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A New Scan May Detect Glaucoma Progression Years Before It Shows Up on a Visual Field Test · Glaucoma, Vision & Longevity: Supplements & Science

• 0:00
  SPEAKER_00: A new scan may detect glaucoma progression years before it shows up on a visual field test.
• 0:06
  SPEAKER_00: Introduction.
• 0:07
  SPEAKER_00: A study published online on September 3, 2026 reported that optical coherence tomography angiography, or OCTIA, detected event-based glaucoma progression an average of 2.3 years before visual field progression.
• 0:21
  SPEAKER_00: Conventional structural optical coherence tomography, or OCT, detected progression about 1.5 years before visual field progression.
• 0:31
  SPEAKER_00: That sounds like a major breakthrough.
• 0:34
  SPEAKER_00: It could imply that clinicians might identify worsening glaucoma long before patients lose measurable vision.
• 0:40
  SPEAKER_00: However, the result needs careful interpretation.
• 0:43
  SPEAKER_00: The study did not prove that OCTIA detects the biological beginning of glaucoma damage two years earlier.
• 0:50
  SPEAKER_00: It showed that an OCETA measurement crossed a predefined statistical threshold before a visual field algorithm crossed its own threshold.
• 0:58
  SPEAKER_00: Those are not necessarily the same thing.
• 1:00
  SPEAKER_00: The most defensible conclusion is, ATTA may provide an earlier vascular signal of progression in some eyes, but the evidence does not yet show that it reliably outperforms the best structural OCT strategy or that every OCT alert represents irreversible retinal ganglion cell loss.
• 1:18
  SPEAKER_00: The new study, what it actually found, study design and participants.
• 1:23
  SPEAKER_00: The study used patients from the Diagnostic Innovations in Glaucoma study, a longitudinal research cohort.
• 1:29
  SPEAKER_00: It included 116 patients, 180 eyes, 111 eyes with parametric glaucoma, meaning repeatable visual field damage was already present.
• 1:38
  SPEAKER_00: 69 preparametric eyes, meaning glaucomatous optic nerve or structural damage was present without repeatable visual field loss.
• 1:45
  SPEAKER_00: Mean age, 67.6 years, mean follow-up 5.1, 1.4 years.
• 1:51
  SPEAKER_00: Minimum eligibility, at least two years of follow-up and at least four visits with each testing method.
• 1:58
  SPEAKER_00: The public abstract does not provide a detailed breakdown into mild, moderate, and advanced glaucoma.
• 2:04
  SPEAKER_00: Therefore, it is not possible to know from the published abstract whether the two-year lead time was concentrated in early disease, moderate disease, advanced disease, or spread evenly across stages.
• 2:16
  SPEAKER_00: JAMA ophthalmology study.
• 2:18
  SPEAKER_00: What was measured?
• 2:19
  SPEAKER_00: The study compared octave vessel density change, circumpapillary retinal nerve fiber layer thickness change, measured by structural OCT, visual field progression.
• 2:31
  SPEAKER_00: The abstract states that OCT and OCTA progression were defined as a change exceeding test-retest variability at two consecutive visits.
• 2:39
  SPEAKER_00: Visual field progression was assessed using the instrument's guided progression analysis.
• 2:44
  SPEAKER_00: Important details are not available in the public abstract.
• 2:47
  SPEAKER_00: The exact OCETA device, the scan size, whether the main metric was peripapillary vessel density, optic nerve head vessel density, macular vessel density, or a combined measure, the exact retinal slab, the numerical test-retest thresholds, whether visual field progression meant possible or likely.
• 3:06
  SPEAKER_00: Guided progression analysis progression.
• 3:08
  SPEAKER_00: Whether the structural OCT algorithm used only event analysis or also a slope-based trend analysis.
• 3:15
  SPEAKER_00: These missing details matter because OCTA vessel density values are highly dependent on the device, scan size, software version, segmentation method, signal strength, and region measured.
• 3:26
  SPEAKER_00: A related 2024 study from the same research group used an OptoView Avanti Angioview system with a 4.5 by 4.5 millimeter optic nerve head scan and a peripapillary annulus.
• 3:39
  SPEAKER_00: But that study should not automatically be assumed to have used the identical protocol.
• 3:43
  SPEAKER_00: Related event-based OCT OCS study, progression detection.
• 3:48
  SPEAKER_00: During follow-up, for the full table, please open this article on VisualFieldTest.com.
• 3:53
  SPEAKER_00: Among the 107 eyes classified as progressing by at least one method, OCTA was the earliest detector in 40 eyes, or 37.4% circumpapillary retinal nerve fiber layer OCT was earliest in 32 eyes or 29.9%.
• 4:08
  SPEAKER_00: Visual field testing was earliest in 26 eyes or 24.3%.
• 4:12
  SPEAKER_00: These figures do not mean that OCTA was correct in 37.4% of all patients.
• 4:17
  SPEAKER_00: They mean that among eyes in which at least one test detected progression, OTA was the first test to cross that study's threshold in about one-third of cases.
• 4:26
  SPEAKER_00: Specificity and false positive rates among 45 eyes considered stable reported specificity was OTA, 68.9%, circumpapillary retinal nerve fiber layer, OCT 75.6%.
• 4:39
  SPEAKER_00: That corresponds to approximate false positive rates of U, 31.1%, or about 14 of the 45 stable eyes, circumpapillary retinal nerve fiber layer, OCT, 24.4%, or about 11 of the 45 stable eyes.
• 4:55
  SPEAKER_00: This is an important limitation.
• 4:56
  SPEAKER_00: The OCT signal appeared earlier, but it was also less specific than the structural OCT measurement.
