Effect of neurogenic irritation and calcitonin gene-related peptide (CGRP) on ocular blood flow in the rabbit

The effects of sensory nerve stimulation (topical neutral formaldehyde, 1%) and intracameral injection of calcitonin gene-related peptide (CGRP) on regional ocular blood flow, intraocular pressure (IOP), the blood-aqueous barrier, pupil size, and blood pressure were studied in the rabbit. Sensory nerve stimulation elicited a typical irritative response in the rabbit eye, with vasodilation in the ciliary body (from 128 +/- 31 to 363 +/- 105 mg/min, p less than 0.05) accompanied with a breakdown of the blood-aqueous barrier, rise in the IOP, and miosis. CGRP caused similar, but not identical, changes in the eye: vasodilation in the ciliary body (from 60 +/- 14 to 258 +/- 75 mg/min, p less than 0.05), breakdown of the blood-aqueous barrier and rise in the IOP, accompanied with systemic hypotension. Miosis was not observed after CGRP. In the present study, the vasodilatory action of CGRP on the rabbit eye has been shown. This makes our understanding of the mechanism of the ocular irritative response after sensory nerve stimulation more complete. Thus, CGRP through vasodilation disrupts the blood-aqueous barrier and raises the IOP. The more intense increase in the IOP after sensory nerve stimulation than after CGRP is probably caused by a CGRP-induced vasodilation and breakdown of the blood-aqueous barrier, enhanced by a miosis-induced pupillary block.     

A comparison of CW Nd:YAG contact transscleral cyclophotocoagulation with cyclocryopexy

The cyclodestructive and inflammatory effects of CW Nd:YAG contact laser were compared to those of conventional cryopexy. CW Nd:YAG light transmitted by fiber optic cable and sapphire crystal was applied transsclerally to the ciliary body of pigmented and albino rabbits. Cyclocryopexy was given to a comparable second group. The intraocular pressure (IOP), flare, iritis, cells and conjunctival hyperemia were monitored clinically up to 3 weeks. The breakdown of the blood-aqueous barrier and time course of ocular inflammation was similar for both modalities and IOP was -12.2 +/- 4.2 mm Hg for laser cyclopexy and -15.1 +/- 5.4 mm Hg for cyclocryopexy at 3 weeks. Ciliary body lesions were noted in both groups. Overall, albino rabbits showed less histological damage and faster recovery of IOP. Contact cyclophotocoagulation and cyclocryopexy can be considered models of ocular injury. The similarities in ocular irritative response suggest a similar pathophysiologic mechanism underlying the pressure behavior in both thermal mode injuries.     

Intraocular effects of substance P in the rabbit

The intraocular effects of substance P (SP) were studied in rabbits by measuring the pupil diameter, intraocular pressure (IOP), and aqueous humor protein concentration. Most of the animals were pretreated with indomethacin to avoid any interaction with prostaglandins. Intracameral injection of 1 to 150 ng of SP caused strong and persistent miosis without appreciably affecting the aqueous humor protein concentration or IOP. Intracameral injection of 0.8 to 11 micrograms of SP also induced an increase in IOP (7 to 8 mm Hg) without any apparent concomitant disruption in the blood-aqueous barrier. Outflow facility of aqueous humor decreased by a mean value of 50% after intracameral injection of 0.8 to 1.5 microgram of SP. Since the increase in IOP could be prevented by iridectomy, it was probably caused by a pupillary block from the intense miosis induced by SP. No disruption in the blood-aqueous barrier could be detected after intra-arterial infusion of 10 micrograms of SP or intravitreal injection of 100 ng of SP, indicating that the ciliary epithelium was practically insensitive to exogenous SP. Topical as well as subconjunctival administration of up to 1 mg of SP did not cause any irritative response in the eye. The results show that with concentrations of SP causing intense miosis, the eye does not exhibit visible hyperemia and disruption of the blood-aqueous barrier. This finding is consistent with the hypothesis that after certain irritative stimuli, miosis is mediated by a pathway separate from the hyperemia and disruption of the blood-aqueous barrier.     

