Long-term management of strabismus with multiplerepeated injections of botulinum toxinRichard Gardner, MBBS, DCH, FRANZCO, Emma L. Dawson, DBO,Gillian G. Adams, FRCS(Ed), FRCOphth, and John P. Lee, FRCS, FRCP, FRCOphth
BACKGROUND In the healthcare system in the United Kingdom, a number of patients may be offeredbotulinum toxin as an alternative to surgery in the treatment of their strabismus. Wereport on our experience of treating those who have received 25 or more injections.
METHODS A retrospective review of the botulinum toxin clinic database was used to identifypatients who underwent 25 or more injections between November 1982 and January2006. All patients with strabismus who met this criterion were included. A statisticalanalysis was performed in which we compared aspects of this group with those whohad received 24 or fewer injections.
RESULTS Fifty-seven patients (0.90%) fulfilled our criteria. There were 37 women and 20 men, witha mean age at first injection of 39 years (range, 15 to 80 years). The number of injectionsper patient ranged from 25 to 68 (mean, 34). The duration of treatment was between 3 and22 years. The time interval between injections tended to increase in most patients and theangle tended to reduce. There was no statistical difference between the age at firstinjection, sex, site injected, diagnosis, and complication rate between the long-term groupand the group that received 24 or fewer injections. The long-term group, however, hadundergone more previous operations ( p � 0.001) and had a lower degree of binocularity( p � 0.001).
CONCLUSIONS The treatment of strabismus with botulinum toxin on a long-term basis is practicable andvaluable in patients with poor binocular potential, complicated strabismus, or multiple pre-vious strabismus operations. A trend toward fewer injections with time was observed, and nosignificant adverse effects were observed with long-term treatment. ( J AAPOS 2008;12:569-575)
I n the long-term management of strabismus, surgeryremains the most frequently used intervention world-wide. It is, however, recognized that, for certain
groups of patients, surgery may be technically very diffi-cult, may produce particularly unpredictable results, ormay be contraindicated on medical grounds. For thesepatients, nonsurgical options have been sought.
Botulinum toxin was first used in the treatment ofstrabismus by Alan Scott in the mid-1970s, and its use asan alternative to surgery has been explored.1-6 Theneuromuscular blockade of botulinum toxin is, however,temporary, and it is traditionally thought that its clinicaleffect lasts approximately 3 months.7 The long-termmanagement of strabismus therefore requires multipleinjections over time.
Author affiliations: Moorfields Eye Hospital, London, United Kingdom.Submitted April 9, 2007.Revision accepted April 11, 2008.Published online September 16, 2008.Reprint requests: John P. Lee, FRCS, FRCP, FRCOphth, Moorfields Eye Hospital,
It is unusual for patients to receive more than 5 botuli-num toxin injections in the management of their strabis-mus with this technique. The authors of a previous reportdescribed the characteristics of those who have receivedmore than 8 botulinum toxin injections in the long-termmanagement of their strabismus at our institution.8 Wenow report on a smaller group of patients with strabismuswho have received 25 or more botulinum toxin injections.This group represents the longest course of botulinum toxintreatment of an ocular motility disorder published to date.
Methods and MaterialsA secure dBase4 database (dBase Inc, Vestal, NY) is kept of allbotulinum toxin injections performed at our institution. Withrare exceptions, the data have been entered by only 2 senior staffmembers ( JPL and GGA) to ensure consistency. For the pur-poses of investigation, long-term treatment was defined as havinghad 25 injections or more of botulinum toxin. The medicalrecords of those patients who met this criterion were examinedand cross-referenced with the database. The patient demograph-ics, diagnosis, injection details, outcome, and complications wererecorded. Approval for the study was provided by the Research
Volume 12 Number 6 / December 2008570 Gardner et al
From mid-1987 on, a dose of 2.5 units of Dysport (IpsenPharmaceuticals, Slough, UK) in 0.1 mL of normal saline wasused for all injections into an extraocular muscle. Injections wereperformed under a topical anesthetic in an outpatient clinic withelectromyographic monitoring with the use of a Medelec MS6amplifier/recorder (Medelec Ltd., Surrey, UK). A signal greaterthan 100 microV, with an adequate distribution of high fre-quency spikes, was accepted as indicating correct placement ofthe disposable hypodermic needle electrode (VIASYS Health-care, Surry, UK). Before 1987, either 312,936, or 1,560 �g of“Oculinum” botulinum toxin, supplied by the University of Wis-consin, was used in 0.1 mL of normal saline. Follow-up of allpatients was undertaken in the botulinum toxin clinic at ourinstitution up to discharge or failure to reattend. The interval offollow-up was at 1 to 2 weeks after the initial injection and thenat regular intervals until discharge or failure to reattend. Visualacuity was measured using a Snellen chart at 6 m. Binocular functionwas determined in free space using a combination of one or more ofthe following: Bagolini striated lenses, Worth’s 4-Dot apparatus,and stereopsis testing (Titmus or TNO methods). A synoptophorewas used where testing in free space was not possible. Questionablebinocular function was defined as inconsistent results or theability to superimpose two images without fusion.
