Efficacy of Selective Laser Trabeculoplasty in Patients on Systemic Immunosuppressive Therapy

PRCIS

When comparing patients on systemic immunosuppressive therapy to those without, there was no difference in intraocular pressure (IOP) early after SLT; however, at 1 year following SLT, IOP was higher in the immunosuppression group compared with controls.

PURPOSE

To determine whether patients taking systemic immunosuppressive medications have a different IOP-lowering response to selective laser trabeculoplasty (SLT) compared with a control group of patients.

METHODS

All patients who underwent SLT at Mayo Clinic 2017-2021 were identified. Patients on systemic immunosuppressive medications at the time of SLT were compared with control patients not receiving systemic immunosuppressive medications. The primary endpoints of this study were the percentage IOP reduction at 1 to 2, 3 to 6, and 12 months. Additional analyses included the percentage of patients who did not require additional therapy at each time point.

RESULTS

There were 108 eyes of 72 patients that underwent SLT in the immunosuppressed group and 1997 eyes of 1417 patients in the control group. There was no significant difference in age-adjusted change in IOP between groups at the first postoperative visit 1 to 2 months following SLT (-18.8±20.7% vs. -16.0±16.5%, P =0.256) or 3-6 months following SLT (-15.2±21.6% vs. -18.3±23.2%, P =0.062). However, at 12 months following SLT, the IOP reduction in the immunosuppressive therapy group was significantly less compared with the control group (-15.1±21.2% vs. -20.3±22.9%, P =0.045). There was no difference between groups in the number of additional treatments during the study intervals.

CONCLUSION

Patients in the systemic immunosuppressive therapy group showed equivalent early IOP-lowering after SLT compared with a control group, but the treatment response was diminished at 1 year. Further studies investigating IOP regulation after SLT in immunosuppressed patients are needed.

Dexamethasone Intravitreal Implant Injection in Eyes with Comorbid Hypotony

PURPOSE

To evaluate outcomes in patients with hypotony treated with intravitreal dexamethasone implant (Ozurdex).

DESIGN

Retrospective cohort study.

PARTICIPANTS

Thirteen patients (15 eyes) that received a total of 99 dexamethasone implant injections on occasions at which the intraocular pressure was low, meeting the definition of statistical hypotony.

METHODS

The medical records of 13 patients (15 consecutive eyes) receiving 1 or more intravitreal dexamethasone implants between December 2014 and April 2017 were reviewed retrospectively. Hypotony was defined as intraocular pressure less than 6.5 mmHg. The indications for intravitreal dexamethasone implant injection were intermediate or posterior uveitis (86.7%), diabetic macular edema (13.3%), and/or cystoid macular edema (6.7%).

MAIN OUTCOME MEASURES

The primary outcome measures were safety outcomes and best visual acuity within 6 months of the final intravitreal dexamethasone implant injection in a hypotonous eye.

RESULTS

In 15 eyes (13 patients), 99 injections were administered to eyes under circumstances of hypotony. Uveitic cystoid macular edema or diabetic macular edema was reduced after treatment in all cases. No complications were noted during the injection procedure. Three complications were noted in 2 patients after injection. Pseudophakodonesis and mild vitreous hemorrhage immediately after injection were noted in 1 patient, and a case of delayed-onset vitreous hemorrhage with pigment release was noted in another. All 3 complications resolved without intervention. The primary end point of this study-mean visual acuity-was stable over the follow-up period. In patients with hypotony whose intraocular pressure normalized during the follow-up period, this was attributable to management of glaucoma surgery-related complications rather than an effect of the intravitreal dexamethasone implant.

CONCLUSIONS

Intravitreal dexamethasone implant injection is a reasonable treatment option for patients with comorbid hypotony in whom clinical findings warrant treatment with a sustained-delivery intravitreal steroid implant. Further studies, including imaging of zonules before and after intravitreal dexamethasone implant injection in a hypotonous eye, could help define risks to intraocular lens stability with this procedure.

Novel surgical management of cyclodialysis cleft via anterior chamber perfusion: Case report

RATIONALE

Cyclodialysis cleft is a relatively rare but severe condition with persistent ocular hypotony, which can cause morphologic changes and visual loss. Here we report a case of a traumatic cyclodialysis cleft that was successfully managed with direct cyclopexy via anterior chamber perfusion. During the operation, if there is aqueous humor flowing out of the deep scleral incision, the cleft is not closed, and surgery should continue until there is no aqueous outflow.

PATIENT CONCERNS

A 66-year-old man was treated for severe blunt ocular trauma of the left eye and a resultant cyclodialysis cleft, lens subluxation, choroidal detachment and a cataract. His intraocular pressure was 6 mm Hg, he presented with a shallow anterior chamber, phacodonesis, iridodonesis, 360° ciliary body detachment, and a suspicious cyclodialysis cleft in the 5 to 8 o'clock position. DIAGNOSES:: ocular blunt trauma (left eye), cyclodialysis cleft (left eye), lens subluxation (left eye), choroidal detachment (left eye), cataract (both eyes).

INTERVENTIONS

The cataract was extracted by phacoemulsification and a posterior chamber intraocular lens was implanted with 2 capsular tension rings, one in the lens bag and the other in the ciliary sulcus. Throughout the following month, intraocular pressure fluctuated between 4 and 6 mm Hg and the ciliary body failed to reattach. A cyclopexy via anterior chamber perfusion was thus deemed necessary and performed.

OUTCOMES

After cyclopexy, intraocular pressure increased to 27 mm Hg and decreased to 16 mm Hg after brinzolamide eye drops treatment twice daily for 4 days. Subsequently intraocular pressure stabilized between 10 to 21mm Hg. Complete closure of the cyclodialysis cleft was confirmed with ultrasound biomicroscopy.

LESSONS

Cyclopexy via anterior chamber perfusion for patients with cyclodialysis cleft is a simple, safe, and efficient technique that ensures a successful surgery.

[Comparison of intraocular pressure lowering efficacy of bimatoprost / timolol fixed combination and other glaucoma medications in the treatment of glaucoma]

AIM

To compare intraocular pressure (IOP) lowering efficacy of bimatoprost 0.03% / timolol 0.5% fixed combination (BTFC) and other combinations of glaucoma drugs (bimatoprost, latanoprost 0.005% / timolol 0.5% fixed combination, separate use of travoprost 0.004 % and timolol 0.5 %) in patients with glaucoma.

