A study recently published in American Journal of Ophthalmology investigated connections between anterior chamber angle (ACA) status and limbal epithelial basal cells (LEBCs) in primary angle-closure glaucoma (PACG).
Give me some background first.
When limbal epithelial stem cells (LESCs) are impacted due to injury, infection, or disease, limbal stem cell deficiency (LSCD) occurs.
Previous research has found that “the density of basal cells in the central cornea and limbus of LSCD patients decreased.”
Tell me more.
Long-term topical treatment for glaucoma can cause inflammation that impacts the number and function of LESCs, ultimately leading to LSCD. In fact, studies have suggested that inflammation can also lead to trabecular meshwork dysfunction.
With this in mind, researchers sought to investigate the relationship between limbal epithelial basal cell (LEBC) changes and ACA status (open angle or closed angle) in patients with PACG.
Now, talk about the study.
This cross-sectional observational study included 54 eyes from 29 subjects with PACG, of which 12 were male and 17 were female. In addition, 54 eyes (of healthy subjects) were included for control and were matched for age and gender.
What were the outcome measures and methods?
Ultrasound biomicroscopy (UBM) images were taken to measure ACA status in the participants, while in vivo confocal microscopy (IVCM) was utilized to capture images of LEBCs in the patients’ eyes in multiple directions.
Anything else?
The 54 PACG eyes were classified into three different stages as follows:
- 16 eyes in the early stage
- 23 eyes in the moderate stage
- 15 eyes in the advanced stage
Now the findings.
No statistically significant differences in terms of age and gender were found between the control and PACG groups.
These findings aligned with previous research that was also IVCM-based, where 43 eyes of LSCD-diagnosed patients were studied.
Start with LEBC density.
LEBC density levels in the control group were found in the following order, from highest to lowest:
- Superior limbus
- Temporal limbus
- Inferior limbus
- Nasal limbus
In comparison, the PACG eye’s density levels from highest to lowest were:
- Inferior limbus
- Superior limbus
- Temporal limbus
- Nasal limbus
Overall, the average density of LEBCs was lower in four limbal regions in PACG eyes compared to control.
Go on…
The density of LEBCs corresponding to closed angle status were lower at all stages of PACG than in the control group (P<0.05).
In addition, the density of LEBCs in PACG was less in closed angle than open angle status in all stages (early and moderate stages: P<0.05; advanced stage: P>0.05).
Expert opinion?
The study authors stated that their findings, “confirm that angle closure not only disrupts the smooth circulation of aqueous humor, but also leads to a reduction in the density of LEBCs, ultimately triggering LSCD.”
They referred to the analysis revealing a decline in LEBC density as PACG progresses.
Take home.
Although larger scale research is necessary to examine all variations, significant correlation was found between ACA status, LEBC density and the advancement of PACG in this study.
The study authors concluded, that “These findings suggest that maintaining vigilance for limbal stem cell deficiency is crucial in patients with advanced primary angle-closure glaucoma and multi-directional angle closure.”