Pupil abnormalities in selected autonomic neuropathies

Parasympathetic neurons derived from human pluripotent stem cells model human diseases and development

Autonomic parasympathetic neurons (parasymNs) control unconscious body responses, including "rest-and-digest." ParasymN innervation is important for organ development, and parasymN dysfunction is a hallmark of autonomic neuropathy. However, parasymN function and dysfunction in humans are vastly understudied due to the lack of a model system. Human pluripotent stem cell (hPSC)-derived neurons can fill this void as a versatile platform. Here, we developed a differentiation paradigm detailing the derivation of functional human parasymNs from Schwann cell progenitors. We employ these neurons (1) to assess human autonomic nervous system (ANS) development, (2) to model neuropathy in the genetic disorder familial dysautonomia (FD), (3) to show parasymN dysfunction during SARS-CoV-2 infection, (4) to model the autoimmune disease Sjögren's syndrome (SS), and (5) to show that parasymNs innervate white adipocytes (WATs) during development and promote WAT maturation. Our model system could become instrumental for future disease modeling and drug discovery studies, as well as for human developmental studies.

Assessing the Impact of Tropicamide on Anterior Segment Parameters in Diabetic Patients: A Randomized Clinical Trial

INTRODUCTION

Evaluation of anterior segment parameters is crucial in ophthalmic procedures such as intraocular surgeries and contact lens fitting. However, the use of tropicamide in diabetic patients presents challenges due to its potential impact on biometric measurements. This study aims to investigate and compare the effects of 0.5% and 1% tropicamide on anterior segment parameters in diabetic patients.

METHODS

This double-masked randomized clinical trial enrolled 98 patients with diabetes mellitus. Participants were randomly assigned to receive either 0.5% or 1% tropicamide. Anterior segment parameters were measured using Pentacam HR (Oculus Optikgeräte GmbH, Wetzlar, Germany) before and 30 minutes after tropicamide administration. Parameters included anterior chamber depth (ACD), anterior chamber volume (ACV), anterior chamber angle (ACA), keratometry, central corneal thickness (CCT), white-to-white distance (WTW), and pupillary diameter (PD).

RESULTS

Both concentrations of 0.5% and 1% tropicamide induced significant changes in anterior segment parameters. There was a notable increase in PD (2.99 ± 0.62, 3.11 ± 0.55, respectively, both P-values < 0.001), ACD (both 0.10 ± 0.05, both P-values < 0.001), ACV (16.69 ± 9.56, 17.51 ± 9.26, respectively, both P-values < 0.001), and WTW (0.06 ± 0.14, 0.03 ± 0.30, respectively, both P-values < 0.001), along with a decrease in ACA (-3.50 ± 10.65, -3.30 ± 6.87, P-value < 0.001 and P-value=0.001, respectively), and CCT (-6.10 ± 8.06, -6.39 ± 9.97, respectively, both P-values < 0.001) post-dilation. However, no significant changes were observed in keratometry (front Km (-0.03 ± 0.19, -0.04 ± 0.21, respectively), back Km (0.01 ± 0.05, 0.004 ± 0.05, respectively), P-values> 0.05).

CONCLUSION

Both concentrations of tropicamide exhibited comparable effects on anterior segment parameters in diabetic patients. These post-dilation changes should be considered for accurate intraocular lens power calculation and decision-making for cataract, phakic intraocular lens, and refractive surgeries.

Effectiveness of a Standardized Combination of Intracameral Mydriatics and Anaesthetic on Mydriasis during Cataract Surgery with Coexisting Diseases

PURPOSE

To examine the effectiveness of a standardized combination of intracameral mydriatics and anesthetic (SCIMA) on mydriasis in patients with coexisting diseases such as diabetes mellitus (DM) and pseudoexfoliation syndrome (PXF) during phacoemulsification.

METHODS

Patients with cataract were included in the study if they achieved pupil dilation diameter ≥ 6.0 mm after the administration of mydriatic eyedrops (ME) during the first visit (V1). During the second visit (V2), pupil size measurements were obtained for phacoemulsification surgery with SCIMA. Effective mydriasis was defined as a pupil diameter ≥ 6.0 mm just prior to capsulorhexis without the use of additional pupil dilating agents. The measurements after ME administration during V1 and after SCIMA use during V2 were compared.

