The Visual Field Ananlyses In The Advanced Stage Of Glaucoma Befor And After Controlling IOP With Trabeculectomy

Objective: To find whether the visual field changes of the advanced glaucoma are different between preoperative and postoperative. And to evaluate the relationship between the intraocular pressure and the damage of visual field.Methods: 44 cases (44 eyes) of advanced glaucoma with tubular visual field were tested with the static central visual fields by Humphrey 750 automated campimeter befor and after trabeculectomy. The results were divided into four quadrants as superior temporal, inferior temporal, superior nasal and inferior nasal. And each site of the four quadrants were numbered respectively (see Fig. 1).Then to compare the variations of each site's quantum, the mean sensitivity(MS) in the limited area(see Fig. 1) and full field, the mean defect(MD), and the pattern standard deviation(PSD) statistically between preoperative and postoperative , and to analyze the correlation between the intraocular pressure (IOP) and the corrected visual acuity, and between the intraocular pressure(IOP) and the aforesaid parameters about the visual field defect. And to compare the therapeutic effects of the trabeculectomy between primary open-angle glaucoma(POAG) and primary angle-closure glaucoma(PACG) in the advanced stage. Results: 1.The variations of each site's quantum in the limited area are not statistically significant(p>0.05); 2. The change of the average numbers of the residual sites shows a decreased tendency. Among the total, the number of the patients whose residual sites reduces account for 54. 5%;3. There are 42. 2% of the small numerus's sites(5～10dB and≤5dB) which quantums decrease to 0 postoperative. In contrast to it, there are only 9.4% of the large numerus's sites(>10dB) which quantums decrease to 0. That is to say the small numerus's sites have the higher operation risk;4. The average intraocular pressure reduces 10.46mmHg, and shows a statistical significance difference(t=6. 42, p<0. 01) after trabeculectomy. The variations of the corrected visual acuity and the parameters about the visual field defect have not significant difference(p>0.05), but present a increasing tendency, such as all patients' intraocular pressure have reduced after trabeculectomy, and there are 81. 8% of patients whose corrected visual acuity are not decreased and 45. 5% of patients whose mean sensitivity (MS) in the full field are increase; 5. Intraocular pressure is in direct correlation with the aforesaid parameters about the visual field defect Preoperative and postoperative(p<0.01) but is not in statistical correlation with corrected visual acuity(p>0.05); 6. There are not significant difference between the advanced POAG patients and the advanced PACG patients after trabeculectomy(p>0.05).Conclusion: 1. The visual function of the advanced glaucoma are not aggravated after trabeculectomy; 2. To control intraocular pressure (I0P) is beneficial for preventing more visual field defect of the advanced glaucoma; 3. We should cautiously make the decision whether trabeculectomy should be take to cure the advanced glaucoma patients when their majority sites' quantums are not more than 10dB in the visualfield map, especially those which are less than 5dB.