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Pilocarpine-induced shift of an accommodating intraocular lens: AT-45 Crystalens.

PURPOSE: To measure the shift of an accommodating plate-haptic intraocular lens (IOL) along the visual axis induced by ciliary muscle contraction after application of pilocarpine. SETTING: Department of Ophthalmology, Medical University of Vienna, Vienna, Austria. METHODS: Fifty-four eyes of 28 patients with age-related cataract comprised this prospective study. Each patient received an AT-45 silicone accommodating IOL (Crystalens, Eyeonics Corp.) after standardized cataract surgery. In a subgroup of 24 eyes, capsular bag fibrosis was reduced by extensive polishing of the anterior capsule with a slit cannula. Assessment included measurements of anterior chamber depth, assessed with partial coherence interferometry, before and after application of pilocarpine 2% and evaluation of near visual acuity 1 month and 3 months postoperatively. RESULTS: A slight backward shift of the IOL of 151 mum in the nonpolished group (P < .001) and 122 mum in the polished group (P < .005) could be detected after application of pilocarpine. Polishing the capsule did not influence IOL shift. The median near visual acuity with distance correction 1 month and 3 months postoperatively was J5 and J4, respectively, in the nonpolished group and J6 at both times in the polished group. CONCLUSIONS: Pilocarpine induced a counterproductive active backward shift of the AT-45 IOL. Polishing of the capsular bag had no impact on accommodative ability. The reading performance of patients with the AT-45 IOL patients at 1 and 3 months was not significantly different from that of with a standard IOL under similar testing methods.

Accommodation, Ocular↗

A vision of our own.

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Accommodation, Ocular↗

Objective measurement of intraocular lens movement and dioptric change with a focus shift accommodating intraocular lens.

PURPOSE: To objectively measure the shift and refractive change of the 1CU accommodating intraocular lens (IOL) (HumanOptics) and compare them to that of a monofocal AcrySof MA30 IOL (Alcon Laboratories) in the fellow eye. SETTING: Ophthalmology Department, St. Thomas' Hospital, London, United Kingdom. METHODS: Thirty patients who had bilateral cataract surgery 18 to 24 months previously with a 1CU IOL prospectively randomly allocated to 1 eye and an AcrySof MA30 monofocal IOL to the other eye were examined. Distance correction, near vision, reading fluency, near point, and defocus to minus spheres were measured. Intraocular lens shift to an accommodative stimulus following instillation of pilocarpine 4% was measured with the ACMaster. Refractive change between distance and near was measured with the Tracey wavefront analyzer. RESULTS: Of the original 30 patients recruited, complete measurements could only be obtained for 20. There was no significant difference in near visual function with either IOL. A small anterior movement of the 1CU was seen with accommodation 0.010 mm +/- 0.028 (SD). After pilocarpine 4% instillation, a forward movement of 0.220 +/- 0.169 mm was seen with the 1CU compared to a backward movement of 0.028 +/- 0.095 with the MA30. There was no significant correlation between distance corrected near visual acuity and IOL movement. No change in spherical equivalent between distance and near was seen on wavefront analysis of either IOL. CONCLUSIONS: Small forward movement of the 1CU IOL was seen with accommodation and increased following pilocarpine, compared to the posterior movement of the MA30 IOL. The amount of the IOL shift was not sufficient to provide useful near vision, but the difference suggests that the engineering concept behind the 1CU IOL is valid.

Accommodation, Ocular↗

An uncommon presentation of acute angle closure glaucoma.

Acute angle closure glaucoma is an ocular emergency that is treatable with prompt and appropriate intervention. Recognition of this disease entity is sometimes difficult. We report a case of bilateral acute angle closure glaucoma in a 55-year-old, otherwise healthy individual, and discuss the different ways the condition may present. The anatomic and pathophysiologic progression leading to an event of angle closure is discussed and treatment modalities available to the Emergency Physician are presented.

Acetazolamide↗

Anhidrosis: a clue to an underlying autonomic disorder.

