Guide for First-Time
Simple power conversion
optical frame glasses power | ＜-4.00D | -4.00D~-5.25D | -5.50D~-7.00D | -7.25D~-8.25D | ≥-8.50D |
contact lens power | No need conversion | Minus 0.25D | Minus 0.50D | Minus 0.75D | Pls refer to professional. |
Note：The above conversion table is only for reference. If special circumstances such as high power and astigmatism, etc., pls consult physician or optometrist while purchasing.
Why contact lens power differs from glass power?
The power of contact lenses often differs from that of optical frame glasses due to their positioning relative to the eye. Glasses are worn a certain distance away from the eyes, whereas contact lenses sit directly on the tear layer covering the cornea. Practically eliminating the vertex distance effect. In optical principles, this means that for nearsighted individuals, the power of contact lenses is typically lower than that of glasses. For prescriptions up to -4.00D, this difference is usually negligible and doesn’t require conversion. However, for powers beyond -4.00D, specific adjustments are necessary. Optometrists take these factors into account during eye exams and select the most suitable lens power for each individual’s needs.
Strategy for First-Time Contact Lens Wearers
Time table for Initial Contact Lens Adaptation
For the first-time contact lens wearers, it is important to gradually increase wearing time step by step. This approach helps the cornea adjust to the mechanical irritation caused by the lenses and adapts to the lower-oxygen metabolic environment beneath the lens. It is advisable not to wear the lenses for an entire day initially.
Day | 1st day | 2nd day | 3rd day | 4th day | 5th day |
Wear Hour | 4 hours | 6 hours | 8 hours | 10 hours | 12 hours |
Periodic Review for Contact Lens Wearers:
It’s essential for individuals who wear contact lenses to have periodic review. This is a crucial aspect of contact lens maintenance and is key to successful long-term use. First-time wearers should undergo reviews after one week, one month, three months, six months, and on year of wear. If there is any discomfort or doubt about the lenses, it is important to consult a practitioner or ophthalmologist promptly for a thorough examination. Even experienced wearers should ensure to have a review at least once every six months.
Potential Symptoms and Solutions for First-Time Wearers:
1.Slight Foreign Body Sensation: this is usually not painful and lacks other abnormal signs. It may be due to the wearer adjusting to the lens edge or wearing the lens upside down.
2.Slight Dry Eyes: this can occur due to the lens affecting the eye’s tear film. Gradually increasing daily wear time can help.
3.Slight Hyperaemia (Redness) of the Eyes: this is often a normal initial reaction to contact lenses and should resolve within a few days, when there are no other discomforts.
4.Occasional Blurred Vision: New wearers may blink less, leading to tear film instability and fluctuating vision. This is generally normal. Maintaining regular blinking can help stabilize vision, which usually improves with short-term adaptation.
5.New vision difficulties: the accommodation force differs between contact lenses and traditional glasses, with contact lenses typically requiring greater accommodation. Minor near vision difficulties can usually be adapted to. However, if adaptation is challenging, switching to a lens with lower power may be necessary, in cases of severe symptoms or if symptoms persist without improvement, discontinue use immediately and consult the lens provider for a thorough evaluation.
Guide for First-Time
Wearing & Care Guide