Comparing Clinical Effect Of Two Different Methods In Treatment Of Neovascular Glaucoma

Neovascular glaucoma(NVG)can be caused by many ocular diseases. It is the most common type of refractory glaucoma. The rate of leading to blind can reach to 92.4%.Drug treatment is in poor. The success rate of filtration surgery was only 11～33% but with many intraoperative and postoperative compl- ications . So its therapy is very complicated and difficult. In recent years ciliary body destruction operation to treatment refractory glaucoma by the semico- nductor diode laser was used at home and abroad and more articles have been reported,but comparison the effect of transscleral cyclophotocoagulation (TSCPC) and cyclocryotherapy of two different surgical treatment for andvanced NVG is rare.This retrospective paper is to analyse postoperative intraocular pressure(IOP), visual acuity,pain, postoperative complications and other conditions of diode laser TSCPC and cyclocryotherapy, to evaluate clinical effect of two different methods for the treatment of advanced NVG.We collected the patients of NVG 50 cases(50 eyes) in General Hospital of Daqing Oil Field of Hei Longjiang Province from 2008.1 to 2009.10 . 50 eyes of 50 patients with NVG were divided at random into two groups: 26 cases(26 eyes) treated by TSCPC, and 24 cases(24 eyes) treated by cyclocryotherapy. The laser parameters of TSCPC: 1.9-2.3w power,2s exposure, and 18～22 shots in 270°range. The parameters of cyclocryotherapy: -70℃temperature, 60s of every spot,6～8 spots in 180°range. To follow up and document preoperative IOP, postoperative IOPs, visual acuity, pain, postoperative complications on 1 day, on 3 day, and at 1week , and in 1,3,6 months. Outcome measures (1) IOP: IOP measured before surgery and on 1 day ,3 day, at 1 week, in 1, 3, 6 months after surgery.(2)Eye examination: routine visual acuity, slit lamp examination, observe the postoperative reaction and complications (including postoperative ocular pain, corneal edema, anterior chamber fibrin exudate, hyphema, lens opacity increased, light loss, low eye pressure or eyeball atrophy). (3)Drug use: record drugs of patients used before and after operation of reducing intraocular pressure and stop bleeding and pain. (4)Follow-up time: on 1 day, on 3 day, at 1 week, in 1 month, in 3 month, in 6 month after operation. Efficiency was defined as IOP less than or eaqual to 21mmHg ,or IOP decreasing 30 percent than preoperative or absence of pain for blind eyes.Follow-up observations were made for all patients for 6 months.All the data obtained in the study were analysed statistically by SPSS13.0 softwear.The results of the study show(1)There were no significant differences between the two groups in preoperative IOP and visual acuity(p>0.05). There was a significant difference between preoperative IOP and postoperative IOP in the two groups except on the first day after cyclocryotherapy(p<0.001). IOP on the first day, on the third day and at the first week after TSCPC were 27.44±4.95mmHg,22.72±4.64mmHg,17.23±3.63mmHg respectively. IOP after cycloc- ryotherapy in the same time were 54.15±6.40mmHg,45.36±4.51mmHg,35.03±5.77mmHg respectively.In comparison with TSCPC,there was a signif- icant difference in postoperative IOP .(p<0.001). IOP in the first month, in the third month and in the sixth month after TSCPC were18.13±5.67mmHg,20.34±7.61mmHg,24.37±9.39mmHg respectively.IOP in the same time after cyclocryotherapy were18.72±4.39mmHg,21.56±8.17mmHg,24.47±10.64mmHg respectively.In comparison with TSCPC, there were no significant differences in postoperative IOP(p>0.05)(.2)In this study, statistics only light perception and over light perception vision of these patients preoperatively. at the end of follow up, 13 eyes (86.7%) visual acuity improved or unchanged in TSCPC group,2 (13.3%)of 13 eyes had improved visual acuity, 11 eyes had no change; decreased in 2 eyes (13.3%).9 eyes (60%) visual acuity improved or unchanged in cyclocryotherapy group,no visual acuity improved;6 eyes (40%) the preoperative light perception or index decreased to varying degrees. There was no significant difference between the two groups in postoperative visual acuity(p>0.05).(3)Early postoperative eye pain: All patients of TSCPC group and cyclocryotherapy group had postoperative eye pain within a week, Time of pain in TSCPC group was 1.38±0.64 days compare with 3.63±1.25 days in cyclocryotherapy group. The time of pain was shorter in TSCPC group than that in cyclocryotherapy group. There was a significant difference between the two groups in the early postoperative time (p <0.001) (.4)The incidence of complications postoperative:corneal edema ,9 eyes in TSCPC group ,2 eyes in cyclocryotherapy group .fibrin in anterior chamber, 6eyes in TSCPC group, 1 eye in cyclocryotherapy group .corneal edema and fibrin in anterior chamber in TSCPC group was lower than that in cyclocryotherapy group .There was significant difference between the two groups in