3D Digital Eye Test & Progressive Lenses
Patama Cherdchu-kiatisakul, Ph.D.
Doctor of Optometry for ISOPTIK Personal Progressive Eyeglasses Center
Eye examination for eyeglasses is extremely important for eye health and quality of life, as uncorrected vision problems can affect daily life and work. Regular eye examination is a basic eye care that should not be neglected.
What is an eye examination for eyeglasses, and why is it important?
An eye examination for eyeglasses is the process of measuring vision values to select lenses suitable for the wearer. An optometrist or ophthalmologist uses specialized instruments to detect various vision problems such as farsightedness, nearsightedness, astigmatism, and determine the appropriate lens power. Accurate measurement will result in eyeglasses with the correct magnification power, providing clear vision, reducing eye strain, and preventing vision problems from worsening due to unsuitable eyeglasses.
The Importance of Choosing Eyeglasses Suitable for Vision Values
Appropriate eyeglasses not only help to improve vision clarity but also prevent eye health problems that may arise from using eyeglasses that do not match the vision values. If unsuitable eyeglasses are chosen, it may cause headaches, eye pain, or easy fatigue, especially for people with nearsightedness or farsightedness. Choosing the right eyeglasses is therefore crucial for clear and comfortable vision.
Symptoms indicating that you should get your eyes examined for new glasses :
Blurred vision at both near and far distances.
Headaches or dizziness after prolonged eye use.
Eye blurring or double vision.
Having to hold books or phones further away than usual.
Having to squint or rub eyes frequently to see clearly.
Frequent eye pain or fatigue.
Tendency to strain or move closer to the screen.
3D System Eye Examination for Eyeglasses
3D Computerized Eye Examination
ISOPTIK Personal Progressive Eyeglasses Center has successfully invented and developed a new top-end technology progressive lens fitting system with a 3D digital system that can analyze the binocular vision system and analyze eye usage behavior, calculating 360-degree vision values within just 40 minutes. This provides detailed information for designing, manufacturing, and fitting progressive lenses with new top-end technology that provides the sharpest vision at all distances in the most natural way. This helps the visual control center of the brain to not have to strain as hard as before, increasing the brain's efficiency in other areas of work, making one feel instantly energized, like being young again, and also preserving vision better.
Steps in Eye Examination
1. Start with measuring Visual Acuity (V.A.) V.A. refers to the ability to see. The V.A. is measured one eye at a time, starting with the right eye (covering the left eye), then the left eye (covering the right eye), and finally, both eyes open together. V.A. can be measured as unaided V.A. (without eyeglasses or contact lenses) to measure the natural vision ability without any correction, or V.A. with old glasses if the person being tested already uses eyeglasses, to measure the performance of the current glasses. The benefit of measuring unaided V.A. or V.A. with old glasses is to compare the visual ability before and after the eye examination to obtain the new, appropriate vision values.
2. After V.A. measurement, the next step is measuring the corneal curvature or finding the K value. Finding the K value allows us to estimate the astigmatism value and axis.
3. Start finding the vision value by the Objective method. This is the preliminary vision measurement where the person being tested does not need to answer anything. The examiner determines the vision value themselves using methods such as Retinoscopy or Autorefraction, measuring one eye at a time. Once the vision value is obtained, the next step is performed.
4. The Subjective vision value measurement is to find the most suitable vision value for each person being tested, requiring their participation by answering questions, which is divided into the following substeps :
Find the optimal vision value for each eye, starting with the right eye and covering the left eye. The first step is to find the best sphere value before finding the astigmatism value using the Red-green Test or Step-down method. Once the initial best sphere value is obtained, the astigmatism value and the most suitable astigmatism axis are found using the Jackson Cross Cylinder (JCC). After obtaining the most suitable astigmatism value and axis, the sphere value (nearsightedness or farsightedness) is refined again using the Red-Green Test or Step-down method to ensure the best possible vision in each eye while controlling against over-correction. Once the right eye is completed, the same steps are repeated for the left eye (swapping the cover to the right eye and opening the left eye). This yields the best vision value for each eye, and then we proceed to the next step of the eye examination.
