The chorioretinal damage caused by different half parameters of photodynamic therapy in rabbits

Regenerative Retinal Laser and Light Therapies (RELITE): Proposal of a New Nomenclature, Categorization, and Trial Reporting Standard

OBJECTIVES

Numerous laser and light therapies have been developed to induce regenerative processes in the choroid/retinal pigment epithelium (RPE)/photoreceptor complex, leaving the neuroretina undamaged. These therapies are applied to the macula for the treatment of various diseases, most prominently diabetic maculopathy, retinal vein occlusion, central serous chorioretinopathy, and age-related macular degeneration. However, the abundance of technologies, treatment patterns, and dosimetry protocols has made understanding these therapies and comparing different approaches increasingly complex and challenging. To address this, we propose a new nomenclature system with a clear categorization that will allow for better understanding and comparability between different laser and light modalities. We propose this nomenclature system as an open standard that may be adapted in future toward new technical developments or medical advancements.

METHODS

A systematic literature review of reported macular laser and light therapies was conducted. A categorization into a standardized system was proposed and discussed among experts and professionals in the field. This paper does not aim to assess, compare, or evaluate the efficacy of different laser or dosimetry techniques or treatment patterns.

RESULTS

The literature search yielded 194 papers describing laser techniques, 50 studies describing dosimetry, 272 studies with relevant clinical trials, and 82 reviews. Following the common therapeutic aim, we propose "regenerative retinal laser and light therapies (RELITE)" as the general header. We subdivided RELITE into four main categories that refer to the intended physical and biochemical effects of temperature increase (photothermal therapy, PTT), RPE regeneration (photomicrodisruption therapy, PMT), photochemical processes (photochemical therapy, PCT), and photobiomodulation (photobiomodulation therapy, PBT). Further, we categorized the different dosimetry approaches and treatment regimens. We propose the following nomenclature system that integrates the most important parameters to enable understanding and comparability: Pattern-Dosimetry-Exposure Time/Frequency, Duty Cycle/Irradiation Diameter/Wavelength-Subcategory-Category.

CONCLUSION

Regenerative retinal laser and light therapies are widely used for different diseases and may become valuable in the future. A precise nomenclature system and strict reporting standards are needed to allow for a better understanding, reproduceable and comparable clinical trials, and overall acceptance. We defined categories for a systematic therapeutic goal-based nomenclature to facilitate future research in this field.

Treatment outcomes of photodynamic therapy and findings predicting treatment success in pachychoroid-associated neovascularization

PURPOSE

To investigate the treatment outcomes and predictive factors affecting treatment success of half-fluence photodynamic therapy (hf-PDT) in pachychoroid-associated neovascularization (PNV).

METHODS

Twenty-four eyes of 23 PNV patients who underwent hf-PDT were included in this study. The results of optical coherence tomography (OCT) and OCT-angiography imaging were analyzed. The total choroidal area (CA), luminal area (LA), and stromal area (SA) were measured using ImageJ software. Baseline characteristics of the eyes showing complete response (group 1) and the eyes with partial response or unresponsive to hf-PDT (group 2) were compared.

RESULTS

The mean age of the patients was 54.2±9.6 years. The mean follow-up time after hf-PDT was 20.7 ± 13.6 months. Three months after hf-PDT, the subretinal fluid had completely regressed in 18 eyes (75.0%), partial resolution was observed in 3 eyes (12.5%), and 3 eyes (12.5%) were unresponsive to hf-PDT. When the baseline characteristics before hf-PDT were evaluated between the groups, the mean central choroidal thickness (411.5 ± 115.1 µm vs 284.8 ± 69.4 µm), the mean CA (1.082 ± 0.315 mm² vs 0.795 ± 0.242 mm²) and the mean LA (0.795 ± 0.234 mm² vs 0.578 ± 0.200 mm²) was significantly higher in group 1 compared to group 2 (p = 0.019, p = 0.018, p = 0.018, respectively).

CONCLUSION

Hf-PDT is an effective treatment method usually providing total resolution of subretinal fluid in PNV cases. A high baseline central choroidal thickness and large luminal area may be positive predictive factors in terms of full anatomical response to hf-PDT. It may be possible to plan a more effective treatment strategy by keeping these factors in mind.

Long-Term Outcomes of Full-Fluence and Half-Fluence Photodynamic Therapy for Chronic Central Serous Chorioretinopathy

PURPOSE

To evaluate the efficacy and safety of full-fluence photodynamic therapy (PDT) and half-fluence PDT in chronic central serous chorioretinopathy (CSC).

PROCEDURES

A retrospective review of CSC patients treated with full-fluence or half-fluence PDT for 12 months was performed. Best-corrected visual acuity (BCVA), central macular thickness (CMT), neural retinal thickness, subfoveal choroidal thickness (SFCT), resolution of subretinal fluid (SRF), and incidence of retinal pigment epithelium (RPE) atrophy at 12, 24, and 36 months were assessed.

RESULTS

Thirty-seven and 30 eyes received full-fluence and half-fluence PDT, respectively. The BCVA and CMT improved significantly in both the full-fluence and half-fluence groups at 36 months, without a significant difference between the groups. Both groups showed significant reductions in SFCT with full-fluence (416.8-316.8 µm) being better overall than half-fluence (409.7-349.1 µm, p = 0.002). All patients achieved complete resolution without recurrence after one PDT treatment per eye. A few cases of RPE atrophy occurred, which could be correlated to PDT in both groups during the follow-up.

CONCLUSION

Both treatments were effective and safe in chronic CSC, with significant improvements in anatomic and visual parameters, without recurrence of SRF.