PATIENTS AND METHODS

Fifty-three patients with glaucoma were divided into 3 groups according to their original glaucoma therapy. BTFC was used by the patients for a period of 3 months. After 1 week, 1, 2 and 3 months, the diurnal IOP curves were performed. Side effects of the new treatment were recorded and compared to the original therapy.

RESULTS

The mean diurnal IOP reduction in the group of patients switching from bimatoprost to BTFK reached 4.4 +/- 2.28 mm Hg (p < 0.01). In the group of patients initially on latanoprost / timolol fixed combination, the IOP decreased with BTFK by 2.3 +/- 1.5 mm Hg (p < 0.01). Changing therapy from travoprost / timolol seperate combination to BTFK caused an IOP decrease by 2.3 +/- 1.5 mm Hg on average (p < 0.01). Conjunctival hyperemia with initial therapy was experienced in 33% of patients in our study group. With BTFK application, the hyperemia improved in 69% of these patients, got worse in 12.5% and remained unchanged in 19% of the patients. Patients found the BTFK better than the original medication in 37.5% of cases, the same in 52% and worse in 10.5%. Five patients terminated the study earlier due to poor IOP compensation or marked side effects of BTFK.

CONCLUSION

In all three groups of glaucoma patients there was a significant and prolonged decrease in IOP after treatment with BTFK. The use of BTFK was accompanied by smaller incidence of conjunctival hyperemia compared to isolated bimatoprost or travoprost / timolol combination.

Stereoselectivity of satropane, a novel tropane analog, on iris muscarinic receptor activation and intraocular hypotension

AIM

To study the stereoselectivity of satropane (3-paramethylbenzene sulfonyloxy-6-acetoxy tropane), a novel tropane analog, on iris muscarinic receptor activation and intraocular hypotension.

METHODS

The assays for radioligand-receptor binding, the contractile responses of isolated iris muscle, the miosis response, and the intraocular hypotension of the enantiomers of satropane were investigated.

RESULTS

In the binding analysis, S(-)satropane (lesatropane) completely competed against the [3H]quinuclydinyl benzilate-labeled ligand at muscarinic receptors in the iris muscle, whereas R(+)satropane failed to completely compete. In an isolated iris contractile assay, R,S(+/-)satropane and S(-)satropane produced a concentration-dependent contractile response with similar efficacy and potency to that of carbachol. R(+)satropane did not induce any contractile response. In the pupil diameter measurement assay in vivo, S(-)satropane induced miosis much more effectively than pilocarpine, while R(+)satropane failed to produce any miosis. In the water loading-induced and methylcellulose-induced ocular hypertensive models, S(-)satropane, but not R(+)satropane, significantly suppressed intraocular pressure at a much lower concentration than pilocarpine.

CONCLUSION

The agonistic and hypotensive properties of satropane on rabbit eyes are stereoselective, with the S(-)isomer being its active form.

AL-34662: A Potent, Selective, And Efficacious Ocular Hypotensive Serotonin-2 Receptor Agonist

PURPOSE AND METHODS

The aim of this study was to determine the ocular pharmacological characteristics of AL-34662 (1-((S)-2-aminopropyl)-1H-indazole-6-ol), a new synthetic serotonin-2 (5-HT2) receptor-agonist ocular hypotensive agent. A variety of well-documented in vitro and in vivo procedures were utilized to study the pharmacological attributes of AL-34662.

RESULTS

AL-34662 exhibited a high affinity for the rat and human 5-HT2 receptor (IC50=0.8-1.5 nM) and for cloned human 5-HT2A-C receptors (IC50=3-14.5 nM). AL-34662 stimulated phosphoinositide turnover in human ciliary muscle (h-CM; EC50=289+/-80 nM) and in human trabecular meshwork (h-TM; EC50=254+/-50 nM) cells. AL-34662 also mobilized intracellular Ca2+ ([Ca2+]i) in h-CM (EC50=140+/-23 nM) and h-TM (EC50=38+/-8 nM) cells, being a full agonist like 5-HT itself. AL-34662's effects in the h-CM (and h-TM) cells were potently antagonized by 5-HT2A-antagonist M-100907 (IC50=1.8+/-0.7 nM), but weakly by 5-HT2B-antagonist (RS-127445 IC50>10 microM), 5-HT2B/C- antagonist (SB-242084 IC50=2.08 microM) and 5-HT2C antagonist (RS-102221 IC50>1 microM). AL-34662 caused relatively minimal ocular discomfort and hyperemia in rabbit and guinea pig eyes. It efficaciously lowered intraocular pressure (IOP) in the conscious ocular hypertensive monkey eyes (33% at 300 microg). The (R)-enantiomer (AL-34707) and the racemate (AL-34497) were less potent and/or efficacious than AL-34662 in all of these assays.

CONCLUSIONS

AL-34662 is a high-affinity 5-HT2 receptor agonist that potently mobilizes [Ca2+]i in h-CM and h-TM cells, and which efficaciously lowers IOP in conscious ocular hypertensive cynomolgus monkey eyes through a local effect with minimal side-effects.

The use of intravitreal gas for the treatment of ocular hypotony after glaucoma filtration surgery

Hypotonous maculopathy is a serious complication of glaucoma filtration surgery. A patient with hypotonous maculopathy due to excessive filtration was treated with intravitreal gas. During the next several months, the intraocular pressure increased and the visual acuity improved. Intravitreal gas is useful for the treatment of hypotonous maculopathy due to excessive aqueous filtration.

