Your eyeglass prescription contains several numbers that may look confusing, but each one plays an important role in ensuring you get the correct lenses. Here’s a breakdown of the main components:

• OD and OS: OD (Oculus Dexter), refers to your right eye and OS (Oculus Sinister) refers to your left eye.
• SPH (Sphere): It indicates the strength of the lens needed to correct nearsightedness or farsightedness. A minus sign (-) means you are nearsighted, and a plus sign (+) means you are farsighted.
• CYL (Cylinder): It measures the lens power needed to correct astigmatism, if you have any. Otherwise, this field will be left blank.
• D.S. (Diopter Simplex): An eye dr. may write DS on an Rx in the Cylinder (CYL) field if no astigmatism correction is needed.
• AXIS: The axis number tells you the angle at which the astigmatism correction should be positioned on the lens. It’s measured in degrees from 1 to 180. Unless it's D.S on Cylinder, AXIS will be 0/Null. 
• ADD (also NV-ADD, Near Vision ADD): This is the additional magnifying power for presbyopia correction on a multifocal Rx, can be used for bifocal or progressive lenses.
• PD (Pupillary Distance): It refers to the distance between your pupils in millimeters. It is used for manufacturers to ensure the optical center of your lenses aligns with your pupils that you can see well through the glasses.
• Prism: Prism indicates the amount of prismatic power, measured in diopters, needed to compensate for any alignment problems in your eyes.
• Base: This column indicates the direction of a prism by noting the relative position of its thickest edge, which will either appear in a column of its own or be included in the prism column. The orientation of the prism will be indicated by ‘BU’ (base up), ‘BD’ (base down), ‘BI’ (base in), or ‘BO (base out).

      If you can’t make sense of your eyeglass prescription, you’re not alone. Click here for How to Read My Prescription Example to help you navigate yours.

If you’re unsure how to interpret your prescription, feel free to contact us for assistance!

PD (Pupillary Distance) is the distance between the centers of your pupils, measured in millimeters. It’s an essential measurement for making sure your eyeglass lenses are properly aligned with your eyes.

Here's why it's important:

• Lens Alignment: PD ensures that the optical center of each lens sits directly in front of your pupils. If the PD is incorrect, the lenses won’t align properly, which can cause eye strain, headaches, or blurry vision.
• Clear Vision: Accurate PD helps your lenses focus light correctly for clear and comfortable vision, especially for prescription glasses, progressive lenses, or reading glasses.

If you're unsure of your PD, you can ask your optician to measure it, or you can measure it yourself at home using the ruler we provide and a mirror. Proper PD measurement is crucial for optimal vision and comfort!

ADD or NV-ADD (Near Vision Add) refers to the additional magnifying power required for reading or seeing objects up close. It is commonly included in prescriptions for people who have presbyopia, a condition where near vision becomes more difficult as you age.

Here's what ADD means:

• For Multifocal/Bifocal Lenses: The ADD value provides the extra strength needed in the lower part of the lens for tasks like reading or using a phone, while the upper part of the lens is for distance vision.
• Single Vision Reading Glasses: If you wear reading glasses, the ADD value helps create lenses that only correct near vision.

The ADD value is usually the same for both eyes and ranges from +0.50 to +3.00, a few can go up to +4.00, depending on the level of magnification needed. If you see NV-ADD on your prescription, it refers specifically to the correction for near vision.

Prism is a special prescription value used to correct eye alignment issues, such as double vision or strabismus (misaligned eyes). Prism helps direct light into the correct part of your eyes so that your brain can merge the images from both eyes into a single, clear picture.

Here’s what the prism value means and how to understand it:

• Prism Value: This is measured in diopters and indicates the amount of correction needed to align your eyes properly. It may be specified in vertical (up or down) or horizontal (in or out) directions.
• Base Direction: The prism value is always accompanied by a base direction (Base Up, Base Down, Base In, or Base Out), which tells the lab where to apply the prism in the lens. For example, "Base In" moves the image toward the nose, while "Base Out" moves it outward.