- Finding the optimal vision value for binocular use. This step is crucial and indispensable because measuring one eye at a time with the other covered might cause different levels of accommodation in each eye (though we must measure one eye at a time first to understand the visual ability of each eye). When viewing with both eyes open, the control of accommodation is equal in both eyes. We find the most suitable vision value to make the vision of both eyes optimal and as close as possible using a slide with a polarized system. When looking with both eyes, the full slide image is seen, but in reality, half of this slide image is seen by the right eye and the other half by the left eye. This controls both eyes to see simultaneously and allows the separation and comparison of the vision of the two eyes to obtain the most suitable vision value for making the eyeglasses.
5. Measuring Binocular Vision Efficiency. Once the vision values are obtained, we must additionally check the efficiency of binocular vision, such as the ability to see 3D images using a slide that, when viewed through the lenses, appears as a 3D image with different levels of image depth. This tests how well the person being examined can distinguish image depth levels. The next check is whether the two eyes can perfectly align the image positions (Associated Phoria testing). The method involves the full slide image, where some parts are seen by the right eye and some by the left eye. When the person being examined looks at the slide with both eyes, they observe the position of the two parts of the image to see how the two parts relate—whether they perfectly connect or if the image positions are misaligned, and in which direction the misalignment occurs. This is to find the prism value that will shift the images to connect perfectly. This value is used when the person being examined has vision problems that are corrected by general prescriptive lenses but still do not see clearly (because the images seem not to overlap perfectly) or experience eye pain (because the eyes have to work harder than normal for the two eyes to work together) due to persistent binocular vision problems, which must also be corrected with these specific lenses.
6. After measuring distance vision ability, the next step is measuring near vision. This is typically measured at 40 cm to check if the person's accommodation system (automatic focus adjustment) can focus correctly when reading or working at this 40 cm distance. This is done using a near cross grid, which works by using lenses to split the images of the vertical and horizontal lines, causing one to fall before and the other after the retina. If the eye focuses the image precisely on the retina, the vertical and horizontal lines will be equally sharp. If the lines are not equally sharp, the lens will be adjusted until both lines are equally sharp. This gives us the lens value that helps the near image focus perfectly on the retina. Additionally, we use methods to find NRA (Negative Relative Accommodation) and PRA (Positive Relative Accommodation) to determine the range of accommodation ability to check if the accommodation system is within the normal range and can help find the suitable lens value for near viewing.
7. After obtaining both the general distance vision value and the vision value for reading, we put the obtained values into a trial frame so the person being examined can try wearing them in real-life conditions, walking around generally to check their adaptation and acceptance of the vision values. They also try reading at the actual working distance they use regularly to adjust the vision value for the final time before obtaining the value that will ultimately be used for making the actual eyeglasses.
How often should you get your eyes examined for new glasses?
Generally, it is recommended to have an eye examination at least once a year, even without any unusual symptoms. However, if unusual symptoms occur, such as blurred vision, eye pain, or frequent headaches, you should see an ophthalmologist or eye specialist immediately. This is because, in addition to getting an eye examination for new glasses, it is also a preliminary check of eye health to prevent diseases that could lead to vision problems becoming difficult to treat.
For those who wish to have their eyes examined for eyeglasses, you can consult your problems with experts and optometrists at ISOPTIK Eyeglasses Center, the Personal Progressive Eyeglasses Center. We have a team of expert optometrists and ophthalmologists ready to provide consultation, design, and detailed analysis of your eye usage, with Grand Master Bobi overseeing every step closely. This is to ensure you receive progressive eyeglasses that are comfortable to wear, meet your usage needs, and help enhance your quality of life, along with a maximum satisfaction guarantee of 180 days.
Free Consultation with Master Bobi: A World-Class Expert in 3D Bespoke Ultra individual progressive lenses. Call : 081-538-4200
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