S. Aschnu. Washington College.

In cases in which the atrial septum is absent purchase 100/60mg viagra with dapoxetine free shipping, distorted buy viagra with dapoxetine 100/60 mg low cost, or cannot be visualized cheap 100/60 mg viagra with dapoxetine free shipping, atrial morphology may be inferred by inspection of the free atrial wall. In contrast to a left atrium, a morphologic right atrium will have a large pyramidal appendage, a crista terminalis, and pectinate muscles (14). In situs ambiguus and other complex cases, the atrial septum can essentially be absent, resulting in a common atrium. In these cases, assignment of atrial “identity” can be challenging and often must rely on secondary, associated features. The presence of pectinate muscles and the crista is helpful in anatomic specimens. Anatomic determinants of the other cardiac segments also have been described and are summarized in Table 51. In these patients the appearance of both atrial appendages and the atrial free walls will have the characteristics of a right atrium. Even more rarely, in polysplenia syndrome with left atrial isomerism, both atrial appendages and free walls may resemble a left atrial appendage. The left atrial appendage usually has a narrow base and a tubular, hooked shape (Fig. However, in most cases with asplenia or polysplenia, the atrial anatomy is poorly defined, with a large common atrium, a thin rudimentary remnant of atrial septum, anomalies of systemic and pulmonary venous connections, and abnormal, but similarly shaped bilateral appendages. Pathologic specimen illustrating the anatomic features of the morphologic right and left atrial appendages with left juxtaposition. With incorporation of the sinus venosus, the coronary sinus also can be recognized as a reliable marker for the morphologic right atrium. This approach allows clinical assignment of atrial situs in most cases, although the most important clinical issues are often related to the position and spatial arrangement of the venoatrial connections rather than the morphologic identities of the atria themselves. The Lungs Pulmonary situs is determined by the sidedness of the morphologic right and left lungs. Clinically, this is defined by the relationship of the pulmonary arteries to their adjacent bronchi, and not by the number of lobes in each lung. In a morphologic right lung, the pulmonary artery travels anterior to the upper lobe and intermediate bronchi. In contrast, a morphologic left lung is characterized by a pulmonary artery that courses over the main bronchus and posterior to the upper lobe bronchus. The simplest method is by examination of the air bronchograms on a plain chest x-ray. In the setting of pulmonary isomerism (both lungs having the same morphology), however, the ratio approaches unity, because the lengths of the two main bronchi are similar. In these cases, bilateral trilobed (right) lungs should suggest the diagnosis of situs ambiguus with the asplenia syndrome (right isomerism), and bilateral bilobed (left) lungs the polysplenia syndrome (left isomerism). However, lung isomerism does not exist in all cases of cardiac isomerism and pulmonary isomerism can occur in patients without features of cardiac heterotaxia. Pathologic specimen (A) and drawing (B) illustrate normal tracheobronchial branching pattern as observed anteriorly. Note that the length of the left bronchus from the carina to its first branch is normally 1. This anatomic feature predicts pulmonary visceral situs based on measurements of the bronchial length. For example, atria and ventricles should be described both by their morphology and their right or left sidedness. In general, the position and orientation of the ventricular septum is used to describe the location of the ventricular chambers. Mesocardia is characterized by a vertical midline septum with side-by-side ventricles. Rarely, the ventricular septum is horizontal rather than vertical and results in superoinferior (over-and-under or “upstairs– downstairs”) ventricles. After the morphology and position of the cardiac segments are determined, the manner in which they connect to one another is evaluated. The difficulties encountered in the accurate definition of atrial situs based on atrial anatomy alone emphasize the importance of accurate determination of systemic and pulmonary venous connections, as described in Tables 51. This determination is particularly important for surgical management and should be a routine part of any imaging study. Although these basic combinations do not include all possible variations in ventricular and great artery spatial relationships, the important aspects of atrioventricular and ventricle–great artery connections are demonstrated. Ventricular Positions and Morphology Complete assessment of this segment includes an assessment of the cardiac base–apex axis to describe the three basic possibilities of levocardia, dextrocardia, or mesocardia as detailed previously. As covered elsewhere in this chapter, an evaluation of this segment should incorporate descriptions of the ventricular locations, relationships, function, and morphology, as well as the anatomy of the ventricular septum and any septal