How to Fill Prescriptions with Prism Correction:

1. Provide the Prism Value: Make sure to include the exact prism diopter number and base direction for each eye. Your prescription will indicate this clearly.
2. Choose a Reliable Provider: Not all optical labs handle prism correction, so it’s essential to choose an eyewear provider that can accurately manufacture lenses with prism correction.

If you have prism in your prescription, it's important to ensure the lenses are custom-made with precision to avoid eye strain or discomfort. At Dilly Dollar Optical, we can assist with prism prescriptions—reach out if you need help!

Yes, we can! At Dilly Dollar Optical, we provide lenses that correct astigmatism.

Astigmatism occurs when the eye’s cornea or lens has an irregular shape, causing blurred or distorted vision at any distance. Prescriptions for astigmatism contain two specific values:

• CYL (Cylinder): This measures the strength needed to correct the astigmatism. The number indicates how much correction is needed for the uneven curvature of the eye.
• AXIS: This number, measured in degrees (1 to 180), indicates the orientation of the astigmatism correction. It specifies where on the lens the correction should be applied to properly focus light.

We can fill prescriptions with astigmatism corrections, ensuring you receive lenses that provide clear, comfortable vision. Simply provide your complete prescription, including both CYL and AXIS values, and we’ll handle the rest!

At Dilly Dollar Optical, we offer a wide range of lens powers to accommodate different vision needs. Below are the power ranges for the types of lenses we provide:

1. Single Vision Rx:

• Sphere (SPH): 0~-12.00

(Customization needed for -12.00 to -15.00 )

• Cylinder (CYL) (for astigmatism): Up to -6.00

2. Bifocal Rx:

• Sphere (SPH): 0~-12.00
• Cylinder (CYL) (for astigmatism): Up to -6.00
• ADD: Up to +3.50

3. Progressive Rx:

• Sphere (SPH): 0~-12.00
• Cylinder (CYL) (for astigmatism): Up to -6.00
• ADD: Up to +3.50

4. Prism Correction:

• Prism Diopter Range: Up to 5.00 diopters
• Base Direction: We can fill prism prescriptions with base directions including Base Up, Base Down, Base In, or Base Out.

If your prescription falls outside of these ranges, please feel free to contact us, and we’ll do our best to accommodate your needs.

If we are unable to fill your prescription, you can still purchase our frames with an extra 15% off. Feel free to contact us with any questions.

Bifocal lenses are special types of eyeglass lenses designed to correct both distance vision and near vision in a single lens. They are commonly prescribed for people with presbyopia, a condition where near vision becomes more difficult with age.

Here’s how bifocal lenses work:

• Two Distinct Zones: Bifocal lenses have two different optical powers.
• Visible Line: Unlike progressive lenses, bifocals have a visible line separating the two vision zones, which is noticeable when you look at the lens.

Bifocal lenses provide a practical solution for people who need help seeing both near and far without switching between multiple pairs of glasses. If you're interested in bifocals, we offer a wide variety of stylish frames to choose from at Dilly Dollar Optical!

Progressive lenses are advanced multifocal lenses designed to provide a smooth transition between different vision zones, correcting distance, intermediate, and near vision all in one lens—without the visible line found in bifocals.

Here’s how progressive lenses work:

• Seamless Vision: Progressive lenses offer a gradual change in lens power from the top to the bottom, allowing you to see clearly at all distances:
• No Visible Line: Unlike bifocals, progressive lenses have no visible dividing line between the different vision zones, making them more aesthetically pleasing and giving you a natural field of vision.

Progressive lenses are a great option for people who need multifocal vision correction and want a more seamless, stylish alternative to bifocals. We offer a range of progressive lenses at Dilly Dollar Optical to meet your vision needs!

Both bifocal lenses and progressive lenses provide a solution for people who need corrections for both myopia and presbyopia.

What Are Bifocal Lenses?

What are progressive lenses?