Effects of novel ethacrynic acid derivatives on human trabecular meshwork cell shape, actin cytoskeletal organization, and transcellular fluid flow

To determine efficacy and therapeutic index in the context of ocular hypotensive activity of the new ethacrynic acid (ECA) derivatives of the series (SA8,248 and SA8,389), 9,000 series (SA9,000, SA9,622 and SA9,995) and ticrynafen, we undertook a comparative evaluation of the dose-dependent effects of these compounds on human trabecular meshwork (HTM) cell shape, actin cytoskeletal organization, focal adhesions and transcellular fluid flow. Responses were either scored using an arbitrary scale of 1-5 or quantified. Compounds of the 9000 series (SA9,995>SA9,000>SA9,622) were found to be 14- to 20-fold more potent than ECA, ticrynafen or analogs from the 8,000 series (SA8,389>SA8,248) in terms of ability to induce cell shape alterations in HTM cells. Similarly, compounds of the 9,000 series (SA9,995>SA9,622>SA9,000) were found to be much stronger (2 to 20 fold) than ECA, ticrynafen or analogs of the 8000 series in terms of affecting decreases in actin stress fiber content in HTM cells. Analogs of the 9000 series (SA9,622>SA9,995>SA9,000) were also observed to be 8 to 10 fold more potent than ECA (SA8,389>ECA>SA8,248>ticrynafen) at eliciting decreases in cellular focal adhesions. Interestingly, analogs of the 9000 series (SA9,000>SA9,622>SA9,995) and SA8,248 demonstrated a huge increase (by many folds) in transcellular fluid flow of HTM cell monolayers as compared to ECA and ticrynafen. Collectively, these analyses revealed that the structural modification of ECA improves its ocular hypotensive efficacy, indicating that the SA9,000 series compounds might be promising novel ocular hypotensive drugs.

Intracameral 2.3% sodium hyaluronate to treat postoperative hypotony in patients with glaucoma

BACKGROUND AND OBJECTIVE

To evaluate the intracameral use of Healon5 (2.3% sodium hyaluronate) (Advanced Medical Optics, Santa Ana, CA) in patients with hypotony.

PATIENTS AND METHODS

Fifteen consecutive patients with glaucoma who had hypotony for at least 7 days were prospectively recruited. Indications for the intracameral injection of Healon5 were an intraocular pressure (IOP) of less than 6 mm Hg with negative results on Seidel test.

RESULTS

The mean IOP readings at baseline, 1 to 2 weeks post-injection, and 4 to 6 weeks post-injection were 3.8 +/- 1.58, 6.58 +/- 2.62, and 6.50 +/- 2.24 mm Hg, respectively. The increase in IOP at both follow-up points was significant (P < .01). The visual acuity improvement was small but significant at the 4 to 6 week point (P = .05). In the early-onset cases, IOP increased significantly from baseline at both follow-up points (P< .05), but visual acuity did not. No significant change from baseline IOP or visual acuity occurred among the late-onset cases. The existing hypotony-related conditions consistently improved by the 4 to 6 week point.

CONCLUSIONS

Intracameral injection of Healon5 raised IOP more in early-onset hypotony cases than in late-onset cases. Although the improvements in IOP and visual acuity were statistically significant, the overall clinical picture did not change because the endpoint IOP was still hypotonus. Twenty percent of the patients had IOP spikes that required medical treatment.

Topical ibopamine in the treatment of chronic ocular hypotony attributable to vitreoretinal surgery, uveitis, or penetrating trauma

PURPOSE

To study whether topical ibopamine effectively increases the intraocular pressure in patients with ocular hypotony after vitreoretinal surgery, uveitis, or penetrating trauma.

DESIGN

A prospective randomized, double-blind, placebo controlled, crossover study.

METHODS

In ten patients with ocular hypotony, an ibopamine 2% solution or placebo eyedrop was administered at 8 am and frequent applanation tonometry was performed during 10 hours on 2 days, 2 weeks apart.

RESULTS

The mean IOP integral after administration of ibopamine was 2.4 mm Hg higher (95% CI for median difference in AUC over 480 minutes [P = .010]) compared with placebo.

CONCLUSIONS

The results of the study show that an ibopamine 2% eyedrop twice a day may increase the IOP for a period of over 8 hours in patients with hypotony.

Management of severe hypotony with intravitreal injection of viscoelastic

PURPOSE

To investigate the effect of an intravitreal injection of sodium hyaluronate 1.4% and 2.3% in the treatment of hypotony.

DESIGN

Interventional case series.

METHODS

Intravitreal injection of sodium hyaluronate 1.4% was performed to treat persistent hypotony in three eyes after the successful repair of retinal detachment and in one eye with uveitis. Injection of sodium hyaluronate 2.3% was performed in one eye after the successful repair of retinal detachment with removal of silicone oil.

RESULTS

At the last follow-up examination (2-16 months), intraocular pressure increased to at least 5 mm Hg (5-14 mm Hg) in all eyes that had been injected with sodium hyaluronate. Intraocular pressure increased to 38 mm Hg in the eye that had been injected with sodium hyaluronate 2.3% on postoperative day 1 and was 10 mm Hg at three months. Vision improved in all patients.

CONCLUSION

Intraocular injection of sodium hyaluronate 1.4 and 2.3% appears to be efficacious in reversing hypotony in some eyes. Functional and structural findings can also improve.

AL-12182, a novel 11-oxa prostaglandin analog with topical ocular hypotensive activity in the monkey

A series of 11-oxa prostaglandin analogs was evaluated for FP receptor binding and activation. Several compounds having aryloxy-terminated lower chains were found to be potent agonists. Topical ocular dosing of AL-12182, the isopropyl ester prodrug of the potent agonist 13, lowered intraocular pressure in the monkey by 40% accompanied by minimal conjunctival hyperemia in the rabbit. AL-12182 was synthesized on multigram scale starting with D-sorbitol.

15-Fluoro prostaglandin FP agonists: a new class of topical ocular hypotensives

A novel series of 15-fluoro prostaglandins with phenoxy termination of the omega-chain was synthesized and evaluated for binding and functional activation of the prostaglandin FP receptor in vitro and for side effect potential and topical ocular hypotensive efficacy in vivo. Compounds with the 15alpha-fluoride relative stereochemistry displayed EC50 values of <or=20 nM, comparable to the value for the endogenous ligand PGF2alpha. Evaluation of selected ester prodrugs of these 15-fluoro prostaglandins in vivo highlighted their generally low propensity to elicit hyperemia or ocular irritation in rabbits and efficacious intraocular pressure-lowering property in monkeys. In particular 13,14-dihydro-15-deoxy-15alpha-fluoro-16-aryloxy-omega-tetranor-cis-Delta4-PGF2alpha isopropyl ester (24) caused relatively little ocular irritation in rabbits while lowering intraocular pressure in conscious ocular hypertensive monkeys by 39% following a topical ocular dose of 3 microg.

