Rise In IOP Research Articles

Improvement in open-angle glaucoma by nocturnal home haemodialysis

Open-angle glaucoma (OAG) is a common ocularabnormality seen in patients with end-stage renaldisease (ESRD) [1]. Although the pathogenesis ofOAG is not yet fully understood, lowering intraocularpressure is the accepted treatment goal. Withoutadequate treatment, glaucoma can lead to visualdisability and eventual blindness [2].From a simplified viewpoint, intraocular pressure isdetermined by the balance between aqueous produc-tion from the ciliary body and drainage of the aqueoushumour through the trabecular meshwork. Normalintraocular pressure (IOP) ranges from 10 to21mmHg. IOP of 20–30mmHg usually results inchronic optic nerve damage. In cases of significantintraocular hypertension (40–50mmHg), rapid visualloss and retinovascular occlusion may occur.Intradialytic alteration of IOP by conventionalhaemodialysis (CHD) has been well-documented[3,4]. It is generally accepted that there are twoopposing forces, which may impact on IOP duringhaemodialysis: ultrafiltration and solute removal.Tokuyama et al. [3] documented a fall in IOP whichwas inversely correlated with the increase in plasmaoncotic pressure caused by ultrafiltration. In contrast,other authors speculated that the rapid removal ofuraemic toxins via CHD may lower plasma osmolalityat a rate in excess of changes in ocular osmolalityresulting in an acute rise in IOP [5].Nocturnal haemodialysis (NHD), which provides8–10h of renal replacement therapy during sleep,5–7 nights per week, is a form of intensive haemo-dialysis which approximates most closely to normalphysiology [6]. Here, we report our index case inwhich the conversion from CHD to NHD is associatedwith a restoration in IOP. We will further examinethe potential interactions between augmentation ofuraemia clearance, enhanced volume control andchanges in total peripheral resistance in the treatmentof glaucoma with NHD in ESRD patients.

Ocular Hypertensive Response to Topical Dexamethasone Ointment in Children

PurposeTo investigate the rate and the degree of the ocular hypertensive response to dexamethasone ointment in children undergoing eyelid surgery.MethodsDexamethasone ointment (Dexcosil®) was applied three times a day for the first week and twice a day for the second to third week postoperatively to children undergoing epiblepharon surgery. Intraocular pressure (IOP) was measured on the day before surgery, postoperative day 1, 7, 14, 21, 28 and 2 weeks thereafter until the IOP reached preoperative levels. Peak IOP, IOP net increase and time to reach a peak IOP were analyzed. Dexamethasone ointment was discontinued if the IOP was 25 mmHg or more.ResultsA total of 96 children (mean age, 6.5±2.7 years) were included. Preoperative mean IOP was 13.6±2.9 mmHg (range 7-19). After dexamethasone ointment treatment, the children showed a significant rise in IOP as compared with the preoperative values. The peak IOP was 20.6±4.9 mmHg (range 11-39) and the time to reach peak IOP was 8.5±5.9 days. The low responders (delta IOP ≤5 mmHg) of our group comprised 35.4% (34/96) of patients, intermediate responders (delta IOP 6-15 mmHg) comprised 56.3% (54/96) of patients and high responders (delta IOP≥16) comprised 8.3% (8/96) of patients. A net increase in IOP was significantly higher in children 5 years old or less as compared with those older than 5 years (age ≤5, 9.4±7.5 mmHg vs age >5, 6.3±4.4 mmHg; p=0.015, unpaired t-test).ConclusionsOcular hypertensive response after dexamethasone ointment to the eyelids occurred frequently in children, especially those 5 years old or younger.

