Visual field survival: the response to timolol therapy in open-angle glaucoma

Influence of Carteolol and Timolol on IOP and Visual Fields in Glaucoma: A Multi-Center, Double-Masked, Prospective Study

The influences of Carteolol and Timolol eye drops on intraocular pressure (IOP) and visual fields were compared in a multi-center, double-masked, prospective study. Two-hundred and forty eyes of 120 patients were initially included in the study, and 142 eyes of 72 patients fulfilled all the criteria for final statistical analysis. Both drugs significantly reduced IOP. The visual fields in both treatment groups did not change during one year of treatment. In both groups some patients improved slightly, and others deteriorated slightly. This indicates that locally applied beta-blockers may efficiently stop further progression of visual field defects in cases with increased IOP and early visual field damage. There was no difference between Carteolol and Timolol in this regard. The side effects were minimal, and there were no differences in their frequency or intensity in the two treatment groups.

Continuous Monitoring of Circadian Variations in Intraocular Pressure by Telemetry System Throughout a 12-Week Treatment with Timolol Maleate in Rabbits

AIM

The aim of this study was to examine the effect of a 12-week treatment with two formulations of timolol maleate on the amplitude of the circadian fluctuation in intraocular pressure (IOP).

METHODS

Conscious Japanese White rabbits housed under a controlled 12-hour light-dark cycle were used. IOP was measured by a telemetry system. Each animal was treated topically for 12 weeks with 0.5% timolol solution (TM) twice-daily, 0.5% timolol gel-forming solution (TM-gel) once-daily, or saline twice-daily, and the circadian variation in IOP was measured every week.

RESULTS

Administration of TM or TM-gel did not change IOP in the light phase, but significantly reduced it in the dark phase in each of the 12 weeks. The IOP reductions at 2 h after administration in the TM and TM-gel groups over the 12 weeks were, respectively, 3.6 +/- 0.3 mmHg and 3.4 +/- 0.2 mmHg versus the Saline group. The amplitudes of the circadian fluctuations in IOP in the TM group in weeks 3, 6, and 12 were 15%, 15%, and 18% smaller than those in the Saline group, while the corresponding values for the TM-gel group were 18%, 16%, and 19%, respectively.

CONCLUSIONS

TM-gel administered once-daily was as effective at lowering IOP as TM administrated twice-daily over the 12-week experimental period. This study reveals that, in rabbits, both formulations of the timolol maleate induced significant IOP reductions in the dark phase and decreased the amplitudes of the circadian fluctuations in IOP for 12 successive weeks.

Sustained perimacular vascular and visual response to topical beta blockers in normal human eyes

PURPOSE

To assess visual and circulatory responses to treatment with topical beta adrenergic antagonists.

DESIGN

Institutional prospective randomized clinical trial in normal adults.

METHODS

Twenty adults (36 (mean) +/- 8 (S.D.) years) underwent repeated baseline perimetry (Humphrey 30-2), contrast sensitivity (Vector Vision), perimacular microcirculatory studies (Oculix blue-field entoptic simulator), intraocular pressure (IOP), heart rate (HR), and blood pressure (BP) testing. Subjects commenced either timolol 0.5% or betaxolol 0.5% twice daily on day 1, were retested on days 3 and 35, discontinued treatment for 21 days, whereupon repeated tests were performed. Treatment responses were compared by paired t-test.

RESULTS

Timolol-treated eyes showed improvement in contrast sensitivity (P=0.03) and pericentral perimetric thresholds (P=0.01), but corresponding increases among betaxolol-treated eyes were significantly higher (P=0.03 and 0.04, respectively, relative to timolol-treated eyes). Leukocyte velocity increased with both drugs, each with post-withdrawal carryover (P< or =0.03). Significant IOP reduction (approximately 2.5 mmHg) occurred in both groups, BP fell 2.8 mmHg among betaxolol-treated subjects (P=0.02), and HR was 2 bpm slower among timolol-treated subjects (P=0.03), but all reverted to baseline values after washout.

CONCLUSIONS

Both treatment groups demonstrated significant changes in visual function and perimacular hemodynamics, sustained after the terminal 3-week washout period.

Inter-observer and intra-observer agreement in the interpretation of visual fields in glaucoma

Visual field changes are one of the main parameters used to monitor progression of glaucoma. This study assesses the degree of intra-observer and inter-observer agreement among nine observers in grading visual fields in glaucoma patients using a visual field system previously described by Jay. The results show a median inter-observer agreement of 61% (median kappa = 0.52) and a median intra-observer agreement of 72% (median kappa = 0.65). This system for grading fields in glaucoma has a high degree of intra-observer agreement, suggesting it is a useful system for longitudinal follow-up of patients by a single observer. The higher degree of disagreement between observers points to the need for careful pretraining of observers in clinical management and research where the results from visual field examinations are to be graded by more than one clinician.

