Eye SchoolUrgent

This site provides general eye-health education. It cannot replace individual assessment by a registered doctor, and does not offer personal diagnosis, prescriptions, bookings, sales or referrals.

If translations differ or are incomplete, the Traditional Chinese (zh-Hant) text on this site prevails.

Glaucoma visual-field illustration

Pick a stage

A street scene to show roughly how glaucomatous field loss can look from mild to end-stage. Most glaucoma progresses slowly and many people notice nothing early on. Lost field does not come back; treatment aims to slow further loss.

Choose a stage

Simulation · Right eye · Mild · Arcuate

When both eyes are open, the other eye often fills in the gap, so many people notice nothing at all — it takes an eye examination to find it.

Mild

What it can look like: Small, shallow patches of blur or dimming (often nasal, or arch-shaped above or below fixation). Central vision is usually still sharp. The brain fills the gaps in, so most people do not notice.

HPA early — mean deviation (MD) on a field report better than about −6 dB, with central 5° test points still normal.

Often no symptoms at all; found by an eye examination (pressure, optic-nerve OCT, visual field). A small histology study (17 donor eyes) found that by the time automated field testing is statistically abnormal, roughly 25–35% of retinal ganglion cells are typically already lost (Kerrigan-Baumrind 2000).

Pattern (three simplified types)

Follows nerve-fibre bundles, curving from near the blind spot toward the nasal side as an arch-shaped dim band, often stopping abruptly at the horizontal midline.

Real fields can mix patterns, and other types such as paracentral loss exist; this is simplified.

Display style

Do patients really see black?

In a study of 50 people with glaucoma, none picked a “black tunnel” or “black patches” to represent their vision; 54% picked “blurred patches”, 16% “missing patches”, and 26% were completely unaware of their field loss (Crabb 2013). So the default uses blur, fading and “fill-in” from surroundings rather than black.

Most describe blur, haze, needing more light, or parts “missing”; some notice nothing. With both eyes open the brain often compensates, so a one-eye defect is even harder to notice (a common observation, not specific to this site).

Grey-scale field chart (illustration)Darker = lower sensitivity in that area. Field reports have a similar grey-scale chart, but a real report is measured by an instrument and is not this picture. The small dark square on the right is the normal blind spot everyone has.
Sudden vision loss, severe eye pain, or headache with nausea → urgent page
What studies say about eye pressure (group-level figures)

This is not your prognosis and not a prediction. The slider only shows what published studies reported around that pressure; it does not calculate your risk and cannot replace an ophthalmologist setting your target pressure.

Pressure level is not the same as “stage”: some people have glaucoma with pressure always in the statistically normal range (normal-tension), and some have raised pressure for years with a healthy optic nerve (ocular hypertension).

20 mmHg

10–35 mmHg; used only to look up study ranges. It does not change the field picture above.

EMGT
OHTS
UKGTS

Where each study's pressures sit · EMGT: entry pressure ≤ 30; median 20 · OHTS: entry pressure about 24–32 · UKGTS: baseline mean about 20 · 18: AGIS report 7 grouping cut-off

Study figures for this pressure range

About 18–21 mmHg

  • About 18–21 mmHg is the upper part of the commonly used “statistically normal” range (usual upper limit about 21 mmHg; it is not one line for everyone).
  • EMGT (early open-angle glaucoma, median baseline pressure 20 mmHg): each 1 mmHg higher mean pressure during follow-up was associated with about 13% higher progression risk (HR 1.13, 95% CI 1.07–1.19). Treatment lowered pressure by 5.1 mmHg (25%) on average; progression at a median of about 6 years: 45% treated vs 62% control.
  • UKGTS (newly diagnosed open-angle glaucoma, baseline mean pressure about 20 mmHg): risk of field deterioration within 24 months, pressure-lowering drops (a prostaglandin analogue) vs placebo, HR 0.44 (95% CI 0.28–0.69); mean pressure fall 3.8 vs 0.9 mmHg.