We describe a patient with Ross syndrome who had the classic triad of segmental anhidrosis, tonic pupils and hyporeflexia. Dilute pilocarpine (0.1%) instillation in both eyes revealed parasympathetic denervation hypersensitivity. There was evidence of cardiac dysautonomia in the form of a decrease in heart rate variability with deep breathing and an abnormal Valsalva response. A thermoregulatory sweat test showed the presence of sweating in the right cheek, neck and upper one-third of the left arm and shoulder only. Sympathetic skin responses were absent in the affected segments of the upper limb. Ross syndrome is a degenerative disorder that progressively involves different fibre populations, starting with autonomic fibres and then involving the unmyelinated and myelinated sensory fibres. A careful clinical examination and simple bedside autonomic tests can confirm the diagnosis.

Adult↗

Effect of accommodation and pupil size on the movement of a posterior chamber lens in the phakic eye.

PURPOSE: Although a posterior chamber phakic intraocular lens provides effective refractive correction of high myopia and hyperopia, mechanical contact between the implantable contact lens (ICL) and the crystalline lens and inadequate aqueous circulation in the prelenticular space could cause subcapsular opacification. To assess whether and to what extent such mechanical contact occurs, changes in the distance between the STAAR Collamer ICL and the crystalline lens under various conditions were investigated. DESIGN: Open pilot study. PARTICIPANTS: Thirteen eyes of 11 myopic and 2 hyperopic patients with a mean age of 38 years (range, 19-53 years) were examined at least 6 months after ICL implantation. METHODS: A noninvasive, high-resolution biometry technique, partial coherence interferometry, was used to measure distance changes between the ICL and the crystalline lens during subjective accommodation, after instillation of pilocarpine, and under changing light conditions. MAIN OUTCOME MEASURES: Mean distance changes from the posterior corneal surface to the ICL, from the posterior corneal surface to the anterior surface of the crystalline lens, and the distance between the ICL and the crystalline lens. RESULTS: In the nonaccommodated state, the mean distance between the ICL and the crystalline lens was 457 microm (range, 123-924 microm). During subjective accommodation, a significant (P<0.01) decrease and, after topical application of pilocarpine, a nonsignificant (P=0.35) decrease of anterior chamber depth was accompanied by a nonsignificant (P = 0.71) reduction of the ICL-crystalline lens distance. Under photopic conditions, a significant mean reduction (P<0.01) of the ICL-crystalline lens distance of -28 microm (range, -16 to -188 microm) was observed. CONCLUSIONS: Partial coherence interferometry biometry enabled noninvasive high-precision investigation of ICL dynamics. No significant changes between the ICL and the crystalline lens were detected during subjective accommodation and after application of pilocarpine. However, under photopic conditions, with constriction of the pupil, the distance between the ICL and the crystalline lens was significantly reduced. This mechanism might cause inadequate aqueous circulation in the prelenticular space and might be one of the causes of subcapsular opacification in some of the eyes after ICL implantation.

Accommodation, Ocular↗

Laserinterferometric assessment of pilocarpine-induced movement of an accommodating intraocular lens: a randomized trial.

PURPOSE: To measure the axial movement of an accommodating intraocular lens (IOL) induced by ciliary muscle contraction after application of pilocarpine. DESIGN: Randomized, controlled, patient- and examiner-masked trial with intrapatient comparison. PARTICIPANTS AND CONTROLS: One hundred ten eyes of 55 patients with age-related bilateral cataract. METHODS: This study was divided into 3 parts. In the first, the accommodating IOL (1CU) was compared with a 3-piece open-loop acrylic IOL that served as the control. In the second, to assess the effect of capsule fibrosis on the potential accommodating performance of the accommodating IOL, extensive polishing of the anterior capsule with a slit cannula was compared with standard surgery. In the third, the effect of a posterior capsulorhexis was compared with that of standard surgery. Anterior chamber depth (ACD) was assessed with partial coherence interferometry, measured before and after topical application of pilocarpine 2%, and near visual acuity (VA) was evaluated 3 months after surgery. MAIN OUTCOME MEASURE: Pilocarpine-induced change in ACD. RESULTS: The accommodating IOL showed a forward movement under pilocarpine with a median amplitude of movement of -314 microm (95% confidence interval [CI]: -148 to -592), compared with the backward movement of 63 microm (95% CI: 161 to -41) for the open-loop control IOL (P = 0.001). Capsule polishing and a posterior capsulorhexis had no effect on IOL movement with the accommodating IOL. The median near VA with distance correction was 20/60. CONCLUSION: Pilocarpine induced a small but significant forward movement of the accommodating IOL. However, the amount of movement was calculated to result in a refractive change of <0.5 diopters (D) in most patients, reaching 1 D or slightly more in only single cases, with a large variability of movement. Neither polishing of the capsule bag nor a posterior capsulorhexis could enhance the accommodative ability.

