GB-37 (Guang Ming) Bright Light

What does GB-37 Guang Ming do?

Guang Ming GB-37 is the Luo (Connecting) point of the Gall Bladder channel of Foot Shao Yang, and it is the channel's distal eye point — the point on the lower leg that the tradition reaches for when the complaint is in the eye. Sacred Lotus sources & references carry the Connecting classification directly, and the two facts are linked: a Connecting point sends a branch to its paired channel, and the Gall Bladder's pair is the Liver, the organ said to open into the eyes. GB-37 is where a Gall Bladder point acquires a Liver action, and the eye is what it acquires it for.

• Benefits the eyes — the primary recorded action and the one the name announces. It is applied to blurred vision, eye pain, night blindness and dryness, and it is the standard distal choice, used at a distance from the eye rather than beside it.
• Connects with the Liver channel — the Luo action. The Connecting vessel of the Gall Bladder channel runs to the Liver channel, which is the theoretical route by which a point five cun above the ankle is credited with an effect on vision.
• Dispels wind-damp, activates the channel and alleviates pain — the channel action along the lateral lower leg, applied to knee pain, weakness and heaviness of the legs and pain along the outer aspect of the limb.
• Benefits the breasts — Sacred Lotus sources & references record distending pain of the breast among its indications and stopping lactation among its uses. Both belong to the Liver-and-Gall-Bladder territory the Connecting vessel reaches, since the Liver channel is the one associated with the breast and the chest sides.
• Regulates Liver qi — the action behind its use where eye symptoms, flank distension and irritability are read as one constrained pattern rather than three complaints.

Source: Sacred Lotus sources & references (channel and Luo classification, existing action, indication and use records); Deadman & Al-Khafaji, A Manual of Acupuncture (p. 454); Chinese Acupuncture & Moxibustion (p. 219); cross-referenced against multiple online sources.

What is GB-37 Guang Ming used for?

GB-37 is used above all for disorders of the eye and of vision, and secondarily for pain and weakness along the outer lower leg and for distending pain of the breast. The indications below are those carried in Sacred Lotus sources & references and set out in the standard reference literature. They describe traditional use, not proven treatment.

• Blurring of vision
• Ophthalmalgia — pain in the eye
• Night blindness
• Dryness and itching of the eyes
• Redness and swelling of the eyes
• Excessive watering of the eyes
• Pain in the knee
• Muscular atrophy of the lower limb
• Motor impairment of the lower extremities
• Pain of the lower extremities along the Gall Bladder channel
• Distending pain of the breast
• Headache and dizziness attributed to the Gall Bladder channel

The eye indications and the leg indications arrive by different routes and it is worth keeping them apart. The eye indications belong to the Connecting classification and the link to the Liver channel; the leg indications belong to the point's ordinary position on the lateral lower leg, where any Gall Bladder point in that segment would carry them. The breast indication belongs with the eye group, by way of the Liver.

Source: Sacred Lotus sources & references (existing indication and use records); Deadman & Al-Khafaji, A Manual of Acupuncture (p. 454); Chinese Acupuncture & Moxibustion (p. 219); cross-referenced against multiple online sources.

Where is GB-37 Guang Ming, and how is it used in practice?

Guang Ming lies on the outer side of the lower leg, five cun above the tip of the outer ankle bone, at the front edge of the fibula — the slender outer bone of the calf. Five cun above the ankle prominence is a little above the lower quarter of the lower leg; the front border of the fibula can be traced with a fingertip, and the point sits along it. Sacred Lotus sources & references also record one practical use in a single line — it stops lactation — which is worth knowing because it is not obvious from the name and because it is the same Liver-channel connection that gives the point its eye action, seen from a different side.

Which points is GB-37 combined with?

