Last Updated: May 27, 2026Reviewed by: Andrei Dokukin, MDTier C — Investigational / researchGRADE: Moderate

Off-label ophthalmology applicationsLimited RCT evidence

Ophthalmologic indications are off-label (Tier B / Tier C). See the Coverage Map for an organ-system view of evidence tiers, and How Evidence Is Graded for methodology.

Investigational / Research Priority

Ophthalmic applications of hirudotherapy are not included in FDA 510(k) clearance for medicinal leeches. No ophthalmic indication has received specific regulatory clearance in the United States, the European Union, or any other major jurisdiction.

Investigational Application

Ophthalmology is not included in the FDA 510(k) clearance for medicinal leeches. The information below summarizes international clinical experience and published research. ASH advocates for rigorous clinical evaluation of these applications.

International Clinical Evidence

The following evidence reflects international clinical experience. Practice standards, regulatory frameworks, and levels of evidence vary by jurisdiction. U.S. practitioners should refer to FDA guidance and applicable state regulations.

Ophthalmic hirudotherapy occupies a distinctive position within investigational leech medicine. The eye is an organ of exquisite vascular sensitivity: a rise of a few millimeters of mercury in intraocular pressure, a microvascular occlusion in a retinal arteriole, or a thrombus in the central retinal vein can destroy vision within hours. Published international clinical experience documents the largest cumulative dataset among investigational specialties — a substantial number of patients across glaucoma, retinal vascular disease, inflammatory eye conditions, and visual rehabilitation. The Moscow MNTC “Eye Microsurgery” treated more than 300 patients annually over 15+ years. No randomized controlled trial has been performed for any ophthalmic indication.

Biological Rationale

Glaucoma Mechanisms

Hirudin-mediated anticoagulation may reduce ciliary body secretion; hyaluronidase-facilitated tissue permeability may improve trabecular outflow; histamine-like vasodilation may enhance uveal blood flow. Controlled blood extraction reduces orbital venous pressure.

Retinal Vascular Pathways

Hirudin inhibits thrombin; destabilase-M lyses cross-linked fibrin; calin and saratin suppress platelet adhesion; lipase/cholesterol esterase fractions exert anti-atherosclerotic effects. Published research describes enhanced retinal perfusion and collateral development.

Anti-Inflammatory Cascade

Eglins block neutrophil elastase and cathepsin G; C1s complement inhibitor modulates classical pathway; hyaluronidase enhances lymphatic drainage; LDTI tryptase inhibitor attenuates mast cell-mediated inflammation in autoimmune ocular conditions.

The convergence of anticoagulant, fibrinolytic, anti-inflammatory, and vasoactive agents in a single biological secretion is particularly relevant to ophthalmology, where pathophysiologic mechanisms across glaucoma, retinal vascular disease, and inflammatory conditions overlap.

