Tonic Pupil Research Articles

A pupillometric investigation of state regulation in adults scoring high versus low on ADHD symptomatology

According to the state regulation deficit (SRD) account, ADHD is associated with difficulties regulating tonic arousal levels, which may be due to inefficient effort allocation. We aimed to test the SRD account by using a target detection task with three different event rates (ER; 700 ms, 1800 ms, 6000 ms), in order to manipulate the tonic arousal state and its effects on performance and pupil indices in adults with high (n = 40) versus low (n = 36) ADHD symptom levels. In an additional condition, a fast ER (700 ms) was accompanied by auditory white noise (WN), to further increase tonic arousal level. The ER manipulation had a clear effect on RT and variability of RT. These effects were more pronounced for the high-ADHD group, especially for variability of RT with decreasing ER, suggestive of deficient upregulation of a tonic arousal state in that group, in line with their self-reported SRDs in daily life. Adding WN to the fast condition led to more errors, however similarly for both groups. Contrary to our predictions, the ER manipulation had no effect on tonic pupil size (as a measure of tonic arousal). Phasic pupil amplitude (as a measure of cognitive effort) linearly increased with decreasing ER, suggesting more effort allocation during slower ERs. WN decreased phasic pupil amplitude, but had no impact on tonic pupil size. Importantly, however, no ADHD-related differences were present for the pupil indices. In conclusion, adults with elevated levels of ADHD symptoms reported more SRDs in daily life and showed a performance pattern that suggests difficulties in upregulating but not downregulating the tonic arousal state. Surprisingly, these findings were not accompanied by group differences in pupillometric indices. This casts some doubts on the relationship between these measures of autonomic nervous system activity and state regulation, in particular in the context of ADHD symptomatology.

Unilateral Adie’s Tonic Pupil after Coronavirus Disease-19 (COVID-19): A Case Report

Introduction: Adie’s tonic pupil is a neuro ophthalmological disorder characterized by dilated pupil, which is unresponsive to light. It is caused by damage to postganglionic fibers of the parasympathetic innervation of the eye. Recent events of the coronavirus disease 2019 (COVID-19) pandemic had suggested that severe acute respiratory syndrome coronavirus-2 infection (SARS-CoV-2) had neurotropic and neuroinvasive capabilities. Purpose: To report a rare case of unilateral Adie’s tonic pupil after COVID-19. Methods: A single case report study. Case Report: A 31-year-old woman presented with a glare on the right eye 3 months ago. No other symptom was reported. No prior history of using any eye drops and trauma. Further investigation revealed a history of asymptomatic SARS CoV-2 infection. Her best-corrected visual acuity of both eyes was 1.0, but we observed an impairment of accommodation on the right eye. A fixed dilated right pupil, 8 mm in diameter, was observed without any constriction on near reflex. Slit lamp and funduscopy examination were within normal limits on both eyes. Pilocarpine 0.1% test was positive on the right eye. Neurological examinations and brain imaging was within normal limits. The patient was diagnosed with Adie’s tonic pupil. She was treated with pilocarpine 0.1% once daily. After 2 months of follow up, her complaint of glare was diminished but no improvement of near acuity was seen on the right eye. Conclusions: This case report was one of the first few cases of Adie’s tonic pupil possibly associated with COVID-19.

Zoom behavior during visual search modulates pupil diameter and reflects adaptive control states.

Adaptive gain theory proposes that the dynamic shifts between exploration and exploitation control states are modulated by the locus coeruleus-norepinephrine system and reflected in tonic and phasic pupil diameter. This study tested predictions of this theory in the context of a societally important visual search task: the review and interpretation of digital whole slide images of breast biopsies by physicians (pathologists). As these medical images are searched, pathologists encounter difficult visual features and intermittently zoom in to examine features of interest. We propose that tonic and phasic pupil diameter changes during image review may correspond to perceived difficulty and dynamic shifts between exploration and exploitation control states. To examine this possibility, we monitored visual search behavior and tonic and phasic pupil diameter while pathologists (N = 89) interpreted 14 digital images of breast biopsy tissue (1,246 total images reviewed). After viewing the images, pathologists provided a diagnosis and rated the level of difficulty of the image. Analyses of tonic pupil diameter examined whether pupil dilation was associated with pathologists' difficulty ratings, diagnostic accuracy, and experience level. To examine phasic pupil diameter, we parsed continuous visual search data into discrete zoom-in and zoom-out events, including shifts from low to high magnification (e.g., 1× to 10×) and the reverse. Analyses examined whether zoom-in and zoom-out events were associated with phasic pupil diameter change. Results demonstrated that tonic pupil diameter was associated with image difficulty ratings and zoom level, and phasic pupil diameter showed constriction upon zoom-in events, and dilation immediately preceding a zoom-out event. Results are interpreted in the context of adaptive gain theory, information gain theory, and the monitoring and assessment of physicians' diagnostic interpretive processes.