RESULTS

103 patients (103 eyes) were divided into 3 groups: cataract and DM (n = 35), cataract and PXF (n = 32), and cataract without DM or PXF (n = 36). SCIMA administration allowed the achievement of effective mydriasis (≥6.0 mm) in all groups (n = 103; 100%). Mydriasis was significantly larger (p ≤ 0.001) after ME (7.3 mm) than after SCIMA (6.8 mm) administration.

CONCLUSIONS

Patients with cataract and such comorbidities as DM or PXF are likely to achieve effective pharmacological mydriasis during cataract phacoemulsification after SCIMA application. Mydriasis after ME is slower and larger, while SCIMA is faster.

Norepinephrine transporter defects lead to sympathetic hyperactivity in Familial Dysautonomia models

Familial dysautonomia (FD), a rare neurodevelopmental and neurodegenerative disorder affects the sympathetic and sensory nervous system. Although almost all patients harbor a mutation in ELP1, it remains unresolved exactly how function of sympathetic neurons (symNs) is affected; knowledge critical for understanding debilitating disease hallmarks, including cardiovascular instability or dysautonomic crises, that result from dysregulated sympathetic activity. Here, we employ the human pluripotent stem cell (hPSC) system to understand symN disease mechanisms and test candidate drugs. FD symNs are intrinsically hyperactive in vitro, in cardiomyocyte co-cultures, and in animal models. We report reduced norepinephrine transporter expression, decreased intracellular norepinephrine (NE), decreased NE re-uptake, and excessive extracellular NE in FD symNs. SymN hyperactivity is not a direct ELP1 mutation result, but may connect to NET via RAB proteins. We found that candidate drugs lowered hyperactivity independent of ELP1 modulation. Our findings may have implications for other symN disorders and may allow future drug testing and discovery.

[Paraneoplastic ophthalmopathies]

Ocular paraneoplastic syndromes are rare conditions that can affect any part of the eye at any age. Thus, every ophthalmologist should be familiar with their management, as some of them may reveal severe, life-threatening conditions. These consist overwhelmingly of neuro-ophthalmological manifestations, affecting the optic nerve (paraneoplastic optic neuritis), retina (paraneoplastic retinopathy) or neurological pathways generating eye movements (saccadic intrusion, oculomotor palsy, nystagmus...); occasionally, they involve the anterior segment, orbit or uveal tract. As some of these manifestations appear to be quite common and non-specific, any systemic or especially neurologic comorbidities should increase suspicion. Treatment relies first on oncologic management, and then often more targeted therapy for the associated immune involvement.

Dilute pilocarpine test for diagnosis of Adie's tonic pupil

We have compared the diagnostic ability of different concentrations of 0.125% and 0.0625% dilute pilocarpine for detecting denervation supersensitivity in unilateral Adie's tonic pupil. This retrospective, observational, case-control study involved 117 subjects, consisting of 56 patients with unilateral Adie's tonic pupil and 61 controls with other causes of unilateral dilated pupils. Subjects underwent the dilute pilocarpine test with one of the two concentrations, 0.125% or 0.0625%. Pupillary light reflex was recorded with a dynamic pupillometer at baseline and at 30-40 min after instilling one of the two concentrations of dilute pilocarpine. Diagnostic accuracy of two different concentrations of the dilute pilocarpine test, 0.125% group versus 0.0625% group, were compared by area under the receiver operating characteristic curve (AUC). Diagnostic ability of the dilute pilocarpine test for detecting denervation supersensitivity in unilateral Adie's tonic pupil was significantly better in the 0.0625% group than in the 0.125% group (AUC = 0.954 vs. 0.840, respectively, P = 0.047). In the 0.0625% group, the change in maximal pupil diameter of ≥ 0.5 mm after topical pilocarpine instillation showed 100% sensitivity and 82.8% specificity for detecting Adie's tonic pupil. This study confirmed that pupillary constriction with 0.0625% pilocarpine is better than 0.125% pilocarpine for detecting denervation supersensitivity in Adie's tonic pupil. Digital pupillometry is a reliable method for assessing denervation supersensitivity in Adie's tonic pupil.

Pupillary light reflex as a diagnostic aid from computational viewpoint: A systematic literature review

This work presents a detailed and complete review of publications on pupillary light reflex (PLR) used to aid diagnoses. These are computational techniques used in the evaluation of pupillometry, as well as their application in computer-aided diagnoses (CAD) of pathologies or physiological conditions that can be studied by observing the movements of miosis and mydriasis of the human pupil. A careful survey was carried out of all studies published over the last 10 years which investigated, electronic devices, recording protocols, image treatment, computational algorithms and the pathologies related to PLR. We present the frontier of existing knowledge regarding methods and techniques used in this field of knowledge, which has been expanding due to the possibility of performing diagnoses with high precision, at a low cost and with a non-invasive method.