Clinical Evidence

GRADE Evidence Level: Low

Observational studies or RCTs with serious limitations

Published Clinical Evidence — All Ophthalmic Indications
Study	Design	Population (n=)	Intervention	Key Outcome	Result
Mozherenkov et al. 1998	Comparative cohort	Acute angle-closure glaucoma (n=302)	HT (2-3 leeches, temple) + standard tx vs standard tx alone	Attack resolution rate	87% with HT (n=177) vs 77% without (n=125); p < 0.05 Level III; strongest comparative data for any ophthalmic indication
Bondareva & Zhitenev 1998	Case series	Acute glaucoma — emergency protocol (n=500)	Leeches + acetazolamide + pilocarpine	Pain, congestion, corneal edema	Pain reduction/resolution at 30-40 min post-application Level IV; largest single ophthalmic HT cohort
Bagdasarova 1973	Prospective cohort — tonometric	Glaucoma (n=181)	Leech application; tonometry before and at 1, 3, 24 h after	Intraocular pressure	IOP already decreasing within 1 h; approached baseline levels by 24 h Level IV; consistent temporal pattern
Bagdasarova 1973	Prospective cohort — tonographic	Glaucoma — aqueous dynamics (n=159)	Leech application; tonographic measurement	True IOP, outflow facility, aqueous secretion	All three significantly improved; outflow facility markedly increased Level IV; mechanism data — genuine outflow improvement, not transient volume change
Semikova & Bondareva 1995	Prospective case series	Keratitis, iridocyclitis, uveitis — MNTC program (n=300)	Periorbital application; 6-10 sessions q2-3 days	Infiltrate, tenderness, synechiae, mydriatic response	Corneal clearing; synechiae lysis; enhanced mydriatic effect Level IV
Semikova et al. 1999	Program-volume note (not a discrete cohort study)	MNTC "Eye Microsurgery" postoperative patients, various pathologies (n=300)	Ongoing HT program, >15 years	Annual program volume	>300 patients/year receive HT courses at the MNTC; a single session is described nearby as often sufficient for postoperative iritis/iridocyclitis/macular edema/IOP rise Level IV; annual MNTC volume
Bondareva 1998	Case series	Late period after acute circulatory disturbances of retinal/optic nerve vessels (n=12)	10 sessions; alternating temporal/mastoid; 2-4 leeches	Visual acuity, visual field	VA: 0.01→0.1, 0.1→0.5-0.6, 0.08→0.3, 0.8→1.0; VF +10-20° Level IV; subjective improvement in all 12 patients
Mukhanko & Kulanin 2001	Comparative cohort	Blind/visually impaired — rehabilitation (n=NR)	HT + resort factors and physiotherapy vs the same without HT	Visual function improvement	Positive dynamics of visual function in 69% with HT vs 50% without HT Level III; combined intervention limits attribution
Vedeneeva & Medvedeva 2000	Case report	Thyroid ophthalmopathy (n=1)	HT for orbital edema, proptosis, diplopia	Clinical response	Successful treatment Level V
Yoyleva et al. 1999	Case series	Optic neuropathies (n=NR)	HT + magnetostimulation	Visual function	Enhanced efficacy with combination therapy Level IV; n not reported

Glaucoma: Strongest Comparative Data

Mozherenkov et al. (1998) provided the closest approximation to comparative data: in 302 patients with acute angle-closure glaucoma, the hirudotherapy group achieved 87% attack resolution versus 77% with standard treatment alone (p<0.05). Bondareva and Zhitenev (1998) documented 500 patients receiving leeches alongside acetazolamide and pilocarpine, with pain reduction at 30-40 minutes post-application.

Bagdasarova (1973) conducted tonographic analysis in 159 patients. True IOP decreased, outflow facility increased markedly, and aqueous humor secretion showed compensatory increase — a homeostatic response to improved outflow, not a pathologic rise. These data provide a physiologic explanation for clinical IOP reductions and suggest genuine improvement in outflow physiology rather than transient blood volume reduction.

Physiologic Mechanism Evidence

The Bagdasarova tonographic data are noteworthy: they demonstrate a specific mechanism (improved outflow facility) rather than documenting only clinical endpoints. The compensatory secretion increase is consistent with restored outflow capacity.

Retinal Vascular Disease: Visual Acuity Outcomes

Bondareva (1998) treated 12 patients in the late period after acute circulatory disturbances of the retinal and optic nerve vessels (10 sessions, alternating temporal/mastoid). Visual acuity gains were clinically significant: 0.01 to 0.1 (n=2), 0.1 to 0.5-0.6 (n=5), 0.08 to 0.3 (n=3), 0.8 to 1.0 (n=1), with visual field expansion of 10-20 degrees. Subjective improvement was reported in all 12 patients.

Inflammatory Eye Disease: MNTC Program

Keratitis & Iridocyclitis

Published research documents decreased corneal infiltrate and progressive clearing. Enhanced mydriatic drug action was reported — suggesting SGS-mediated improvement in microcirculatory drug penetration. Posterior synechiae breakdown with pupil dilation documented in iridocyclitis cases.

Uveitis & Postoperative

Combined therapy produced reduced vitreous precipitates and prevention of coarse vitreous strands. Post-intraocular surgery complications (iritis, macular edema, elevated IOP) managed with single session in many cases, reducing need for additional intervention.

Additional Indications

Radiation Complications

Semikova (1998) described leech application for radiation-induced inflammation following uveal melanoma treatment. Ocular hemorrhage (hemophthalmos) documented as responsive to SGS fibrinolytic activity.

Optic Neuropathy

Retrobulbar neuritis and papilledema responded in acute stage. Yoyleva et al. (1999) reported enhanced efficacy when combined with magnetostimulation. Sympathetic ophthalmia particularly emphasized.

Rehabilitation

Positive dynamics of visual function in 69% of patients with HT vs 50% without (Mukhanko & Kulanin 2001); in a later series, improvement (n=448) or stabilization (n=92) with no deterioration (Mukhanko & Kulanin 2003).

