Central corneal thickness in the Ocular Hypertension Treatment Study (OHTS)

OBJECTIVE

Central corneal thickness influences intraocular pressure (IOP) measurement. We examined the central corneal thickness of subjects in the Ocular Hypertension Treatment Study (OHTS) and determined if central corneal thickness is related to race.

DESIGN

Cross-sectional study.

PARTICIPANTS

One thousand three hundred one OHTS subjects with central corneal thickness measurements.

INTERVENTION

Central corneal thickness was determined with ultrasonic pachymeters of the same make and model at all clinical sites of the OHTS.

MAIN OUTCOME MEASURES

Correlation of mean central corneal thickness with race, baseline IOP, refraction, age, gender, systemic hypertension, and diabetes.

RESULTS

Mean central corneal thickness was 573.0 +/- 39.0 microm. Twenty-four percent of the OHTS subjects had central corneal thickness > 600 microm. Mean central corneal thickness for African American subjects (555.7 +/- 40.0 microm; n = 318) was 23 microm thinner than for white subjects (579.0 +/- 37.0 microm; P < 0.0001). Other factors associated with greater mean central corneal thickness were younger age, female gender, and diabetes.

CONCLUSIONS

OHTS subjects have thicker corneas than the general population. African American subjects have thinner corneas than white subjects in the study. The effect of central corneal thickness may influence the accuracy of applanation tonometry in the diagnosis, screening, and management of patients with glaucoma and ocular hypertension.

Clinical factors associated with progression of glaucomatous optic disc damage in treated patients

BACKGROUND

Reducing intraocular pressure (IOP) in glaucomatous eyes does not always prevent disease progression.

OBJECTIVE

To determine the clinical factors associated with progressive optic disc damage in glaucomatous eyes receiving treatment to reduce IOP.

METHODS

Baseline and follow-up optic disc photographs as well as demographic and clinical data were retrospectively studied in 186 eyes of 93 patients with primary open-angle glaucoma, and in 138 eyes of 69 patients with normal-pressure glaucoma. The patients with primary open-angle glaucoma were included in the study only if their treated IOPs during a follow-up period of 5 years were less than 21 mm Hg. The patients with normal-pressure glaucoma were included only if their IOPs were reduced by at least 20% during the follow-up period. The association of progressive optic disc damage with patient- and eye-specific characteristics was examined using multivariate analysis.

RESULTS

During the 5-year study period, 141 (43.5%) of the 324 eyes exhibited progressive optic disc damage defined by at least a 5% decrease in the neural rim area-to-disc area ratio. Using multivariate analysis, the following were found to be strongly associated with progressive neural rim damage: a baseline smaller neural rim area-disc area ratio (P<.001); a baseline larger zone beta area-disc area ratio (P =.04); a baseline larger parapapillary atrophy length-disc circumference ratio (P =.05); a diagnosis of normal-pressure glaucoma (P =.01); and combined medical and surgical treatment prior to the study period (P =.01).

CONCLUSIONS

Clinical factors other than IOP may be important indicators of subsequent progression of glaucomatous optic disc damage. Our findings suggest that eyes with advanced glaucomatous optic disc damage and normal-pressure glaucoma are more likely to progress despite receiving treatment to reduce IOP.

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.

Confirmation of visual field abnormalities in the Ocular Hypertension Treatment Study. Ocular Hypertension Treatment Study Group

OBJECTIVE

To determine the frequency with which visual field abnormalities observed on follow-up visual fields for patients in the Ocular Hypertension Treatment Study were confirmed on retest.

METHODS

Between April 1, 1994, and March 1, 1999, 21,603 visual fields were obtained from 1637 patients in the Ocular Hypertension Treatment Study. When follow-up visual fields are outside the normal limits on the Glaucoma Hemifield Test, the Corrected Pattern Standard Deviation (P<.05), or both, subsequent follow-up visual fields are monitored to confirm the abnormality. Abnormalities are confirmed if they are again abnormal on the Glaucoma Hemifield Test, the Corrected Pattern Standard Deviation, or both; if the defect is not artifactual; and if the same index and location are involved. Reliability criteria used by the study consisted of a limit of 33% for false positives, false negatives, and fixation losses.

RESULTS

Of the 21,603 regular follow-up visual fields, 1006 were follow-up retests performed because of an abnormality (n = 748) or unreliability (n = 258). We found that 703 (94%) of the 748 visual fields were abnormal and reliable, and 45 (6%) were abnormal and unreliable. On retesting, abnormalities were not confirmed for 604 (85.9%) of the 703 originally abnormal and reliable visual fields.

CONCLUSIONS

Most visual field abnormalities in patients in the Ocular Hypertension Treatment Study were not verified on retest. Confirmation of visual field abnormalities is essential for distinguishing reproducible visual field loss from long-term variability. Arch Ophthalmol. 2000;118:1187-1194

Concordance of parapapillary chorioretinal atrophy in ocular hypertension with visual field defects that accompany glaucoma development

OBJECTIVE

To determine whether the extent and location of progressive parapapillary chorioretinal atrophy noted in some patients with ocular hypertension are correlated with the extent and location of visual field defects that occur with progression to glaucoma.

STUDY DESIGN

Retrospective cohort study.

PARTICIPANTS

Thirty patients with ocular hypertension who had progressive changes of parapapillary atrophy develop before clinically detectable optic disc or visual field damage.

MAIN OUTCOME MEASURES

Assessment of changes in the parapapillary atrophy and visual field parameters.