CGRP in relation to neurogenic inflammation and cAMP in the rabbit eye

The effects of topical application of neutral formaldehyde (1%) and intracameral administration of calcitonin gene-related peptide (CGRP, 0.5- or 2.0 micrograms) on the intraocular pressure (IOP), blood-aqueous barrier, pupil size, blood pressure and cyclic AMP (cAMP) content in the aqueous humour of a rabbit were studied. Topical chemical irritation with 1% formaldehyde caused a typical irritative response in the eye with a rise in the IOP, breakdown of the blood-aqueous barrier and miosis. The cAMP content in the aqueous humour was also increased (88.5 +/- 35.0 pmol ml-1, P less than 0.05) when compared with the control group (16.3 +/- 3.6 pmol ml-1). Intracameral administration of CGRP caused a rise in the IOP, breakdown of the blood-aqueous barrier and also systemic hypotension. Miosis was not observed after intracameral CGRP but an increase in the cAMP content in the aqueous humour was seen (130.5 +/- 30.3- and 158.7 +/- 48.1 pmol ml-1, both P less than 0.01, after 0.5 or 2.0 micrograms, respectively). The cAMP concentration in the aqueous humour after topical chemical irritation and intracameral CGRP correlated with the intensity of the breakdown of the blood-aqueous barrier. CGRP seems to cause most, but not all, of the ocular changes after sensory nerve stimulation elicited by topical neutral formaldehyde. Of these CGRP-induced changes, only the breakdown of the blood-aqueous barrier is related to an increase in the cAMP content in the aqueous humour. Contralateral responses after sensory nerve stimulation were similar to contralateral responses to intracameral CGRP.     

Effect of bimatoprost on intraocular pressure in prostaglandin FP receptor knockout mice

PURPOSE: To determine the effect of bimatoprost on intraocular pressure in the prostaglandin FP receptor knockout mouse. METHODS: The IOP response to a single 1.2-microg (4 microL) dose of bimatoprost was measured in the treated and untreated fellow eyes of homozygote (FP+/+, n = 9) and heterozygote (FP+/-, n = 10) FP-knockout mice, as well as in wild-type C57BL/6 mice (FP+/+, n = 20). Serial IOP measurements were also performed after topical bimatoprost in a separate generation of homozygous FP-knockout mice and wild-type littermate control animals (n = 4 per group). Aqueous humor protein concentrations were measured to establish the state of the blood-aqueous barrier. Tissue, aqueous humor and vitreous concentrations of bimatoprost, latanoprost, and their C-1 free acids were determined by liquid chromatography and tandem mass spectrometry. RESULTS: A significant reduction in IOP was observed in the bimatoprost-treated eye of wild-type mice at 2 hours, with a mean difference and 95% confidence interval (CI) of the difference in means of -1.33 mm Hg (-0.81 to -1.84). Bimatoprost did not lead to a significant reduction in IOP in either the heterozygous knockout -0.36 mm Hg (-0.82 to +0.09) or homozygous FP-knockout mice 0.25 mm Hg (-0.38 to +0.89). The lack of an IOP response in the FP-knockout mice was not a consequence of blood-aqueous barrier breakdown, as there was no significant difference in aqueous humor protein concentration between treated and fellow eyes. Tissue and aqueous humor concentrations of bimatoprost, latanoprost, and their C-1 free acids indicate that latanoprost, but not bimatoprost, is hydrolyzed in the mouse eye after topical administration. CONCLUSIONS: An intact FP receptor gene is critical to the IOP response to bimatoprost in the mouse eye.     