defects. Great Artery Relations The great arterial connections, the spatial relationships between the arteries and their subsequent distribution/branching patterns, must be determined as described in Table 51. Eight basic types of great artery relationship are possible based on the aortic and pulmonary valve positions at the level of the semilunar valves. Directly posterior aorta This type of segmental approach to complex cardiovascular malformations allows prediction of all possible cardiac conditions that could be encountered. Its flexibility depends upon the sequential addition of each cardiac segment and relevant connections, accounting for all possible combinations of atrial, ventricular, and great arterial anomalies. Cardiac Imaging: Use of the Segmental Approach Transthoracic echocardiography is a convenient and noninvasive technique that can provide most of the clinically relevant information concerning the cardiovascular anatomy and physiology, especially in young patients. We will primarily use echocardiographic examples to illustrate the segmental approach, but the concepts are applicable to, and should be used in all tomographic imaging modalities. The imaging approach to patients with cardiac malpositions should follow the same sequential segmental pattern used by the anatomist/pathologist as outlined earlier in this chapter and in many reports (20,21,22,23). The following section and accompanying images of normal and malpositioned hearts are included to illustrate the tomographic and three-dimensional anatomy associated with these malformations and to assist the reader in correlating the imaging findings with anatomic examples of these complex hearts. As previously described, situs ambiguus has been used to describe a wide spectrum of anomalies, including the visceral P. The visceral situs is considered “ambiguous,” because it does not conform to the classical patterns of situs solitus or inversus. Nearly all possible combinations of abdominal organ and great vessel location have been reported (19,22). The term visceral situs ambiguus does not mean that the positions of the abdominal organs cannot be determined. Their positions and venous connections can and must be accurately defined before corrective surgical procedures can be performed. A: The subcostal short-axis scan of the abdomen demonstrates an initial right-to-left orientation for visceral situs determination.

In lesser degrees of obstruction surgery can be done semielectively order 100/60 mg viagra with dapoxetine free shipping; diuretics are often effective at reducing pulmonary edema buy cheap viagra with dapoxetine line. Surgical approach varies best order for viagra with dapoxetine, with some centers preferring a median sternotomy, others a right thoracotomy. However, a shunt via innominate artery often can provide excessive pulmonary blood flow; the placement of a shunt from the smaller right subclavian artery via thoracotomy will limit blood flow. These details must be communicated during the surgical handoff, and the patient managed accordingly. Excessive pulmonary blood flow is heralded by high oxygen saturations even on low FiO , and low diastolic blood pressures; coronary ischemia and cardiovascular collapse is possible. This is2 managed with manipulation of the FiO and ventilation, and with inotropic and vasopressor support to increase2 the systolic and diastolic blood pressure. The problem of excessive pulmonary blood flow is especially prevalent in small neonates under 2. Maintaining systolic blood pressure at 70 mm Hg or higher is desirable early in the postoperative course, to promote pulmonary blood flow. Low- dose heparin infusion is instituted in the first 6 to 12 hours postoperatively. Conversely, severe hypoxemia may be caused by mechanical obstruction of the shunt, pulmonary hypertension, or systemic hypotension leading to decreased pulmonary blood flow. This situation must be investigated emergently by echocardiography; maintaining high systolic blood pressure is crucial if shunt narrowing by thrombosis is suspected. Emergent revision of the shunt may be needed surgically; alternatively it is sometimes possible to dilate the shunt in the catheterization laboratory. Prevention of shunt thrombosis with low-dose heparin, and adequate systolic blood pressure and prevention of pulmonary hypertension is a key point. Branch pulmonary arteries are repaired by pericardial or homograft patch if needed. A coronary artery branch from the left anterior descending coronary artery may be present near the site of right ventriculotomy, and coronary ischemia is possible if this structure is injured or distorted by the surgery. This is an important piece of information that must be communicated during handoff from the surgical team, as this will often explain arterial desaturation in the early postoperative period. Blood pressure monitoring with an arterial catheter in the right upper extremity is necessary. Most neonates will tolerate this surgery well, with minimal requirement for inotropic support and are able to wean from mechanical ventilation in 24 to 48 hours after surgery. Older children will often be extubated in the operating room, and