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Total lateral paralysis in a case of "One and half" Fisher's syndrome accompanied by paralytic pontine exotropia is described. Oculographic investigation indicates involvement of the nucleus of the VIth cranial nerve. Paralytic pontine exotropia, may therefore be encountered where the VIth nucleus is involved.
For the past several years, we have been performing unilateral lateral rectus recessions in patients with small- to moderate-angle intermittent or constant exotropia. We report a 73% success rate in 45 patients undergoing 6- to 10-millimeter unilateral lateral rectus recessions in exotropia with a minimum of 6 months' follow up. The success rate increased to 89% for patients under 4 years of age. The advantages of this procedure include operating on only one eye and virtual elimination of overcorrections, thereby preventing early postoperative consecutive esotropia, which occasionally can result in amblyopia or diminished stereopsis in very young children.
PURPOSE: This paper reports an outcome study of 52 consecutive children treated by bilateral lateral rectus recession for intermittent exotropia over a 9 year period (1981-90) with a minimum follow up of 6 months. METHODS: Successful alignment was defined as the absence of any postoperative intermittent or constant tropia in any position of gaze. The study examined the variables that might be predictive of successful alignment. The charts were abstracted for age at initial surgery, quantity of initial deviation, initial refraction, motor alignment at 1 week and 6 months, final alignment, secondary surgery results and the incidence of a monofixation syndrome result. RESULTS: Motor tests demonstrated that 32 (62%) of the patients were successfully aligned by the initial procedure performed for a mean of 25 prism diopters of preoperative deviation while viewing distant targets at a mean age of 4 years 8 months, followed for a mean of 4 years, 4 months. The incidence of undercorrections and overcorrections were approximately equal in quantity suggesting that the current surgical dosage was adequate, but the age at initial surgery, initial deviation, initial refraction and 1 week postoperative alignment results were not predictive of success. Alignment at 6 months, however, was highly correlated with successful alignment by the end of the study (p = 0.002). Secondary surgery was performed for 11 patients and 5 patients were found to have a monofixation syndrome result. CONCLUSION: Successful alignment was achieved in the majority of children treated for intermittent exotropia by an initial bilateral lateral rectus recession. However, 20% of the patients received secondary surgery for a residual deviation, and the study confirmed a previously reported 10% incidence of monofixation syndrome result in children surgically treated for this type of strabismus.
Surgical results after symmetrical and asymmetrical surgery performed by the same surgeon (M.S.) as initial procedure for basic intermittent exotropia were retrospectively analysed in 55 young patients. Twenty-five patients underwent unilateral recess-resect surgery on the non-fixating eye (Groupe 1) and 30 patients bilateral lateral rectus recessions (Group 2). The average age at surgery was 6.5 yrs (range: 2-18). The average post-operative follow-up was 2.81 yrs (range: 0.50-8 yrs), (p = 0.143). Sensory fusion was assessed by the Bagolini straited glasses and/or the Worth test and stereopsis by either the TNO and/or Lang stereoacuity test prior and after surgery. Prior to surgery, 84% of the patients had reached isoacuity. Ocular motility was normal in all patients. The average size of preoperative exotropia measured by prism and alternate cover test was 28 PD (SD = 5) for both Groups. In the immediate postoperative period, 53% of the patients were overcorrected without any statistically significant difference between the 2 groups (p = 0.053). Nine (16%) patients had a "mixed" deviation (from eso- to exo depending of the fixation distance), 8 (15%) patients were orthophoric (20% in Group 1 vs 10% in Group 2) and 9 (16%) patients were undercorrected (12% in Group 1 vs 20% in Group 2). The results at last exam, were similar between the 2 Groups; good or fair alignment was achieved in 29 (53%) patients (p = 0.512); 23 (42%) patients had still X(T) (p = 0.829) and 3 (5%) patients were overcorrected. We concluded that even if the immediate postoperative results seem better with asymmetrical surgery, in the long-term there is no significant difference between the two surgical procedures.
To study the long-range results of surgically treated intermittent exotropia, 100 consecutive patients have been followed up for an average of 6.1 years. In all cases, the initial procedure was bilateral recession of the lateral rectus muscles. The overall functional cure rate was 78%. To accomplish this result, 27 patients were operated on a second time, 21 for undercorrection and six for overcorrection. A number of patients cooperated very poorly or were lost to follow-up while still under treatment. Had these patients been eliminated from the series, the cure rate would have been greater than 90%. In this study, bilateral recession of the lateral rectus muscles corrected the distant measurement more than the near measurement only with the divergence excess type of deviation. Also, this procedure was not notably more effective with divergence excess than with basic-type intermittent exotropia.
