Effect of intraoperative factors on IOP reduction after phacoemulsification

Changes in Macular Thickness after Cataract Surgery in Patients with Open Angle Glaucoma

BACKGROUND

The purpose of this study was to examine the changes in IOP, total macular and RNFL, ganglion cell layer (GCL) thickness, and aqueous humour flare in open angle glaucoma (OAG) patients before and 6 months after cataract surgery.

METHODS

This was a prospective observational case-control age- and gender-matched study. Groups: 40 subjects in a controlled OAG (OAG_c) group, 20 subjects in an uncontrolled OAG (OAG_u) group, and 60 control group subjects.

EXAMINATION

complete ophthalmic evaluation, IOP measurement, anterior and posterior segment Optical Coherence Tomography (OCT), and laser flare photometry before and 6 months postoperatively.

RESULTS

Six months postoperatively IOP decreased in all groups. An increase in macular thickness was found postoperatively in all groups. Preoperative aqueous humour flare was higher in the OAG_c group than in the control group. After cataract surgery, aqueous humour flare was higher in the control group compared to the preoperative result.

CONCLUSIONS

Changes in IOP following cataract surgery were strongly negatively correlated with preoperative IOP. An increase in macular thickness was observed 6 months postoperatively in all groups. Aqueous humour flare did not differ in OAG_c and OAG_u groups pre- and postoperatively but significantly increased in the control group postoperatively.

Predictors of intraocular pressure reduction after femtosecond laser-assisted cataract surgery versus conventional phacoemulsification surgery: a prospective trial

PURPOSE

To evaluate the association between postoperative intraocular pressure (IOP) reduction and phacoemulsification parameters in patients who underwent both conventional phacoemulsification surgery (CPS) and femtosecond laser-assisted cataract surgery (FLACS).

METHODS

This was a prospective multicenter comparative study that enrolled 90 participants who underwent cataract surgery at the University of Maryland Medical System and the Wilmer Eye Institute. Patients underwent FLACS in one eye and CPS in the fellow eye. IOP was measured prior to surgery and monitored through six months postoperatively. Demographic, clinical, biometric, and intraoperative variables including cumulative dissipated energy (CDE), aspiration time, and phacoemulsification time were analyzed for any significant association with postoperative IOP. Postoperative IOP reduction was the primary outcome variable. A secondary goal of the study was to determine differences in postoperative IOP reduction between CPS and FLACS cohorts.

RESULTS

In total, 157 non-glaucomatous eyes were included. Using multivariable analysis, we found preoperative IOP to be consistently associated with postoperative IOP reduction in the entire cohort. At the 6-month follow-up visit, there was a 12.4% reduction in IOP (-2.2 ± 3.4 mm Hg) seen, with no statistically significant difference between FLACS and CPS (12.3% ± 19.4% vs 12.5% ± 19.3%, respectively, p = 0.32). FLACS reduced the CDE required for phacoemulsification (6.6 ± 4.4%-seconds vs 8.6 ± 6.9%-seconds, respectively, p < 0.05). CDE was a predictor of IOP response at 6 months, but subgroup analysis revealed that this trend was driven by seven eyes requiring high CDE, and for the majority of eyes, CDE did not influence the size of the decrease. The seven eyes experiencing highest CDE were less likely to show IOP reduction at 6 months.

CONCLUSION

Both FLACS and CPS resulted in similar and significant IOP reductions through 6 months after surgery. Preoperative IOP was significantly associated with IOP reduction, and CDE generally did not influence the size of the decrease.

Intraocular Pressure Changes Following Stand-Alone Phacoemulsification: An IRISɌ Registry Analysis

PURPOSE

To describe real-world intraocular pressure (IOP) changes following stand-alone cataract surgery by comparing postoperative IOP to phakic fellow eyes.

DESIGN

Retrospective clinical cohort study.

METHODS

A total of 1,334,868 patients (336,060 with glaucoma and 998,808 without glaucoma) in the IRIS® Registry (Intelligent Research in Sight) underwent stand-alone phacoemulsification from 1 January 2013 to 30 September 2019 with a fellow eye that had subsequent cataract surgery. Postoperative daily mean IOP was compared between surgical and control eyes from postoperative day 1 to 90. A generalized linear model determined when the postoperative daily mean IOP stabilized to calculate a final mean IOP, which was then compared to baseline IOP.

