Histopathological changes in retinas and F-ERG features of streptozotocin-induced diabetic rats treated with ozone

AIM： To study the histopathological changes in the retina and flash electroretinogram （F-ERG） features of ozone-treated streptozotocin （STZ）-induced diabetic rats. METHODS： Seventy male Sprague Dawley rats were grouped as follows： blank group （GB, n=10）, model control group （GM, n=18）, ozone group （GOs, n=19）, and oxygen group （GO2, n=18）. The model was induced by single intraperitoneal injection of STZ. Ozone or oxygen enteroclysm was given twice per week for 4wk. F-ERG and histopathological examinations were performed one month after treatment. RESULTS： Under dark adaption, as compared to GB, the other groups each had differential decreases in the a-wave amplitudes （P〈0.05）; the latencies were delayed in GM, GO2, and GO3 rats （P〈0.05）. Similar results were observed under light adaption, with the exception that the a-wave of the amplitudes （F=0.28, P〉0.05）. There were significant differences in the apoptosis index among the groups （P〈0.05）. Under ozone treatment, apoptosis was decreased in GO3 as compared to GM and GO2 . CONCLUSION： Ozone administration alleviates nerve damage and reduces pathology and apoptosis in the retinas of diabetic rats.

Retinal ganglion cell complex changes using spectral domain optical coherence tomography in diabetic patients without retinopathy

AIM：To assess the ganglion cell complex（GCC）thickness in diabetic eyes without retinopathy. METHODS：Two groups included 45 diabetic eyes without retinopathy and 21 non diabetic eyes. All subjects underwent full medical and ophthalmological history,full ophthalmological examination,measuring GCC thickness and central foveal thickness（CFT）using the RTVue~？ spectral domainoptical coherence tomography（SD-OCT）,and HbA1C level.RESULTS：GCC focal loss volume（FLV%）was significantly more in diabetic eyes（22.2% below normal）than normal eyes（P=0.024）. No statistically significant difference was found between the diabetic group and the control group regarding GCC global loss volume（GLV%）（P=0.160）. CFT was positively correlated to the average,superior and inferior GCC（P=0.001,0.000 and 0.001 respectively）and negatively correlated to GLV% and FLV%（P=0.002 and0.031 respectively）in diabetic eyes. C/D ratio in diabetic eyes was negatively correlated to average,superior and inferior GCC（P=0.015,0.007 and 0.017 respectively）. The FLV% was negatively correlated to the refraction and level of Hb A1c（P=0.019 and 0.013 respectively）and positively correlated to the best corrected visual acuity（BCVA）in log MAR in diabetic group（P=0.004）.CONCLUSION：Significant GCC thinning in diabetes predates retinal vasculopathy,which is mainly focal rather than diffuse. It has no preference to either the superior or inferior halves of the macula. Increase of myopic error is significantly accompanied with increased focal GCC loss. GCC loss is accompanied with increased C/D ratio in diabetic eyes.

Intravitreal dexamethasone implants for diabetic macular edema

AIM： To evaluate the safety and efficacy of a dexamethasone（DEX） intravitreal implant for diabetic macular edema（DME）.METHODS： Totally 113 eyes of 84 patients were divided in three subgroups： naive patients（n=11）, pseudophakic patients（n=72） and phakic patients（n=30）. Inclusive criterion comprised adult diabetic patients with central fovea thickening and impaired visual acuity resulting from DME for whom previous standard treatments showed no improvement in both central macular thickness（CMT） and best corrected visual acuity（BCVA） after at least 3 mo of treatment. Outcome data were obtained from patient visits at baseline and at months 1, 3, 5, 9 and 12 after the first DEX implant injection. At each of these visits, patients underwent measurement of BCVA, a complete eye examination and measurement of CMT and macular volume（MV） carried out with optical coherence tomography（OCT） images. RESULTS： Seventy-three eyes（64.5%） received a single implant, 30（26.5%） received two implants and 10（9%） received three implants. At baseline, average in BCVA, CMT and MV were 43.5±20.8, 462.8±145 and 12.6±2.5 respectively. These values improved significantly at 1 mo（BCVA： 47.2±19.5, CMT： 339.6±120, MV： 11.11±1.4） and 3 mo（BCVA： 53.2±18.1, CMT： 353.8±141, MV： 11.3±1.3）（P≤0.05）. At 5 mo（BCVA： 50.9±19.8, CMT： 425±150, MV： 12.27±2.3）, 9 mo（BCVA： 48.4±17.6, CMT： 445.5±170, MV： 12.5±2.3） and 12 mo（BCVA： 47.7±18.8, CMT： 413.2±149, MV： 12.03±2.5）, improvements in the three parameters were no longer statistically significant and decreased progressively but did not reach baseline values. There were no clinical differences between subgroups. Ocular complications were minimal.CONCLUSION： Patients with DEX implants show maximum efficacy at 3 mo which then declined progressively, but is still better than baseline values at the end of follow-up.