How to choose between bifocal lenses and progressive lenses can be determined by multi reason:

• Lifestyle Needs: If you frequently need to switch between seeing far away and up close, and you prefer a more natural vision experience, progressive lenses might be the better choice. If you mainly need glasses for specific tasks like reading and distance vision, and don’t mind the visible line, bifocals could work well.
• Aesthetic Preferences: If you prefer a more modern look without visible lines, progressive lenses are the way to go. Bifocals might be suitable if you don’t mind the traditional appearance.
• Adaptation and Comfort: Progressive lenses offer more comprehensive vision correction but may require a longer adjustment period. If you have difficulty adapting to new lenses, bifocals might be easier to get used to.

Ultimately, the choice depends on your personal vision needs, preferences, and lifestyle. If you need help deciding, our team at Dilly Dollar Optical can assist you in finding the best option for your needs!

Computer glasses are task-specific eyeglasses designed to reduce eye strain and provide clear vision while working at a computer. They are customized based on your prescription to offer the best visual comfort at the typical screen distance, usually about two feet away from your eyes.

What Do Computer Glasses Do?

The primary function of computer glasses is to help your eyes focus on digital screens more easily and prevent the symptoms of Computer Vision Syndrome (also called digital eye strain). Staring at a screen for long periods can strain the muscles in and around your eyes due to two main reasons:

• Distance: Computer screens are typically positioned at an intermediate distance, which makes your eyes work harder to maintain focus.
• Pixels: Screens display content using tiny pixels, and if the resolution is low, your eyes have to exert more effort to see clearly.

Computer glasses are specially tailored to correct your vision at this intermediate distance, reducing the strain on your eyes and helping you focus comfortably on the screen.

Benefits of Computer Glasses

By reducing eye muscle fatigue, computer glasses can help prevent the symptoms of digital eye strain, which include:

• Headaches
• Tired, sore eyes
• Blurry vision
• Dry, burning, or watery eyes
• Neck, shoulder, and back pain
• Eye twitching or red eyes

At Dilly Dollar Optical, we offer customizable computer glasses to help make your screen time more comfortable and productive!

What Do Lens Index Numbers Mean?

Lens index numbers refer to the refractive index of a lens, which measures how efficiently the lens bends light. A higher index means the lens can bend light more effectively, allowing for thinner lenses while still providing the necessary correction for your vision.

What’s The Relationship Between Index Numbers And Lens Thickness?

• Lower Index Lenses (1.50 - 1.56): These lenses are thicker and are suitable for people with lower prescriptions.
• Mid-Index Lenses (1.57 - 1.61): These lenses are moderately thinner and lighter, designed for people with mild to moderate prescriptions.
• High Index Lenses (1.67 - 1.74): These lenses are thinner and lighter, ideal for those with stronger prescriptions. The higher the index number, the thinner the lens will be, making it less bulky and more comfortable.

Choosing the right index depends on your prescription strength and personal preferences for thickness and appearance.

The Lens Index number (1.56, 1.61, 1.67, or 1.74) refers to the degree of refraction the lens provides, indicating how much the light that enters the lens is refracted (bent) as it passes through the lens.

Lens Index is also related to the thickness of the lens. The higher the index, the thinner the lens will be.

High index lenses are thinner, more powerful lenses. They're lightweight and stylish, but are mostly reserved for those with higher vision correction needs.

Recommend Index Number

Lens Index Overview

Image	Lens Index	Features	SPH
	1.56 INDEX LENS	For people with moderately-strong prescriptions. Thinner and lighter than standard lenses.	-0 to -3.00
	1.60 INDEX LENS	Stylish and extra-thin. Great choice for stronger prescriptions.	-3.00 to -5.00
	1.67 INDEX LENS	Extremely thin. Good choice for extra-strong prescriptions.	-5.00 to -8.00
	1.74 INDEX LENS	As thin as possible. Best for the highest prescriptions.	-7.00 and above

While most prescriptions are compatible with more than one specific index, it's up to you to decide which one fits your personal needs!