RESULTS

Postoperative daily mean IOP was initially greater for surgical than for control eyes because of an early postoperative IOP spike. By postoperative day 13, postoperative daily mean IOP was significantly lower for surgical than for control eyes every day through postoperative day 90 (P < .001). There was a mean (SD) decrease from baseline to final mean IOP of 1.55 (3.52) mm Hg or 7.79% for all surgical eyes, 1.91 (3.93) mm Hg or 8.89% for surgical eyes with glaucoma, and 1.37 (3.28) mm Hg or 7.24% for surgical eyes without glaucoma, respectively. There was a statistically significant decrease from baseline to the final mean IOP for all surgical eyes, surgical eyes without glaucoma, and all categories of pre-glaucoma and glaucoma (P < .0001 for all, excluding uveitic glaucoma [P = .0016]).

CONCLUSIONS

Eyes both with and without glaucoma that underwent stand-alone phacoemulsification had a significant decrease in IOP through the 90-day postoperative period compared to baseline and phakic fellow eyes.

Impact of Cataract Surgery on IOP and Ocular Structures in Normotensive Patients and Primary and Exfoliation Open-Angle Glaucoma Patients

Purpose

The aim of this study was to evaluate and compare the changes in Intraocular Pressure (IOP) and other ocular parameters: the Anterior Chamber Angle (ACA), Anterior Chamber Volume (ACV), and Anterior Chamber Depth (ACD) during phacoemulsification surgery in Greek patients with normotensive eyes and those with well-controlled Open-Angle Glaucoma (OAG). Additionally, parameters such as the Corneal Thickness (CCT), Axial Length (AL), Central Macular Thickness (CMT), and Retinal Nerve Fibre Layer (RNFL) were also examined.

Patients and Methods

This was a prospective observational case-control study that included 50 phakic eyes, 25 normotensive (Group 1), and 25 with OAG: 15 Primary Open-Angle Glaucoma (POAG) and 10 Exfoliation Glaucoma (EXG) (Group 2). Ophthalmic assessment included IOP measurements, ocular biometry, and anterior and posterior segment optical coherence tomography evaluation of the aforementioned ocular parameters, prior and 6 months after phacoemulsification surgery.

Results

At the 6 months post-operative review, a greater IOP reduction was recorded in eyes with OAG, in comparison to normotensive ones (5.3mmHg and 1.6 mmHg respectively). In addition, a significant but similar increase was recorded in the values of the ACA, ACV, and ACD of both groups between the pre- and the post-op period. Furthermore, the CCT and AL values remained unaltered. Finally, there was a non-statistically significant change in the mean CMT and the mean average RNFL of both groups.

Conclusion

Eyes with OAG tend to undergo a greater reduction in IOP post-phacoemulsification surgery, in comparison to normotensive eyes. This reduction may not be solely attributed to ocular anatomical changes after phacoemulsification surgery but may also be due to the remodeling of the trabecular meshwork and the ciliary body. This may be especially true in the case of OAG eyes, which already start off with a compromised trabecular endothelium prior to surgery.

Intraocular Pressure and Medication Burden With Cataract Surgery Alone, or Cataract Surgery Combined With Trabecular Bypass or Goniotomy

PRCIS

When compared with cataract surgery in glaucoma patients, trabecular micro-bypass and goniotomy resulted in a large decrease in the incidence of intraocular pressure (IOP) spikes, a modest effect on IOP, and a minimal effect on medication burden.

PURPOSE

To compare changes in IOP and ocular hypotensive medications in 3 surgical cohorts: cataract surgery, cataract surgery with trabecular micro-bypass (cataract/trabecular), and cataract surgery with goniotomy (cataract/goniotomy).

