Changes in Choroidal Thickness Following Panretinal Photocoagulation: A Retrospective Study from Al Qassim, Saudi Arabia

Panretinal photocoagulation (PRP) remains a cornerstone treatment for proliferative diabetic retinopathy, yet its effects on the choroid—the vascular layer beneath the retina—are not fully understood. A recent retrospective study conducted in the Al Qassim region of Saudi Arabia sought to evaluate changes in choroidal thickness before and six months after PRP in patients with diabetic retinopathy. The findings contribute to growing evidence that PRP influences not only retinal structure but also choroidal morphology, with implications for long-term ocular health in diabetic patients.

Study Design and Patient Population

The study, published in SCIRP Open Access, analyzed data from patients who underwent PRP for diabetic retinopathy at a clinical center in Al Qassim, Saudi Arabia. Choroidal thickness was measured using enhanced depth imaging optical coherence tomography (EDI-OCT) at baseline and six months post-treatment. The researchers focused on subfoveal choroidal thickness (SFChT) as a key parameter, comparing pre- and post-PRP values to assess significant changes.

While the exact number of participants and specific demographic details were not disclosed in the source material, the study design aligns with standard retrospective analyses aimed at evaluating structural ocular changes following laser therapy. The use of EDI-OCT ensures reliable, reproducible measurements of choroidal thickness, which is critical for detecting subtle but clinically meaningful alterations.

Key Findings on Choroidal Thickness Changes

Six months after PRP, the study observed a statistically significant change in choroidal thickness. Although the direction of change (increase or decrease) was not explicitly stated in the provided source summary, similar investigations in the literature consistently report a reduction in subfoveal choroidal thickness following PRP. For instance, a 2020 study published in BMC Ophthalmology found that both conventional and pattern scanning laser PRP led to a significant decrease in SFChT at 1, 3, 6, and 12 months post-treatment, with the reduction occurring sooner in the conventional laser group.

Additional research using optical coherence tomography angiography (OCT-A) has corroborated these findings, demonstrating that PRP affects not only retinal microvasculature and blood flow but also choroidal thickness and vascularity. These changes are thought to stem from the inflammatory and ischemic effects of widespread laser photocoagulation, which may trigger remodeling in both retinal and choroidal compartments.

Clinical Implications

The observed alterations in choroidal thickness following PRP underscore the importance of monitoring posterior segment changes beyond the retina in diabetic patients undergoing laser therapy. Since the choroid plays a vital role in supplying oxygen and nutrients to the outer retina, long-term thinning could potentially impact retinal homeostasis, particularly in eyes already vulnerable due to diabetic microvascular damage.

Clinicians may consider incorporating choroidal thickness assessment into routine follow-up protocols for patients receiving PRP, especially those with advanced diabetic retinopathy or additional risk factors for choroidal pathology. Further longitudinal studies are needed to determine whether PRP-induced choroidal changes are transient or progressive and how they correlate with functional visual outcomes over time.

Conclusion

This retrospective study from Al Qassim adds valuable regional data to the global understanding of how panretinal photocoagulation affects ocular structure in diabetic retinopathy. By demonstrating measurable changes in choroidal thickness six months after treatment, it highlights the necessitate for a holistic view of posterior segment health in diabetes management. As imaging technologies like EDI-OCT and OCT-A become more accessible, routine choroidal monitoring may emerge as a key component of personalized care for patients undergoing retinal laser therapy.

Future research should focus on larger, multicenter cohorts with longer follow-up periods to clarify the temporal dynamics of choroidal response to PRP and its relationship to visual prognosis. Such insights will help refine treatment strategies and optimize long-term retinal preservation in diabetic patients.