Stabilization of post-trabeculectomy flat anterior chamber with Healon and sulfur hexafluoride

We present the management of 2 cases of post-trabeculectomy flat anterior chamber with hypotony due to an overflowing fistula. When separate attempts to reform the anterior chamber by intracameral injection of sulfur hexafluoride (SF(6)) and sodium hyaluronate 1.0% (Healon) failed, we injected SF(6) 100% with Healon into the anterior chamber. This stabilized the anterior chamber without compromising the integrity of the filtering bleb. No complications were observed. This simple, safe, and effective procedure offers another option for the management of a flat anterior chamber due to overfiltration.

Ocular hypotensive effects of cholinergic and adrenergic drugs may be influenced by prostaglandins E2 in the human and rabbit eye

PURPOSE

Increased PGE2 production by the iris and ciliary body regulate intraocular pressure (IOP) in vivo. Various cholinergic and adrenergic compounds are traditionally used as antiglaucoma drugs, and their effect on IOP reduction is antagonised by cyclooxygenase inhibitors, indicating a role for eicosanoids in their hypotensive activity. One of the most potent antiglaucoma drugs, PG2 alpha (Latanoprost), reduces IOP by increasing uveoscleral outflow and also increases PGE2 production by the iris and ciliary body in vivo. We investigated whether cholinergic and adrenergic antiglaucoma drugs induce the production of prostaglandin E2 (PGE2) in vitro by: 1) the iris-ciliary body (ICB) of rabbits and, 2) irises of glaucoma patients.

METHODS

Pilocarpine 2%, epinephrine 1% and echothiophate iodide 0.125% were applied topically to both eyes of Albino rabbits. Control groups were treated with the corresponding vehicles, or untreated completely. Human iris specimens were obtained from nine untreated cataract eyes, and five eyes under antiglaucoma medication undergoing surgery. PGE2 were determined by a radioimmunoassay.

RESULTS

PGE2 production by the ICB of treated rabbits in vitro was twice that of vehicle-treated or untreated rabbit eyes (p<0.001, for either group). In vitro PGE2 production by treated glaucoma patients' irises was three times higher (p<0.001) than in cataract control patients.

CONCLUSIONS

The study found an increase in in vitro production of PGE2 by the irises of eyes treated with cholinergic and adrenergic antiglaucoma medications. This suggests a role for endogenous PG production in the hypotensive effect of both classes of drug.

Travoprost: a potent ocular hypotensive agent

Travoprost (isopropyl (Z)-7-[(1R,2R,3R,5S)-3,5-dihydroxy-2-[(1E,3R)-3-hydroxy-4-[alpha,alpha,alpha,trifluoro-m-tolyl)oxy]-1butenyl]cyclopentyl]-5-heptenoate) is an isopropyl ester prodrug and a high-affinity, selective FP prostaglandin- receptor full agonist. This prodrug is a synthetic prostaglandin analogue, which in appropriate cases is administered topically for the treatment of glaucoma and ocular hypertension. The isopropyl ester prodrug is rapidly hydrolyzed by esterases in the cornea to the biologically active, free acid. Travoprost has demonstrated preferential affinity and full agonist activity for the FP receptor in the nanomolar range, with no meaningful affinity or activity at other receptors. Like other compounds of this class, the reduction of intraocular pressure by travoprost is due at least in part to increased uveoscleral outflow. Results from phase II and phase III pivotal studies for FDA approval in the United States have demonstrated that travoprost is an effective topical agent for treatment of elevated intraocular pressure in patients with open-angle glaucoma and ocular hypertension. Travoprost is a safe drug, with local side effects including hyperemia, eyelash growth and iris color change. The dosing is once per day in the evening, and storage does not require refrigeration. Travoprost will be a helpful new drug in the medical management of glaucoma.

Ocular hypotensive action of topical flunarizine in the rabbit: role of sigma 1 recognition sites

In a previous study we ascertained the presence of sigma1 and sigma2 recognition sites in the rabbit iris-ciliary body, an ocular structure involved in aqueous humor production and drainage. We characterized the sigma1 sites using the preferential ligand (+)-pentazocine, which caused a significant reduction of intraocular pressure (IOP). In the present study, flunarizine, a calcium channel blocker with a complex pharmacological profile, bound to sigma1 sites expressed in the iris-ciliary body with moderate affinity (K(i) = 68 nM). Unilateral topical flunarizine (0.01-0.1%) caused a dose-related reduction of IOP in ocular normotensive rabbits and in the alpha-chymotrypsin model of ocular hypertension, without altering the IOP of the contralateral eye. This activity was blocked by the sigma1 site antagonist NE-100 [N,N-dipropyl-2-[4-methoxy-3-(2-phenylethoxy)phenyl]ethylamine HCl] which, by itself, had no effect on IOP. Detection of flunarizine in rabbit iris-ciliary body homogenates, after topical instillation, showed that it adequately penetrates the rabbit eye. To investigate mechanisms that may contribute to ocular hypotension induced by sigma1 agonists, we carried out in vitro studies on the isolated rabbit iris-ciliary body. Flunarizine (IC50 = 5. 96 nM) and (+)-pentazocine (IC50 = 3. 81 nM) inhibited [3H]norepinephrine release. Moreover, flunarizine (IC50 = 6.34 nM) and (+)-pentazocine (IC50 = 27.26 nM) also antagonized isoproterenol-induced cAMP accumulation. The action of flunarizine and (+)-pentazocine was sensitive to NE-100 antagonism; however, this latter compound partially prevented their effect on [3H]norepinephrine and cAMP accumulation. These findings indicate that flunarizine and (+)-pentazocine interact with ocular sigma1 sites and may prove effective in the control of ocular hypertension.