MATERIALS AND METHODS

We included 138 eyes diagnosed with open-angle glaucoma: (1) 84 eyes with cataract surgery alone, (2) 25 eyes with cataract/trabecular surgery, and (3) 29 eyes with cataract/goniotomy surgery. We compared the groups for postoperative IOP and the number of ocular hypotensive medications. We adjusted for preoperative IOP, and preoperative and postoperative number of ocular hypotensive medications. We defined an IOP spike as IOP ≥21 mm Hg and 10 mm Hg higher than preoperative on postoperative day 1.

RESULTS

All 3 surgeries showed a decrease in IOP (P≤0.004) and medication burden (P≤0.001) at 3 and 6 months postoperatively when compared with their own preoperative baselines. When compared with cataract surgery alone, cataract/trabecular and cataract/goniotomy had similar IOP lowering at 1 month postoperatively, and variable results at 3 and 6 months. The change in ocular hypotensive medications was not statistically different between the surgical groups at any postoperative visit. Cataract/trabecular and cataract/goniotomy decreased IOP on postoperative day 1, and had relative risk reduction of ~70% for IOP spikes (P≤0.001 for both).

CONCLUSION

Trabecular micro-bypass and goniotomy when added to cataract surgery resulted in a large decrease in IOP spikes, a modest effect on IOP, and a minimal effect on medication burden when compared with cataract surgery alone in glaucoma patients.

Predictors of intraocular pressure change after cataract surgery in patients with pseudoexfoliation glaucoma and in nonglaucomatous patients

Background/Aim. The cataract surgery in eyes with and without glaucoma results in the sustained intraocular pressure (IOP) reduction but it is still unknown which glaucomatous patients will achieve clinically significant reduction. The preoperative IOP and some ocular biometric parameters have been shown as potential predictors of the postoperative IOP reduction. The aim of our prospective intervention study was to evaluate that relationship in medically controlled patients with the pseudoexfoliation glaucoma (PXG) and in the nonglaucomatous patients. Methods. Thirty-one PXG patients (31 eyes) and 31 nonglaucomatous patients (31 eyes), all with clinically significant cataract, were enrolled. The preoperative IOP, anterior chamber depth (ACD), axial length (AL), lens thickness (LT), lens position (LP) [LP = ACD + 0.5 LT], relative lens position (RLP) [RLP = LP / AL] and the pressure-to-depth ratio (PD ratio) [PD ratio = preoperative IOP/preoperative ACD] were evaluated as potential predictors of the IOP change in the 6th postoperative month. Results. In the 6th postoperative month, in the PXG group, the IOP reduction was -3.23 ? 3.41 mmHg (-17.67 ? 16.86%) from the preoperative value of 16.27 ? 3.08 mmHg and in the control group, the reduction was -2.26 ? 1.71 mmHg (-15.06 ? 10.93%) from the preoperative value of 14.53 ? 2.04 mmHg. In the PXG group, the significant predictors of the absolute and the percentage IOP reduction were the preoperative IOP, AL, and PD ratio. In the same group, RLP was shown as a significant predictor of absolute change in the IOP in multi-variate analysis, and the percentage IOP change in both the univariate and the multivariate analyses. In the control group, the preoperative IOP and the PD ratio were the only significant parameters that could predict absolute change in the postoperative IOP. Conclusion. The cataract surgery leads to the IOP reduction both in the PXG and nonglaucomatous eye. Predictors monitored in this study are widely available and simply calculable parameters that can be potentially used in managing glaucoma.

The Clinical Guiding Role of the Distribution of Corneal Nerves in the Selection of Incision for Penetrating Corneal Surgery in Canines

The cornea is one of the regions with the highest density of nerve terminals in the animal body and it bears such functions as nourishing the cornea and maintaining corneal sensation. In veterinary clinical practice, the corneoscleral limbus incision is frequently applied in cataract surgery, peripheral iridectomy, and other procedures for glaucoma. Inevitably, it would cause damage to the nerve roots that enter the cornea from the corneal limbus, thus inducing a series of complications. In this paper, the in vitro cornea (39 corneas from 23 canines, with ages ranging from 8 months old to 3 years old, including 12 male canines and 11 female canines) was divided into 6 zones, and the whole cornea was stained with gold chloride. After staining, corneal nerves formed neural networks at different levels of cornea. There was no significant difference in the number of nerve roots at the corneoscleral limbus between different zones (F = 1.983, p = 0.082), and the nerve roots at the corneoscleral limbus (mean value, 24.43; 95% CI, 23.43-25.42) were evenly distributed. Additionally, there was no significant difference in the number of corneal nerve roots between male and female canines (p = 0.143). There was also no significant difference in the number of corneal nerve roots between adult canines and puppies (p = 0.324). The results of the above analysis will provide a reasonable anatomical basis for selecting the incision location and orientation of penetrating surgery for the canine cornea in veterinary practice.