Anti-Hu Antibody-Associated Adie's Pupil and Paraneoplastic Sensorimotor Polyneuropathy Caused by Primary Mediastinal Small Cell Carcinoma

We report a woman with unilateral Adie's pupil associated with peripheral sensorimotor polyneuropathy, elevated anti-Hu antibody, and primary mediastinal small cell carcinoma (SCC). To our knowledge, this is the first report of Adie's pupil in a patient with mediastinal SCC. Although rare, Adie's pupil and sensorimotor polyneuropathy may be the first manifestation of cancer. Its rapid recognition facilitates an early diagnosis and treatment.

Pupillary autonomic dysfunction in patients with ANCA-associated vasculitis

OBJECTIVE

To assess autonomic function by infrared dynamic pupillometry in patients with ANCA-vasculitis (AAV) in correlation to autonomic symptoms, disease specific clinical parameters and cardiovascular reflex tests.

METHODS

Patients with AAV and healthy controls underwent pupillometry at rest and after sympathetic stimulation (cold pressor test). Three parasympathetic parameters (amplitude, relative amplitude, maximum constriction velocity) and one sympathetic parameter (late dilatation velocity) were assessed. Results were correlated with clinical parameters, symptoms of autonomic dysfunction (COMPASS31 questionnaire), heart rate variability during deep breathing test and blood pressure response to pain.

RESULTS

23 patients and 18 age-matched controls were enrolled. Patients had a smaller amplitude (1.44 vs. 1.70 mm; p = 0.009) and a slower constriction velocity (4.15 vs. 4.71 mm/s; p = 0.028) at baseline and after sympathetic stimulation (1.47 vs. 1.81 mm, p = 0.001; 4.38 vs. 5.19 mm/s, p = 0.006, respectively). Relative amplitude was significantly smaller in patients after sympathetic stimulation (28.6 vs. 32.5%; p = 0.043), but not at baseline. There was no difference in sympathetic pupillary response between the groups. In patients, parasympathetic pupil response was correlated negatively with age and positively with parasympathetic cardiac response. After adjusting for age, no significant correlation was observed with clinical parameters. However, there was a trend towards a negative correlation with disease duration, vasculitis damage index and CRP.

CONCLUSION

Patients with AAV exhibit parasympathetic pupillary autonomic dysfunction. Although correlations were weak and not significant, pupillary autonomic dysfunction is rather linked to chronic damage than to active inflammation or symptoms of autonomic dysfunction.

Phacoemulsification without preoperative mydriasis in patients with age-related cataract associated with type 2 diabetes

Aim

To study the effect of intracameral injection of preservative-free lignocaine to induce pupil dilatation, without using any preoperative dilating eyedrops or intraoperative mydriatics in patients with age-related cataract associated with type 2 diabetes mellitus.

Design

This was a prospective, observational, and interventional case series conducted at a tertiary eyecare center in rural India.

Materials and methods

A total of 32 patients underwent phacoemulsification under topical anesthesia for visually significant cataract. Preoperative pupillary diameter was measured 3 days prior to surgical procedure under mydriatics (tropicamide 0.8%, phenylephrine hydrochloride 5%). Intraoperative pupillary dilatation was achieved by 1% intracameral lignocaine solution alone. Effective phacoemulsification time (EPT), total surgical time, and final pupillary diameter were recorded at the conclusion of surgery.

Results

The average duration of diabetes was 11.2 (range 5–25) years. There was no difference in dilatation by preoperative pupil-dilating drops (5.2±0.5 mm, range 3–8.3 mm) and intracameral 1% lignocaine during the surgical procedure (P=0.63). There was a negative correlation (r=−0.92) between diabetes duration and dilatation of pupils with dilating drops and intracameral lignocaine. The duration of the surgery, EPT, and phacoemulsification chop had statistically insignificant effects on mydriasis, while the grade of the nucleus had a statistically significant effect on mydriasis. Intracameral lignocaine had no significant effect on blood pressure or pulse. There were no surgical complications that could have compromised the visual outcome. None of the patients developed macular edema in a follow-up period of 3 months; 28 patients (87.5%) had best-corrected visual acuity from 20/30 to 20/20.