Relation between office intraocular pressure and 24-hour intraocular pressure in patients with primary open-angle glaucoma treated with a combination of topical antiglaucoma eye drops

PURPOSE: To determine the relation between office intraocular pressure (IOP) and 24-hour IOP in patients with primary open-angle glaucoma (POAG) treated with 3 kinds of antiglaucoma eye drops. PATIENTS AND METHODS: Subjects were 42 patients with POAG (71 eyes). All were being treated with 3 different topical antiglaucoma eye drops (latanoprost, beta-blocker, and carbonic anhydrase inhibitor). Twenty-four-hour IOP values were obtained in the sitting position with a Goldmann applanation tonometer at 3-hour intervals. RESULTS: Maximum 24-hour IOP (mean+/-SD) was 19.76+/-5.65 mm Hg, minimum 24-hour IOP was 13.06+/-4.75 mm Hg, mean 24-hour IOP was 16.30+/-4.90 mm Hg, and 24-hour IOP fluctuation was 6.70+/-2.81 mm Hg. Office IOP was 16.23+/-4.58 mm Hg, and office IOP fluctuation was 2.75+/-1.68 mm Hg. There was no significant difference between office IOP and mean 24-hour IOP (P=0.93). There was no correlation between office IOP and 24-hour IOP fluctuation (r=0.15; P=0.25) or between office IOP fluctuation and 24-hour IOP fluctuation (r=0.19; P=0.17). Maximum 24-hour IOP occurred during office hours in 22 eyes (33.8%). The frequency of maximum 24-hour IOP occurring during office hours was significantly less than that of minimum 24-hour IOP (P<0.001). CONCLUSIONS: In POAG patients treated with 3 kinds of antiglaucoma eye drops, office IOP was similar to mean 24-hour IOP. However, it was difficult to estimate 24-hour IOP fluctuation and maximum 24-hour IOP on the basis of office IOP.     

Comparison of low-dose intraoperative mitomycin-C vs 5-fluorouracil in primary glaucoma surgery: a pilot study

BACKGROUND AND OBJECTIVE: This study was undertaken to compare the efficacy and safety of low-dose intraoperative application of mitomycin-C (MMC) with that of 5-fluorouracil (5-FU) in primary trabeculectomy. PATIENTS AND METHODS: A non-randomized prospective study was performed between August 1994 and November 1995. Thirty-two eyes of 16 consecutive patients who underwent trabeculectomy for uncontrolled glaucoma of various causes form the study group. The mean age was 46.8 +/- 9.9 years. The first eye received MMC (0.2, 0.4 mg/ml), fellow eye received 5-FU (50 mg/ml), for 1 minute intraoperatively. Bleb characteristics and intraocular pressure (IOP) control were analyzed. Success of surgery based on IOP control was measured by 3 different criteria: IOP less than 21 mm Hg; IOP less than 21 mm Hg with more than 30% reduction; and IOP less than 16 mm Hg with more than 30% reduction. RESULTS: Mean preoperative IOP was 31.4 +/-12.7 mm Hg in MMC group and 27.8+/- 8.8 mm Hg in 5-FU group. Mean follow-up in MMC group was 16.12 +/- 8.17 months; in 5-FU group 13.37 +/- 8.19 months. At last follow-up all 5-FU blebs were nonischemic, while 4 eyes in the MMC group showed nonischemic blebs, and 12 eyes had ischemic blebs. There was no statistically significant difference between MMC group and 5-FU group success rates with all 3 criteria. Success rates were: IOP less than 21 mm Hg; 100% in both groups; IOP less than 21 mm Hg with more than 30% reduction; MMC group 93.8%, 5-FU group 75%; less than 16 mm Hg with more than 30% reduction; MMC group 87.5%, 5-FU group 68.8%. CONCLUSIONS: Low-dose intraoperative MMC and 5-FU can provide control of IOP in primary trabeculectomy, 5-FU group showed more non-ischemic blebs.     

Ocular irritative response to YAG laser capsulotomy in rabbits: release of calcitonin gene-related peptide and effects of methysergide.

The Neodymium (Nd):YAG laser is commonly used in ophthalmology mainly for the posterior capsulotomy in patients with secondary cataract after extracapsular cataract extraction. A frequent side-effect following different kinds of YAG laser treatments is an acute increase in the intraocular pressure (IOP). The present study addresses the role of calcitonin gene-related peptide (CGRP) in the ocular irritative response following YAG laser anterior capsulotomy in rabbits. The YAG laser anterior capsulotomy caused an irritative response in the eye, which consisted of an increase in the IOP, miosis and breakdown of the blood-aqueous barrier. Following YAG laser capsulotomy, CGRP-immunoreactivity was found in the aqueous humour in different molecular weight forms as revealed by gel-permeation chromatography. One of the peaks coeluted with synthetic human CGRP. Methysergide attenuated the increase in the IOP and disruption of the blood-aqueous barrier, but not the miosis, following YAG laser anterior capsulotomy. The present study demonstrates the release of CGRP into the aqueous humour following YAG laser capsulotomy, and suggests that CGRP is partly causing the increase in IOP and disruption of the blood-aqueous barrier in this irritative response.     

