Long-term outcomes of drusenoid pigment epithelium detachment in intermediate AMD treated with 577 nm subthreshold micropulse laser: a preliminary clinical study

Abstract

Aim: To evaluate the long-term anatomical and visual outcomes of drusenoid pigment epithelial detachment (D-PED) in intermediate age-related macular degeneration (AMD) eyes treated with 577 nm yellow subthreshold micropulse laser (SML).

Methods: In this retrospective study, 21 eyes of 16 patients with D-PED in intermediate AMD were consecutively included and assessed. All the eyes were treated with 577 nm SML in several sessions according to D-PED growth status. The logarithm of the minimum angle of resolution (logMAR) best-corrected visual acuity (BCVA) were assessed at the initial visit and after treatment. Spectral-domain optical coherence tomography (SD-OCT) was performed to evaluate the D-PED lifecycle by volumetric calculations. Regression analysis was used to determine the breakpoint, growth, and collapse rate of the D-PED lesions. The progression to advanced AMD was also documented.

Results: All the eyes were treated with SML for 2.9±1.0 sessions. The mean follow-up period was 25.3±12.6mo. The BCVA was stable from the baseline to final visit. All the eyes were categorized into two groups according to the anatomical changes of the D-PED lesion: the collapse group (n=6, 28.6%) and non-collapse group (n=15, 71.4%). The change in logMAR BCVA did not differ significantly between the collapse group 0.00 (-0.31, 0.85) and non-collapse group 0.00 (0.00, 0.00; P=1). Regression analysis showed that the growth rate was significantly higher in the collapse group (0.090±0.095 mm³/mo) than in the non-collapse group (0.025±0.035 mm³/mo; P<0.001). One eye (4.8%) developed macular neovascularization at 11mo after SML treatment in the non-collapse group. Three eyes (14.3%) developed geographic atrophy (GA) in the collapse group.

Conclusion: Compared to the natural course of D-PED reported by previous studies, our results preliminarily show that SML can alleviate visual loss and possibility of progression to advanced AMD in eyes with D-PED in intermediate AMD. A controlled clinical trial needs to further verify the benefit of the intervention.

Keywords: age-related macular degeneration; drusenoid pigment detachment; optical coherence tomography; retinal pigment epithelium; subthreshold micropulse laser.

Figure 1. Spectral-domain optical coherence tomography of typical drusenoid pigment detachment (D-PED) eye

A: Fundus photography shows a large D-PED in the eye; B: Red-free photography of D-PED; C: B-scan of D-PED; D: Drusen analysis report by Topcon IMAGEnet 2000 shows the 3D image of D-PED and drusen area and volume.

Figure 2. D-PED volumetric changes after treated with 577 nm subthreshold micropulse laser in the collapse group

A: Illustrative plots of the D-PED volume of a 68-year-old patient. Nonlinear regression analysis determined the breakpoint at 21mo where the D-PED volumetric slope changed significantly between periods of growth and collapse. The growth rate was 0.013 mm³/mo whereas the collapse rate was 0.076 mm³/mo. B: SD-OCT images showed the change of D-PED lesion against time. The eye received 3 times SML treatment at baseline, 5, and 13mo separately.

Figure 3. D-PED volumetric changes after treated with 577nm subthreshold micropulse laser in the non-collapse group

A: Illustrative plots of the D-PED volume of a 67-year-old patient. Linear regression analysis the growth rate was 0.012 mm³/mo. The eye received 4 times SML treatment at baseline, 4, 8, and 12mo separately. B: SD-OCT images showed the change of D-PED lesion against time.