Objective To investigate the early effects of intervention with tanakan on retinal function in diabetic retinopathy(DR) after laser photocoagulation. Methods Prospective random controlled study was performed on 60 Patients (60 eyes) from 23 to 69 years old with DR(phase Ⅲ～Ⅳ). The multifocal electroretinograms (MERG) were tested with VERIS Ⅳ before, the 3rd day and the 7th day after photocoagulation. Results No significant differences were found in the latencies and response densities of N1,P1 and N2 between the two groups before photocoagulation. Compared with that before photocoagulation, three days after photocoagulation the latencies in tanakan group had no significant change. The response densities of N1,P1 and N2 reduced and the changes were much smaller than that in control. Three days after photocoagulation, the response densities of P1 and N2 in the central macula 5°area were much higher and the latencies of P1 and N2 were significantly shorter than that in control group. There were no significant differences in the response densities in the 7th day and the differences in the latencies between two groups still existed. Conclusion Tanakan may be effective in preventing the retina from damage of retinal photocoagulation in some degree in DR. (Chin J Ocul Fundus Dis, 2002, 18: 208-211)
Purpose To evaluate the safety and efficacy of draining subretinal fluid with transchoroidal probing by using the traditional needling and diode endolaser probing. Methods The investigation included 70 consecutive patients(74 eyes) with rhegmatogenous retinal detachment undergoing scleral buckling surgery.Seventy cases were randomly divided into 2 groups,group A 34 cases(36 eyes)with the needle drainage procedure and group B 36 cases(38 eyes) with the diode probe respectively.The safety and efficacy were compared in between the 2 groups. Results No operative failure was found in these 2 groups.In group A,subretinal hemorrhage occurred in 3 eyes,and retinal incarceration,retinal preforation in one eye. No significant complication occurred in group B. Conclusion Diode laser drainage has the advantage in that it may reduce the incidence of operative complication with drainage.This technique might be used in any case requiring drainage of subretinal fluid especially of rhegmat ogenous retinal detachment in cases of shallow retinal detachment. (Chin J Ocul Fundus Dis,1998,14:202-203)
ObjectiveTo observe clinical outcomes of laser photocoagulation on retinopathy of prematurity (ROP). MethodsClinical data of 64 cases of ROP infants (127 eyes) were studied retrospectively. Fifteen infants (30 eyes) were diagnosed of pre-threshold ROP (type Ⅰ, 23.6%) and 49 cases (97 eyes) of threshold ROP (76.4%). All the eyes underwent photocoagulation through binocular indirect ophthalmoscope (532 nm or 810 nm) within 72 hours after the confirmation ROP. In all the 15 cases (30 eyes) of pre-threshold ROP (type Ⅰ), 6 of them (12 eyes) were photocoagulated by laser of 532 nm, and the other 9 ones (18 eyes) were treated with 810 nm. In 49 threshold ROP infants (97 eyes), 37 cases (73 eyes) and 12 ones (24 eyes) were treated with laser of 532 nm or 810 nm respectively. All the infants were followed up 12-36 months (18.4 months) since photocoagulation to investigate regression of ROP. All the data of ROP infants photocoagulated, such as recovery rate of one-time photocoagulation, repeat rate, unfavorable outcomes, and complications, were analyzed statistically according to the severity of ROP and wave length of laser employed. ResultsIn all the 127 photocoagulation treated eyes, ROP regressed completely in 125 eyes (98.4%), temporal retinal traction remained in 2 eyes (1.6%), and no retinal detachment was found. ROP regressed completely in 118 eyes (92.9%) after one-time photocoagulation, recovered totally in 6 eyes (4.7%) after repeating photocoagulation 2-3 times, and resorted to cryotherapy in 3 eyes (2.4%). Subconjunctiva hemorrhage, found in 12 eyes (9.4%), was the most common complication. During photocoagulation, anesthetic accident occurred in 1 infant (1.6%), and 1 eye developed cataract (0.8%). It was suggested from statistical analysis that there was no significant difference on efficiency or safety between pre-threshold (type Ⅰ) and threshold ROP photocoagulated by laser of 532 nm or 810 nm. However, almost all of the ROP infants need repeat photocoagulation or additional cryotherapy, and patients with unfavorable outcomes or severe complications, occurred in threshold ROP treated with 532 nm laser. ConclusionPhotocoagulation with 532 nm or 810 nm laser is effective for type Ⅰ pre-threshold or threshold ROP.
