Abstract
Glaucoma causes irreversible neuropathy, which, untreated, may lead to blindness. In this case–control study, we measured two-photon infrared (IR) light sensitivity in glaucomatous eyes to propose a new method to quantify the visual loss. In total, 64 patients were recruited with an equal distribution between glaucoma and control groups. Retinal sensitivity to IR light was assessed using a two-photon excitation device. A fundus-driven microperimeter was used to measure retinal sensitivity to visible light. The retinal nerve fiber layer (RNFL) thickness was quantified automatically with optical coherence tomography. The IR sensitivity of glaucoma and control eyes differed significantly (P = .003): 9.8 (6.5 to 13.1) dB vs. 10.9 (8.2 to 13.0) dB. Although in the visible-light microperimetry, retinal sensitivity was decreased in glaucoma (17.0, range: 6.9 to 20.0 dB) compared to the controls (17.7, range: 11.6 to 20.0 dB), this difference did not reach the significance level. A significant thinning of the RNFL in the glaucoma group was observed (P < .001). IR sensitivity significantly correlated with the RNFL in three of the four assessed quadrants instead of only one in visible-light microperimetry. Although further research is needed, this proof-of-concept study suggests that IR-light sensitivity can be used to support the detection of glaucomatous neuropathy.
Highlights
Glaucoma causes irreversible neuropathy, which, untreated, may lead to blindness
We demonstrated that glaucomatous eyes have significantly decreased sensitivity to IR light compared to eyes in an age-matched control group
The application of visible-light microperimetry to detect glaucomatous retinal sensitivity was studied by Oztürk et al in patients with open-angle glaucoma and their results were compared with healthy c ontrols[5]
Summary
Glaucoma causes irreversible neuropathy, which, untreated, may lead to blindness In this case– control study, we measured two-photon infrared (IR) light sensitivity in glaucomatous eyes to propose a new method to quantify the visual loss. Fundus-driven perimetry (microperimetry) applies this principle and combines the assessment of retinal sensitivity, considering the patient’s fixation behavior (real-time fundus-tracking) during the examination, and obtaining simultaneously retinal images[5,6,7,9,10] This approach can quantify how structural changes at the retina translate into a functional effect[6]. Approach demonstrated a higher precision than visible-light technology in testing retinal function and resistance to lenticular o pacification[16,21] This novel approach has recently been applied in the studies of IR vision in the healthy population and patients with diabetic retinopathy[17,18]. The impact of glaucoma on IR-light sensitivity has not yet been evaluated
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