(1) Background: The purpose of this study is to investigate the effects of topical steroids on conjunctiva in patients undergoing filtration surgery (FS) for glaucoma by using confocal microscopy (CM); (2) Methods: One hundred and four glaucomatous patients were randomized to fluorometholone or lubricants four weeks before FS. CM was performed before treatments and pre-operatively. Dendritic and goblet cell densities (DCD, GCD), stromal meshwork reflectivity (SMR), vascular tortuosity (VT), and intra-ocular pressure (IOP) were the main outcomes. By evaluating treatments and outcomes (12-month success/failure) as categorical variables, patients were grouped into Group 1, 2, 3, or 4 (success/failure with fluorometholone, or lubricants); (3) Results: Twelve-month IOP was reduced in Groups 1 and 3 (p < 0.001). After treatments, DCD and SMR were reduced in Groups 1 and 2 (p < 0.01), and 1 and 3 (p < 0.05), respectively. Pre-operative DCD was lower in the steroid compared to lubricant group (p < 0.001), whereas SMR was lower in successful (1 and 3) compared to failed groups (2 and 4) (p = 0.004). There were no significant differences between the fluorometholone and lubricant groups for success percentages. The number of bleb management procedures and IOP lowering medications were lower in Group 1 compared to Groups 2−4 (p < 0.05); (4) Conclusions: Topical steroids mitigate conjunctival inflammation and lower the stromal density in patients undergoing FS. These modifications lead to less intensive post-operative management.
Keywords: conjunctiva; glaucoma filtration surgery; in vivo confocal microscopy; ocular surface preparation; steroids; surgery outcome.