Aspheric lenses have a more complex, non-spherical surface design compared to traditional spherical lenses. This design allows them to be thinner, flatter, and lighter, while still providing clear vision correction. Aspheric lenses are especially beneficial for people with higher prescriptions, as they reduce the bulkiness and distortion often seen with thicker lenses.

What’s The Difference Between Spheric Lenses And Aspheric Lenses?

Aspheric lenses offer a sleeker, thinner look with improved vision clarity, while spherical lenses tend to be thicker and can distort peripheral vision, particularly for higher prescriptions.

The lenses we offered at Dilly Dollar Optical are all aspheric lenses that give you a better vision and more comfortable experience.

At Dilly Dollar Optical, we offer a variety of lens coatings to enhance your lenses' durability, comfort, and protection:

1. Anti-Scratch Coating: Protects your lenses from everyday scratches, helping them last longer and maintain clear vision.

Anti-Scratch Coating is applied to all lenses provided by Dilly Dollar Optical.

2. UV Protection Coating: Blocks harmful UV rays, providing full protection for your eyes when outdoors, similar to sunglasses.

UV Protection Coating is applied to all lenses provided by Dilly Dollar Optical.

3. Anti-Reflective (Anti-Glare) Coating (AR Coating): Reduces glare by absorbing and redirecting reflected light. This allows more non-reflected light to pass through, leading to fewer visual disturbances. Unlike reflective lenses with mirror-like finishes, anti-reflective coatings are transparent with a very faint green or blue tint.

Anti-reflective coating is not a necessity, however, if you have symptoms of eye strains, spend a lot of time in front of a computer or constantly drive at night or drive long-distance, you may need to consider add an AR coating to your prescription.

4. Blue light Coating: Blue Light Coating filters the harmful high energy blue light to reduce accumulated potential damage to the eyes while it allows good blue light to pass through the lens for increased visual acuity and clarity.

Blue Light Coating is an optional addition to all the lenses in Dilly Dollar Optical.

These coatings can be combined to provide optimal protection and clarity for your specific needs.

What Are Photochromic Lenses?

Photochromic lenses are special lenses that automatically adjust their tint in response to changing light conditions. They darken in bright sunlight to reduce glare and UV exposure, and return to a clear or lightly tinted state indoors or in low-light conditions.

Lens Tint

Photochromic lenses typically have a base tint that can range from nearly clear to lightly tinted when not exposed to UV light. When exposed to UV light, such as sunlight, the lenses darken to a shade that varies based on the intensity of the light.

Percentage of Darkness in the Tints

The percentage of darkness in photochromic lenses can vary depending on the specific lens and brand. Generally:

• Lightest Tint: Approximately 10-20% darkening when exposed to UV light.
• Medium Tint: Around 30-50% darkening, suitable for moderate light conditions.
• Darkest Tint: Up to 70-80% darkening, providing significant protection in bright sunlight.

Photochromic lenses offer convenience and protection by adjusting their tint automatically, making them versatile for varying lighting conditions.

Polarized lenses are designed to reduce glare from reflective surfaces, such as water, snow, and roads. They contain a special polarizing filter that blocks horizontally polarized light, which is responsible for causing glare.

How Do Polarized Lenses Work?

• Polarization Filter: The lenses have a vertical polarizing filter that only allows vertically oriented light to pass through. This blocks the horizontally polarized light that causes glare.
• Reduced Glare: By filtering out glare, polarized lenses provide clearer vision and reduce eye strain, making them particularly useful for activities like driving, fishing, and skiing.
• Enhanced Contrast: They improve contrast and visual clarity, allowing you to see more details and colors more vividly.

Polarized lenses are ideal for anyone who spends a lot of time outdoors or in situations where glare can be problematic. They enhance visual comfort and safety by minimizing glare and improving overall vision quality.

Polycarbonate lenses are a type of high-impact-resistant eyewear made from a lightweight, durable material known as polycarbonate. They are known for their strength and safety features, making them a popular choice for various applications.