Changes in ocular morphology after cataract surgery in open angle glaucoma patients

The purpose of this study was to evaluate intraocular pressure (IOP) pre- and postoperatively, together with anterior chamber angle (ACA) parameters and biometrical results in cataract patients with or without open angle glaucoma (OAG). The prospective observational case-control study included 15 eyes with cataract and OAG in the glaucoma group and 25 eyes with only cataract in control group. Examination included full ophthalmic evaluation, IOP, ocular biometry and anterior segment optical coherence tomography measuring ACA pre- and 6 months postoperatively. OAG patients had a larger absolute IOP reduction compared to control group. Anterior chamber depth (ACD) and ACA width significantly increased in both groups. The OAG group had a tendency of narrower ACA preoperatively, but overall ACA parameters did not differ in either group pre- and postoperatively. The ACD change after surgery correlated with ACA parameters in the control group, but not in OAG group. Axial length was shorter postoperatively in the control group, but remained similar in the OAG group. Absolute IOP reduction was more pronounced in cataract patients with OAG than in cataract patients without glaucoma. ACD and ACA postoperatively increased in both groups and AL shortening was observed in non-OAG in cataract group.

Intraocular Pressure Changes after Cataract Surgery in Patients with and without Glaucoma: An Informatics-Based Approach

PURPOSE

To evaluate changes in intraocular pressure (IOP) after cataract surgery among patients with or without glaucoma using automated extraction of data from electronic health records (EHRs).

DESIGN

Retrospective cohort study.

PARTICIPANTS

Adults who underwent standalone cataract surgery at a single academic center from 2009-2018.

METHODS

Patient information was identified from procedure and billing codes, demographic tables, medication orders, clinical notes, and eye examination fields in the EHR. A previously validated natural language processing pipeline was used to identify laterality of cataract surgery from operative notes and laterality of eye medications from medication orders. Cox proportional hazards modeling evaluated factors associated with the main outcome of sustained postoperative IOP reduction.

MAIN OUTCOME MEASURES

Sustained post-cataract surgery IOP reduction, measured at 14 months or the last follow-up while using equal or fewer glaucoma medications compared with baseline and without additional glaucoma laser or surgery on the operative eye.

RESULTS

The median follow-up for 7574 eyes of 4883 patients who underwent cataract surgery was 244 days. The mean preoperative IOP for all patients was 15.2 mmHg (standard deviation [SD], 3.4 mmHg), which decreased to 14.2 mmHg (SD, 3.0 mmHg) at 12 months after surgery. Patients with IOP of 21.0 mmHg or more showed mean postoperative IOP reduction ranging from -6.2 to -6.9 mmHg. Cataract surgery was more likely to yield sustained IOP reduction for patients with primary open-angle glaucoma (hazard ratio [HR], 1.19; 95% confidence interval, 1.05-1.36) or narrow angles or angle closure (HR, 1.21; 95% confidence interval, 1.08-1.34) compared with patients without glaucoma. Those with a higher baseline IOP were more likely to achieve postoperative IOP reduction (HR, 1.06 per 1-mmHg increase in baseline IOP; 95% confidence interval, 1.05-1.07).

CONCLUSIONS

Our results suggest that patients with primary open-angle glaucoma or with narrow angles or chronic angle closure were more likely to achieve sustained IOP reduction after cataract surgery. Patients with higher baseline IOP had increasingly higher odds of achieving reduction in IOP. This evidence demonstrates the potential usefulness of a pipeline for automated extraction of ophthalmic surgical outcomes from EHR to answer key clinical questions on a large scale.