• 5:03
  SPEAKER_00: The study did not report a conventional sensitivity against an independent gold standard because there is no perfect gold standard for slow glaucoma progression.
• 5:12
  SPEAKER_00: Visual fields cannot serve as a completely independent reference when the question is whether OTA detects change before visual fields.
• 5:19
  SPEAKER_00: The number 58 of 107 progressing eyes, or approximately 54%, is a detection proportion, not a true sensitivity.
• 5:28
  SPEAKER_00: Exact lead time.
• 5:30
  SPEAKER_00: The reported mean lead times were OSTA before visual field progression, 2.3 years, 95% confidence interval, 1.3 to 3.2 years, circumpapillary retinal nerve fiber layer, OCT before visual field progression, 1.5 years, 95% confidence interval, 0.6 to 2.4 years, OCTA versus structural OCT, 0.22 years, 95% confidence interval, minor point six to 0.9 years.
• 5:56
  SPEAKER_00: That last comparison is crucial.
• 5:58
  SPEAKER_00: The study did not show a clear two-year advantage over structural OCT.
• 6:02
  SPEAKER_00: The difference between OCTA and retinal nerve fiber layer OCT was only 0.2 years, and the confidence interval included no difference and even favored structural OCT slightly.
• 6:13
  SPEAKER_00: Therefore, the strongest finding was that OCTA crossed its progression threshold earlier than visual fields.
• 6:20
  SPEAKER_00: The evidence that OCTA is meaningfully earlier than structural OCT is weak.
• 6:25
  SPEAKER_00: Why the two-year advantage should not be accepted at face value?
• 6:29
  SPEAKER_00: It is a comparison of thresholds, not necessarily disease onset.
• 6:33
  SPEAKER_00: Visual field progression is difficult to detect because visual field testing is noisy.
• 6:39
  SPEAKER_00: A test may need several abnormal results before the guided progression analysis labels progression.
• 6:45
  SPEAKER_00: OCETA may therefore appear to lead visual fields for two reasons.
• 6:48
  SPEAKER_00: OCEA detected genuine earlier biological change.
• 6:52
  SPEAKER_00: The visual field required more time and more repeated tests to overcome measurement noise.
• 6:57
  SPEAKER_00: The study cannot fully distinguish these possibilities.
• 7:01
  SPEAKER_00: The definition of progression was not identical across tests.
• 7:04
  SPEAKER_00: OCETA and OCT were considered positive when a measurement exceeded test-retest variability on two consecutive visits.
• 7:12
  SPEAKER_00: Visual fields used guided progression analysis.
• 7:15
  SPEAKER_00: These algorithms ask different questions.
• 7:18
  SPEAKER_00: OCEDA asks whether a quantitative imaging measurement fell beyond an expected repeatability boundary.
• 7:24
  SPEAKER_00: Structural OCT asks whether tissue thickness changed beyond its own boundary.
• 7:29
  SPEAKER_00: Visual field analysis asks whether sensitivity at selected points worsened beyond expected variability.
• 7:36
  SPEAKER_00: A test with a lower threshold or greater biological responsiveness will tend to be classified as earlier, even if it is not more accurate.
• 7:45
  SPEAKER_00: The study was retrospective and based on a referral cohort.
• 7:49
  SPEAKER_00: The diagnostic innovations in glaucoma study is valuable, but it is not a random sample of the general glaucoma population.
• 7:56
  SPEAKER_00: Referral center cohorts often contain more atypical cases, more established glaucoma, more patients with suspicious or borderline findings, more frequent imaging than ordinary clinical practice.
• 8:08
  SPEAKER_00: The results may not apply equally to patients with mild glaucoma, ocular hypertension, high myopia, cataract, diabetes, or poor quality scans.
• 8:17
  SPEAKER_00: The stable group was small.
• 8:19
  SPEAKER_00: The specificity estimate was based on only 45 stable eyes.
• 8:23
  SPEAKER_00: A small change in the number of apparent false positives could substantially change the reported specificity.
• 8:30
  SPEAKER_00: Earlier, did not necessarily mean actionable.
• 8:33
  SPEAKER_00: An OCTA measurement might decline two years before the field crosses a statistical threshold, but the clinician still needs to know: is the decline repeatable?
• 8:42
  SPEAKER_00: Is it topographically consistent with the retinal nerve fiber layer or ganglion cell layer?
• 8:48
  SPEAKER_00: Is it still present after signal strength correction?
• 8:51
  SPEAKER_00: Could it reflect blood pressure, intraocular pressure, medication, or cataract changes?
• 8:56
  SPEAKER_00: Does it predict future visual disability?
• 8:59
  SPEAKER_00: The study did not establish that an OCETA alert should automatically lead to treatment escalation.
• 9:04
  SPEAKER_00: Could the early OCETA signal be an artifact?
• 9:07
  SPEAKER_00: Yes.
• 9:07
  SPEAKER_00: Several explanations are biologically plausible.
• 9:10
  SPEAKER_00: Visual field noise.
• 9:12
  SPEAKER_00: Standard automated perimetry varies because of attention fatigue learning effects, false positive responses, false negative responses, fixation instability, dry eye and blinking, anxiety, advanced damage at the tested location.
• 9:27
  SPEAKER_00: The variability is often greater at already damaged locations.
• 9:31
  SPEAKER_00: Guided progression analysis is designed to reduce false alarms, but false positives still occur.
• 9:36
  SPEAKER_00: In one analysis of stable visual fields, the five-year cumulative false positive rate was approximately 34% for possible progression and 7% for likely progression.
