How to Choose the Right Water Content for Your Contact Lenses

Quick Answer

For most people, low to moderate water content (around 38-43%) offers the best balance of comfort and moisture retention, especially if you have dry eyes. High water content lenses (above 50%) feel soft initially but can dehydrate faster, leading to discomfort later. Choose based on your tear film, wearing duration, and environment.

When shopping for contact lenses, you'll see 'water content' listed as a percentage on every box. But what does it actually mean, and does it matter for your eyes? In simple terms, water content is the percentage of water in the lens material. It affects how soft the lens feels, how well it lets oxygen through, and how quickly it dries out during wear.

Many people assume higher water content is always better because it feels moister at first. But the reality is more nuanced. High water content lenses can actually draw moisture from your eyes over time, leading to dryness. Understanding how water content interacts with your tear film, wearing schedule, and environment helps you choose a lens that stays comfortable from morning to night.

What Does Water Content Mean in Contact Lenses?

Water content is the percentage of the lens that is water by weight. For example, a lens with 38% water content is 38% water and 62% polymer. This percentage affects several key properties: oxygen permeability, softness, and dehydration rate. Higher water content usually means higher oxygen permeability (Dk/t), which is good for corneal health, but it also means the lens is more fragile and more prone to drying out.

On the other hand, lower water content lenses are often made with materials that retain moisture better and are more durable. They may feel slightly less soft initially, but they hold their shape and moisture longer. There is no universal 'best' percentage; the right choice depends on your individual eyes and how you wear your lenses.

• Water content is listed as a percentage on the lens packaging.
• It influences oxygen flow, softness, and how quickly the lens dehydrates.
• Higher percentage does not automatically mean better comfort.

High vs. Low Water Content: Pros and Cons

High water content contacts (typically above 50%) are very soft and flexible, which can feel comfortable when you first put them in. They also allow more oxygen to reach your cornea, which is beneficial for extended wear. However, because they contain more water, they lose moisture faster, especially in dry environments or if you blink less often. This can lead to a dry, gritty feeling later in the day.

Low water content contacts (around 38-43%) are firmer and more resistant to dehydration. They are often recommended for people with dry eyes because they don't pull as much moisture from the eye. They also tend to be more durable and easier to handle. The trade-off is slightly lower oxygen permeability, but for daily wear, this is rarely an issue. Many daily disposables fall in this range, making them a practical choice.

• High water content: very soft, high oxygen, but can dry out quickly.
• Low water content: retains moisture longer, more durable, but less soft.
• Consider your environment: air-conditioned offices or windy outdoors can increase dryness.

How Water Content Affects Comfort and Eye Health

The lens's water content interacts with your natural tear film. If you have healthy, abundant tears, a high water content lens may work fine. But if you suffer from dry eyes, a high water content lens can exacerbate the problem because it may absorb your tears to maintain its own moisture. In contrast, a lower water content lens is more stable and less likely to draw moisture from your eyes.

Additionally, water content affects how the lens feels on your eye. A lens with too little water might feel stiff, while one with too much can feel heavy or cause blurry vision as it dehydrates. The key is to find a balance that keeps your eyes hydrated without causing irritation. Pay attention to how your eyes feel at the end of the day—if they feel dry, you might need a lower water content lens.

• Dry eye sufferers often do better with lower water content lenses.
• High water content lenses can cause blurriness when they dry out.
• Regular blinking helps keep any lens hydrated.

Decision Rules for Choosing Water Content

• If you have dry eyes or work in dry environments: Choose lenses with lower water content (around 38-43%). They won't steal moisture from your eyes and tend to stay comfortable longer. Look for lenses with water content below 45%.
• If you have normal to oily eyes and prioritize oxygen: Higher water content (above 50%) can be comfortable and allow more oxygen. Just be prepared to use rewetting drops if they dry out. Consider high water content lenses but monitor comfort.
• If you are new to contacts or wear them occasionally: Daily disposables with moderate water content (around 43%) are a safe starting point. They offer a good balance and no cleaning hassle. Try a daily disposable with moderate water content first.

Water Content in Our Lenses

• A872 Blue: Water Content: 38% Material: HEMA With 38% water content, this monthly lens is on the lower end, making it a good option for those prone to dryness. The HEMA material is a standard hydrogel that retains moisture well.
• DooNoon Jinju Shell Olive: Water Content: 43% Material: Silicone Hydrogel At 43% water content, this daily disposable offers a middle ground. The silicone hydrogel material provides high oxygen permeability, and the moderate water content helps balance comfort and moisture retention.

Who Should Choose Which Water Content?

Best for Low Water Content (38-43%)

• People with dry eyes or who spend long hours in air-conditioned rooms
• Those who wear contacts for extended periods and need consistent moisture

Not Ideal for High Water Content (Above 50%)

• If you need very high oxygen permeability for extended wear, but be aware of dehydration risk
• If you are in a very humid environment, high water content may feel fine but can still dry out

Choosing the right water content is about matching the lens to your eye's natural moisture and your daily environment. Low to moderate water content is a safe bet for most, especially if you've experienced dryness. Always consult your eye care professional, and remember to follow the recommended replacement schedule for the healthiest experience.