Optic Nerve Head Changes After Intraocular Pressure-Lowering Glaucoma Surgeries Using Optical Coherence Tomography.

Area of Science:

• Ophthalmology
• Medical Imaging
• Glaucoma Research

Background:

• Glaucoma is a progressive optic neuropathy often managed with intraocular pressure (IOP)-lowering surgeries.
• Monitoring optic nerve head (ONH) structural changes is crucial for glaucoma management.
• Swept-source optical coherence tomography (SS-OCT) offers advanced imaging capabilities for the ONH.

Purpose of the Study:

• To evaluate structural changes in the optic nerve head (ONH) using SS-OCT following IOP-lowering glaucoma surgeries.
• To assess the utility of specific ONH parameters, including the hypotenuse of the ONH cup (HOC), in detecting short-term postoperative changes.

Main Methods:

• Prospective study including 15 eyes of patients with progressing glaucoma undergoing IOP-lowering procedures.
• SS-OCT imaging and visual field tests were performed preoperatively and up to 30-90 days postoperatively.
• Key parameters measured included circumpapillary retinal nerve fiber layer, visual field mean deviation, IOP, ONH cup dimensions (length, depth, HOC), and Bruch's membrane opening (BMO)-to-BMO diameter.

Main Results:

• A significant decrease in mean IOP was observed postoperatively (from 20.5 mmHg to 11 mmHg at 7 days).
• The hypotenuse of the ONH cup (HOC), ONH cup depth and length, and BMO-to-BMO diameter all significantly decreased after surgery.
• Mean HOC decreased significantly, indicating structural alterations in the optic nerve head post-IOP lowering procedures.

Conclusions:

• The hypotenuse of the ONH cup (HOC), as measured by SS-OCT, significantly decreased after IOP-lowering glaucoma surgeries.
• HOC is a valuable parameter for assessing short-term structural changes in the optic nerve head in glaucoma patients postoperatively.