The use of autologous fibrinogen concentrate in treating ocular hypotony after glaucoma filtration surgery

Antimetabolite therapy with 5-fluouracil (5-FU) or mitomycin-C (MMC) has significantly improved the success rate of glaucoma filtration surgery. However, in some eyes, when filtration is excessive, persistent hypotony may develop. In this study, we describe the experience of using autologous fibrinogen concentrate (AFC) to treat patients with persistent hypotony after glaucoma filtration surgery. Among seven MMC-augmented trabeculectomy patients who developed persistent postoperative hypotony, the effects of AFC intrableb injections were evaluated. Under a microscope, 0.2 ml AFC and bovine thrombin were injected into the blebs of the patients from both sides of the filtering blebs. Postoperative best-corrected visual acuity, anterior chamber status, intraocular pressure (IOP) and fundus examination were followed and compared with those preoperative. On the second day, the mean IOP of seven eyes elevated from preoperative 3.4 +/- 2.1 mmHg to 12.6 +/- 4.2 mmHg, and the anterior chamber became deep without obvious inflammatory response. Within two weeks, macular edema and visual acuity were noted to improve in six eyes (85.7%). In addition, after a mean follow-up of 25 months, the trabeculectomy procedure remained successful in all eyes. AFC appears to be safe and effective in the treatment of ocular hypotony after glaucoma filtration surgery.

Treatment of severe ocular hypotony in AIDS patients with cytomegalovirus retinitis and cidofovir-associated uveitis

OBJECTIVE

To describe the medical treatment of severe ocular hypotony in HIV-seropositive patients with cytomegalovirus retinitis and cidofovir-associated uveitis.

PATIENTS AND METHODS

Two HIV-seropositive patients with cytomegalovirus retinitis and cidofovir-associated uveitis complicated by severe ocular hypotony were unresponsive to conventional therapy after treatment with cidofovir was stopped. They were subsequently treated successfully with ibopamine 2% eyedrops and dexamethasone 0.1% eyedrops.

RESULTS

In both cases, an increase in intraocular pressure to normal values was observed on average 18.5 days after starting treatment. Intraocular pressure remained stable while on therapy for a mean follow-up of 9.5 months. During the follow-up period, any attempt to stop treatment was followed by an intraocular pressure decrease; conversely, restoration of therapy increased intraocular pressure to normal values. No reactivation of cidofovir-associated uveitis or cytomegalovirus retinitis was observed during the follow-up period.

CONCLUSIONS

Ibopamine 2% eyedrops in combination with dexamethasone 0.1% eyedrops is a satisfactory therapy for severe ocular hypotony in patients with cytomegalovirus retinitis and cidofovir-associated uveitis.

A simple treatment for chronic postoperative hypotony of unknown etiology: the injection of balanced salt solution into the anterior chamber

Postoperative hypotony is not rare. When it occurs, effective treatment must be initiated to avoid secondary complications. We report two cases of postoperative hypotony that have been treated successfully with a single injection of balanced salt solution (BSS) into the anterior chamber. One patient developed hypotony three months after combined cataract surgery and trabeculectomy with the use of Mitomycin C (MMC). The cause of hypotony remained unknown. Leakage, hyperfiltration, cyclodialysis, and other possible causes had been excluded. With a single injection of BSS into the anterior chamber the long-standing hypotony was successfully managed. A second patient with hypotony after pars plana vitrectomy was also treated successfully with an injection of BSS into the anterior chamber. We conclude that an injection of BSS into the anterior chamber is an inexpensive and efficacious remedy for postoperative hypotony of unknown etiology.

Ibopamine treatment in chronic hypotony secondary to long-lasting uveitis. A case report

PURPOSE

To assess the clinical efficacy of ibopamine eye drops in severe hypotony secondary to chronic progressive uveitis.

METHODS

Case report. A 47-year-old man with a 37-year history of diffuse uveitis and severe refractory hypotony was treated with topical 2% ibopamine (Trazyl) six times a day. Intraocular pressure, visual acuity, visual field and side effects were recorded during 15 months of follow-up.

RESULTS

IOP, visual acuity and visual field increased after four days of therapy and lasted for two months when the drug was suspended because of the onset of filamentous keratopathy. A new course of treatment with 2% ibopamine eye drops in a different solvent (BSS) resulted in a stable increase in IOP, VA and visual field, with no side effects in a follow-up of 13 months.

CONCLUSIONS

Ibopamine 2% eye drops in BSS solvent seem effective in the treatment of uveitis-related hypotony.

[An experimental study on effect of methazolamide on decreasing intraocular pressure in rabbits]

OBJECTIVE

To study the therapeutic effect of methazolamide on glaucoma.

METHODS

Various doses of methazolamide were orally administered in rabbits, their effects on high intraocular pressures and on recovery of low intraocular pressures were observed.

RESULTS

The high intraocular pressures were significantly decreased and the maintenance of low intraocular pressure was significantly prolonged by the oral administration of 40, 20, 10 mg/kg of methazolamide. A dose-effect relationship that is the reduction of intraocular pressure increases with the increase of the dosage administration of methazolamide could be observed.

CONCLUSION

This study indicates that methazolamide might play an effective therapeutic role in glaucoma.

Myopia, hypotony, and lenticular shift following strabismus surgery

A 5-year-old girl had hypotony, myopia, and anterior displacement of the lens-iris diaphragm following routine strabismus surgery. This constellation of findings suggests that surgical manipulation of the intact sclera produced a limited effusion involving the supraciliary space. Following cycloplegia, these findings resolved over several weeks, suggesting that this rare complications is self-limited and associated with a good prognosis for recovery.

Recurrent severe hypotony after cataract surgery in an eye with previous trabeculectomy

This report describes a patient who developed severe recurrent hypotony after uneventful phacoemulsification and intraocular lens (IOL) implantation 4 years after trabeculectomy. Hypotony was first noticed 1 month postoperatively and treated successfully with topical steroids. However, it reappeared 2 months later and slowly subsided only with steroid and cycloplegic treatment. There was no anterior chamber shallowing, leakage, or signs of inflammation. The cause of hypotony in this patient remains unknown. One possible explanation is subclinical postoperative inflammation as a foreign-body reaction to the IOL.