The characteristics, methods of clinical investigation, and incidence of amblyopia, suppression, and anomalous retinal correspondence in exotropia have been reviewed from the ophthalmic literature. It is hoped that reemphasizing the sensory anomalies in exotropia may lead to more sensitive clinical investigation in these areas and, ultimately, to a better understanding of the sensory system and some of its enigmatic responses.
The characteristic clinical findings of pseudoparalysis of the medial rectus muscle include exotropia in primary position, widened medial fissure on the affected side, limitation of adduction on the affected side, an A-pattern exotropia, and a paradoxical forced-traction test. We have devised a surgical technique to restore good movement of the eye in adduction. The priniciple behind the technique is that all adhesions between Tenon's capsule covering the muscle and conjunctiva, and between muscle and sclera must be found and cut posterior to the fornix. This will allow the muscle to be brought forward easily so that it can be resected and advanced for restoration of function.
An analysis of 113 exotropia operations showed a reduction of the evodeviation for distance to a residual angle of -9 and -12 delta. In 67 cases with unilateral surgery (recession-resection) each additional millimeter beyond two millimeters produced a reduction of angle of about 3 delta for distance, the variance, however, was considerable. The operation of 58 cases with intermittant exotropia improved the manifestation for distance significantly in 71%.
Sixty cases of intermittent exotropia were studied to compare the outcome of those patients treated medically with the outcome of those patients treated surgically. Below 30 prism diopters of intermittent exotropia, there is a high functional cure rate in both groups. Preoperative orthoptics did not lead to a surgical overcorrection. And finally, central fusion is not essential for a clinical cure.
A study was done of 22 children in whom exotropia developed following correction of hyperopia because of accommodative esotropia that had not been corrected surgically. The early onset of esotropia and high degree of hyperopia seemed to predispose to the spontaneous development of exotropia. Reduction of the hyperopia by 50% to 60% resulted in satisfactory realignment of the eyes and some form of binocularity.
A homonymous hemianopia can be compensated by a strabismus in the direction of the visual field defect if the deviated eye has a harmonious anomalous localization. This compensation is only partial; its extent corresponds to the angle of deviation. We report on two patients with a hemianopia to the left. Under binocular conditions the visual field defect was reduced by an exotropia of the left eye with panoramic vision. Unfortunately, up to now it has not been possible to induce such a sensory-motor compensation in cases of homonymous hemianopia with normal retinal correspondence in an adult visual system.
BACKGROUND: The majority of cases of exotropia with extreme deviations (30-45 degrees or 60-90 prism dioptres) are secondary forms of strabismus, either consecutive, following monolateral combined recession/resection procedures in childhood, extreme anisometropia or following trauma. For the surgical treatment the deviation is often too great to be corrected completely by conventional repositioning of the medial and lateral rectus muscle of the affected eye and patients justifiably refuse an operation even on the main eye because the indications are mostly more aesthetic than functional. METHODS: The paper presents a technique of a free mucosa transplant. The effect can be strengthened and made more secure following repositioning of the muscle. RESULTS: With this method even extreme deviations (up to 45 degrees corresponding to 90 prism dioptres) could be successfully and permanently corrected by surgery on the deviated one eye only. CONCLUSIONS: This method provides a new option for patients who are often incorrectly told that their deviation cannot be corrected by monolateral surgery.
PURPOSE: To evaluate the convergence accommodation to convergence (CA/C) ratio in strabismic patients and to clarify its clinical implications. METHODS: Seventy-eight consecutive patients (mean age: 12.9 +/- 6.0 years) with intermittent exotropia and decompensated exophoria who showed binocular fusion at least at near viewing were recruited. The CA/C ratio was estimated by measuring accommodative responses induced by horizontal prisms with different magnitudes under accommodation feedback open-loop conditions. The CA/C ratios were compared with accommodative convergence to accommodation (AC/A) ratios and other clinical parameters. RESULTS: A linear regression analysis indicated that the mean (+/-SD) CA/C ratio was 0.080 +/- 0.043 D/prism diopter or 0.48 +/- 0.26 D/meter angle. There was no inverse or reciprocal relationship between CA/C and AC/A ratios. The patients with lower CA/C ratios tended to have smaller tonic accommodation under binocular viewing conditions and larger exodeviation at near viewing. CONCLUSIONS: The CA/C ratio, like the AC/A ratio, is an independent parameter that characterizes clinical features. A lower CA/C may be beneficial for the vergence control system to compensate for ocular misalignment with minimum degradation of accommodation accuracy.
