Morphological Changes of Ciliary Body and Trabecular Meshwork

Yune Zhao

Status: Unknown

Conditions: Myopia; Glaucoma

Treatments: Drug: 0.5% pilocarpine eye drops

Study type: Interventional

Funder types: Other

Identifiers

NCT05352854

Myopia-OAG SSOCT

Details and patient eligibility

About

Glaucoma is the leading cause of irreversible blindness worldwide. Although the pathogenesis remains unclear, pathologic increase in intraocular pressure (IOP) due to blocked aqueous outflow through the trabecular-Schlemm canal is known to be an important risk factor, and reduction of IOP is the only clinically validated way to retard the progression of OAG. Ciliary muscle plays a central role in the trabecular meshwork-Schlemm canal outflow pathway. Clinical evidence suggests that ciliary muscle contraction stimulated by cholinergic receptor agonist and retraction of ciliary body position after cataract surgery can dilate the lumen of Schlemm canal and reduce IOP. Currently, Ultrasound biomicroscopy (UBM) can obtain two-dimensional images of the anterior segment using high-frequency Ultrasound transducers in medical imaging studies of the ciliary body - trabecular meshwork -Schlemm canal complex. UBM has better tissue penetration than Optical coherence tomography (OCT) and can image the ciliary body better, but it has a lower resolution (30um to 50um) and is poor at imaging tiny tissues such as trabecular meshwork and Schlemm canal. The latest swept-source OCT (SS-OCT) has faster image capture rate (1000000 A scans/SEC), stronger penetration and higher resolution (8um axial resolution and 20um transverse resolution). The structure and morphology of ciliary body-trabecular meshwork-Schlemm canal complex can be clearly photographed. The investigators intend to use CASIA2 to image the ciliary body-trabecular meshwork-Schlemm canal complex before and after administration of pilocarpine in healthy individuals and patients with glaucoma to assess the effect of pilocarpine on the anatomy of the ciliary body-trabecular meshwork-Schlemm canal complex.

Full description

Glaucoma is the leading cause of irreversible blindness worldwide. Although the pathogenesis remains unclear, pathologic increase in intraocular pressure (IOP) due to blocked aqueous outflow through the trabecular-Schlemm canal is known to be an important risk factor, and reduction of IOP is the only clinically validated way to retard the progression of OAG. Ciliary muscle plays a central role in the trabecular meshwork-Schlemm canal outflow pathway. When the ciliary muscle contraction, the elastic fiber network will pull trabecular meshwork away from Schlemm canal direction, trabecular meshwork and adjacent tissue gap increases, increasing aqueous outflow. Clinical evidence suggests that ciliary muscle contraction stimulated by cholinergic receptor agonist and retraction of ciliary body position after cataract surgery can dilate the lumen of Schlemm canal and reduce IOP. Currently, Ultrasound biomicroscopy (UBM) can obtain two-dimensional images of the anterior segment using high-frequency Ultrasound transducers in medical imaging studies of the ciliary body - trabecular meshwork -Schlemm canal complex. UBM has better tissue penetration than Optical coherence tomography (OCT) and can image the ciliary body better, but it has a lower resolution (30um to 50um) and is poor at imaging tiny tissues such as trabecular meshwork and Schlemm canal. The latest swept-source OCT (SS-OCT) has faster image capture rate (1000000 A scans/SEC), stronger penetration and higher resolution (8um axial resolution and 20um transverse resolution). The structure and morphology of ciliary body-trabecular meshwork-Schlemm canal complex can be clearly photographed. The novel anterior segment optical coherence tomography (AS-OCT) device, CASIA2 can accurately image the ciliary body-trabecular meshwork-Schlemm canal complex. The investigators intend to use CASIA2 to image the ciliary body-trabecular meshwork-Schlemm canal complex before and after administration of pilocarpine in healthy individuals and patients with glaucoma to assess the effect of pilocarpine on the anatomy of the ciliary body-trabecular meshwork-Schlemm canal complex.

Enrollment: 120 estimated patients

Sex: All

Ages: 18 to 60 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• Emmetropia/low myopia,high myopia, primary open-angle glaucoma without high myopia, and high myopia with primary open-angle glaucoma
• have a good gaze to complete the test required inspection;

Exclusion criteria

• hypersensitivity to pilocarpine
• History of eye surgery, including cataract surgery, anti-glaucoma surgery, corneal surgery, retinal surgery, and eye trauma
• history of systemic diseases that may affect the eyes (such as diabetes, hypertension, etc.)
• intraocular chronic inflammatory diseases (uveitis, etc.), retinal diseases (retinal detachment, diabetic retinopathy, retinitis pigmentosa, etc.)
• Corneal scars and severe cataracts affect OCT imaging
• Eye diseases (angle-closure glaucoma, abnormal anterior segment development, neovascularization, etc.) that can affect trabecular meshwork and Schlemm canal structure.

Trial design

Primary purpose: Other

Allocation: Non-Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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120 participants in 4 patient groups

Health control

Experimental group

Description:

emmetropia/low myopia (equivalent spherical lens \> -3.00d, astigmatism ≤ 1.5d), best corrected visual acuity ≥1.0

Treatment:

Drug: 0.5% pilocarpine eye drops

High myopia

Experimental group

Description:

Equivalent spherical lens ≤-6.00D or axial length ≥26.5mm

Treatment:

Drug: 0.5% pilocarpine eye drops

Primary open angle glaucoma

Experimental group

Description:

emmetropia/low myopia (equivalent spherical lens \> -3.00d, astigmatism ≤ 1.5d), diagnosed as POAG

Treatment:

Drug: 0.5% pilocarpine eye drops

HM-POAG

Experimental group

Description:

Equivalent spherical lens ≤-6.00D or axial length ≥26.5mm，diagnosed as POAG

Treatment:

Drug: 0.5% pilocarpine eye drops