Benefits of Laser Peripheral Iridotomy (LPI) for Narrow Angle Before Cataract Surgery

Benefits of Laser Peripheral Iridotomy (LPI) for Narrow Angle Before Cataract Surgery

The below papers give two reasons why it is likely better to have a Laser Peripheral Iridotomy (LPI) for Narrow Angle before Cataract Surgery. While Cataract extraction will get rid of the narrow angle, in many cases it is better to do the LPI before surgery. The risks, pain of LPI are minimal.

Patients with narrow angles have lower anterior chamber depths (ACD). The lower ACD gives the surgeon less room between the cornea (and the inner layer of the cornea where the precious endothelial cells live) and the surface of the cataract. LPI increases a patient’s anterior chamber depth (ACD). If the ACD is below 2.5, we know the risks of cataract surgery are higher. We presented a poster at Harvard showing this as well.

Having a more shallow chamber or lower ACD, also increase the loss of endothelial cells after cataract surgery.

These two papers support the recommendation to do an LPI before cataract surgery if the ACD is less than 2.5mm in most patients.

Sandra Lora Cremers, MD, FACS

Journal of Ophthalmology
Volume 2015 (2015), Article ID 210716, 7 pages
http://dx.doi.org/10.1155/2015/210716

Clinical Study

Endothelial Cell Loss after Phacoemulsification according to Different Anterior Chamber Depths

Hyung Bin Hwang, Byul Lyu, Hye Bin Yim, and Na Young Lee

Department of Ophthalmology, Incheon St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, 222 Banpo-daero, Seocho-gu, Seoul 137-701, Republic of Korea

Received 4 April 2015; Accepted 19 August 2015

Academic Editor: Lisa Toto

Copyright © 2015 Hyung Bin Hwang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Purpose. To compare the loss of corneal endothelial cells after phacoemulsification according to different anterior chamber depths (ACDs). Methods. We conducted a prospective study on 135 eyes with senile cataracts. Eyes with nuclear density grades of 2 to 4 were divided into three groups according to ACD: ACD I, 1.5 < ACD ≤ 2.5 mm; ACD II, 2.5 < ACD ≤ 3.5 mm; or ACD III, 3.5 < ACD ≤ 4.5 mm. Intraoperative mean cumulative dissipated energy (CDE) was measured. Clinical examinations included central corneal thickness (CCT) and endothelial cell count (ECC) preoperatively and 2 months postoperatively. Results. There were no significant differences in CDE among the ACD groups (). Endothelial cell loss was significantly higher in ACD I than in ACD III in grades 3 and 4 cataract density groups 2 months after phacoemulsification (). There were also more changes in CCT in all of the cataract density groups in the ACD I group compared to the ACD II and III groups 2 months postoperatively, but the difference was not statistically significant. Conclusions. Eyes with shallow ACDs, especially those with relatively hard cataract densities, can be vulnerable to more corneal endothelial cell loss in phacoemulsification surgery.

Abstract

Purpose: : To assess if smaller anterior chamber depth (ACD) is a risk factor for intra-operative complications during cataract surgery.

Methods: : Data from an electronic cataract database was analysed for 8891 eyes at the Queen Alexandra Hospital, Portsmouth, UK. All eyes which had a central ACD measured were included in the study. All intra-operative complications and issues (posterior capsule rupture/dialysis, capsulorexis tears, iris prolapse, corneal oedema and descemet tears) were recorded. Complication rates were compared between ≤ 2.5mm and > 2.5mm ACD groups. Chi square (2- tailed with Yates correction) were used to calculate P values and odds ratios (OR) with 95% confidence intervals.

Results: : 1138 eyes were identified as having an ACD ≤ 2.5 mm and 7753 had an ACD >2.5 mm. The overall complication rate was 3.56%. Complications were seen significantly more in the ACD ≤2.5 mm group as compared to the ACD >2.5 mm group, 54(4.75%) versus 263(3.40%) with an odds ratio of 1.42 (P=0.026, 95% CI = 1.05 -1.92). Posterior capsule rupture/zonular dialysis (+/- vitreous loss) was seen in 23 (2.0%) of the eyes with an ACD ≤ 2.5 mm compared to 95 (1.2%) in the > 2.5 mm ACD group (OR= 2.060, P=0.036, 95% CI = 1.64 -2.60) with an over 2 fold risk. A shallow anterior chamber with vitreous bulge was also significantly more common in the ≤ 2.5mm ACD group i.e., 51 (4.48%) versus 93 (1.2%) in the >2.5 mm group (OR= 3.386, P<0.0001, 95%CI = 2.70-5.50).

Conclusions: : Patients with anterior chamber depths ≤ 2.5mm are significantlymore at risk of developing complications during cataract surgery. ACD should be considered as a factor in risk stratification preoperatively.