Abstract
Purpose: :
Decrease in intraocular pressure (IOP) after cataract surgery has been reported both in normal eyes and eyes with open angle glaucoma. The aim of this study was to evaluate the data from ultrasound biomicroscopy (UBM) and biometry concerning eyes with narrow angle glaucoma which did not need any IOP lowering medication after phacoemulsification.
Methods: :
The charts of 41 consecutive eyes with occludable angle, elevated IOP prior to medical treatment, mostly early perimetric defects and patent YAG laser iridotomy were reviewed. All eyes had UBM examination and A–scan biometry ; anterior chamber central depth (ACD), angle width (AW), lens thickness (LT), axial length (AL) and central corneal thickness (CCT) were measured. Eyes with closed angle, history of angle closure glaucoma or with inadequate follow–up were excluded; eyes with iridocorneal apposition but open angle recess on UBM were included in the study. All eyes were on one to three IOP lowering drugs prior to uneventful phacoemulsification plus in the bag foldable IOL implantation performed by the same surgeon. In order to calculate the real postoperative IOP reduction , only 14 eyes–of 8 patients aged between 57 and 76 (mean 66) years– with postoperative IOP up to 20 mmHg without medication were fully re–evaluated 11 to 23 (mean 15) months after surgery.
Results: :
In 14 selected eyes untreated IOP was significantly (p< 0.001) reduced from 27 ± 7 (range 24–36) mmHg at first observation to 17 ± 3 (range 15–20) mmHg after phacoemulsification; the reduction was significantly correlated with preoperative IOP. Preoperative and postoperative ACD measurements by UBM were 1.90 ± 0.18 (range 1.74 – 2.10) mm and 3.59 ± 0.37(range 3.22– 4.05) mm respectively. Preoperative mean AW was 14 ± 5 (range 7–18) degrees and increased to 28 ± 4 (range19–35) degrees after phacoemulsification; plateau iris configuration was evident in 50% of eyes. Mean LT, AL and CCT were 4.9 ± 03 mm, 22.20 ± 0.6 mm and 543 ± 29 micron respectively.
Conclusions: :
In our limited series of eyes with narrow angle glaucoma and normalized untreated IOP after phacoemulsification, preoperative reduced ACD and AW, increased LT and short AL were similar to those reported in eyes with history of angle closure glaucoma. Eyes with narrow angle glaucoma and such biometric parameters will more likely achieve a major IOP reduction after phacoemulsification, due to increased ACD and AW.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • anterior segment • intraocular pressure