postoperative corneal edema and fibrin in anterior chamber(p<0.05).The incidence of hyphema, lens opacities increase and the loss of light perception after operation showed no significant differences between the two groups (p> 0.05). There were no serious complications postoperative in two groups. (5)The effect of treatment: The operating efficiency is 87.5% and pain relief rate is 96.2% in TSCPC group. The operating efficiency is 79.2% and pain relief rate is 88.5 % in cyclocryotherapy group. The operating efficiency were not significantly different between the two group by the end of follow-up(p>0.05). Postoperative intraocular pressure is over 6mmHg in all patients with no hypotony occurred. The Clinical data showed : IOP decreased significantly in TSCPC group on 1day postoperative,while the IOP in cyclocryotherapy group decreased signific- antly only on the 3rd day postoperative. IOP in the group decreased gradually. and the majority of eyes in cyclocryotherapy group reached the effective treatment for IOP until after a week . Comparison between the two groups during the same period for postoperative IOP show difference is significant after 1d, 3 d, 1w(p<0.001).In addition ,there was no significant IOP reduction in cyclocryo- therapy group 1 day after surgery .Instead, IOPs of 5 eyes were higher than the preoperative IOPs, There is no increase in IOP transient in TSCPC group. Therefore we support the Zhou Wenbing's view of cyclocryotherapy can lead to sharp sclera contraction, the change of ocular contents lead to IOP elevation. Geyer's study also found that ice-body can form in the eyes in the low temperature of cyclocryotherapy, When Intraocular liquid changing into solid ice-body the Intraocular volume will increas by 8%. It can lead to a sharp transient increase in IOP. This shows TSCPC can reduce IOP rapidly and substantially in the short period after surgery. The reduction of IOP in cyclocryotherapy group is slowly. Following the procedure can produce a transient high IOP and further damage to visual function. But TSCPC can not produce a transient elevation of IOP .In terms of the IOP reduced range, speed and the impact on visual function TSCPC is better than cyclocryotherapy significantly. IOP in two groups After surgery 1,3,6 month comparing with preoperative IOP is different, The differences were statistically significant (p<0.001).Comparison for postoperative IOP during the same period shows IOP difference between the two groups had no significant after 1 m, 3 m, 6 m(p>0.05).The two different methods is similar to long-term effects of reducing IOP. Although the statistical results of two surgical effect on visual acuity was no significant difference. postoperative visual acuity of 2 eyes improved in TSCPC group .There is no postoperative visual acuity improving in cyclocryotherapy group .This indicates that the damage of visual function of TSCPC is less than of cyclocryotherapy. Rapid reducing of IOP by TSCPC may be relieve ischemia of eye so that postoperative visual acuity was improved. Therefore, we propose TSCPC should be operated before completely impaired visual function .Early postoperative pain was significantly shorter in TSCPC group than in cyclocryo- therapy group. The difference of early postoperative pain time in two groups were statistically significant (p<0.001). Research shows that diode laser can destroy the nerve endings of dominating pain in the ciliary body. If IOP can be reduced 30 percent lower than the initial IOP the pain of eye will disappear .TSCPC can relieve pain more quickly. First of all, we consider it has something to do with reducing of IOP more than 30%. Second, because of its damage to the ciliary body is limited the surrounding tissue was not damaged. Then, there is a slight postoperative inflammatory reaction. We thought The results of our analysis are that damage of TSCPC is limited. The surrounding tissue is not affected in TSCPC. The postoperative inflammatory response is generated and small. On the contrary, the damage of ciliary body is a wide range by cyclocryotherapy. The pathology resultes in cyclocryotherapy showed that there is also some thrombosis forming in blood vessels in non-condensing zone. Early postoperative corneal edema and anterior chamber inflammatory reaction in cyclocryotherapy group was significantly higher than in TSCPC group. We believe that it is related to the facts that diode laser can selectively destroy the ciliary body and damage of tissues was limited. Therefore, TSCPC is better than cyclocryotherapy significantly.Summing up, the two surgical methods for the treatment of advanced NVG in the control of IOP and pain relief have a significant effect. Compared with cyclocryotherapy, IOP of TSCPC can drop dramatically within a short period. And pain of eyes can be relieved rapidly with fewer complications. Therefore , TSCPC is an effective and safe method relatively for the treatment of advanced NVG. TSCPC should be complicated widely.