Cyclodialysis ab externo with implantation of a collagen implant in surgical management of glaucoma

Glaucoma is one of the main causes of irreversible blindness in the Russian Federation and it is the leading cause of visual impairments among working age population. The primary goal of glaucoma therapy is to preserve the visual function, which is mainly achieved through persistent normalization of IOP by instillation of hypotensive drugs, laser therapy and/or surgery/ In this clinical study safety and efficacy of a glaucoma surgical technique implying valve cyclodialysis ab externo with implantation of a non-absorbable collagen implant (NACI) (Xenoplast, Dubna-Biofarm, Russia) in the supraciliary space were evaluated. All patients exhibited moderate and severe primary open-angle glaucoma (POAG). The efficacy assessment criterias were intraocular pressure (IOP) dynamics, use of hypotensive medications, need for repeat surgical intervention and complications. A total of 26 patients (26 eyes) were operated upon and under observation. Twelve months after surgery, 34% IOP decrease from the baseline level was observed: from 29.5 ± 6.8 to 18.8 ± 4.3 mmHg. The amount of hypotensive medications used reduced from 2.8 ± 0.9 to 0.6 ± 0.9. Applying the criteria recommended by the World Glaucoma Association, complete success was registered in 73.1% of patients and partial success — in 26.9% patients. No surgery ended in a failure through the follow-up period. Post-operatively, one patient developed hyphema, 2 patients had some blood elements in aqueous humor and 1 patient had shallow anterior chamber (AC). The suggested surgical technique proved to be an efficient and safe way to decrease IOP and reduce the number of hypotensive medications and had a minimal number of complications associated with the surgery, therefore it can be recommended as a method of choice in patients with advanced stage POAG.

Intraocular Pressure and Anterior Segment Morphometry Changes after Uneventful Phacoemulsification in Type 2 Diabetic and Nondiabetic Patients

Purpose

To compare intraocular pressure (IOP) and anterior segment (AS) morphometry changes after uneventful phacoemulsification between nonglaucomatous eyes with open-angles from patients with and without type 2 diabetes mellitus (DM) and determine which factors may predict greater IOP-lowering effect.

Methods

Forty-five diabetic (45 eyes) and 44 (44 eyes) age- and sex-matched non-DM patients with age-related cataract were enrolled in this prospective observational study. Goldmann applanation tonometry and AS Scheimpflug tomography (Pentacam® HR) were performed preoperatively and at 1- and 6-month follow-up. Linear regression analysis was performed to evaluate the clinical variables related to postoperative IOP changes at 6 months.

Results

There was a significant postoperative IOP reduction 6 months after surgery (p < 0.001) by an average of 2.9 ± 2.9 mmHg (15.5%) and 2.4 ± 2.8 mmHg (13.0%) in the DM group and non-DM groups (p = 0.410), respectively. All AS parameters (anterior chamber depth, volume, and angle) increased significantly postoperatively (p < 0.001). Multivariate linear regression analysis showed that higher preoperative IOP was significantly associated with IOP reduction at 6-month follow-up (p < 0.05).

Conclusion

Nonglaucomatous eyes with open-angles from both type 2 diabetic and nondiabetic patients experienced similar AS changes and IOP reductions following uneventful phacoemulsification, and this IOP-lowering effect was strongly correlated with preoperative IOP.

How to Predict Intraocular Pressure Reduction after Cataract Surgery? A Prospective Study

