Adopting 3-Year Screening Intervals for Sight-Threatening Retinal Vascular Lesions in Type 2 Diabetic Subjects Without Retinopathy

OBJECTIVE-To report the incidence of sight-threatening vascular lesions in type 2 diabetic subjects without retinopathy after adopting a 3-year interval screening program. RESEARCH DESIGN AND METHODS-In all, 1,691 type 2 diabetic subjects with no detectable retinopathy in two 50 degrees red-free fundus photographs were scheduled for follow-up with photography 3 years later. Age at diabetes diagnosis was 60 +/- 12 years, and known duration of diabetes was 6 +/- 6 years. Treatment consisted of diet only (26%), oral agents (54%), and oral agents and/or insulin (20%). Glycated hemoglobin A(1c) was 6.4 +/- 1.5%. RESULTS-Of the 1,322 subjects available for follow-up, 73% were still without retinopathy after 3 years, and 28% had developed mild or moderate retinopathy, but none developed severe nonproliferative or proliferative retinopathy. Macular edema requiring laser coagulation occurred in only one eye. CONCLUSIONS-Three-year retinal screening intervals can be recommended in subjects with mild type 2 diabetes and no retinopathy

Physiological response of the retinal pigmented epithelium to 3-ns pulse laser application, in vitro and in vivo

BACKGROUND: To treat healthy retinal pigmented epithelium (RPE) with the 3-ns retinal rejuvenation therapy (2RT) laser and to investigate the subsequent wound-healing response of these cells. METHODS: Primary rat RPE cells were treated with the 2RT laser at a range of energy settings. Treated cells were fixed up to 7 days post-irradiation and assessed for expression of proteins associated with wound-healing. For in vivo treatments, eyes of Dark Agouti rats were exposed to laser and tissues collected up to 7 days post-irradiation. Isolated wholemount RPE preparations were examined for structural and protein expression changes. RESULTS: Cultured RPE cells were ablated by 2RT laser in an energy-dependent manner. In all cases, the RPE cell layer repopulated completely within 7 days. Replenishment of RPE cells was associated with expression of the heat shock protein, Hsp27, the intermediate filament proteins, vimentin and nestin, and the cell cycle-associated protein, cyclin D1. Cellular tight junctions were lost in lased regions but re-expressed when cell replenishment was complete. In vivo, 2RT treatment gave rise to both an energy-dependent localised denudation of the RPE and the subsequent repopulation of lesion sites. Cell replenishment was associated with the increased expression of cyclin D1, vimentin and the heat shock proteins Hsp27 and αB-crystallin. CONCLUSIONS: The 2RT laser was able to target the RPE both in vitro and in vivo, causing debridement of the cells and the consequent stimulation of a wound-healing response leading to layer reformation.John P. M. Wood, Marzieh Tahmasebi, Robert J. Casson, Malcolm Plunkett, Glyn Chidlo