Conclusion

Intracameral lignocaine 1% provides sufficient mydriasis for the safe phacoemulsification of cataract in patients with type 2 diabetes of variable duration.

Pupillary Light Reflexes are Associated with Autonomic Dysfunction in Bolivian Diabetics But Not Chagas Disease Patients

Autonomic dysfunction is common in Chagas disease and diabetes. Patients with either condition complicated by cardiac autonomic dysfunction face increased mortality, but no clinical predictors of autonomic dysfunction exist. Pupillary light reflexes (PLRs) may identify such patients early, allowing for intensified treatment. To evaluate the significance of PLRs, adults were recruited from the outpatient endocrine, cardiology, and surgical clinics at a Bolivian teaching hospital. After testing for Chagas disease and diabetes, participants completed conventional autonomic testing (CAT) evaluating their cardiovascular responses to Valsalva, deep breathing, and orthostatic changes. PLRs were measured using specially designed goggles, then CAT and PLRs were compared as measures of autonomic dysfunction. This study analyzed 163 adults, including 96 with Chagas disease, 35 patients with diabetes, and 32 controls. PLRs were not significantly different between Chagas disease patients and controls. Patients with diabetes had longer latency to onset of pupil constriction, slower maximum constriction velocities, and smaller orthostatic ratios than nonpatients with diabetes. PLRs correlated poorly with CAT results. A PLR-based clinical risk score demonstrated a 2.27-fold increased likelihood of diabetes complicated by autonomic dysfunction compared with the combination of blood tests, CAT, and PLRs (sensitivity 87.9%, specificity 61.3%). PLRs represent a promising tool for evaluating subclinical neuropathy in patients with diabetes without symptomatic autonomic dysfunction. Pupillometry does not have a role in the evaluation of Chagas disease patients.

Quantitative assessment of the canine pupillary light reflex

PURPOSE

To develop instrumentation and methods for thorough quantitative assessment of the pupillary light reflex (PLR) in dogs under varying stimulus conditions.

METHODS

The PLR was recorded in normal Dachshunds using a custom system allowing full user control over stimulus intensity, color, and duration. Chemical restraint protocols were compared to determine which protocol provided for optimal baseline stability of pupil size and appropriate eye positioning. A series of white light stimuli of increasing intensity was used to elicit pupil constriction. Pupil images were concurrently recorded using continuous infrared illumination and an infrared-sensitive camera. The PLR was also recorded in response to blue and red stimuli.

RESULTS

With injectable chemical restraint alone, spontaneous fluctuations in pupil size occurred independent of light stimulation, and spontaneous eye movements made it difficult to fully visualize the pupil. Combined injectable chemical and inhalation restraint provided a steady baseline pupil size throughout PLR assessment and allowed for stable positioning of the eye using a conjunctival stay suture. Robust PLRs were elicited with all light colors. PLR constriction amplitude increased with increasing flash intensity and ranged from 5% to 70%.

CONCLUSIONS

A recording system and protocol have been developed to reliably quantify the canine PLR. The techniques and instrumentation will be useful for objective quantitative assessment of the PLR in dogs and other species in research applications and may be useful in clinical veterinary ophthalmology and neurology if PLR abnormalities detected with these procedures can be associated with specific diseases.

Pediatric ptosis as a sign of treatable autonomic dysfunction

PURPOSE

To report the ophthalmic findings in young patients with dopamine β-hydroxylase deficiency and to assess them in the context of other reports in an attempt to discern if ophthalmic criteria may assist in early detection of this debilitating, yet treatable, disorder.

DESIGN

Prospective, observational case series.

METHODS

An ophthalmic examination, including measuring intraocular and systemic blood pressures while supine, sitting, and standing, and eyelid function and pupillary function testing, was completed on 3 young patients with recently documented dopamine β-hydroxylase deficiency at a single institution.

RESULTS

Mean arterial blood pressures were 90.1 ± 18.5 mm Hg supine, 79.1 ± 25.7 mm Hg sitting, and 45.8 ± 11.6 mm Hg standing (P = .021). Mean intraocular pressures in these patients were 15.8 ± 1.0 mm Hg supine, 15.0 ± 3.6 mm Hg sitting, and 7.7 ± 2.3 mm Hg standing (P = .03). Mean palpebral fissure, levator function, and margin reflex distance were 8.2 ± 1.0 mm, 16.0 ± 0 mm, and 2.8 ± 0.6 mm, respectively. Measurable miosis was present in only 1 patient, and pupillary supersensitivity to 2.5% phenylephrine was not observed.

