Management of High Myopia with Retinal Thinning and Normal IOP
Your IOP levels of 17-18 mmHg are within normal range, and the inferior-temporal (I-T) retinal thinning you describe is most likely a benign anatomical variant related to your tilted optic disc from high myopia rather than glaucomatous damage—therefore, observation without IOP-lowering treatment is appropriate at this time. 1, 2
Understanding Your Disc Appearance
Tilted discs are a characteristic feature of high myopia, not glaucoma. In high myopia, particularly in normal-tension glaucoma patterns, smaller and tilted discs are the defining characteristics, with disc tilt specifically associated with inferior retinal nerve fiber layer (RNFL) changes 2. Your temporal slope changes and the I-T region thinning align with the morphometric changes expected in myopic eyes with tilted discs 3.
The key distinguishing features include:
- Tilted discs in high myopia cause indistinct rim-cup borders, making it difficult to assess true glaucomatous cupping 3
- The tilt ratio decreases significantly in high myopic eyes (0.73±0.09 in high myopia versus 0.80±0.09 in non-high myopia), and this tilt is specifically associated with lower/inferior RNFL changes 2
- Your IOP values of 17-18 mmHg fall well below treatment thresholds for glaucoma suspects 1
Risk Assessment and Monitoring Strategy
You should be monitored as a glaucoma suspect given your high myopia, but not treated at current IOP levels. Myopia is an established risk factor for primary open-angle glaucoma (POAG), but treatment decisions depend on multiple factors beyond just disc appearance 1.
When to Consider Treatment
Treatment would be indicated if you develop 1:
- Documented optic nerve deterioration on serial imaging (not just static anatomical variants)
- Confirmed visual field defects consistent with glaucoma (not the pseudo-defects from tilted disc syndrome)
- IOP consistently above 24-26 mmHg with additional risk factors 1
If treatment were initiated, target IOP would be 20% below baseline, which in your case would mean targeting approximately 13-14 mmHg 1. However, this is not indicated based on your current presentation.
Critical Pitfall: Tilted Disc Syndrome and False Visual Field Defects
Be aware that tilted disc syndrome can create false visual field defects that mimic glaucomatous progression. Upper temporal visual field defects are characteristic of tilted disc syndrome, and these defects can partly or totally disappear with increased myopic correction (mean improvement of 17.0±6.2 degrees with additional 3.1±1.5 D myopic correction) 4.
Any visual field testing you undergo must use the myopic correction that provides maximal improvement to prevent false interpretation of field deterioration 4. This is essential because even small changes in near correction during examination can falsely suggest worsening or improving defects 4.
Recommended Monitoring Protocol
Follow-up frequency should be every 6-12 months for high-risk glaucoma suspects 5. Your comprehensive evaluation should include:
- Serial optic disc photography to document stability versus true progression 1, 5
- OCT imaging of RNFL and macula to distinguish static myopic changes from progressive glaucomatous loss 1
- Visual field testing with optimized myopic correction to avoid false defects from tilted disc 4
- IOP measurement at each visit 5
- Central corneal thickness measurement as a baseline risk factor 5
Long-term Considerations for High Myopia
Your high myopia places you at increased risk for multiple complications beyond glaucoma, including progressive retinal and choroidal thinning, peripheral retinal degeneration, retinal detachment, and myopic choroidal neovascularization 1. The I-T thinning you describe is part of the natural history of high myopia, where progressive retinal and choroidal thinning occurs over time 1.
Lowering IOP in high myopia may theoretically slow axial elongation by reducing scleral remodeling and improving choroidal perfusion, but this remains investigational and is not an indication for treatment in your case with normal IOP 6.
Risk Calculator Utilization
Consider using the OHTS risk calculator (available at https://ohts.wustl.edu/risk/) to quantify your 5-year risk of conversion to glaucoma using your age, cup-to-disc ratio, visual field pattern standard deviation, central corneal thickness, and IOP 1, 5. This provides objective risk stratification to guide monitoring intensity.