METHODS

Baseline and follow-up optic disc photographs and visual field test results were retrospectively analyzed. The relationship between the extent of parapapillary atrophy observed during the ocular hypertension period and initial visual field abnormalities detected after glaucoma development, as well as their spatial relationship, was statistically analyzed.

RESULTS

The extent of progressive changes of the parapapillary atrophy detected during the ocular hypertension period was correlated with the extent of changes in the visual field parameters, including corrected pattern standard deviation and mean deviation measured after glaucoma development (Mantel-Haenszel chi-square test, P = 0.026, P = 0.037, respectively). In addition, the visual field abnormalities occurred in the corresponding quadrants of the progressive parapapillary atrophy. Analysis of the spatial relationship revealed that the location of progressive changes of the parapapillary atrophy was concordant with the location of visual field abnormalities in 78% of the quadrants (94 of 120 quadrants) (chi-square test, P = 0.001).

CONCLUSIONS

The extent and location of visual field abnormalities that develop in ocular hypertensive eyes with progression to glaucoma exhibit a concordance with the extent and location of progressive parapapillary atrophy noted in the ocular hypertension period. This suggests the importance of detailed examination of the parapapillary area in ocular hypertensive eyes.

The Ocular Hypertension Treatment Study: design and baseline description of the participants

BACKGROUND

The Ocular Hypertension Treatment Study (OHTS) seeks to evaluate the safety and efficacy of topical ocular hypotensive medication in preventing or delaying the onset of visual field loss and/or optic nerve damage in subjects with ocular hypertension at moderate risk for developing primary open angle glaucoma.

OBJECTIVE

To describe the study protocol, the questions to be answered, and the baseline characteristics of the subjects.

DESIGN

Multicenter randomized clinical trial with 2 groups: topical ocular hypotensive medication and close observation.

SETTING

Subjects were enrolled and evaluated at 22 participating clinical centers. Visual fields and stereoscopic optic disc photographs were read in masked fashion.

METHODS

We determined eligibility from a comprehensive eye examination, medical and ocular history, visual field testing, and stereoscopic optic disc photography.

RESULTS

We describe the baseline characteristics of 1637 subjects randomized between February 28, 1994, and October 31, 1996. The mean age was 55 years; 56.9% of the subjects were women; and 25% were African American. The baseline intraocular pressure was 24.9 +/- 2.7 mm Hg (mean +/- SD). Systemic diseases and conditions reported by subjects included previous use of medication for ocular hypertension, 37%; systemic hypertension, 38%; cardiovascular disease, 6%; diabetes mellitus, 12%; and family history of glaucoma, 44%. The mean horizontal cup-disc ratio by contour estimated from stereophotography was 0.36 +/- 0.18. Qualifying Humphrey 30-2 visual fields had to be normal and reliable for entry into the study. Health-related quality of life (36-item short form health survey) scores in the OHTS sample were better than the age- and sex-matched population norms. African American subjects had larger baseline cup-disc ratios and higher reported rates of elevated blood pressure and diabetes than the rest of the subjects.

CONCLUSIONS

The intraocular pressure among enrolled subjects was sufficiently high to provide an adequate test of the potential benefit of ocular hypotensive medication in preventing or delaying glaucomatous damage. The large number of African American subjects enrolled should provide a good estimate of the African American response to topical medication.

Late removal of releasable sutures after trabeculectomy or combined trabeculectomy with cataract extraction supplemented with antifibrotics

PURPOSE

Releasable scleral flap sutures have been effectively used in trabeculectomy. The suggested time for suture removal is within the first two postoperative weeks. The authors wished to determine whether the use of intraoperative antifibrotics alters the time of suture removal and the results of surgery.

METHODS

The charts of 324 patients (388 eyes) undergoing trabeculectomy and 141 patients (174 eyes) undergoing combined trabeculectomy with cataract extraction with a minimum follow-up of 12 months were retrospectively reviewed. All eyes received intraoperative antifibrotics; mitomycin C in 534 eyes and 5-fluorouracil in 29 eyes. Two releasable scleral flap sutures were used in all of the eyes.

RESULTS

The removal time of at least one of the two releasable sutures was later than 21 days postoperatively in 89 eyes of 83 patients with trabeculectomy (22.9%) and in 58 eyes of 55 patients with combined surgery (33.3%). The suture removal was deferred in 39 eyes because of an early complication such as hypotony (intraocular pressure (IOP) < or = 5 mm Hg), bleb leak, or shallow or flat anterior chamber. There was no complication in the other 108 eyes, but suture removal was delayed until the IOP was more than 10 mm Hg. Immediate IOP reduction was (mean +/- standard deviation) 6.3 +/- 2.8 mm Hg when suture removal was performed beyond 3 weeks. There was a decreased response as the postoperative time until suture removal increases (r = -0.57). No serious complication associated with late suture removal was noted during the follow-up period (mean +/- standard deviation, 19.8 +/- 10.1 months).

CONCLUSION

Intraoperative pharmacologic modulation of wound healing in trabeculectomy and combined trabeculectomy with cataract extraction extends the period that releasable suture removal is clinically effective. However the response decreases with a longer interval to releasable suture removal.

Parapapillary chorioretinal atrophy in patients with ocular hypertension. II. An evaluation of progressive changes

OBJECTIVE

To determine whether parapapillary chorioretinal atrophy in patients with ocular hypertension remained stationary or progressed along with glaucomatous optic nerve damage.

METHODS

The morphometric parameters and progression of parapapillary atrophy were retrospectively investigated, using serial photographs, in 350 eyes of 175 patients with ocular hypertension. The association of parapapillary atrophy progression with subsequent glaucomatous conversion and with other baseline patient- and eye-specific characteristics was analyzed.