Neuro-ophthalmic Manifestations of Coronavirus Disease 2019 and Its Vaccination: A Narrative Review.

Coronavirus disease 2019 (COVID-19) is a current pandemic caused by SARS-CoV-2 that has vastly affected the whole world. Although respiratory disease is the most common manifestation of COVID-19, the virus can affect multiple organs. Neurotropic aspects of the virus are increasingly unfolding, in so far as some respiratory failures are attributed to brainstem involvement. The neuro-ophthalmic manifestations of COVID-19 and the neuro-ophthalmic side effects of vaccination were reviewed. The major findings are that the SARS-CoV-2 infection commonly causes headaches and ocular pain. It can affect the afferent and efferent visual pathways by ischemic or inflammatory mechanisms. Optic nerve may be the origin of transient or permanent visual loss from papillophlebitis, idiopathic intracranial hypertension, or optic neuritis. Cerebrovascular strokes are not uncommon and may lead to cortical visual impairment or optic nerve infarction. SARS-CoV-2 may affect the pupillomotor pathways, resulting in tonic pupil (Adie's syndrome) or Horner's syndrome. Cranial neuropathies including third, fourth, sixth, and seventh nerve palsies have all been reported. Rhino-orbital mucormycosis superinfections in COVID-19 patients receiving steroids or other immunosuppressive therapies may result in unilateral or bilateral visual loss and ophthalmoplegia. Autoimmune conditions such as Guillain-Barré, Miller-Fisher syndrome, and ocular myasthenia have been reported.

Autoimmune Encephalitis With Ganglionic a3-AChR Antibodies

Objective To describe a case of autoimmune encephalitis presented as new onset refractory nonconvulsive status epilepticus and autonomic failure caused by alpha-3 ganglionic acetylcholine receptor autoantibodies (a3-AChR Ab). Background Autoimmune autonomic ganglionopathy (AAG) is rare acquired dysautonomia in adults due to a3-AChR Ab. A patient typically presents with subacute autonomic dysfunction, and encephalitis has not been reported yet. Design/Methods NA. Results A 60 years old female presented with progressive worsening of mental status for two weeks. Vital signs were normal. The patient was somnolent, nonverbal, with tonic non-reactive pupils on the exam. CT head showed multiple subcortical hypodensities. MRI brain demonstrated T2-FLAIR hyperintense lesions in bifrontal lobes sparing the U-fibers, with abnormal leptomeningeal/pial perivenular type enhancement. MRI C/T spine, CT chest/Abd/pelvis were negative. Although serum and CSF testing showed inflammatory markers, meningoencephalitis and autoimmune encephalitis panel were negative, except for the serum Paraneoplastic panel was positive with high titer a3-AChR Abs. EEG showed nonconvulsive status epilepticus, which required management with three antiseizure medications. Initially, the patient had little response to empirical pulse methylprednisolone therapy. Later showed good clinical response with plasmapheresis. Later on she presented with nonobstructive small bowel obstruction, resolved with another pulse steroid therapy, discharged on dexamethasone taper. On a three-month follow-up, the patient was in near clinical remission, supported with resolved lesions on a repeat MRI. She never relapsed after two years of follow-up. Conclusions Studies have shown that a3-AChR Abs can result in diverse neurological manifestations, mainly dysautonomia. Our patient presented with encephalitis, dysautonomia, and refractory nonconvulsive status epilepticus. Scans suggested diffuse leukoencephalopathy, patient was found to have high 3-ACHR antibody seropositivity. Initially, the patient was steroid-resistant but showed clinical improvement with plasmapheresis. We have described an interesting case of encephalitis likely associated with a3-AChR Ab that has not been previously described. More studies are required to confirm this association.

