Changes in the intraocular pressure of fellow untreated eyes following uncomplicated trabeculectomy

Short-Term Effect of Micropulse Transscleral Laser Therapy on Intraocular Pressure in Untreated Fellow Eyes of Glaucoma Patients: Preliminary Results

It has been observed that an intraocular pressure (IOP) altering intervention in one eye is followed by a consensual response in the untreated fellow eye. The underlying mechanisms remain unclear. Involvement of neuronal, cytokine, and hormonal regulation of aqueous humor dynamics, as well as improved treatment adherence or systemic absorption of topically administered medical compounds, have been suggested. Our aim was to investigate the short-term effects of unilateral micropulse transscleral laser therapy on IOP in the fellow eye. All medical records of glaucoma patients who underwent micropulse transscleral laser therapy in a tertiary referral center between May 2019 and February 2023 were collected and analyzed. We found a significant reduction in IOP in the treated eyes, indicating successful treatment. In the fellow eyes, despite not having changed any of the pharmacological IOP-reducing therapies, a significant reduction in IOP from 17.0 ± 5.1 mmHg to 13.5 ± 4.4 mmHg (p < 0.01) was observed. This reduction was, however, short-term and reached statistical significance on the first postoperative day only. Our findings support the concept of consensual inter-eye responses to unilateral IOP changes. Further research is warranted to elucidate the mechanisms underlying this phenomenon.

Intraocular Pressure Changes in the Contralateral Eye After Glaucoma Surgery

PRCIS

Glaucoma surgery in 1 eye can result in significant intraocular pressure (IOP) elevation in the fellow eye in a significant percentage of subjects. This effect is more pronounced following glaucoma drainage device implantation and in subjects developing postoperative hypotony in the first eye.

PURPOSE

The aim was to investigate the course and magnitude of IOP changes in contralateral eyes following glaucoma surgery.

PATIENTS AND METHODS

We studied 131 glaucoma patients undergoing surgery. IOP changes in fellow eyes and the number of glaucoma medications were recorded for 6 months. Both normal and glaucomatous fellow eyes were included. Patients on preoperative acetazolamide were analyzed separately. IOP change ≥4 mm Hg or 20% increase from baseline values was considered significant.

RESULTS

Baseline IOP in fellow eyes was 13.1±3.3 mm Hg which increased significantly at all-time points with a peak at 1 week (mean increase: 3.1±3.2 mm Hg) gradually decreasing up to 6 months (mean increase 0.9±2.1 mm Hg). The number of fellow eyes with clinically significant IOP elevation at 1 day, 1 week, and 1, 3. and 6 months was 47, 76, 47, 31, and 37 showing mean IOP rise of 4.5±2.3 (38.5%), 5.4±1.8 (48.5%), 4.8±1.6 (44.2%), 3.7±1.3 (36.5%), and 3.2±1.3 (32.6%) mm Hg, respectively. Medications were added to 18 fellow eyes (including 10 initially "normal" eyes) while 7 other fellow eyes required surgery.Significant IOP elevation in fellow eyes was associated with tube shunt surgery (P<0.008 at all-time points), a diagnosis of glaucoma following cataract surgery, IOP ≤5 mm Hg on the first postoperative day (P=0.002) and use of preoperative acetazolamide.

CONCLUSION

Glaucoma surgery was associated with IOP elevation in fellow eyes in a significant number of subjects and suggests that IOP in the unoperated eye should also be checked at postoperative visits.

Inter-eye relationship of intraocular pressure change after unilateral trabeculectomy, filtering canaloplasty, or PreserFlo™ microshunt implantation

PURPOSE

This study assesses short-term intraocular pressure (IOP) change in the fellow eye of glaucoma patients after mitomycin C-augmented trabeculectomy, filtering canaloplasty, or PreserFlo™ microshunt implantation in the treated eye.

MATERIALS AND METHODS

Retrospective chart review of 235 glaucoma patients (235 eyes) was performed. Patients underwent initial trabeculectomy (187 patients), filtering canaloplasty (25 patients), or PreserFlo™ microshunt implantation (23 patients) in one eye, while the fellow eye was naïve to any previous glaucoma surgery. IOP was evaluated before and on the 1st and 2nd days and at 1 week after surgery. Main outcome measure was IOP change in the fellow eye. Secondary outcomes were proportion of clinically significant IOP elevation in the fellow eye and evaluation of potential risk factors associated with postoperative IOP fluctuation.