Accommodation, Ocular↗

Stimulus-driven versus pilocarpine-induced biometric changes in pseudophakic eyes.

PURPOSE: Most trials that study the lens movement of accommodative intraocular lens (IOLs) use pilocarpine to stimulate ciliary muscle contraction. The aim of this study is to assess in vivo whether a more physiologic, stimulus-driven accommodation is comparable to pilocarpine-induced IOL movement. DESIGN: Controlled patient- and examiner-masked clinical trial. PARTICIPANTS: The study population included 38 eyes with accommodative IOL implants (1CU) and a control group of 28 eyes with conventional open-loop IOLs. METHODS: A high-precision biometry technique, partial coherence interferometry, was used to measure IOL position. Anterior chamber depth was measured during physiologic (near point) and pharmacological (pilocarpine 2%) stimulation. In a subgroup of 14 1CU eyes, IOL position was determined repeatedly within 90 minutes after pilocarpine administration. A different subgroup was investigated as to the effect of cyclopentolate on IOL position. Best-corrected distance visual acuity (VA), best-corrected near VA, and distance-corrected near VA (DCNVA) were assessed using logarithm of the minimum angle of resolution charts. MAIN OUTCOME MEASURES: Anterior chamber depth change under pilocarpine and near-point-driven accommodation. RESULTS: Near-point accommodation did not induce movement of either the accommodating 1CU or the control IOLs. Pilocarpine induced a 201+/-0.137-mm anterior movement of the 1CU IOL (P<0.001), compared with no movement within the control IOL groups (P>0.05). There was no significant (P>0.05) difference in DCNVA between the accommodative and open-loop IOLs. No correlation between near point- or pilocarpine-stimulated IOL movement and DCNVA was found. Concerning the time course of movement after pilocarpine administration, most of the 1CU IOLs showed some movement 30 minutes after application. Cyclopentolate-induced ciliary muscle relaxation caused a posterior IOL movement, as compared with the relaxed state, when focusing on a distant target. CONCLUSION: Pilocarpine-induced ciliary muscle contraction seems to overestimate IOL movement relative to a monocular near-driven stimulus. Therefore, concerning IOL movement, pilocarpine may act as a superstimulus and may not adequately simulate daily life performance of accommodative IOLs. However, it may be helpful to evaluate the maximum potential of an accommodating IOL.

Accommodation, Ocular↗

Cataractous changes due to posterior chamber flattening with a posterior chamber phakic intraocular lens secondary to the administration of pilocarpine.

