Biomedical subjects
Publications and source records attributed to M X Repka.
We present two cases of meningioma obstructing the posterior sagittal sinus, producing elevated intracranial pressure and papilledema by impairing cerebral venous drainage. In both patients, this mechanism was not recognized preoperatively and resulted in optic atrophy and significant visual loss.
Of 196 patients with anterior ischemic optic neuropathy, 169 had the nonarteritic form and 27 had the arteritic type. Visual acuities were 20/40 or better in 83 of 184 eyes with nonarteritic anterior ischemic optic neuropathy but only eight of 45 eyes with the arteritic type. We found systemic disease associations for hypertension and diabetes mellitus only for patients with nonarteritic anterior ischemic optic neuropathy who were between 45 and 64 years of age. After a mean follow-up period of five years, 92 nonarteritic patients showed no changes in the first affected eye; there was eventual involvement of the second eye in 20 patients.
A 13-month-old boy and a 2-week-old girl, who were considered to be anophthalmic and who later each developed a cystic lesion in the left orbit with protrusion of the lower eyelid, were studied. The fellow eye in case 1 was subsequently found to be microphthalmic with cyst and was normal in case 2. Histopathologic study of each case revealed a cyst lined externally by dense fibrous connective tissue to which skeletal muscle and adipose tissue were attached. The inner aspect of the cyst was lined by neuroglial tissue, possible immature retinal tissue, and cuboidal epithelium. No fully developed ocular structures or microphthalmos were identified. Fourteen cases of congenital cystic eye, including our cases, have been published in the English-language literature since 1964. We discuss and illustrate the findings in our cases and 10 others in which histopathologic findings were reported. Congenital cystic eye, microphthalmos with cyst, and microphthalmos with cystic teratoma should be suspected in patients with a small or unrecognizable eye and an orbital cystic mass that is detected by palpation or visualization.
Adjustable suture strabismus surgery may reduce the frequency of reoperations by reducing immediate postoperative over- and undercorrections. We reviewed 290 strabismus procedures performed with an adjustable suture technique. Thirty-five patients required additional surgery, for a reoperation rate of 9.7%. Reoperation frequencies for patients undergoing non-adjustable procedures average approximately 20% in our experience and in reported series. Our low reoperation rate with adjustable strabismus surgery supports our clinical impression that more accurate results are possible with this technique in appropriate patients.
The hang-back recession is a simple, safe alternative to conventional recession. We evaluated the surgical results in 23 consecutive patients undergoing bilateral hang-back lateral rectus recessions and 24 consecutive patients undergoing bilateral conventional lateral rectus recessions. The 6-week postoperative success rate was 78% in the hang-back group and 75% in the conventional group. At the time of the most recent follow-up, the success rate was 64% in the hang-back group and 85% in the conventional group. Dose-response curves were similar for both methods. There were more late overcorrections with the hang-back technique. We suggest modified surgical guidelines for the hang-back recession technique.
The use of "hang-back" suspensions has been shown to be an effective means of weakening rectus muscles. The exact position where the muscle reattaches to the globe has, however, been questioned. We performed eight large hang-back recessions on the rectus muscles of cynomolgus monkeys. Eight weeks postoperatively the attachment sites were determined by reexploration. Six of the recessions were within 0.5 mm of the intended site. The muscles were found an average of 0.4 mm anterior to the intended position. These results confirm that the muscle reattaches close to the intended location. Eight exaggerated recessions were similarly performed; these were more variable in the site of reattachment. Only three muscles were reattached within 0.5 mm of the intended site. There was a mean forward reattachment of 1.1 mm. Four of the 16 muscles were found reattached by a pseudotendon rather than directly to the sclera.
The prevalence of significant lateral incomitance in patients with nonparetic exotropia is reported to be 22%. We speculated that measurement artifact may be the cause for some cases of apparent lateral incomitance. We measured the effective power of plastic ophthalmic prisms using a helium-neon laser in the frontal plane position and at 10 degrees, 20 degrees, and 30 degrees of rotation from the frontal plane. The rotated prisms represented the situation in which a neutralizing prism rotates with the head during measurement of lateral gaze positions. For prisms of 35 prism diopters or more, even 10 degrees of rotation produced significant artifactual incomitance. For smaller prisms, 20 degrees or more of rotation was necessary to induce significant lateral incomitance. We prospectively measured 40 consecutive patients with exotropia. Only three patients (9%) had true incomitance greater than 5 delta, and only one had incomitance in both directions of gaze. Significant lateral incomitance could be induced in every patient examined by improperly positioning the neutralizing prism. Because the detection of lateral incomitance causes most strabismus surgeons to reduce the amount of surgery they perform, special care is necessary when measuring deviations in lateral gazes.