Key Characteristics of Polycarbonate Lenses:

• Impact Resistance: Polycarbonate lenses are highly resistant to impacts and can withstand significant force, making them ideal for safety glasses and sports eyewear.
• Lightweight: These lenses are lighter than many other lens materials, which increases comfort, especially for people who wear glasses for extended periods.
• UV Protection: Polycarbonate lenses naturally block 100% of harmful UV rays, providing built-in protection for your eyes.
• Optical Clarity: They offer good optical clarity, though they may not be as clear as some higher-end lens materials.
• Scratch Resistance: While inherently tougher than standard plastic lenses, polycarbonate lenses typically come with an additional scratch-resistant coating to enhance durability.

Polycarbonate lenses are a practical choice for those needing durable, impact-resistant eyewear with built-in UV protection. They are especially suitable for children, active individuals, and those who require safety glasses.

Mirrored lenses are eyewear lenses coated with a reflective mirror-like finish on the outside. This coating gives the lenses a distinctive, shiny appearance and offers several functional benefits:

Key Features of Mirrored Lenses:

• Glare Reduction: The reflective coating reduces the amount of light that passes through the lens, helping to minimize glare from bright light sources, such as sunlight reflecting off water or snow.
• Enhanced Privacy: The mirror coating makes it difficult for others to see your eyes, providing a level of privacy while wearing the glasses.
• Stylish Appearance: Mirrored lenses are often chosen for their fashionable and bold look, making them popular in both sports and fashion eyewear.
• UV Protection: Many mirrored lenses also have built-in UV protection to safeguard your eyes from harmful ultraviolet rays.

Mirrored lenses are a great choice for outdoor activities and sports where glare reduction and eye protection are important, as well as for those seeking a trendy, stylish look.

Night driving lenses are designed to improve visibility and reduce glare while driving at night. They address specific challenges associated with low-light conditions and headlights from other vehicles.

Key Features of Night Driving Lenses:

• Anti-Glare Coating: They typically include a special coating that helps reduce glare from oncoming headlights and streetlights, making nighttime driving more comfortable and safer.
• Enhanced Contrast: These lenses improve contrast and depth perception, helping drivers see details more clearly in low-light conditions.
• Yellow Tint: Many night driving lenses have a subtle yellow tint that can help to enhance contrast and reduce the blueness of headlights, which can be distracting at night.

Night Driving Clip-Ons

Night driving clip-ons are attachable filters that can be clipped over your regular prescription glasses. They are designed to provide similar benefits as dedicated night driving lenses but offer flexibility by fitting over existing eyewear.

• Easy Attachment: Clip-ons can be easily attached and removed as needed, providing an economical and convenient solution for improving night driving vision.
• Adjustable Fit: They come in various sizes and shapes to fit different types of glasses.

Both night driving lenses and clip-ons aim to enhance your visibility and safety while driving at night by reducing glare and improving contrast.

Blue light is a color in the visible light spectrum with a very short wavelength and therefore produces a very high amount of energy compared to other visible light.

Before the advent of artificial light, blue light only exists within the visible spectrum of natural sunlight. However, artificial blue light emitted by every LED light can do more harm to human body, which may contribute to the causation of cancer, diabetes, heart disease, obesity as well as destroy the circadian thythm.

Blue Light and Sleep

Although everyone has slightly different circadian thythms, but the average is around 24 hours which aligned with the environment.

When sun rises, light come out, the human brains receive the signal to wake up, while night comes, darkness causes the body to produce melatonin(known as the sleep hormone), which makes us fall asleep and stay asleep.

Exposure to light in the darkness suppresses the release of melatonin as the light is the signal to keep you awake and alert. That is how light affects the circadian thythms and lower the quality of sleep.

While light of any kind can suppress the secretion of melatonin, blue light due to its short wavelength and high energy, does so more powerfully at night.

Wear Blue Light Filtering coated glasses if you have to look at screens at night. Dilly Dollar Optical provides you with all kinds of Blue Light Filtering coating classes to protect your eyes and your health.