Intraocular pressure effects of timolol after unilateral instillation

Rapid Retinal Nerve Fiber Layer Thinning in the Unaffected Contralateral Eyes of Patients with Unilateral Normal-Tension Glaucoma: A Retrospective Observational Study

PURPOSE

To observe the rate of progressive retinal nerve fiber layer (RNFL) thinning in the unaffected eyes of patients with unilateral normal-tension glaucoma (NTG), in comparison with that of healthy subjects, and to identify the factors associated with progressive RNFL thinning.

DESIGN

Retrospective, longitudinal, observational study.

PARTICIPANTS

Ninety-five patients with unilateral NTG and 61 healthy controls.

METHODS

This study included unilateral NTG and healthy control subjects who were followed up for longer than 4 years and in whom at least 5 reliable retinal nerve fiber layer thickness (RNFLT) measurements were performed using OCT. Factors associated with the rate of thinning of the unaffected eyes of unilateral patients with NTG were identified using regression analysis.

MAIN OUTCOME MEASURES

The rate of progressive RNFL thinning and the associated factors.

RESULTS

Retinal nerve fiber layer thickness decreased significantly in both the unaffected eyes of unilateral patients with NTG and the healthy eyes (both P < 0.001). The RNFL thinning was significantly faster in the unaffected eyes of unilateral patients with NTG than in the healthy eyes (P < 0.001), specifically in the temporal-inferior (TI) sector (P = 0.003). Factors associated with faster RNFL thinning in the unaffected eyes of unilateral patients with NTG were thicker baseline RNFL of the unaffected eyes (P = 0.002) and a worse visual field (VF) mean deviation (MD) in the NTG eyes (P = 0.040). In the healthy controls, the rate of RNFL thinning in the contralateral eyes was the only factor associated with faster thinning (P = 0.007).

CONCLUSIONS

The unaffected eyes of unilateral patients with NTG showed faster RNFL thinning than healthy control eyes, more obviously in the TI sector, and were likely to progress faster when they had a thicker baseline RNFL, and when the NTG eyes had a worse VF MD. In unilateral patients with NTG, initiation of prophylactic treatment could be considered for the unaffected eyes when they are accompanied by a risk of developing glaucoma.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

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.

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.

Contralateral intraocular pressure lowering effect of prostaglandin analogues

Background:

Though the use of prostaglandin analogues (PGA) for reduction of intraocular pressure (IOP) has shown a marked increase, studies evaluating the contralateral effects of PGA are limited.

Aims:

To evaluate if PGA treatment in one eye has an effect on the IOP of the untreated fellow eye.

Design:

Retrospective study.

Materials and Methods:

Thirty patients of open-angle glaucoma with no previous antiglaucoma treatment underwent 24-hour diurnal IOP phasing. They subsequently were started on a uniocular trial with PGA, and had office diurnal IOP measurements 6 weeks later. Twenty-four hour diurnal consisted of 8 IOP readings over 24 hours and office diurnal consisted of 4 IOP readings between 8 AM and 6 PM at 3 hourly intervals.

Statistical Analysis:

IOPs of the fellow eye during the office diurnal were compared with IOPs at similar time points during the 24-hour diurnal using paired t-tests.

Results:

Mean (± standard deviation) IOP in the treated eye reduced (P < 0.001) from 17.17 ± 3.2 mm Hg at baseline to 13.7 ± 2.4 mm Hg at 6 weeks, while that in the untreated eye reduced from 16.4 ± 3.1 mm Hg to 14.8 ± 2.7 mm Hg (P = 0.01). The decrease in IOP in the untreated fellow eye was statistically significant at 8 AM (2.7 mm Hg, P = 0.003) and 11 AM (2.3 mm Hg, P = 0.01) but not so at 2 PM (1.2 mm Hg, P = 0.10) and 5 PM (0.9 mm Hg, P = 0.19). The amount of IOP reduction in the untreated eye was significantly associated with the magnitude of IOP reduction in the treated eye (β = 0.69, P = 0.008).

Conclusion:

Uniocular PGA treatment tends to reduce the IOP of the untreated fellow eye.

Visual and structural prognosis of the untreated fellow eyes of unilateral normal tension glaucoma patients

PURPOSE

To investigate the visual and structural prognosis of untreated initial non-glaucomatous fellow eyes of unilateral normal tension glaucoma (NTG) patients.