Benign food-borne type B botulism presenting as unilateral internal ophthalmoplegia: a case report

BackgroundFood-borne botulism is a rare neuromuscular junction disorder due to the effect of toxins released from Clostridium botulinum ingested by eating improperly stored food. Its classic manifestation is a rapidly evolving descending symmetrical flaccid paralysis with dysautonomia.Case presentationWe have described a case of type B food-borne botulism with a benign clinical course characterized by an initially unilateral tonic mydriatic pupil. An extensive neurophysiological evaluation inclusive of pilocarpine eye drop(s) test, facial and limbs nerve stimulation and sudomotor tests, was decisively leading the diagnostic process.ConclusionsThe importance of what has been described here lies in underlining that it is always advisable to consider food-borne botulinum intoxication, even in the case of unilateral/asymmetrical internal ophthalmoplegia without generalized progressive involvement of the voluntary muscles.

Measures of tonic and phasic activity of the locus coeruleus-norepinephrine system in children with autism spectrum disorder: An event-related potential and pupillometry study.

A growing body of research suggests that locus coeruleus-norepinephrine (LC-NE) system may function differently in individuals with autism spectrum disorder (ASD). Understanding the dynamics of both tonic (resting pupil diameter) and phasic (pupil dilation response [PDR] and event-related potential [ERP]) indices may provide meaningful insights about the nature of LC-NE function in ASD. Twenty-four children with ASD and 27 age- and nonverbal-IQ matched typically developing (TD) children completed two experiments: (1) a resting eye-trackingtaskto measure tonic pupil diameter, and (2) a three-stimulus oddball paradigm to measure phasic responsivity using PDR and ERP. Consistent with prior reports, our results indicate that children with ASD exhibit increased tonic (resting pupil diameter) and reduced phasic (PDR and ERP) activity of the LC-NE system compared to their TD peers. For both groups, decreased phasic responsivity was associated with increased resting pupil diameter. Lastly, tonic and phasic LC-NE indices were primarily related to measures of attention-deficit/hyperactivity disorder (ADHD), and not ASD, symptomatology. These findings expand our understanding of neurophysiological differences present in ASD and demonstrate that aberrant LC-NE activation may be associated with atypical arousal and decreased responsivity to behaviorally-relevant information in ASD.

Fatigue and Arousal Modulations Revealed by Saccade and Pupil Dynamics.

Saccadic eye movements are directed to the objects of interests and enable high-resolution visual images in the exploration of the visual world. There is a trial-to-trial variation in saccade dynamics even in a simple task, possibly attributed to arousal fluctuations. Previous studies have showed that an increase of fatigue level over time, also known as time-on-task, can be revealed by saccade peak velocity. In addition, pupil size, controlled by the autonomic nervous system, has long been used as an arousal index. However, limited research has been done with regards to the relation between pupil size and saccade behavior in the context of trial-to-trial variation. To investigate fatigue and arousal effects on saccadic and pupillary responses, we used bright and emotional stimuli to evoke pupillary responses in tasks requiring reactive and voluntary saccade generation. Decreased voluntary saccade peak velocities, reduced tonic pupil size and phasic pupillary responses were observed as time-on-task increased. Moreover, tonic pupil size affected saccade latency and dynamics, with steeper saccade main sequence slope as tonic pupil size increased. In summary, saccade dynamics and tonic pupil size were sensitive to fatigue and arousal level, together providing valuable information for the understanding of human behavior.

Intervention of Adie's tonic pupil with iris tinted contact lenses with clear pupil - Case report

We report the optometric management of a 27-year-old female diagnosed with Adie's tonic pupil who was otherwise systemically stable. This case report is an effort to understand how tonic pupil management with iris tinted clear pupil contact lenses helps to resolve quantitative and qualitative visual disturbances similar to pharmacological treatment (diluted pilocarpine). The case report shows that it is an effective alternative management to overcome visual symptoms for patients with Adie's tonic pupil compared to pilocarpine (0.1%).

Pupillary Abnormalities After Excision of Orbital Cavernous Venous Malformations.

