Heightened visual light sensitivity discomfort measured by the ocular photosensitivity analyzer is associated with chronic ocular pain, 2025, Karakole

[Dolphin]

https://www.sciencedirect.com/science/article/abs/pii/S1542012425000850

The Ocular Surface​

Volume 38, October 2025, Pages 64-71

Heightened visual light sensitivity discomfort measured by the ocular photosensitivity analyzer is associated with chronic ocular pain​

Ema V. Karakoleva a b c, Nicholas Pondelis d, Cameron Talbert d, Mariela C. Aguilar b e, Alex Gonzalez b e, Cornelis Rowaan b e, Heather Durkee b e, Paula A. Sepulveda-Beltran a b, David Valdes-Arias a b, Chloe Shields a b, Shreya Bhatt a b, David Zurakowski f, Deborah S. Jacobs g, Joseph B. Ciolino g, Elizabeth R. Felix h, Jean-Marie Parel b e, Eric A. Moulton d i, Anat Galor a b

Cite
https://doi.org/10.1016/j.jtos.2025.06.007

Highlights​

• •
  Individuals with chronic ocular pain show lower visual sensitivity discomfort threshold than those without ocular pain, corresponding to heightened photoallodynia.
• •
  Automated testing quantifies visual light discomfort thresholds.
• •
  Self-reported photoallodynia aligns with measured discomfort levels.
• •
  Fibromyalgia and chronic fatigue syndrome predict lower light discomfort thresholds.

Abstract​

Purpose​

To quantify visual photosensitivity discomfort thresholds (VPDT) in individuals with chronic ocular pain (COP) compared to controls without COP and explore relationships between VPDT, demographics, clinical factors, and ocular metrics.

Methods​

Prospective case-control study of 75 participants: 36 with COP (age 46.5 ± 15.6 years; 56 % female) and 39 controls (39.2 ± 15.6 years; 56 % female). COP was defined by self-reported ocular pain intensity ≥15 on a numerical rating scale (range, 0–100) for ≥3 months. COP cases were subclassified into inflammatory (Sjögren's disease) and neuropathic ocular pain subgroups. VPDT was measured using the Ocular Photosensitivity Analyzer (OPA), and ocular symptoms were assessed using the Visual Light Sensitivity Questionnaire (VLSQ-8; 8–40) and Ocular Surface Disease Index (OSDI; 0–100), with OSDI Question 1 addressing light sensitivity (OSDI-Q1; 0–4).

Results​

COP patients exhibited lower VPDT than controls (log lux, 1.60 ± 1.17 vs. 2.42 ± 1.05; P = 0.006), indicating greater photosensitivity discomfort. No differences in VPDT were seen across COP subtypes. COP patients also reported greater symptom severity than controls, with higher VLSQ-8 (21.92 ± 1.41 vs. 9.03 ± 0.53), OSDI (50.84 ± 3.88 vs. 2.82 ± 0.85), and OSDI-Q1 (2.00 ± 0.24 vs. 0.14 ± 0.06) scores (all P < 0.001). VPDT negatively correlated with VLSQ-8 (ρ = −0.75) and OSDI-Q1 (ρ = −0.62), demonstrating alignment between subjective light sensitivity symptoms and OPA-measured photosensitivity discomfort. Multivariable regression identified fibromyalgia as the strongest predictor of VPDT (19.6 % variance explained), with chronic fatigue improving the model (26.5 %).

Conclusion​

COP subjects display greater photosensitivity-related discomfort than controls, highlighting the OPA's potential as a psychophysical tool for quantifying photoallodynia. Further research is needed to assess its diagnostic utility across COP subtypes.

 

[Utsikt]

COP subjects display greater photosensitivity-related discomfort than controls, highlighting the OPA's potential as a psychophysical tool for quantifying photoallodynia. Further research is needed to assess its diagnostic utility across COP

Why do they classify it as a psychophysical tool? Wouldn’t this be a neuro-ophthalmological tool?

 

[SNT Gatchaman]

Despite its clinical relevance, standardized methods for quantifying photoallodynia remain limited. Traditional assessment relies on self-reported symptoms, with photoallodynia-related questions embedded in validated DE symptom questionnaires.

To address these limitations, our group developed the Ocular Photosensitivity Analyzer (OPA), a validated, automated system designed to quantify visual photosensitivity discomfort thresholds (VPDT) across a 1 to 32,000 lux range [24]. The OPA determines the VPDT using a psychophysical staircase paradigm, in which light stimulus intensity oscillates in ascending and descending steps. Participants press a button when the light becomes uncomfortable, and the VPDT is calculated by the device algorithm based on the intersection of these ascending and descending response curves. This method improves precision by estimating perceptual thresholds across multiple transitions in stimulus intensity.

It's hard to imagine there's some static threshold. I can experience light hypersensitivity some days in the later evening and I have the lights down very low and my wife has to read her iPad in dark mode/dim when next to me. At other times this symptom is not present. So it's variable across a longer timeframe.

Anyhow in comes the central sensitisation blather.

Our study is the first to implement the OPA, a standardized psychophysical tool, to quantify light-evoked discomfort in individuals with COP [chronic ocular pain], revealing that patients with COP exhibited heightened light sensitivity, evidenced by lower VPDTs and higher photoallodynia related questionnaire scores compared to controls. Furthermore, symptom reports aligned with OPA-assessed photosensitivity discomfort, with the strongest correlation noted with Q9 of the NPSI-Eye. Interestingly, when examined in conjunction with other pain conditions, COP did not remain a significant predictor of VPDT. Instead, fibromyalgia and chronic fatigue emerged as the most significant predictors, suggesting that photoallodynia presence may be more pronounced in individuals with broader nociplastic phenotypes.

the association between COP, systemic pain c tions, and heightened photosensitivity discomfort is consistent with prior evidence suggesting overlapping mechanisms involving central and peripheral sensitization.

Beyond the retina, cortical mechanisms likely play a key role in photoallodynia, as discomfort from flicker, patterns, or color often arises from higher-order visual processing. Functional MRI studies have demonstrated increased trigeminal system activation and altered thalamocortical connectivity in individuals with COP and photoallodynia, reinforcing the role of central sensitization. Structural and functional imaging studies further support neuroplasticity and altered cortical processing in photoallodynia associated with fibromyalgia, chronic fatigue, and migraine.

So I guess I need me some multidisciplinary interventions.

Together, these findings suggest that photoallodynia in chronic pain conditions arises from a combination of genetic predisposition, retinal-thalamic hypersensitivity, and central cortical dysfunction, reinforcing the need for targeted interventions addressing both peripheral and central mechanisms.