RESULTS

IOP in the fellow eye at 1 week after trabeculectomy was statistically significantly lower than preoperatively (p < 0.0001), while the IOP did not change significantly in the fellow eyes in filtering canaloplasty or PreserFlo groups. The higher the preoperative IOP was in the fellow eye, the larger was the intraocular pressure-lowering effect at 1 week after trabeculectomy (p < 0.0001). A clinically significant IOP elevation was noted in 14.2%, 9.5%, and 5% of fellow eyes after trabeculectomy, filtering canaloplasty, or PreserFlo™ microshunt implantation, respectively.

CONCLUSIONS

This study shows an IOP-lowering effect in the fellow eye of glaucoma patients after trabeculectomy. Significant IOP rise might occur in the fellow eye of some glaucoma patients after different types of glaucoma surgery.

New approaches to selective laser trabeculoplasty

Selective laser trabeculoplasty (SLT) is the “golden standard” of laser glaucoma surgery. Its efficacy can be compared to pharmacological therapy, while in some cases its advantages may even lead to a more stable hypotensive effect. SLT may be used as a primary treatment for primary open-angle glaucoma patients and patients with ocular hypertension, while also considered safe and effective in cases when a repeat procedure is required. SLT may potentially decrease the demand for antiglaucoma drugs, improve patient’s response to treatment, make the treatment more comfortable and overall increase the patient’s quality of life. New modifications of standard laser treatment procedures have been emerging lately. This article summarizes scientific data on the efficacy and safety of the new generation of laser trabeculoplasty. It specifies the charateristics of micropulse laser trabeculoplasty (MLT), pattern-scanning trabeculoplasty (PLT) and titaniumsapphire laser trabeculoplasty (TSLT) and recounts the latest research dedicated to them.

Selective laser trabeculoplasty in pseudophakic and phakic eyes: a prospective study

AIM

To compare the efficacy of selective laser trabeculoplasty (SLT) in replacing medical therapy in pseudophakic and phakic eyes.

METHODS

Subgroup of a prospective randomized clinical trial including patients with primary open angle glaucoma or ocular hypertension controlled with medication. Of 38 pseudophakic eyes were matched with 38 phakic eyes. SLT was offered as a way to decrease medication while maintaining the same low eye pressure. SLT was performed over 360°, at 3ns, spotsize 400 µm, 100 spots. Data [intraocular pressure (IOP), number of medications needed] were measured at 1h, 1wk, 1, 3, 6 and 12mo. An independent-samples t-test was performed to compare baseline characteristics of the phakic and the pseudophakic group and differences in evolution of mean IOP and number of used medications. Chi-squared analysis was performed to investigate proportions of fast, slow and non-responders.

RESULTS

The mean IOP measurement was 13.00± 2.88 mm Hg in the phakic group (38 eyes) and 13.51±3.06 mm Hg in the pseudophakic group (38 eyes) (P>0.05). This changed little after SLT and IOP lowering effect was comparable between the two groups. Main aim however was to lower the amount of medication needed. In the phakic group medication lowered from 1.29±0.62 at baseline, to 0.15±0.46 after 12mo; a reduction of 88.37%. In the pseudophakic group, used medication changed from 1.71±1.04, to 0.41±0.61; a 76.02% reduction. The differences were not statistically significant at any time point (P>0.05). IOP lowering occurred slightly faster in the pseudophakic group (50% of patients after one week) than in the phakic group (68% of patients after more than 4wk). The difference was not significant (P>0.05).

CONCLUSION

IOP lowering effect of SLT is comparable between phakic and pseudophakic eyes.

Change in Intraocular Pressure in the Fellow Eye After Glaucoma Surgery in 1 Eye

PURPOSE

To measure the change in intraocular pressure (IOP) of the fellow eye after glaucoma surgery in 1 eye.

PATIENTS AND METHODS

In this prospective interventional study, 71 patients with primary and secondary glaucoma, undergoing glaucoma surgery in 1 eye were included. The IOP in the fellow eye following glaucoma surgery in 1 eye from the first postoperative week till 6 months following surgery was studied. Both normal and glaucomatous fellow eyes were included. IOP change from preoperative IOP levels in the fellow eye was analyzed. Patients treated with acetazolamide preoperatively were analyzed separately.

RESULTS

The mean baseline IOP of the operated and fellow eyes was 28.14±9.4 and 16.5±6.1 mm Hg, respectively. IOP of fellow eyes significantly increased compared with baseline at all timepoints (P<0.001), with a maximum rise 6 weeks postoperatively (4.8±3.3 mm Hg). There was no significant difference in the consensual rise between glaucomatous and nonglaucomatous fellow eyes, or between patients treated with or without acetazolamide before surgery. Regression analysis showed no baseline factor associated with the rise in IOP. By the sixth postoperative month, 24 patients required surgery or needed an increase in medications in the fellow eye for IOP control.