Vanidilol: a vanilloid-type vasorelaxant and ocular hypotensive beta-adrenoceptor blocker with partial beta-2-agonist activity

Vanidilol, [4'-(2-hydroxy-3-(tert-butylamino)propoxy)-3'-methoxyphenyl] -benzaldehyde, newly synthesized from vanillin, is a vanilloid-type beta-adrenoceptor blocker. The beta-adrenoceptor-blocking properties of vanidilol were studied both in vivo and in vitro. Intravenous injection of vanidilol (1.0, 3.0, 5.0 mg/kg) in anesthetized Wistar rats produced a decrease in blood pressure and a dose-dependent bradycardia response. Vanidilol inhibited the tachycardia effects induced by (-)isoproterenol, but had no blocking effect on the arterial pressor responses induced by phenylephrine. In isolated guinea-pig tissues, vanidilol attenuated the (-)isoproterenol-induced positive chronotropic and inotropic effects of the atria and trachea relaxation responses in a concentration-dependent manner. The parallel shift to the right of the concentration-response curve of (-)isoproterenol suggested that the agent was a beta-adrenoceptor competitive antagonist. The apparent pA2 values for vanidilol on the right atria, left atria and trachea were 7.67 +/- 0.03, 7.89 +/- 1.02 and 7.66 +/- 0.15, respectively, denoting that vanidilol was a nonselective beta-blocker. The intrinsic sympathomimetic activity of vanidilol and propranolol was determined on isolated atria and trachea from reserpinized guinea pigs. Propranolol caused significantly negative inotropic and chronotropic effects at 10(-6) mol/l or above, whereas vanidilol possessed less cardiodepressant activities than propranolol. In reserpinized tracheal strips, vanidilol produced dose-dependent relaxant responses, but propranolol was ineffective. Preincubating the preparations with ICI 118,551 (0.1-10 nmol/l), a beta 2-adrenoceptor antagonist, significantly shifted the concentration-relaxation curves of vanidilol to a region of higher concentrations. In isolated guinea-pig thoracic aorta, vanidilol (0.1-10 mumol/l) inhibited the phenylephrine (10(-5) mol/l)-induced tonic contraction in vascular smooth muscle which was related to the block of calcium influx. In 20% saline-perfused rabbits, vanidilol showed a marked delay in intraocular pressure recovery, demonstrating an ocular hypotensive action. Binding characteristics of vanidilol and propranolol were evaluated in [3H]dihydroalprenolol binding to porcine ventricular membranes. Vanidilol was less potent than propranolol in competing for the beta-adrenoceptor-binding sites. On the other hand, vanidilol had a high hydrophilicity in comparison with propranolol. In conclusion, vanidilol exhibited nonselective beta-adrenoceptor blocking, vasorelaxant and ocular hypotensive activities, but was devoid of alpha-adrenoceptor blocking and beta 1-agonist activity. Partial beta 2-adrenoceptor agonist activity and inhibitory activity on calcium influx may share in the vasorelaxant activity.

Influence of physical exercise and nifedipine on ocular pulse amplitude

BACKGROUND

Ocular pulse amplitude (OPA) was measured to investigate the influence of peripheral vasoconstriction and vasodilation on choroidal perfusion in healthy volunteers and to determine whether low OPA in low-tension glaucoma (LTG) patients is associated with a vasospastic reaction and its response to the calcium channel blocker nifedipine.

METHODS

OPA was determined using the Langham ocular blood flow (OBF) system, applanation intraocular pressure (IOP), systemic blood pressure, and heart rate were measured, and ocular perfusion pressure was calculated before and after exercise and smoking in 12 otherwise nonsmoking, healthy volunteers and prior to and for 3 months after initiation of nifedipine therapy in 32 LTG patients with and without a vasospastic reaction as manifested by a nailfold capillary blood flow test.

RESULTS

Exercise significantly (P < 0.05) increased heart rate, systolic blood pressure and ocular perfusion pressure, while it significantly (P < 0.05) reduced IOP and diastolic blood pressure. However, OPA was not significantly (P > 0.1) affected by changes in these parameters. Smoking significantly (P < 0.05) increased systolic and diastolic blood pressure, heart rate, and ocular perfusion pressure but did not significantly (P > 0.09) alter OPA. There were two distinct LTG subtypes, with and without a vasospastic reaction. Only those with a vasospastic reaction showed a significant (P < 0.001) increase in OPA after 3 months of nifedipine treatment, while all other parameters tested were not significantly altered.

CONCLUSION

Despite affecting ocular and systemic perfusion parameters, exercise and smoking did not alter OPA, suggesting functional isolation, i.e. autoregulation of the choroidal and/or ophthalmic artery circulation in healthy volunteers. Low OPA in LTG was increased by nifedipine only in vasospastic LTG patients, suggesting different, vasotonus-related pathologies. Calcium channel blockers and other vasodilators may be useful in vasoreactive LTG patients with reduced OPA.

Cataract extraction and intraocular lens implantation in eyes with phacomorphic or phacolytic glaucoma

We describe nine patients who had phacomorphic or phacolytic glaucoma. After intraocular pressure (IOP) was reduced medically, all patients had extracapsular cataract extraction. All had intraocular lens implantation except one. The surgery improved visual acuity and resulted in normal IOP in all eyes.

Effects of topically applied prostaglandin F2 alpha on normotensive human eyes

The ocular effects of topical prostaglandin F2 alpha (PGF2 alpha) were studied in normotensive human eyes. PGF2 alpha as tromethamine salt, 100 micrograms, was applied to one eye of 23 normotensive subjects, intraocular pressure (IOP) and pupil size were measured, objective and subjective findings recorded during the first 24 h. Tonography was performed in 10 subjects. As compared with the baseline, PGF2 alpha caused a significant IOP reduction between 1 and 24 h (p < 0.001), being maximal (4.9 +/- 0.5 mm Hg, mean +/- SEM, p < 0.001) between 4 and 8 h. As compared with the contralateral control eyes, which received 50 microliters of saline, treated eyes exhibited significant IOP reduction between 1 and 24 h (p < 0.001), being maximal (4.2 +/- 0.4 mm Hg, mean +/- SEM, p < 0.001) at 4 h. PGF2 alpha caused marked conjunctival hyperemia in all eyes. Pupillary diameter was not altered. Aqueous flare and cellular response were not seen. Half of the subjects complained of ocular smarting, mild ocular pain or headache. Total outflow facility did not change (p > 0.05).