A comparison of dorzolamide-timolol combination versus the concomitant drugs

PURPOSE: To compare the intraocular pressure (IOP) lowering effect of fixed combination dorzolamide 2% and timolol 0.5% therapy to that of concomitant administration of a topical beta-blocker and dorzolamide. METHODS: Seventy-four consecutive glaucoma patients were changed from a regimen including a topical beta-blocker and dorzolamide to the fixed combination dorzolamide-timolol in 1 eye, with the other eye used as the control. The average IOP readings before and 1 month after the change were compared. RESULTS: The mean baseline IOP in the entire study population was 19.4 +/- 4.2 mm Hg in the study eyes and 16.9 +/- 4.2 mm Hg in the control eyes. Four weeks after the medication change, the mean IOP was 17.3 +/- 3.9 mm Hg in the study eyes (P <.001) and 16.1 +/- 4.1 mm Hg in the control eyes (P =.02). The difference between the mean IOP change of 2.1 mm Hg in the study eyes and 0.8 mm Hg in the control eyes was found to be statistically significant (P =.01). CONCLUSION: These findings suggest that the fixed combination dorzolamide-timolol therapy achieves additional lowering of the intraocular pressure compared with the concomitant administration of a beta-blocker and dorzolamide.     

Postjunctional adrenergic receptors in the rabbit eye: effects on uveal flow and intraocular pressure in isolated arterially perfused eyes

In uveal vessels of isolated arterially perfused rabbit eyes there is direct evidence for the presence of post-junctional alpha 1-receptors and indirect evidence for alpha 2-receptors. Since vasoconstriction by epinephrine could not be blocked by an alpha 1-antagonist, only 30% by an alpha 2-antagonist and almost fully by the combination or by phentolamine, we suggest the presence of an intermediate alpha-type receptor which is neither alpha 1 nor alpha 2 but has characteristics of either. All alpha-types produce vasoconstriction and a fall in IOP. Of the beta-types only beta 1-receptors can be demonstrated. They mediate vasodilatation and a rise in IOP. Neither beta 2- nor non-selective beta-agonists or -antagonists (e.g. timolol) affect IOP or uveal flow.     

The effect of trabeculectomy on the intraocular pressure of the unoperated fellow eye

PURPOSE: To investigate the intraocular pressure (IOP) changes in the unoperated fellow eye in patients who underwent trabeculectomy. MATERIALS AND METHODS: IOP changes in the unoperated fellow eyes of 107 patients who underwent trabeculectomy in 1 eye for high-tension glaucoma (48 primary open-angle glaucoma, 43 pseudoexfoliative glaucoma, and 16 narrow-angle glaucoma) were evaluated during the early postoperative period. All IOP measurements were recorded during the postoperative first 3 months and compared with preoperative values. RESULTS: Mean preoperative IOP levels were 37.0 +/- 10.0 mm Hg in the operated eyes and 15.1 +/- 3.1 mm Hg in the fellow eyes. Mean IOPs in the unoperated eyes on the postoperative first-day, first- and second-week, and first- and third-month visits (17.1 +/- 5.7, 17.5 +/- 5.1, 18.5 +/- 5.4, 18.6 +/- 5.1, and 19.0 +/- 5.9 mm Hg, respectively) were significantly different compared with the preoperative levels for each period of time (P < 0.01). Eight fellow eyes underwent operations for uncontrolled glaucoma before month 3. Among the remaining 99 eyes, higher postoperative IOP values were measured in 33 (33%) eyes at all postoperative visits compared with the preoperative IOP levels. A consistent IOP rise equal to or higher than 5 mm Hg was detected in 12 eyes (12%) and a consistent IOP elevation of 30% or more was found in 14 eyes (14%) during the postoperative first 3 months. Contralateral IOP elevation was not correlated with patient age, type of glaucoma, or preoperative antiglaucomatous medications prescribed to the operated or fellow eyes. CONCLUSION: After filtration surgery, IOP of the unoperated fellow eye should also be monitored closely in order not to overlook a possible insidious rise, especially in glaucomatous eyes that were previously under good medical control.     

