Anterior Segment Ischemia Research Articles

Myopexy of the vertical rectus muscles using expanded polytetrafluoroethylene for management of a lost medial rectus muscle

Strabismus due to a lost rectus muscle is uncommon. Surgical treatment of the condition by means of scleral augmented myopexy of the vertical rectus muscles can reduce the potential for anterior segment ischemia by leaving the vascular supply intact. We report a successful use of expanded polytetrafluoroethylene in this procedure to correct long-term exotropia caused by a lost medial rectus muscle.

Ocular Ischemia and Ischemic Oculomotor Nerve Palsy After Vascular Embolization of Injectable Calcium Hydroxylapatite Filler

A healthy 25-year-old man who received a calcium hydroxylapatite filler injection for nose augmentation by a dermatologist suddenly developed blepharoptosis and orbital pain on the right side, associated with progressive visual disturbance of the right eye. Patchy necrosis at the nose and glabella, limitations of extraocular movements, and anterior segment ischemia, as evidenced by conjunctival injection, chemosis, corneal edema, dilated pupil, hyphema, and hypopyon, were noted. Orbital CT demonstrated linear deposits of a similar density to bone in the right medial orbit and eyelid, suggestive of multiple emboli along the conjunctival vessels. A provisional diagnosis of ocular ischemia and ischemic oculomotor nerve palsy secondary to vascular embolization was made. After 3 months, visual acuity, all intraocular inflammation, oculomotor nerve palsy, and skin necrosis resolved completely except for a dilated pupil.

A New Muscle Transposition Procedure to Correct Cyclodeviation Without Tenotomy

The authors developed a new surgical procedure for use in treating pure cyclodeviation. This procedure was accomplished by a simple muscle transposition technique without tenotomy. Satisfactory postoperative results were achieved without postoperative complications. This procedure may be useful for treating cyclodeviations, with minimal risk of surgical complications, particularly anterior segment ischemia.

Reply re: "Anterior Segment Ischemia and Retinochoroidal Vascular Occlusion After Intralesional Steroid Injection".

A 19-year-old woman was admitted with sudden severe pain and loss of light perception that began immediately after eyelid injection of the depot form of corticosteroid. Ecchymosis of the lower eyelid, corneal edema, and a fixed dilated pupil were noted. Fundus examination could not be performed because of corneal edema. Embolic material packed in the episcleral vessels was detected. With these findings, the diagnosis was anterior and posterior segment ischemia. Despite administration of an intravenous hyperosmotic agent, in addition to topical and systemic pulse corticosteroid (1.0 g/day), vision was not recovered. The most serious complication of intralesional injection of corticosteroid is vascular occlusion. This catastrophic complication after intralesional steroid injection should prompt immediate ophthalmoscopic fundus examination to allow early recognition of ischemic signs and immediate intervention.

Resolution of anterior segment ischemia after the removal of lateral fixation sutures

Anterior segment ischemia is a rare but well-recognized complication after strabismus surgery, involving multiple extraocular muscles. We report a case of traumatic left sixth nerve palsy in a 32-year-old man who developed anterior segment ischemia after left medial rectus muscle recession and partial tendon transfer of the vertical rectus muscles to the lateral rectus, augmented by lateral fixation sutures. The corneal edema and anterior chamber reaction cleared upon removal of the lateral fixation sutures and institution of steroids and cycloplegics. The possible role of lateral fixation sutures in anterior segment ischemia is discussed.