• With Tai Chong LIV-03 — the essential pairing. This is the Yuan-Luo combination: the Connecting point of one channel with the Source point of its interior-exterior partner. GB-37 is the Gall Bladder's Connecting point and LIV-03 the Liver's Source point, so the pair works the Liver-and-Gall-Bladder relationship in exactly the way the classification intends. For eye complaints read as belonging to the Liver, it is the standard distal prescription.
• With Jing Ming BL-01 and Zan Zhu BL-02 — the local eye points at the inner corner of the eye and the inner end of the eyebrow, with GB-37 as the distal point. Local-plus-distal along the relevant channels is the classical structure for eye disorders, and this is its commonest form.
• With Tong Zi Liao GB-01 and Tai Yang — the local points at the outer corner of the eye and the temple, both on or beside the Gall Bladder channel's beginning, again with GB-37 distally.
• With Feng Chi GB-20 — the Gall Bladder point at the back of the head that is itself credited with benefiting the eyes; GB-20 and GB-37 are the channel's two principal non-local eye points, one at each end of it.
• With Di Wu Hui GB-42 — the next Gall Bladder point with an eye association further down on the foot. The pair of GB-37 and GB-42 alone, with no local points at all, is the prescription used in the dry-eye trial described under research.
• With Yang Ling Quan GB-34 and Xuan Zhong GB-39 — the channel's other lower-leg points, added when the leg rather than the eye is the target: GB-39 sits three cun above the ankle on the same aspect, GB-37 five cun.
• Method — Sacred Lotus sources & references record moxibustion as applicable at this point.

Which eye points does this site hold, and where does GB-37 fit among them?

Eye complaints are treated with a small, well-defined group of points, and Sacred Lotus sources & references hold the whole of it. Seeing them together shows what GB-37 is for, because it is the odd one out:

• Around the eye (local). Jing Ming BL-01, "Bright Eyes", at the inner corner — a meeting point of five channels and three vessels, and the most local of them all. Zan Zhu BL-02 at the inner end of the eyebrow. Yu Yao, the extra point in the middle of the eyebrow above the pupil. Si Zhu Kong SJ-23 at the outer end of the eyebrow. Tong Zi Liao GB-01 at the outer corner. Qiu Hou, the extra point beneath the eyeball itself at the outer quarter of the lower orbital rim. Tai Yang, the extra point at the temple.
• On the head, at a short distance. Tou Lin Qi GB-15 above the pupil at the hairline, Mu Chuang GB-16 — "Eye Window" — behind it, and Feng Chi GB-20 at the base of the skull.
• Distal — on the limbs. Tai Chong LIV-03 on the foot, by way of the Liver's association with the eyes, and Guang Ming GB-37 on the lower leg, which is the one named for the function. Di Wu Hui GB-42 on the foot carries a lesser eye association.

GB-37's place in that group is specific: it is the point used when the practitioner wants to act on the eye without needling next to it — in an inflamed or painful eye, in a patient who cannot tolerate periorbital needling, or as the distal half of a local-and-distal prescription. That is also the arrangement the published trial evidence has tested most directly, and the results are set out under research.

Source: Sacred Lotus sources & references (location, Luo classification, existing use record, and the BL-01, BL-02, GB-01, GB-15, GB-16, GB-20, GB-42, SJ-23, LIV-03, Tai Yang, Qiu Hou and Yu Yao point records queried directly); Deadman & Al-Khafaji, A Manual of Acupuncture (p. 454); Chinese Acupuncture & Moxibustion (p. 219); cross-referenced against multiple online sources.

Where is GB-37 located?

• A Manual of Acupuncture (p. 454): On the lateral aspect of the lower leg, 5 cun superior to the prominence of the lateral malleolus, at the anterior border of the fibula.
• Chinese Acupuncture and Moxibustion (p. 219): 5 cun directly above the tip of the external malleolus, on the anterior border of the fibula.

How is GB-37 Guang Ming needled in the textbooks?