Statistical MethodsWe compared sex, binocular function, site injected, diagnosis,and complications between the group who received 25 or morebotulinum toxin injections and those who received 24 or fewerinjections using the Fisher’s exact test. We compared the meanage, mean follow-up, and number of previous operations of thesegroups using an exact Mann-Whitney U test. To examine howthe angle of deviation varied over time, the initial deviation andthe last recorded deviation were compared with the Wilcoxonsigned-ranks test for the long-term group. This was performedseparately for esodeviations and exodeviations. In addition themean deviation of the first half of all visits was compared with themean deviation of the second half of all visits, also using theWilcoxon signed-ranks test separately for esodeviations and exo-deviations. For example, if a patient had received 40 injections,the analysis was between the first 20 and the second 20 injections.Because only one patient exhibited a vertical deviation, no sta-tistical analysis could be performed.
To examine how the interval between injections varied over
Table 1. Patient demographics and follow-up
Diagnosis �24 bot
Mean age at first injection( years) 37 [rangeSex Men 2942
Women 3Mean follow-up ( years) 1.2 [rangeMean number of injections 3 [range,Mean number of previous operations 1.0 [rangeBinocular function Not demo
DemonstrQuestiona
Shown is a comparison of the patient demographics and follow-up for those whofewer injections.
time, the mean interval observed in the first half of all visits was
compared with the mean interval observed in the second half ofall visits. For example, the first 20 presentations were comparedwith the last 20 presentations for someone who had been seen 40times. Both the mean interval groups satisfied Kolomogarov-Smirnov testing for normality ( p � 0.000 and p � 0.001, respec-tively) and F testing of equality of variance (alpha � 0.05), andpaired t-testing could be used in the evaluation, the only situationwhere parametric testing was possible.
ResultsBetween November 1982 and January 2006, 17,345 injec-tions were given to 6,412 patients. Fifty-seven patientsreceived 25 or more injections of botulinum toxin in thetreatment of their strabismus or oscillopsia, and 6,317received 24 or less. One patient in the group receiving 25or more injections and 37 in the group receiving 24 orfewer injections were excluded from the analysis becausethey had oscillopsia alone with no evidence of strabismus.
Patient Demographics and Follow-upThe patient characteristics of the 2 groups are indicated inTable 1. There was no statistically significant differencebetween the mean age ( p � 0.187) or gender distribution( p � 0.115) between the long-term group and thosewho had received 24 or fewer injections. The duration offollow-up was statistically different ( p � 0001), withfollow-up being longer in the long-term group. The distri-bution of the number of previous operations was also sta-tistically different between the groups, with the long-termgroup having undergone a greater number of previoussurgical procedures ( p � 0.001). Just more than threequarters (75.9%) of the patients who were treated in thebotulinum toxin clinic have received 3 or fewer injections(Figure 1).
Presenting SymptomsUnacceptable cosmesis alone was the presenting symptomin 35 patients (61.4%), whereas diplopia alone was thecomplaint in 1 patient (1.8%). In an additional 18 patients(31.5%) from the long-term group, diplopia and unaccept-able cosmesis together were the main reason for attending.In 3 patients (5.3%), the reason for presentation was un-
toxin injections �25 botulinum toxin injections
3] 39 [range, 15 to 80]) Men 20 (35.1%)
.4%) Women 37 (64.9%)to 24.3] 11.95 [range, 3 to 22]] 34 [range, 25 to 68]] 1.8 [range, 0 to 5]
e 3537 (56.0%) Not demonstrable 49 (86.0%)88 (26.7%) Demonstrable 6 (10.5%)2 (17.3%) Questionable 2 (3.5%)
ceived 25 or more botulinum toxin injections and those who have received 24 or
ulinum
, 1 to 9(46.6%
375 (53, 0.040 to 24, 0 to 9nstrablable 16ble 109
have re
acceptable cosmesis and discomfort combined.