RESULTS

Progression in the area and extension of parapapillary atrophy before noticeable optic disc or visual field changes was observed in 48 (49.0%) of 98 eyes that converted to glaucoma, while parapapillary atrophy progression was noted in 25 (9.9%) of 252 ocular hypertensive eyes that did not develop glaucomatous damage (P<.001). The predictive sensitivity and specificity of this observation were 49% and 90%, respectively. In a logistic multiple regression model, the progression of parapapillary atrophy was associated with a family history of glaucoma (odds ratio, 2.7) and the initial size of zone beta (odds ratio, 1.64, for an increase of 0.10 of the zone beta area-disc area ratio).

CONCLUSION

The progression of parapapillary chorioretinal atrophy may be an early glaucomatous finding in some patients with ocular hypertension.

Parapapillary chorioretinal atrophy in patients with ocular hypertension. I. An evaluation as a predictive factor for the development of glaucomatous damage

OBJECTIVE

To determine whether parapapillary chorioretinal atrophy is a risk factor for the development of glaucomatous optic disc or visual field damage.

METHODS

The initial morphometric parameters of the optic disc and parapapillary atrophy were retrospectively investigated in 350 eyes of 175 patients with ocular hypertension. The prognostic value of parapapillary atrophy at the baseline examination and its relationship with known risk factors for the development of glaucomatous damage were analyzed by multivariate analysis.

RESULTS

Visual field loss, optic disc damage, or both were detected in 98 eyes of 53 patients during the follow-up period of at least 10 years. By univariate analysis, the presence of parapapillary atrophy, as well as higher parapapillary atrophy area-disc area, zone beta area-disc area, and parapapillary atrophy length-disc circumference ratios, at the baseline examination was associated with the conversion to glaucoma. In addition, higher intraocular pressure, larger vertical cup-disc ratio, and smaller neural rim area-disc area ratio at the baseline examination were associated with subsequent glaucomatous optic nerve damage. In a multivariate regression model adjusted for other factors, intraocular pressure (relative risk, 1.19), neural rim area-disc area ratio (relative risk, 0.72), and zone beta area-disc area ratio (relative risk, 1.32) were found to be associated with the development of optic disc damage, visual field damage, or both.

CONCLUSION

The presence and the size of parapapillary atrophy are related to the development of subsequent optic disc or visual field damage in patients with ocular hypertension.

Comparative results of combined procedures for glaucoma and cataract: II. Limbus-based versus fornix-based conjunctival flaps

BACKGROUND AND OBJECTIVE

One of the variables to be considered in a combined procedure for glaucoma and cataract is the type of conjunctival flap to be used. The objective of this study was to compare the effects of limbus-based and fornix-based conjunctival flaps on postoperative long-term intraocular pressure (IOP) control and visual acuity after combined trabeculectomy with phacoemulsification.

PATIENTS AND METHODS

The authors retrospectively reviewed the charts of 189 patients (215 eyes) who underwent combined trabeculectomy with phacoemulsification, posterior chamber intraocular lens (IOL) implantation, and intraoperative mitomycin-C administration and who had a minimum follow-up of 12 months. The results of the limbus-based (151 eyes) versus fornix-based (64 eyes) conjunctival incisions used in these combined procedures were compared.

RESULTS

In the limbus-based conjunctival flap group, 146 eyes (97%) achieved an IOP of less than 20 mm Hg, with or without medication; 62 eyes (97%) of the fornix-based conjunctival flap group (P > .05) achieved this result. A visual acuity of 20/40 or better was noted in 106 eyes (70%) in the limbus-based conjunctival flap group and in 45 eyes (70%) in the fornix-based conjunctival flap group (P > .05) at the last examination. Early wound leakage was observed more frequently in the fornix-based conjunctival flap group (8% vs 1%) (P = .014); however, it was not a serious clinical problem, as only 1 eye required surgical repair. Posterior capsular opacification was found more often in the limbus-based conjunctival flap group (25% vs 14%) (P = .072) and required more frequent laser capsulotomy (22% vs 9%) (P = 0.03).

CONCLUSION

Limbus-based and fornix-based conjunctival flaps appear to be comparable with respect to postoperative IOP control and visual acuity after a combined trabeculectomy with phacoemulsification and posterior chamber IOL implantation in cases supplemented by intraoperative mitomycin-C.

Comparative results of combined procedures for glaucoma and cataract: I. Extracapsular cataract extraction versus phacoemulsification and foldable versus rigid intraocular lenses

BACKGROUND AND OBJECTIVES

The refinements of small-incision cataract surgery by phacoemulsification with foldable intraocular lens (IOL) implantation have recently permitted new options for combined trabeculectomy with cataract extraction. The objectives of this study were to compare the long-term intraocular pressure (IOP) control and visual outcome between trabeculectomies combined with extracapsular cataract extraction (ECCE) versus those with phacoemulsification, and to analyze these same factors for foldable versus rigid IOLs.

PATIENTS AND METHODS

The authors retrospectively reviewed the charts of 311 patients (397 eyes) who underwent combined trabeculectomy with cataract extraction and posterior chamber IOL implantation. In all of the surgeries, releasable scleral flap sutures were used. The mean follow-up was 22.9 +/- 15.1 months, with a minimum follow-up of 12 months.

RESULTS

Trabeculectomy combined with phacoemulsification had a lower postoperative complication rate and was more effective than trabeculectomy combined with ECCE in reducing IOP to less than 20 mm Hg with or without medication (95% vs 82%) and in improving vision to levels of 20/40 or better (71% vs 52%) (P < .001). Regarding IOLs, foldable silicone lenses were found to be an effective alternative to polymethylmethacrylate lenses in combined surgeries in terms of a controlled IOP of less than 20 mm Hg (97% vs 97%) and visual recovery to 20/40 or better (78% vs 63%).

