Pigment liberation test in open-angle glaucoma

The Short-Term Effect of 1% Tropicamide Drop on Pupillary Diameter and Intraocular Pressure Change in Patients With Pseudoexfoliation Material

PRCIS

In this study, in patients with pseudoexfoliation syndrome (PXS) or glaucoma, changes in intraocular pressure (IOP) and pupil size after 1% tropicamide used for pupil dilation, compared with healthy patients were quantitatively demonstrated up to 4 hours after dilation.

PURPOSE

The purpose of this study was to evaluate pharmacological dilatation with one drop of 1% tropicamide on pupillary diameter and IOP changes in patients with PXS and glaucoma (PXG).

MATERIALS AND METHODS

Eighty-two patients with PXS, 78 Patients with PXG, and 35 healthy subjects were included in the study. PXG and PXS were diagnosed based on IOP assessment, corneal pachymetry, optic disc examination, visual field testing, and peripapillary retinal nerve fiber analysis. IOP and the diameter of pupil size were measured before dilatation and at postdilatation first, second, and fourth hours.

RESULTS

The mean pupillary diameter values at postdilatation second and fourth hours were statistically significantly different between the patients with PXS and PXG ( P <0.001, for each). Also, there were significant differences between the PXS group and the control group in terms of the mean pupillary diameter values at predilatation and postdilatation at the first hour and postdilatation second hour ( P =0.007, <0.001, respectively). The mean pupillary diameter at all times was statistically significantly different between PXG and control groups ( P <0.001 for each). Significant IOP increases were observed in all groups after dilatation. The mean IOP at predilatation and postdilatation fourth hour was statistically significantly different between PXG and PXS groups ( P =0.042, <0.001, respectively). Whereas the mean IOP at predilatation, postdilatation first hour, postdilatation second hour, and postdilatation fourth hour were statistically significantly different between PXG and control group ( P <0.001 for each).

CONCLUSIONS

Significant IOP increases have been observed in our study with 1% tropicamide in the PXG and PXS groups, with the peak effect at the second hour in the postdilatation period. Furthermore, the mean pupil diameter was found to be significantly lower in PXG patients compared with the control group.

Changes of intraocular pressure and refractive status in children following cycloplegic refraction with 1% cyclopentolate and 1% tropicamide

PURPOSE

To evaluate the effect of cycloplegic mydriasis with 1% cyclopentolate and 1% tropicamide on the intraocular pressure (IOP) and refractive status of children for cycloplegic refraction and compare the [OP and refractive changes between hyperopic and myopic groups.

METHODS

This study was designed as a retrospective cohort study. Ninety one children received cycloplegic mydriasis. The IOP was measured with a noncontact tonometer before cycloplegic administration. One drop of 1% cyclopentolate was administered, which was followed by two drops of 1% tropicamide at an interval of 10 minutes. The IOP was then measured 30 minutes after tropicamide instillation. Autorefraction was assessed with an autorefractometer before and after cycloplegic mydriasis.

RESULTS

The mean age of the 44 girls and 47 boys was 7.3 ± 2.4 years. The mean precycloplegic IOP was 14.45 ± 2.47 mmHg and the mean postcycloplegic IOP was 15.06 ± 3.08 mmHg in all eyes. A significant difference was noted in the IOP change (p = 0.033). In the 39 hyperopic eyes, the mean precycloplegic IOP and postcycloplegic IOP were 14.54 ± 2.53 mmHg and 15.69 ± 3.35 mmHg, respectively. There was a significant difference in the IOP change (p = 0.008). In the 52 myopic eyes, the mean precycloplegic IOP and postcycloplegic IOP were 14.38 ± 2.44 mmHg and 14.61 ± 2.80 mmHg, respectively (p = 0.72). There was no significant IOP change in the myopic group. The postcycloplegic IOP was significantly different between the hyperopic and the myopic groups (p = 0.021). Three eyes (3.3%) had an IOP elevation more than 5.0 mmHg after cycloplegic mydriasis. Postcycloplegic refraction showed significant hyperopic shifts in all eyes (p < 0.0001).

CONCLUSION

Cycloplegic mydriasis with 1% cyclopentolate and 1% tropicamide caused IOP changes in preschool and school-aged children with hyperopia. Ophthalmologists should be very cautious in monitoring IOP changes for children with cycloplegic medication use.

