The Shape of Posterior Sclera as a Biometric Signature in Open-angle Glaucoma: An Intereye Comparison Study

Impact of Cataract Surgery on IOP and Ocular Structures in Normotensive Patients and Primary and Exfoliation Open-Angle Glaucoma Patients

Purpose

The aim of this study was to evaluate and compare the changes in Intraocular Pressure (IOP) and other ocular parameters: the Anterior Chamber Angle (ACA), Anterior Chamber Volume (ACV), and Anterior Chamber Depth (ACD) during phacoemulsification surgery in Greek patients with normotensive eyes and those with well-controlled Open-Angle Glaucoma (OAG). Additionally, parameters such as the Corneal Thickness (CCT), Axial Length (AL), Central Macular Thickness (CMT), and Retinal Nerve Fibre Layer (RNFL) were also examined.

Patients and Methods

This was a prospective observational case-control study that included 50 phakic eyes, 25 normotensive (Group 1), and 25 with OAG: 15 Primary Open-Angle Glaucoma (POAG) and 10 Exfoliation Glaucoma (EXG) (Group 2). Ophthalmic assessment included IOP measurements, ocular biometry, and anterior and posterior segment optical coherence tomography evaluation of the aforementioned ocular parameters, prior and 6 months after phacoemulsification surgery.

Results

At the 6 months post-operative review, a greater IOP reduction was recorded in eyes with OAG, in comparison to normotensive ones (5.3mmHg and 1.6 mmHg respectively). In addition, a significant but similar increase was recorded in the values of the ACA, ACV, and ACD of both groups between the pre- and the post-op period. Furthermore, the CCT and AL values remained unaltered. Finally, there was a non-statistically significant change in the mean CMT and the mean average RNFL of both groups.

Conclusion

Eyes with OAG tend to undergo a greater reduction in IOP post-phacoemulsification surgery, in comparison to normotensive eyes. This reduction may not be solely attributed to ocular anatomical changes after phacoemulsification surgery but may also be due to the remodeling of the trabecular meshwork and the ciliary body. This may be especially true in the case of OAG eyes, which already start off with a compromised trabecular endothelium prior to surgery.

Central retinal vascular trunk deviation in unilateral normal-tension glaucoma

Purpose

To investigate whether the position of the central retinal vascular trunk (CRVT), as a surrogate of lamina cribrosa (LC) offset, was associated with the presence of glaucoma in normal-tension glaucoma (NTG) patients.

Methods

The position of the CRVT was measured as the deviation from the center of the Bruch’s membrane opening (BMO), as delineated by spectral-domain optical coherence tomography imaging. The offset index was calculated as the distance of the CRVT from the BMO center relative to that of the BMO margin. The angular deviation of CRVT was measured with the horizontal nasal midline as 0° and the superior location as a positive value. The offset index and angular deviation were compared between glaucoma and fellow control eyes within individuals.

Results

NTG eyes had higher baseline intraocular pressure (P = 0.001), a larger β-zone parapapillary atrophy area (P = 0.013), and a larger offset index (P<0.001). In a generalized linear mixed-effects model, larger offset index was the only risk factor of NTG diagnosis (OR = 31.625, P<0.001). A generalized estimating equation regression model revealed that the offset index was larger in the NTG eyes than in the control eyes for all ranges of axial length, while it was the smallest for the axial length of 23.4 mm (all P<0.001).

Conclusions

The offset index was larger in the unilateral NTG eyes, which fact is suggestive of the potential role of LC/BMO offset as a loco-regional susceptibility factor.

Changes in ocular morphology after cataract surgery in open angle glaucoma patients

The purpose of this study was to evaluate intraocular pressure (IOP) pre- and postoperatively, together with anterior chamber angle (ACA) parameters and biometrical results in cataract patients with or without open angle glaucoma (OAG). The prospective observational case-control study included 15 eyes with cataract and OAG in the glaucoma group and 25 eyes with only cataract in control group. Examination included full ophthalmic evaluation, IOP, ocular biometry and anterior segment optical coherence tomography measuring ACA pre- and 6 months postoperatively. OAG patients had a larger absolute IOP reduction compared to control group. Anterior chamber depth (ACD) and ACA width significantly increased in both groups. The OAG group had a tendency of narrower ACA preoperatively, but overall ACA parameters did not differ in either group pre- and postoperatively. The ACD change after surgery correlated with ACA parameters in the control group, but not in OAG group. Axial length was shorter postoperatively in the control group, but remained similar in the OAG group. Absolute IOP reduction was more pronounced in cataract patients with OAG than in cataract patients without glaucoma. ACD and ACA postoperatively increased in both groups and AL shortening was observed in non-OAG in cataract group.