CONCLUSION

The combination of trabeculectomy with releasable scleral flap sutures and small incision cataract surgery with foldable IOL implantation has improved postoperative IOP control and visual rehabilitation.

Primary valve malfunction of the Krupin eye valve with disk

PURPOSE

To examine the management and possible causes of primary valve malfunction of the Krupin eye valve with disk.

METHODS

The authors reviewed the results of 113 patients undergoing implantation of the Krupin eye valve with disk and identified eight patients with primary valve malfunction requiring surgical revision.

RESULTS

Valve revision involved manipulation (n = 1 case), explantation of the malfunctioning valve and implantation of a new valve (n = 2), and amputation of the valve (n = 5). Six of eight patients had final intraocular pressures of < 21 mmHg on one or no medications at a mean interval of 15.9 months (range 5-36) after surgical revision. Transient postoperative hypotony was noted in three patients and chronic hypotony with loss of light perception in one patient. One explanted valve was examined and found to have partially fused leaflets.

CONCLUSIONS

Surgical revision in cases of primary valve malfunction of the Krupin eye valve with disk may be accomplished relatively safely with an acceptable level of postoperative complications. The etiology of primary valve malfunction may be related to the sterilization process and prolonged storage before implantation.

Plasma and aqueous humor endothelin levels in primary open-angle glaucoma

PURPOSE

Endothelins (ET) have some effects on the regulation of aqueous humor dynamics. To investigate their possible role in glaucoma, we measured plasma and aqueous humor ET levels in patients with and without primary open-angle glaucoma.

METHODS

Plasma and aqueous humor samples were obtained from 31 patients with primary open-angle glaucoma and 24 patients without glaucoma. Measurements were made by radioimmunoassay (RIA) for ETs with the following cross-reactivities: ET-1, ET-2, and big ET-1, 100%; and ET-3, 70%.

RESULTS

The ages (mean +/- SD) of the patients with primary open-angle glaucoma (72.3 +/- 10 years) and normal subjects (72.8 +/- 8 years) were similar (p = 0.92). There was no significant difference between plasma ET levels of the two groups (p = 0.07). However, aqueous humor ET levels (mean +/- SD) were higher in the primary open-angle glaucoma group (44.26 +/- 2.6 pg ml-1) than in normal subjects (42.17 +/- 1.6 pg ml-1) (p = 0.001). The ratios of corresponding aqueous humor to plasma levels of ETs were approximately 10% higher in the primary open-angle glaucoma group (3.76) than in normal subjects (3.41) (p = 0.0002).

CONCLUSIONS

The small increase in aqueous humor endothelin levels in patients with primary open-angle glaucoma versus controls of similar age may be relevant to the understanding of the various roles of ETs in aqueous humor dynamics in these patients.

Comparative optic disc analysis in normal pressure glaucoma, primary open-angle glaucoma, and ocular hypertension

PURPOSE

The authors wished to determine whether characteristics of optic disc and parapapillary atrophy differ between eyes with ocular hypertension, primary open-angle glaucoma (POAG) and those with normal-pressure glaucoma, including a subset of patients with normal-pressure glaucoma with evidence of serum abnormalities of humoral autoimmunity.

METHODS

Three hundred ninety-two eyes of 196 patients with ocular hypertension, 394 eyes of 197 patients with POAG, and 135 eyes of 68 patients with normal-pressure glaucoma were analyzed. Nerve fiber layer hemorrhage in the optic disc region, retinal arteriolar narrowing, and morphometric parameters of optic disc and parapapillary atrophy were investigated in these groups. Parapapillary atrophy was differentiated in two different zones (alpha and beta).

RESULTS

Nerve fiber layer hemorrhage and arteriolar narrowing were found more frequently in patients with normal-pressure glaucoma than in patients with POAG (P = 0.014, P = 0.004) and ocular hypertension (P < 0.0001, P < 0.0001). Zone beta was detected more often in patients with normal-pressure glaucoma than in those with ocular hypertension (P < 0.001) and POAG (P = 0.013). Although patients with normal-pressure glaucoma had more advanced neural rim loss and larger parapapillary atrophy, there were similar correlations between neural rim area and the area and extension of parapapillary atrophy in patients with normal-pressure glaucoma and POAG. Parapapillary atrophy parameters also were similar in different stages of neural rim damage in patients with normal-pressure glaucoma and POAG (P > 0.05). Optic disc characteristics were not different (P > 0.05) between the subgroups of patients with normal-pressure glaucoma.

CONCLUSION

The authors' findings support the idea that besides the enlargement of the area and extension of parapapillary atrophy that accompanies neural damage in glaucoma, the severity of the parapapillary atrophy also increases as assessed by the increase in zone beta in more damaged eyes. Furthermore, the final clinical appearance of optic nerve damage is similar among patients with POAG, normal-pressure glaucoma, and the subgroups of normal-pressure glaucoma, regardless of their possibly different mechanisms of neuropathy.

Trabeculectomy with releasable sutures

OBJECTIVE

To determine whether the use of releasable scleral-flap sutures affects the success rate and the incidence of complications following trabeculectomy.

DESIGN

A retrospective chart review of a consecutive series of trabeculectomies.

SETTING

A university-based referral practice.

PATIENTS

Two hundred fifty-eight consecutive patients (274 eyes) undergoing trabeculectomy because of uncontrolled glaucoma.

