Intraocular Pressure In Fellow Eye Research Articles

Effect of Selective Laser Trabeculoplasty on the Fellow Eye.

Determine if selective laser trabeculoplasty (SLT) affects the fellow eye's intraocular pressure (IOP). A retrospective review of 76 pairs of eyes from 76 adult glaucoma patients who underwent SLT in one eye with at least 2 months between treatments were evaluated for IOP and medication reduction in the untreated fellow eye. Success was defined as ≥20% IOP reduction or ≥1 medication reduction without any additional IOP lowering procedures or medication. The primary outcome measures were success, IOP, and medication reduction in the untreated fellow eye at 6 months. At 6 months after SLT treatment, 48.7% (38/76) treated eyes and 36.8% (28/76) untreated fellow eyes met success criteria. IOP reduction in the treated eye was 2.6 ± 5.8 (14.1%; p < 0.002) and 0.8 ± 4.3 (5.1%, p = 0.122) in the fellow eye. The fellow eye was significantly more likely to meet success criteria if the treated eye was successful [odds ratio (OR): 6.00, 95% confidence interval (CI) (2.11-17.06), p < 0.002]. After a unilateral treatment with SLT, over one-third of the fellow eyes experienced either ≥20% IOP reduction or medication reduction. Additionally, fellow eyes were six times as likely to meet success criteria if this was observed in the treated eye. These findings may support the proposed biochemical mechanism for the therapeutic action of SLT. The implication for clinicians is that SLT treatment in one eye may allow the fellow eye to benefit and provide a prediction on the fellow eye's response without subjecting both eyes to the rare but present complications of SLT. Hirabayashi M, Mellencamp E, Duong S, et al. Effect of Selective Laser Trabeculoplasty on the Fellow Eye. J Curr Glaucoma Pract 2023;17(4):175-177.

Consensual eye intra-ocular pressure rise following unilateral glaucoma surgery.

Consensual eye intra-ocular pressure (IOP) increase has been reported following ipsilateral glaucoma surgery. The study evaluated the need for increase in anti-glaucoma medications (AGM) ± glaucoma surgery to control the IOP in consensual eye following unilateral glaucoma surgery. Data of 187 consecutive patients who underwent either trabeculectomy or AGV implant were collected. Index (IE) and fellow eye (FE) IOP (baseline, follow-up day 1, week 1, months 1 and 3), acetazolamide and AGM use, FE surgery, glaucoma status, and relevant ophthalmological data were collected. A significant increase from a baseline IOP of 14.4 mmHg was noted at week 1 (15.8 mmHg, p-0.005) and month 1 (15.62 mmHg, p-0.007) in FE (n-187). Among the 61 patients (33%, n-187) who needed additional intervention to reduce FE IOP, 27 (14.4%) underwent FE trabeculectomy. In the IE trabeculectomy group (n-164), significant increase in FE IOP was noted in week 1 (15.87 mmHg, p-0.014) and month 1 (15.61 mmHg, p-0.02), and in the IE AGV group (n-23) at day 1 (15.91 mmHg, p-0.06). Pre-operative acetazolamide resulted in significant increase in FE IOP at week 1 and month 1. Maximum increase in FE IOP of nearly 3.5 mm Hg was noted when IE IOP was persistently <5 mmHg at one month following surgery. Mean FE IOP remained elevated at all visits. An increase in fellow eye IOP needing any additional intervention in a third and surgical intervention in nearly a sixth meant that FE IOP be strictly monitored and addressed following unilateral glaucoma surgery.

Commentary: Consensual ophthalmotonic reaction.