Surgical Repair of Cyclodialysis Cleft

Cyclodialysis cleft is separation of meridonal ciliary muscle fibers from the scleral spur, thereby creating an additional drainage pathway of aqueous humor into the suprachoroidal space.1-4 This new drainage pathway leads to increase in uveoscleral outflow and may result in chronic ocular hypotony.5 The hypotony may also be due to decreased aqueous production.6 In past, creating an iatrogenic cyclodialysis cleft was used as one of the surgical option for the management of aphakic glaucoma. Cyclodialysis mostly occurs inadvertently during anterior segment surgery or due to blunt ocular trauma.2,7 The magnitude of the hypotony due to cyclodialysis cleft may not be proportional to the size of the cleft.5 As a result of ocular hypotony, patient may develop choroidal effusion, cystoid macular edema, optic nerve edema, engorgement and stasis of retinal veins, retinal folds, shallow anterior chamber, and cataract. Cystoid macular edema is one of the major contributing factor for visual loss due to hypotony caused by cyclodialysis cleft. If hypotony remains undetected and untreated for long time, visual loss may become permanent. Ocular hypotony itself is the most frequent cause of ciliochoroidal detachment following cataract extraction. Therefore, prior to considering cyclodialysis cleft as a cause of hypotony, other causes like wound leak, retinal detachment, chronic inflammation, and anterior segment ischemia should be ruled out. A careful gonioscopic examination of the anterior chamber angle is the key to the diagnosis of iatrogenic or traumatic cyclodialysis cleft. Sometimes it is difficult to see the cleft itself, as it is often small and obscured by a narrowed anterior chamber angle. A shallow chamber generally is caused by diffuse choroidal effusion due to hypotony that leads to forward displacement of the lens iris diaphragm. It has been suggested that anterior chamber deepening by the injection of a viscoelastic agent into the anterior chamber may facilitate visualization of the cleft.8 High-resolution ultrasound biomicroscopy (UBM) is a good tool to diagnose and provide detailed information about the extent and location of a cyclodialysis cleft.9-11 UBM allows imaging of a cyclodialysis cleft along its entire longitudinal and circumferential extent, with an accurate assessment of its location and size, regardless of gonioscopic visibility or patent cleft aperture.10,11 While gonioscopy allows evaluation only from the anterior face of the ciliary cleft, UBM provides cross sectional information of the iridocorneal angle. Once the diagnosis of cyclodialysis is made, medical treatment consisting of topical 1% atropine, 2 to 3 times daily should be attempted at-least for 6-8 weeks. Miotics and corticosteroids should be avoided. If the cleft is small in size (< 1⁄2 clock hour) or no significant structural or functional abnormalities secondary to hypotony is seen, then, wait and watch along with medical treatment may be the best mode of action. In small clefts, Argon laser therapy for repair of cyclodialysis can be tried. Various treatment options to close the cleft with laser has been described.3,12-17 It is assumed that, following laser treatment, edema of the choroid closes the cleft and blocks aqueous flow into the suprachoroidal space or perhaps the inflammation produced by laser treatment plays a role in altering the aqueous humor composition, thereby obstructing the drainage.13 Other surgical options includes external transconjunctival cryotherapy at the presumed location of a cyclodialysis cleft, direct cyclopexy, ciliochoroidal diathermy, anterior scleral buckling, or vitreoretinal procedures.18-24 We usually reserve surgical intervention for those cases that do not respond to medical treatment. We prefer direct surgical cyclopexy (Cleft closure) to other surgical options.

Chandler syndrome manifesting as ectropion uvea following laser in situ keratomileusis

We report the case of a 30-year-old woman with recent onset of unilateral iris distortion and glaucoma that was noticed following uneventful laser in situ keratomileusis (LASIK). The corneal endothelium in the right eye appeared normal with the slitlamp microscope, and LASIK-related anterior segment ischemia was initially considered in the differential diagnosis. However, in vivo confocal microscopy revealed abnormal endothelial cells, confirming the diagnosis of iridocorneal endothelial syndrome. In patients having refractive corneal procedures, in vivo confocal microscopy is recommended to diagnose preexisting corneal abnormalities that might otherwise remain undetected.

ANTERIOR SEGMENT ISCHEMIA FOLLOWING LASER THERAPY FOR THRESHOLD RETINOPATHY OF PREMATURITY

To report on the clinical characteristics and outcomes of premature infants developing signs of anterior segment ischemia after laser therapy for threshold retinopathy of prematurity treated or referred to a university institution. A retrospective review of the medical records of premature infants with a primary diagnosis of retinopathy of prematurity undergoing laser therapy for threshold disease from January 1, 2001, to June 1, 2006. A total of 10 eyes in six patients were identified that developed signs of anterior segment ischemia for which a 1-year follow-up was available. The mean gestational age of patients developing anterior segment ischemia was 26.1 weeks. The mean weight was 855 g. The mean gestational age when laser photoablation was initiated was 36.3 weeks. All infants developing ischemia were treated with intermittent dense laser pattern using the diode laser. No infants treated thus far with confluent laser pattern have developed anterior segment ischemia. Confluent laser pattern in our experience does not predispose to anterior segment ischemia. Anterior segment ischemia primarily affects premature infants less than 28 weeks gestational age with low birthweights, less than 1,075 g. Intravitreal steroids at the time of pars plana vitrectomy and lensectomy may be beneficial in selected patients.