Augeninnendruck und Notwendigkeit einer Parazentese unmittelbar nach intravitrealer Triamcinolon-Injektion

Intravitreal triamcinolone injection (IVT) has become a treatment option for macular edema of heterogeneous etiology and neovascular retinal diseases including AMD. Besides the risk for a steroid-induced secondary open-angle glaucoma, the acute rise in intravitreal volume induces IOP elevations immediately after injection. To decrease the intravitreal volume a paracentesis is advocated by many surgeons. The aim of this study was to determine variations in IOP at different time points immediately after IVT in order to assess the necessity for routine paracentesis. The IOP was recorded by Goldmann applanation tonometry preoperatively, 10 minutes, 1, 3 and 24 hours after intravitreal injection of 0.1 mL (4 mg) triamcinolone. A consecutive series of 32 eyes of 32 patients with diabetic macular edema, diffuse edema after central vein occlusion or occult subfoveal choroidal neovascularization due to age-related macular degeneration was included. Statistical analysis was performed with ANOVA test and Bonferroni correction. Compared to baseline (15.24 +/- 0.52 mm Hg) IOP was significantly elevated 10 min postoperatively (22.28 +/- 1.4 mmHg; p < 0.05). One hour after injection IOP decreased to 15.58 +/- 0.69 mmHg (p < 0.05). Three and 24 h after injection mean IOP was not significantly different from preoperative baseline levels. Immediately after IVT light perception was tested and retinal perfusion was evaluated by indirect ophthalmoscopy. In none of the patients was a paracentesis necessary. Intravitreal injection of 0.1 mL triamcinolone led to a moderate transient rise in IOP. Based on these results, a routinely performed paracentesis immediately before or after IVT is not required. As paracentesis bears an additional risk including endophthalmitis it should only be considered if functional testing following injection indicates a relevant impairment of retinal perfusion.

Intraocular pressure rise after phacoemulsification surgery in glaucoma patients

Reply: Drs. Liu and coauthors raise an important question about the short-term changes in IOP after phacoemulsification surgery in eyes with OAG.1 Our study demonstrated that the IOP increased transiently from 1 to 3 days after phacoemulsification surgery, but then gradually decreased. Furthermore, a marked rise in IOP to 30 mm Hg or more occurred the day after surgery in approximately 13% of OAG eyes. Liu and coauthors suggest that the increase in IOP shortly after surgery might be due to withdrawal of antiglaucoma drugs. However, several previous studies show that the IOP gradually decreases for several weeks after cataract surgery2–4; more recent studies report a transient rise in IOP in the early postoperative days in glaucomatous eyes as well as in eyes without glaucoma.5,6 Furthermore, it is well known that an early IOP elevation occurs in a certain percentage of glaucoma patients,7 so our results are consistent with those in previous studies. The transient increase in IOP does not appear to be due to the withdrawal of antiglaucoma medications. The IOP-reducing effect of ß-blockers is known to last for 2 weeks after cessation,8 and in the article by Linden and coauthors9 cited by Liu and coauthors, the effect of latanoprost is shown to be substantial for at least 1 week after cessation. Based on these studies, it is improbable that the IOP increases suddenly the day after withdrawal. We believe the IOP elevation immediately after surgery is related to deterioration of the outflow facility due to minimum residual cortex, inflammatory cells, and, possibly, residual ophthalmic viscosurgical device. When we examine the IOP in the patients who received and those who did not receive antiglaucoma drugs before surgery, we find no significant difference in the mean IOP throughout the period of follow-up (Table 1). In addition, the mean decrease in IOP from the preoperative level was similar in the 2 groups. Furthermore, the marked increase in IOP occurred in 3 (12%) of the 25 eyes that received antiglaucoma drugs and in 1 (14.2%) of the 7 eyes that did not; this occurrence was not significantly different using the survival analysis (P=.8736). These results indicate that the increase in IOP seen in the early postoperative period was not related to withdrawal of antiglaucoma medications.Table 1: Comparison of mean IOP and decrease in IOP between the group that received antiglaucoma medications before surgery and the group that did not.Hitoshi Yasutani MD Ken Hayashi MD Hideyuki Hayashi MD Fumihiko Hayashi MD