INTERVENTION

During the first year, 124 patients (128 eyes) underwent trabeculectomies with permanent scleral-flap sutures. During the second year, 134 patients (146 eyes) underwent trabeculectomies with releasable scleral-flap sutures.

MAIN OUTCOME MEASURES

Incidence of flat and shallow anterior chamber, incidence of operations to drain choroidal detachment and to re-form anterior chamber, and long-term control of intraocular pressure.

RESULTS

In the group with permanent sutures, 42 eyes (32.8%) had clinically detectable shallowing of the anterior chamber in the early postoperative period. In contrast, a shallow anterior chamber was noted in 21 eyes (14.4%) in the group with releasable sutures (P = .0003). Flat anterior chamber, defined as iridocorneal apposition to the pupil margin, occurred in 11 eyes with permanent sutures (8.6%) but in only two eyes (1.4%) with releasable sutures (P = .0078). Surgical intervention to drain suprachoroidal fluid and re-form the anterior chamber was required in eight eyes with permanent sutures (6.2%) but in only one eye with releasable sutures (0.7%) (P = .014). At 1-year follow-up, the two groups were similar in terms of intraocular pressure and the need for ocular hypotensive medications.

CONCLUSIONS

Releasable scleral-flap sutures reduce the incidence of shallow and flat anterior chamber after trabeculectomy without compromising long-term control of intraocular pressure.

Follow-up of angle-closure glaucoma suspects

One hundred twenty-nine patients thought to be at risk for developing angle-closure glaucoma underwent a baseline examination, which included gonioscopy, refraction, anterior chamber pachymetry, ultrasound biometry, and an angle-closure provocative test. Patients were then followed up with no treatment. Mean follow-up was 2.7 years with a range up to six years. Twenty-five patients developed angle closure in at least one eye during the follow-up period, but in most (17 of the 25 patients), the angle closure was nonacute (that is, no clinical signs or symptoms and no increase in intraocular pressure). None of the test factors studied showed a high sensitivity or positive predictive accuracy in detecting the eyes that later developed angle closure.

Topical timolol administration reduces the incidence of glaucomatous damage in ocular hypertensive individuals. A randomized, double-masked, long-term clinical trial (1)

OBJECTIVES

A randomized, double-masked, 5-year clinical trial was conducted to determine whether topical timolol therapy was more effective than placebo in delaying or preventing the onset of glaucomatous damage in moderate-risk ocular hypertensive subjects.

METHODS

One eye was chosen randomly to receive timolol therapy twice daily; the fellow eye received placebo (timolol vehicle). The primary end point of the study was reproducible visual field loss detected on three consecutive tests. Automated static threshold visual fields were added to the protocol as the study proceeded, and criteria for reproducible defects for the automated fields were developed. The secondary end point was progressive optic disc cupping confirmed by examination of stereoscopic disc photographs. Intraocular pressure was not used as an end point (i.e., eyes were not withdrawn from the study because they reached a predetermined level of intraocular pressure).

Ocular hypertension treatment study: design issues

This report relates the design and conduct considerations in the planning of a large, multicenter clinical trial on the treatment of ocular hypertension. This trial will begin patient enrollment in January 1994.

Trabeculectomy with releasable sutures

We attempted to reduce some of the postoperative complications of trabeculectomy by using releasable scleral flap sutures. This technique allows an initial tight closure of the scleral flap with the option to increase aqueous humor outflow in the early postoperative period. We reviewed our experience with trabeculectomy and releasable sutures in 146 eyes (134 patients) and compared these cases with a prior series of 128 eyes (124 patients) that underwent trabeculectomy with permanent scleral flap sutures. In the control group, 42 eyes (32.8%) had clinically detectable shallowing of the anterior chamber in the postoperative period. In contrast, shallow anterior chamber was noted in 21 eyes (14.4%) in the group with releasable sutures (P = .0003). Flat anterior chamber, defined as iridocorneal touch to the pupil margin, occurred in 11 control eyes (8.6%) but in only 2 eyes (1.4%) with releasable sutures (P = .0078). Surgical intervention to drain suprachoroidal fluid and re-form the anterior chamber was required in eight control eyes (6.2%) but in only one study eye (0.7%) (P = .014). At 1 year of follow-up, the two groups were similar in terms of mean intraocular pressure, the need for ocular hypotensive medications, and failure rate.

Gonioscopic ab interno laser sclerostomy. A pilot study in glaucoma patients

PURPOSE

The purpose of this study is to evaluate the safety and efficacy of gonioscopic ab interno laser sclerostomy (GLS) in patients with glaucoma.

METHODS

The technique of GLS involves iontophoresis of methylene blue dye (1%) at the limbus to focally dye the sclera and to provide subsequent delivery of 10-microsecond pulsed laser energy to the dyed area through a goniolens. The laser emits at 660 nm, a wavelength that is maximally absorbed by the methylene blue dye. Patients were evaluated for fistula formation, intraocular pressure (IOP) reduction, and adverse sequelae. Thirty-eight treatments were performed in 35 eyes.

RESULTS

Successful complete sclerostomies were achieved in 21 eyes (55%), which was associated with an acute mean reduction in IOP of 23 mmHg. Mean preoperative IOP for all patients was 35 mmHg, and 1 hour after treatment it was reduced to 18.5 mmHg. In 4 of the 38 treatments, there was no acute IOP reduction, and these eyes were judged as failures. The mean follow-up time was 8.2 months with a maximum follow-up of 15 months. By 9 months, 50% of patients had an IOP of 22 mmHg or lower. The number of antiglaucoma medications decreased from 3.1 to 1.7 for all eyes over the 15-month follow-up period. Hyphemas (13%) were the only major complication, and these resolved spontaneously. In only one case did the IOP increase after the procedure.

