reply Ophthalmology
Hello, Miss: Thank you for your inquiry. I would like to respond to your question and provide the following suggestions: What is your best corrected vision with glasses? If your corrected vision is 0.8 or above and you are currently 21 years old, you should not be overly concerne...