METHODS

In this retrospective observational cohort study, 50 NTG patients with unilateral visual field (VF) loss and no VF defect, retinal nerve fiber layer (RNFL) defect or neuroretinal rim (NRR) notching in the fellow eyes, and those who had initial non-glaucomatous fellow eyes untreated were included. For the fellow eyes, the development of VF defect, RNFL defect, and NRR notching was inspected retrospectively by two observers. Baseline clinical characteristics including initial intraocular pressure (IOP), central corneal thickness, and spherical equivalent (SE) were compared between glaucomatous and fellow eyes.

RESULTS

During the mean follow-up period of 8.77 ± 2.92 years, five patients (10 %) developed RNFL defect and four patients (8 %) developed NRR notching in the fellow eye. Among six patients (12 %) who had developed either RNFL defect or NRR notching, only three patients (6 %) developed VF loss in 1.81, 3.09, and 9.27 years respectively. The initial IOP was significantly higher (p = 0.031), SE was more myopic (p = 0.025), and the occurrence of disc hemorrhage (p = 0.049) was significantly higher in glaucomatous eyes than that in fellow eyes.

CONCLUSIONS

The incidence of glaucoma development in the fellow eye is rather low. Therefore, the initial non-glaucomatous fellow eye of the unilateral NTG patient may be observed without treatment until glaucoma develops.

Safety and efficacy of fluocinolone acetonide intravitreal implant (0.59 mg) in birdshot retinochoroidopathy

PURPOSE

To report the treatment outcomes of the fluocinolone acetonide intravitreal implant (0.59 mg) in patients with birdshot retinochoroidopathy whose disease is refractory or intolerant to conventional immunomodulatory therapy.

METHODS

A retrospective case series involving 11 birdshot retinochoroidopathy patients (11 eyes). Eleven patients (11 eyes) underwent surgery for fluocinolone acetonide implant (0.59 mg). Treatment outcomes of interest were noted at baseline, before fluocinolone acetonide implant, and then at 6 months, 1 year, 2 years, 3 years, and beyond 3 years. Disease activity markers, including signs of ocular inflammation, evidence of retinal vasculitis, Swedish interactive threshold algorithm-short wavelength automated perimetry Humphrey visual field analysis, electroretinographic parameters, and optical coherence tomography were recorded. Data on occurrence of cataract and raised intraocular pressure were collected in all eyes.

RESULTS

Intraocular inflammation was present in 54.5, 9.9, 11.1, and 0% of patients at baseline, 6 months, 1 year, 2 years, 3 years, and beyond 3 years after receiving the implant, respectively. Active vasculitis was noted in 36.3% patients at baseline and 0% at 3 years of follow-up. More than 20% (47.61-67.2%) reduction in central retinal thickness was noted in all patients with cystoid macular edema at 6 months, 1 year, 2 years, and 3 years postimplant. At baseline, 54.5% patients were on immunomodulatory agents. This percentage decreased to 45.45, 44.4, and 14.28% at 1 year, 2 years, and 3 years postimplant, respectively. Adverse events included increased intraocular pressure (54.5%) and cataract formation (100%).

CONCLUSION

The data suggest that fluocinolone acetonide implant (0.59 mg) helps to control inflammation in otherwise treatment-refractory cases of birdshot retinochoroidopathy. It is associated with significant side effects of cataract and ocular hypertension requiring treatment.

Effect of dacryocystorhinostomy on systemic adverse effects of topical timolol maleate

Purpose:

To evaluate whether transformation of the naso-lacrimal passage as happens after dacryocystorhinostomy (DCR) operation has any effect on the systemic adverse effects of topically administered timolol maleate.

Materials and Methods:

Fifty otherwise healthy adult patients without any prior history of cardiac or pulmonary problems scheduled for elective DCR surgery received a drop of timolol maleate 0.5% on the healthy eye. This eye served as a control. Six weeks after successful DCR surgery, the operated eye received the same medication. Parameters compared included intraocular pressure (IOP), pulse rate, blood pressure and forced expiratory volume in the first second (FEV1) findings.

Observations:

Post DCR patients showed an increased incidence of reduced pulse rate and FEV1.

Conclusion:

Timolol maleate ophthalmic preparation should be used with caution in post-DCR patients.

Contralateral effect of topical beta-adrenergic antagonists in initial one-eyed trials in the ocular hypertension treatment study

PURPOSE

To evaluate the magnitude of the contralateral effect of topically administered beta-blockers on intraocular pressure.

METHODS

The Ocular Hypertension Treatment Study enrolled 1,636 subjects. Of these, 817 subjects were randomized to receive topical ocular hypotensive medication and 819 subjects were randomized to close observation (i.e., no topical medication). We compared the intraocular pressure of the contralateral eye of subjects at the baseline visit and after an initial one-eyed therapeutic trial of topical beta-blockers. We examined differences between baseline and follow-up intraocular pressure in untreated eyes of subjects randomized to close observation.