Changes in intraocular pressure after pharmacologic pupil dilation

Background

Intraocular pressure (IOP) may vary according to the change of ocular conditions. In this study, we want to assess the effect and mechanism of pupil dilation on IOP in normal subjects.

Methods

We prospectively evaluated 32 eyes of 32 patients (age; 61.7 ± 8.2 years) with normal open angles under diurnal IOP. IOP was measured every two hours from 9 AM to 11 PM for one day to establish baseline values and was measured again for one day to assess the differences after dilation. To induce dilation, we administered 2.5% phenylephrine and 1% tropicamide every 5 minutes from 8:30 AM to 8:45 AM and for every two hours from 11 AM to 9 PM to keep the pupil dilated. Diurnal IOP, biometry, Visante OCT, and laser flare photometry were measured before and after dilation.

Results

We observed a significant increase in IOP after dilation, 1.85 ± 2.01 mmHg (p = 0.002). IOP elevation remained significant until about four hours after dilation. Thereafter, IOP decreased slowly and eventually reached pre-dilation level (p > 0.05). Flare values decreased, and the anterior chamber angle became wider after mydriasis.

Conclusions

Dilation of the pupil significantly and incidentally elevated IOP in normal subjects. Further related studies are warranted to characterize the mechanism of the increased IOP after dilation.

The amount of intraocular pressure rise during pharmacological pupillary dilatation is an indicator of the likelihood of future progression of glaucoma

AIM

To determine if there is a relationship between the amount of increase in IOP following dilatation with a cycloplegic agent and the future course of glaucoma.

METHOD

A retrospective chart review of 100 eyes from 55 subjects with open-angle glaucoma who had had IOP measured before and after pharmacological pupillary dilatation was performed to establish the rate of progression of glaucoma, based on serial evaluation of the visual fields using the glaucoma staging system 2 (GSS 2), and optic discs using the disc damage likelihood scale (DDLS). Progressive visual field loss was defined as an increase of two or more stages with the GSS 2 and progressive deterioration of the disc was defined as an increase of two or more stages with the DDLS. Mean follow-up time was 7.2 years.

RESULTS

A total of 26 eyes showed glaucomatous progression. The likelihood of progression of glaucoma was related to the amount of IOP increase after pharmacological pupillary dilatation. For every 1 mmHg increase in IOP, the odds of progression increased 24% (p = 0.008). The likelihood of progression of glaucoma, however, was not related to the baseline IOP, which was 20.63 mmHg (SD = 4.59 mmHg) in those showing deterioration of disc or field and 19.72 mmHg (SD = 5.32 mmHg) in those not worsening according to our definition.

CONCLUSION

In patients with open-angle glaucoma, the amount of increase in IOP caused by pharmacological pupillary dilatation is related to the likelihood of future progression of glaucoma.

Exfoliation syndrome

Exfoliation syndrome (XFS) is an age-related disease in which abnormal fibrillar extracellular material is produced and accumulates in many ocular tissues. Its ocular manifestations involve all of the structures of the anterior segment, as well as conjunctiva and orbital structures. Glaucoma occurs more commonly in eyes with XFS than in those without it; in fact, XFS has recently been recognized as the most common identifiable cause of glaucoma. Patients with XFS are also predisposed to develop angle-closure glaucoma, and glaucoma in XFS has a more serious clinical course and worse prognosis than primary open-angle glaucoma. There is increasing evidence for an etiological association of XFS with cataract formation, and possibly with retinal vein occlusion. XFS is now suspected to be a systemic disorder and has been associated preliminarily with transient ischemic attacks, stroke, systemic hypertension, and myocardial infarction. Further ramifications await discovery. Deposits of white material on the anterior lens surface are the most consistent and important diagnostic feature of XFS. The classic pattern consists of three distinct zones that become visible when the pupil is fully dilated. Whereas the classic picture of manifest XFS has been often described, the early stages of beginning exfoliation have not been well defined. Next to the lens, exfoliation material is most prominent at the pupillary border. Pigment loss from the iris sphincter region and its deposition on anterior chamber structures is a hallmark of XFS. Despite extensive research, the exact chemical composition of exfoliation material (XFM) remains unknown. An overproduction and abnormal metabolism of glycosaminoglycans have been suggested as one of the key changes in XFS. The protein components of XFM include both noncollagenous basement membrane components and epitopes of the elastic fiber system such as fibrillium. Regardless of etiology, typical exfoliation fibers have been demonstrated electron microscopically in close association with the pre-equatorial lens epithelium, the nonpigmented ciliary epithelium, the iris pigment epithelium, the corneal endothelium, the trabecular endothelium, and with almost all cell types of the iris stroma, such as fibrocytes, melanocytes, vascular endothelial cells, pericytes, and smooth muscle cells. The presence of XFS should alert the physician to the increased risks of intraocular surgery, most commonly zonular dehiscence, capsular rupture, and vitreous loss during cataract extraction. Heightened awareness of this condition and its associated clinical signs are important in the detection and management of glaucoma, and preoperative determination of those patients at increased risk for surgical complications.