The aim of this study was to determine the incidence and recovery rate for pupillary abnormalities after excision of orbital cavernous venous malformations (OCVMs). Retrospective case-note and imaging review for patients with OCVMs, with an estimation of odds ratios (ORs) in relation to the position of the mass and surgical approach. The 287 included patients (176 female; 61%) presented at a mean age of 46.5 years: 243/287 (85%) OCVMs were intraconal, 253/287 (88%) located in the posterior two-thirds of the orbit, and 29/287 (11%) wedged tightly in the apex. Pupillary changes-varying from minor sectoral paresis (only evident on slit-lamp examination) to a marked mydriasis-were noted in 21% (60/287) of patients and were strongly associated with removal of intraconal (60/243 [25%]; p < 0.001), apical (14/29 [48%]; OR, 4.3; p < 0.001), inferior or inferotemporal (41/105 [39%]; OR, 5.5; p < 0.001) masses. Lateral approaches-either with (23/129; 18%) or without (30/71; 42%) osteotomy-were associated with 88% (53/60) of all abnormalities (OR, 4.1; p < 0.001). Where known, the abnormalities improved in 43/50 (86%), although 15/43 (35%) had a persistent tonic pupil. Pupillary abnormalities after excision of OCVMs can occur in up to a quarter of intraconal lesions-particularly those located inferotemporally or inferiorly-and in about a half of apical lesions. Lateral or inferolateral orbital approaches that disrupt the inferior intraconal fat appear to be associated with a higher risk. Most changes resolve or improve markedly, although a third of those affected may have a persistent tonic pupil.

Paraneoplastic syndromes in ophthalmology

Paraneoplastic syndromes consist on systemic manifestations associated with certain cancers which are not a direct consequence of tumor invasion or its metastases. It is known that autoimmunity and autoantibody synthesis play an important role in its pathophysiology due to a process of molecular mimicry. Paraneoplastic syndromes in ophthalmology are rare, but it is important to recognize them clinically because in some cases symptoms preceded the diagnosis of an underlying neoplasia. Most frequently involved cancer is small cell lung carcinoma, but there is also a relationship with other tumor etiologies such as thymoma, gynecological tumors or neuroblastoma in children. Paraneoplastic syndromes with ocular involvement can be divided into those that affect the afferent visual pathway, such as cancer-associated retinopathy, melanoma-associated retinopathy, or paraneoplastic optic neuropathy; and the ones that affect the efferent visual pathway, such as bilateral tonic pupils, Myasthenia Gravis, Lambert-Eaton syndrome or paraneoplastic cerebellar degeneration. The presence of autoantibodies is helpful in clinical practice but negativity does not exclude this diagnosis. Although evolution and prognosis is linked to primary disease, in some cases specific treatment, usually immunosuppressive therapy, can help improving patients quality of life.

Water and Meadow Views Both Afford Perceived but Not Performance-Based Attention Restoration: Results From Two Experimental Studies

Attention Restoration Theory proposes that exposure to natural environments helps to restore attention. For sustained attention—the ongoing application of focus to a task, the effect appears to be modest, and the underlying mechanisms of attention restoration remain unclear. Exposure to nature may improve attention performance through many means: modulation of alertness and one’s connection to nature were investigated here, in two separate studies. In both studies, participants performed the Sustained Attention to Response Task (SART) before and immediately after viewing a meadow, ocean, or urban image for 40 s, and then completed the Perceived Restorativeness Scale. In Study 1 (n = 68), an eye-tracker recorded the participants’ tonic pupil diameter during the SARTs, providing a measure of alertness. In Study 2 (n = 186), the effects of connectedness to nature on SART performance and perceived restoration were studied. In both studies, the image viewed was not associated with participants’ sustained attention performance; both nature images were perceived as equally restorative, and more restorative than the urban image. The image viewed was not associated with changes in alertness. Connectedness to nature was not associated with sustained attention performance, but it did moderate the relation between viewing the natural images and perceived restorativeness; participants reporting a higher connection to nature also reported feeling more restored after viewing the nature, but not the urban, images. Dissociation was found between the physiological and behavioral measures and the perceived restorativeness of the images. The results suggest that restoration associated with nature exposure is not associated with modulation of alertness but is associated with connectedness with nature.

Isolated Adie Pupil Associated With Anti-CASPR2 Antibodies

Isolated Adie Pupil Associated With Anti-CASPR2 Antibodies

360-Degree laser retinopexy in primary vitrectomy for rhegmatogenous retinal detachment: factors associated with its use and impact on surgical outcomes

