Various anticholinergic drugs can induce pupilary dilation.In children, topical anticholinergic drugs transitoryincrease the accommodative convergence toaccommodation ratio and exacerbate underlying esotropia[1].

Different anticholinergic drugs have been reported asinducing diplopia and/or esotropia as: haloperidoland benztropine mesylate, oxybutynin [2, 3].

Tricyclic antidepressants (TCAs) decrease the amountof time spent in REM sleep, stimulate vasopressin secretion,and relax the detrusor muscle. Given the efficacyand safety of enuresis alarms and desmopresin,tricyclic antidepressants which are anticholinergic substances(eg, imipramine, amitriptyline and de sipra -mine) are a third-line treatment for monosymptomaticenuresis (eg, children who have failed alarm thera -py and/or desmopressin) [4]. In several country theyare although used as a first line treatment.

Case Report

We report the case of 9 years old child who was referto us for intermittent exotropia of the right eye. The XTonset according to the parents was the age 6 months.

He was treated with prism glasses. No other treatmentshave been used.Surgery was proposed but initially parents refused it.

The first examination was done in our clinic in June2012 and revealed:VA OD=0, 9 with -1, 50 cyl ax 180; VAOS=0, 8 with +1,50 cyl ax 90; 5 PD base-in were included in each lensof his glasses.

Fusion at distance was intermittently present with bettercontrol at near (Figure 1).

Re-evaluation was done 3 months and 9 months laterafter prisms-in removal and new correction prescriptionaccording to cycloplegic (cyclopentolate 1%)measurements.

Maximum deviation found at distance and near was:-35 PD in primary position, -40 PD in up-gaze, -30 PDin down-gaze. Good adduction and acceptable convergenceamplitude on both eyes were present.

The surgical treatment was provided in June 2013: ODRight Lateral Rectus Muscle Recession 8 mm and OSLeft Lateral Muscle Recession 7, 5 mm.

Two months postop, in August 2013 the patient had a+4 PD esophoria in primary position with stable fusionpresent at near and distance and 40’’ Stereopsis atnear and stereopsis present at distance (Figure 2).

In November 2013 (emergency request), the clinicalexamination found permanent diplopia accompanyingan esotropia of +18 PD at distance and near,larger in down-gaze, +22 PD and smaller in up-gaze:+12 PD. The patient had torticolis using a down-chinposition in order to avoid diplopia. The fusion was possiblewith 20PD base-out.

The patient presented alsodilated pupils, difficulties in reading caused by reducedaccommodation amplitude and also problemsin concentration at school.

The diplopia onset was in September 2013 as intermittentdiplopia and became permanent in the lastmonth. In September the patient started a treatmentwith Amitriptyline for nocturnal enuresis.

We suspectedto deal with a side effect of the Amitriptyline.For themoment Fresnel foils were recommended and a detailedletter was send to the Neurologist.

The anticholinergic medication was stopped by theNeurologist in December 2013. The esotropic angledecreased in time after medication cessation.In May 2014, we found 8 PD ET at near and distance(+2 PD in up-gaze, +10 PD in down-gaze). Stable fusionwas possible with 6 PD BO included in glasses.

Comments

The reversibility of the anticholinergic medication sideeffect was not complete unfortunately at 6 months aftertreatment cessation, the remaining ET, larger thanthe previous one suggesting possible long-term effectsin certain patients.

Patients with anthicolinergic medication should becarefully followed especially when they have strabismushistory. Some patients are probably more susceptiblethan others in developing esotropia and diplopiaexplaining why only some patients develop diplopia.The susceptibility is probably connected with individualfactors but fusion vulnerability can be a possiblerisk factor confirming literature data [5, 6].

We report the case of a 9 years old child operated for intermittent exotropia and V-pattern witha good result 2 months after bilateral Lateral Rectus Muscle Recession. The binocular vision wasrestored in primary position and down-gaze with excellent stereopis at near and distance and adeviation of +4 PD in primary position. Three months later the patient develops a consecutiveesotropia of + 18 PD in primary position with diplopia in all gazes triggered by amitriptyline treatmentprescribed one month earlier for nocturnal enuresis. Six months after amitriptyline treatmentcessation the binocular vision was restored showing a transitory and reversible effect. Fusion vulnerabilitycan be a possible risk factor in developing diplopia and esotropia in patients treatedwith anticholinergic drugs.

1. Oh SY, Shin BS. Benztropine-induced esotropia andmydriasis. J Neuroophthalmol 2007; 27: 312–3.
2. Wong EYH, Harding A, Kowal L. Oxybutynin-associatedesotropia. AAPOS 2007; 11: 624–37
3. Kaneko K, Fujinaga S, Ohtomo Y, Shimizu T, YamashiroY. Combined Pharmacotherapy for nocturnal enuresis. PediatrNephrol 2001, Aug; 16(8): 662-4
4. von Noorden GK. Binocular Vision and Ocular Motility.Theory and Management of Strabismus. 5th St. Louis: CVMosby; 1996: 95–6.
5. Anderson JM, Brodsky MC. Anticholinergic Esotropia,Neuro-Ophthalmol, Vol. 28, No. 4, 2008: 359-360
6. Good VW, Crain LS. Esotropia in a Child Treated withScopolamine Patch for drooling. Pediatrics 97, 1, 1996:126–127.

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