require vasodilators early postoperatively for blood pressure control. Because of the rare complication of paraplegia due to spinal cord ischemia from clamping above the level of the artery of Adamkovich at about the T9 level, all patients should be assessed for lower extremity movement as soon as possible after surgery. These patients are at significant bleeding risk postoperatively due to extensive aortic suture lines, and adequate blood products must be available for hemostasis early in the postoperative course. The early phase is catecholamine-mediated and usually best treated with β-blocking agents such as esmolol or labetalol. The pulmonary arteries are sometimes patch augmented, and any intracardiac issues, that is, significant atrioventricular valve regurgitation, or atrial septectomy, addressed. Analgesics such as morphine, acetaminophen, ibuprofen, and ketorolac are effective; the adjustment of the cerebral circulation is accompanied by diminution of these symptoms, usually after 48 to 72 hours. The relatively large brain of the young infant carries a large percentage of the cardiac output. This in turn decreases superior vena cava flow, decreasing pulmonary artery flow, which will lead to decreased systemic arterial oxygenation. Fontan Completion Total cavopulmonary connection is the intended final stage of palliation for most single-ventricle patients. The surgical procedure itself has undergone many modifications since its original description by Fontan and Baudet in 1971 (Fig. A fenestration is sometimes created from the Fontan circuit to the left atrium, which is a 3- to 5-mm communication allowing a right to left shunt, which lowers Fontan circuit pressure and allows greater systemic cardiac output at the expense of some arterial desaturation (286). It should be noted that many Fontan completions, even without fenestration, are not fully saturated due to the position of the coronary sinus in the left atrium. Because the total cavopulmonary connection results in the absence of a pulmonary ventricle to actively pump blood into the lungs, flow in this circuit depends in large part on negative intrathoracic pressure creating a gradient from the extrathoracic systemic venous return to the cavae and heart. Therefore, positive pressure ventilation will decrease venous return and cardiac output. Many centers will extubate the Fontan patient in the operating room and limit the dose of opioids to promote venous return and maintain cardiac output. The Fontan patient is highly dependent on adequate filling volume in the total cavopulmonary connection in the early postoperative period to maintain cardiac output. In the ventilated patient, the effect of the positive pressure can be overcome with higher filling pressures, that is, 15 to 20 mm Hg. A key point in the early postoperative period is not to get behind in volume replacement; bleeding from repeat sternotomy and large pleural and mediastinal tube output from increased right-sided pressures often result in significant need for volume replacement. Inotropic support in the form of milrinone, and low-dose epinephrine or dopamine is often needed in the early postoperative course. Nonfenestrated patients especially are prone to high Fontan pressures and pleural effusions; conversely, they will benefit the most from early extubation. Differential diagnosis of abnormal post-Fontan hemodynamic states is presented in Table 24. Other Left-Sided Obstructive Lesions Aortic stenosis, mitral stenosis, and Shone complex patients present with a myriad of anatomic variations; the preoperative status of the patient, including ventricular dysfunction and/or hypertrophy, and any medications including β-blockade, must be reviewed. Details of the surgery, whether valve repair with subaortic resection, or valve replacement, must be communicated. With normal or hyperdynamic left ventricular function preoperatively, relief of mechanical obstruction will often result in a hypertensive patient and β-blockade with esmolol should be considered, along with other vasodilator therapy, that is, nitroprusside or calcium channel blocker such as nicardipine in older patients. It is important to control blood pressure, as there will frequently be a long aortic suture line and bleeding or dehiscence can accompany uncontrolled elevated blood pressure. Patients with poor ventricular function may require significant inotropic support. Other important considerations are the status of the coronary arteries, and whether there is proximal coronary artery atresia and right ventricular–dependent coronary sinusoids. Cardiac Transplantation The preoperative status of the transplantation patient must be thoroughly reviewed and understood, particularly in reference to pulmonary hypertension, which can complicate the postoperative course. Generally speaking, ischemic times less than 5 hours are desirable, with better myocardial function in the early postoperative period. It is also important to understand if the patient has elevated panel reactive antibodies, or a positive cross match with the donor heart. In such cases, intraoperative or postoperative plasmapheresis may be instituted to minimize risk of early rejection.