BackgroundTo determine patient and surgical factors associated with the use of 360-degree laser retinopexy during primary pars plana vitrectomy (PPV) ± scleral buckle (SB) for rhegmatogenous retinal detachment (RRD) and its impact on surgical outcomes.MethodsPatients who underwent PPV ± SB for repair of non-complex RRD at a single centre were included in this retrospective study. The primary outcome was single surgery anatomical success (SSAS). Secondary outcomes included visual acuity, epiretinal membrane formation, the presence of cystoid macular oedema, tonic pupil and corneal epithelial defects. Multiple logistic regression and multivariate regression was used.ResultsThe study included 192 cases, of which 130 received 360-degree laser. Worse preoperative logMAR visual acuity (P = 0.009), male sex (P = 0.060), higher PVR grades, supplemental SB (P = 0.0468) and silicone oil/C3F8 tamponade (P < 0.0001) were associated with 360-degree laser use. No significant associations between 360-degree laser and SSAS (P = 0.079), final logMAR visual acuity (P = 0.0623), ERM development (P = 0.8208), postoperative CMO (P = 0.5946), tonic pupil (P > 0.9999) or corneal epithelial defects (P = N/A) were found.Conclusions360-degree laser retinopexy during primary PPV ± SB for RRD was associated with more complex cases and more extensive operations. Even when accounting for this, there was no difference in surgical outcomes or complication rates.

Photophobia as a Presenting Feature in Adie’s Tonic Pupil

A 34 years old female presented with complains of photophobia since 6-7 months. On examination, she had anisocoria of 4 mm in room light which increased in bright light. The left pupil was dilated and unresponsive to direct and indirect light stimuli. It did however, constrict slowly on near fixation followed by slow re-dilatation on distance fixation. A diagnosis of Adie’s tonic pupil was made since left pupil constricted with instillation of dilute pilocarpine 0.1%. Her symptoms of photophobia and blurred vision immediately resolved. Photochromatic glasses and dilute pilocarpine 0.1% three times a day were prescribed. Prompt symptomatic relief of photophobia and blurred vision was observed.

Ураження нервової системи в пацієнта із синдромом Еді (клінічний випадок)

Синдром Еді (Adie-Holmes), або синдром тонічної зіниці, — стан, що характеризується тріадою основних симптомів: одностороннім тонічним розширенням зіниці, парезом акомодації з відсутністю або значним зменшенням реакції зіниці на світло і зниженням сухожильних рефлексів. В основі захворювання лежить порушення функції парасимпатичної нервової системи. Синдром виникає внаслідок ураження циліарного ганглія, що забезпечує парасимпатичну іннервацію м’яза зіниці (m. sphincter pupillae), рогівки й оболонки очного яблука. Нерідко стан супроводжується порушенням функції спінальних гангліїв і, як наслідок, вегетативною дисфункцією у вигляді розладу потовиділення, зазвичай на одній стороні тіла, рідше — розладом серцевого ритму, лабільністю артеріального тиску. Частий супутник синдрому Еді — відсутність або зниження колінних рефлексів, рідше — ахіллових. Етіологія захворювання остаточно не з’ясована, не виключений бактеріальний або вірусний чинник. Діагностика синдрому Еді переважно заснована на клінічному зіставленні симптомів захворювання, а також на ретельному й всебічному огляді нейроофтальмолога з обов’язковим проведенням тестування зіничних реакцій за допомогою низьких доз пілокарпіну (характерне звуження зіниці). Незважаючи на позитивний прогноз щодо життя хворого і його працездатності, стан належить до групи складнокурабельних, а лікування зводиться до симптоматичної корекції зору.

Segmental anhidrosis and heat intolerance

A 62 year-old woman with no previous medical history presented to the Dermatology department with sweating disorders for several years. She described segmental hyperhidrosis and hyperemia while running. This excessive sweating occurred in the left hemiface, the left half of the trunk, the left upper limb and the right lower limb (Fig. 1A). This was associated with heat intolerance and previous faintness during sport. She did not describe any chest pain before faintness and the cardiac auscultation was normal. The neurological examination revealed a diffuse areflexia in the absence of any sensory or motor disorders. By illuminating the right eye, we observed a delay in ipsilateral pupillary contraction, whereas we observed an absence of the consensual photomotor reflex of the right eye by illuminating the left eye (Adie's tonic pupil, Fig. 1B and C, and Supplementary file 1). However, she did not complain of reduced visual acuity. Ross syndrome is a rare autonomic disorder caused by a selective degenerative process of the postganglionic cholinergic sudomotor neurons [[1]Sommer C. Lindenlaub T. Zillikens D. Toyka K.V. Naumann M. Selective loss of cholinergic sudomotor fibers causes anhidrosis in Ross syndrome.Ann Neurol. 2002; 52: 247-250Google Scholar]. Ross syndrome is diagnosed by the presence of a triad of symptoms associating segmental anhidrosis (with compensatory hyperhidrosis), Adie's tonic pupil and areflexia [[2]Mishra A.K. Kharkongor M. Kuriakose C.K. George A.A. Peter D. Carey R.A.B. et al.Is ross syndrome an autoimmune entity? A case series of 11 patients.Can J Neurol Sci. 2017; 44: 318-321Google Scholar]. The main complaint of patients is generally the segmental compensatory hyperhidrosis, the anhidrosis in contrast is not even noticed. The two other signs must be specifically examined for to make the diagnosis. The deep tendon hyporeflexia or areflexia affects the four limbs, whereas the tonic pupil is observed on the pathological and anhidrotic side of the face. It has been proposed to treat hyperhidrosis with botulinum toxin [[3]Bergmann I. Dauphin M. Naumann M. Flachenecker P. Müllges W. Koltzenburg M. et al.Selective degeneration of sudomotor fibers in Ross syndrome and successful treatment of compensatory hyperhidrosis with botulinum toxin.Muscle Nerve. 1998; 21: 1790-1793Google Scholar], but this treatment may theoretically increase the heat intolerance and the risk of faintness during sport. Even if the disorder is benign, the objective is to avoid any faintness. Clinicians should advise patients with Ross syndrome to wear light clothing for sports and to avoid excessive heat exposure.