BACKGROUND: The surgical management of intermittent exotropia, or X(T), remains a challenge. Not only are some quoted success rates relatively low (40-83%), but the outcome is notoriously unpredictable with a tendency to exotropic drift over time. METHODS: In this retrospective study, 118 patients who underwent either bilateral lateral rectus muscle recession (BLR) or unilateral medial rectus muscle resection and lateral rectus muscle recession (R&R) surgery during a 4-year period were reviewed. Surgical outcome between the 2 groups in addition to factors that influence outcome within groups were analyzed. Success was defined as an X(T) < or = 10PD. RESULTS: Sixty-four subjects underwent BLR, and 54 subjects underwent R&R surgery. Mean preoperative distant X(T) size was 38.7 +/- 6.7 PD. Subjects who underwent R&R did significantly better at 1-year follow-up (success 74.2% vs. 42.2%) but showed significantly more exotropic drift over time (P = 0.01). Within both BLR and R&R groups, subjects with basic-type X(T) did worse than those with divergence-excess X(T) at 1-year follow-up. Consecutive esotropias, however, were more likely with R&R surgery and in those with divergence excess X(T). Preoperative strabismus control, distant X(T) size, and patient age at surgery did not significantly influence outcome. CONCLUSION: In many cases, selection of surgery type continues to depend on the surgeon's preference, which is in turn influenced by his/her past experiences. The debate about which surgical type is best for different X(T) types continues.
Laser in situ keratomileusis (LASIK) is a common and popular procedure that is generally associated with excellent results and few complications. We present 3 cases of unusual LASIK-related complications. In the first case, the patient developed anisocoria after otherwise unremarkable surgery. In the second case, the patient developed mild eyelid ptosis. In the third case, the patient's exotropia resolved after mild refractive overcorrection. In each case, the visual outcome was excellent and no further intervention was necessary.
The purpose of this study was to determine the passive length-tension characteristics of horizontal recti muscles in patients with non-restrictive horizontal strabismus. A system to measure intraoperative continuous-registration passive length-tension curves of detached extraocular muscles was designed. The size of the preoperative deviation and the change in the deviation as a result of surgery was correlated with the passive tension of the medial rectus muscle in patients with acquired esotropia. Patients with infantile esotropia or intermittent exotropia showed no relationship between passive tension and either preoperative deviation or response to surgery. Surgical recession of both the medial and lateral recti muscles produced large changes in the passive tension characteristics of both of these muscles. Medial rectus muscle recession produced larger changes in the passive tension than equal amounts of recession of lateral recti muscles.
We studied the coordination of binocular eye movements in human subjects with alternating exotropia (divergent strabismus). Binocular saccades were recorded in six subjects during binocular and monocular viewing. Subjects were instructed to make saccades between two continuously lit targets (LED's) presented in an isovergence array (with the straight-ahead target 130 cm from the eyes) in a dimly lit room. For saccades up to 20 degrees amplitude, there were no large differences in the dynamics of the saccades between control and exotropic subjects. However, for larger amplitudes subjects frequently alternated the eye of fixation during saccades. That is, subjects fixated the left target with the left eye and the right target with the right eye. The alternation in eye fixation at the end of the saccade was taken into account in the programming of the saccades. The amplitudes of the alternating saccades were approximately equal to the target amplitude minus the strabismus angle. We conclude that for those saccades where alternation occurs, there is not only a change in the eye of fixation, but also a change in the target representation provided by either eye. Thus, in this group of strabismic patients, saccades may be programmed in a retina-centered coordinate system, if we assume that for making a saccade to a new target in the contralateral visual field its representation on the temporal retinal field of the currently fixating eye is suppressed and the retinotopic target information is derived from the non-fixating eye. In executing the saccade, the non-fixating eye automatically becomes the fixating eye.
OBJECTIVE: To evaluate the efficacy of slanted recession of the lateral rectus (LR) muscle for exotropia (XT) with convergence weakness. DESIGN: Predesigned, nonrandomized, comparative trial. PARTICIPANTS: Twelve study patients and six control subjects with XT greater at near than at distance by > or =10 prism diopters (PD). INTERVENTION: Twelve consecutive patients underwent slanted LR recession, and six consecutive control subjects underwent standard LR recession. MAIN OUTCOME MEASURES: Between-groups comparison of the postoperative ocular alignment at distance and near, and the difference between them, as well as the stereopsis. RESULTS: Slanted LR recession reduced the XT to <8 PD in all patients at distance and in 11/12 patients at near. Additionally, the mean difference between the distance and near exodeviation was reduced from 14+/-4.5 PD preoperatively to 2.9+/-2.4 PD postoperatively. All patients in the control group demonstrated postoperative deviations of <8 PD at distance, but all had residual exodeviations >8 PD at near. Three of the study patients gained gross stereopsis postoperatively. CONCLUSIONS: Slanted recession of the LR is superior to standard recession in reducing both distance and near XT and in collapsing the difference between them. This technique may also have a positive impact on gross stereopsis.