Speed of progression varies between people: in a routine clinical-care study (583 people with open-angle or pseudoexfoliation glaucoma, mean follow-up 7.8 years) the mean field MD slope was −0.80 dB per year (very variable; 5.6% progressed faster than −2.5 dB per year); higher mean pressure and older age were associated with faster progression (Heijl 2013).

Event rates reported by the studies (control vs treated)

  • EMGT: progression at median about 6 y

    Control
    62%
    Treated
    45%

  • OHTS: open-angle glaucoma by 5 y

    Observed
    9.5%
    Medication
    4.4%

Populations, outcome definitions, treatments and follow-up differ between studies, so bars from different studies must not be compared. Figures are group results, not a personal prognosis and not a promise of treatment effect.

This tool has no personal pressure or medical-record data, is not connected to live patient data, does not calculate a risk for the slider value, and does not extrapolate the studies' per-mmHg risk to other ranges, because that would give a precise-looking number the studies do not support.

Selected public references (not a full bibliography)

These are the public studies this page draws on. PMID links go to PubMed (US National Library of Medicine) so you can check them. Figures are from those studies — not your prognosis and not a clinic success rate. Links are not a shop.

  1. Crabb DP, Smith ND, Glen FC, Burton R, Garway-Heath DF. How does glaucoma look?: patient perception of visual field loss. Ophthalmology. 2013;120(6):1120-1126. PMID 2341542150 位患者：無人選黑色隧道／黑色斑塊；54% 選模糊斑塊、16% 選缺失斑塊；26% 完全不知道。小型橫斷面研究。
  2. Hu CX, Zangalli C, Hsieh M, et al. What do patients with glaucoma see? Visual symptoms reported by patients with glaucoma. Am J Med Sci. 2014;348(5):403-409. PMID 2499239299 位患者問卷：最常見是需要更多光線及視物模糊；視野損失較多者較難看到兩側。
  3. Kerrigan-Baumrind LA, Quigley HA, Pease ME, Kerrigan DF, Mitchell RS. Number of ganglion cells in glaucoma eyes compared with threshold visual field tests in the same persons. Invest Ophthalmol Vis Sci. 2000;41(3):741-748. PMID 1071168917 隻捐贈眼：自動視野出現統計異常時，已有約 25–35% 視網膜神經節細胞流失。小型組織學研究。
  4. Kastner A, King AJ. Advanced glaucoma at diagnosis: current perspectives. Eye (Lond). 2020;34(1):116-128. PMID 31740802HPA 準則表（MD 約 −6／−12 dB）及「晚期」常用定義；部分外科文獻以 MD 差過約 −20 dB 為晚期。
  5. Brusini P, Johnson CA. Staging functional damage in glaucoma: review of different classification methods. Surv Ophthalmol. 2007;52(2):156-179. PMID 17355855視野分級方法綜述（含 Hodapp–Parrish–Anderson 準則）。
  6. Mills RP, Budenz DL, Lee PP, et al. Categorizing the stage of glaucoma from pre-diagnosis to end-stage disease. Am J Ophthalmol. 2006;141(1):24-30. PMID 16386972以 Hodapp–Parrish–Anderson 為基礎、由前期至末期共六級的視野分期系統。
  7. AGIS Investigators. Advanced Glaucoma Intervention Study. 2. Visual field test scoring and reliability. Ophthalmology. 1994;101(8):1445-1455. PMID 7741836AGIS 視野缺損分數 0–20 的定義。
  8. Garway-Heath DF, Poinoosawmy D, Fitzke FW, Hitchings RA. Mapping the visual field to the optic disc in normal tension glaucoma eyes. Ophthalmology. 2000;107(10):1809-1815. PMID 11013178視野位置與視盤扇區的對應，解釋弓形缺損沿神經纖維走向。
