Nasal trabeculo-ciliary angle and relative lens vault as predictors for intraocular pressure reduction following phacoemulsification

Purpose To evaluate quantitative relationships between biometric measurements and expected intraocular pressure reduction following phacoemulsification. Design A prospective, comparative clinical study. Methods Forty nine candidates for phacoemulsification were included. Intraocular pressure was measured preoperatively and after 7 and 30 days. Ocular biometrics were measured using optical biometry and ultrasound biomicroscopy preoperatively and 1 month postoperatively. Results Patients were sub-grouped into open-angle glaucoma (12 eyes), angle-closure glaucoma (18 eyes), and cataract-only groups (19 eyes). The mean intraocular pressure reduction was −1.67 ± 2.73, −13.11 ± 7.98, and −7.50 ± 3.58 mmHg in the cataract-only, angle-closure glaucoma, and open-angle glaucoma groups ( p = 0.001). The delta-intraocular pressure at day 7 showed positive correlations with lens vault and relative-lens vault ( p = 0.005 and 0.001). It showed negative correlations with lens position, relative-lens position, anterior chamber depth, aqueous depth, and nasal and temporal angles in addition to lens thickness, anterior vault, nasal trabeculo-ciliary angle, and temporal-trabeculo-ciliary angle at the end of the follow-up period. Regression analysis revealed significant associations between preoperative intraocular pressure and both nasal-trabeculo-ciliary angle and anterior vault ( p = 0.038 and 0.019) and delta-intraocular pressure and both nasal-trabeculo-ciliary angle and relative-lens vault ( p = 0.001 and ≤0.001) with an area under the curve of 0.71 for relative-lens vault. For every degree decrease in nasal-trabeculo-ciliary angle, there was an expected 0.33 mmHg intraocular pressure reduction with no expected change if nasal-trabeculo-ciliary angle decreased to <22°. Conclusions The relationship between anterior-segment-biometrics could determine intraocular pressure behavior after phacoemulsification. The preoperative nasal-trabeculo-ciliary angle and relative-lens vault could be significant predictors for postoperative intraocular pressure reduction.

Effects of regular exercise on intraocular pressure

Background Exercise may potentially provide an adjunctive measure to help control intraocular pressure in glaucoma patients. However, currently, there is still no substantial evidence that regular exercise can produce a prolonged effect of intraocular pressure reduction. We aim to determine the effects of regular exercise on intraocular pressure in healthy individuals. Methods We conducted a prospective, interventional study at the University of Malaya Medical Centre. Our subjects consist of 45 healthy participants in the intervention arm, and 38 healthy control participants who were age- and gender-matched. The intervention arm was enrolled into a supervised exercise programme for a 6-week period, where controls were asked to continue their usual daily lifestyle. The intervention consists of three sessions every week, which focused on aerobic exercise and strength training. Results Baseline intraocular pressure was measured, and then remeasured again at the end of 6 weeks of exercise conditioning. In the intervention group, there was a reduction of baseline intraocular pressure from pre-intervention mean intraocular pressure of 15.55 ± 2.63 mmHg, down to 13.36 ± 3.16 mmHg at 6 weeks, a statistically significant reduction of −2.18 ± 2.25 mmHg ( p < 0.001) post-intervention. On the other hand, the control group recorded a non-statistically significant mean increase of 0.63 ± 2.47 mmHg ( p = 0.123) at 6 weeks. Conclusions Our study concluded that regular exercise results in a significant intraocular pressure reduction in healthy individuals.

Correlation between intraocular pressure reduction and anterior chamber aqueous flare after micropulse transscleral cyclophotocoagulation

Background Micropulse transscleral cyclophotocoagulation (MP-CPC) is a technique that has been approved in recent years to treat glaucoma. MP-CPC causes anterior chamber inflammation; a relationship with reduced intraocular pressure (IOP) has not been reported. Therefore, we analyzed the correlation between IOP and anterior chamber aqueous flare after MP-CPC. Methods This retrospective study included 37 eyes of 37 patients who underwent MP-CPC between November 2018 and October 2020. IOP and flare values were measured at 1, 4, and 12 weeks after MP-CPC. Correlations were assessed between the percentage IOP reduction and flare elevation by calculating Spearman’s rank correlation coefficient. Results The percentage IOP reduction at 1 week after surgery was correlated with the flare elevation at 1 week after surgery (ρ = 0.47, P = 0.006). The percentage IOP reduction at 12 weeks after surgery was correlated with the flare elevation at 4 weeks after surgery (ρ = 0.53, P = 0.006). Conclusions A short-term correlation was implied between reduced IOP and flare elevation after MP-CPC.

PRESERFLO MicroShunt

The PRESERFLO® MicroShunt (Santen Pharmaceutical Co. Ltd., Osaka, Japan), formerly called the InnFocus MicroShunt®, is a trans-scleral device that shunts aqueous humour from the anterior chamber to a filtering bleb under the conjunctiva and Tenon’s capsule. Manufactured from an inert biocompatible material called poly(styrene-block-isobutylene-block-styrene), or ‘SIBS’, the device elicits minimal foreign body reaction and inflammation; potentially reducing the risk of bleb-related fibrosis and failure. The MicroShunt is 8.5 mm long with a 70 μm lumen and is designed to minimize hypotony based on the Hagen–Poiseuille equation. Inserted via an ab-externo approach, the MicroShunt eliminates the need for creation of a scleral flap, sclerostomy, iridectomy, scleral flap suturing and postoperative suture lysis. Clinical trials show promising results with the MicroShunt achieving intraocular pressure reduction approaching that of trabeculectomy, the current gold standard for treating refractory glaucoma.