Ocular Irritation Following Frequent Applications of Cyclosporinea

ABSTRACTPurpose. Previous studies have shown that repetitive administrations of Cyclosporine A (CsA) eye drops to the rabbit eye caused a long-lasting miosis, accompanied by conjunctival hyperemia, anterior humor flare, and fibrin formation in the anterior chamber. The aim of the present study was to clarify the mechanism of these findings. Methods. One drop of 0.1% CsA eye drops was applied once or six times every 30 minutes for 2.5 hours. The eyes were examined by slit-lamp microscope, and IOP and anterior humor flare were measured prior to the studies and at 0, 1, 3, 6, 12, and 24 hours after administration of CsA or vehicle. While anterior chamber aqueous flare was increasing, aqueous humor and anterior segment of the eye were taken and analyzed. The entry of plasma proteins into the aqueous humor was studied by using Evans blue dye. Result. Conjunctival hyperemia, anterior humor flare and IOP rise miosis and fibrin formation in the anterior chamber were shown after six CsA administration ipsilaterally during 1–12 hours after the final administration. All of these observations were inhibited by pretreatment of indomethacin. While miosis was appearing, Evans blue dye penetrated the nonpigmented layer of the ciliary epithelium and the iris vessels. Calcitonin gene-related peptide (CGRP) was detected (184.1 ± 84.6 pg/mL), and CsA levels (891.6 ± 153.0 ng/mL) in anterior uvea exceeded the trough level. Conclusions. These results suggest that CsA can cause disruption of the blood-aqueous barrier with leaking from vessels in the ciliary processes and the iris, which are probably secondary effects of the irritation response releasing CGRP.

Early rapid rise in intraocular pressure after intravitreal triamcinolone acetonide injection

Purpose To report the occurrences of early rapid increases in intraocular (IOP) after intravitreal glucocorticoid injection. Design Observational case series. Methods We retrospectively reviewed the records of three patients seen and treated at Duke Eye Center. Results In all three cases, a significant rise in IOP occurred within 1 week of intravitreal triamcinolone injection for refractory macular edema. In one patient, a white material was found in the angle on gonioscopy. All three cases required surgical intervention to reduce the IOP. Conclusions Considering the early rapid rise in IOP in these three cases, we suggest that clinicians closely monitor patients after intravitreal triamcinolone injections for the development of acute glaucoma. Additionally, it may be advisable to perform gonioscopic examinations to look for any abnormal accumulation of material in the angle.

Intraocular pressure spike after YAG iridotomy in patients with pigment dispersion

Background: The role of laser peripheral iridotomy to break a suspected reverse pupil block in the long-term control of pigment dispersion is promising, but the usefulness of this procedure has not been completely established.The author examined whether patients with pigment dispersion are at higher risk for an intraocular pressure (I0P) spike after laser peripheral iridotomy due to possible compromise of trabecular meshwork function, compared with patients undergoing prophylactic peripheral iridotomy for an occludable angle.Methods: Data were collected prospectively on the first eye of 87 patients with occludable angles and 13 patients with pigment dispersion treated with peripheral laser iridotomy between November 1995 and October 1996 at the glaucoma service of a university-affiliated hospital in Toronto. All patients received one drop of 0.5% apraclonidine before the procedure. IOP was measured before and I and 24 hours after the procedure.Results: There was no difference between the two groups in the distribution of right vs. left eyes, sex, race, the mean total energy required to produce a patent iridotomy, the mean number of medications used or the mean IOP before the procedure.The patients with pigment dispersion were significantly younger than those with occludable angles (mean age [and standard deviation (SD)] 40.5 [9.45] years vs. 66.4 [10.78] years) (p < 0.001). There was no difference between the two groups in mean IOP at 1 hour or at 24 hours. Twenty-nine patients (33%) in the occludable angle group and seven (54%) in the pigment dispersion group had an IOP spike greater than 2 mm Hg after the procedure (p = 0.001). Among these patients, the mean IOP (36.4 [SD 10.83] mm Hg vs. 30.3 [SD 7.04] mm Hg, p = 0.05) and the mean rise in IOP (14.0 [SD 10.63] mm Hg vs. 8.7 [SD 4.73] mm Hg, p = 0.04) were significantly higher in those with pigment dispersion than in those with occludable angles. Among the patients who used antiglaucoma medications before the procedure or had a prelaser IOP level greater than 22 mm Hg, those with pigment dispersion were more likely than those with occludable angles to have an IOP spike at 1 hour (p ≤ 0.005).Interpretation: Patients with pigment dispersion undergoing iridotomy to break a reverse pupil block should be carefully assessed after the procedure, as significant pressure spikes requiring treatment may occur.

