Abstract
Purpose: :
To compare the changes of optic disc parameters of Heidelberg Retina Tomograph (HRT) before and after IOP reduction between primary angle–closure glaucoma (PACG) & primary open angle glaucoma (POAG.); To analyze the effect factors that may influence the changes and to investigate the cribrosa compliance in PACG & POAG.
Methods: :
We recruited 34 PACG patients (mean age 56.3+8.5) and 33 POAG patients (mean age 35.7+16.5). All patients underwent routine eye examinations including Goldman application tonometry, HRT and Humphrey 24–2 full threshold. PACG patients were treated with Laser peripheral iridotomy if 180°anterior chamber angle is still open otherwise trabeculotomy was done. POAG patients were underwent non–penetrating trabeculectomy if their IOP could not be controlled with two topical anti–glaucomatous medications. HRT was repeated one day after the IOP was reduced if the patient didn’t have surgery, and repeated one month later after surgery. T–test was used to compare the means of HRT parameters before and after IOP reduction in both PACG and POAG. General linear model was done to analyze the changes of optic disc HRT parameters with respect to the degree of post treatment reduction of IOP as well as baseline IOP, age, mean retinal thickness, c/d area ratio.
Results: :
Changes of cup depth, cup volume, cup area, rim area before and after IOP reduction are significantly different ( All P value are less than 0.01). Changes of all these parameters were not related to glaucoma diagnosis (POAG/PACG) as well as baseline IOP, age(P), but only mean cup depth change were related to the amount of IOP reduction (P=0.06), mean retinal thickness (P=0.029) and c/d area ratio(P=0.051).
Conclusions: :
This preliminary data shows no difference of cribrosa compliance between PACG and POAG, and the cribrosa compliance may related to the cup/disc ratio and related to the stage of glaucoma no matter it is either POAG or PACG.
Keywords: clinical research methodology • optic disc • lamina cribrosa