Aqueous Humor Hints at Graft Survival in Prior Tube or Trab Eyes

The aqueous humor (AqH) of normal eyes has a total protein level around 0.35mg/mL, but that can increase when the blood-aqueous barrier is disrupted, such as in cases of uveitis, after intraocular surgery or with iris damage. The above cases from the study show (A) a patient with preoperative AqH total protein level of 4.649mg/mL whose graft failed at just three months (right photo) and (B) a patiently with AqH of 0.90mg/mL whose cornea stayed transparent more than nine years (right photo). Photo: Kaneko S, et al. Ophthalmology Science 2026. Click image to enlarge. Glaucoma filtering surgery is a well-established risk factor for graft failure after endothelial keratoplasty, but survival rates reported in the literature aren’t 0% across the board. Researchers in Japan hypothesized that the aqueous humor microenvironment may contribute to these variable graft survival rates. Their findings on DSAEK outcomes in eyes with surgically treated glaucoma were recounted recently in Ophthalmology Science, and protein levels seem to play an important role.The case series included 181 DSAEK patients divided into three groups: no glaucoma (132 eyes); medically treated glaucoma (17 eyes) and surgically treated glaucoma (32 eyes). The researchers compared endothelial cell density and graft survival rate among the three groups and within the surgically treated glaucoma group, which was further divided by aqueous humor protein levels; samples were collected at the beginning of each surgery.After DSAEK, all groups had significant BCVA improvements. However, the researchers observed significantly lower postoperative endothelial cell density in surgically treated glaucoma eyes vs. eyes without glaucoma at all timepoints up to six years. Eyes with prior glaucoma surgery also had significantly lower graft survival, with trabeculectomy and iris damage severity as independent risk factors for graft failure.In terms of aqueous humor protein in the surgically treated glaucoma group, high total protein levels were linked to poor graft survival. The six-year graft survival was 100% in the low-protein group (<0.7mg/mL, n=4); 23% in the medium-protein group (0.7mg/mL to 1.6mg/mL, n=17); and 0% in the high-protein group (>1.6mg/mL, n=10).Since graft survival differed by protein level in eyes with and without prior glaucoma surgery, the researchers believe it’s likely that “elevated aqueous humor total protein levels reflect a pathological aqueous humor microenvironment that adversely affects graft survival. However, in eyes with surgically treated glaucoma, graft survival was poorer, potentially reflecting a more severely altered aqueous milieu related to chronic disruption of the blood aqueous barrier, the presence of filtering blebs or persistent intraocular inflammation. Therefore, preoperative aqueous humor total protein level may serve as a predictive biomarker for the graft survival in patients with surgically treated glaucoma.” They identified 0.7mg/mL and 1.6mg/mL as cut-off levels for reference.Click here for the source. Kaneko S, Yagi-Yaguchi Y, Shijo T, et al. Aqueous humor total protein levels predict 6-year graft survival after endothelial keratoplasty in surgically treated glaucoma eyes. Ophthalmology Science 2026. [Epub ahead of print].  This article was developed by the editorial staff in conjunction with experts in the field. In the process, AI may have been among the editorial tools used to meet the goals of human editors, who approved all content.