Letter To The Editor: Iop Effect Of Succinylcholine And Retrobulbar Block

Several investigators have showed that the rise in IOP after retrobulbar injection and succinylcholine injection is followed by decline in IOP. Comparing those research data show the similarity of the pattern of IOP changes after retrobulbar block and succinylcholine injection, which may support the argument that succinylcholine can be used in open globes.

Effects of daunomycin implants on filtering surgery outcomes in rabbits

Purpose. To evaluate the effects of a novel daunomycin (DM) implant on intraocular pressure (TOP), bleb survival, and anterior segment complications when administered during filtering surgery on New Zealand White rabbits.Methods. Implants were prepared by covalent coupling of DM to a high molecular weight hyaluronic acid (HA) and fabricated into solid implants containing 250, 65, and 25 μg of DM. Full thickness sclerostomies were performed, and rabbits received no implant (control), placebo implant containing HA, or an implant containing HA-DM conjugate at the time of surgery. Rabbits were then followed for 30 days to assess change in IOP, bleb survival, and anterior segment associated complications.Results. In vitro, the release of DM from the implants was a first order process with a half-life of 51 h. In control rabbits, rabbits receiving placebo implant, and rabbits receiving HA-DM (250 μg) implants, the mean IOPs on day 3 were 11.1 ± 1.6, 10.8 ± 2.7, and 14 ± 0.98 mm of Hg, respectively. On days 5 through 9, IOP in the control and placebo-implanted groups returned to preoperative levels. However, in rabbits receiving 250 μg of conjugated DM, mean IOP on day 7 was reduced from preoperative levels by 11.8 ± 3.2 mm of Hg (P<0.05). This reduction in IOP was significantly different (P<0.05) from both control and placebo implant groups, and IOPs remained at these levels until studies were terminated on day 30. In control and placebo-implanted rabbits, bleb size started decreasing on day 1, and by day 7, no blebs were observed. In rabbits receiving 250 μg HA-DM implants, mean bleb survival time was greater than 30 days. The DM-induced reduction in IOP and enhanced bleb survival was dose-dependent. In rabbits receiving 65 μg of conjugated DM, IOPs were significantly reduced through day 30; however, at times beyond day 19 there was a gradual rise in mean IOP as filtering procedures in individual animals began to fail. Mean bleb survival time was greater than 30 days for implants containing 65 μg of conjugated DM. In rabbits receiving HA-DM implant containing 25 μg of DM, IOPs were not significantly different from preoperative levels beyond day 9, and no significant enhancement in bleb survival was observed in these animals. Comparison of HA-DM conjugated implants to those containing equal doses of free DM demonstrated that the mean IOP change at 30 days were similar; however, there was a reduction in anterior segment complications associated with the use of HA-DM conjugated implants.Conclusions. This study provides evidence that the controlled release of DM when conjugated to HA can significantly improve the success of filtering procedures. The maintenance of ocular hypotension and bleb survival along with the reduction in anterior segment complications supports the idea that HA-DM conjugate will be more efficacious than the use of free DM in improving the success rate of filtering surgery. Curr. Eye Res. 17:844–850, 1998.