Clinical Protocol — Periorbital Application

Standard Protocol

Preparation: Clean temple/mastoid; no residual antiseptic
Method: 2 leeches in glass vial pressed against temple or mastoid
Duration: Until engorgement and spontaneous detachment (20-40 min)
Course: 6-10 sessions at 2-3 day intervals
Bilateral: 2 leeches (unilateral) or 4 leeches (bilateral)

Acute Glaucoma Crisis

Leeches: 2-3 to temple; +1 mastoid in severe cases
Assessment: Re-evaluate at 30-40 min for pain/IOP response
Sessions: Single session may suffice
Integration: Adjunct to acetazolamide + pilocarpine only

Site Selection by Indication
Indication	Primary Site	Alternative	Leeches	Course
Inflammatory disease	Temple (ipsilateral)	Mastoid	2	6-10 sessions, q2-3d
Chronic glaucoma	Temple (ipsilateral)	Mastoid	2	6-10 sessions, q2-3d
Acute glaucoma	Temple (ipsilateral)	Mastoid (severe)	2-3 (+1)	Single; reassess 30-40 min
Retinal vascular	Temple (alternating)	Mastoid (alternating)	2 or 4	10 sessions
Postoperative	Temple (ipsilateral)	Mastoid	2	Single session often sufficient

Pre-Procedure Assessment

Complete ophthalmic exam: VA, IOP (Goldmann tonometry), slit-lamp, dilated fundus
Visual field testing (automated perimetry) for glaucoma/retinal vascular patients
CBC, coagulation panel, medication review (anticoagulants, antiplatelets)
Prior leech exposure and allergy history assessment
Counseling: periorbital ecchymosis, bleeding duration, cosmetic scarring

Post-Procedure Monitoring

Sterile dressing; expect 4 to 24 hours post-detachment oozing
IOP at 1, 3, and 24 hours (glaucoma patients per Bagdasarova protocol)
VA and visual field testing at course completion
Periorbital infection assessment at each session

Safety Considerations

Critical Safety Requirements

Globe proximity: Leeches must never be applied to eyelids or conjunctiva. The glass vial containment method is mandatory — prevents migration toward the eye throughout the entire application period.
Cavernous sinus pathway: The periorbital region drains into the cavernous sinus via valveless ophthalmic veins. Aeromonas hydrophila could theoretically propagate intracranially. No such case reported; prophylactic antibiotics (fluoroquinolone or TMP-SMX) should be considered in immunocompromised patients.
Anticoagulant interactions: Patients on warfarin, DOACs, heparin, aspirin, or clopidogrel may experience prolonged bleeding. Coagulation status must be assessed before treatment initiation.

Periorbital Ecchymosis

Post-detachment bleeding may produce “black eye.” Self-limiting, resolving within 7-10 days. Pre-treatment counseling required.

Infection Risk

Prophylactic antibiotics recommended for immunocompromised patients. Standard wound care. Heightened surveillance for cavernous sinus drainage pathway.

Cosmetic Scarring

Triradiate bite mark heals as small, pale scar. Usually inconspicuous on temple skin. Patients require informed consent regarding facial scarring.

Medication Interactions in Ophthalmic Hirudotherapy
Medication	Interaction	Action
Warfarin, DOACs, heparin	Additive anticoagulant effect; prolonged bleeding	Assess coagulation; coordinate with prescriber
Aspirin, clopidogrel	Additive antiplatelet via calin/saratin	Bleeding time assessment; ecchymosis counseling
Mydriatics (atropine, tropicamide)	Enhanced effect reported (improved drug penetration)	Monitor for excessive mydriasis
Acetazolamide (oral)	Additive IOP reduction via different mechanisms	Documented in acute glaucoma protocols
Prostaglandin analogs	No published data	Theoretical additive benefit; no safety data

Evidence Gaps and Research Priorities

Methodological Limitations

No RCTs for any ophthalmic indication
All evidence Level III-IV (comparative cohorts, case series)
Multiple combined-intervention studies limit attribution
Periorbital application inherently difficult to blind
Geographically homogeneous populations (Russian centers)
Non-standardized outcome measures across studies

Priority Research Areas

Pragmatic RCT: adjunctive HT in acute angle-closure glaucoma
Prospective registry with ETDRS VA, Goldmann IOP, automated VF
Dose-response: optimal leech count, frequency, course duration
SGS pharmacokinetics in periorbital tissues
Long-term follow-up: IOP durability, VA stability at 6-12 months
Infection surveillance: cavernous sinus pathway risk

ASH supports development of prospective registries with standardized endpoints. The consistent direction of benefit across multiple investigators and institutions over 15+ years provides a foundation for rigorous prospective studies. Acute angle-closure glaucoma (n=302, p<0.05) is the most promising candidate for a pragmatic RCT.