Reference record only — this describes what the standard texts document, not instruction for a reader. GB-37 is among the lower-hazard points on the body: it lies on the outer lower leg, over muscle and bone, with no body cavity and no major organ beneath it. Sacred Lotus sources & references record perpendicular insertion of 0.7 to 1.0 inch, with moxibustion applicable. Needling is carried out only by a qualified, licensed practitioner.

• Angle and depth documented. Perpendicular, 0.7 to 1.0 inch in the record held here. Chinese Acupuncture & Moxibustion (p. 219) and Deadman & Al-Khafaji (p. 454) record insertion in a comparable range at this point; Deadman & Al-Khafaji additionally describe an oblique direction along the channel for particular applications.
• What lies beneath. Skin and subcutaneous tissue, then the muscles of the outer compartment of the leg — the long and short fibular (peroneal) muscles — lying against the front border of the fibula, which is the point's own landmark. The superficial fibular nerve descends through this compartment and becomes superficial in the lower third of the leg, and the anterior tibial vessels lie deeper and more medially in the compartment in front. These are the ordinary anatomical relations of a lateral lower-leg point; the fibula itself bounds the depth.
• The common consequence of contact with small vessels is bruising. Bleeding and bruising at the needle site are the most frequently recorded acupuncture adverse events of any kind: a meta-analysis of prospective clinical studies found that roughly half of all recorded events were bleeding, pain or flare at the site, and estimated serious adverse events at approximately 1 per 10,000 patients and around 8 per million treatments (Bäumler P et al., BMJ Open 2021;11:e045961, PMID 34489268).
• Moxibustion — recorded as applicable.
• One traditional-use consideration worth recording. Sacred Lotus sources & references list stopping lactation among this point's uses. That recorded action is the reason the point appears in the reference literature in connection with breastfeeding — the same fact seen from the other side. It is set down here as reference information about what the sources record, not as advice.
• No single agreed safe depth exists for any acupuncture point. Two systematic reviews of the safe-depth literature — 33 studies in the first, 47 in the second — both concluded that depths measured for the same point vary greatly with the subject group and the measuring method, and that the definition of "safe depth" has never been standardised (J Altern Complement Med 2011;17(3):199–206, PMID 21417806; Evid Based Complement Alternat Med 2013;2013:740508, PMID 23935678). At a lower-leg point the practical consequence is small; the principle holds across the whole set of records.

A point about the eye that belongs here. GB-37 is a leg point used to treat the eye, and that is precisely why it carries a lower risk profile than the local eye points do. Needling beside or behind the eyeball is the genuinely hazardous end of ophthalmic acupuncture — inadvertent ocular perforation from traditional acupuncture has been reported in the ophthalmic literature (JAMA Ophthalmol 2022;140(6):e221452, PMID 35708617) — and the records held here for the periorbital points reflect that. Nothing of the kind applies at GB-37. It is worth stating plainly, because it is one of the practical reasons a distal eye point exists at all.

Source: Sacred Lotus sources & references (existing needling and use records); Deadman & Al-Khafaji, A Manual of Acupuncture (p. 454); Chinese Acupuncture & Moxibustion (p. 219); PubMed PMID 34489268; PMID 21417806; PMID 23935678; PMID 35708617 — each verified resolvable and checked for retraction status before citation.

What does the name Guang Ming mean?

Guang Ming means "Bright Light" — guang, light or brightness, and ming, bright or clear. Sacred Lotus sources & references translate it exactly so. The name is a statement of function: this is the point on the leg credited with brightening the eyes, and the doubling of two characters both meaning brightness is emphatic rather than descriptive of any anatomical feature. It is one of the small number of acupuncture point names that tells a reader what the point is for and nothing else — no landmark, no metaphor of terrain, no reference to a vessel. Compare the names of the points it works with: Jing Ming BL-01 is "Bright Eyes", and Mu Chuang GB-16 is "Eye Window". The eye repertoire is unusually plain-spoken in its naming.

Why does the Luo (Connecting) point classification matter at GB-37?

