Why Shibas Are at Risk for Glaucoma
Shiba Inus have a documented breed predisposition to primary glaucoma, particularly primary angle-closure glaucoma (PACG). Studies in Japan show Shibas have one of the highest incidences among all breeds.
Key Statistics
| Metric | Value | |--------|-------| | Breed incidence | 5-7% (vs 0.5-1% general population) | | Type | Primary angle-closure (most common) | | Average onset age | 7-10 years | | Bilateral risk | 50% develop in second eye within 8 months | | Blindness risk | High without early treatment |Key Statistics & Research Data
Shiba Inus have the highest breed prevalence of primary glaucoma among breeds studied in Japan, with approximately 33% of affected dogs developing the condition — significantly higher than other breeds (Source: Kanemaki et al., Journal of Veterinary Medical Science, 2006).
Primary angle-closure glaucoma with goniodysplasia (abnormal drainage angle development) is the predominant form in Shiba Inus, with bilateral involvement occurring in 50-65% of cases within 8-12 months of initial diagnosis (Source: Kanemaki et al., J Vet Med Sci, 2006; Gelatt & MacKay, Veterinary Ophthalmology, 2004).
A 2026 study identified the SIX6 gene as a major glaucoma risk locus in Shiba Inus, with the same gene previously linked to human primary open-angle glaucoma — representing a rare cross-species genetic parallel (Source: PMC, 'Genetic Link Across Species: SIX6,' 2026).
Intraocular pressure (IOP) above 30 mmHg constitutes a veterinary emergency, with irreversible retinal damage occurring within 24-72 hours — [Shiba Inu](https://seniorpet.org/knowledge/breed/shiba-inu "Senior Shiba Inu Health Guide") owners should be educated on early signs (eye redness, cloudiness, pain) for emergency intervention (Source: Gelatt & MacKay, Veterinary Ophthalmology, 2004).
Understanding Glaucoma
What Happens
- Aqueous humor (fluid inside eye) cannot drain properly
- Intraocular pressure (IOP) increases
- Pressure damages optic nerve and retina
- Vision loss occurs — initially peripheral, then total
- Can progress rapidly (hours to days in acute cases)
Types in Shibas
| Type | Mechanism | Prognosis | |------|-----------|----------| | Primary angle-closure | Drainage angle physically blocked | Guarded — requires lifelong management | | Primary open-angle | Drainage tissue dysfunction | Better — slower progression | | Secondary | Caused by other eye disease | Depends on underlying cause |Early Warning Signs
Subtle Signs (Often Missed)
- Slight redness in one eye
- Mild cloudiness or haziness
- Pupil slightly larger in one eye
- Squinting or avoiding bright light
- Rubbing eye on furniture
- Subtle behavior changes (bumping into things on one side)
Acute Glaucoma Emergency
- Sudden severe eye pain (pawing at eye, head pressing)
- Eye appears swollen or bulging
- Cornea turns blue/cloudy
- Pupil fully dilated and fixed
- Tearing, squinting
- Loss of appetite, lethargy from pain
- THIS IS AN EMERGENCY — seek veterinary care within hours
Diagnosis
Tonometry (IOP Measurement)
- Normal IOP: 10-25 mmHg
- Glaucoma suspected: >25 mmHg
- Glaucoma confirmed: >30 mmHg
- Acute crisis: often >40-60 mmHg
Additional Tests
- Gonioscopy (examines drainage angle)
- Fundoscopy (evaluates optic nerve/retina)
- Ultrasound (if cornea too cloudy to see through)
- Electroretinography (ERG — tests retinal function)
Treatment
Emergency (Acute Glaucoma)
- IV mannitol to rapidly reduce IOP
- Topical prostaglandin analogs (latanoprost)
- Topical carbonic anhydrase inhibitors
- Topical beta-blockers
- Pain management
- Goal: reduce IOP within 1-2 hours
Long-Term Medical Management
| Medication | Mechanism | Frequency | |-----------|-----------|----------| | Dorzolamide | Reduces fluid production | 2-3x daily | | Timolol | Reduces fluid production | 2x daily | | Latanoprost | Increases fluid drainage | 1-2x daily | | Combination drops | Multiple mechanisms | 2-3x daily |Surgical Options
| Procedure | Purpose | Notes | |-----------|---------|-------| | Laser cyclophotocoagulation | Destroy fluid-producing cells | Can be repeated | | Gonioimplant (shunt) | Create new drainage pathway | Requires monitoring | | Enucleation (eye removal) | Pain relief for blind eye | Definitive solution for painful blind eye | | Intravitreal injection | Chemical ablation | For blind, painful eyes |Monitoring Protocol for At-Risk Shibas
Recommended Schedule
- Annual eye exams starting at age 5
- Biannual IOP checks starting at age 7
- Immediate exam if any eye changes noted
- Prophylactic treatment for second eye when first is diagnosed
Living with a Blind Shiba
- Shibas adapt well to blindness due to strong other senses
- Keep furniture layout consistent
- Use scent markers at doorways
- Verbal cues replace visual ones
- Maintain exercise with leash guidance
- Most blind Shibas maintain good [quality of life](https://seniorpet.org/knowledge/[siamese](https://seniorpet.org/knowledge/breed/siamese "Senior Siamese Cat Health Guide")-cat-quality-of-life "Quality of Life Assessment")
Key Takeaways
- Shiba Inus have 5-7% glaucoma incidence, among the highest of all breeds
- Primary angle-closure glaucoma is most common, typically appearing at 7-10 years
- Acute glaucoma is an emergency — seek care within hours to save vision
- If one eye is affected, 50% chance the second eye develops glaucoma within 8 months
- Regular IOP monitoring starting at age 7 enables early detection
- Blind Shibas can maintain excellent quality of life with environmental adaptations