The amount of lens exfoliation and chamber-angle pigmentation in exfoliation syndrome with or without glaucoma

Correlations of the amount of chamber-angle pigmentation and exfoliation material with IOP and with image analysis of the optic discs are reported in the paired eyes of 63 persons with unilateral exfoliation syndrome, and 35 patients with unilateral capsular glaucoma. The effect on IOP of phenylephrine-induced pigmentary dispersion is examined. Chamber-angle pigmentation was more pronounced in capsular glaucoma than in the nonglaucomatous exfoliation eyes (p < 0.01), although the amount of lens exfoliation was the same. In nonglaucomatous exfoliative eyes IOP correlated significantly with the amount of chamber-angle pigmentation (p < 0.01) and exfoliation material (p < 0.05). The nonglaucomatous exfoliative eyes with grade > or = 2 trabecular pigmentation and those with reduction of IOP on phenylephrine provocation had smaller rim areas and rim/disc area ratios than the fellow eyes (p < 0.05). Rather than the amount of exfoliation, the main risk factor for glaucoma seems to be the degree of chamber-angle pigmentation.

The cyclopentolate provocative test in suspected or untreated open-angle glaucoma. V. Statistical analysis of 431 eyes

The mydriasis provocative test with 1% cyclopentolate (CPT) was performed on 431 eyes with suspected or untreated open-angle glaucoma. Tonography was performed both before and during CPT to study the changes in aqueous dynamics during the test. Statistical analysis of the results yielded the following mean trends and correlations at a highly significant level (P less than 0.001) in the alterations: Intraocular pressure (IOP) rose (deltaP +/- SD) (+ 1.4 +/- 2.9 mmHg) and aqueous outflow facility decreased (deltaC) (-10%) during CPT. The distribution of deltaP and deltaC did not follow the normal Gaussian distribution. The change in deltaP deviated from the Gaussian distribution in 5-10% of the eyes. The deviating values concur with those of the responder eyes in which IOP rose greater than or equal to 8 mmHg during CPT. deltaP was linearly dependent on the initial IOP level Po and the absolute change was always almost constant, approximately +1.4 mmHg. Both the total series and the responder eyes displayed the same trend for the change in aqueous outflow facility in relation to the initial C value (Co): low Co values changed less on average and high Co values changed more and diminished. It is not known why the deltaC change was different depending on the Co value. The change in IOP correlated statistically highly significantly in the initial C value (Co). The loqwe the Co value, the higher was the mean IOP elevation during CPT. In contrast, the change in aqueous outflow (deltaC) did not corrrelate (N.S.) with the initial IOP level (Po) before CPT.

The cyclopentolate provocative test in suspected or untreated open-angle glaucoma. IV. Fluorescein angiography of the vessels of the iris in open-angle glaucoma eyes with a positive cyclopentolate response

Fluorescein angiography of the iris (IFAG) was performed on 15 patients with a positive cyclopentolate response (IOP elevation greater than or equal to 8 mmHg) in 17 eyes to the cyclopentolate provocative test. The chamber angles were open in all the eyes. Seven of the responder eyes had capsular glaucoma undergoing treatment, six had simple glaucoma, two had pigmentary glaucoma and two suspicion of open-angle glaucoma. The object was to study with IFAG whether vascular changes can be established in the iris of the responder eyes such as could have a role in the elevation of IOP. All the eyes with capsular glaucoma displayed vascular changes, vasoproliferation and fluorescein leakage from the iris vessles. No other vascular changes were seen in the irises of the responder eyes. IFAG revealed no differences in the iris vasculature between responder and non-responder eyes. A vascular aetiology for the IOP elevation in responders is improbable.