OBJECTIVE: To present the first reported case of cataract formation as a consequence of instillation of pilocarpine in an eye with a posterior chamber phakic intraocular lens (IOL). DESIGN: Interventional case report. INTERVENTION: A 46-year-old man received a hyperopic implantable collamer lens (ICL) bilaterally. MAIN OUTCOME MEASURES: Determination of best-corrected visual acuity (BCVA); contrast sensitivity testing with and without glare; and intraocular pressure (IOP), specular endothelial cell, and slit-lamp examinations were performed serially. In addition, the distance between the ICL and crystalline lens was measured with optical coherence tomography. RESULTS: Both eyes underwent uneventful ICL implantation for the correction of a manifest spherical equivalent of +7 diopters (D) in the right eye and +7.1 D in the left eye. The left eye was followed for 2 years without developing complications. The right eye, however, showed on the first postoperative day a fleckenlike opacification on the anterior pole of the crystalline lens after instillation on the operative day of 2% pilocarpine in an attempt to accelerate recovery from unwanted pupil dilation causing patient complaints of glare disability after surgery. Optical coherence tomography demonstrated complete contact of the ICL with the natural lens 24 hours postoperatively. Serial IOP measurements were always within the normal limits. The instillation of 1% cyclopentolate resulted in an increase in the ICL vault that measured 132 mum 24 hours later. Three days after the completion of a 3-day course of topical 1% cyclopentolate, the opacification was less dense and demarcated, and a 124-mum vault was measured. Three months postoperatively, the cataract was associated with a 3-line loss of BCVA and considerable degradation of the contrast sensitivity, especially at higher spatial frequencies and with a glare source, and corneal endothelial cell changes were within normal limits. One year after ICL implantation, the right eye had to undergo phacoemulsification and IOL implantation, which were uneventful. CONCLUSIONS: Posterior chamber flattening with resulting crystalline lens opacification can occur immediately after the instillation of pilocarpine in an eye with a hyperopic ICL. Therefore, caution should be taken with the administration of cholinergic agonists such as pilocarpine in patients with phakic IOLs, at least if they are hyperopic ICLs.

Cataract↗

Role of calcitonin gene-related peptide in the phenol-induced neurogenic hypertension in rats.

Previous investigations have demonstrated that capsaicin-sensitive sensory nerves are involved in the development of hypertension in some rat models of hypertension. To determine the role played by calcitonin gene-related peptide (CGRP; the predominant neurotransmitter in capsaicin-sensitive sensory nerves) in a rat model of neurogenic hypertension, in which hypertension was induced by injecting 50 microl of 10% phenol in the lower pole of the left kidney, systolic blood pressure (SBP) was monitored by the tail-cuff method throughout the experiment. Fifteen days after injection of phenol, mean arterial pressure (MAP), concentrations of CGRP in the plasma, the expression of CGRP mRNA in dorsal root ganglia (DRG) and CGRP content in laminae I and II of the spinal cord were measured. SBP was significantly increased 5 days after the intrarenal injection of phenol (164+/-7 mm Hg, p<0.01). At the end of experiment, blood pressure (BP) was significantly elevated in the phenol-injected rats compared with the controls (SBP: 187+/-6 vs. 122+/-4 mm Hg, p<0.01; MAP: 157.56+/-3.02 vs. 103.80+/-2.04 mm Hg, p<0.01). Treatment with capsaicin, which selectively depletes neurotransmitters from the capsaicin-sensitive nerves, failed to enhance the development of hypertensive responses to the intrarenal injection of phenol. Intravenous administration of CGRP(8-37), the specific CGRP receptor antagonist, also failed to increase the already elevated MAP. The expression of CGRP mRNA (both alpha- and beta-CGRP isoforms), the content of CGRP in laminae I and II of the dorsal horn of the spinal cord and the concentration of CGRP in the plasma was decreased in the rats treated with phenol. These results suggest that CGRP does not play a counterregulatory role in the phenol-induced hypertensive rats, and support the hypothesis that reduction of CGRP (alpha and beta isoforms) could contribute to a blood pressure elevation in this setting.

Animals↗

Exogenous and endogenous ghrelin in gastroprotection against stress-induced gastric damage.