Topical ibopamine and corticosteroids in the treatment of post-surgery ocular hypotony

PURPOSE

The aim of the present preliminary study, performed on post-surgical hypotony, was the evaluation of the effects on ocular hypotony of the concomitant administration of ibopamine and corticosteroids.

METHODS

14 patients (11 males-3 females; mean age 47 years) with ocular hypotony following several vitroretinal surgical intervention in different districts, were enrolled. The inclusion criteria were: mean IOP during tonometric curve equal or lower than 6 mmHg, stable IOP for at least 60 days, ongoing treatment with 0.1% dexamethasone (4 times/day), successful surgical intervention, 2% ibopamine (4 times/day) was added to the corticosteroid therapy for 30-60 days.

RESULTS

Before ibopamine administration, mean IOP was 4.07 mmHg SD 1.71. At the end of the treatment period, mean IOP increased by 89% in comparison to baseline values (+ 3.64 mmHg SD 5.57). This difference was statistically significant (paired t = 2.39; P = 0.03). One month after ibopamine-treatment discontinuation, mean IOP decreased to pre-treatment values (4.86 mmHg SD 3.50).

CONCLUSIONS

The results of the present study, although preliminary, suggest the possibility of a future pharmacological treatment of ocular hypotony with ibopamine, whose rationale is based on the increase of aqueous humor production by stimulating the D1 dopaminergic receptor.

Ocular hypotensive effects of L-arginine and its derivatives and their actions on ocular blood flow

Effects of L-arginine and some related compounds on the intraocular pressure recovery (IOPR) and ocular blood flow in rabbits had been studied. It was found that L-arginine (RVC-579) and N alpha-benzoyl-L-arginine ethyl ester (RVC-578) delayed the IOPR markedly: The IOPR of the contralateral non-treated eye was delayed to the same extent as the treated eye. The effects of closely related congeners L-(+)-canavanine (RVC-581) and L-homoarginine (RVC-580) on the IOPR were qualitatively similar to RVC-579 and RVC-578 but less effective. RVC-578 was found to increase the blood flow significantly in ciliary body, retina and choroid. On the other hand, NG-nitro-L-arginine, a nitric oxide (NO) synthase inhibitor, reduced the blood flow in choroid at 60 and 120 min after drug administration and did not increase the blood flow in iris, ciliary body and retina. These results indicate that L-arginine and its derivative are capable of lowering the IOP possibly through the formation of nitric oxide to relax the blood vessel and to reduce the IOP as a result.

Cyclodialysis cleft following a scleral tunnel incision

We report a case of ocular hypotony secondary to a cyclodialysis cleft that developed following a phacoemulsification procedure in which a scleral tunnel incision was used. A cyclodialysis cleft should be suspected in cases of persistent postoperative hypotony.

Modulation of intraocular pressure by adenosine agonists

Adenosine receptors have been shown to modulate a variety of physiological functions; however, little is known about the role these receptors play in the modulation of ocular function. To investigate the potential role of adenosine receptors in modulating intraocular pressure (IOP), the A1 agonist N6-cyclopentyladenosine (CPA), the nonselective adenosine agonist 5'-N-ethylcarboxamideadenosine (NECA) and the A2 agonist 8-phenylaminoadenosine (CV-1808) were evaluated. Topical administration of NECA produced a dose-related reduction in IOP. However, an initial ocular hypertension of 1 to 2 hours was also observed in rabbits treated with NECA. The administration of CPA (165 micrograms) resulted only in a reduction in IOP, while the administration of CV-1808 produced only an initial ocular hypertension. As adenosine A1 receptors have been shown to be negatively coupled to adenylate cyclase in several systems, CPA was evaluated for its ability to suppress cAMP formation in the isolated iris/ciliary body. CPA produced a dose-related suppression of cAMP accumulation induced by 10(-6) M forskolin (EC50 = 3.2 nM). These results indicate that selected adenosine agonists can modulate IOP. The ocular hypotension induced by adenosine agonists is consistent with the activation of adenosine A1 receptors and may involve the modulation of cAMP levels in the iris/ciliary body.

Studies on the ocular hypotensive effects of prostaglandin F2 alpha ester prodrugs and receptor selective prostaglandin analogs

The use of natural prostaglandins (PG), such as PGD2, PGE2, PGF2 alpha, and PGI2, for treating glaucoma is limited by their ocular side effects. One approach to achieve the required separation of ocular hypotensive activity from side effects is to employ ester prodrugs. From a novel series of 11- and 15-mono and 11,15-diacyl esters of PGF2 alpha we identified prodrugs where PGF2 alpha formation rates in the iris-ciliary body exceeded those in the conjunctiva, sclera, and corneal endothelium. Compared to PGF2 alpha-1-isopropyl ester the ocular tissue hydrolysis rates of the 11-monopivaloyl, the 11,15-dipivaloyl ester and the 1,11-lactone were up to 1000 fold less. Despite this large disparity in hydrolysis rates, the pivaloyl esters and the 1,11-lactone were potent ocular hypotensives in our animal models. In studying prostaglandin analogs, we found that a diverse variety of prostanoid receptor selective agonists lowered intraocular pressure in dogs and/or monkeys. These included DP-, EP1-, EP2-, EP3-, and FP-receptor selective compounds. These findings were surprising and prompted us to re-examine the receptor selectivity of these agonists by radioligand binding studies. Using radiolabelled PGE2, 17-phenyl PGF2 alpha, and sulprostone we were able to confirm the selectivity of the agonists currently used for receptor characterization directly by radioligand binding competition studies. It appears that multiple prostanoid receptor subtypes may be involved in regulating intraocular pressure.

Aqueous humor flow and flare in patients with myotonic dystrophy

PURPOSE

Myotonic dystrophy is an autosomal dominant form of muscular dystrophy associated with a mutation that affects a gene on chromosome 19. Extremely low intraocular pressure is one of a constellation of clinical signs that sometimes accompany this disorder. This study was performed to determine if the ocular hypotony can be explained by aqueous humor hyposecretion.