Objective To observe the development of cone/rod functions in children with retinopathy of prematurity (ROP) after laser photocoagulation. Methods 30 ROP patients (60 eyes) treated with laser photocoagulation (case group) and 30 preterm infants (60 eyes) without ROP (control group) were enrolled in this study. Flash Electroretinogram (F-ERG) was performed on all the children, and the response of rod cells and cone cells, maximal mixed responses and oscillatory potentials were recorded. Results Compared with the control group, the amplitude of response of rod cells was obviously decreased (t=-2.385, P＜0.05), while the latency phase of rod cells was obviously prolonged (t=-2.799,P＜0.05); the amplitudes of a-and b-wave of maximal response were significantly decreased in the case group (t=-2.967, -4.037; P＜0.05). But there was no significant difference of amplitudes(t=-1.402) and latency phase (t=-1.637,0.465)of b-/a-wave of the maximal mixed response between two groups(P＞0.05). In the response of cone cells, there was no significant difference of the latency phase (t=1.222) and amplitude (t=-0.636)of a-wave as well as amplitude (t=-1.927) of b-wave between two groups (P＞0.05). The latency phase of b-wave of cone cells in the case group was longer than that in the control group (t=-2.466,P＜0.05). Conclusions Compared to no-ROP preterm infant retina, laser-treated ROP retina has normal cone function development and delayed rod function development.
Purpose To study an animal model of retinal sheets transplantation using excimer laser. Methods A layer of pure photoreceptors was got by the use of excimer laser.Then the photoreceptor layer was transplanted to the subretinal space of the adult RCS rats which were an animal model of inherited retinal degeneration.The globes were enucleated one month after transplantation.Sections were made for light microscopic examninations. Results A layer of pure and uniform photoreceptors can be got by the use of excimer laser.The transplanted photoreceptors survived well in the subretinal space. Conclusion Retinal sheets transplantation using excimer laser can provide us with well oriented retinal construction and more photoreceptors after transplantation. (Chin J Ocul Fundus Dis,1998,14:209-211)
ObjectivesTo evaluate the therapeutic effect of argon laser photocoagulation combined with intravitreous injection of triamcinolone acetonide (TA) on ischemic central retinal vein occlusion (CRVO).MethodsArgon laser photocoagulation combined with intravitreous injection of TA was performed on 17 patients (17 eyes) with CRVO between December 2003 and July 2004.ResultsDuring the follow-up of 4-10 months, the visual acuity improved in 16 patients, including alleviated or even disappeared cystoid macular edema (CME) in 5, and recurred macular edema in 5 with decreased visual acuity after 3 months. Six patients had increased ocular pressure after intra-ocular injection which alleviated after treated suitably. No neovascularization in angle or secondary neovascular glaucoma was found.ConclusionArgon laser photocoagulation combined with intravitreous injection of TA may improve the visual acuity and reduce complications in ischemic CRVO, though macular edema may recur in some cases. (Chin J Ocul Fundus Dis, 2005,21:224-225)
Macular edema is a common cause of visual loss in patients with retinal vascular diseases represented by diabetic retinopathy and retinal vein occlusion. Laser photocoagulation has been the main treatment for this kind of diseases for decades. With the advent of antagonist of vascular endothelial growth factor and dexamethasone implant, diabetic macular edema and macular edema secondary to retinal vein occlusion have been well controlled; the use of laser therapy is decreasing. However, considering possible risks and complications, lack of extended inspection of efficacy and safety of intravitreal pharmacotherapy, laser therapy cannot be replaced by now. Therefore, the efficacy and safety of laser therapy will improve by sober realization of role of photocoagulation and proper selection of treatment indication.
In recent years, the subthreshold micropulse laser is a kind of laser mode which is characterized by long intermittence. It achieves effective therapeutic effect while minimizes the damage to tissues. At present, it has been used to treat diabetic macular edema. Early studies suggested that the laser selectively acts on retinal pigment epithelial cells to reduce macular edema by regulating the expression of inflammatory biomarkers, growth factors, heat shock proteins and other substances. In recent years, with the development of research, more and more emphasis has been placed on the role of retinal glial cells. Müller cells are also considered as one of the target cells affected by micropulse laser, but there is no evidence of direct or indirect effects of micropulse laser on Müller cells. In the near future, it is expected that we will have more clinical evidence to confirm the target cells of the micropulse laser, which may be further confirmed by in vitro experiments through Müller cells or Müller cells co-cultured with retina pigment epithelium cells, so as to make a more detailed statement on the mechanism of it.
The threshold micropulse laser is widely used in clinical practice as a safe, non-invasive laser for avariety of macular diseases. Compared with the conventional laser therapy, the subthreshold micropulse laser is selectively absorbed by the RPE and therefore it does not cause retinal damage. To explore the therapeutic mechanism and the safety, development of threshold micropulse laser in the treatment of various common macular diseases, and further clarify its indications and advantages, which are helpful for its wider clinical application.