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Therefore cheap viagra with dapoxetine generic, pharmacologic therapy can be used to delay surgical treatment in affected children but the need for close follow- up is fundamental safe 100/60mg viagra with dapoxetine. Avoidance of maximal and isometric exertion is also recommended purchase viagra with dapoxetine overnight delivery, although exercise restrictions may not always be applicable in younger children. A valved conduit is sutured to the aortic annulus and the coronary arteries are reimplanted into the graft. A tubular Dacron graft is used with the proximal end tailored to reconstruct the aortic sinuses. The aortic sinuses are excised leaving a trim of aortic tissue attached to the aortic annulus and around the coronary artery orifices. The aortic valve is reimplanted inside a tubular Dacron graft using two suture lines, one below and one above the aortic annulus. The coronary arteries are reimplanted into their respective aortic sinuses and the graft is anastomosed to the distal ascending aorta (52). If the aortic valve is affected, a composite replacement of the valve and ascending aorta is performed. In cases with no substantial aortic valve disease, valve-sparing techniques can be applied, including remodeling of the aortic root or reimplantation of the aortic valve (Fig. Nonetheless, there is a lack of similar data in children owing to the rarity of aortic complications in this age group. Due to the absence of general consensus in the pediatric population, most centers advise prophylactic surgery using the diameter criterion for adults (∼50 mm) but also take into consideration the presence of accelerated aortic growth (>10 mm/yr), development of aortic regurgitation, or need for mitral valve surgery (37). Following aortic root surgery, close follow-up and continuation of medical therapy is necessary, since distal segments of the aorta may also be affected (40). This can be positioned around the aortic root and ascending aorta without cardiopulmonary bypass and involves a shorter operation, than that for the conventional approach. After putting together a research and development team, and finding a surgeon to take on the challenge to join him in this innovative approach, he was central to the manufacture of the device, custom made for his own aorta. Ten years later he is well; subsequently 45 other people have had their own personalized devices implanted. This procedure could be an alternative surgical route for teenagers/older children, although more data are clearly required. In some instances, the pattern of inheritance is autosomal dominant with variable penetrance and a male/female ratio of 3:1 (56,57). Development of a bileaflet aortic valve predisposes to several complications, including valvular dysfunction and infective endocarditis (58,59,60,61). A shows normal distribution of the elastic lamellae (purple), and B shows severe medial wall degeneration with elastic fiber fragmentation and accumulation of basophilic ground substance (pink). In vitro experiments have shown that cultured human endothelial cells respond to different levels of wall shear stress (69). Therefore, the traditional threshold of 50 mm for aortic repair is used along with aortic growth rate exceeding 10 mm/yr, and need for aortic valve surgery with an aortic diameter of more than 45 mm (81). Valve- sparing procedures are favorable in children with an aortic annulus greater than 18 mm. The presence of a bileaflet aortic valve is not necessarily a contraindication to a valve-sparing operation unless there is significant valve regurgitation, leaflet distortion, or calcification (81). Use of a composite valve graft is preferable in cases of acute aortic dissection and abnormal aortic valve leaflets. Homografts can be used as an alternative in children with an annulus of less than 18 mm. However, their durability is limited leading to a reoperation rate of approximately 40% in several pediatric series 50,82–84). Despite the satisfactory results of the procedure, durability limitations have been reported by the end of the first postoperative decade in younger patients (85). Predictors of autograft failure in children include the presence of preoperative aortic regurgitation and aortic root dilation (85). Approximately 7% of affected individuals have a deletion on chromosome 22q11 with important implications in terms of genetic counseling and family screening, due to the associated 50% risk of transmission (88). Excessive development of aortic enlargement is one of the contributing factors to late morbidity in this patient cohort (92). Aortic root dilation may lead to aortic regurgitation due to incomplete leaflet coaptation, necessitating aortic valve replacement (93). It remains unknown whether hemodynamic stress, even present before birth, is the causal mechanism for the structural changes in the aorta. A different study reported similar findings with increased diameters in the first 3 to 6 months after palliative shunt surgery (97). In case of progressive dilatation, imaging of the aorta is recommended on an annual basis (Fig. Despite the increased recognition of aortic pathology in this patient cohort, aortic dissection has only been reported