Diode laser, vitrectomy and intravitreal triamcinolone. A comparative study for the treatment of diffuse non tractional diabetic macular edema.

PURPOSE: To determine the effectiveness and safety of diode laser, pars plana vitrectomy (PPV) with gas tamponade, and intravitreal triamcinolone (IVT) as possible treatments for diffuse diabetic macular edema (dDME). To determine whether the new macular edema Classification previously proposed by some of the authors may help as a guide in the choice of treatment. METHODS: A retrospective, comparative study of 169 eyes with dDME that underwent treatment. The eyes divided into 3 groups: in the PPV Group, 59 eyes received PPV with gas tamponade; in the DIODE Group, 53 eyes received a laser grid; in the IVT Group, 57 eyes received an intravitreal injection of 4 mg of triamcinolone acetonide. The follow up ranged from 6 to 24 months. The eyes were classified according to the new DME Classification based on OCT. MAIN OUTCOMES: Change in foveal thickness as determined by Optical Coherence Tomography (OCT); change in visual acuity; intra and postoperative complications. RESULTS: Mean visual acuity (VA) improved at 3 months with every treatment. At one year only eyes which underwent PPV still had better VA than the pre-op value, while eyes which underwent IVT and laser treatment showed regression. PPV show the greater percentage of eyes which gain 3 or more lines of VA at one year (17%). Mean foveal thickness improved at 3 months with every treatment. Only the eyes into the PPV Group showed relatively low foveal thickness at one year. Better final VA and foveal thickness were obtained if preop VA is > or = 0.3 and if earlier stages of DME were treated according to the new DME Classification. PPV was the treatment which offered the most stable results with at one year or longer. Similar results were observed into the PPV Groups as a whole and into a subgroup of eyes with preoperative PVD. No complications were encountered with laser diode treatment. Long term complications into the IVT Group were elevated IOP (8%), retinal detachment (3.5%) and posterior cataract (15%). Long term complications into the PPV Group were retinal detachment (3.4%) and cataract (90%). CONCLUSIONS: Diode laser, PPV with gas tamponade and IVT are effective alternative treatments to decrease foveal thickness and improve visual acuity in eyes with DME. However while the results of PPV are stable in the long term follow-up, diode laser and IVT do not offer stable results. Complications may be severe with PPV and IVT. It is necessary to carefully select cases which would benefit from these types of treatments. The authors think that the OCT Classification may serve as a guide for the choice of treatment.

Diabetic macular edema: an OCT-based classification.

PURPOSE: More than ten years after ETDRS, Optical Coherence Tomography (OCT) greatly enhanced our ability to detect macular thickening and has brought new insights on the morphology of edema and on the presence of vitreal traction. In this study we propose a new classification of macular edema based on OCT findings to better catalogue and follow this complex clinical entity. METHODS: Since January 2000 we analysed with OCT 2 (Zeiss Inc.) more than one thousand and two hundred eyes with DME. RESULTS: The classification takes into account five parameters: retinal thickness, diffusion, volume, morphology and presence of vitreous traction. Standard figures and numerical values for every parameter are given. CONCLUSION: Although ETDRS guidelines for laser treatment of DME still remain the only proven therapy for this condition, many other strategies are now on trial, and the vast majority of authors use OCT as the best indicator of therapeutic benefit. The amount of information given by OCT demonstrates that macular edema is a complex clinical entity with various morphology and gravity, and disclaimed the limitations of a simple "clinical" definition. As in many other examples such as macular holes and choroidal neovascularization, a uniform and precise definition of macular edema would increase the possibility to compare and judge the result of different therapeutic strategies. Aim of this classification is to implement the ETDRS clinical definition of DME with the precise and useful data given by OCT to better diagnose, catalogue and follow macular edema.