Restrictive strabismus following pterygium excision surgery combined with amniotic membrane transplantation: A retrospective case review

Volume 14 Number 1 / February 2010 111 Restrictive strabismus following pterygium excision surgery combined with amniotic membrane transplantation: A retrospective case review. Anya A. Trumler, Chantal Boisvert, Adele M. Roa, Don O. Kikkawa, David B. Granet Introduction: To report the clinical characteristics of restrictive strabismus following pterygium excision using amniotic membrane transplantation (AMT). Methods: A retrospective review of 11 consecutive patients who presented with restrictive strabismus following pterygium excision surgery combined with AMT in the past 15 months. Results: The mean age on initial strabismus examination was 53 (range, 37-68). Five of the 11 patients underwent pterygium excision with AMT as their primary procedure. All patients eventually had more than one surgery for removal of the pterygium and/or scar tissue, with a maximum of 5 operations. Ten of the 11 patients had diplopia after AMT in at least one field of gaze, 7 of those had diplopia in primary position. Nine patients developed diplopia an average 3.3 months after the first AMT. One person's diplopia worsened after secondary repair with AMT. All patients had incomitant strabismus with the mean angle of deviation in primary position of 10D (range of intermittent exotropia of 2D to 16D of esotropia). Five subjects had an upper eyelid ptosis on the involved side. Conclusions: Given the large number of pterygium procedures performed, awareness of restrictive strabismus and its prevention, is essential if using AMT. The similarities of pterygium repair techniques that may have lead to restrictive strabismus are reviewed as well as the spectrum of surgical options for correction of the resulting restriction. Use of AMT for prevention of pterygium recurrence is associated with restrictive strabismus resulting in diplopia.

112 Non-aneurysmal cranial nerve compression as cause of neuropathic strabismus: Evidence from high-resolution magnetic resonance imaging (MRI). Tzu-Hsun Tsai, Joseph L. Demer Introduction: Clinical syndromes including trigeminal neuralgia, hemifacial spasm, and vestibular paroxysmia are believed caused by cranial nerve (CN) compression by ecstatic or tortuous vessels. Highresolution MRI can now directly demonstrate innervation to extraocular muscles. We used MRI to seek evidence of motor CN compression in otherwise idiopathic neuropathic strabismus. Methods: Surface coils were used to obtain sets of contiguous, 2 mm thick, 320 micron resolution, coronal and sagittal MRI in patients with oculomotor (CN3) and abducens (CN6) palsy. Relationships between motor CNs and intracranial arteries were demonstrated by 0.8 mm thick, 162 micron resolution, heavily T2 weighted axial and sagittal MRI. Results: In one patient with CN3 palsy, an ectatic posterior communicating artery markedly flattened and thinned the ipsilateral subarachnoid CN3. Cross-sections of the affected medial, superior and inferior rectus muscles 10 mm posterior to the globe-optic nerve junction were 17.2  2.5 mm2, 15.5  1.3 mm2, and 9.9  0.8 mm2, significantly smaller than the values of 23.6  1.9, 30.4  4.1, 28.8  4.6 mm2 of the unaffected side (p \ 0.001). In two patients with otherwise unexplained CN6 palsy, ectatic basilar arteries contacted CN6. Mean cross-sections of affected lateral rectus muscles were 24.0  2.3 and 29.8  3.1 mm2, significantly smaller than the values of 33.5  4.1 mm2 and 36.9  1.6 mm2 in unaffected contralateral eyes (p \ 0.05). Conclusions: Non-aneurysmal motor CN compression should be considered as a cause of CN3 and CN6 paresis with neurogenic muscle atrophy, when MRI demonstrates vascular distortion of the in-

Journal of AAPOS

e29 volved CN. While neurosurgical vascular decompression is probably unwarranted, demonstration of a benign vascular etiology can terminate continuing diagnostic investigations and expedite rational surgical management of the strabismus. 113 Refractive outcome after secondary IOL implantation in pediatric aphakia. Deborah K. VanderVeen, Bharti R. Nihalani Purpose: To evaluate accuracy of IOL power calculation and early refractive outcomes of secondary IOL implantation in pediatric aphakia Material and Methods: Retrospective case review of all children with secondary IOL implantation between 1999 and 2009 who received in-the-bag (ITB) or sulcus implantation. Sutured IOL eyes were excluded. Biometry, predicted refraction, and post-operative refractive data were collected and analyzed. Refractive outcome was assessed at 1-2 months post IOL implantation. Prediction error (PE) 5 predicted refraction – actual refraction was calculated. Results: 49 eyes of 32 patients were analyzed. Mean age at secondary IOL implantation was 8.8 years (range, 2-21 years), with mean interval of 7.4 years between primary cataract extraction and secondary IOL surgeries. 27 eyes had ITB and 22 had sulcus IOL. 43 eyes had Acrysof and 6 eyes had PMMA IOL. Mean keratometry at IOL implantation was 44.3, and mean axial length measure was 22.3 but ranged from 20.025.6 mm. Implanted IOL power ranged from 12 to 35 diopters(D). 9 eyes required IOL power .30 D for target refraction. Mean PE was 0.67 + 0.90 for ITB and 0.47 + 1.39 for sulcus IOL. Conclusions: The refractive outcome of secondary IOL in pediatric eyes was satisfactory. Mean prediction error is similar for ITB and sulcus IOLs, but sulcus IOL.has greater variability. Limited IOL power availability in high diopters also limits PE in this population. 114 Posterior capsular opacification after AcrySof one-piece vs three-piece intraocular lens implantation in pediatric cataract patients. Monica Verma, Wassia Khaja, Kimberly Yen Introduction: To compare the incidence of posterior capsular opacification (PCO) and secondary membrane (SM) after cataract extraction/IOL implantation (CE/IOL) with the AcrySof (Alcon) one-piece (SN60AT) vs three-piece (MA60AC) intraocular lens (IOL) in pediatric patients with or without primary posterior capsulotomy (PPC). Methods: A retrospective review of 227 consecutive pediatric patients who underwent CE/IOL with or without PPC by a single surgeon from September 2002 to January 2009. Results: Three hundred twenty seven eyes were included. Seventyeight eyes (23.9%) developed visual axis opacification requiring intervention. A total of 141 eyes underwent CE/IOL with the posterior capsule left intact; the average age of patients at the time of surgery was 5.6 years. Eighty-four eyes received the SN60AT IOL and 57 eyes received the MA60AC IOL. In the SN60AT group, 36 eyes (42.9%) developed PCO an average of 5.5 months following surgery. Four eyes (6.7%) developed recurrent PCO after Yag capsulotomy. In the MA60AC group, 23 eyes (40.4%) developed PCO an average of 7.6 months after CE/IOL with none developing recurrence; average age at the time of surgery was 5.9 years. Average followup time was 1.9 years for the SN60AT group vs 3.2 years for the MA60AC group. Ninety-four eyes underwent cataract CE/IOL with PPC. Sixty eyes received an SN60AT IOL and 34 eyes received the MA60AC IOL. Eight eyes (13.3%) in the SN60AT group developed SM vs 3 eyes (8.8%) in the MA60AC group an average of 3 months after surgery. Average age at the time of surgery was 3.8 and 4.1 years respectively. Followup time was 1.6 years in the SN60AT group and 2.3 years in the MA60AC group. Conclusions: PCO is common following cataract surgery in pediatric patients and the incidence of visual axis opacification is lower