Intraocular pressure (IOP) change in the untreated fellow eye accompanied by a corresponding IOP reduction in the operated eye has been identified as the “consensual ophthalmotonic reaction” (COR), and the terminology was coined by Weekers in 1924.[1] This response was initially observed after contusion, ocular compression, tonography, and cauterization of the sclera.[2] In 1927, Wilmer published the first report on COR after a fistulating surgery in experimental animals.[3] After that, multiple studies have reported the possibility of IOP variation in the fellow eye following unilateral glaucoma surgery, including not only trabeculectomy, but glaucoma drainage device implantations, filtering canaloplasty, and microshunt implantations as well.[4] However, whether there is an IOP increase, decrease, or no change in the fellow eye after glaucoma surgery is still controversial. These contrasting results could be due to differences in the type of glaucoma, preoperative IOP, surgical technique, antimetabolite dosage and duration, time point of observation, and outflow facility of the untreated fellow eye. The postulated mechanisms behind COR include neuronal, hormonal, and cytokine regulation of aqueous flow dynamics.[5] Nevertheless, the exact mechanism is yet to be elucidated. A decrease in IOP in the fellow eye could be associated with improved patient compliance to the antiglaucoma therapy or the effect of systemic absorption of the medications. Also, it could result from a “regression to the mean” effect, as trabeculectomy is often planned when the IOP is high on the variation curve.[6] Regarding COR with topical medications, Newman et al.[7] observed that the IOP reduction in contralateral eyes was found to be associated with timolol only and not prostaglandins or carbonic anhydrase inhibitors. A similar decrease in IOP in the fellow eye has also been reported after laser trabeculoplasty, which might be due to the effects of the systemic release of humoral agents, such as matrix metalloproteinase, and improved medication compliance.[8] An increase in the fellow eye IOP following glaucoma surgery has been observed in the present study. We have also observed an IOP rise in a significant number of patients in the unoperated eye in the early postoperative period after unilateral trabeculectomy, though we do not have published data. Different theories have been postulated that may explain this finding. Weekers[1] explained the possible existence of COR in which activation of the nervous system increased the fellow eye aqueous production. Diestelhorst and Krieglstein[5] also postulated that unilateral filtration surgery triggers a central nervous system-mediated reflective increase in aqueous flow in the unoperated fellow eye to maintain physiological stability. In an animal experiment, a supraoptic controlling pathway has been suggested to lead to an IOP rise in response to water drinking after unilateral optic nerve sections.[9] A few studies described that underperfusion of the trabecular meshwork by aqueous humor in the operated eye and increased extracellular trabecular meshwork material deposition induces a reflex mechanism mediated by specialized cells in the scleral spur that can lead to decreased outflow in the fellow eye.[10] Another hypothesis was an increase in the prostaglandin level in response to the inflammation in the operated eye.[11] Other possible explanations include a postoperative presumed steroid response or withdrawal of antiglaucoma medications.[12] No studies have attributed the increase in IOP in the fellow eye to one factor. In the literature, post-surgical COR is found to occur at an earlier time frame than post-laser COR, which might suggest the role of mechanical triggers rather than chemical triggers in post-surgical COR. The predominance of one mechanism occurring due to a particular intervention may guide the IOP varia tion in the contralateral eye. Further prospective studies and a much more detailed macroscopic overview are needed to delineate the underlying mechanisms and the exact biological role of post-surgical COR. The take-home message is that the fellow eye needs to be carefully monitored after unilateral glaucoma surgery. The fellow eye may be the only eye with vision or the better eye of the two. Also, fellow eyes may be already glaucomatous, that failure to monitor and recognize IOP rise may delay appropriate management leading to glaucoma progression. It is recommended to inform the patient about the possibility of IOP variation in the other eye after glaucoma surgery and the need for multiple visits, especially in the early postoperative period. Another relevant message is that the fellow eyes should not be preferably used as a control in studies assessing the IOP outcomes of a particular treatment or intervention.

Influence of Corneal Visualization Scheimpflug Technology Tonometry on Intraocular Pressure