CONCLUSION

The results of this trial indicate that GLS is technically feasible, and preliminary results of IOP control are promising.

MK-507 versus sezolamide. Comparative efficacy of two topically active carbonic anhydrase inhibitors

Topical carbonic anhydrase inhibitors MK-507 and sezolamide hydrochloride (previously known as MK-417) were compared in a double-masked, randomized, placebo-controlled study in 82 patients with bilateral primary open-angle glaucoma or ocular hypertension. MK-507 was given every 8 or 12 hours, sezolamide every 8 hours, or placebo every 8 or 12 hours for 4 days. Both drugs lowered intraocular pressure (IOP) substantially. MK-507 was somewhat more active than sezolamide, with a peak mean IOP reduction of 26.2% for MK-507 versus 22.5% for sezolamide, although the difference between the treatments was not statistically significant. These drugs may have potential in the treatment of glaucoma.

Steady-state pattern electroretinogram following long term unilateral administration of timolol to ocular hypertensive subjects

To determine whether long-term reduction of intraocular pressure leads to a corresponding preservation of the pattern electroretinogram (PERG), PERGs were studied in 21 patients with ocular hypertension who had received unilateral timolol therapy for a minimum of 6 years. The mean difference in intraocular pressure (IOP) between the placebo-treated and the timolol-treated eyes (over 6 years) was 2.4 mm Hg. Steady-state PERGs (16.0 rps) were obtained simultaneously in both eyes of each patient, with four check sizes (0.25, 0.5, 1.0 and 2.0 degrees). Significant (p less than 0.05) steady-state PERG deficits (i.e., amplitude more than two standard deviations below the mean value of age-matched controls) were observed in 16 eyes of 12 patients (10 placebo-treated and 6 timolol-treated eyes). The mean PERG amplitude did not differ significantly between the placebo-treated and timolol-treated eyes. However, a significant correlation (r = -0.423) in the IOP differences between the placebo-treated and timolol-treated eyes and the corresponding PERG amplitude differences was noted in three of the four test conditions (i.e. 0.25, 0.5, and 1.0 degrees). These results suggest that reducing IOP may preserve ganglion cell function in some patients with ocular hypertension.

Transscleral neodymium: YAG laser cyclocoagulation for uncontrolled glaucoma

To determine the efficacy and safety of the procedure, we reviewed the records of 25 eyes of 25 patients who had received noncontact transscleral Nd:YAG laser cyclocoagulation for a variety of uncontrolled glaucomas. Thirteen to 35 pulses (mean, 22.7 pulses) had been placed 1 mm to 2 mm behind the limbus with an energy per pulse of 3.4 J to 8.2 J (mean 4.5 J). Follow-up ranged from 6 months to 23 months, with the exception of one eye, which had to be enucleated. Nine of the 25 eyes (36%) required one or two repeat treatments. Twelve (48%) had intraocular pressures at last follow-up of less than 21 mm Hg but greater than 4 mm Hg. Ten eyes (40%) developed moderate to severe pain transiently, and 10 (40%) developed substantial, but transient, inflammation. Transscleral Nd:YAG laser cyclocoagulation appears to be relatively effective and well tolerated.

MK-927: a topical carbonic anhydrase inhibitor. Dose response and duration of action

The dose response to a single topical administration of the carbonic anhydrase inhibitor MK-927 was investigated in 24 patients with primary open angle glaucoma or ocular hypertension. Three concentrations of MK-927 (2%, 1%, and 0.5%) and placebo were administered in a two-center, double-masked, randomized, placebo-controlled, four-period crossover study. MK-927 at the 0.5% concentration appeared to be minimally effective in reducing intraocular pressure. A single topical dose of 1% MK-927 resulted in a significantly greater percent reduction in intraocular pressure for up to 6 hours when compared with treatment with placebo. Similarly, a single dose of 2% MK-927 significantly lowered intraocular pressure for 8 hours compared with treatment with placebo. The pressure reduction from baseline measured 23.7% and 11.3% at 8 hours after instillation of a single drop of 2% MK-927. The medication was well tolerated and appeared to lower intraocular pressure in a dose-dependent fashion.

Topical timolol administration reduces the incidence of glaucomatous damage in ocular hypertensive individuals. A randomized, double-masked, long-term clinical trial

We conducted a randomized, double-masked, long-term clinical trial to determine whether topical timolol therapy was effective in delaying or preventing the onset of glaucomatous damage in moderate-risk ocular hypertensive subjects. In 62 patients, one eye was chosen randomly to receive timolol therapy twice daily while the fellow eye received placebo. During the course of the study, the mean +/- SD difference in intraocular pressure between the timolol-treated and the placebo-treated eyes was 2.3 +/- 2.6 mm Hg. Reproducible visual field loss developed in 4 timolol-treated eyes and 10 placebo-treated eyes. Progressive optic disc cupping was noted in 4 timolol-treated and 8 placebo-treated eyes. Using a computerized image analysis system, the mean +/- SD increase in optic disc pallor during the course of the study was 0.86% +/- 2.4% in the timolol-treated eyes as opposed to 1.80% +/- 3.6% in the placebo-treated eyes. This study provides evidence that lowering intraocular pressure by medical treatment reduces the incidence of glaucomatous damage in ocular-hypertensive individuals.