Anterior Segment Ischemia After Two-Muscle Surgery in a Patient With Radiation-Treated Nasopharyngeal Carcinoma

Anterior segment ischemia after strabismus surgery is a rare occurrence. Risk factors include single-stage surgery of three or more muscles in one eye, dysthyroid eye disease, and advanced age. The authors report a case of anterior segment ischemia after single-stage surgery of two horizontal muscles without previous reported risk factors. However, the patient had received radiotherapy for nasopharyngeal carcinoma more than 20 years ago. The case was successfully treated with systemic steroids but with reduced best-corrected visual acuity. Previous radiotherapy in the related orbital field may be a new risk factor for this condition.

Anterior Segment Ischemia and Retinochoroidal Vascular Occlusion After Intralesional Steroid Injection

A 19-year-old woman was admitted with sudden severe pain and loss of light perception that began immediately after eyelid injection of the depot form of corticosteroid. Ecchymosis of the lower eyelid, corneal edema, and a fixed dilated pupil were noted. Fundus examination could not be performed because of corneal edema. Embolic material packed in the episcleral vessels was detected. With these findings, the diagnosis was anterior and posterior segment ischemia. Despite administration of an intravenous hyperosmotic agent, in addition to topical and systemic pulse corticosteroid (1.0 g/day), vision was not recovered. The most serious complication of intralesional injection of corticosteroid is vascular occlusion. This catastrophic complication after intralesional steroid injection should prompt immediate ophthalmoscopic fundus examination to allow early recognition of ischemic signs and immediate intervention.

Anterior segment ischemia in a young myopic following transposition surgery

A 35-year-old Kuwaiti lady, who is a known myope, developed severe anterior segment ischemia following extra-ocular muscle transposition surgery. The patient was treated with topical and systemic steroids. Her best corrected visual acuity after complete resolution of the inflammation was 20/40. She also developed pupillary mydriasis and anterior lens changes.

Superior oblique anterior tenectomy

To describe a surgical approach to selectively weaken the anterior cyclotorsional fibers of the superior oblique muscle in subjects with incyclotorsion. Retrospective review of five consecutive subjects with diplopia and incyclotorsion who underwent unilateral tenectomy of the anterior fibers of the superior oblique alone or in combination with surgery on another horizontal or vertical rectus muscle. The mean preoperative incyclotorsion was 7.2 degrees . The mean postoperative follow-up was 4 months. Superior oblique anterior tenectomy corrected 5.2 degrees of incyclotorsion. No patient developed pattern strabismus induced vertical deviation or diplopia due to excyclotorsion postoperatively. The mean incyclotorsion present at the last follow-up was 2 degrees . Torsional diplopia persisted in two (40%) subjects. Anterior tenectomy of the superior oblique tendon at the insertion may be helpful in subjects with incyclotorsion who have no vertical deviation in the primary position or in whom there is risk of pattern anisotropia or anterior segment ischemia by operating upon vertical rectus muscles.

Neovascular membrane over the ciliary body as a potential complication of transscleral diode laser cyclophotocoagulation

Neovascular membrane over the ciliary body as a potential complication of transscleral diode laser cyclophotocoagulation

Traumatic tear of the inferior rectus muscle treated with inferior oblique anterior transposition