Tono-Pen versus Goldmann tonometry after excimer laser photorefractive keratectomy

PURPOSE: To compare intraocular pressure (IOP) measurements by the Tono-Pen 2 tonometer and Goldmann applanation tonometer (GAT) in post-photorefractive keratectomy (PRK) patients. SETTING: Refractive Surgery Center, Assaf Harofeh Medical Center, Zerifin, Israel. METHODS: In 18 patients, IOP was measured by GAT and then by Tono-Pen 2 tonometer 2 to 18 months following PRK (mean 6.6 months +/- 5.1 [SD]). Photorefractive keratectomy had been performed in 1 eye of each patient; the fellow eyes served as controls. Corneal curvature and thickness were evaluated. Ten of the 18 patients were treated with topical steroids. RESULTS: In the post-PRK eyes, mean GAT IOP was 1.8 +/- 3.1 mm Hg lower than mean Tono-Pen IOP (P = .012); there was no significant IOP difference in the control (fellow) eyes. In steroid-treated post-PRK eyes, mean GAT IOP (12.2 mm Hg) was 2.2 +/- 1.3 mm Hg lower than mean Tono-Pen IOP (14.4 mm Hg) (P = .0007). Mean Tono-Pen IOP in steroid-treated post-PRK eyes was 4.3 +/- 3 mm Hg higher than in the fellow eyes (P = .0014); mean GAT IOP was only 2.3 +/- 3.5 mm Hg higher (P = .04). In post-PRK eyes without topical steroid treatment, mean GAT IOP was 2.0 +/- 1.18 mm Hg lower than in the fellow eyes (P = .001); there was no significant difference in Tono-Pen IOP. There was a negative correlation between the difference in IOP values (Tono-Pen minus GAT) and corneal curvature in post-PRK eyes (r = 0.76, P = .0108, n = 15). CONCLUSIONS: The Tono-Pen tonometer appeared to be less affected than the GAT by the relative flattening, thinning, and anterior stromal decreased rigidity of the central cornea that occur following PRK. Post-PRK steroid-induced IOP elevation may be masked by the artifactual decrease in GAT IOP.     

Timolol/dorzolamide combination therapy as initial treatment for intraocular pressure over 30 mm Hg

PURPOSE: To determine the intraocular pressure (IOP)-lowering effect of a fixed timolol/dorzolamide combination (Cosopt) for patients with IOP over 30 mm Hg. STUDY DESIGN: Prospective interventional case series. METHODS: Eighteen patients being seen on the Wills Eye Hospital Glaucoma Service with at least one eye with an IOP > 30 mm Hg were recruited. None had used any glaucoma medications for at least 1 month. IOP was confirmed by diurnal testing. Cosopt was administered at 9 am and 9 pm. Trough IOP measurements were made at 9 am and peak IOP measurements at 11 am at baseline, 1 month, and 2 months. Pretreatment and posttreatment IOPs were compared using a paired-samples independent t test. RESULTS: Mean pretreatment IOP was 37.5 +/- 1.0 mm Hg. Baseline posttreatment IOP was 18.4 +/- 0.5 mm Hg (P < 0.01). At 2 months, the mean trough IOP was 21.1 +/- 0.9 mm Hg and the peak, 17.6 +/- 0.6 mm Hg (each, P < 0.01, as compared with pretreatment baseline IOP). One patient did not respond to Cosopt; two had a clinically insufficient response and did not complete the study. Data from these patients were included in the analysis. CONCLUSIONS: Over 80% of the eyes responded to Cosopt, with an average trough IOP reduction of 40% at 2 months.     