• 9:47
  SPEAKER_00: Global mean deviation and visual field index trend criteria had lower five-year false positive rates of approximately 4% to 5%.
• 9:56
  SPEAKER_00: Visual field progression analysis.
• 9:59
  SPEAKER_00: Functional assessment of glaucoma.
• 10:01
  SPEAKER_00: If a study uses a conservative visual field endpoint, OCTA will naturally appear to lead it more often.
• 10:07
  SPEAKER_00: Regression to the mean.
• 10:08
  SPEAKER_00: Suppose the first OSA scan happens to show unusually low vessel density because of poor focus, mild motion, low blood pressure, or random measurement variation.
• 10:18
  SPEAKER_00: Subsequent scans may move closer to the patient's usual value.
• 10:21
  SPEAKER_00: Conversely, if the first scan is unusually high, later scans may appear to decline.
• 10:27
  SPEAKER_00: This is especially important when the first scan is selected after an abnormal result.
• 10:32
  SPEAKER_00: The patient has only a few baseline scans.
• 10:35
  SPEAKER_00: The normal test-retest range is estimated from a different population.
• 10:39
  SPEAKER_00: The progression algorithm compares every scan with a fixed baseline.
• 10:43
  SPEAKER_00: A same-day duplicate baseline can help identify this problem.
• 10:47
  SPEAKER_00: Signal strength.
• 10:49
  SPEAKER_00: Lower signal strength can make smaller or slower flowing vessels disappear from the OCTIA image.
• 10:54
  SPEAKER_00: A decline in signal strength between visits can therefore look like vessel loss.
• 10:58
  SPEAKER_00: Signal strength can be affected by cataract, posterior capsule opacity, corneal irregularity, tear film instability, vitreous floaters, small pupils, defocus, poor fixation, ocular surface disease.
• 11:13
  SPEAKER_00: OCT reproducibility is generally good under controlled conditions, but intervisit variation is commonly several percentage points and tends to be worse in diseased eyes than healthy eyes.
• 11:23
  SPEAKER_00: Long-term OCTA reproducibility, peripapillary OCTA repeatability, segmentation errors, ochic vascular images by analyzing selected retinal layers.
• 11:34
  SPEAKER_00: If the automated software places the layer boundaries incorrectly, the calculated vessel density may be wrong.
• 11:40
  SPEAKER_00: This is more likely when there is severe glaucoma, retinal nerve fiber layer thinning, peripapillary atrophy, high myopia, disc tilt, retinal pathology, postoperative anatomy, macular distortion.
• 11:54
  SPEAKER_00: A large artifact study in GLUM identified eye movement, defocus, decentration, shadowing, blinking, signal loss, and segmentation errors as common problems.
• 12:02
  SPEAKER_00: OCT artifacts in glaucoma, scan centering differences.
• 12:06
  SPEAKER_00: A small change in where the scan is centered can change the measured vessel density, especially in a narrow sector.
• 12:12
  SPEAKER_00: This is particularly important for the radial peripapillary capillary region, the inferrotemporal sector, the optic nerve head annulus, small macular regions, eyes with a tilted or obliquely inserted optic nerve.
• 12:26
  SPEAKER_00: A scan that is slightly dicentered may sample a different mix of vessels and atrophy, creating an apparent change without true vascular loss.
• 12:34
  SPEAKER_00: Cataract can produce two different types of error.
• 12:38
  SPEAKER_00: It can reduce visual field sensitivity, making glaucoma appear to progress faster.
• 12:43
  SPEAKER_00: It can attenuate OCT and OCTS signals, making vessel density appear lower.
• 12:48
  SPEAKER_00: Studies show that lens opacity can affect quantitative OCTIA measurements, although the size of the effect varies by device and cataract type.
• 12:56
  SPEAKER_00: Media opacity and OCTA vessel density, posterior subcapsular cataract and OCT, cataract-related visual field worsening can be clinically important.
• 13:06
  SPEAKER_00: After cataract surgery, the visual field may improve or the measured rate of decline may change, showing that some apparent progression was caused by the lens rather than the optic nerve.
• 13:17
  SPEAKER_00: Cataract surgery and visual field progression.
• 13:20
  SPEAKER_00: Blood pressure and ocular perfusion pressure.
• 13:23
  SPEAKER_00: OCETA measures a snapshot of flow-related signal.
• 13:27
  SPEAKER_00: Retinal and optic nerve blood flow are influenced by systemic blood pressure, intraocular pressure, ocular perfusion pressure, autoregulation, vascular resistance, time of day orthostatic changes, nocturnal blood pressure lowering.
• 13:42
  SPEAKER_00: A patient scanned after exercise, dehydration, a low blood pressure episode, or a medication change may have a different OCT result without having experienced permanent retinal ganglion cell loss.
• 13:54
  SPEAKER_00: This does not make blood pressure irrelevant.
• 13:56
  SPEAKER_00: Reduced ocular perfusion and impaired vascular autoregulation may contribute to glaucoma damage, especially in normal tension glaucoma.
• 14:05
  SPEAKER_00: But blood pressure is both a potential disease mechanism and a source of measurement variability.
• 14:10
  SPEAKER_00: Ocular perfusion pressure and ocular blood flow, interplay between ocular ischemia and glaucoma, caffeine.
• 14:18
  SPEAKER_00: Caffeine can temporarily alter systemic blood pressure and ocular vascular tone.
• 14:23
  SPEAKER_00: Short-term studies have reported reductions in retinal and choroidal OCTA measurements after caffeinated coffee, although effects vary by study and device.
• 14:33
  SPEAKER_00: Caffeine and OCDA systematic review.
