Optical Coherence Tomography Angiography and Glaucoma: A Clinical Case Study

Overview

This report discusses a glaucoma patient with a history of LASIK, highlighting the use of optical coherence tomography angiography (OCT-A) to detect focal ganglion cell complex and retinal nerve fiber layer thinning alongside peripapillary perfusion loss. Visual field testing corroborated these findings, and ongoing monitoring shows stable structural and perfusion parameters, though concerns about long-term prognosis remain.

Background

Glaucoma is a complex optic neuropathy characterized by progressive retinal ganglion cell loss and visual field defects. Intraocular pressure (IOP) is a key modifiable risk factor, but its measurement can be complicated in patients with prior refractive surgery due to altered corneal properties. Optical coherence tomography angiography (OCT-A) provides noninvasive imaging of retinal and optic nerve microvasculature, offering insights into vascular contributions to glaucoma pathophysiology. Combining structural and functional assessments aids in comprehensive glaucoma management.

Data Highlights

The patient had central corneal thickness measurements of 474 µm and 476 µm in the right and left eyes, respectively. OCT-A revealed focal inferior ganglion cell complex (GCC) and retinal nerve fiber layer (RNFL) thinning in the right eye and less focal thinning in the left eye. Moderate peripapillary perfusion loss corresponded to RNFL thinning. Visual field testing showed defects consistent with structural and perfusion findings. Follow-up OCT-A and visual fields over multiple years demonstrated stable structure and perfusion loss with stable visual fields.

Key Findings

• Post-LASIK corneal thickness was thin (474 µm and 476 µm), necessitating cautious interpretation of IOP measurements.
• OCT-A detected focal inferior GCC and RNFL thinning correlating with moderate peripapillary perfusion loss in the right eye.
• Visual field testing confirmed corresponding functional defects matching structural and vascular changes.
• Longitudinal OCT-A and visual field assessments over several years showed stable structural and perfusion parameters with no progression.
• Significant perfusion dropout on OCT-A may indicate higher risk of glaucoma progression, especially in low-tension glaucoma patients with vascular issues.

Clinical Implications

OCT-A is a valuable tool for detecting microvascular changes in glaucoma patients, particularly those with complex histories such as prior refractive surgery. Integrating OCT-A findings with structural and functional assessments enhances risk stratification and monitoring. Regular follow-up with OCT-A and visual fields every six months can help detect progression early and guide management decisions.

Conclusion

This case illustrates the utility of OCT-A in correlating vascular, structural, and functional changes in glaucoma, emphasizing the importance of comprehensive multimodal monitoring. Continued research is needed to clarify the role of perfusion loss in glaucoma progression and to optimize management strategies.

References

1. Warren, J. OD -- Optical Coherence Tomography Angiography and Glaucoma