METHODS

Seventeen persons with myotonic dystrophy and seventeen age-matched controls were studied. Intraocular pressure, light scattering (flare), fluorescein clearance at various times of day, and the response of the eye to the topical timolol were measured.

RESULTS

Intraocular pressure was 40% lower in the persons with myotonic dystrophy (8.4 mm Hg vs 14.0 mm Hg) and flare was 50% higher (55.8 mg/dl albumin equivalent vs 37.1 mg/dl albumin equivalent). Fluorescein clearance in persons with myotonic dystrophy was indistinguishable from normal at all times of day. Myotonic eyes responded normally to topical timolol. The physiological data of this study are most consistent with the conclusion that the rate of aqueous humor flow is reduced approximately 9%, and the rate of inward leakage of light scattering proteins is increased approximately 37% in well-established myotonic dystrophy with ocular hypotony.

CONCLUSIONS

The reduced aqueous humor flow alone is insufficient to explain the ocular hypotony. We hypothesize that the hypotony is due primarily to atrophy of the ciliary muscle that increases fluid exchange between the anterior chamber and the anterior uvea with consequent enhancement of uveoscleral outflow.

Inadvertent cyclodialysis cleft

We report four patients with functionally significant inadvertent cyclodialysis cleft. In three, the cleft followed uneventful extracapsular cataract extraction with posterior chamber intraocular lens implantation; in the fourth, blunt trauma with hyphema. Ocular hypotony resolved in three patients with medical therapy; the fourth required argon laser photocoagulation. Causes, clinical findings, and treatment of inadvertent cyclodialysis cleft are reviewed.

Effect of oxymetazoline on aqueous humor dynamics and ocular blood flow in monkeys and rabbits

OBJECTIVE

To evaluate the ocular effects of oxymetazoline hydrochloride, an alpha 2 agonist, in cynomolgus monkeys and albino rabbits.

METHODS

Intraocular pressure was measured before and for 6 hours after application to glaucomatous monkey eyes. Outflow facility and aqueous flow rates were measured in normal monkey eyes. Uveoscleral outflow was measured in rabbit eyes. Ocular peak pulse volume was determined with the ocular blood flow system in normal and glaucomatous monkey eyes.

RESULTS

Single applications of ozymetazoline reduced (P < .001) intraocular pressure up to 6.0 +/- 1.0 mm Hg (mean +/- SEM). Enhancement of the ocular hypotensive effect was observed with 5-day twice-daily administration. Outflow facility was unaltered; aqueous flow rate was decreased (P < .001) by 39% in the treated eyes compared with baseline values; and uveoscleral outflow was increased (P < .005) by 56% in the treated eye. Peak pulse volume was unchanged.

CONCLUSION

Oxymetazoline reduces intraocular pressure by decreasing aqueous humor flow rates and increasing uveoscleral outflow. Oxymetazoline may have clinical potential as an ocular hypotensive drug.

Studies of topical carbonic anhydrase inhibitors: ocular hypotensive effect of thiadiazole derivatives

A series of thiadiazole derivatives were topically applied in gels or suspensions to rabbits to determine their ocular hypotensive effect. As a result, the compounds with higher corneal permeabilities showed stronger effect in lowering IOP. In addition, gels also caused stronger effect than suspensions. Different concentrations of gel preparations produced diverse ocular hypotensive effects. A linear relationship between the integrated IOP response and logarithm concentration of inhibitor was found. It is proposed that the ocular hypotensive effect was attributed to the level of inhibitor in ciliary body.

New isomeric classes of topically active ocular hypotensive carbonic anhydrase inhibitors: 5-substituted thieno[2,3-b]thiophene-2-sulfonamides and 5-substituted thieno[3,2-b]thiophene-2-sulfonamides

A series of 5-substituted thieno[2,3-b]- and thieno[3,2-b)- and thieno[3,2-b)thiophene-2-sulfonamides was prepared and evaluated for topical ocular hypotensive activity in glaucoma models. The 5-substituents were varied to maximize both inhibitory potency against carbonic anhydrase and water solubility. At the same time, these substituents were varied in order to obtain compounds with the appropriate pKa to minimize pigment binding in the iris. All of these variables were optimized in the best compound, 5-[[(methoxyethyl)[(methoxyethyl)ethyl] amino]methyl]thieno[2,3-b]thiophene-2-sulfonamide hydrochloride (55).

A comparison of L-671,152 and MK-927, two topically effective ocular hypotensive carbonic anhydrase inhibitors, in experimental animals

L-671,152 is a water-soluble, carbonic anhydrase inhibitor structurally similar to MK-927, a carbonic anhydrase inhibitor that, on topical administration, lowers the intraocular pressure (IOP) of experimental animals and humans. L-671,152 was more potent than MK-927 at inhibiting purified, human erythrocyte carbonic anhydrase II in vitro, as reflected in their respective IC50 values of 0.16 nM and 1.19 nM. Both compounds were compared for topical, ocular hypotensive activity in pigmented rabbits and cynomolgus monkeys. Ocular hypertension was induced in the latter by argon laser photocoagulation of the trabecular meshwork. A 2% solution of L-671,152 was more potent than 2% MK-927 in lowering the IOP of ocular hypertensive monkeys, the maximum reductions being 13.8 mm Hg (37%) and 9.6 mm Hg (27%) at 5 hr and 4 hr, respectively. Moreover, the duration of action of L-671,152 was superior to that of MK-927. The ocular hypotensive effect of L-671,152 was greater than that of MK-927 over a range of concentrations (0.5%-2%) in pigmented rabbits whose IOP was inherently elevated. The peak declines in the IOP of these rabbits after the instillation of 2% solutions of L-671,152 and MK-927 were 6.1 mm Hg and 4.8 mm Hg, respectively. L-671,152 was very effective in lowering the elevated IOP of alpha-chymotrypsinized rabbits and the unilateral instillation of 0.5% L-671,152 into the contralateral eye failed to decrease the elevated IOP of the alpha-chymotrypsinized eye. This finding indicates that the site of action of topically applied L-671,152 is local. The enhancement in the potency of L-671,152 over MK-927 is attributed to a greater inhibition of carbonic anhydrase activity.