• 14:36
  SPEAKER_00: Caffeinated versus decaffeinated coffee.
• 14:39
  SPEAKER_00: This is unlikely to explain a persistent multi-year decline by itself, but inconsistent caffeine intake could add noise to serial testing.
• 14:47
  SPEAKER_00: For longitudinal monitoring, it is reasonable to perform scans under broadly similar conditions.
• 14:53
  SPEAKER_00: Hydration.
• 14:54
  SPEAKER_00: There is not strong evidence that ordinary day-to-day hydration changes create a two-year-looking OCTIA progression pattern.
• 15:00
  SPEAKER_00: However, dehydration can affect blood pressure, ocular perfusion, intraocular pressure, tear film quality, patient concentration during visual field testing.
• 15:11
  SPEAKER_00: Therefore, hydration is best regarded as a possible minor confounder, not a proven cause of false OCTIA progression.
• 15:17
  SPEAKER_00: Systemic vascular disease, diabetes, hypertension, anemia, sleep apnea, migraine-related vascular dysregulation, kidney disease, and nocturnal hypotension may influence retinal microvasculature.
• 15:30
  SPEAKER_00: A change in systemic vascular health could reduce OCTIA vessel density while also increasing genuine glaucoma risk.
• 15:37
  SPEAKER_00: This creates a difficult interpretation problem.
• 15:40
  SPEAKER_00: The vascular change may be both a confounder and part of the disease process.
• 15:44
  SPEAKER_00: Intraocular pressure variation.
• 15:47
  SPEAKER_00: High intraocular pressure can impair optic nerve perfusion.
• 15:51
  SPEAKER_00: Conversely, pressure lowering may produce a short-term increase in optic nerve head or peripapillary vessel density.
• 15:58
  SPEAKER_00: Studies examining intraocular pressure reduction have found changes in OC to vessel density after treatment.
• 16:04
  SPEAKER_00: These changes may represent improved perfusion or altered flow signal, not regeneration of lost nerve cells.
• 16:11
  SPEAKER_00: Effect of intraocular pressure reduction on OCTA.
• 16:14
  SPEAKER_00: Review of intraocular pressure and medication effects.
• 16:19
  SPEAKER_00: Topical beta blockers, prostaglandin analogs, carbonic anhydrase inhibitors, systemic blood pressure medications, and other treatments may affect intraocular pressure, blood pressure, or vascular tone.
• 16:32
  SPEAKER_00: The exact effect is not consistent enough to correct mathematically in routine practice.
• 16:37
  SPEAKER_00: However, OCETA interpretation should take account of new glaucoma medications, dose changes, medication adherence, systemic beta blockers, antihypertensive changes, recent laser or surgery, device and software variability.
• 16:51
  SPEAKER_00: Absolute vessel density values should generally not be compared between different OCTA manufacturers, different scan sizes, different software versions, different segmentation algorithms, different vessel density definitions.
• 17:05
  SPEAKER_00: A patient should ideally be followed on the same device with the same scan protocol.
• 17:09
  SPEAKER_00: If the device changes, a new baseline may be necessary.
• 17:14
  SPEAKER_00: What does the broader evidence show?
• 17:16
  SPEAKER_00: A 2024 systematic review identified only 10 longitudinal studies examining microvascular OCT changes in glaucoma.
• 17:24
  SPEAKER_00: The studies differed in disease stage, device, scan region, vessel density definition, follow-up duration, and progression method.
• 17:33
  SPEAKER_00: This makes it difficult to combine their lead times into one reliable number.
• 17:37
  SPEAKER_00: Systematic review of longitudinal OCT studies, peripapillary vessel density.
• 17:42
  SPEAKER_00: Pipapillary vessel density measures the capillary network around the optic nerve.
• 17:47
  SPEAKER_00: Lower baseline peripapillary density is associated with worse glaucoma and, in several studies, faster future visual field or retinal nerve fiber layer decline.
• 17:58
  SPEAKER_00: In normal tension glaucoma, a 2024 longitudinal study followed 110 eyes for an average of 5.6 years.
• 18:06
  SPEAKER_00: Eyes with visual field progression had faster peripapillary capillary density loss than eyes without progression.
• 18:12
  SPEAKER_00: However, the difference in vessel density slopes was modest, and the study did not establish that OCT always preceded structural OCT.
• 18:21
  SPEAKER_00: Normal tension glaucoma, longitudinal study, radial parapapillary capillaries.
• 18:27
  SPEAKER_00: The radial parapapillary capillary network lies close to the retinal nerve fiber layer and follows the course of nerve fibers.
• 18:35
  SPEAKER_00: It is biologically attractive because its loss often corresponds to retinal nerve fiber layer damage and visual field defects.
• 18:42
  SPEAKER_00: The limitations are substantial.
• 18:44
  SPEAKER_00: It is sensitive to scan centering.
• 18:46
  SPEAKER_00: It can be affected by peripapillary atrophy.
• 18:49
  SPEAKER_00: It may be difficult to segment in advanced disease.
• 18:52
  SPEAKER_00: Small sector changes can be less reproducible than global measurements.
• 18:56
  SPEAKER_00: Radial peripapillary capillary density may be particularly useful when a vascular defect matches the location of a retinal nerve fiber layer or visual field defect, rather than when it appears as an isolated numerical decline.
• 19:10
  SPEAKER_00: Macular vessel density.
• 19:12
  SPEAKER_00: Macular superficial vessel density may decline relatively early, especially in eyes with central or paracentral glaucoma.
• 19:20
  SPEAKER_00: A longitudinal study of primary open angle glaucoma found that macular superficial vessel density loss was faster than ganglion cell complex thinning during approximately 2.6 years of follow-up.