CONCLUSIONS

The ophthalmologic findings of the patients in this case series documented mild ptosis and striking orthostatic reductions in intraocular pressure and mean arterial blood pressure, as might be expected with a lack of intrinsic sympathetic function. Orthostatic intraocular pressure and mean arterial blood pressure may be a helpful early screening tool for autonomic dysfunction in children undergoing a ptosis evaluation.

Pupillometry in congenital central hypoventilation syndrome (CCHS): quantitative evidence of autonomic nervous system dysregulation

INTRODUCTION

Congenital central hypoventilation syndrome (CCHS) is characterized by alveolar hypoventilation, autonomic nervous system (ANS) dysregulation (ANSD), and mutations in the paired-like homeobox 2B (PHOX2B) gene. ANSD in CCHS affects multiple systems and includes ophthalmologic abnormalities. We hypothesized that quantitative pupil measures, obtained using pupillometry, would vary between cases with CCHS and controls and within those with CCHS by PHOX2B genotype.

RESULTS

Measures known to be illustrative of sympathetic and parasympathetic response (prestimulus, maximum pupil diameter, percentage of pupil constriction after light stimulus, and average constriction and dilation velocities) were significantly reduced in those with CCHS as compared with controls (all P < 0.05).

DISCUSSION

These reductions are indicative of both sympathetic and parasympathetic deficits in CCHS, which is in keeping with the role of PHOX2B in ANS development. An inverse linear relationship was apparent in pupil diameter and velocity measurements among the cases with CCHS with the most common heterozygous PHOX2B polyalanine expansion repeat mutations, suggesting a graded phenotype/genotype dose response based on polyalanine repeat length. These results confirm our central hypotheses while offering the first objective measures of pupillary dysfunction and ophthalmologic-specific ANSD in CCHS.

METHODS

A total of 316 monocular measurements were taken under dark-adapted conditions with a fixed light stimulus from 22 PHOX2B mutation-confirmed cases with CCHS and 68 healthy controls.

Disorders of pupillary structure and function

Neurologists are frequently consulted because of a pupillary abnormality. An unequal size of the pupils, an unusual shape, white colored pupils, or a poorly reactive pupil are common reasons for referral. A directed history and careful observation of the iris and pupil movements can bear out ocular pathology such as congenital or structural anomalies as the cause of abnormal pupils. Thereafter, it is important to evaluate the neurologic causes of anisocoria and poor pupil function. The first part of this article emphasizes pupillary abnormalities frequently encountered in infants and children and discusses some of the more common acquired iris structural defects. The second part focuses on evaluation of lesions in the neural pathways that result in pupillary dysfunction, with particular attention to those conditions having neurologic, systemic, or visual implications.

Using dynamic pupillometry as a simple screening tool to detect autonomic neuropathy in patients with diabetes: a pilot study

Background

Autonomic neuropathy is a common and serious complication of diabetes. Early detection is essential to enable appropriate interventional therapy and management. Dynamic pupillometry has been proposed as a simpler and more sensitive tool to detect subclinical autonomic dysfunction. The aim of this study was to investigate pupil responsiveness in diabetic subjects with and without cardiovascular autonomic neuropathy (CAN) using dynamic pupillometry in two sets of experiments.

Methods

During the first experiment, one flash was administered and the pupil response was recorded for 3 s. In the second experiment, 25 flashes at 1-s interval were administered and the pupil response was recorded for 30 s. Several time and pupil-iris radius-related parameters were computed from the acquired data. A total of 24 diabetic subjects (16 without and 8 with CAN) and 16 healthy volunteers took part in the study.

Results

Our results show that diabetic subjects with and without CAN have sympathetic and parasympathetic dysfunction, evidenced by diminished amplitude reflexes and significant smaller pupil radius. It suggests that pupillary autonomic dysfunction occurs before a more generalized involvement of the autonomic nervous system, and this could be used to detect early autonomic dysfunction.

Conclusions

Dynamic pupillometry provides a simple, inexpensive, and noninvasive tool to screen high-risk diabetic patients for diabetic autonomic neuropathy.

A pharmacologic pupillary test in the diagnosis of diabetic autonomic neuropathy

Purpose

To screen for diabetic autonomic neuropathy of the pupil using 0.5% apraclonidine and 0.1% pilocarpine and to evaluate the early diagnostic value of this pharmacologic pupillary test by assessing the relationship between pupillary and cardiovascular autonomic neuropathies.