Intraindividual comparison of the effects of a fixed dorzolamide-timolol combination and latanoprost on intraocular pressure after small incision cataract surgery

To compare the effect of a fixed dorzolamide-timolol combination with that of latanoprost on intraocular pressure (IOP) after small incision cataract surgery.Department of Ophthalmology, University of Vienna, Vienna, Austria.This prospective randomized study comprised 60 eyes of 30 patients scheduled for small incision cataract surgery in both eyes. The patients were randomly assigned to receive 1 drop of a fixed dorzolamide-timolol combination or latanoprost immediately after cataract surgery in the first eye. The second eye received the other antiglaucomatous agent. Cataract surgery was performed under sodium hyaluronate 1% with a temporal 3.5 mm sutureless posterior limbal incision, phacoemulsification, and implantation of a foldable intraocular lens. The IOP was measured preoperatively as well as 6 and 20 to 24 hours and 1 week postoperatively.Six hours after surgery, the mean IOP decreased by -0.8 mm Hg +/- 3.2 (SD) (P =.184) in the dorzolamide-timolol group and increased by 3.6 mm Hg +/- 3.5 (P <.001) in the latanoprost group. Twenty to 24 hours after surgery, the mean IOP decreased by -2.8 +/- 2.4 mm Hg (P <.001) in the dorzolamide-timolol group and increased by 0.6 +/- 3.5 mm Hg (P =.353) in the latanoprost group. The differences between groups were significant at 6 hours (P <.001) and 20 to 24 hours (P <.001).The fixed dorzolamide-timolol combination was more effective than latanoprost in reducing IOP after small incision cataract surgery. Only the fixed dorzolamide-timolol combination prevented a postoperative IOP increase and occasional IOP spikes of 30 mm Hg or higher.     

Methazolamide 1% in cyclodextrin solution lowers IOP in human ocular hypertension

PURPOSE: To formulate aqueous eye drops containing methazolamide 1% in cyclodextrin solution and to evaluate their effect on intraocular pressure (IOP) in a double-blind randomized trial in humans. Methazolamide, a carbonic anhydrase inhibitor (CAI), has been used in oral doses in the treatment of glaucoma but hitherto has not been successfully formulated in eye drops. In this study the effects of methazolamide are compared with those of dorzolamide (Trusopt). METHODS: Methazolamide 1% was formulated in a 2-hydroxypropyl-beta-cyclodextrin with hydroxypropyl methylcellulose in aqueous solution. Eight persons with ocular hypertension were treated with the methazolamide-cyclodextrin eye drops and eight persons with dorzolamide (Trusopt), both groups at dosages of three times a day for 1 week. IOP was measured before treatment was begun and on days 1, 3, and 8 at 9 AM (peak) and 3 PM (trough). RESULTS: After 1 week of treatment, the peak IOP in the methazolamide group had decreased from 24.4 +/- 2.1 mm Hg (mean +/- SD) to 21.0 +/- 2.0 mm Hg, which is a 14% pressure decrease (P: = 0.006). In the dorzolamide group, the peak IOP decreased from 23.3 +/- 2.1 mm Hg to 17.2 +/- 3.1 mm Hg, which is a 26% pressure decrease (P: < 0.001). On average, the IOP declined 3.4 +/- 1.8 mm Hg after methazolamide administration and 6.1 +/- 3.6 mm Hg after dorzolamide. CONCLUSIONS: Through cyclodextrin complexation, it is possible to produce topically active methazolamide eye drops that lower IOP. This is the first double-blind clinical trial that demonstrates the efficacy of the classic CAIs in eye drop formulation.     

