Epidemiology of CN IV Palsies.

OBJECTIVE: To examine the etiologies of CN IV palsies based on age and aid the clinician in more effective work-up and treatment. METHODS: Retrospective chart review of 124 patients presenting to Houston Eye Associates between 1968 and January 1999 with superior oblique palsies. Patients were divided into the following age groups: birth to 10 years, 11-20 years, 21-40 years, 41-60 years and over 60 years. Etiologies and treatment were then examined within each age group. Etiologies were categorized as congenital, traumatic, vascular, neoplastic, and idiopathic. Treatment was classified as observation, prisms alone, surgical repair, and surgical repair combined with prisms. Bilateral, unilateral, and masked bilateral palsies were included. RESULTS: Nine of 13 bilateral palsies were due to trauma. The masked bilateral palsy was congenital. Between the ages of birth and 10 years 26 of 37 (70.1%) palsies were congenital. Between the ages of 21 and 40 years 17/35 (48.6%) were due to trauma. Within the remaining age groups 11-20 years, 41-60 years, and over 60 years, the most common etiology was idiopathic 7/13 (53.8%), 11/24 (45.8%), and 7/15 (46.7%) respectively. Surgery was the most common treatment option within all age groups with the exception of the over 60 group. In this age group, prisms alone was most common.

1999 Costenbader Lecture. Outcome study in amblyopia: treatment and practice pattern variations.

This study retrospectively evaluates the results of amblyopia therapy and suggests hypotheses for future study. We address the various methods of treatment and evaluate the results from the most common therapy techniques. Practice pattern variations were analyzed in addition to the analysis of overall results. For ophthalmologists, there is a need to determine whether actual medical practice approaches the established standard of care, if it exists at all. How often are medical procedures, thought to be appropriate, based on anecdotal observation (case reports) rather than hard data (clinical trials)? The 3 types of vision loss evaluated were strabismic, anisometropic, and deprivation amblyopia. The methods of treatment studied were full-time patching part-time occlusion, penalization, and occlusion of the contact lens. Nine centers, thought to have private as well as indigent patients, were recruited to participate in this study. The centers responded by filling out an extensive questionnaire and sending the information through the World Wide Web for inclusion in a spreadsheet. This information was then collated, and various statistical programs tabulated the results. Although trends, as a consequence of therapy, are suggested from our retrospective analysis, concrete results can only arise from a randomized prospective study. The study included 279 patients. There were a similar number of male and female patients. Only 77% of the patients without fusion before treatment had either single binocular vision or peripheral fusion at the conclusion of therapy. The log improvement of vision was significant in each group. Factors that potentially influenced the results were severity of distance acuity in the amblyopic eye before treatment, duration of treatment, and length of daily patching. The paper suggests that worse vision, not better vision, at the beginning, predicts better outcome in terms of improvement of visual acuity. For example, visual acuity less than 20/70 at the initiation of treatment led to better visual results of geometric log improvement. Surprisingly, among the 9 centers studied, there was a statistically significant difference in many of the areas related to practice patterns. Patient compliance, which directly affects outcome, was highly variable and is a factor that may be readily influenced by the treating physician.

Cluster of diplopia cases after periocular anesthesia without hyaluronidase.

PURPOSE: To describe a cluster of cases of iatrogenic diplopia after cataract surgery that occurred in 1998, when hyaluronidase was unavailable for use in periocular anesthetic regimens. SETTING: The clinical practices of the authors. METHODS: This study comprised a retrospective chart review. RESULTS: Twenty-five cases of transient or permanent diplopia were reported. Of these, 13 eyes had retrobulbar and 10 had peribulbar injections; in 2 cases the injection technique was unknown. The inferior rectus was affected in 19 eyes; of these, 1 had a temporary palsy and 18 had permanent restriction. Temporary paresis developed in the lateral rectus in 5 cases and the superior rectus in 2. Eleven cases were submitted by 4 anterior segment surgeons, who collectively had a zero incidence of iatrogenic postoperative diplopia in the preceding 4 to 11 years of practice (approximately 6900 cases). CONCLUSION: Hyaluronidase may be more important than previously suspected in preventing anesthetic-related damage to the extraocular muscles. The inferior rectus muscle is particularly vulnerable, presumably because of the injection technique.

Accuracy of the Nidek ARK-900 objective refractor in comparison with retinoscopy in children ages 3 to 18 years.

PURPOSE: To compare the increased speed and accuracy of the Nidek ARK-900 objective refractor with standard retinoscopy. METHODS: In a prospective study, 100 children aged 3 to 18 years were refracted after cycloplegia. Visual acuity measurements were determined in randomized fashion with the Nidek objective refractor, by retinoscopy, and by subjective refraction. One eye from each patient was included in the study. RESULTS: Ninety-six percent of the children read the 20/30 line perfectly with the result from the objective refractor compared to 88% with retinoscopy. The mean +/- SD visual acuity value obtained with the objective refractor was 20/24 +/- 4.75 and with retinoscopy was 20/27 +/- 6.8, a significant difference (paired t value = 4.81, P < .001). CONCLUSION: The Nidek ARK-900, representing the third generation of objective refractors, is comparable or superior to retinoscopy in accuracy in children, can be easily run by an ophthalmic technician, and therefore eliminates the physician's examination time required for retinoscopy.