Results of the Prism Adaptation Study (PAS) indicate that prism adaptation improves the success rate of strabismus surgery for patients with acquired esotropia. Patients who show a fusion response to the prisms benefit most from this preoperative treatment. This study analyzes the characteristics of those patients who were and were not prism responders in the PAS. Significant factors predicting a prism response included: patients who were older at the time of onset of their esodeviation (P = .007), duration of deviation less than 1 year (P = .04), alternating fixation (P = .003), fusion on the Worth four-dot test at near with prism neutralization (P = .008), and equal vision (P = .009). Demographic characteristics were similar for both responders and nonresponders except that non-Hispanic patients were significantly more likely to respond to prisms than Hispanic patients (P less than .002). No test or characteristic was found which could reliably predict the prism response. Therefore, all patients with acquired esodeviations should be considered candidates for prism adaptation prior to strabismus surgery.
Limited data exist on the recovery of ocular motility after adjustable suture strabismus surgery performed under local anesthesia. The timing of adjustment has been chosen empirically and has varied widely. We sought to more precisely quantify the recovery of motility by measuring ductions before and after surgery with a modified arc perimeter. Twenty-one eyes of 20 patients were studied. All patients underwent adjustable suture strabismus surgery under retrobulbar or peribulbar anesthesia using 2% lidocaine with hyaluronidase. Mean ductions orthogonal to the field of action of the operated muscle(s) returned to 90% of preoperative levels between 5 and 6 hours after injection. We recommend adjustment 6 or more hours after injection, or at least 5 to 6 hours postoperatively, when 2% lidocaine with hyaluronidase is used for local anesthesia.
Three hundred twenty-two patients underwent strabismus surgery for acquired esotropia according to a rigid protocol in the Prism Adaptation Study (PAS). This report describes the PAS surgical technique and the methods used to evaluate and assure adherence to the surgical protocol. We present analyses of the discrepancies between the amount of recession surgery planned by the surgeon and the amount of recession estimated by the masked graders from documentary photographs. In 74% of patients, the total discrepancy (combined from both medial rectus operations) was 1 mm or less. There was a distinct trend for masked graders to estimate larger recession amounts than were dictated by the protocol and claimed to be done by the surgeon. In 24% of patients, the masked graders estimated that the recession was more than 1 mm greater than that claimed by the surgeon, while in 2%, the graders estimated that the surgery was more than 1 mm less than planned. Of the 74 patients for whom the graders' estimated total recession was more than 1 mm greater than the amount planned by the surgeon, 88% were successful. Of the six patients for whom the graders' estimated total recession was more than 1 mm less than the amount planned by the surgeon, five (83%) were successful. We propose new surgical tables for patients with acquired esotropia. Enhanced amounts of recession appear to be necessary to decrease the rate of undercorrection for each group of patients.
Whether or not eyelid position changes are caused by vertical rectus muscle surgery is controversial and poorly understood. We reviewed pre- and postoperative photographs of patients who underwent recession or resection of one or more vertical rectus muscles in a 10-year period. A change in eyelid position occurred frequently with vertical rectus muscle surgery. With superior rectus recession, 91% of the patients developed upper lid retraction. With inferior rectus recession, 94% of patients developed lower lid retraction. With inferior rectus resection, every patient developed lower lid advancement with accompanying flattening. We describe an adjustable surgical technique to prevent lower lid retraction associated with inferior rectus recession. The technique involves a separate adjustable suspension of the lower eyelid retractors from the inferior rectus insertion at the time of strabismus surgery. The lid position can then be adjusted separately at the time of muscle adjustment. After an average 2 1/2-month follow up, no statistically significant lid retraction could be measured in six patients who underwent the adjustable lid suspension, while statistically significant retraction (P < .01) developed in a group of nine patients who had inferior rectus recession alone. This technique did not limit the success of the strabismus surgery.
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Residency training involves surgery by resident surgeons at various levels of experience and proficiency, supervised by an experienced attending physician. We reviewed the results of strabismus surgery performed at four institutions with two residency training programs. Five hundred twenty-two cases with follow up greater than 6 weeks were evaluated. These cases included 315 attending procedures and 207 resident procedures under direct attending supervision. Success was defined as a strabismic deviation of 8 prism diopters or less. Average postoperative follow-up was 57 weeks and did not differ between groups. There was no statistical difference between the resident success rate of 58% (121/207) and the attending success rate of 69% (217/315) after adjusting for population differences. The average final deviation of the patients postoperatively was 7 delta for the attending group and 10 delta for the resident group. Amblyopia was significantly more frequent in the resident cases (P < .001). Adjustable sutures were used significantly more often in attending cases (P < .0001). This study supports the premise that resident strabismus surgery is as successful as attending surgery.