Timolol treatment prevents or delays glaucomatous visual field loss in individuals with ocular hypertension: a five-year, randomized, double-masked, clinical trial

A 5-year, randomized, double-masked, clinical trial was conducted to determine whether treatment with topical timolol maleate was effective in preventing or delaying the onset of glaucomatous visual field loss in subjects with ocular hypertension. Sixty-five individuals considered to be at moderate risk for developing open-angle glaucoma were recruited for the study. In each patient, one eye was chosen randomly to receive timolol twice-daily while the fellow eye received diluent (placebo). Timolol administration reduced IOP from baseline in the treated eyes over the course of the study by a mean +/- SD of 4.9 +/- 3.4 mm Hg. Timolol administration also produced a mean +/- SD contralateral reduction of IOP from baseline in the untreated fellow eyes of 2.9 +/- 3.1 mm Hg. The mean +/- SD difference in IOP between the treated and untreated eyes during the study was 2.3 +/- 2.6 mm Hg. Over the course of the study reproducible visual field loss developed in 4 timolol treated eyes and 10 placebo treated eyes (P = .039, McNemar test). Clinical progressive optic disc cupping was noted in four treated and eight untreated eyes (P = .11, McNemar test). In the 42 subjects who completed a minimum 4-year follow-up, baseline and final optic disc photographs were analyzed using a computer image analysis system to determine changes in the area of disc pallor. The mean +/- SD increase in optic disc pallor was 0.86% +/- 2.4% in the timolol treated eyes and 1.80% +/- 3.6% in the placebo treated eyes. This difference was statistically significant (P = .04, paired t-test). This study provides evidence that medical treatment prevents or delays the onset of glaucomatous visual field loss and optic disc damage in individuals with ocular hypertension. The magnitude of the protective effect of timolol was partially obscured by the contralateral reduction of IOP in the placebo treated fellow eyes.

Intraocular pressure response to topical dexamethasone as a predictor for the development of primary open-angle glaucoma

In a retrospective study we reviewed the records of 788 subjects who had been corticosteroid tested with 0.1% dexamethasone four times daily to one eye for six weeks. All subjects had normal kinetic visual fields and optic nerve heads in both eyes at the time of testing and were followed up for a minimum of five years. Some subjects had normal baseline intraocular pressures whereas others were considered to have ocular hypertension. Of 276 individuals who were high corticosteroid responders (intraocular pressure greater than 31 mm Hg during dexamethasone administration), 36 (13.0%) developed glaucomatous visual field loss during the follow-up period. Only nine of 261 individuals (3.4%) who were intermediate responders (intraocular pressure 20 to 31 mm Hg during dexamethasone administration) and none of 251 individuals who were low responders (intraocular pressure less than 20 mm Hg during dexamethasone administration) developed glaucomatous visual field loss. However, the ability of the intraocular pressure response to dexamethasone to predict the development of glaucomatous visual field loss was not as good as the predictive power of a multivariate model that included patient age, race, baseline intraocular pressure, baseline outflow facility, baseline cup/disk ratio, and systemic hypertension.

Compliance with topical timolol treatment

To determine if compliance with timolol treatment was better than compliance with pilocarpine treatment (as reported previously), we measured compliance with timolol treatment in a sample of 110 patients using an unobtrusive eyedrop medication monitor, which recorded electronically the date and time of each drug administration over a four- to six-week period. The patients administered a mean +/- S.D. of 82.7% +/- 19.0% of the prescribed timolol doses (range, 20% to 100%). Forty-five patients were treated concurrently with timolol and pilocarpine. These patients administered a mean +/- S.D. of 84.3% +/- 14.0% of the prescribed timolol doses and 77.7% +/- 18.7% of the prescribed pilocarpine doses (P = .012, van der Waerden test). Our results suggest that while compliance is influenced by the drug regimen, defaulting is not eliminated by prescribing a more convenient medication with fewer side effects.

Compliance with topical pilocarpine treatment

Using an unobtrusive eyedrop medication monitor, we measured compliance with topical pilocarpine treatment in a sample of 184 patients. The eyedrop monitor recorded electronically the date and time of each pilocarpine administration over a four- to six-week period. The subjects administered a mean +/- S.D. of 76.0% +/- 24.3% of the prescribed pilocarpine doses. Eleven patients (6%) took less than one quarter and 28 patients (15.2%) took less than one half of the prescribed administrations. In contrast, when the subjects were interviewed they reported taking a mean +/- S.D. of 97.1% +/- 5.9% of the prescribed pilocarpine doses. As determined by the monitor, 45 patients (24.5%) had at least one day per month with no administrations of pilocarpine; 56 subjects (30.4%) compressed the doses during the daytime hours, leaving an interval between the night dose and the morning dose the next day of 12 hours or more. The rate of compliance was significantly higher (P less than .0001) in the 24-hour period preceding the return appointment than in the entire observation period.

Can ophthalmologists correctly identify patients defaulting from pilocarpine therapy?

We determined whether clinical measurements and assessments available to ophthalmologists could be used to identify patients who default from pilocarpine treatment. The measurements and assessments included intraocular pressure, pupillary diameter, pupillary reactivity to light, the patient's report of compliance, the physician's prediction of compliance, the patient's log of pilocarpine administration, and the weight of pilocarpine eyedrops utilized. Compliance with the pilocarpine regimen was measured with an unobtrusive eyedrop medication monitor. Intraocular pressure and pupillary diameter did not correlate with compliance to the regimen as measured by the eyedrop monitor. Pupillary reaction to light, the physician's prediction of compliance, a daily log of pilocarpine administration, the weight of pilocarpine utilized, and the patient's report of compliance correlated modestly with compliance as measured by the monitor (range of correlations, 0.19 to 0.24). However, none of these measures taken by itself or combined in any manner adequately distinguished patients with lower rates of compliance from those with higher rates of compliance. At present, the eyedrop monitor is the only reliable method for detecting patients who default from treatment.

