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1.74 Ultra High-Index Lenses
The thinnest prescription lens material available. 1.74 index — up to 50% thinner than CR-39. For the strongest prescriptions where any other index would produce unacceptably thick lenses.
Starting from$99
1.74 Ultra High-Index Overview
1.74 index lenses represent the current pinnacle of thin-lens technology. They are the thinnest and lightest prescription lenses available, capable of handling even the strongest prescriptions with a cosmetically slim profile.
Who Needs 1.74?
1.74 high-index lenses are typically recommended for prescriptions above ±8.00 sphere, or for patients with ±6.00 and above who are particularly sensitive to lens thickness or who want the absolute slimmest lens possible.
Thickness Comparison
For a -10.00 sphere prescription:
- CR-39 (1.50): Edge thickness ~20mm — essentially unwearable
- 1.67 high-index: Edge thickness ~11mm
- 1.74 high-index: Edge thickness ~9mm — most cosmetically acceptable at this power
Considerations
- 1.74 lenses have higher chromatic aberration than lower-index materials — this may be noticeable in large frames
- Round frames minimize edge thickness for high prescriptions
- Anti-reflective coating is strongly recommended due to the higher reflectivity of 1.74 material
Common Questions
How do I know which lens index I need?
As a general guide: up to ±2.50 — CR-39 works fine. ±2.50–±4.00 — consider 1.60. ±4.00–±6.00 — 1.67 recommended. Above ±6.00 — 1.74 is ideal.
Does higher index mean better optical quality?
Not necessarily. CR-39 has the lowest chromatic aberration of all plastic materials. Higher index materials have slightly higher chromatic aberration, though most wearers don't notice it.
Are high-index lenses more fragile?
High-index lenses have higher clarity but are slightly more brittle than polycarbonate. For impact-prone situations (sports, children), polycarbonate's toughness outweighs the thinness benefit.
Get 1.74 Ultra High-Index Lenses
Order through LensesRx.com — choose the option that fits your situation.