Journal of AAPOS
Volume 12 Number 6 / December 2008 Gardner et al 571
DiagnosisThe diagnostic grouping is indicated in Table 2. In bothgroups, the most frequently recorded diagnosis was con-secutive exotropia; however, the distribution of the various
FIG 1. A frequency histogram of the total number of botulinum toxininjections given per patient for all patients in the database.
Shown is a comparison of the diagnostic grouping for patients who have received25 or more botulinum toxin injections and those who have received 24 or fewerinjections.
underlying diagnoses was significantly different between
Journal of AAPOS
the long-term group and those who had received 24 orfewer injections ( p � 0.001).
Referral SourceFourteen patients, 24.6% of those treated long-term withbotulinum toxin, were referred directly to the toxin clinicat our institute by external strabismologists. A further 4patients (7.0%) were referred directly to the toxin clinic bynonstrabismologists at our institution. Thirty-five patients(59.6%) were referred to the toxin clinic by strabismolo-gists at our institution and for 5 patients (8.8%) the refer-ral source could not be determined.
Visual ParametersThe visual acuities in the noninjected eye was equal to orbetter than 6/18 (20/60) Snellen in all patients, except onein whom the vision was 2/60 (approx 6/200). The visualacuities in the injected eye were more widely distributedthan those seen in the nondeviated eye, ranging from noperception of light to 6/4 with a bias toward the pooreracuities. A greater proportion of the long-term group hadno demonstrable binocular function when compared withthose who received 24 or fewer injections (Table 1). Thisdifference was statistically significant ( p � 0.001).
Initial DeviationThirty-nine patients (68.4%) presented with an exodevia-tion with a mean angle of 44� (range, 4-90�). Seventeenpatients (29.8%) presented with an esodeviation with amean angle of 44� (range, 18-90�). One patient (1.8%)presented with a hypotropia measuring 50�.
Site InjectedIn patients with exotropia, a single lateral rectus musclewas injected, except for 3 patients (5.3%) in the long-termgroup and 58 patients (0.9%) in the group receiving 24 orfewer injections, where both lateral rectus muscles wereinjected. In those with esotropia, a single medial rectusmuscle was injected, except for 52 patients (0.8%) in thegroup receiving 24 or fewer injections, where both medialrectus muscles were injected. In the long-term group, 1patient received injections in the inferior rectus muscle(1.8%). In those receiving 24 or fewer injections, an infe-rior rectus muscle was injected in 300 patients (4.7%), aninferior oblique muscle was injected in 12 patients (0.2%),a superior rectus muscle was injected in 6 patients (0.09%),and a superior oblique muscle was injected in 1 patient(0.02%). The site injected in the 2 groups was not statis-tically different ( p � 0.124).
Continued ManagementFifty-two patients (91.2%) from the long-term group con-tinue to receive botulinum toxin for the management oftheir strabismus. Two patients (3.6%) went on to undergosurgery after receiving 25 or more injections of botulinum
toxin. Of this group, 1 patient was symptom free after a
Volume 12 Number 6 / December 2008572 Gardner et al
year and was discharged. This patient has a small-angleprimary exotropia (8� before the first injection) and feltthat, after 40 injections, they were no longer working forher and requested surgery. In fact, neither the intervalbetween injections had decreased nor the deviating angleincreased in the year before surgery. The other patientreturned to receiving botulinum toxin injections as theresult of a recurrent deviation. She had undergone 5 pre-vious surgical procedures, involving both eyes. A further 2patients (3.6%) were receiving ongoing injections but arenow deceased. One patient (1.8%) was discharged symp-tom free, after 25 or more injections, after at least a year offollow-up at age 44. Her diagnosis was a small angledresidual esotropia (20�) after one previous strabismus pro-cedure. Her angle gradually reduced and was less than 10�
for 3 years before discharge. An additional patient (1.8%)decided not to proceed with further botulinum toxin after34 injections at age 72. He had a secondary exotropia aftera retinal detachment. He had undergone 2 previous stra-bismus surgeries.