Acute intraocular pressure response to argon laser iridotomy

Argon laser iridotomy (ALI) was performed in 50 eyes for prophylactic treatment of anatomically narrow iridocorneal angles and in 50 eyes for therapy of chronic angle-closure glaucoma. Intraocular pressure was increased 6 mmHg or more 1 to 2 hours after ALI in 19 of 50 eyes with anatomical narrow iridocorneal angles and in 23 of 50 eyes with chronic angle-closure glaucoma. Increases greater than 20 mmHg over baseline value occurred in 5 of 50 eyes with narrow iridocorneal angles and in 7 of 50 eyes with chronic angle-closure glaucoma. A clinically significant increase in intraocular pressure (defined as a pressure 30 mmHg or greater and 40% or more increased over the pre-laser value) occurred 1 to 2 hours after ALI in 11 of 50 eyes with narrow iridocorneal angles and in 17 of 50 eyes with chronic angle-closure glaucoma. There was no statistical difference (chi square P greater than 0.3) in the incidence of this complication in the two groups. Additional medical therapy was effective in lowering the acute laser-induced elevation in intraocular pressure. Patient diagnosis, patient demographics, preoperative glaucoma medication and laser treatment parameters did not predict which eyes would develop this complication. Eyes which did not have a clinically significant elevation in intraocular pressure 1 to 2 hours after ALI did not show a later increase at 24 hours.

A miniature compliance monitor for eyedrop medication

We developed an eyedrop medication monitor that electronically records the date and time of each medication administration over a six-week period. It records a medication usage in a 15-minute interval when the cap is removed from the bottle and the bottle is inverted. The electronic components housed inside the bottle weigh 7.5 g, including the batteries, and the total volume of the circuit is 7.5 cc. The monitor resembles commercially available 30-mL eyedrop bottles in size, shape, and weight. The monitor is accurate when tested against known patterns of usage. The electronic eyedrop monitor should be useful in assessing compliance with eyedrop medications.

Intraocular pressure the day of argon laser trabeculoplasty in primary open-angle glaucoma

Argon laser trabeculoplasty was performed in one eye of 57 phakic patients with primary open-angle glaucoma. The eyes received a mean of 78 +/- 7 treatments over 360 degrees to the anterior trabecular meshwork. The power was titrated to produce blanching without bubble formation. Increased intraocular pressure (range +1 to +22 mmHg) occurred in 30 of the 57 (53%) eyes 1 hour after treatment. Eight (14%) of these eyes had a clinically significant elevation defined by all of three criteria: (1) an intraocular pressure greater than 30 mmHg, (2) greater than a 30% increase over the mean prelaser intraocular pressure, and (3) greater than a 10 mmHg increase over the peak prelaser diurnal intraocular pressure curve. These eight patients received either oral glycerine or acetazolamide. A rebound increase in intraocular pressure requiring repeat medical treatment occurred in four of the eight eyes. Two additional eyes without a pressure elevation 1 hour after treatment showed a later elevation. This was first detected 4 hours postoperatively in one eye and 7 hours after treatment in another eye. The 1-hour postoperative measurement detected most patients with clinically significant increased intraocular pressure (8 of 10 eyes) but these required continued observation for rebound increases. Patients with advanced glaucomatous visual field loss should also be followed closely to detect late increases in intraocular pressure (2 of 10 eyes).

When to treat ocular hypertension

Ocular hypertension (intraocular pressure greater than or equal to 21 mm Hg, normal visual fields, normal optic discs, open angles, and the absence of any contributing ocular disease) occurs in 4-10% of the population over age 40. The question of whether to treat ocular hypertensive patients remains controversial. The author recommends prophylactic treatment for selected ocular hypertensive individuals who are at high risk of developing primary open angle glaucoma. The primary risk factors are high intraocular pressure, optic disc abnormality, increasing age, a family history of glaucoma, and systemic vascular disease. In addition, certain features of the patient's personality or medical condition favor treatment; for instance, treatment would probably be indicated in (1) a young patient, (2) a one-eyed patient, (3) an unreliable patient, (4) a patient who cannot do reliable visual fields or in whom the optic disc cannot be visualized, (5) a patient who prefers to be treated, and (6) a patient who has suffered a retinal vascular occlusion.

Efficacy of combining timolol with other antiglaucoma medications

The ocular hypotensive effects of timolol and a carbonic anhydrase inhibitor (acetazolamide or methazolamide) are partially additive; that is, concurrent administration of these drugs produces a clinically useful reduction in intraocular pressure which is greater than the effect of either medication alone, but less than the arithmetic sum of the effects of the individual drugs. Similarly, concurrent administration of timolol and a miotic agent (pilocarpine, carbachol, or echothiophate iodide) produces a clinically useful response in most glaucoma patients. In contrast, the ocular hypotensive effects of timolol and epinephrine are poorly additive. Only a minority of patients maintain a substantial, longterm reduction in intraocular pressure when timolol is added to a regimen of epinephrine or vice versa. Ophthalmologists prescribing timolol or epinephrine for patients receiving the other drug are urged to use a therapeutic trial to one eye for several weeks to determine the efficacy of concurrent treatment. The addition of timolol to the medical regimen of patients uncontrolled on maximum tolerated antiglaucoma therapy (a miotic agent, epinephrine and a carbonic anhydrase inhibitor) reduces intraocular pressure substantially in one-third to one-half of the cases.