Studying the Effect of Iris Mechanics on the Pupillary Light Reflex Using Brimonidine-Induced Anisocoria

Chen, Yanjun; Kardon, Randy H.

doi:10.1167/iovs.12-10916

Cited by 15 publications

(13 citation statements)

References 46 publications

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“…The effect was similar to that reported in other studies [29, 30]. On the other hand, other studies reported that the antimydriatic effect of brimonidine was pronounced under both light and dark luminance conditions [31–34]. Therefore, the application of brimonidine 20 min before activities in dimly lit areas or at night may be recommended for photic phenomena following laser refractive surgery [35].…”

Section: Discussionsupporting

confidence: 86%

Clinical outcomes of combined versus separate carbachol and brimonidine drops in correcting presbyopia

Abdelkader

Kaufman

2016

Eye and Vis

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BackgroundTo test and compare in a masked fashion the efficacy of using a parasympathomimetic drug (3% carbachol) and an alpha-2 agonist (0.2% brimonidine) in both combined and separate forms to create optically beneficial miosis to pharmacologically improve vision in presbyopia.MethodsA prospective, double-masked, randomized, controlled clinical trial was conducted. Ten naturally emmetropic and presbyopic subjects between 42 and 58 years old with uncorrected distance visual acuity of at least 20/20 in both eyes without additional ocular pathology were eligible for inclusion. All subjects received 3% carbachol and 0.2% brimonidine in both combined and separate forms, 3% carbachol alone and 0.2% brimonidine (control) alone in their non-dominant eye in a crossover manner with one week washout between tests. The subjects’ pupil sizes and both near and distance visual acuities will be evaluated pre- and post-treatment at 1, 2, 4, and 8 h, by a masked examiner at the same room illumination.ResultsStatistically significant improvement in mean near visual acuity (NVA) was achieved in all subjects who received combined 3% carbachol and 0.2% brimonidine in the same formula compared with those who received separate forms or carbachol alone or brimonidine alone (P < 0.0001).ConclusionBased on the data, the combined solution demonstrated greater efficacy than the other solutions that were tested. Improving the depth of focus by making the pupil small caused statistically significant improvement in near visual acuity, with no change in binocular distance vision.Trial registration ACTRN12616001565437. Registered 11 November 2016.

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Section: Discussionsupporting

confidence: 86%

Clinical outcomes of combined versus separate carbachol and brimonidine drops in correcting presbyopia

Abdelkader

Kaufman

2016

Eye and Vis

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“…The effect of brimonidine ophthalmic solution (0.1-0.2%) on the melanopsin-mediated PIPR Late remains uninvestigated, while other topical antiglaucomatous drugs such as dorzolamide, latanoprost and timolol do not affect the melanopsin-mediated PIPR Late (Ba-Ali et al 2015). Nonetheless, despite anisocoria, Chen & Kardon (2013). found no difference in the transient PLR between the brimonidine-treated eyes compared to the fellow untreated eyes when stimulated with red light.…”

Section: Discussionmentioning

confidence: 99%

“…). Nonetheless, despite anisocoria, Chen & Kardon (). found no difference in the transient PLR between the brimonidine‐treated eyes compared to the fellow untreated eyes when stimulated with red light.…”

Section: Discussionmentioning

confidence: 99%

Melanopsin‐mediated pupillary light reflex and sleep quality in patients with normal tension glaucoma