Key Takeaways

Largest investigational evidence base: Over 1,100 patients across glaucoma, retinal vascular, and inflammatory eye disease, with >300 patients/year treated at specialized centers for over 15 years.

Strongest comparative data: 87% vs 77% attack resolution in acute angle-closure glaucoma (p<0.05; Mozherenkov 1998, n=302) — adjunct to standard pharmacologic management.

Documented physiologic mechanism: Tonographic studies (n=159) demonstrate improved aqueous humor outflow facility — genuine physiologic improvement, not transient blood volume reduction.

Multi-target SGS pharmacology: Hirudin (anticoagulation), destabilase (fibrinolysis), hyaluronidase (permeability), eglins (anti-inflammatory), C1s inhibitor (complement), lipase (vascular protection).

Mandatory safety protocol: Glass vial containment prevents globe migration. Cavernous sinus drainage pathway requires heightened infection surveillance. Anticoagulant screening essential.

No RCTs to date: All evidence Level III-IV. Consistent benefit direction across investigators and institutions supports investigation but does not constitute definitive clinical proof.

References

Bagdasarova, A. V. (1973). On the mechanism of action of leeches. In: Current Issues of Ophthalmology. Tashkent, pp. 50-54.
Bakalova, T. A., Arkhipova, T. V., Bykov, D. V., et al. (2001). Hirudotherapy in the combined treatment of ophthalmological diseases. Proceedings of the 7th Conference of the Hirudologists Association of Russia and CIS Countries, Lyubertsy, pp. 22-23.
Bondareva, V. G. (1998). On the use of hirudotherapy in the late period after acute circulatory disorders of the retina and optic nerve vessels. In: Treatment with Medicinal Leeches and Leech-Derived Preparations, Book II (ed. I. P. Baskova), Moscow, pp. 11-12.
Bondareva, V. G., & Zhitenev, V. M. (1998). Hirudotherapy for urgent ophthalmic pathology based on the experience of a specialized ophthalmologic facility.
Chaban, T. N., & Savinov, V. A. (1995). Hirudotherapy in outpatient ophthalmology.
Dorogova, M. V. (1935). On hirudin and hirudotherapy.
Ivanova, E. G. (1998). Reflexotherapy in chronic vascular pathology of the visual organ.
Kartasheva, E. A. (1979). Effect of leech therapy on the incidence of hyphema in patients operated on for acute angle-closure glaucoma. Transactions of the Institute (Moscow Regional Research Institute), Moscow, 1979, 25, pp. 106-107.
Mozherenkov, V. P., Prokofyeva, G. L., Usova, L. A., & Kharchenko, L. N. (1998). Use of medicinal leeches in the combined treatment of acute angle-closure glaucoma.
Mukhanko, I. Zh., & Kulanin, A. N. (2001). Features of medical rehabilitation of the blind and visually impaired using hirudotherapy at the Mashuk Sanatorium for the Visually Impaired, Pyatigorsk.
Mukhanko, I. Zh., & Kulanin, A. N. (2003). Experience with combined treatment of organic and functional visual impairment at the spa-resort facilities of the Caucasian Mineral Waters using hirudotherapy.
Semikova, T. S. (1998). Leech application in choroidal melanoma radiation complications.
Semikova, T. S., & Bondareva, V. G. (1995). Hirudotherapy in Ophthalmology: methodological guidelines for practitioners.
Semikova, T. S., Semikova, M. V., Yarovoy, A. A., & Timofeev, L. V. (1999). Complications and adverse effects of hirudotherapy in ophthalmology.
Vedeneeva, L. F., & Medvedeva, E. P. (2000). Use of hirudotherapy in subacute thyroiditis, including a case of ophthalmopathy complicating autoimmune thyroiditis.
Yoyleva, S. A., et al. (1999). Combined HT and magnetostimulation for optic neuropathies.

Ophthalmology