NGF prevents the changes induced by monocular deprivation during the critical period in rats.

Photic evoked responses were recorded from the striate cortex of Long-Evans hooded intact, monocular visual deprivation (MD) and MD treated with NGF rats. The averaged visual evoked responses (AVER) were obtained from both hemispheres and provided comparison after binocular photic stimuli between the contralateral and the ipsilateral striate cortex with relation to the MD eye. One month of monocular visual deprivation at the critical period of development resulted in marked reduction of the amplitudes of AVER components as compared to the control recordings (P < 0.001). These changes of the AVER could be prevented by NGF infusion to lateral ventricle at the dosage of 2.0-2.4 micrograms/day for four weeks during the monocular deprivation. In conclusion, the change of AVER amplitudes induced by monocular visual deprivation during the critical period of development can be prevented by NGF infusion to lateral ventricle.

Visual deprivation at the critical period modulates photic evoked responses.

Average visual evoked responses (AVER) were recorded from the striate cortex of normal (control) and monocular visually deprived Long-Evans hooded rats. One month of monocular visual deprivation (MD) at the critical period of development resulted in marked reduction of all the three AVER components (i.e., components P2, N2 and P3) as compared to the control recording (P < 0.001). In control animals, the AVER amplitudes of the two hemispheres were identical, while in MD rats, the P2 and N2 components of the AVER obtained from the hemisphere ipsilateral to the MD eye were markedly smaller than those of the AVER obtained from the contralateral hemisphere (P < 0.001). The latencies of the late components (N2 and P3) obtained from the hemisphere ipsilateral to the MD eyes were significantly delayed as compared to those from the contralateral hemisphere (P < 0.05 for N2, P < 0.01 for P3). The AVER following paired photic stimuli with various time intervals between the stimuli were used to study the neuronal recovery function of control animals compared to MD animals. The AVER to the second stimulus obtained from the MD rats exhibited greater attenuation in their amplitude responses than the AVER obtained from the control group, i.e., slower neuronal recovery. The neurophysiological changes observed in this study may relate to the neurocytological alteration occurring in the striate cortex following monocular visual deprivation at the critical period. In conclusion, AVER recorded from monocular visually deprived rats during the critical period is a simple and reliable electrophysiological animal model to study neuroplasticity during postnatal development.

Monocular visual deprivation at the critical period modulates photic evoked responses.

Photic evoked responses were recorded from the striate cortex of Long-Evans hooded normal (control) rats and from monocular visual deprivation (MD) rats. The averaged visual evoked responses (AVER) were obtained from both hemispheres and provide comparison between the contralateral and the ipsilateral striate cortex with relation to the monocular deprived eye. The AVER recorded following binocular photic stimulation after 1 month of monocular deprivation demonstrated that the two visual cortexes responded differently. In the contralateral hemisphere of the visual cortex (related to the MD eye), all three components (P2, N2 and P3) of the AVER of the MD rats had significant increases in their peak amplitude as compared to the control recordings. In the ipsilateral cortex, the amplitude of component P2 and N2 was significantly reduced as a result of 1 month of MD. Comparing the AVER amplitudes of the two homotopic sites of the visual cortex obtained from the control group reveals no differences between the two hemispheres but markedly significant differences in P2, N2 and P3 components for the MD group. Based on the literature, the possibility that the monocular visual deprivation at the critical period in early developmental stage modulates the AVER as a result from the neurocytological alteration from altering of GABA and ACh within the striate cortex was discussed. In conclusion, the AVER is a reliable and practical method for studying the effects of monocular deprivation and neuroplasticity in the rat visual cortex.

Pediatric ocular trauma: a retrospective survey.

A retrospective, cross-sectional survey was conducted of all pediatric trauma cases seen by the ophthalmology department at our institution from January 1986 to December 1991. The study included 504 patients who were 15 years old or younger. The purpose of this study was to determine risk factors for ocular injury, especially injury resulting in severe visual impairment, and to identify trends and preventable causes. Our results were consistent with the findings of other similar studies: male patients predominated, penetrating injuries resulted in poor visual outcomes, and many of the causes of severe visual deficit were preventable with more adequate adult supervision.

Clinical characteristics and long-term postoperative results of infantile esotropia.