Prostaglandin analogs and blood-aqueous barrier integrity: a flare cell meter study

PURPOSE: To study, with an objective method, inflammation of the anterior segment of the glaucomatous eye after treatment with latanoprost, travoprost and bimatoprost. MATERIALS AND METHODS: Sixty patients with chronic open-angle glaucoma aged between 38 and 76 years (mean 64.0 +/- 12.2) were randomly assigned to latanoprost 0.005, travoprost 0.004 and bimatoprost 0.03%. The study period lasted 6 months. Intraocular pressure (IOP) was measured every 2 weeks. We studied the intraocular inflammation before and after 3 and 6 months of therapy with an instrument composed of a He-Ne laser beam system, a photomultiplier mounted on a slitlamp microscope and a computer. This flare meter allows objective determination of the flare and the number of cells in the aqueous of the anterior chamber. RESULTS: At the baseline, IOP was 26.4 +/- 3.6 mm Hg. After 3 months of treatment, mean IOP in the latanoprost group was 17.9 +/- 0.3 mm Hg (p < 0.001) with a mean cellularity of 12.638 +/- 3.284 photons/ms (p < 0.001). The travoprost group had an IOP of 17.2 +/- 0.3 mm Hg (p < 0.001) with a cellularity of 9.719 +/- 1.927 photons/ms (0.001). Finally, IOP in the bimatoprost group was 17.6 +/- 0.5 mm Hg (p < 0.001) with a cellularity of 6.138 +/- 1.475 photons/ms (p < 0.032). After 6 months of treatment, IOP in the latanoprost group was 18.1 +/- 0.3 (p < 0.001), in the travoprost group 17.3 +/- 0.3 (p < 0.001) and in the bimatoprost group 17.7 +/- 0.5 mm Hg (p < 0.001), whereas cellularity was 11.838 +/- 3.218 (p < 0.001), 8.950 +/- 3.692 (p < 0.001) and 7.617 +/- 2.603 photons/ms (p < 0.001), respectively. After 3 months, the travoprost (p < 0.013) and the bimatoprost groups (p < 0.001) had less flare compared with the latanoprost group and this remained so even at 6 months. When we compared the travoprost group with the bimatoprost group, we found significantly less flare at 3 months in the bimatoprost group (p < 0.001) but not at 6 months (p < 0.246). CONCLUSIONS: The flare meter analysis shows that the eyes treated with bimatoprost and travoprost have a less significantly broken blood-aqueous barrier and their anterior chamber is also significantly less inflamed.     

Effect of dorzolamide and latanoprost on intraocular pressure after small incision cataract surgery

PURPOSE: To evaluate the effect of dorzolamide 2% and latanoprost 0.005% on intraocular pressure (IOP) after small incision cataract surgery. SETTING: Department of Ophthalmology, University of Vienna, Vienna, Austria. METHODS: This prospective study comprised 102 eyes of 102 consecutive patients scheduled for small incision cataract surgery. The patients were assigned preoperatively to 1 of 3 groups of 34 each: dorzolamide, latanoprost, and control (no treatment). One drop of the assigned medication was instilled immediately after surgery. Intraocular pressure was measured preoperatively and 6 and 20 to 24 hours postoperatively. RESULTS: Six hours after surgery, the mean increase in IOP was 1.9 mm Hg +/- 3.9 (SD) in the dorzolamide group (P = .004 versus control), 2.2 +/- 3.0 mm Hg in the latanoprost group (P = .005 versus control), and 4.8 +/- 5.2 mm Hg in the control group. Twenty to 24 hours postoperatively, IOP decreased a mean of -0.9 +/- 3.5 mm Hg in the dorzolamide group (P = .012 versus control) and increased a mean of 0.3 +/- 3.6 mm Hg in the latanoprost group (P = 0.24 versus control) and 1.3 +/- 4.2 mm Hg in the control group. One eye in the dorzolamide group, 1 eye in the latanoprost group, and 4 eyes in the control group had an IOP of 30 mm Hg or higher 6 hours postoperatively. CONCLUSION: Six hours postoperatively, dorzolamide and latanoprost were effective in reducing the IOP increase after small incision cataract surgery; however, at 20 to 24 hours, only dorzolamide was effective. Neither drug prevented IOP spikes of 30 mm Hg or higher.     