Ahmadi

Lund‐Andersen

Kolko

et al. 2019

Acta Ophthalmologica

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Purpose: The intrinsically photosensitive retinal ganglion cells (ipRGCs) and sleep quality are impaired in patients with primary open-angle glaucoma (POAG). In this study, we investigated whether ipRGCs and sleep quality were also impaired in patients with normal tension glaucoma (NTG). Methods: We performed pupillometry and sleep quality assessment in 15 patients with NTG and 17 healthy age-matched controls. Pupillometry protocol consisted of monocular stimulation with high illuminance (100 lux) red (633 nm, 300 cd/m 2 or 15.23 log quanta/cm 2 /s) and blue light (463 nm, 332 cd/m 2 or 15.27 log quanta/cm 2 /s) and binocular pupil measurements. Prior to light stimulation, patients were dark-adapted for 5 min. The late postillumination pupillary response (PIPR Late ) to blue light was used as marker of ipRGC activity. Sleep quality was assessed by Pittsburgh Sleep Quality Index (PSQI) questionnaire. Results: The PIPR Late to blue light was significantly reduced in patients with NTG compared to healthy subjects (p < 0.001), indicating impairment of the melanopsin-mediated pupillary pathway. There was no significant difference in the response elicited by red light (p = 0.6). Baseline pupil diameter and pupillary constriction amplitude to both red and blue light were reduced in patients with NTG (p < 0.05). The global score in PSQI was not significantly different between healthy controls and patients with NTG, indicating normal sleep quality (p = 0.6). Furthermore, we found no correlation between sleep parameters and pupillary light reflex parameters. Conclusion: Patients with NTG exhibited reduced ipRGC activity compared to healthy subjects, while no differences were observed in sleep quality.

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“…Such variability could also be due to mechanical effects of small pupil size on iris movement. 63 We used a closed-loop paradigm, such that PLR was measured in the same eye that received the light stimulation; hence, retinal illumination was affected by baseline pupil size. To minimize the influence of pupil size, an open-loop paradigm could be used in which one pupil is dilated pharmacologically and stimulated with light but recordings are taken from the undilated contralateral eye.…”

Section: Discussionmentioning

confidence: 99%

Assessment of Rod, Cone, and Intrinsically Photosensitive Retinal Ganglion Cell Contributions to the Canine Chromatic Pupillary Response

Yeh

Koehl

Harman

et al. 2017

Invest. Ophthalmol. Vis. Sci.

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PurposeThe purpose of this study was to evaluate a chromatic pupillometry protocol for specific functional assessment of rods, cones, and intrinsically photosensitive retinal ganglion cells (ipRGCs) in dogs.MethodsChromatic pupillometry was tested and compared in 37 dogs in different stages of primary loss of rod, cone, and combined rod/cone and optic nerve function, and in 5 wild-type (WT) dogs. Eyes were stimulated with 1-s flashes of dim (1 cd/m2) and bright (400 cd/m2) blue light (for scotopic conditions) or bright red (400 cd/m2) light with 25-cd/m2 blue background (for photopic conditions). Canine retinal melanopsin/Opn4 was cloned, and its expression was evaluated using real-time quantitative reverse transcription-PCR and immunohistochemistry.ResultsMean ± SD percentage of pupil constriction amplitudes induced by scotopic dim blue (scDB), scotopic bright blue (scBB), and photopic bright red (phBR) lights in WT dogs were 21.3% ± 10.6%, 50.0% ± 17.5%, and 19.4% ± 7.4%, respectively. Melanopsin-mediated responses to scBB persisted for several minutes (7.7 ± 4.6 min) after stimulus offset. In dogs with inherited retinal degeneration, loss of rod function resulted in absent scDB responses, followed by decreased phBR responses with disease progression and loss of cone function. Primary loss of cone function abolished phBR responses but preserved those responses to blue light (scDB and scBB). Although melanopsin/Opn4 expression was diminished with retinal degeneration, melanopsin-expressing ipRGCs were identified for the first time in both WT and degenerated canine retinas.ConclusionsPupil responses elicited by light stimuli of different colors and intensities allowed differential functional assessment of canine rods, cones, and ipRGCs. Chromatic pupillometry offers an effective tool for diagnosing retinal and optic nerve diseases.

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Studying the Effect of Iris Mechanics on the Pupillary Light Reflex Using Brimonidine-Induced Anisocoria

Cited by 15 publications

References 46 publications

Clinical outcomes of combined versus separate carbachol and brimonidine drops in correcting presbyopia

Clinical outcomes of combined versus separate carbachol and brimonidine drops in correcting presbyopia

Melanopsin‐mediated pupillary light reflex and sleep quality in patients with normal tension glaucoma

Assessment of Rod, Cone, and Intrinsically Photosensitive Retinal Ganglion Cell Contributions to the Canine Chromatic Pupillary Response

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