Purpose/Aim: To evaluate the best formula to predict intraocular pressure (IOP) reduction after cataract surgery. Materials and methods: In this prospective longitudinal study, we included consecutive patients with or without glaucoma, either with open or with narrow angles but without peripheral anterior synechiae, who underwent phacoemulsification. Clinical factors and anterior segment parameters measured with optical biometry and optical coherence tomography were evaluated as preoperative predictors for IOP reduction at 6 months postoperatively. To find the best combinations of predictors, model selection was conducted using least absolute selection and shrinkage operator regression with cross-validation. Results: A total of 156 eyes from 109 patients were enrolled. The mean age of the patients was 74.89 (±8.54) years and the average preoperative IOP was 15.6 (±3.68) mmHg with 0.7 (range 0-4) glaucoma medications. The mean IOP reduction after phaco was 3.1 (±2.49) mmHg at postoperative month 6. After multivariate analysis, preoperative IOP (β = 0.49 [0.4-0.59] P < .0001), gonioscopy score (β = -0.14 [-0.23 to -0.06] P = .0001), anterior chamber depth (β = -0.85 [-1.64 to -0.07] P = 0.033), lens thickness (LT) (β = 0.87 [0.12-1.62] P = .024), and angle open distance 750 (β = -2.2 [-3.96 to -0.44] P = 0.014) were associated with IOP reduction. The best formula to correlate with IOP reduction was -4.76 + (0.46 × preoperative IOP) - (0.42 × LT) - (0.1 × gonioscopy score) - (0.66 × glaucoma status). Conclusion: Different formulas were developed and were able to improve the predictive value of the preoperative IOP. When used in combination, these formulas may help the clinician to know how much IOP reduction to expect after cataract surgery at 6 months postoperatively.

Effect of phacoemulsification on facility of outflow

Purpose

Phacoemulsification has been shown to reduce intraocular pressure (IOP). The mechanism of action is thought to be via increased trabecular outflow facility. However, studies on the relationship between phacoemulsification and outflow facility have been inconsistent. This study intended to examine the change in electronic Schiotz tonographic outflow facility (TOF) and IOP measurements following phacoemulsification.

Methods

Patients who were due to undergo a standard clear corneal incision phacoemulsification with intraocular lens (IOL) implantation, at St Thomas’ Hospital, were invited to participate in this study. IOP was measured using Goldmann’s applanation tonometer, and TOF was measured by electronic Schiotz tonography at baseline and at 3, 6 and 12 months postoperatively.

Results

Forty-one patients were recruited. Tonography data for 27 patients were reliable and available at all time points. Eleven cases had primary open angle glaucoma and cataract, while 16 patients had cataract only. Mean IOP reduced at every time point postoperatively significantly compared with baseline. TOF improved significantly after cataract extraction at all time points (baseline of 0.14±0.06 vs 0.18±0.09 at 3 months, P=0.02 and 0.20±0.09 at 6 months, P=0.003, 0.17±0.07 µL/min mmHg at 12 months, P=0.04). Five contralateral eyes of patients with cataracts only who did not have any intraocular surgery during the follow-up period were used as comparison. Their IOP and TOF did not change significantly at any postoperative visits.

Conclusion

This is the first study using electronic Schiotz tonography with documented anterior chamber depth and gonioscopy after modern cataract surgery (CS) with phacoemulsification and IOL implantation. We demonstrated that phacoemulsification increases TOF and this fully accounts for the IOP reduction following CS.

ISTCRN registration number

ISRCTN04247738.

Microinvasive Glaucoma Surgery: An Evidence-Based Assessment

Introduction

The advent of Microinvasive Glaucoma Surgery (MIGS) offers a novel approach in the treatment of glaucoma with the number of procedures developing at an exciting pace.

Areas Covered

MIGS procedures aim to lower intraocular pressure (IOP) via four mechanisms: (1) increasing trabecular outflow, (2) increasing outflow via suprachoroidal shunts, (3) reducing aqueous production, and (4) subconjunctival filtration. A comprehensive search for published studies for each Microinvasive Glaucoma Surgery (MIGS) device or procedure was undertaken using the electronic database PubMed. Search terms included 'minimally invasive glaucoma surgery', 'microincisional glaucoma surgery', and 'microinvasive glaucoma surgery'. A manual search for each device or procedure was also performed. After review, randomized control trials and prospective studies were preferentially included.

Expert Opinion

These procedures offer several benefits: an improved safety profile allowing for intervention in earlier stages of glaucoma, combination with cataract surgery, and decreased dependence on patient compliance with topical agents. Established MIGS procedures have proven efficacy and more recent devices and procedures show promising results. Despite this, further study is needed to assess the long term IOP-lowering effectiveness of these procedures. Particularly, rigorous study with more randomized control trials and head-to-head comparisons would allow for better informed clinical and surgical decision-making. MIGS offers new solutions for glaucoma treatment.