• 19:32
  SPEAKER_00: More than two-thirds of primary open angle glaucoma eyes had faster macular vessel density decline than ganglion cell complex thinning.
• 19:40
  SPEAKER_00: Macular vessel density and ganglion cell complex.
• 19:44
  SPEAKER_00: This supports the possibility that macular OCTA can show change before a thickness measurement becomes statistically significant, but it does not prove that every macular vessel density change represents future irreversible functional loss.
• 19:58
  SPEAKER_00: Optic nerve head perfusion.
• 20:00
  SPEAKER_00: Optic nerve head capillary density is another promising measurement.
• 20:05
  SPEAKER_00: In a 2024 cohort study of 167 eyes from 109 patients, followed for an average of 5.7 years, faster early optic nerve head capillary density loss was associated with faster subsequent visual field loss.
• 20:21
  SPEAKER_00: Fast OCTIA progressors were approximately twice as likely to develop event-based visual field progression as slow OCTIA progressors.
• 20:29
  SPEAKER_00: Optic nerve head capillary density study, this is better evidence for risk prediction than for a precise two-year lead time.
• 20:37
  SPEAKER_00: Choroidal blood flow and microvascular dropout.
• 20:40
  SPEAKER_00: Deep parapapillary choroidal microvascular dropout has been associated with disc hemorrhage, faster retinal nerve fiber layer loss, and laid later visual field progression.
• 20:50
  SPEAKER_00: However, choroidal OCETA measurements are particularly sensitive to projection artifacts, shadowing, segmentation errors, peripapillary atrophy, high myopia, differences between OCTA devices.
• 21:03
  SPEAKER_00: OCETA also does not directly measure absolute choroidal blood flow.
• 21:07
  SPEAKER_00: It detects motion-related signal from red blood cells and converts that signal into vessel density or flow-related metrics.
• 21:14
  SPEAKER_00: Laser speckle flowography, Doppler methods, and other techniques measure different physiological quantities.
• 21:20
  SPEAKER_00: Therefore, lower vessel density should not automatically be translated into the eye received a specific percentage less blood.
• 21:27
  SPEAKER_00: OCITE and glaucoma, preparametric glaucoma, and microvascular dropout.
• 21:32
  SPEAKER_00: Is reduced perfusion a cause, a consequence, or both?
• 21:36
  SPEAKER_00: The most realistic answer is probably both within a feedback loop.
• 21:40
  SPEAKER_00: Reduced perfusion may cause retinal ganglion cell damage.
• 21:44
  SPEAKER_00: Reduced ocular perfusion can expose the optic nerve and retinal ganglion cells to low oxygen availability, mitochondrial stress, impaired axonal transport, oxidative stress, reduced ability to tolerate intraocular pressure, repeat Ischemia and reperfusion injury.
• 22:02
  SPEAKER_00: This mechanism may be especially relevant in normal tension glaucoma and in patients with vascular dysregulation.
• 22:08
  SPEAKER_00: Reduced perfusion may also appear because damaged cells need less blood flow.
• 22:13
  SPEAKER_00: Blood flow is partly matched to tissue metabolism.
• 22:16
  SPEAKER_00: If retinal ganglion cells and their axons are lost, the remaining tissue may require less oxygen and glucose.
• 22:24
  SPEAKER_00: Some vessel density loss could therefore occur after neuronal damage.
• 22:28
  SPEAKER_00: This interpretation is supported by the fact that OCTI abnormalities often correlate with the amount of existing structural and visual field damage.
• 22:36
  SPEAKER_00: A feedback loop is plausible.
• 22:39
  SPEAKER_00: A likely model is intraocular pressure stress, connective tissue susceptibility, or vascular dysregulation damages vulnerable retinal ganglion cell axons.
• 22:49
  SPEAKER_00: Damaged tissue develops abnormal neurovascular coupling.
• 22:52
  SPEAKER_00: Blood flow regulation becomes less reliable.
• 22:55
  SPEAKER_00: Further hypoxic or metabolic stress makes remaining cells more vulnerable.
• 22:59
  SPEAKER_00: Additional retinal ganglion cell loss causes further vascular remodeling.
• 23:04
  SPEAKER_00: This model explains why OTA can be associated with progression without proving that vessel density loss is always the initiating event.
• 23:12
  SPEAKER_00: Current evidence supports vascular involvement but does not establish a single causal sequence.
• 23:17
  SPEAKER_00: Ocular Perfusion Pressure Review.
• 23:20
  SPEAKER_00: Interplay between ocular ischemia and glaucoma.
• 23:23
  SPEAKER_00: How OTA compares with other tests.
• 23:26
  SPEAKER_00: For the full table, please open this article on VisualFieldTest.com.
• 23:30
  SPEAKER_00: Structural OCT remains highly competitive.
• 23:33
  SPEAKER_00: Longitudinal studies support both macular ganglion cell and peripapillary retinal nerve fiberlayer analysis.
• 23:40
  SPEAKER_00: In some eyes, macular ganglion cell progression occurs first.
• 23:44
  SPEAKER_00: In others, peripapillary retinal nerve fiberlayer progression occurs first.
• 23:48
  SPEAKER_00: Baseline intraocular pressure, disease pattern, optic disc anatomy, and the location of damage influence which parameter changes earliest.
• 23:57
  SPEAKER_00: Macular ganglion cell versus retinal nerve fiber layer progression.
• 24:01
  SPEAKER_00: Integrated macular and peripapillary OCT.