No evidence for a modulating effect of continuous transcutaneous auricular vagus nerve stimulation on markers of noradrenergic activity.

Although transcutaneous auricular vagus nerve stimulation (taVNS) is thought to increase central noradrenergic activity, findings supporting such mechanism are scarce and inconsistent. This study aimed to investigate whether taVNS modulates indirect markers of phasic and tonic noradrenergic activity. Sixty-six healthy participants performed a novelty auditory oddball task twice on separate days: once while receiving taVNS (left cymba concha), once during sham (left earlobe) stimulation. To maximize potential effects, the stimulation was delivered continuously (frequency: 25Hz; width: 250μs) at an intensity individually calibrated to the maximal level below pain threshold. The stimulation was administered 10min before the oddball task and maintained throughout the session. Event-related pupil dilation (ERPD) to target stimuli and pre-stimulus baseline pupil size were assessed during the oddball task as markers of phasic and tonic noradrenergic activity, respectively. Prior to and at the end of stimulation, tonic pupil size at rest, cortisol, and salivary alpha-amylase were assessed as markers of tonic noradrenergic activity. Finally, we explored the effect of taVNS on cardiac vagal activity, respiratory rate, and salivary flow rate. Results showed a greater ERPD to both target and novelty compared to standard stimuli in the oddball task. In contrast to our hypotheses, taVNS did not impact any of the tested markers. Our findings strongly suggest that continuous stimulation of the cymba concha with the tested stimulation parameters is ineffective to increase noradrenergic activity via a vagal pathway.

Adie's Pupil after Chickenpox Infection

A 2-year-old girl with recent chickenpox infection was noted to have a fixed and dilated right pupil. Diluted 0.1% pilocarpine eyedrop test was successful in constructing the dilated right pupil. Cranial nerve examination and computer tomography brain scan were otherwise normal. We report this case as internal ophthalmoplegia, or post-viral Adie's pupil, which appears to be extremely rare.

Pupil size and pupillary light reflex in early infancy: heritability and link to genetic liability to schizophrenia.

Measures based on pupillometry, such as the pupillary light reflex (PLR) and baseline pupil size, reflect physiological responses linked to specific neural circuits that have been implicated as atypical in some psychiatric and neurodevelopmental conditions. We investigated the contribution of genetic and environmental factors to the baseline pupil size and the PLR in 510 infant twins assessed at 5 months of age (281 monozygotic and 229 dizygotic pairs), and its associations with common genetic variants associated with neurodevelopmental (autism spectrum disorder and attention deficit hyperactivity disorder) and mental health (bipolar disorder, major depressive disorder and schizophrenia) conditions using genome-wide polygenic scores (GPSs). Univariate twin modelling showed high heritability at 5 months for both pupil size (h2 = .64) and constriction in response to light (h2 = .62), and bivariate twin modeling indicated substantial independence between the genetic factors influencing each (rG = .38). A statistically significant positive association between infant tonic pupil size and the GPS for schizophrenia was found (β = .15, p = .024), while there was no significant association with the GPS for autism or any other GPSs. This study shows that some pupil measures are highly heritable in early infancy, although substantially independent in their genetic etiologies, and associated with common genetic variants linked to schizophrenia. It illustrates how genetically informed studies of infants may help us understand early physiological responses associated with psychiatric disorders which emerge much later in life.