We classified 103 patients (206 eyes) with infantile esotropia and an average of 8.7 years of postoperative follow-up into four outcome groups. Of 103 patients, 28 (27%) had subnormal binocular vision; 24 (23%) had microtropia; 43 (42%) had small-angle deviation (< 20 prism diopters); and eight (8%) had large-angle deviation. A chi 2 analysis showed a significant difference (chi 2 = 16.22, P = .005) in the distribution of amblyopia among these four outcome groups. Visual acuity of 20/30 or better was attained in 174 of the 206 eyes (84%). The eyes of all 28 patients in the subnormal binocular vision group remained aligned after an average of eight years. In contrast, the eyes of six of 30 patients (20%) in the microtropia group and 11 of 43 (26%) in the small-angle deviation group lost the stability of horizontal alignment. We found that the two variables of latent-manifest nystagmus and persistent amblyopia at the time of surgery lead to less satisfactory outcomes. In contrast, patients with smaller preoperative angle of deviation or surgery completed before 1 year of age demonstrated an increased incidence of optimal (subnormal binocular vision) or desirable (microtropia) results. We recommend performing surgery after amblyopia has been thoroughly treated, and, whenever possible, completing the surgical treatment by 1 year of age.

The antiemetic effect of lorazepam after outpatient strabismus surgery in children.

The high incidence of postoperative emesis after strabismus surgery in pediatric outpatients can be reduced by the prophylactic administration of droperidol 75 micrograms/kg intravenously. However, this may be associated with profound sedation, delayed discharge, dysphoria, agitation, and extrapyramidal symptoms in this population. Because lorazepam used as an antiemetic in children during chemotherapy decreased the incidence of nausea and vomiting, we compared the antiemetic effects of lorazepam and droperidol in a randomized, double-blind, placebo-controlled study of 129 healthy children undergoing surgical correction of strabismus. The children, aged 1-13 yr, were randomly allocated into three groups. The children in group 1 received droperidol 75 micrograms/kg intravenously; those in group 2 received lorazepam 10 micrograms/kg intravenously; and those in group 3 received placebo. Anesthesia consisted of halothane, nitrous oxide in oxygen, and atracurium. Study drugs were administered intravenously after induction of anesthesia but before surgery. In children 3-13 yr old, administration of either lorazepam or droperidol was associated with a lower (P < 0.024) incidence of postoperative vomiting. There was no difference between the antiemetic effect of lorazepam and that of droperidol. The incidence of postoperative agitation was greater in the droperidol group (P < 0.001) than in the lorazepam and placebo groups. Postdischarge vomiting was less (P < 0.009) in children younger than 3 yr of age. Lorazepam, similar to droperidol, has an antiemetic effect in outpatient children 3-13 yr old undergoing strabismus correction, but it is associated with less postoperative agitation than is droperidol.

Goniotomy with sodium hyaluronate.

A modification of the classical goniotomy technique is described. After complete evacuation of the anterior and posterior chambers, sodium hyaluronate is placed in the anterior chamber and on the cornea. Putting hyaluronate in both locations prevents the formation of air bubbles under the goniotomy lens, provides the same index of refraction on both sides of the cornea, prevents accidental loss of the anterior chamber, and allows maximal depth of the anterior chamber. Diminished intraocular bleeding and lower risk of injury to the corneal endothelium, iris, and lens may be additional advantages of the procedure. Two cases are presented in which five goniotomies were performed on four eyes using this technique. Both patients had one eye controlled with a single goniotomy. The fellow eye of each patient required multiple procedures. Glaucoma was controlled successfully with no medication in all four eyes. No significant complications occurred.

Monocanalicular lacrimonasal intubation.

A new technique to obtain patency of the lacrimal drainage system was used in three children with bilateral congenital obstruction of the lacrimonasal duct (six cases) and upper canalicular abnormalities (five cases). The upper canalicular abnormalities prevented bicanaliculonasal intubation.A silicone tube was passed through the lower canaliculus, traversing the lacrimal drainage system and into the nasal fossa. The proximal end of the tube was placed subconjunctival in the inferior fornix and secured. The distal end of the tube was passed through the subcartilaginous nasal septum to the contralateral nasal fossa and tied to a tube similarly passed through the opposite lacrimal system.The procedure was successful in all six cases, with all tubes remaining in place the desired length of time. Postoperative identification and removal of the tubes offered no difficulties and was followed by permanent patency of the lacrimal drainage system in all six cases.

Effectiveness of botulinum toxin therapy for essential blepharospasm.

The effectiveness of Botulinum toxin (Oculinum) therapy in 76 patients with the diagnosis of essential blepharospasm was analyzed. Botulinum offers relief to almost all patients suffering from essential blepharospasm, however, this relief is usually temporary. The response time for repeated treatments tended to be longer than the first treatment. Patients with mild blepharospasm responded significantly longer to Botulinum injection, than those with severe spasms. The response to Botulinum was not significantly different in patients with Meige syndrome than in patients with only essential blepharospasm. Patients previously treated surgically for essential blepharospasm did not respond differently than those patients with no previous surgical therapy. The authors believe that Botulinum toxin injection is an effective, although temporary, mode of therapy for the signs and symptoms of this focal dystonia. The authors recognize that there may be psychologic factors affecting the response.