Esotropia from chronic sixth nerve palsy or paresis usually requires surgery. Chemodenervation of the antagonist medial rectus muscle, while popular for the treatment of acute sixth nerve palsies and pareses, has not been used extensively for chronic cases. In this study, 22 patients with sixth nerve palsies or partially recovered palsies of greater than 5 months duration were treated with chemodenervation. The etiologies of the sixth nerve palsies were trauma (n = 7), tumor (n = 4), infection/inflammation (n = 3), nerve compression from aneurysm or increased intracranial pressure (n = 4), congenital (n = 1), ischemia (n = 2), and idiopathic (n = 1). The mean preinjection deviation was 41 prism diopters. A total of 38 injections were administered (mean, 1.7 per patient). Each patient received an injection of 2.5 to 7.5 units (mean, 4.1) of botulinum neurotoxin A to the ipsilateral medial rectus muscle. Treatment success was assessed 6 months after the last injection. A course of chemodenervation significantly improved the alignment of 9 of the 22 patients (41%). The mean postinjection deviation was 8 delta. Seven patients (32%) had single binocular vision in primary position restored. These patients had a mean horizontal binocular field of 70 degrees (range, 40 degrees to 100 degrees). Thirteen patients (59%) had only modest improvement and required surgery. The data suggest that injection of botulinum neurotoxin A is a useful treatment for some patients with chronic sixth nerve weakness. A course of chemodenervation therapy compares less favorably with transposition surgery with concomitant neurotoxin injection for the treatment of these difficult problems.
The conventional surgical treatment for acquired esotropia with increased accommodative convergence/accommodation ratio consists of bilateral medial rectus recessions of graded amounts based on the distance deviation while wearing full hyperopic correction. This retrospective study was undertaken to determine whether surgery was more successful when performed for the distance or near deviation measured through the distance correction. Surgical success was evaluated by 1) long-term motor alignment of < or = 10 prism diopters of eso- or exotropia at distance and near, 2) sensory fusion as determined by Worth 4-Dot at 33 cm and Randot II stereo acuity testing, and 3) the continued need for bifocal or spectacle correction. Nine patients underwent surgery for their distance deviation measured with full hyperopic correction; all (100%) were successful by alignment and eight of nine (89%) by sensory criteria. Twenty-five patients underwent surgery enhanced by 1.0 to 6.5 mm per eye over the dose of surgery for the distance angle (average 3.1 mm); 20 of 25 (80%) were successful by alignment criteria and 21 of 25 (84%) were successful by sensory criteria. Two of nine patients (22%) in the distance target angle group and 13 of 25 patients (52%) in the near target angle group were able to discontinue spectacles and maintain satisfactory alignment. Six of nine (67%) patients in the distance angle group were able to discontinue bifocals, while every patient in the near angle group was so benefited. No patient in the distance target angle group, but two patients in the near target angle group, required a second operation.(ABSTRACT TRUNCATED AT 250 WORDS)
This study evaluated the ophthalmological outcome following sixth nerve palsy or paresis in 64 children 7 years of age and younger. The outcomes considered were vision, residual strabismus and the need for strabismus surgery. Etiologies included tumor, hydrocephalus, trauma, infection, malformation, and idiopathic and miscellaneous causes. Strabismus surgery was performed on 24% of the patients, with residual strabismus present in 66% of the patients. Neurologists and ophthalmologists should monitor visual acuity in these young children at frequent intervals be prepared to institute amblyopia therapy early in the course of the ocular misalignment if permanent visual disability is to be avoided.
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INTRODUCTION: Parkinson's disease is associated with multiple abnormalities of both the afferent and efferent visual systems. Blepharospasm, paucity of blinking, apraxia of lid opening, visual neglect, reduced vergence, reduced upgaze, and blurred vision are reported findings in these patients. The association of these findings with the disease, and their duration, severity, and treatment have not been systematically investigated. PATIENTS AND METHODS: Patients with Parkinson's disease were prospectively examined. An age-matched control group was recruited from accompanying family members and volunteers. Data recorded included presence of visual complaint, the severity of the Parkinson's disease by Hoehn and Yahr Stage (scale = 1 to 5), duration of disease, pharmacologic therapy, visual acuity, ocular motility, accommodation, convergence amplitudes, and the near point of convergence. RESULTS: Thirty-nine patients were entered into each group, each with 21 men and 18 women. The average patient had had the disease for 8.9 years with a severity index of 2.6. Asthenopia, upgaze deficiency, and convergence insufficiency were significantly more common in the patients with Parkinson's disease than in the controls. Mean geometric visual acuity was poorer in the Parkinson's patients (20/39 compared with 20/28); P < .001). DISCUSSION: Visual complaints were significantly more common in the Parkinson's patients than in the age-matched controls. The frequency of ocular abnormalities was not related to the duration of the disease. Increasing severity seemed to be correlated with the presence of convergence insufficiency and a decline in acuity.