Ghrelin, identified in the gastric mucosa has been involved in control of food intake and growth hormone (GH) release but little is known about its influence on gastric secretion and mucosal integrity. The effects of ghrelin on gastric secretion, plasma gastrin and gastric lesions induced in rats by 75% ethanol or 3.5 h of water immersion and restraint stress (WRS) were determined. Exogenous ghrelin (5, 10, 20, 40 and 80 microg/kg i.p.) increased gastric acid secretion and attenuated gastric lesions induced by ethanol and WRS and this was accompanied by the significant rise in plasma ghrelin level, gastric mucosal blood flow (GBF) and luminal NO concentrations. Ghrelin-induced protection was abolished by vagotomy and attenuated by suppression of COX, deactivation of afferent nerves with neurotoxic dose of capsaicin or CGRP(8-37) and by inhibition of NOS with L-NNA but not influenced by medullectomy and administration of 6-hydroxydopamine. We conclude that ghrelin exerts a potent protective action on the stomach of rats exposed to ethanol and WRS, and these effects depend upon vagal activity, sensory nerves and hyperemia mediated by NOS-NO and COX-PG systems.

Adrenergic Agents↗

[Current treatments of xerophthalmia in Sjögren's syndrome].

PURPOSE: To describe the large variety of treatments currently used in Sjögren's syndrome for one of its major manifestations, keratoconjunctivitis sicca or xerophthalmia. CURRENT KNOWLEDGE AND KEY POINTS: Sjögren's syndrome causes a diffuse immunoinflammatory disturbance of main lacrimal glands and the whole ocular surface. Dry eye syndrome is responsible for chronic and deep impairment of quality of life. Many different tear substitutes have been widely developed that are poorly efficient for relieving patients from their complaints. Tear substitutes of various viscosity from standard artificial tears to synthetic gels may be used. Hyaluronic acid is currently the most promising tear substitute, but all eye drops and gels are only efficient in mild to moderate dry eyes and keratoconjunctivitis sicca mostly resists to lubricants. Moreover, the latter may increase patients' complaints when they are associated to preservatives, antiseptic drugs that have widely demonstrated their toxic or irritating potential. Preservatives are, therefore, to be avoided whenever possible in keratoconjunctivitis sicca, by using monodose disposable packaging or specific bottle filtering or eliminating the preservative. Stimulation of lacrimal and salivary secretions with systemic pilocarpine, or obturation of lacrimal puncta in order to limit the drainage of tears in lachrymal ducts may be useful in most severe forms of Sjögren's syndrome. However, the development of topical cyclosporine and other immunomodulating agents is the most relevant progress in the treatment of keratoconjunctivitis sicca in Sjögren's syndrome. PERSPECTIVES: The future for treating Sjögren's syndrome is most likely to pass through the use of new drugs capable of treating the disease or at least its mechanisms, and not only to try to relieve symptoms with poorly efficient tear substitutes.

Administration, Topical↗

Changes in ocular torsion position produced by a single visual line rotating around the line of sight--visual "entrainment" of ocular torsion.

A large- or full-field visual stimulus slowly rotating around the naso-occipital axis of an observer causes both eyes to tort, and many of the factors controlling this optokinetic torsional response have been identified. The present study reports that a single line rotating about the line of sight can cause both eyes to tort in the same direction as the stimulus but with a low gain. We have used the term 'entrainment' to describe this torsional response. This paper reports some of the factors associated with entrainment. Video measures of 3-d eye position were recorded while the subject made settings of a simple visual line to subjective visual horizontal (SVH) and vertical (SVV) using the standard method-of-adjustment paradigm. The visual line was composed of 11 light-emitting diodes; the line subtended a visual angle of 19 degrees, and moved at a constant speed of 4.8 degrees /s. Settings were made in an otherwise darkened room, and also in the light. Subjects were required to maintain fixation of the central LED while making settings from starting positions 10 or 20 degrees either side of gravitational horizontal or vertical. We show that entrainment of ocular torsion by the single moving visual line is low in gain but a reliable and repeatable effect and that (1) there are considerable individual differences between subjects but within-subject consistency, (2) all subjects show larger and more consistent torsional entrainment for lines moving to SVH than lines moving to SVV, (3) the strongest entrainment generally occurs within about 10 degrees of the target position, and (4) entrainment is also present in the light, though with slightly reduced gain.

Adaptation, Ocular↗

Antiapoptotic effect of calcitonin gene-related peptide on oxidative stress-induced injury in H9c2 cardiomyocytes via the RAMP1/CRLR complex.