PurposeTo investigate the effect of Corneal Visualization Scheimpflug Technology tonometry (CST) on intraocular pressure (IOP).DesignCohort study.ParticipantsPatients with and without primary open-angle glaucoma (POAG) were included.MethodsIntraocular pressure was measured using the Icare rebound tonometer (ICRT; Icare Finland Oy) and the biomechanically corrected IOP (bIOP) using the CST. Intraocular pressure was measured at baseline with ICRT, followed by a CST measurement in one eye with the fellow eye acting as a control. Icare measurements were repeated at 10 seconds and 1, 2, 4, 8, 15, 30, and 60 minutes in both eyes. The ratio of test eye IOP to fellow eye IOP was used to control for intrasubject variation.Main Outcome MeasuresIntraocular pressure change following Corneal Visualization Scheimflug Technology tonometry.ResultsForty participants (mean age, 54.09 ± 20.08 years) were included comprising 20 patients with POAG and 20 patients with no ocular abnormalities other than cataract. Mean central corneal thickness was similar in those without POAG (547.4 ± 55.05 μm) and with POAG (520.22 ± 37.59 μm; P = 0.14). No significant change was found in IOP measured with the ICRT in the fellow eye versus the 1-hour period in either the healthy (P = 0.87) or POAG (P = 0.92) group. Significant changes were found in IOP after CST measurement for both healthy (P < 0.01) and glaucomatous (P < 0.01) eyes. After the CST measurement, the IOP reduced continuously from a mean of 13.75 mmHg to 10.84 mmHg at 4 minutes for healthy eyes and from 13.28 mmHg to 11.11 mmHg at 8 minutes for glaucomatous eyes before approaching (83% for healthy eyes and 92% POAG eyes) the pre-CST measurement at 1 hour.ConclusionsCorneal Visualization Scheimpflug Technology tonometry causes a significant reduction in IOP in both glaucomatous and healthy eyes that lasts for at least 1 hour afterward.

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.

Fluctuations of the Intraocular Pressure in One Eye Influence the Intraocular Pressure in the Fellow Eye

ABSTRACTPurpose: To investigate the ophthalmotonic consensual reaction (OCR) in healthy individuals.Methods: This was a cohort study of 59 pairs of eyes of patients who underwent cataract surgery in one eye and had no other ocular pathology than cataract. Main outcome measure was change of intraocular pressure (IOP) in the untreated fellow eye. The IOP was measured 1 hour before, 1 hour after, and 1 day after surgery.Results: One hour after surgery, IOP decreased in 24 (41%) operated eyes (group A). In the corresponding untreated fellow eyes (group Af), the mean IOP (±standard deviation [SD]) did not change (14.1 ± 3.0 mmHg preoperatively to 14.2 ± 3.1 mmHg postoperatively, p = 0.8). Only two operated eyes showed unchanged IOP (group B). In 33 (56%) operated eyes, the IOP increased (group C). In the untreated fellow eyes (group Cf), the mean IOP decreased significantly from 15.1 ± 2.9 to 13.7 ± 2.6 mmHg (p = 0.0012).One day after surgery, the mean IOP of group Af decreased significantly from 14.2 ± 3.1 (postoperative IOP) to 12.7 ± 3.2 mmHg (p = 0.007). In group Cf, the mean IOP revealed no changes from 13.7 ± 2.6 to 13.5 ± 2.4 mmHg (p = 0.69).Conclusions: Our results showed some evidence for the existence of the OCR in healthy individuals. Significant IOP elevation in one eye resulted in IOP reduction in the fellow eye. Interestingly, this phenomenon did not exist vice versa.

Refusal of Trabeculectomy for the Fellow Eye in Collaborative Initial Glaucoma Treatment Study (CIGTS) Participants

To understand the reasons for refusal of fellow eye surgical treatment for glaucoma after first eye trabeculectomy. Post hoc analysis of data collected in a multicenter, randomized clinical trial. Data from participants in the Collaborative Initial Glaucoma Treatment Study (CIGTS) who were randomized to and underwent initial trabeculectomy on their study eye, and whose fellow eye was eligible for surgical treatment, were analyzed. Participant demographic data and characteristics, surgical data from the study eye, and quality-of-life survey results were compared between groups that received or refused trabeculectomy in their fellow eye. The main outcome measure was patient refusal of fellow eye surgery for glaucoma. Of 159 participants who were randomized to and underwent trabeculectomy on their study eye and had a fellow eye that was eligible for surgery, 30 (19%) refused fellow eye surgery. Eligible patients who refused fellow eye trabeculectomy did not differ significantly in visual function or local eye symptoms from those that underwent fellow eye trabeculectomy (all P > .05). In a multivariable analysis of data, increased fellow eye preoperative intraocular pressure (IOP) was associated with decreased odds (OR= 0.89, P= .0188), study eye hypotony at 3months postoperatively was associated with increased odds (OR= 7.24, P= .0125), and argon suture lysis procedure was associated with decreased odds (OR= 0.38, P= .0385) of surgery refusal. Refusal of fellow eye surgery was not uncommonly encountered in the CIGTS. Those who refused fellow eye surgery had lower fellow eye IOP and were more likely to have had hypotony after study eye trabeculectomy.