Effects of daunomycin implants on filtering surgery outcomes in rabbits

Purpose. To evaluate the effects of a novel daunomycin (DM) implant on intraocular pressure (TOP), bleb survival, and anterior segment complications when administered during filtering surgery on New Zealand White rabbits.Methods. Implants were prepared by covalent coupling of DM to a high molecular weight hyaluronic acid (HA) and fabricated into solid implants containing 250, 65, and 25 μg of DM. Full thickness sclerostomies were performed, and rabbits received no implant (control), placebo implant containing HA, or an implant containing HA-DM conjugate at the time of surgery. Rabbits were then followed for 30 days to assess change in IOP, bleb survival, and anterior segment associated complications.Results. In vitro, the release of DM from the implants was a first order process with a half-life of 51 h. In control rabbits, rabbits receiving placebo implant, and rabbits receiving HA-DM (250 μg) implants, the mean IOPs on day 3 were 11.1 ± 1.6, 10.8 ± 2.7, and 14 ± 0.98 mm of Hg, respectively. On days 5 through 9, IOP in the control and placebo-implanted groups returned to preoperative levels. However, in rabbits receiving 250 μg of conjugated DM, mean IOP on day 7 was reduced from preoperative levels by 11.8 ± 3.2 mm of Hg (P<0.05). This reduction in IOP was significantly different (P<0.05) from both control and placebo implant groups, and IOPs remained at these levels until studies were terminated on day 30. In control and placebo-implanted rabbits, bleb size started decreasing on day 1, and by day 7, no blebs were observed. In rabbits receiving 250 μg HA-DM implants, mean bleb survival time was greater than 30 days. The DM-induced reduction in IOP and enhanced bleb survival was dose-dependent. In rabbits receiving 65 μg of conjugated DM, IOPs were significantly reduced through day 30; however, at times beyond day 19 there was a gradual rise in mean IOP as filtering procedures in individual animals began to fail. Mean bleb survival time was greater than 30 days for implants containing 65 μg of conjugated DM. In rabbits receiving HA-DM implant containing 25 μg of DM, IOPs were not significantly different from preoperative levels beyond day 9, and no significant enhancement in bleb survival was observed in these animals. Comparison of HA-DM conjugated implants to those containing equal doses of free DM demonstrated that the mean IOP change at 30 days were similar; however, there was a reduction in anterior segment complications associated with the use of HA-DM conjugated implants.Conclusions. This study provides evidence that the controlled release of DM when conjugated to HA can significantly improve the success of filtering procedures. The maintenance of ocular hypotension and bleb survival along with the reduction in anterior segment complications supports the idea that HA-DM conjugate will be more efficacious than the use of free DM in improving the success rate of filtering surgery. Curr. Eye Res. 17:844–850, 1998.

The effect of an artificially elevated intraocular pressure on the central corneal curvature

Twenty-three Optometry students with normal corneal condition were recruited. The intraocular pressure and central corneal curvature of the right eye were measured in a sitting and a 30 ° head-down posture. The mean (standard deviation) IOPs before and during posture change were 15.6 (2.4) mmHg and 22.1 (2.3) mmHg respectively. This 6.5 mmHg mean rise in IOP was found to be statistically significant which is similar to the results from previous studies. The mean changes in radius of corneal curvature and the orientation of the axis of the vertical principal meridian were 0.02 mm (SD 0.025 mm) and 2.4 ° (SD 10.4 °) respectively. No significant variation was demonstrated on these keratometric results due to the 30 ° head-down posture. The maximum change in radius of curvature was only 0.055 mm for one subject. Perhaps this amount of pressure rise was not sufficient enough to distort the corneal surface centrally. Another possibility could be an even distribution of the elevated pressure around the cornea, or the distribution of pressure is not even but could not be revealed by a conventional keratometer.

The effect of an artificially elevated intraocular pressure on the central corneal curvature

SummaryTwenty‐three optometry students with normal corneal condition were recruited. The intraocular pressure and central corneal curvature of the right eye were measured in a sitting and a 30° head‐down posture. The mean (standard deviation) IOPs before and during posture change were 1 5.6 (2.4) mmHg and 22.1 (2.3) mmHg respectively. This 6.5 mmHg mean rise in IOP was found to be statistically significant which is similar to the results from previous studies. The mean changes in radius of corneal curvature and the orientation of the axis of the vertical principal meridian were 0,02 mm (SD 0.025 mm) and 2.4° (SD 10.4°) respectively. No significant variation was demonstrated on these keratometric results due to the 30° head‐down posture. The maximum change in radius of curvature was only 0.055 mm for one subject. Perhaps this amount of pressure rise was not sufficient enough to distort the corneal surface centrally. Another possibility could be an even distribution of the elevated pressure around the cornea, or the distribution of pressure is not even but could not be revealed by a conventional keratometer.

