Diabetic macular edema: classification,medical and laser therapy

Purpose. to propose and describe a new classification of diabetic macular edema (DME) based on its etiopathogenetic features and to present efficacy and safety data on medical and laser treatments currently used and under investigation. Methods. available literature on DME has been reviewed and information provided by contact lens biomicroscopy, fluorescein angiography and optical coherence tomomography has been combined; published data from trials and reports investigating effectiveness of medical and laser treatments were also analyzed. Results. DME was classified according to its main etiopathogenetic components: prevalently retinovascular, tractional and with taut attached posterior hyaloid, each of them having peculiar aspects on fundus, angiographic and tomographic examination. Focal laser treatment remains the only effective intervention, as shown by a large randomized controlled trial, but new less-invasive photocoagulation strategies (i.e., light laser photocoagulation and subthreshold micropulse diode laser) as well as pharmacological approaches (i.e., antioxidants, PKC inhibitors, aldose-reductase and AGE inhibitors, VEGF inhibitors, intravitreal triamcinolone) are emerging. Conclusions. based on our review a classification of DME was developed that may prove useful in making the appropriate treatment decision; the new laser and pharmacological treatments currently investigated are promising and need to be confirmed by large, controlled clinical trials.     

HLA-A29-Positive Uveitis: Birdshot Chorioretinopathy,What Else?

Birdshot chorioretinopathy (BSCR) is a relatively rare form of uveitis, which is strongly correlated with the histocompatibility leukocyte antigen (HLA)-A29 class I type. Nevertheless, HLA typing is not diagnostic. The purpose of the present study was to retrospectively evaluate the ocular manifestations associated with the presence of HLA-A29 other than typical BSCR. Charts of consecutive patients with a diagnosis of intraocular inflammation and who were found to be positive for the presence of HLA-A29 were retrospectively reviewed. Only 7 patients met the criteria for a definite diagnosis of BSCR. Among the other 11 patients, the disease was bilateral in 7 patients and unilateral in 4 patients. A definite diagnosis of the following conditions were found: intraocular and CNS lymphoma in 1 patient, posterior tubercular uveitis with occlusive vasculitis in 1 patient, latent ocular tuberculosis in 1 patient, Fuchs’ uveitis in 1 patient, herpetic panuveitis in 1 patient and HLA-B27 anterior uveitis in another patient. Although BSCR is strongly related to the HLA-A29 phenotype, and its presence confers a relative risk of disease, the definite diagnosis requires specific ocular characteristics. HLA-A29 typing alone is not a diagnostic requirement for the definite diagnosis of BSCR and should only be considered as a supportive finding.Key words: Birdshot chorioretinopathy, Epidemiology, HLA-A29, Uveitis     

Genetics of diabetic retinopathy

The purpose was to investigate the effect of decentered ablation in myopic corneal refractive surgery by simulation. Wavefront aberrations in a small pupil area (radius: 2 mm) for photopic vision and in a large pupil area (radius: 3 mm) for mesopic vision with simulated refractive surgery were analyzed using Zernike polynomials. Radii of ablation were 3, 2.5 and 2 mm. Decentrations of ablation were 0 mm and 0.5 mm. Change of the surface shape by ablation was considered a perturbation, while Gullstrand’s schematic eye was used as un-perturbed optics. For photopic vision, wavefront aberrations were about the same as with unperturbed optics. For mesopic vision, the results were heavily dependent on the radius of ablation area. When the radius was 3 mm, wavefront aberrations did not increase very much compared to un-perturbed optics. When the radius was smaller than 3 mm, spherical aberration was induced by centered ablations, and coma was also induced by decentered ablations. In conclusion, small ablation areas or subclinical decentrations of ablations could cause serious amounts of wavefront aberrations to the optics of the eye in the simulations.     

Optical coherence tomography of subfoveal choroidal neovascularization treated with transpupillary thermotherapy

Transpupillary thermotherapy (TTT) has been proposed as a new treatment modality for choroidal neovascularization (CNV). Most studies conducted show decreased exudation due to CNV and reduction of subretinal elevation. Optical coherence tomography (OCT) shows a dynamic sequence of changes early after treatment. Within 1 hour after TTT, OCT shows increased retinal thickness and intraretinal fluid with retinal elevation. One week after treatment, OCT shows decreased subretinal and intraretinal fluid and diminished retinal elevation. OCT can be a valuable method to assess the early effect of TTT. A placebo-controlled, multi-center trial (TTT4CNV) evaluating the long-term efficacy and visual implications of TTT in occult CNV is underway.     