• 24:04
  SPEAKER_00: The 2026 OCTIA study compared OCTA mainly with circumpapillary retinal nerve fiber layer OCT, not with every modern structural strategy.
• 24:13
  SPEAKER_00: It did not establish that OCTA beats.
• 24:15
  SPEAKER_00: Macular ganglion cell interplexiform layer analysis, ganglion cell complex analysis, wide-field retinal nerve fiber layer plus macular analysis, high-density optic nerve head scans, combined structural trend analysis, visual fields remain indispensable.
• 24:32
  SPEAKER_00: OCT can be abnormal before a field defect becomes statistically repeatable, but visual fields remain the test that best describes how glaucoma affects seeing.
• 24:41
  SPEAKER_00: A structural or vascular change should matter clinically only if it eventually relates to a reproducible field defect, a faster future rate of decline, a meaningful change in central or peripheral vision, a treatment decision.
• 24:56
  SPEAKER_00: For central disease, 24-2C and 10-2 testing may be more informative than relying on a global 24-2 mean deviation alone.
• 25:04
  SPEAKER_00: Current clinical guidance continues to regard standard automated perimetry and structural OCT as core components of glaucoma monitoring.
• 25:13
  SPEAKER_00: American Optometric Association Glaucoma Guideline.
• 25:17
  SPEAKER_00: American Optometric Association evidence-based guideline.
• 25:20
  SPEAKER_00: Electrophysiology may detect dysfunction early but is not yet routine.
• 25:25
  SPEAKER_00: Pattern electroretinogram studies suggest that retinal ganglion cell dysfunction can be measurable before conventional visual field defects.
• 25:33
  SPEAKER_00: Long-term studies also suggest that pattern electroretinogram decline and retinal nerve fiber layer decline may provide partly independent information about future field progression.
• 25:45
  SPEAKER_00: However, small longitudinal studies have produced mixed results.
• 25:49
  SPEAKER_00: In one prospective study of 32 patients followed for at least four years, OCT trends were steeper than pattern electroretinogram or photopic negative response trends, and photopic negative response did not significantly worsen in the progressing group.
• 26:05
  SPEAKER_00: Monitoring glaucoma with perimetry, electroretinography, and OCT.
• 26:10
  SPEAKER_00: Long-term pattern electroretinogram monitoring.
• 26:13
  SPEAKER_00: At present, electrophysiology is better viewed as a specialized adjunct than as a replacement for OCT and visual fields.
• 26:20
  SPEAKER_00: Which parameter changes earliest?
• 26:23
  SPEAKER_00: There is no single universal winner.
• 26:25
  SPEAKER_00: The longitudinal evidence suggests the following pattern.
• 26:28
  SPEAKER_00: Macular vessel density can decline before macular thickness in some early eyes.
• 26:33
  SPEAKER_00: Peripapillary and optic nerve head vessel density can predict later visual field progression.
• 26:39
  SPEAKER_00: Macular ganglion cell interplexiform layer and retinal nerve fiber layer often show progression before visual field change and are more clinically validated.
• 26:49
  SPEAKER_00: Ganglion cell analysis may be more useful than global retinal nerve fiber layer in moderate or advanced disease because of the retinal nerve fiber layer floor effect.
• 26:59
  SPEAKER_00: Pattern electroretinogram may show early dysfunction but has not yet demonstrated sufficiently consistent progression performance for routine use.
• 27:08
  SPEAKER_00: Visual fields usually become positive later, but they remain the most directly meaningful functional test.
• 27:16
  SPEAKER_00: My evidence-based ranking would be macular ganglion cell and peripapillary retinal nerve fiber layer OCT together, most validated for routine early structural progression.
• 27:26
  SPEAKER_00: OCT of vessel density trends, potentially earlier in selected eyes, particularly preparametric vascular risk or discordant cases.
• 27:34
  SPEAKER_00: Central visual fields using 24-2C or 10 to 2, essential for detecting functional consequences, particularly when macular damage is suspected.
• 27:44
  SPEAKER_00: Electrophysiology, promising but not yet standardized enough for routine progression decisions.
• 27:50
  SPEAKER_00: Could combining OCEDA, OCT, visual fields, and electrophysiology detect progression earlier?
• 27:56
  SPEAKER_00: Probably, but the improvement is unlikely to be a simple addition of four independent tests.
• 28:02
  SPEAKER_00: The best multimodal strategy would require topographic agreement, not merely multiple abnormal numbers.
• 28:08
  SPEAKER_00: For example, inferior radial peripapillary capillary decline, matching superior retinal nerve fiber layer thinning, corresponding inferior or paracentrov field change, possible ganglion cell interplexiform layer loss.
• 28:22
  SPEAKER_00: When several measurements change in the same anatomical region, the chance that the finding represents genuine glaucoma is much higher.
• 28:29
  SPEAKER_00: A reasonable expectation is OCTA alone may provide an early alert.
• 28:35
  SPEAKER_00: Octoplus macular or peripapillary OCT may provide a more credible structural decision.
• 28:41
  SPEAKER_00: Visual field confirmation determines whether the change is functionally meaningful.
• 28:46
  SPEAKER_00: Electrophysiology may add information in unusual or ambiguous cases, but there is no strong evidence that it routinely adds several additional years of warning.
• 28:55
  SPEAKER_00: The likely benefit is therefore better confidence and earlier risk classification, not necessarily a dramatic four-year lead time.
• 29:03
  SPEAKER_00: Hypothetical monitoring strategies.
• 29:06
  SPEAKER_00: These are evidence-informed strategies, not established universal protocols.
• 29:11
  SPEAKER_00: Early glaucoma or preparametric glaucoma.
• 29:14
  SPEAKER_00: Core testing.