in a few isolated cases with an aortic diameter of ≥55 mm with additional risk factors (8,9,10). Aneurysm formation is a known clinical feature of the disease and may occur at the site of previous surgical repair or in the proximal aorta (101). Natural history studies report dissection of the aorta as the cause of death in 19% of patients with coarctation, reaching 50% in the presence of a concomitant bileaflet aortic valve (102). The disease is associated with significant cardiovascular morbidity, even following surgical repair, with survival rates of 72% at 30 years (103). The commonest cause of late death is coronary artery disease followed by sudden death, heart failure, cerebrovascular accidents, and ruptured aortic aneurysm (103). Structural abnormalities of the aortic media in coarctation patients have been reported within 24 hours after birth, implying an intrinsic underlying cause (104). Moreover, medial wall abnormalities were identical at sites subjected to high and low pressure (proximal and distal ends of the coarctation site), eliminating the influence of hemodynamics in the described pathology (16). Cardiac structures derived from neural crest cells include the outflow tract of the heart and the aortic arch system, as well as the cervicocephalic arteries. Development of aneurysm at the site of surgical repair is associated with the patch graft technique and repair of coarctation before the age of 14 years (11). Imaging follow-up of both the ascending and descending thoracic aorta is recommended in coarctation patients, irrespective of previous repair, for early detection of aortic wall complications (101,107). Prophylactic treatment with β-blockade as well as appropriate timing of surgical intervention on the dilated ascending aorta in this patient cohort remains uncertain. Nonetheless, the cumulative incidence of grade 2 or higher regurgitation was 9% at 15 years, with pulmonary outflow obstruction reported as the main cause for reoperation. Interestingly, aortic root pathology has also been described in this lesion following the Mustard procedure, but may be largely underestimated due to other serious complications of the technique, such as right ventricular dysfunction, arrhythmias, and sudden cardiac death (1). Importantly, in the majority of patients with neoaortic dilation, a stabilization of Z-scores was observed during late follow-up, suggestive of absence of progressive dilation.

The remaining bony clivus was removed with exposure of the clival dura with a central defcit through which the chordoma entered the pos- terior cranial fossa discount viagra with dapoxetine 100/60 mg on line. Utilizing the two-surgeon approach the intracranial portion of the tumor was slowly mobilized under direct vision buy viagra with dapoxetine 100/60mg without a prescription. A 30-degree endoscope was used to visualize the inferior intracranial extension of the tumor order 100/60 mg viagra with dapoxetine fast delivery. Note the signifcant posterior indentation of the displaces the basilar artery (black arrow) laterally. This repair remains intact after 4 years follow-up showed a lesion extending from internal carotid to internal 252 Endoscopic Sinus Surgery Fig. Once dura was exposed inferiorly anterior surface of the pons and displaces the basilar artery (at the base of the clivus), laterally (behind the carotids), and laterally (Fig. The tumor was placed under slight trac- sible inferior bony extension of these tumors. There is signifcant bony erosion of this sphenoid/clival component of the tumor was divided from part of the clivus down toward the foramen magnum. In this the intracranial extension at the level of the posterior fossa patient more bony erosion is seen on the right side (white dura. The dural dard pituitary exposure with wide sphenoidotomies, septal defect was enlarged with the endoscopic skull base scissors resection, and foor of sphenoid resection. The endoscope was switched to a 30-degree endoscope and This delineates the superior and lateral margins of the dissec- the posterior cranial fossa reexplored. Next the foor of the sphenoid was drilled away and the seen superiorly on the anterior face of the pons. A suction tumor followed laterally behind the vertical portions of the regulator was placed in the suction line limiting the amount 19 Endoscopic Resection of Clival and Posterior Cranial Fossa Tumors 253 of suction and the malleable frontal sinus suction was bent Conclusion so it could be placed through the dural defect superiorly and the residual tumor indenting the pons was gently removed. Endoscopic resection of clival and posterior cranial fossa Complete macroscopic tumor resection was achieved. Fibrin glue and a nasal pack were put in endoscopic skull base team, normally consisting of a rhi- place. Four of the six primary cases had radiotherapy with one patient having proton beam irradiation. Skull base chordomas: tumor resection was possible and in this group there has been overview of disease, management options, and outcome. Neurosurg no recurrence of tumor since resection with a mean follow- Focus 2001;10(3):E12 up of 3. Transmandibular,circumglossal, retropharyngeal approach for chordomas of the clivus and upper cervi- tumor is growing very