Apraclonidine Protection of the Blood-Aqueous Barrier from Traumatic Break-Down

This study investigated the effects of apraclonidine hydrochloride 1% eye drops on blood-aqueous barrier in 108 pigmented rabbits. The effects of pretreatment with dapiprazole and yohimbine, and a comparison with clonidine 0.125% eye drops are also reported. The disruption of blood-aqueous barrier was obtained by argon laser burning of the iris. The degree of permeability of the barrier was deduced by the amount of proteins in aqueous humor 60 min after laser application. Intraocular pressure and pupil diameter were also studied. Protein content in aqueous humor was 0.72 +/- 0.26 g/l in control rabbits that did not receive any treatment; 5.98 +/- 4.23 g/l in rabbits instilled with placebo eye drops and treated by laser burning of iris; 0.43 +/- 0.25 g/l in rabbits that received apraclonidine eye drops prior to laser burning; 2.19 +/- 1.3 g/l in rabbits that received apraclonidine eye drops immediately after laser application; 0.35 +/- 0.08 g/l in rabbits that received apraclonidine 1% eye drops both before and after laser application. Rabbits treated with clonidine 0.125% had a protein content in aqueous humor of 5.45 +/- 2.08 g/l after laser application. Dapiprazole 0.5% eye drops prior to apraclonidine led to a protein content in aqueous humor of 1.93 +/- 2.13 g/l; yohimbine 0.3% eye drops prior to apraclonidine led to a protein content of 0.70 +/- 0.40 g/l. Protein content in aqueous humor was 0.93 +/- 0.36 g/l, 0.82 +/- 0.899 g/l and 1.68 +/- 1.39 g/l in rabbits treated with yohimbine 0.3, 0.6 and 1.2 mg/kg i.v. and then with apraclonidine 1% eye drops. In one group of rabbits, the penetration into the aqueous humor of Evans blue injected intravenously was also studied. Evans blue content in aqueous humor was 0.03 +/- 0.08 mg/100 ml in control rabbits; 0.92 +/- 0.53 mg/100 ml in placebo rabbits treated by laser; and 0.28 +/- 0.19 mg/100 ml in apraclonidine rabbits treated by laser. Apraclonidine eye drops led to a decrease in IOP and prevented IOP rise following argon laser application. Placebo treated rabbits had a 20% increase in IOP following laser application. Apraclonidine-treated eyes showed mydriasis and blanching of the conjunctiva. These effects were not affected by pretreatment with dapiprazole or yohimbine. In these experiments, the treatment with apraclonidine 1% eye drops completely protected the blood aqueous barrier from the disruption caused by laser burning of the iris. The protection was less effective when apraclonidine was applied after laser burnings.

Development of cataract after trabeculectomy.

Cataract progression after trabeculectomy was investigated in a study of 47 eyes with exfoliative glaucoma (ExG) and in 20 eyes with primary open-angle glaucoma (POAG). Cataract progression was assessed from the need for cataract extraction, deterioration of visual acuity by > or = 2 Snellen lines, myopic change in the refraction and increase in the lens opacity value, measured with a Lens Opacity Meter 701. Measurements were made 6 and 12 months after trabeculectomy and at the follow-up visit at 26 +/- 11 months. ExG, age, hypotony (IOP < or = 5 mm Hg) lasting > or = 5 days and early postoperative IOP rise > 30 mm Hg were observed to be risk factors for cataract progression. In pairwise analysis of 14 patients, in which the unoperated eye served as the control, a myopic change of refraction was the most frequent indicator for a change in the structures of anterior segment, possibly indicating cataract progression.

The dexamethason provocative test: a predictive tool for glaucoma?