Each of the twelve regular channels has a Connecting point from which a branching vessel — the luo mai — runs across to its interior-exterior partner channel. That is the mechanism by which a point on one channel is credited with acting on the other's organ, and at GB-37 it is the whole explanation for the point's reputation: the Gall Bladder's Connecting vessel runs to the Liver, and the Liver in classical theory opens into the eyes and stores the blood that is said to nourish them. A point five cun above the outer ankle has no local relationship with vision whatsoever. The Connecting classification is what supplies one.

The standard way of using a Connecting point is the Yuan-Luo combination — the Connecting point of the affected channel with the Source point of its partner. For GB-37 the partner is Tai Chong LIV-03, the Liver's Source point; conversely LIV-05 Li Gou, the Liver's Connecting point, pairs with GB-40 Qiu Xu, the Gall Bladder's Source point. Reading those two pairs side by side is the clearest way to see the structure.

Sacred Lotus sources & references hold the complete set of fifteen Connecting points: the twelve channel Luo points — LU-07 Lie Que, LI-06 Pian Li, ST-40 Feng Long, SP-04 Gong Sun, HT-05 Tong Li, SI-07 Zhi Zheng, BL-58 Fei Yang, KI-04 Da Zhong, P-06 Nei Guan, SJ-05 Wai Guan, GB-37 Guang Ming and LIV-05 Li Gou — together with REN-15 Jiu Wei, the Connecting point of the Conception Vessel, DU-01 Chang Qiang, the Connecting point of the Governing Vessel, and SP-21 Da Bao, the Great Connecting point of the Spleen. Four of the twelve — LU-07, P-06, SJ-05 and SP-04 — also carry a Confluent-point classification for an extraordinary vessel. GB-37 does not; it is a Connecting point and nothing else, which makes it one of the cleaner illustrations of what the classification does on its own.

Is there research on GB-37 Guang Ming?

Yes — and GB-37 is one of the better-studied individual points in the repertoire, with published work in which it is the only point tested or one of only two. That is rare, and it makes the evidence here worth more than the multi-point protocol evidence that dominates acupuncture research.

• Needling GB-37 alone in myopia, with EEG. Twenty-two people with myopia had uncorrected distance visual acuity and contrast sensitivity measured before and after acupuncture at GB-37 only, with electroencephalography recorded throughout. Both acuity and contrast sensitivity improved at each spatial frequency tested, and the EEG "microstate" analysis showed increased duration, occurrence and contribution of microstate A and a decrease in microstate D, with microstate A duration positively correlated with contrast sensitivity (Wang Z et al., Front Neurosci 2024;18:1492529, PMID 39640293, PMC11618237). This is a single-arm study in twenty-two people with no control group and short-term outcomes — it cannot show that the effect is specific to this point or that it lasts. But it tests this point on its own, which almost no acupuncture study does.
• Distal points versus local points in dry eye — a direct test of what GB-37 is for. Forty patients with xerophthalmia were randomised to a distal group needled at GB-37 and Di Wu Hui GB-42 only, or to a local group needled at Zan Zhu BL-02, Tong Zi Liao GB-01 and Tai Yang, once daily, five days a week for two weeks. Both groups improved on symptom scores, tear secretion, ocular surface disease index and tear break-up time. At the two-week follow-up the differences in tear secretion and break-up time favoured the distal group significantly, while the subjective scores did not differ (Wang C et al., Zhongguo Zhen Jiu 2017;37(10):1069–72, PMID 29354975). Forty patients is small and there was no sham arm, but the comparison is exactly the one this point's classification predicts.
• Point specificity, measured with thermal imaging. Patients with peripheral facial paralysis were divided into a GB-37 group and a He Gu LI-04 group and needled accordingly, with facial temperature mapped by infrared thermography before and after. After needling GB-37, temperature rose in the areas around the eyes on both sides and most on the affected side, significantly more than in other facial areas; after needling LI-04, the rise was around the mouth. The authors read this as objective evidence of point specificity — each distal point mapping to the facial region its channel theory assigns it (Song XJ, Zhang D, Zhongguo Zhen Jiu 2010;30(1):51–4, PMID 20353116). Small, unblinded and physiological rather than clinical, but the eye result is specific to this point.
• GB-37 within eye-disease protocols. The point recurs in trials of acupuncture for childhood amblyopia and myopia as a component of a prescription — for example a functional MRI study of children with anisometropic amblyopia in which GB-37 was needled alongside BL-01 Jing Ming, BL-02 Zan Zhu and GB-20 Feng Chi (Int J Ophthalmol 2024, PMID 38371252), and a randomised trial of acupuncture for vision and visual function in children with anisometropic amblyopia (Zhongguo Zhen Jiu 2024;44(2), PMID 38373760). These are protocol-level results and say nothing about GB-37 individually; they are listed to show where the point sits in current practice, not as evidence for it.