Association of retinal capillary perfusion with visual status during chronic glaucoma therapy

PURPOSE

The purpose of the study is to determine whether retinal microcirculation is associated with the degree of visual function in glaucomatous eyes receiving chronic bilateral medical therapy with topical beta-blockers.

METHODS

A nonrandomized, 3-year prospective clinical study was undertaken on 37 patients with glaucoma and normal visual acuity receiving symmetric topical medication in both eyes. Humphrey 30-2, Henson CFA 2000, and Vistech 3 and 6 cycles/degree contrast sensitivity were obtained bilaterally at multiple visits, along with Oculix 1000 blue-field estimates of perimacular leukocyte velocity. The mean asymmetry of measurements obtained throughout the treatment period for each pair of eyes was determined, and correlations were obtained to assess visual function asymmetry circulatory asymmetry.

RESULTS

Significant associations were observed between blue-field entoptic capillary leukocyte velocity measurements and those for all three visual function testing methods, the eye with the superior vision typically having the higher mean leukocyte velocity (P < 0.001 for both Humphrey mean deviation and Henson perimetry, P < 0.002 for Humphrey corrected pattern standard deviation, and P < 0.02 for contrast sensitivity at both 3 and 6 cycles/degree).

CONCLUSIONS

Central retinal microcirculation is associated with various measures of central and peripheral visual function in glaucomatous eyes receiving beta-adrenergic blocker therapy.

The effect of treatment on the results of high-pass resolution perimetry in glaucoma

In order to find out to which extent high-pass resolution perimetry would detect any changes in patients treated for glaucoma, resolution perimetry results were evaluated from 56 glaucoma patients and 15 untreated ocular hypertensive patients followed for 2 to 3 years. Fifty-nine of the 71 examined patients showed lower resolution thresholds, i.e. increased sensitivity, after 2 years, compared to initial values. The threshold decrease was significantly larger in the treated glaucoma patients (median 1.22 dB) than in the untreated ocular hypertensive patients (0.48 dB). The threshold decrease in the untreated ocular hypertensive group corresponds to the previously described learning effect. In 35 of the 56 treated glaucoma patients the thresholds improved more than 0.84 dB, the upper confidence limit in the untreated group, which may indicate a beneficial effect of antiglaucoma therapy in these patients. The threshold change was unrelated to initial resolution threshold and cannot be explained by a 'sorting' effect. The observations in the current study using resolution perimetry indicate that improved visual function can be demonstrated in many patients treated for early glaucoma, at least during the first 2 years of treatment.

Longterm effect of topical beta-blockers on intraocular pressure and visual field sensitivity in ocular hypertension and chronic open-angle glaucoma

In a prospective, randomized study, nineteen patients with ocular hypertension (n = 14) or chronic open-angle glaucoma (n = 5) were treated with either betaxolol 0.5% or timolol 0.5% in both eyes twice daily. Visual field sensitivity and intraocular pressure were assessed with the Octopus perimeter (program G1) and applanation tonometry, respectively, at 3, 6, 12, 24, 36, and 48 months during treatment. Four of the nineteen patients (two timolol-treated and two betaxolol-treated) were lost to follow-up after the 36-month examination. Whereas both drugs reduced the intraocular pressure, the decrease in the timolol-treated group was statistically more pronounced than in the betaxolol-treated group at month 3, 6, and 48 (p < 0.03). In both treatment groups, the visual field mean sensitivity (MS) index decreased slightly during the first six months of treatment, but remained so only in the timolol-treated group at all subsequent examinations. In the betaxolol-treated group, there was a statistically significant increase in MS at the 12, 24, 36, and 48 month visits (p < 0.01). These findings suggest that factors other than IOP alone may determine visual field outcome.

Longterm visual field follow-up of glaucoma patients treated with beta-blockers

In a prospective, randomized, double-masked study, 44 patients with primary open-angle glaucoma were treated either with 0.5% betaxolol or 0.5% timolol in both eyes twice daily. Twenty-nine patients could be followed up for 48 months. Seventeen of these patients were treated with betaxolol and 12 with timolol. Each examination included visual field measurements with an Octopus automated perimeter 201 (Program G1), intraocular pressure measurement, funduscopy, as well as pulse and arterial blood pressure measurements. Both drugs lowered in the intraocular pressure. This reduction was slightly but not statistically significantly higher in the timolol-treated group. However, the visual fields improved more in the betaxolol group. Patients treated with betaxolol had significantly smaller averaged mean defects (p < 0.05) and higher averaged mean sensitivities (p < 0.05, Wilcoxon rank score text) than did timolol-treated patients at months 3, 6, 12, and 18. Thereafter, the difference between the two groups was not statistically significant in this relatively small sample size. For betaxolol patients the cumulative area-under-the-curve analysis for the worse eye yielded significantly larger mean sensitivities beyond month 12 (exception: month 30; p < 0.05) and significantly smaller mean defects beyond month 6 (p < 0.05).

