NeuroCalm FLX+: Patented Dual-Band Spectral Filtering Technology

Verified patent identity

The patent was granted after examination for novelty and inventive step against two prior-art documents, a written reply and a formal hearing. The claims were amended twice before grant. A granted patent protects an invention; it is not a certification of safety, clinical benefit or regulatory clearance, and it confers no rights outside India.

Sources: [1], [2], [3], [4]

What the granted claim recites

Coatings, prescription or clip-on formats and any specific substrate beyond the worked example are described in the specification but are not part of the granted claims.

• A polymer ophthalmic lens (CR-39 is the worked example) with a functional smoke grey tint.
• Attenuation of 83 ± 2 percent across 460 to 490 nm and 78 ± 2 percent across 585 to 600 nm.
• A transmission peak of 23 to 25 percent in a 520 to 560 nm green comfort band, preserved relative to the two attenuated bands.
• Dye infused through the lens body in a surface-to-core concentration gradient with a 0.11 to 0.17 mm transition zone, chemically anchored by a 1.2 percent hexamethylene diisocyanate crosslinker (claims 1 and 4), rather than applied as a surface coating.
• At least 99 percent blocking of ultraviolet radiation below 400 nm (claim 3).
• A manufacturing method (claims 6 to 10): plasma-activated blanks, temperature-ramped ultrasonic-assisted dye infusion, two-stage thermal cure, real-time monitoring including optical coherence tomography, and spectrophotometric quality control to plus or minus 2 percent.

Sources: [1]

Engineering rationale, in two separate columns

The patent itself frames the two attenuated bands as the blue emission peak and the orange-red phosphor emission peak of LED, fluorescent and display lighting, with the green band kept for colour balance under artificial light. That is an optical-engineering rationale.

Separately, the company's technical note associates the 460 to 490 nm band with the melanopsin-driven ipRGC pathway and the 585 to 600 nm band with cone-driven pathways, drawing on published photophobia research. That is a design rationale informed by neuroscience; it is not evidence that the lens changes any biological response. Published work on 480 nm notch filters, where the one randomized trial found no advantage over a 620 nm comparator, illustrates why rationale and outcome must be kept apart.

Sources: [1], [6], [9], [10]

Spectral transmission characteristics

The granted specification reports band-averaged figures from the patentee's own measurements: about 1 percent transmission below 400 nm, about 6 to 7 percent at 400 to 450 nm, about 17 percent at 460 to 490 nm, a 23 to 25 percent peak at 520 to 560 nm, about 22 percent at 585 to 600 nm, rising to roughly 47 percent in the red. The specification also reports ten consecutive production batches within 81.9 to 84.0 percent and 76.9 to 79.0 percent attenuation in the two bands and spectral drift under 0.5 percent after accelerated ageing tests.

In the reply to the First Examination Report the patentee filed an EN ISO 12312-1 test table giving a luminous transmittance of 21.72 percent, filter category 2, with daytime road use passed and twilight or night driving marked not suitable; the laboratory is not named. The chart on this site is an illustration shaped to these band averages, labelled as such. No independent spectrophotometer trace has been published; the measured-data interface on the spectral transmittance page describes what a verified report would contain.

Sources: [1], [5], [8], [7]

Optical construction

The distinguishing construction feature is that the colour is in the lens material, not on it. Dye molecules are infused into the polymer under controlled temperature and ultrasonic agitation, forming a gradient from surface to core, and are then chemically crosslinked so that the spectral profile is fixed in the body of the lens. Surface coatings such as anti-reflection or hard coats are optional, conventional and not covered by the patent. Because the tint is in the material, it is independent of coating wear; the specification's ageing data are the patentee's accelerated tests, not field data.

Sources: [1]

Appropriate use and limitations

• A category 2 tint with about 21 to 25 percent visible transmission is a daytime lens. It is not suitable for driving in twilight or at night.
• It is a general-purpose optical filter, not a medical device, and it has not been evaluated by any medical-device regulator.
• No clinical outcome study of NeuroCalm FLX+ has been published. Published trials of rose, FL-41 and notch-filter lenses concern other products and populations and do not transfer.
• The patent protects the invention in India only. It is not an international patent and it is not a certification of performance.
• Dispensing follows an in-person assessment by an eye-care professional, who should consider the wearer's diagnosis, prescription, lighting environment and driving needs.

Sources: [5], [7], [1], [9]

Professional evaluation and clinical access

NeuroCalm FLX+ is provided through participating eye-care professionals after an assessment. The clinicians page explains what professional information is available and how to request technical documentation; the locations page lists participating practices once each has been verified, and is empty until then. Enquiries go to the company's verified mailbox; no personal health details are needed to ask a question.

Evidence: established versus emerging

Established

• The patent identity, dates, parties, claim wording and figures above are taken from official Patent Office documents.
• A lens is a passive filter: the figures describe light, not biology.

Emerging or unresolved

• The neuroscience rationale for the band choice is the company's design reasoning, informed by published research on other filters and on photophobia mechanisms.

Questions and evidence-based answers

Continue reading

• Spectral transmittance and how filters are measured
• Glasses for photophobia and light sensitivity
• Melanopsin, ipRGCs and neural responses to light
• For clinicians: professional information
• Participating locations

References

1. Published granted specification IN587746 B1: An optical lens with dual-band selective light attenuation (10 claims). Intellectual Property Office, India, 2026.
2. Certificate of Grant of Patent, Patent No. 587746 (SL No 022155886). Intellectual Property Office, India, 2026.
3. Intimation of grant of patent under section 43, application 202521094370. Intellectual Property Office, India, 2026.
4. First Examination Report, application 202521094370. Intellectual Property Office, India, 2025.
5. Reply to the First Examination Report with EN ISO 12312-1 test table. Sleepaxa Private Limited (applicant submission through its patent agent), 2025.
6. Dubey S, Choudhary M. Dual-Band Selective Light Attenuation: Engineering Principles Behind NeuroCalm FLX+ Patented Technology. Zenodo technical note (Sleepaxa Private Limited), CC BY 4.0, 2026. DOI 10.5281/zenodo.19547790.
7. ISO 12312-1, Eye and face protection, Sunglasses and related eyewear, Part 1: Sunglasses for general use (filter categories 0 to 4 by luminous transmittance; driving suitability). International Organization for Standardization. (Cited by designation; licensed text not opened.)
8. ISO 8980-3, Ophthalmic optics, Uncut finished spectacle lenses, Part 3: Transmittance specifications and test methods. International Organization for Standardization. (Cited by designation; licensed text not opened.)
9. Hoggan RN, Subhash A, Blair S, et al.. Thin-film optical notch filter spectacle coatings for the treatment of migraine and photophobia. Journal of Clinical Neuroscience, 2016. PMID 26935748. DOI 10.1016/j.jocn.2015.09.024.
10. Noseda R, Kainz V, Jakubowski M, et al.. A neural mechanism for exacerbation of headache by light. Nature Neuroscience, 2010. PMID 20062053.
11. Katz BJ, Digre KB. Diagnosis, pathophysiology, and treatment of photophobia. Survey of Ophthalmology, 2016. PMID 26875996. DOI 10.1016/j.survophthal.2016.02.001.