The cyclopentolate provocative test in suspected or untreated open-angle glaucoma. III. The significane of pigment for the result of the cyclopentolate provocative test in suspected or untreated open-angle glaucoma

Significant elevations of IOP, i. e. responses, occurred in eyes with suspected or untreated open-angle glaucoma during the mydriasis test with 1% cyclopentolate (CPT). The possible role of pigment in the IOP elevations seen in the responders was studied. Pigment was liberated in the aqueous, sometimes very profusely, in 88 (31.9%) of 276 eyes during CPT. The maximal IOP elevations, ad 20 mmHg, were seen in just these eyes. They were eyes with capsular or pigmentary glaucoma or eyes in which exceptionally heavy pigment was demonstrated in the chamber angle for other reasons. There was a statistically significant correlation between pigment liberation and IOP elevation during CPT. Evidently profuse pigment liberation may have caused transient blocking of the trabecular meshwork, obstruction of aqueous outflow and elevation of IOP. Liberation of pigment in the aqueous during CPT was statistically highly significantly more profuse in eyes with pseudoexfoliation than in eyes without pseudoexfoliation. An equally significant correlation with demonstrated between the grade of chamber angle pigmentation and the degree of pigment liberation during CPT. The significance of pigment for IOP elevation was seen also in the statistically highly significantly more profuse pigmentation of the chamber angle in the responder than in the non-responder eyes.

The cyclopentolate provocative test in suspected or untreated open-angle glaucoma. I. Effect on intraocular pressure

The mydriasis provocative test with 1% cyclopentolate (CPT) was performed on 218 patients with suspected or untreated open-angle glaucoma, on 431 eyes in all. Gonioscopy was performed before and during the test to ensure that te chamber angles were open throughout. The effect of cyclopentolate on intraocular pressure (10P) in these eyes is reported in the present paper. The mean change in IOP (+/-SD) During CPT was +2.5 +/- 3.1 mmHg in the glaucoma group (196 eyes), +0.4 +/- 2.5 mmHg in the group with suspicion of open-angle glaucoma (235 eyes), and +1.4 +/- 2.9 mmHg in the total series. The difference in IOP change between the groups with glaucoma and suspected glaucoma is statistically highly significant. The incidence of positive responses (IOP rise larger than or equal to 8 mmHg) in the glaucoma group (8.7%: 17 eyes) was significantly higher than in the suspicion group (1.7%: 4 eyes). Significant IOP elevations in the total series were demonstrated in 21 eyes of 18 patients (4.9%). Including the borderline cases, IOP elevations larger than or equal to 5 mmHg were also significantly more frequent in eyes with glaucoma (24.0%: 47 eyes) than in eyes with suspected glaucoma (11.9%: 28 eyes). The occurrence and magnitude of positive responses were not dependent on the initial IOP level. Further analysis of the responder group and clinical studies of the mechanism of IOP elevation on the same patients are presented in parts II and III.

The cyclopentolate provocative test in suspected or untreated open-angle glaucoma. II. Clinical studies on the mechanism of intraocular pressure elevations

The mydriasis provocative test with 1% cyclopentolate (CPT) was performed on 218 patients with suspected or untreated open-angle glaucoma, on 431 eyes in all. Significant IOP elevations (larger than or equal to 8 mmHg) were demonstrated in 21 eyes of 18 patients. The present paper analyses the responder group and presents some other investigation results and clinical findings to throw additional light on the mechanism of IOP elevation in responders. The responders did not differ from the other patients of the material in age or sex. Patients with capsular glaucoma constituted the biggest group among the responders. 48% of the significant IOP elevations during CPT were encountered in eyes with pseudoexfoliation (PE) and open-angle glaucoma. A positive response during CPT was statistically significantly more common in PE eyes than in eyes without PE. Capsular glaucoma was diagnosed immediately or later in all PE eyes which displayed a larger than or equal to 5 mmHg IOP elevation during the CPT. In addition to the importance of pigment in PE eyes, PE material may play a certain role in the elevation of IOP . The mechanism of this role is not known. No correlation was established between the results of the water drinking test and the CPT. The mechanism that causes the elevation of IOP must be quite different in these two tests. Nor was a statistically significant difference observed in the incidence of cataract, the maximal variation of IOP in the 48-h tension curve, the occurrence of cupping of the optic disc or visual field defects between the responder and non-responder eyes in the glaucomatous group.