Angle of Deviation over TimeThe angle of deviation was observed to decrease over timein most patients. In those patients who had an esotropia atpresentation, the mean deviation decreased from 44� justbefore their first injection to 26� at the most recentlyrecorded visit ( p � 0.001). In those patients presentingwith an exotropia, the mean deviation decreased from 44�
just before their first injection to 24� at the most recentlyrecorded visit ( p � 0.001). The angle of deviation in thepatient who presented with a hypotropia decreased from50� just before the first injection to 9� at the most recentlyrecorded visit. The patient with oscillopsia remained or-thotropic throughout. These trends can also be seen dia-grammatically when the initial deviation and the mostrecently recorded deviation for each patient are compared(Figure 2). No patients had received a botulinum toxin
FIG 2. Comparison of the angle of deviation just before the first botulinumtoxin injection with the last recorded angle of deviation for those who havereceived 25 or more botulinum toxin injections.
injection in the two months prior to their most recent visit.
The mean deviation of the first half of all visits for thosewith an esotropia was 29� (SD 16.8). The mean esodevia-tion of the second half of all visits for the same group was22� (SD 23.0). The values for the second half were signif-icantly different from those in the first half ( p � 0.027).The mean deviation of the first half of all visits for thosewith an exotropia was 27� (SD 13.6). The mean esodevia-tion of the second half of all visits for the same group was19� (SD 14.5). The values for the second half were signif-icantly different from those in the first half ( p � 0.001).The variation in the angle of deviation over time for atypical patient can be seen in Figure 3.
Interval Between Injections over TimeThe interval between injections was found to increaseover time in most patients. The mean interval betweeninjections was 4.9 months (SD, 5.3). In the first half of allvisits, the average interval between injections was 4.1months (SD 2.2), and in the last half of all visits the meanwas 5.7 months (SD 2.6). This difference was statisticallydifferent ( p � 0.001, SD 3.4). This pattern can also beseen graphically when comparing the average interval be-tween injections in the first year to the average intervalbetween injections in the last year (or the time between thelast two injections, if this was more than 1 year; Figure 4).The variation in the injection interval over time for atypical patient can also be seen in Figure 3.
ComplicationsThe distribution of complications is indicated in Table 3.The differences between the long-term group and thegroup that had received equal to or fewer than 24 injec-tions were not statistically significant ( p � 0.688).
CostThe direct cost of each botulinum toxin injection wascalculated as £71($140) (including outpatient visit, botuli-num toxin, and disposable electrode costs). The cost oftreatment based on a mean injection number of 34 is,
FIG 3. Variation of the angle of deviation recorded just before eachbotulinum toxin injection over time for one of the patients who hasreceived 25 or more botulinum toxin injections.
therefore, £2414($4760). A mean number of 17 days off
Journal of AAPOS
Volume 12 Number 6 / December 2008 Gardner et al 573
work was also required in the course of this treatment. Incomparison, the mean direct cost of definitive early sur-gery with one operation is £952($1895) (including 2 fol-low-up appointments). A mean number of 7 days off workis required for those who undergo strabismus surgery atour institution. A direct cost comparison between thetreatments is not possible at our institution as a bias existsgiven that we are known to be a referral center for botu-linum toxin use in the United Kingdom, and we have ahigh proportion of patients with multiple previous surger-ies, poor binocularity, or who are thought not medically fitfor a general anesthetic.
DiscussionIn the mid-1970s, reports of the use of botulinum toxin inthe assessment and treatment of strabismus began emerg-ing.9 It has become evident over time that botulinum toxinmay be used in the longer-term management of strabis-
FIG 4. Comparison of the mean interval between each botulinum toxininjection in the first year and the mean interval between each botulinumtoxin injection in the last year (or the time between the last t2 injections,if this was more than 1 year) for those who have received 25 or morebotulinum toxin injections.
Shown is a comparison of the complications of treatment recorded for those whohave received 25 or more botulinum toxin injections and those who have received24 or fewer injections.
mus.8,10 A number of patients may not be suitable for
Journal of AAPOS
surgery because of the high likelihood of failure/compli-cations or because surgery is contraindicated on medicalgrounds. Although surgery under local anesthetic may beoffered, this is, in our experience, often declined particu-larly when botulinum toxin injections are offered as analternative.