RESULTS

The mean reduction in intraocular pressure in the beta-blocker-treated eyes was -5.9 +/- 3. 4 mm Hg (-22% +/- 12%; Student t test, P <.0001). In the contralateral eyes, mean intraocular pressure reduction was -1.5 +/- 3.0 mm Hg (-5.8% +/- 12%; P <.0001). Of the contralateral eyes, 35% showed a reduction of 3 mm Hg or more, and 10% showed a reduction of 6 mm Hg or more. The contralateral effect of the relatively selective beta-blocker betaxolol did not differ from that of any of the nonselective beta-blockers. Factors associated with the magnitude of the contralateral effect were the degree of intraocular pressure reduction in the treated eye and baseline intraocular pressure of the contralateral eye. In the close observation group, no significant reduction in intraocular pressure was noted between the baseline and follow-up visit.

CONCLUSIONS

The contralateral effect is important in clinical practice and in clinical trials when the hypotensive effect of a topical beta-blocker is evaluated by means of a one-eyed therapeutic trial.

Clinical factors influencing the visual prognosis of the fellow eyes of normal tension glaucoma patients with unilateral field loss

AIM

To investigate the influence of several clinical variables on the development of visual field loss in the "second eye" of patients with normal tension glaucoma (NTG) presenting with unilateral field loss.

METHODS

Patients with NTG and unilateral field loss at presentation were selected from a cohort of 403 consecutive diagnoses of NTG. The state of the visual field "normal" or with a visual field defect was defined using the Advanced Glaucoma Intervention Study (AGIS) template. Where available, optic disc planimetry was carried out on stereo photographs taken at presentation. Measurements of the topography of each of these optic discs were compared with morphometric values from a group of normal subjects, allowing for differences in age and disc size. For each patient the percentage of the relative neuroretinal rim (NRR) area was calculated. The time taken to develop a visual field defect was related to clinical factors including age, sex, peak and mean diurnal intraocular pressure (IOP), refraction, relative NRR area, and the AGIS score of the fellow eye at presentation

RESULTS

54 patients were included in the study. The median (range) follow up time was 49.2 (11.1-116.7) months. 14 (26%) patients developed field loss in the eyes with an initially normal field. The estimate of the median time to field loss onset was 95.1 months. Field damage developed more rapidly in women and in patients with greater AGIS score in the contralateral eye at the beginning of follow up ((adjusted hazard ratio, HR (95% confidence interval, CI) 0.20 (0. 04; 0.93); 1.19 (1.02; 1.41) respectively)). Little evidence of any association was found between time to onset of field loss and each of age, refraction, and peak or mean diurnal IOP. Planimetric disc analysis was carried out in 33 (61%) patients. Of these 10 (30%) developed field loss in the eyes with initial normal field at a median follow up of 95.1 months. After adjustment for sex and AGIS, relative NRR area was found to be significantly related to the time of onset of field damage, the greater the reduction in relative NRR area, the shorter the time to visual field loss (HR 0.93 (0.89; 0. 99)).

CONCLUSIONS

NTG patients with unilateral field loss are at high risk of developing field damage in the eyes with an initially normal visual field. In this study, the visual prognosis of the eye with the normal visual field at presentation was found to be influenced by the extent of the reduction in relative NRR area together with the severity of field damage in the contralateral eye at presentation.

Effects of timolol on visual-field mean retinal sensitivity in normal subjects

This single-blind, randomized study investigated the effects of unilateral instillation of 0.5% maleate timolol twice a day for 7 days on visual-field parameters of both eyes. Twelve normal, young subjects (30.6 +/- 4.2 years) participated in this study. Using program G1 of the Octopus 500 automated perimeter, the visual fields were measured one week and one day before therapy and a third time one week after beginning therapy. The paired T-test was used for statistical analysis, where a P-value < or = 0.05 indicated significance. Whereas nothing statistically significant was found in the treated eyes, the contralateral, untreated eyes showed a statistically significant decrease of mean sensitivity between the first visual fields and the third ones (P < 0.01) This diminution of mean sensitivity in the untreated contralateral eyes may be due to statistically significant lowering of blood pressure (P < 0.01) and slowing of cardiac frequency, which were not compensated by a local decrease of intraocular pressure. If confirmed, these findings could be of clinical importance in the management of glaucoma patients, since some authors have, in some cases, recommended a unilateral therapy.