Effect of timolol versus pilocarpine on visual field progression in patients with primary open-angle glaucoma

BACKGROUND

Relatively few studies have been conducted linking decreasing intraocular pressure (IOP) to preservation of visual field. This investigation was conducted to determine if this link could be made and to compare the long-term effect of two ocular hypotensive agents on preservation of visual field.

METHODS

In an observer-masked study, 189 patients with primary open-angle glaucoma received either timolol or pilocarpine by random allocation. The dose of antiglaucoma agent was increased from 0.25% to 0.5% twice daily for timolol or from 2% to 4% four times daily for pilocarpine if the initial IOP response was inadequate. After an on-treatment baseline, visual fields were followed every 4 months for 2 years using the Octopus program 32.

RESULTS

Compared with timolol, significantly more patients receiving pilocarpine discontinued use because of inadequate IOP control (P < or = 0.01). By comparing the mean visual field scores, it can be seen that the pilocarpine group had a significantly worse score at all timepoints from month 4 to month 24. The pilocarpine group also had a greater mean number of test loci with decreased sensitivity of 5 or more decibels (dB) at all timepoints. The mean within-patient regression slope for timolol was 0.01 dB/month and for pilocarpine was -0.06 dB/month (P < 0.01). The study has shown that over a 2-year period, patients treated with pilocarpine 2% or 4% four times daily experienced a significantly greater visual field deterioration than that seen in patients receiving either 0.25% or 0.5% timolol twice daily.

CONCLUSION

Although these data do not support a link between lowering of IOP and visual field preservation, treatment with timolol was associated with significantly less visual field loss than treatment with pilocarpine.

Influence of betaxolol and timolol on the visual fields of patients with glaucoma

In a double-masked study, 40 patients with primary open-angle glaucoma were randomly assigned to treatment with betaxolol 0.5% or timolol 0.5% in both eyes twice daily. Visual fields and intraocular pressures were studied. Perimetry was performed with the Octopus G1 program two weeks after a washout period and three, six, 12, and 18 months after initiation of treatment. Both drugs reduced intraocular pressure. The reduction in intraocular pressure in the timolol-treated group was more pronounced than that in the betaxolol-treated group; the difference, however, was not statistically significant. In both treatment groups, the visual fields tended to improve during the first six months of treatment and remained stable or tended to deteriorate thereafter. The treatment effect on the visual field was better in the betaxolol-treated group than it was in the timolol-treated group (P = .041).

Association between intraocular pressure and loss of visual field in chronic simple glaucoma

This paper reports the analyses on data from 747 patients with chronic simple glaucoma (CSG) recorded in the King's College Hospital glaucoma data base between January 1970 and February 1985, having a mean follow-up time of 5.1 years (mode 8 years) with the object of determining the relationship of intraocular pressure (IOP) and visual field loss in CSG. A highly significant negative relationship was found between the presenting visual field coefficient (FC) and the untreated IOP (r = -0.26, p = 0.0001) - that is, the higher the IOP on detection, the worse is the visual field. A weak negative correlation was present between the change of FC per year and the treated IOP (r = -0.06), p = less than 0.05). At treated IOPs less than or equal to 18 mmHg visual field loss averaged 0.6 unit per year and for IOPs greater than 18 mmHg the average loss was 1.2 units per year. The data confirm both the importance of a raised IOP in the causation of chronic glaucomatous visual field loss and the importance of reducing the IOP in patients with chronic simple glaucoma.

A long-term clinical trial of timolol therapy versus no treatment in the management of glaucoma suspects

One hundred seven patients with intraocular pressures (IOPs) between 22 and 28 mmHg with normal visual fields on Goldmann perimetry and without evidence of optic nerve damage were randomly assigned to either a timolol treatment (TT) or a no treatment (NT) arm in a prospective clinical trial. The patients were followed for an average of 56 and 51 months, respectively. Criteria for failure were a confirmed IOP of greater than 32 mmHg, stereophotographically documented optic nerve progression, or development of glaucomatous visual field loss by Goldmann or Octopus perimetry. Nine patients failed in the TT group and 17 in the NT group (P = 0.07). Of the nine TT group failures, six had discontinued timolol before failure (4 for greater than 6 months). In a Cox proportional hazards analysis controlling for confounding variables, timolol was found to be significantly protective with an adjusted risk ratio of 0.38 (95% confidence interval = 0.16-0.89, P = 0.03). When only field and disc failure criteria were considered, timolol treatment was found to be significantly protective in an analysis considering patients who stopped timolol as being lost to follow-up (P = 0.05). A higher tonographic facility of outflow was protective in all analyses. A trend toward a substantial loss of effectiveness of timolol on IOP was not observed. Seasonal fluctuations in IOP were observed (P = 0.0007), with higher IOP occurring in the winter. The results demonstrate a favorable influence of timolol therapy on the clinical course of patients with mildly elevated IOP.(ABSTRACT TRUNCATED AT 250 WORDS)