A retrospective follow-up study of 134 patients (84 women and 50 men) tested for their responsiveness to topically administered corticosteroids was carried out. Of the 134 patients tested, 34 (25.4%) had a high response (IOP rise greater than or equal to 16 mmHg), 66 (49.3%) an intermediate (IOP rise 6-15 mmHg) and 34 (25.4%) a low response (IOP rise less than or equal to 5 mmHg) to topically administered 0.1% dexamethasone eye drops. Follow-up time varied from 5 to 15 years (mean 7.1 years). During the follow-up period 29 (21.6%) patients developed glaucoma. Of these, 9 (31.0%) were high responders and 7 (24.0%) had a low response to corticosteroids. Log-linear analysis showed no correlation between corticosteroid response and development of glaucoma in the study eye (SD = 0.232, DF = 2, P = 0.890), the control eye (SD = 1.234, DF = 2, P = 0.540) or both eyes (SD = 0.618, DF = 2, P = 0.734). At the final examination 75 patients (56%) had an IOP of greater than or equal to 22 mmHg. Of these ocular hypertensive patients 28 (37.3%) were high responders, and 15 (20%) had a low response to corticosteroids. Of the whole material of 134 patients 44 had a family history of glaucoma. Eleven (25.1%) of these were high responders and 14 (31.8%) low responders. Of the 29 patients who developed glaucoma 8 had a family history of glaucoma. Of these 3 were high responders and 3 low responders. The results indicate that the dexaprovocative test yielded relatively limited value in the screening of patients for glaucoma.

Postoperative Intraocular Pressure Rise in Open-angle Glaucoma Patients after Cataract or Combined Cataract-filtration Surgery

Postoperative intraocular pressure (10P) was measured in patients with open-angle glaucoma undergoing extracapsular cataract extraction with a posterior chamber lens implant (ECCE-PC IOL). Patients considered to be under adequate medical glaucoma control had cataract surgery alone or combined with a posterior lip sclerectomy. Patients with medically uncontrolled glaucoma had cataract surgery combined with either a posterior lip sclerectomy or a trabeculectomy. Cataract surgery alone (n = 26) was associated with a significantly (P < 0.001) increased IOP on postoperative day 1: preoperative IOP, 18.9 ± 3.6 mmHg; postoperative IOP, 34.2 ± 12 mmHg. An IOP rise of 10 mmHg or more occurred in 69% of the eyes, whereas 77% of the eyes had an absolute IOP over 25 mmHg. Eyes undergoing combined surgery (n = 42) had a preoperative IOP of 21.3 ± 4.8 mmHg. On postoperative day 1, the mean IOP was 14.9 ± 12.0 mmHg. An IOP rise of 10 mmHg or more was observed in 14%, and an IOP over 25 mmHg in 21 % of combined surgery eyes. Cataract surgery in eyes with open-angle glaucoma requires careful monitoring and therapy for early postoperative increases in IOP. Combined surgery reduces the frequency and magnitude of, but does not eliminate, this complication.

Intraocular pressure effects of water loading and venous compression tests in normal and denervated pigmented rabbits

We have compared IOP elevations induced by water-loading and by increased cephalic venous pressure in normal and denervated pigmented rabbits. Denervations were performed by sympathetic ganglionectomy and/or blockade of the sensory and autonomic innervation of the eye through retrobulbar anesthesia; retrobulbar anesthesia induced significant decreases of the basal IOP in control but not in ganglionectomized eyes. The water-loading test induced a peak pressure elevation approximately 30 min after water administration that could be counteracted by retrobulbar anesthesia. Ganglionectomized rabbits exhibited steeper IOP rises and greater IOP increases following water-loading than the control eyes; retrobulbar anesthesia in ganglionectomized eyes delayed the IOP response to water-loading. Compressions of the neck lasting 30 min elicited significant IOP elevations that were more pronounced in ganglionectomized eyes. In these eyes, retrobulbar anesthesia further increased the IOP rise elicited by neck compression. An IOP decrease below control values was observed at the end of the venous compression. The results indicate that an intact efferent innervation of the eye contributes to buffer IOP elevations induced by water-loading or cephalic venous stasis, presumably through the vascular effects of the ocular autonomic nerves.