Evidence for Anti-VEGF Treatment of Diabetic Macular Edema

Diabetic macular edema (DME) is the most important cause of vision loss in patients with diabetes mellitus. Diabetic retinopathy has a remarkable impact on public health and on the quality of life of diabetic patients and thus requires special consideration. The first line of treatment remains the management of systemic risk factors but is often insufficient in controlling DME and currently, laser retinal photocoagulation is considered the standard of care. However, laser treatment reduces the risk of moderate visual loss by approximately 50% without guaranteeing remarkable effects on visual improvement. For these reasons, new strategies in the treatment of DME have been studied, in particular the use of anti-vascular endothelial growth factor (anti-VEGF) drugs. VEGF is a pluripotent growth factor that acts as a vasopermeability factor and an endothelial cell mitogen. For this reason, it represents an interesting candidate as a therapeutic target for the treatment of DME. The aim of this article is to review the evidence behind the use of anti-VEGF drugs in the treatment of DME.     

Enhanced depth imaging optical coherence tomography in type 2 diabetes

Purpose. To investigate the changes in macular choroidal thickness in eyes with various stages of diabetic retinopathy, using enhanced depth imaging optical coherence tomography (EDI OCT). Methods. Sixty-three consecutive diabetic patients-who presented without diabetic retinopathy (NDR); with diabetic retinopathy (nonproliferative diabetic retinopathy [NPDR]) and no clinically significant macular edema (CSME-); or with NDPR and clinically significant macular edema (CSME+)-underwent EDI OCT. Twenty-one age- and sex-matched healthy subjects (21 eyes) also underwent EDI OCT. Results. A total of 63 eyes of 63 consecutive diabetic patients (26 female [41.2%]; mean age 65 ± 9 years, range 48-83 years) were included in the analysis. Mean best-corrected visual acuity was 0.13 ± 0.25 LogMAR (range 0-1). Mean CMT was 272.5 ± 16.2 μm in 21 NDR eyes, 294.5 ± 23.5 μm in 21 NPDR/CSME- eyes, and 385.6 ± 75.1 μm in 21 NPDR/CSME+ eyes. There was no difference in mean subfoveal choroidal thickness among each diabetic group (238.4 ± 47.9 μm [NDR], 207.0 ± 55.9 μm [NPDR/CSME-], 190.8 ± 48.4 μm [NPDR/CSME+]; P = 0.23). The mean subfoveal choroidal thickness was significantly reduced in each diabetic group compared with the control group (309.8 ± 58.5 μm, P < 0.001). Conclusions. In diabetic eyes, there is an overall thinning of the choroid on EDI OCT. A decreased choroidal thickness may lead to tissue hypoxia and consequently increase the level of VEGF, resulting in the breakdown of the blood-retinal barrier and development of macular edema.     

Vascularized retinal pigment epithelial detachment in age-related macular degeneration: treatment and RPE tear incidence

Background

To review vascularized-pigment epithelial detachment (V-PED) treatment visual outcome, and to assess acute retinal pigment epithelium (RPE) tear incidence.

Methods

One hundred and thirty-two eyes of 125 consecutive patients with age-related macular degeneration and V-PED were included. Ninety-four eyes (71.2%) were associated with choroidal new vessels (CNV), 38 (28.8%) with retinal angiomatous proliferation (RAP). Patients, treated over a 10-year period with the time-current therapy, received: verteporfin photodynamic therapy (PDT) (group 1, 38 eyes), combined intravitreal triamcinolone acetonide (IVTA) and PDT (group 2, 44 eyes) or intravitreal anti-VEGF injection (bevacizumab or ranibizumab) (group 3, 50 eyes).

Results

Mean follow-up was 20.5?months. At month 12, all eyes treated with PDT or with IVTA and PDT showed a mean significant severe visual decrease. Eyes with CNV lost ?0.67 and ?0.37 logMAR (p?p?p?p?=?0.01 respectively). RPE tear occurred in 14 eyes (36.8%) and in six eyes (13.6%) in groups 1 and 2 respectively. Eyes treated with anti-VEGF therapy showed slight mean visual acuity decrease at month 12. Those with CNV had a mean baseline best-corrected visual acuity (BCVA) of 0.36 ±?0.24 logMAR, final of 0.44 ±?0.30 logMAR (?0.08 logMAR, n.s.). In eyes with RAP, mean baseline BCVA was 0.58 ±?0.39 logMAR, final was 0.78 ±?0.47 logMAR (?0.20 logMAR, n.s.). RPE tear occurred in 14 eyes (36.8%). Patients with either V-PED with CNV or a better baseline BCVA showed greater risk of acute RPE tear (p?=?0.01 and p?=?0.003 respectively).

Conclusions

Effective treatment for vascularized PED is still lacking. Until now, only stabilization of the disease has been achieved using anti-VEGF therapy, but the risk of RPE tear can further hamper our expectations. Baseline characteristics are helpful for prognosis, but patients must be informed of the uncertain response. New therapeutic strategies are needed.