Calcitonin gene-related peptide (CGRP) plays an important role in the mediation of protective effects observed in situations such as ischemic preconditioning in rat hearts. In this study, we investigated in H9c2 rat cardiomyoblasts if the protective effect of CGRP could be linked to an inhibitory effect on the apoptotic pathway. We also determined the specificity of observed effects by treatment with adrenomedullin (ADM) in stress conditions generated by 100 microM hydrogen peroxide. Using MTT assays, we demonstrate that a pretreatment with CGRP decreases by half the loss of cell viability induced by H(2)O(2). CGRP inhibits phosphatidylserine externalization, caspase 3 activation and DNA fragmentation due to oxidative stress. Using RT-PCR, we observed an increase in Bcl-2 mRNA expression induced by CGRP treatment. Dot blotting experiments showed that, in stress conditions, Bcl-2 protein level decreases while Bax is increased. CGRP administration prior to stress prevents these effects. The three-receptor activity modifying protein (RAMP) isotypes were detected by RT-PCR in H9c2 cells and in left ventricle rat tissue, RAMP1 and RAMP3 being the most abundant in both cases. RAMP1 expression was upregulated by CGRP while RAMP3 mRNA level was decreased. Cell viability assessed by MTT indicates that, contrary to CGRP, pretreatment of stressed cells with ADM, a RAMP2 agonist, fails to protect them while treatment with CGRP(8-37) (a RAMP1 and 2 inhibitor) abolished CGRP protective effect. Taken together, these data suggest that CGRP has antiapoptotic properties through the RAMP1/CRLR complex. CGRP could be used to prevent apoptosis in an ischemia-reperfusion context.

Animals↗

Potential mechanism for the additivity of pilocarpine and latanoprost.

PURPOSE: To determine the ocular hypotensive mechanism underlying the additivity of latanoprost and pilocarpine. METHODS: This randomized, double-masked study included 30 patients with ocular hypertension on no ocular medications for at least 3 weeks. On each of six visits to the clinic, measurements were taken of aqueous flow and outflow facility by fluorophotometry, intraocular pressure by tonometry, and episcleral venous pressure by venomanometry. Uveoscleral outflow was calculated. Clinic visits were scheduled on baseline day; on day 8 of four times daily pilocarpine (2%) to one eye and vehicle to the other; on day 8 of continued pilocarpine/vehicle treatment plus latanoprost (0.005%) once daily to both eyes; after a 3-week washout period; on day 8 of once-daily latanoprost to one eye and vehicle to the other; and on day 8 of continued latanoprost/vehicle treatment plus pilocarpine four times a day to both eyes. Drug-treated eyes were compared with contralateral vehicle-treated eyes and with baseline day by paired t tests. Combined pilocarpine and latanoprost-treated eyes were compared with individual drug-treated eyes and with baseline day using the Bonferroni test. RESULTS: Compared with baseline, pilocarpine reduced intraocular pressure from 18.9 to 16.2 mm Hg (P =.001) and increased outflow facility from 0.18 to 0.23 microl per minute per mm Hg (P =.03). No other parameters were affected. Adding latanoprost further reduced intraocular pressure to 13.7 mm Hg (P <.001) and increased uveoscleral outflow from 0.82 to 1.36 microl per minute (P =.02). Latanoprost alone reduced intraocular pressure from 17.6 to 14.3 mm Hg (P <.0001) and increased uveoscleral outflow from 0.89 to 1.25 microl per minute (P =.05). Adding pilocarpine to the latanoprost treatment further reduced intraocular pressure to 12.7 mm Hg (P <.001) and increased outflow facility from 0.21 to 0.30 microl per minute per mm Hg (P =.03). CONCLUSIONS: Latanoprost and pilocarpine predominantly increase uveoscleral outflow and outflow facility, respectively, when given alone. These drugs are additive because pilocarpine does not inhibit the uveoscleral outflow increase induced by latanoprost.

Aged↗