• 29:15
  SPEAKER_00: Structural OCT of the retinal nerve fiber layer and macular ganglion cell layers every 6 to 12 months.
• 29:22
  SPEAKER_00: Standard automated visual field testing every 6 to 12 months.
• 29:26
  SPEAKER_00: Consider 242C or 10-2 testing if the macula or central field is at risk.
• 29:31
  SPEAKER_00: OCTA role.
• 29:32
  SPEAKER_00: One high-quality OCETA scan approximately every 12 months.
• 29:36
  SPEAKER_00: More frequent OCTA, such as every six months, if there is.
• 29:40
  SPEAKER_00: Rapid structural change discomorage, normal tension glaucoma, low ocular perfusion pressure, unexplained disagreement between OCT and visual fields, high-risk microvascular dropout, minimum evidence before calling progression.
• 29:53
  SPEAKER_00: At least four high-quality OCTA scans over approximately 18 to 24 months.
• 29:57
  SPEAKER_00: Two consecutive OCTA changes, stable or comparable signal strength, no major segmentation or centering artifact, preferably matching ganglion cell or retinal nerve fiberlayer change, realistic lead time, raw OCTA.
• 30:09
  SPEAKER_00: Alert, potentially 1 to 2 years before a visual field endpoint.
• 30:14
  SPEAKER_00: More credible, actionable decision, approximately 6 to 18 months earlier.
• 30:19
  SPEAKER_00: OCETA alone should not normally trigger major treatment escalation.
• 30:22
  SPEAKER_00: Estimated false alarm probability.
• 30:25
  SPEAKER_00: An isolated OCTIA event, potentially around 20% to 30%, using the 2026 study's false positive like rate as a conservative warning.
• 30:34
  SPEAKER_00: Two consecutive high-quality OCETA changes with matching OCT abnormality, an informed estimate of approximately 5% to 10% over several years, but this has not been validated prospectively.
• 30:46
  SPEAKER_00: Moderate glaucoma, core testing, structural OCT every six months, visual field testing every six months, alternating or combining 24-2, 24-2C, and 10-2 according to the defect OCTA every 6 to 12 months if the disease is progressing or the retinal nerve fiber layer is approaching its floor.
• 31:06
  SPEAKER_00: OCTA role.
• 31:07
  SPEAKER_00: Focus on radial peripapillary capillaries, peripapillary density, macular superficial vessel density, optic nerve head capillary density, realistic lead time, usually 3 to 12 months of additional actionable warning after repeat confirmation.
• 31:23
  SPEAKER_00: A two-year lead may occur in selected patients but should not be assumed.
• 31:28
  SPEAKER_00: Estimated false alarm probability.
• 31:30
  SPEAKER_00: OCTA alone, potentially 20% or higher.
• 31:33
  SPEAKER_00: OCA plus matching ganglion cell or retinal nerve fiber layer progression, likely substantially lower, perhaps 5-10%, but still an estimate.
• 31:43
  SPEAKER_00: Advanced glaucoma, core testing, visual field testing every 3 to 6 months, often greater emphasis on 10 to 2 testing, macular ganglion cell analysis, and wide field structural OCT.
• 31:54
  SPEAKER_00: Careful optic nerve examination and photographs.
• 31:57
  SPEAKER_00: OCETA role.
• 31:58
  SPEAKER_00: OCETA may be useful when the circumpapillary retinal nerve fiber layer is at its floor.
• 32:03
  SPEAKER_00: Remaining macular tissue can still be measured.
• 32:06
  SPEAKER_00: Visual fields are unreliable.
• 32:08
  SPEAKER_00: There is concern about vascular dysregulation.
• 32:11
  SPEAKER_00: However, advanced glaucoma also creates more segmentation artifacts, peripapillary atrophy, and low signal.
• 32:18
  SPEAKER_00: Global vessel density values should not be interpreted in isolation.
• 32:22
  SPEAKER_00: Realistic lead time, often 0 to 12 months, not reliably 2 years.
• 32:27
  SPEAKER_00: The practical goal is confirming change early enough to preserve remaining central or peripheral vision.
• 32:33
  SPEAKER_00: After successful trabeculectomy with very low intraocular pressure, immediately after surgery, OCTA changes may reflect altered hemodynamics rather than disease progression.
• 32:44
  SPEAKER_00: A cautious strategy would be: do not use the first immediate postoperative scan as the long-term baseline.
• 32:50
  SPEAKER_00: Establish a new baseline after intraocular pressure and anatomy have stabilized, often around one to three months, depending on clinical circumstances.
• 33:00
  SPEAKER_00: Repeat OCT and visual field testing at approximately 3, 6, and 12 months, then adjust according to risk.
• 33:08
  SPEAKER_00: Record intraocular pressure, blood pressure, medication changes, and postoperative complications at each imaging visit.
• 33:15
  SPEAKER_00: If OCTA vessel density changes rapidly after surgery, determine whether the change is reversible and whether it matches retinal nerve fiber layer, ganglion cell, or field change.
• 33:26
  SPEAKER_00: A rise in vessel density after pressure reduction should not be interpreted as regeneration of retinal ganglion cells.
• 33:33
  SPEAKER_00: A fall in density shortly after surgery should not automatically be labeled progression.
• 33:38
  SPEAKER_00: If glaucoma continues to progress despite very low intraocular pressure, clinicians may need to consider nocturnal hypotension, orthostatic blood pressure drops, sleep apnea, anemia, vascular dysregulation, disc hemorrhage, incorrect intraocular pressure measurement, ongoing pressure spikes not captured during office visits.