slowly and this is being monitored cal spine. Laryngoscope 2005;115(11):1917–1922 seven revision cases, all had their primary surgery at other 5. Five still have radiological residual disease with transnasal transphenoidal approach for the treatment of cranial base chor- two patients deceased. Op Neurosurg Suppl 2006;1:50–57 Endoscopic Resection of Anterior 20 Cranial Fossa Tumors Endoscopic techniques for transnasal resection of anterior endoscopically. Although the gold standard for resection cranial fossa tumors were developed for tumors involving the of these malignancies was a craniofacial resection,1 there nasal cavity, sinuses, and the anterior cranial fossa. However, is increasing evidence that for selected patients the wholly experience with these tumors has led to the refnement of endoscopic resection yields comparable results. The frst step toward a wholly endoscopic resection of incisions with improved cosmetic results. We found undergo this procedure, can be ofered the endoscopic ap- that the endoscopic resection of the sinonasal component proach as an alternative. Endoscopic resection of the ante- could be as efectively dealt with endoscopically as it can with rior skull base requires a detailed knowledge of the anatomy external traditional approaches. A signifcant number of these malignant tumors Anatomy of the Anterior Skull Base attach to the skull base and associated orbit. During cranio- facial resection the skull base involved with tumor is com- The anterior skull base consists of the orbital plates of the pletely excised. These plates attach to the planum We found that endoscopically resecting the sinonasal com- sphenoidale (lesser wing of the sphenoid bone) posteriorly ponent aforded better visualization of the tumor allowing (Fig. The cribriform plate gives rise to the crista galli the nonattached tumor to be extensively debulked and the onto which the falx cerebri attaches anteriorly. This If the anterior skull base is approached endoscopically in turn allowed a complete resection of the sinonasal and, if from front to back the frontal bone (posterior wall of the present, the orbital component. Posteriorly tions developed, these techniques could in turn be applied the foveae ethmoidalis and cribriform plates attach to the to the resection of malignant tumors involving the skull base planum sphenoidale (Fig. Tumors thought to be suitable were structures within the anterior skull base are the anterior and tumors with a localized intracranial extension. Note how there is a space or cell infltrative nature of squamous cell carcinomas these were between the frontal sinus ostium and the anterior ethmoidal thought not to be as suitable as adenocarcinoma and esthe- artery (Fig. This is always the case as the artery usually sioneuroblastoma, which in general have a pushing rather runs in the base of the second lamella which is the upward than infltrative front and are thus more easily addressed continuation of the anterior face of the bulla ethmoidalis. One of the frst decisions that need to be made is whether the entire skull base needs to be resected. If the tumor approaches but does not come further for- ward than the anterior ethmoidal artery then the posterior skull base can be resected without the need to perform a modifed Lothrop or frontal drillout procedure. This is necessary so that, once the inside of the tumor has been debulked, the tumor arachnoid plane can be identifed and the tumor wall collapsed into the tumor cavity allowing progressive resection of the tumor. Resection of the skull base is only possible once the en- tire skull base has been exposed. This requires, as a frst step, bilateral sphenoethmoidectomy with exposure of the skull base within the sphenoids, anterior and posterior ethmoids, and visualization of the frontal ostia. If the en- tire anterior skull base is to be resected the frontal sinuses need to be drilled out with an endoscopic modifed Lothrop procedure. The relationship between the cribriform plate and the frontal sinuses is clearly illustrated in this oste- ology model and illustrates the importance of performing a frontal drillout procedure for more anteriorly based tu- mors (Fig. The other important structures that need to be identifed are the anterior ethmoidal artery and the posterior ethmoidal artery. Note how the anterior eth- moidal artery has the anterior ethmoidal nerve running Fig. Our preferred technique is to expose the ar- they push posteriorly and superiorly (Fig. However, if the burr is too big or if and then form the anterior portion of the circle of Willis and the exposure is done over the lateral area on the triangular go on to supply the anterior cranial fossa. The most common fat invagination, division of the artery with the burr may tumor in this region is the tuberculum sella meningioma but result in retraction of the artery into the orbit and orbital others include craniopharyngiomas and anterior/superior hematoma formation. When the tumor flls the sub- which an anterior skull base tumor was being removed chiasmatic cistern, the superior hypophyseal vessels are also and required an immediate orbital decompression to re- at risk and damage to these vessels can lead to ischemic dam- lieve the pressure in the eye.