The visual field in chronic simple glaucoma and ocular hypertension; its character, progress, relationship to the level of intraocular pressure and response to treatment

Nine hundred and twenty-nine patients with chronic simple glaucoma or ocular hypertension were followed for one to thirteen years using the King's College Hospital glaucoma data base. The 30 degree visual field was divided into twelve clinical zones. The field sensitivity and its change as measured by the mean differential threshold both in these zones and overall was followed to determine the pattern and progress of field loss in eyes diagnosed initially as chronic simple glaucoma or ocular hypertension. The findings were related to other similar analyses in which the mean differential threshold in chronic glaucoma was found to correlate significantly with the initial intraocular pressure and its progress with the mean follow-up intraocular pressure under treatment. Inferences were drawn regarding the nature of chronic simple glaucoma and ocular hypertension and their management.

Referral patterns to an ophthalmic outpatient clinic by general practitioners and ophthalmic opticians and the role of these professionals in screening for ocular disease

Case notes of 1113 consecutive new patients referred to a consultant ophthalmologist at a district general hospital were reviewed to determine the source and efficacy of referrals and the current screening practices of general practitioners and ophthalmic opticians. General practitioners initiated referral in 546 cases (49%) and ophthalmic opticians referral in 439 (39%). Visual loss or visual disturbance was the most important single reason for referral (345 cases; 31%), followed by suspected glaucoma (145 cases; 13%), abnormalities of binocular vision (140; 12.5%), disorders of eyelids or ocular adnexa (127; 11%), and red eye (86; 8%). General practitioners referred many more patients with disorders of the eyelids and adnexa and ophthalmic opticians many more patients with suspected glaucoma. Ophthalmic opticians were far more likely than general practitioners to refer patients with suspected glaucoma correctly. A total of 180 patients (16%) were referred from ocular screening, in 149 cases by ophthalmic opticians and in 10 by general practitioners. Seventy patients had glaucoma or incomplete features of glaucoma, all of them referred by ophthalmic opticians. Of eight diabetic patients referred by ophthalmic opticians, three had asymptomatic disease and in two diabetes was diagnosed as a result of ocular screening. No patient was referred for asymptomatic diabetic retinopathy from screening by general practitioners. Ophthalmic opticians were more likely than general practitioners to diagnose retinopathy requiring photocoagulation. Use of a community based service to screen for glaucoma could save unnecessary consultant outpatient appointments. A similar service could facilitate detection of diabetic retinopathy at a stage when treatment is most effective.

A comparative evaluation of timolol maleate and pilocarpine in the treatment of chronic open angle glaucoma

Ninety-two eyes with newly-diagnosed chronic open angle glaucoma (COAG) were treated in a randomised prospective trial with either timolol or pilocarpine. Their visual field survival was monitored on a 3-monthly basis over 2 years using both Goldmann and Friedmann perimetry. Concomitant tonometric data was derived by applanation. Fields were assessed and quantified using algorithms designed to give the greatest sensitivity for glaucomatous field loss. Microcomputer programmes specifically designed for this purpose were used in the data collection and subsequent analysis.

Automated differential threshold perimetry for detecting glaucomatous visual field loss

Because early glaucomatous visual field defects occur asymmetrically across the horizontal meridian, we analyzed data from automated perimetry by comparing sums of threshold values of corresponding groups of points in the superior and inferior hemispheres of the central 30 degrees tested by the Humphrey Field Analyzer. We developed patterns and criteria from 25 early glaucomatous and 36 normal control eyes to achieve optimal balance between sensitivity (96%) and specificity (86%). Application of these criteria to an independent group of 27 glaucomatous and 105 control eyes yielded a sensitivity of 88.9% and specificity of 85.7%. Minor modification of the criteria improved sensitivity and specificity to more than 90% for both patients and controls.

Informational content of visual field location in glaucoma

Information Theory has been applied to produce estimates of how valuable each stimulus location on the Friedmann Visual Field Analyser mk. II is in detecting early glaucomatous visual field defects. The results indicate that stimuli in the superior arcuate region of the visual field and in the inferior nasal quadrant give the maximum amount of information. Stimuli in the extreme superior field (beyond 20 degrees), the inferior temporal quadrant and around the physiological blind spot give the least amount of information. It is suggested that these results can be used to develop computerised techniques for the analysis of visual field data.