  9. Heijl A, Leske MC, Bengtsson B, et al. Reduction of intraocular pressure and glaucoma progression: results from the Early Manifest Glaucoma Trial. Arch Ophthalmol. 2002;120(10):1268-1279. PMID 12365904早期開角型青光眼：降眼壓減慢惡化。已失視野不能還原。
  10. Leske MC, Heijl A, Hussein M, et al. Factors for glaucoma progression and the effect of treatment: the early manifest glaucoma trial. Arch Ophthalmol. 2003;121(1):48-56. PMID 12523884EMGT：隨訪平均眼壓每高 1 mmHg，進展 HR 1.13；治療組進展風險約為對照一半。群體結果，不是個人預後。
  11. Leske MC, Heijl A, Hyman L, et al. Predictors of long-term progression in the early manifest glaucoma trial. Ophthalmology. 2007;114(11):1965-1972. PMID 17628686EMGT 長期隨訪（至 11 年）：治療及隨訪眼壓持續影響進展；年齡、雙眼、剝脫、視盤出血等亦有關。
  12. AGIS Investigators. The Advanced Glaucoma Intervention Study (AGIS): 7. The relationship between control of intraocular pressure and visual field deterioration. Am J Ophthalmol. 2000;130(4):429-440. PMID 11024415手術後開角型青光眼：每次覆診眼壓 <18 mmHg 的眼，視野分數平均變化接近 0；不足一半覆診 <18 的估計平均惡化 0.63 分（p=0.083）。關聯性分析，不是個人預後。
  13. Collaborative Normal-Tension Glaucoma Study Group. Comparison of glaucomatous progression between untreated patients with normal-tension glaucoma and patients with therapeutically reduced intraocular pressures. Am J Ophthalmol. 1998;126(4):487-497. PMID 9780093CNTGS: pressure lowered by 30%; eyes reaching the endpoint 12% in the treated group vs 35% in controls. The intention-to-treat analysis (PMID 9780094) showed no significant difference; the difference only appeared after cataract effects were removed. Group result, not a personal prognosis.
  14. Collaborative Normal-Tension Glaucoma Study Group The effectiveness of intraocular pressure reduction in the treatment of normal-tension glaucoma. Am J Ophthalmol. 1998;126(4):498-505. PMID 9780094The intention-to-treat analysis showed no significant difference; after censoring cataract effects, the group with pressure lowered by about 30% worsened less. Surgery caused more cataract, so whether to lower pressure aggressively needs individual assessment.
  15. Kass MA, Heuer DK, Higginbotham EJ, et al. The Ocular Hypertension Treatment Study: a randomized trial determines that topical ocular hypotensive medication delays or prevents the onset of primary open-angle glaucoma. Arch Ophthalmol. 2002;120(6):701-713. PMID 12049574五年累積轉成開角型青光眼：用藥組 4.4%，觀察組 9.5%。不是人人必須即時用藥。
  16. Garway-Heath DF, Crabb DP, Bunce C, et al. Latanoprost for open-angle glaucoma (UKGTS): a randomised, multicentre, placebo-controlled trial. Lancet. 2015;385(9975):1295-1304. PMID 25533656新診斷開角型青光眼，24 個月視野惡化：降眼壓滴眼藥對安慰劑 HR 0.44。群體結果，不是個人預後。
  17. Heijl A, Buchholz P, Norrgren G, Bengtsson B. Rates of visual field progression in clinical glaucoma care. Acta Ophthalmol. 2013;91(5):406-412. PMID 23066646583 人臨床常規照顧：MD 平均每年 −0.80 dB，個別差異大；較高平均眼壓與較快進展相關。
青光眼專題

A demonstration is not an examination and cannot replace dilated fundus exam, visual field or OCT. A normal result here does not rule out disease. New changes need prompt review by a registered ophthalmologist; sudden vision loss — go to A&E. This site does not book or refer.