The Utility of the Monocular Trial: Data from the Ocular Hypertension Treatment Study

To determine whether adjusting the intraocular pressure (IOP) change of the trial eye for the IOP change of the fellow eye (i.e., monocular trial) is a better assessment of medication response than testing each eye independently. Analysis of data from a prospective, randomized, clinical trial. Two hundred six participants with ocular hypertension randomized to the observation group and later started on a topical prostaglandin analog (PGA). Participants were started on a topical PGA in 1 eye and returned in approximately 1 month to determine medication response. The IOP response of the trial eye was determined by the IOP change between baseline and 1 month in the trial eye alone (unadjusted method) and by adjusting for the IOP change in the fellow eye between the same visits (adjusted method). Our "gold standard" for medication response was the IOP change in the trial eye between up to 3 pre- and 3 posttreatment visits on the same medication. Pearson correlation was used to compare the gold standard with the unadjusted and adjusted methods. In addition, symmetry of IOP response between trial and fellow eyes to the same medication was determined by correlating the trial eye IOP change between up to 3 pre- and 3 posttreatment visits to the fellow eye IOP change between the same visits. Correlations of IOP change of the trial eye using the gold standard to the IOP change of the trial eye using the unadjusted and adjusted methods. The correlations of IOP change using the gold standard to the IOP change using the unadjusted and adjusted methods were r = 0.40 and r = 0.41, respectively. The correlation of IOP change of both eyes between the same pre- and posttreatment visits was r = 0.81. The monocular trial (i.e., adjusted method) appears equivalent to testing each eye independently (i.e., unadjusted method); however, neither method is adequate to determine medication response to topical PGAs. Both eyes have a similar IOP response to the same PGA. Further studies to understand IOP fluctuation are necessary to improve current methods of assessing medication response. Proprietary or commercial disclosure may be found after the references.

Concordance of Diurnal Intraocular Pressure between Fellow Eyes in Primary Open-Angle Glaucoma

To study the concordance of diurnal intraocular pressure (IOP) between fellow eyes in primary open-angle glaucoma (POAG). Retrospective chart review. Ninety-three POAG patients. Patients who met the definition of POAG and underwent diurnal curve measurement were included. Subjects were excluded if there was a history of surgery, trauma, ocular vascular disease, incomplete diurnal curve, or asymmetric ocular medication use. Patients on symmetric ocular medication were included and analyzed separately. Goldmann applanation tonometry was performed at 10 am, 1 pm, 4 pm, 7 pm, 10 pm, and 7 am (the next day). The following statistical analyses were performed: (1) average Pearson correlation coefficient (r) from individual correlations of right and left eye IOP over the 6 time points for each subject; (2) linear mixed model analysis for repeated measures, with eye (right and left) and time as the within-subject fixed effects, and (3) absolute difference in change in IOP between fellow eyes over each time interval and probability that the difference was within 2 or 3 mmHg. The concordance of the IOP between fellow eyes as measured by absolute difference in change in IOP between fellow eyes and probability of the difference being within 2 or 3 mmHg. Thirty-seven patients were untreated and 56 were treated on symmetric IOP-lowering medications. The diurnal curves of fellow eyes exhibited parallel profiles according to the linear mixed model. The average difference in the change of IOP between fellow eyes over given time intervals ranged from 1.6 to 2.0 mmHg. The estimated probability that the absolute change in IOP between fellow eyes was within 2 mmHg was 68% to 90%, and within 3 mmHg was 78% to 95% for all time intervals. The diurnal variation of IOP in POAG is largely concordant between fellow eyes. For any given time interval, the fellow eye IOPs may fluctuate asymmetrically a minority of the time. Clinicians who utilize the uniocular trial should be aware of the limit of the IOP concordance.