Evaluation of intraocular pressure in the immediate period after phacoemulsification

PURPOSE: To determine the incidence of hypotony or intraocular pressure (IOP) spikes in the early period after clear corneal phacoemulsification in normal and glaucomatous eyes. SETTING: Ambulatory surgical center. METHODS: This retrospective analysis comprised 112 eyes that had clear corneal phacoemulsification. Postoperative IOP measurements were collected 30 minutes, 1 day, and 1 month after surgery. RESULTS: Twenty-three eyes had an IOP of 5 mm Hg or below 30 minutes postoperatively. The IOP at 30 minutes was lower than at 1 day in both the normal and the glaucoma group. The mean IOP in the normal group was 10.0 mm Hg +/- 4.3 (SD) at 30 minutes and 16.9 +/- 4.4 mm Hg at 1 day (P < or = .005). The means in the glaucoma group were 9.6 +/- 3.9 mm Hg and 16.9 +/- 5.7 mm Hg, respectively (P < or = .0002). The IOPs at 30 minutes and 1 day were not significantly different between the 2 groups. CONCLUSIONS: A significant percentage of eyes having clear corneal phacoemulsification had an IOP of 5 mm Hg or less 30 minutes after surgery. Even though there were no postoperative complications from hypotony and there was a relative absence of significant IOP elevation 1 day postoperatively, the frequency of low IOP at 30 minutes suggests that consideration be given to leaving postoperative eyes with a higher IOP at the completion of phacoemulsification rather than with the estimated 10 mm Hg tactile IOP strived for in this study.     

Seven-year follow-up of combined cataract extraction and viscocanalostomy

PURPOSE: To investigate the long-term success and complications of phacoemulsification combined with viscocanalostomy (phacoviscocanalostomy) in eyes with coexisting cataract and medically uncontrolled glaucoma. SETTING: Department of Ophthalmology, Warrington Hospital, Warrington, United Kingdom. METHODS: A prospective nonrandomized study evaluated 165 consecutive eyes (114 patients) that had phacoviscocanalostomy. The main outcome measures were intraocular pressure (IOP), visual acuity, requirement for topical antiglaucoma medication, and the presence or absence of drainage blebs or bleb complications. RESULTS: The mean follow-up was 38.7 months +/- 19.3 (SD) (range 12 to 90 months). There was a statistically significant decrease in IOP, from 24.1 +/- 5.1 mm Hg preoperatively to 13.8 +/- 8.1 mm Hg 1 day after surgery (P<.001), 16.0 +/- 4.1 mm Hg at 5 years (P<.001), and at all evaluations to the last follow-up. The mean number of medications per eye decreased significantly from 2.5 +/- 0.9 before surgery to 0.1 +/- 0.5 at last follow-up (P<.001). At the final follow-up, IOP was reduced by 33.2% (16.2 mm Hg versus 24.1 mm Hg). Complete success, defined as an IOP reduction of more than 30% from preoperative level without medications, was achieved in 48.5% of eyes, with 42% of eyes having an IOP of less than 16 mm Hg. The percentage fall in IOP was linearly related to the preoperative IOP level (P<.001). No eye developed a trabeculectomy-type bleb, and there were no bleb-related complications. CONCLUSIONS: Phacoviscocanalostomy was safe and effective for the management of eyes with coexisting cataract and medically uncontrolled glaucoma. It provided a stable and sustained reduction in IOP with a minimum requirement for topical medication.     

A study of the mechanism of ocular irritation following YAG laser capsulotomy in rabbits

The irritative response to Nd:YAG laser capsulotomy was studied in unanaesthetized rabbits. Posterior lens capsulotomy with a total energy of 100 mJ had no effect on the pupil size but increased the intraocular pressure by 5-10 mmHg and caused a breakdown of the blood-aqueous barrier. Anterior lens capsulotomy with a total energy of 20, 60 or 100 mJ caused constriction of the pupil, and an increase in intraocular pressure in a dose-dependent manner, and a breakdown of the blood-aqueous barrier. Indomethacin attenuated all the component parts of the irritative response and (D-arg1, D-pro2, D-trp7,9, leu11)-SP attenuated the miotic response. A combination of indomethacin and the substance P antagonist almost completely abolished the irritative response. This indicates that the acute YAG-laser-induced irritation in the rabbit eye is dependent both on a release of prostaglandins and on substance P, the former probably releasing the latter from sensory nerves.