Is the eye indication for GB-37 as old as it looks?

This is the most interesting thing in the literature about this point, and it deserves to be stated openly rather than smoothed over. A historical study of the acupuncture classics argues that GB-37's eye indication is not continuous from antiquity. The name Guang Ming predates the Huang Di Ming Tang Jing, the earliest surviving work on point locations — but the study finds that in works before the Song dynasty the point was not used for eye disease. In Dou Hanqing's Song-dynasty Zhen Jiu Biao You Fu, "Guangming" is used to treat eye disorders as an alias for Zan Zhu BL-02, the point at the inner end of the eyebrow. The study's argument is that the Yuan-dynasty Bian Que Shen Ying Zhen Jiu Yu Long Jing mistook that alias for Guang Ming GB-37 on the Gall Bladder channel and added eye itch to GB-37's indications, after which later works repeated it and modern scholarship inherited it — and then confirmed an effect experimentally (Huang T, Wu MZ, Zhonghua Yi Shi Za Zhi 2016;46(3):161–4, PMID 27485868).

Two things follow, and both are worth holding at once. First, an indication's antiquity is not the same as its correctness, and a reader should not assume that "the classics say so" means an unbroken line back to the Han. Second, the modern point-specific work above — needling GB-37 alone and measuring vision, and mapping needling at GB-37 to a temperature change around the eyes — was carried out on this point, whatever the route by which the indication reached it. We record the scholarly account because it is published and because accuracy is the standard here; we do not treat it as settling the clinical question either way. It is one historian's reconstruction, and readers should know it exists.

How does GB-37 compare with the points around it?

Xuan Zhong GB-39 lies two cun lower, three cun above the outer ankle on the same aspect of the leg, and is the Hui-Meeting point of Marrow — a different classification and a different use, but close enough that the two are easily confused when counting up from the ankle. Yang Fu GB-38 sits between them at four cun as the channel's Jing-River and Fire point. Wai Qiu GB-36, seven cun up, is the channel's Xi-Cleft point. Yang Ling Quan GB-34, just below the knee, is the Hui-Meeting point of the Sinews and the channel's He-Sea point — the leg point of first resort for sinew problems, where GB-37 is the leg point of first resort for the eyes. On the other side of the relationship, Li Gou LIV-05 is the Liver's Connecting point and GB-37's exact structural mirror: each connects to the other's channel. And Tai Chong LIV-03 is GB-37's constant partner, both in the Yuan-Luo structure and in practice.

Source: Sacred Lotus sources & references (name, translation, Luo classification, the full fifteen-point Connecting set queried directly, and the GB-34, GB-36, GB-38, GB-39, GB-42, LIV-03 and LIV-05 point records); Deadman & Al-Khafaji, A Manual of Acupuncture (p. 454); Chinese Acupuncture & Moxibustion (p. 219); PubMed PMID 39640293 (PMC11618237); PMID 29354975; PMID 20353116; PMID 38371252; PMID 38373760; PMID 27485868 — each verified resolvable and checked for retraction status before citation; cross-referenced against multiple online sources.