2 new possibilities for using balloon occlusion in relation to the indentation effect

Two new applications of the balloon are described which exploit its variable indentation: in the first case, the volume is reduced by withdrawal of fluid; in the second it is increased by additional injection. In both cases the procedure consists in two steps performed in subconjunctival anesthesia. In the first case the balloon provides intraocular space prior to gas injection (giant tear detachment). In the first step the balloon is inserted into the parabulbar space. After one to two hours this results in a deep indentation of the globe. In the second step the balloon indentation is used to compensate for the rise in IOP induced by the gas injection. With this "balloongasprocedure", a kind of fluid-gas-exchange is performed by injecting 1.0 ml of an expanding perfluorocarbon gas without prior drainage or pars plana vitrectomy. In the second case, the balloon is used in cases of detachment to interrupt retinal circulation prior to occlusion of a recurrently hemorrhaging vessel using the laser. In the first step, the tear is tamponaded by the parabulbar balloon and with this, the artery crossing the horseshoe tear is attached as well. In the second step, by increasing the balloon volume, retinal circulation is interrupted prior to occlusion of the artery by laser with reduced risk of hemorrhage. In both applications of the balloon a relatively complex detachment operation is divided into two smaller principle of less risky procedures on the surgery in small steps.

ARGON LASER TRABECULOPLASTY FIVE YEARS ON

The results of argon laser trabeculoplasty (ALT) in a series of 252 patients are presented with follow-up of up to five years. The procedure is effective in chronic open-angle glaucoma (COAG), ocular hypertension and pseudoexfoliative (PXF) glaucoma. Most cases were treated initially over 180 degrees of the angle and repeat treatment of the remaining 180 degrees usually resulted in an additional fall in IOP which was maintained at two, three and four year follow-up with only a small number of these retreated cases having no fall on later follow-up. ALT was not very effective in further lowering IOP in eyes with IOP controlled to a low level before treatment or in low tension glaucoma. It was effective in most of a number of miscellaneous glaucomas including pigmentary glaucoma. Apart from the immediate high rise in IOP the main complication was a late high rise in IOP which was serious in degree and appeared mainly in PXF but also in two cases of ocular hypertension. The presence of a concomitant fall in IOP in the fellow untreated eye is important and probably due to better compliance with treatment. Almost all cases required medical treatment for glaucoma which could not be ceased after ALT. ALT should be seen as an adjunct to, but not a substitute for, medical treatment.

Anesthesia for Ophthalmic Surgery in the Elderly

The effects of clonidine on intraocular pressure and perioperative cardiovascular variables were studied by a randomized double blind design in 80 elderly patients (ASA physical status I-III) scheduled for elective ophthalmic surgery under general anesthesia (GA) and local anesthesia (LA). Group 1 (n = 40), the control group, received diazepam po (0.1 mg.kg-1) 90-120 min prior to arrival to the operating room. Group 2 (n = 40) received clonidine po approximately 5 micrograms.kg-1 po at the same time. Each group was divided into subgroups of 20 patients each to be managed with GA (GA subset) or LA (LA subset). Ninety to 120 minutes after the premedication, a large decrease in IOP from 20 +/- 3 to 12 +/- 3 mmHg (P less than 0.01) and a small but significant reduction of both systolic and diastolic BP and HR were observed in patients receiving clonidine, while no changes occurred in controls. In the patients managed with GA, clonidine effectively prevented IOP rise and attenuated the associated cardiovascular response (P less than 0.01) following laryngoscopy and tracheal intubation, and significantly reduced intraoperative cardiovascular lability and anesthetic requirement for isoflurane (P less than 0.05) and for fentanyl (P less than .001). In patients managed with LA, intraoperative systolic (P less than 0.01) and diastolic BP and HR variability (P less than 0.05) were significantly lower in patients receiving clonidine as compared to controls. Intraoperatively, a significantly higher incidence of hypertension (P less than 0.01) and tachycardia (P less than 0.05) were respectively observed in the LA subset and GA subset of the controls when contrasted with the corresponding subset of those receiving clonidine. Moreover, clonidine was more effective than diazepam as a premedication; in fact, satisfactory intraoperative sedation and cardiovascular stability were observed in 85% of the patients who received clonidine, and in 50% of those patients who did not receive clonidine (P less than 0.01). Thus, clonidine may represent a useful adjunct in the management of the aged patient in the setting of ophthalmic surgery.