CONCLUSIONS

Glaucoma surgery in eye is associated with a rise in IOP of the fellow eye, regardless of whether the fellow eye is normal or glaucomatous, or had been previously treated with acetazolamide. Fellow eyes of all patients scheduled for glaucoma surgery require careful monitoring of the IOP.

Consensual ophthalmotonic reaction in Chinese patients following augmented trabeculectomy or ExPRESS shunt implantation

INTRODUCTION

Consensual ophthalmotonic reaction (COR) was first described in 1924. Studies following monocular application of glaucoma drops and laser trabeculoplasty showed a drop in fellow eye intraocular pressure (IOP). However, studies following monocular surgery showed heterogeneous results. The purpose of this study was to investigate the COR in Chinese patients who have received monocular filtration surgery.

METHODS

A noncomparative retrospective study of 65 eyes undergoing filtration surgery in Queen Mary Hospital was conducted. The IOP was obtained at baseline and postoperative days 1, 3, 7 and 14. Patient's age, sex, type of glaucoma and surgery, preoperative medications, postoperative bleb status, and number of interventions were tabulated. The postoperative IOP measurements over both eyes were obtained, and the readings were averaged to decrease the chances of extreme readings being a one-off event and allow for regression to the mean bias.

RESULTS

COR was observed in the unoperated fellow eye. The mean preoperative IOP and averaged postoperative IOP were 17.2 ± 5.2 mm Hg and 20.1 ± 8.9 mm Hg, respectively (P < 0.04). All medications were continued in the fellow eye or even stepped up. Twenty-three percent of patients demonstrated fellow eye IOP rise >30% from baseline, while none showed IOP drop >30% from baseline.

DISCUSSION

Following monocular penetrating filtration surgery, our Chinese population demonstrated a significant fellow eye IOP increase in the early postoperative period. We should bear in mind the influence of COR and take care to measure the fellow eye IOP following monocular surgery.

Where does selective laser trabeculoplasty stand now? A review

Background

Chronic treatment of glaucoma can present a challenge in patients who lack the means and/or the discipline to use daily glaucoma medication. We wondered if selective laser trabeculoplasty (SLT) could be a useful alternative.

Methods

Inclusion criteria: controlled trials comparing efficacy of SLT in adult patients with any form of open angle glaucoma or ocular hypertension and case reports on side effects of SLT. Two recent meta-analyses identified eight randomized clinical trials (RCTs) comparing the effect of SLT with medication (prostaglandin analogs) and with argon laser trabeculoplasty (ALT). We took these eight RCTs as reference base and calculated their success rates where they were not given. Other articles were added to elaborate on technique and side effects.

Results

Mean intraocular pressure (IOP) reduction after SLT was 3.8–8.0 mmHg after 6 months to 1 year. Mean success rate of SLT at 6 months to 1 year is 55–82 %. Higher IOP before laser predicts a higher IOP-lowering effect. In terms of mean IOP reduction, reduction in number of medications and treatment success, the effect of SLT was found to show no clinically relevant difference from that of contemporary medication (prostaglandin analogs) and from ALT.

Conclusions

The evidence indicates that SLT is an efficacious primary or adjunctive therapy for treating glaucoma.

INTRA-SCLERAL PARATHALAMUS IMPLANT: EFFICACY AND SAFETY IN RABBIT EYES

PURPOSE

A variety of anti-glaucomatous shunt designs have been proposed so far. This study evaluates the feasibility of a novel shunt design, the intra-scleral parathalamus implant (IPI), in a rabbit eye model.

METHODS

Ten healthy albino rabbits were included. Measurements of the IOP, using TonoPenXL, as well as ocular rigidity (OR) and aqueous outflow facility (AO), using a previously described methodology, were performed in both eyes of each animal. Subsequently, the IPI was implanted at the left eye of all animals whereas the right eye served as control. Measurements of IOP were repeated at weekly intervals for 2 months postoperatively whereas measurements of OR and AO were repeated at the 1st and 2nd postoperative week.

RESULTS

The IOP decreased significantly whereas the AO increased significantly postoperatively at the operated eyes. A significant postoperative decrease in OR was also recorded at the operated eyes. Respective differences at the fellow eyes were statistically not significant. Two animals developed postoperative complications and were excluded from follow-up.

CONCLUSIONS

Results imply that the implantation of the IPI is feasible in rabbit eyes with significant favorable effects on the IOP, AO and OR.