• 33:59
  SPEAKER_00: How many OCT scans are needed?
• 34:01
  SPEAKER_00: The 2026 study required at least four visits with each modality.
• 34:06
  SPEAKER_00: Based on that design and the known variability of OCTIA, a practical research quality approach would be two baseline quality scans, preferably close together, at least three additional scans, the same instrument and software, the same scan size and location, manual review of segmentation and image quality, a minimum of two consecutive changes before labeling progression.
• 34:29
  SPEAKER_00: For routine practice, four to six high-quality OCTIA scans over 18 to 36 months would provide a much more credible trend than two isolated measurements.
• 34:39
  SPEAKER_00: Scanning every three months may reduce time to detection but increases cost and creates more opportunities for false positive fluctuations.
• 34:48
  SPEAKER_00: For many stable early glaucoma patients, every 6 to 12 months is more reasonable.
• 34:54
  SPEAKER_00: Probability estimates.
• 34:56
  SPEAKER_00: These estimates are informed judgments rather than results from a validated prediction model.
• 35:01
  SPEAKER_00: Probability that an approximately two-year OC to lead will replicate.
• 35:06
  SPEAKER_00: Probability that OTA shows earlier statistical change than visual fields in at least some independent cohorts, approximately 70%, probability that the average lead time is at least two years, approximately 40 to 50%.
• 35:20
  SPEAKER_00: Probability that the exact 2.3 year estimate applies broadly across routine patients, approximately 25% to 35%.
• 35:28
  SPEAKER_00: The direction of the finding is more likely to replicate than the exact magnitude.
• 35:32
  SPEAKER_00: Probability that OCETA becomes routine progression monitoring within five years.
• 35:37
  SPEAKER_00: By September 8, 2031, my estimate is routine OCETA monitoring in selected glaucoma specialty practices, 40 to 50%, routine OCTA for most glaucoma patients, 20 to 30% OCETA becoming a universally required standard alongside OCT and visual fields, less than 20%.
• 35:56
  SPEAKER_00: Adoption will depend on device standardization, reimbursement, automated artifact correction, a validated progression algorithm, independent multi-center replication, evidence that OCTA-guided treatment actually preserves vision, probability that OCTA adds useful information beyond structural OCT.
• 36:15
  SPEAKER_00: In all glaucoma patients, approximately 35% to 50%.
• 36:19
  SPEAKER_00: In preparimetric, normal tension, vascular risk, or discordant cases, approximately 60% to 75%.
• 36:27
  SPEAKER_00: In advanced glaucoma with a retinal nerve fiber layer floor, approximately 50% to 65%, provided image quality is good.
• 36:34
  SPEAKER_00: Probability that OCTA outperforms structural monitoring as a replacement for retinal nerve fiber layer and ganglion cell OCT across all disease stages, less than 20%, as a supplement that sometimes detects a different or earlier signal, approximately 70% to 85%, as the best single test for glaucoma progression?
• 36:54
  SPEAKER_00: Unlikely.
• 36:55
  SPEAKER_00: If OCTA really gives a two-year warning, should glaucoma monitoring change?
• 36:59
  SPEAKER_00: Yes, but selectively, not by replacing current tests.
• 37:03
  SPEAKER_00: The new evidence supports adding OCTIA when the patient has preparametric glaucoma, normal tension glaucoma, disc hemorrhage, vascular risk factors, rapid or unexplained structural change, discordant OCT and visual field results, advanced disease with a retinal nerve fiber layer floor, but an isolated OCTA decline should usually lead to repeat imaging, careful review of signal strength, segmentation, motion, and scan centering comparison with macular ganglion cell and retinal nerve fiberlayer OCT.
• 37:34
  SPEAKER_00: Repeat visual field testing, especially 24-2C or 10-2 when central damage is possible.
• 37:40
  SPEAKER_00: Review of intraocular pressure, blood pressure, medications, cataract, and systemic vascular factors.
• 37:47
  SPEAKER_00: It should not automatically lead to surgery, additional medication, or a diagnosis of irreversible progression.
• 37:53
  SPEAKER_00: The strongest present-day interpretation is Okta is a promising early warning and risk stratification tool.
• 38:01
  SPEAKER_00: It may detect vascular change before visual field progression in some eyes, but its apparent two-year advantage is partly influenced by visual field noise, test definitions, and OC to measurement variability.
• 38:13
  SPEAKER_00: Its advantage over the best structural OCT strategy remains unproven.
• 38:18
  SPEAKER_00: For now, the most reliable approach is a multimodal strategy.
• 38:22
  SPEAKER_00: Structural OCT of both the retinal nerve fiber layer and macular ganglion cell layers.
• 38:28
  SPEAKER_00: Appropriate visual field testing, including 24-2C or 10-2 when indicated, OCT when vascular information could resolve uncertainty.
• 38:36
  SPEAKER_00: Electrophysiology only in selected specialist cases.
• 38:40
  SPEAKER_00: OC should therefore supplement, not replace, structural OCT in visual fields.
• 38:45
  SPEAKER_00: It may eventually become especially valuable for identifying eyes that need closer surveillance before conventional functional loss is measurable.
• 38:53
  SPEAKER_00: But a genuine two-year clinical advantage still requires independent replication and proof that acting on the OCTA signal improves patient outcomes.
• 39:03
  SPEAKER_00: All links to sources are available in the text version of this article.
• 39:07
  SPEAKER_00: You can find the full article at VisualFieldTest.com.
• 39:12
  SPEAKER_00: Thanks for listening.
• 39:13
  SPEAKER_00: To check your visual field, click the link at the bottom of this article or visit visualfieldtest.com.