To report a case of traumatic tear of the inferior rectus muscle treated with inferior oblique anterior transposition (IOAT). Case report of a 55-year-old man who presented with vertical diplopia (VD) after orbital trauma. Ocular examination disclosed a 62PD right hypertropia (RHT) in the primary position (PPO). The right inferior rectus (RIR) was torn, and the distal stump was fixed to the skin with tape. Surgery was performed under local anesthesia. The RIR tearing occurred 13 mm from the insertion, and exploration revealed its proximal end. The right inferior oblique (RIO) was intact, although its fibers were loose. Since the RHT did not improve following reattachment of the proximal and distal stumps of the RIR, the distal stump was excised and the proximal end brought forward and sutured 6.5 mm from the limbus. At perioperative evaluation, there was a 25PD RHT in PPO where the VD persisted. The RIO was subsequently isolated, detached, and its distal end, after 6 mm resection, was sutured to a point temporal to the lateral border of the RIR. The patient was reevaluated and had neither RHT nor VD in primary gaze. At the 6-week postoperative evaluation, he was orthotropic in PPO, complaining about diplopia only on extreme downgaze. A mild limitation of right depression was observed. The patient was satisfied with the surgical results and experienced no functional limitations during any activities. IOAT can provide acceptable binocular visual function without the risk of anterior segment ischemia in cases of torn inferior rectus muscle.

Authors′ reply

Dear Editor, We thank Azad et al. for showing interest in our article.1 As this child needed immediate intervention to save the eye and prevent phthisis bulbi, a formal institutional review board approval was not possible as it would have taken at least a few months. The principal concern was potential altered vasculogenesis in the treated eye and other organs. But as the avascular retina was well ablated, we believe it safer to inject bevacizumab (Avastin) in this situation rather than as primary therapy in an eye with viable peripheral retina. With this background in the face of an eye that was rapidly deteriorating to cyclitic membrane formation and phthisis the authors considered the potential benefits and harmful side effects of intravitreal bevacizumab. The parents received extensive councelling regarding potential complications of bevacizumab including possible retarded growth or maldevelopment of other organs Aggressive posterior retinopathy of prematurity (ROP) is now a distinct category of ROP which has been published2 and does not need further elaboration. The disease was symmetrical in both the eyes. There was no tunica vasculosa lentis seen prior to laser and iris neovascularization, hypotony, cataract and corneal clouding appeared after the ablative procedure. Given these features, anterior segment ischemia was the most likely diagnosis. Without prompt intervention, the eye would have likely progressed quickly to irreversible phthisis. Ocular hypotony due to scleral indentation is a consideration but typically this will be a transient phenomenon that typically would resolve with anti-inflammatory and cycloplegics therapy. It would typically occur within a day or two of laser rather than at one week's time. Our post-operative examination revealed no obvious choroidal effusion. With a dramatically worsening clinical course after three days of topical steroids and cycloplegics, we believed that systemic steroids would not help much and could add to the complications. Moreover, use of high dose systemic steroids is ill advised in neonates because of potential growth retardation, adrenal suppression and hypertension. We have used systemic steroids on a series of patients with aggressive ROP and noted minimal ocular benefit. Most authorities in pediatric rheumatology recommend keeping the dose of steroids below 1 mg per kg body weight. In these children that dose is not enough to impact the severe proliferative and inflammatory response. To avoid complications like anterior segment ischemia, previous studies3 have suggested to perform scatter laser in the horizontal meridians, to do laser in multiple sittings (but both these would increase the risk of retinal detachment), to use less power while treating these meridians and to use cryo instead of laser as freezing causes less damage to the ocular vessels. But this should not discourage the treating surgeon from being aggressive in the treatment of ROP. We have shown improved visual and anatomic outcomes with early and thorough treatment.4 Anterior neovascularization, anterior fibrovascular proliferation and hypotony prompted us to the diagnosis of anterior segment ischemia. Iris atrophy and cataract were also seen to develop later, which also are consistent with anterior segment ischemia. There was likely an element of inflammation also but we felt ischemia was the predominant mechanism. We too have a lot of reservations about injecting a drug like bevacizumab, in a premature child, and recommend that it only be used in carefully monitored trials or as a lat resort in advanced cases. In this precious neonate who was certainly going to lose an eye, we believe that there was no better alternative available and all standard treatments were exhausted. The parents gave a detailed informed consent for this intervention with the understanding of potential risks, and the outcome was favorable.

Reversible anterior segment ischaemia after carotid endarterectomy

Carotid artery disease has long been implicated in ocular ischaemic syndrome. The classical changes of ocular ischaemic syndrome have not been described to resolve with carotid endarterectomy. Herein, a case of documented carotid artery disease presenting with anterior segment ischaemia and retinal artery emboli is described. Prompt carotid endarterectomy resulted in resolution of most of the anterior segment ischaemic signs within a few days.

