Confocal Microscopy and Anterior Segment Optical Coherence Tomography Imaging of the Ocular Surface and Bleb Morphology in Medically and Surgically Treated Glaucoma Patients: A Review

Abstract

Glaucoma patients often suffer from ocular surface disease (OSD) caused by the chronic administration of topical anti-glaucoma medications, especially in cases of long-term therapy with preserved or multiple drugs. Additionally, glaucoma surgery may determine ocular surface changes related to the formation and location of the filtering bleb, the application of anti-mitotic agents, and the post-operative wound-healing processes within the conjunctiva. Recently, several studies have evaluated the role of advanced diagnostic imaging technologies such as in vivo confocal microscopy (IVCM) and anterior segment-optical coherence tomography (AS-OCT) in detecting microscopic and macroscopic features of glaucoma therapy-related OSD. Their clinical applications are still being explored, with recent particular attention paid to analyzing the effects of new drug formulations and of minimally invasive surgical procedures on the ocular surface status. In this review, we summarize the current knowledge about the main changes of the ocular surface identified at IVCM and AS-OCT in glaucoma patients under medical therapy, or after surgical treatment.

Nanotechnology-based ocular drug delivery systems: recent advances and future prospects

“…For example, the content of drugs can be detected in tears and aqueous humor through ELISA (Enzyme-linked Immunosorbent Assay) or HPLC (High Performance Liquid Chromatography) in vitro [ 329 , 330 ]. Alternatively, fluorescence-labeled drugs could be used and then detected by confocal microscopy in vivo [ 331 ]. Besides, the results can be analyzed by some pharmacokinetic parameters, such as the maximum drug concentration (Cmax), the time required to reach Cmax (Tmax), and the area under the concentration–time curve (AUC0-t) [ 332 ].…”

Glaucoma and Dry Eye Disease: Opportunity to Assess and Treat

“… 60 , 61 Trabeculectomy is a filtering surgery that involves the creation of a drainage path from the anterior chamber to the subconjunctival space. 62 Following trabeculectomy, Zhong et al found reductions in tear breakup time and increases in corneal staining, which did not fully recover to baseline at 3 months postsurgery. 61 Ocular surface signs following trabeculectomy may be related to the presence of the filtering bleb.…”

Commentary: Evaluating ocular surface disease in glaucoma

“…These changes are particularly pronounced with preserved medications and multi-drug therapy. [ 5 6 ] The development of OSD can significantly affect the quality of life of these patients. More importantly, it can cause serious problems with medication compliance, compromising the target IOP and contributing to disease progression in these patients.…”

“…[ 7 ] However, improvements in the ocular surface have been documented in glaucoma patients following surgery, particularly in minimally invasive glaucoma surgery (MIGS) and non-penetrating deep sclerectomy (NPDS), as demonstrated in this study. [ 5 8 ] This is most likely due to the cessation of toxic effects of AGMs and smoother bleb characteristics seen following these surgeries. [ 5 ] The ocular surface may be relatively spared from the effects of severe inflammation due to extensive conjunctival handling in conventional trabeculectomy and glaucoma drainage devices (GDDs).…”

“…[ 5 8 ] This is most likely due to the cessation of toxic effects of AGMs and smoother bleb characteristics seen following these surgeries. [ 5 ] The ocular surface may be relatively spared from the effects of severe inflammation due to extensive conjunctival handling in conventional trabeculectomy and glaucoma drainage devices (GDDs). The choice of surgery is complex and dictated by several factors such as type and severity of glaucoma, baseline IOP, target IOP, any previous surgery, and the cost of the proposed procedure.…”