As has been reported before, it is our experience that thelong-term use of botulinum toxin in the management ofocular motility disorders is largely patient driven.8 Itshould be noted, however, that given the extensive expe-rience of using botulinum toxin in the management ofstrabismus and oscillopsia at our institution, a clinical biastoward offering this method of treatment may be evident.The long-term group was found to have had a greaternumber of previous operations, poorer visual acuity in thedeviated eye, and a lower proportion with binocular visionwhen compared with those who received 24 or fewerinjections, but this difference may represent a bias towardthese patients being offered botulinum toxin in preferenceto surgery. The distribution of the underlying diagnosesbeing different in the 2 groups may also represent clinicalbias. For example, the greater proportion of restrictivestrabismus and in particular post retinal detachment stra-bismus being seen in those in the long-term group (10.5%)compared with those having received 24 or fewer injec-tions (5.2%). A quarter of the long-term group was, how-ever, referred directly to the botulinum toxin clinic formanagement from external ophthalmologists, whichwould tend to reduce bias per se.
Continued ManagementIt is interesting that 2 patients, having previously refusedfurther surgical corrective procedure, went on to undergosurgery after 25 injections of botulinum toxin. It was alsointeresting that a patient declined further procedures afterreceiving 36 previous injections. In all three cases chang-ing social situation was the precipitant.
Increase in the Injection Interval and Decreasein the Angle of Deviation Over TimeIt has been traditional dogma that botulinum toxin injec-tions are only clinically effective for approximately 3months and that this does not change over time. It has,however, been previously reported that the interval be-tween injections tended to increase with time in mostpatients and this was also seen in this study.8 This could bethat either the effect is lasting longer or that patientschoose a longer period after the injection has worn offbefore re-presenting for a subsequent injection. Horganet al8 have indicated that the former was more likely intheir previous review. The angle of deviation was alsonoted to decrease in many over time, although a contin-uous reproducible reduction prior to each reinjection wasnot seen.
The physiological mechanisms underlying these
changes are unclear. The published evidence suggests that
Volume 12 Number 6 / December 2008574 Gardner et al
atrophy of the fibers is an unlikely cause, as it has not beenseen in extraocular muscles post botulinum toxin to asignificant degree.11,12 Some have reported an increase inmuscle fiber size in orbital singly innervated fibers, whichare involved in saccadic initiation.13,14 There is evidence ofultrastructural changes in extraocular muscles after botu-linum toxin injection, particularly involving an increasedamount of satellite cells and changes in the nature of themyosin heavy chains.12,14 In addition, the changes in sar-comere length seen after surgery may also play a role postrepeated botulinum toxin injection but this has not beenexamined to date.15
CostThe direct cost of the long-term management of strabis-mus using botulinum toxin is approximately 2.5 times thatof definitive early surgery with one operation, if the effectof surgery is assumed to last at least as long as the meanduration of botulinum toxin treatment (12.05 years). It isreasonable to conclude that it is very unlikely that onefurther operation alone would provide long-term accept-able alignment in this group of patients, and, with 2.5operations over a mean of 12 years, the costs of botulinuminjection and surgery are identical. It should be noted,however, that the group undergoing long-term botulinumtoxin treatment at our institution had either refused orwere thought not suitable for further surgical treatment. Aformal patient satisfaction survey has not yet been per-formed on this group, but in all cases the patient medicalrecords note that the patients were happy with the ongo-ing botulinum toxin treatment. In the United Kingdom itis possible to provide botulinum toxin for these patientswhere no real alternative exists, but this may not be so inall health care systems.
ComplicationsThere was not a greater incidence of complications in thelong-term group when compared with those who hadreceived 24 or fewer injections. The most common com-plications were transient ptosis and an induced verticaldeviation. These usually resolve quicker than the reducedfunction of the injected muscle, presumably due to theconcentration of the over spilled toxin being less. Althoughantibodies to botulinum toxin were not investigated formally,there was no evidence of a decreased effect over time. Thissuggested that, even if present, their effect was not clini-cally significant in the long-term group studied.
Future StrategiesDespite finding that the angle tends to decrease and thatthe interval between injections tends to increase over time,the long-term treatment of strabismus with botulinumtoxin requires multiple ongoing injections. A pharmaco-logical compound with a longer lasting effect would bevery desirable. Some progress has been made in this area
using insulin-like growth factor-1,16 ricin-mAb35,17 and
bupivacaine.18 However, the clinical effect of bupivacaineand insulin-like growth factor-1 is the opposite of botuli-num toxin in that it produces an increased action in theinjected muscle by inducing hypertrophy. Following aninjection of bupivacaine into a right lateral rectus musclein the treatment of a 14� residual esotropia, stability of theresultant 4� esophoria has been seen up to 540 days postinjection (Alan Scott, personal communication, 2008).