Intravitreal bevacizumab (Avastin) for post laser anterior segment ischemia in aggressive posterior retinopathy of prematurity

Aggressive posterior retinopathy of prematurity (formerly known as fulminate/type II/rush disease) occurs in zone 1 or posterior zone 2. Treatment involves extensive near confluent laser ablation of a large area of avascular retina. Anterior segment ischemia is a rare complication that can occur due to injury to the long posterior ciliary arteries in the horizontal meridians during aggressive posterior laser treatment. The outcome of this rare complication is very poor. This case describes a favorable outcome of intravitreal injection of bevacizumab (Avastin) in a case of anterior segment ischemia.

Intraocular Pressure Is Low in Eyes With Giant Cell Arteritis

Although ocular ischemia occurs in giant cell arteritis (GCA), intraocular pressure (IOP) has not been systematically evaluated as a diagnostic sign. We conducted a retrospective, case-controlled, observational study of IOP in patients with ocular manifestations of GCA (GCA patients), age-matched patients diagnosed with nonarteritic ischemic optic neuropathy (NAION patients), and age-matched patients with cataract (control patients). Medical records were examined for all consecutive patients with the diagnosis of GCA from 1995 to 2004 (n = 16) and NAION from 2002 to 2004 (n = 16) and for patient candidates for cataract extraction (n = 16). The eye intended for cataract extraction was chosen as the "affected eye" in the control patients. The mean IOP in the affected eye of 16 GCA patients was 11.9 mm Hg, significantly lower than the 15.1 mm Hg in affected eyes of age-matched NAION patients and 15.8 mm Hg in control patients (P = 0.002). At presentation, 5 GCA patients had IOP < 10 mm Hg (mean 6.8 mm Hg) without other signs of anterior segment ischemia. None of the NAION or control patients displayed such low IOPs. IOP was significantly lower in the patients with GCA than in patients with NAION or cataract. Hypotony occurred in one third of GCA patients without other signs of anterior ocular ischemia. These findings suggest that low IOP may be a distinguishing factor between GCA and NAION in patients with ischemic optic neuropathy, but evaluation of a larger group of patients is needed for confirmation.

Rubeosis and Anterior Segment Ischemia Associated With Systemic Cryoglobulinemia

To report two cases of iris neovascularization associated with systemic cryoglobulinemia. Retrospective case report. Patient chart review and review of literature. Two patients with iris neovascularization in the absence of retinal ischemia were subsequently found to have systemic cryoglobulinemia. Successful treatment of one patient's underlying lymphoma led to stabilization and resolution of neovascularization. Systemic cryoglobulinemia may be associated with anterior segment ischemia and neovascularization, and should be considered in the differential diagnosis of iris neovascularization in the absence of apparent retinal ischemia.

Recession–resection combined with intraoperative botulinum toxin A chemodenervation for exotropia following subtotal ruptured of medial rectus muscle

Ruptured extraocular muscle loses its function and shows severe restriction of eye movement even after muscle-to-muscle anastomosis or muscle transposition surgery. We present the case of a patient who developed a large exotropia after near-total rupture of the medial rectus muscle following a blowout fracture. Case report. A 12-year-old girl presented at our clinic with 45 prism diopters' exotropia after a blunt trauma. A forced duction test was unrestricted, and orbital computed tomography showed a medial orbital wall fracture and an impinged medial rectus muscle. Upon surgical exploration, an almost totally ruptured medial rectus muscle was found. The median margin of the ruptured muscle was 6.0 mm from its insertion, and the distal end that we could examine was 15.0 mm from the limbus. Recession-resection surgery combined with intraoperative botulinum toxin A chemodenervation to the ipsilateral lateral rectus muscle achieved a good primary alignment and binocular single visual field, even at a 9-month follow-up. Recession-resection surgery augmented by intraoperative botulinum toxin A chemodenervation to the ipsilateral rectus muscle appears to be highly effective in the treatment of a large exotropia produced by subtotal rectus muscle rupture following orbital wall fracture, with a lower risk of anterior segment ischemia.