Abstract
Purpose :
To determine the effect of subthreshold macular laser treatment (SMLT) on visual acuity (VA) and macular volume (MV) in patients with non-center-involving diabetic macular edema (NCI-DME).
Methods :
Retrospective analysis of the change in VA and MV from baseline to the first review with data available 6-9 months following SMLT for NCI-DME.
Eligible eyes were those receiving SMLT for the first time in 2013-2018, with no co-pathology to account for the macular edema and no other ophthalmic treatment at the same time. Eyes treated with intravitreal injections or scatter laser before 6-9 months post-SMLT were excluded, as were those with missing data.
Stable VA was defined as a change of <0.1 LogMAR. MV was the total volume of the central 3mm of the retina, obtained from Heidelberg Spectralis® OCT scans. HbA1c levels from +/-3 months of the first SMLT were noted. A paired t-test was used for analysis and a p value of <0.05 was considered significant.
Secondary outcomes included the proportion of eyes having repeat SMLT before their 6-9 month visit. The proportion receiving repeat SMLT for NCI-DME or intravitreal injections for center-involving DME (>400 um in the central retina) at any time after the first SMLT was also evaluated.
Results :
185/364 eyes (148/293 patients) had complete VA datasets. 7 eyes lacked follow up OCT data. Table 1 shows participant demographics and baseline characteristics.
137 eyes (74%) had a stable VA, 22 (12%) improved, and 26 (14%) had a deterioration in VA at the 6-9 month visit. Mean VA increased by 0.02 LogMAR (p = 0.20) and mean MV increased by 0.04 (p = 0.05). Figure 1 illustrates the change in VA and MV.
SMLT was repeated for the same area of NCI-DME before the 6-9 month visit in 22 eyes (12%). Overall, 111 eyes (60%) have received additional treatment (SMLT and/or intravitreal injections for DME), beyond the baseline SMLT, to date, with a median follow up period of 694 days.
Conclusions :
These data suggest that a majority of eyes (86%) receiving SMLT for NCI-DME can achieve stable or improved VA over 6-9 months. On average, there was little change in the VA and MV, but the area of DME shifted with treatment in some cases. Over 50% of eyes required further DME treatment beyond their first SMLT. A prospective trial comparing SMLT vs observation-only vs intravitreal therapies for NCI-DME may shed more light on the best management option for these patients.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.