Although for many patients surgery remains the mostreasonable option for the long-term management of theirocular motility disorder, botulinum toxin currently repre-sents a safe alternative. It is particularly suited to those inwhom surgery is not possible on medical grounds, thosewhere surgery may be technically very difficult, thosewhere the results of surgery may be particularly unpredict-able, or for those that would prefer toxin injections oversurgery. The effect that the interval between injectionstends to increase over time may be particularly appealingto patients who plan to embark on such treatment.
Literature SearchA literature search was performed using OVID/MEDLINE and Experpta Medica/EMBASE databases upto and including April 9, 2007, using the following searchheadings: botulinum toxin, oculinum, Botox™, Dysport™, oc-ular motility, strabismus, nystagmus, oscillopsia, diplopia, andextraocular muscle(s). No restrictions were placed on thelanguage of the article during the search.
References1. Tejedor J, Rodriguez JM. Early retreatment of infantile esotropia:
Comparison of reoperation and botulinum toxin. Br J Ophthalmol1999;83:783-87.
2. Dawson EL, Lee JP. Does Botulinum toxin have a role in thetreatment of small-angle esotropia? Strabismus 2004;12:257-60.
3. Dawson EL, Marshman WE, Adams GG. The role of botulinumtoxin A in acute-onset esotropia. Ophthalmology 1999;106:1727-30.
4. Dawson EL, Sainani A, Lee JP. Does botulinum toxin have a role inthe treatment of secondary strabismus? Strabismus 2005;13:71-73.
5. Ing MR. Botulinum alignment for congenital esotropia. Ophthal-mology 1993;100:318-22.
6. Repka MX, Lam GC, Morrison NA. The efficacy of botulinum neu-rotoxin A for the treatment of complete and partially recovered chronicsixth nerve palsy. J Pediatr Ophthalmol Strabismus 1994; 31:79-84.
8. Horgan SE, Lee JP, Bunce C. The long-term use of botulinum toxinfor adult strabismus. J Pediatr Ophthalmol Strabismus 1998;35:9-16.
9. Scott AB, Rosenbaum A, Collins CC. Pharmacologic weakening ofextraocular muscles. Invest Ophthalmol 1973;12:924-7.
10. Lawson JM, Kousoulides L, Lee JP. Long-term results of botulinumtoxin in consecutive and secondary exotropia: Outcome in patientsinitially treated with botulinum toxin. J AAPOS 1998;2:195-200.
11. Ohtsuki H, Hasebe S, Okano M, Furuse T. Morphological changesin the orbital surface layer muscle of the rabbit eye produced bybotulinum toxin. Ophthalmologica 1998;212:53-60.
12. Kranjc BS, Sketelj J, D’Albis A, Erzen I. Long-term changes inmyosin heavy chain composition after botulinum toxin a injectioninto rat medial rectus muscle. Invest Ophthalmol Vis Sci 2001;42:
3158-64.
Journal of AAPOS
Volume 12 Number 6 / December 2008 Gardner et al 575
16. McLoon LK, Anderson BC, Christiansen SP. Increasing muscle strengthas a treatment for strabismus: Sustained release of insulin-like growthfactor-1 in rabbit extraocular muscle. J AAPOS 2006;10:424-429.
17. McLoon LK, Christiansen SP. Increasing extraocular musclestrength with insulin-like growth factor II. Invest Ophthalmol VisSci 2003;44:3866-72.
18. Scott AB, Alexander DE, Miller JM. Bupivacaine injection of eye
muscles to treat strabismus. Br J Ophthalmol 2007;91:146-8.
An Eye on the Arts – The Arts on the Eye
Ode on a Lazy Eye
It allows me to be evasive,wandering with the one,while the other eye, staringat your forehead, unnervesbecause you do not knowin which window to peer.But it’s not up to you.I switch at willfrom one eye’s viewto the other.Or combine the two perspectivesfor a deconstructive image,the world a Cubist canvas.Wall-eyes can be claustrophobic,and the restive stragglerwill eventually stray more freakishly off-trackin search of some transcendence.Where else to go but in?Eyeball rolling backto the unfolding inner skullclose-up on the machinations of vision.You may be alarmedby this unseemly introspection,and accuse me of having a fit.Don’t worry,as long as I eschew the three-dimensionalworld produced by two eyesdiverging a mere centimetre,and exist alonga kaleidoscopic horizonof infinite vanishing points,fit is something I’ll never do.
