Effects of trabeculectomy on posture-induced intraocular pressure changes over time.
BACKGROUND
To determine whether trabeculectomy affects postural-induced changes in intraocular pressure (IOP), and whether it is maintained.


METHODS
Thirty-six eyes of 36 patients with open-angle glaucoma who were scheduled for their initial trabeculectomy with adjunctive mitomycin C were prospectively examined. The IOP was measured in the sitting and the lateral decubitus position with an ICare rebound tonometer before, and 1, 3, and 12 months after trabeculectomy.


RESULTS
Twenty-nine eyes of 29 patients completed this study. The mean baseline IOP measured with the ICare tonometer was 17.4 ± 4.9 mmHg in the sitting position and 21.3 ± 5.6 mmHg in the lateral decubitus position (p < 0.001). This postural IOP difference, +3.9 mmHg, was reduced to +1.3 ± 1.7 mmHg at 1 month and to +0.8 ± 1.5 mmHg at 3 months after the trabeculectomy (p < 0.001 and p = 0.004 respectively). This decrease in the degree of posture-dependent IOP change was maintained at +1.7 ± 2.2 mmHg at 1 year postoperatively (p < 0.001). In three cases, the postural IOP changes returned to the baseline level, and all three had a failed bleb.


CONCLUSIONS
Our results indicate that trabeculectomy not only reduces the IOP but also reduces the degree of posture-induced changes in the IOP. Our findings also speculate that measuring the postural IOP changes after trabeculectomy might provide a clue on the functioning of a filtering bleb.
Department of Ophthalmology, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu-shi 501-1194, Japan. sawadaa-gif@umin.ac.jp
Akira
A
Sawada
Tetsuya
T
Yamamoto
D000328:Adult; D000368:Aged; D000477:Alkylating Agents / Q000008:administration & dosage; D005260:Female; D005902:Glaucoma, Open-Angle / Q000503:physiopathology* / Q000601:surgery; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D016685:Mitomycin / Q000008:administration & dosage; D011187:Posture / Q000502:physiology*; D011446:Prospective Studies; D013997:Time Factors; D014065:Tonometry, Ocular; D014130:Trabeculectomy
D000477:Alkylating Agents; D016685:Mitomycin