Methods

A total of 22 diabetic patients were recruited. Baseline pupillary diameter (PD) and the difference in PD between the test eye and the control eye before and after instillation of apraclonidine and pilocarpine were measured. All patients also underwent cardiovascular autonomic function (CAF) testing.

Results

Baseline PD in room light correlated with duration of diabetes mellitus (DM, p=0.049) and the presence of DM retinopathy (DMR, p=0.022). Eleven patients (50%) had positive apraclonidine tests, and two patients had positive pilocarpine tests. The patients who had positive pilocarpine tests also had positive apraclonidine tests. Patients who had a positive pupillary test had a significantly higher rate of positive CAF tests (p=0.032).

Conclusions

Pupillary autonomic neuropathy was related to the duration of diabetes and the degree of DMR. There was also a significant correlation between pupillary autonomic neuropathy and cardiovascular autonomic neuropathy (CAN). Also, sympathetic nerve dysfunction occurred prior to parasympathetic dysfunction in this study. A simple pharmacologic pupillary test can help manage complications in diabetic patients because patients with pupillary autonomic dysfunction have an increased risk of CAN.

Pupil abnormalities in 131 cases of genetically defined inherited peripheral neuropathy

AIM

To investigate and correlate the frequency and types of pupil abnormalities that are associated with hereditary peripheral neuropathy in a large cohort of patients prospectively examined.

METHODS

A prospective study between 1998 and 2007. Patients were enrolled and examined after being seen in the neurology clinic. Data were collected on demographics, family and medical history. Patients had eye and pupillography testing carried out as well as being neurologically and genetically investigated.

RESULTS

A consecutive series of 131 cases of inherited peripheral neuropathy were seen and categorized into five groups: familial amyloid polyneuropathy (FAP), Charcot Marie Tooth disease (CMT), hereditary neuropathywith liability to pressure palsies (HNPP), Refsum's disease, and hereditary sensory and autonomic neuropathy. A number of unreported mutations were identified in these patient groups. Pupil abnormalities were common in the Refsum's group, with frequent abnormally small pupils. The inherited neuropathies commonly associated with autonomic abnormalities were frequently found to have developed bilateral Horner's syndrome, which was particularly prevalent in our FAP series. Abnormalities were rare in HNPP and CMT type 1, but CMT type 2 showed frequent and varied pupil defects. The results describe the pupil abnormalities that were frequently associated with the particular group of inherited neuropathy patients, but we could not predict the genetic defect or the neuropathy severity.

CONCLUSIONS

This is the first study of the pupil abnormalities found in the inherited neuropathies and provides an overview of the frequency and type of defects seen in a large number of cases. This series along with the detailed tables will act as an important diagnostic aid in assessing these patients.

An approach to the assessment of diabetic neuropathy based on dynamic pupillometry

Autonomic neuropathy (AN) is a common and serious complication of diabetes. Early detection is essential to enable appropriate interventional therapy. It has long been recognized that subjects with diabetic peripheral neuropathy (DPN) are at much greater risk of developing AN, but there is currently no simple screening tool to assess them. The aim of this study was to investigate pupil responsiveness in diabetic subjects with and without DPN using dynamic pupillometry. During the first test, one flash was administered and the pupil response recorded for 3 seconds. In the second test, twenty-five flashes at one-second intervals were administered and the pupil response recorded for 30 seconds. Several time related parameters were computed from the results. A total of 29 diabetic subjects (17 no DPN, 12 DPN) and 25 healthy volunteers took part in the study. In the first test, pupil-iris ratios in darkness, large deviation and plateau were significantly different between groups. Latency time from flash exposure to the start of constriction was significantly longer in diabetic subjects with DPN compared to healthy volunteers. There was no difference in latency times of largest deviation, plateau or duration of constriction between groups. In the second test, the pupil-iris ratios evaluated in the frame preceding the tenth and the twenty-fifth light flash were significantly greater in healthy volunteers than diabetic subjects with DPN. Latency time from the tenth and twenty-fifth flash exposure to the start of constriction was significantly shorter in healthy volunteers than in diabetic subjects with DPN.

Pupil findings in a consecutive series of 150 patients with generalised autonomic neuropathy

AIM

To detect and characterise the pattern and extent of pupil abnormalities in patients with generalised autonomic failure.

METHODS

A consecutive series of 150 patients referred for investigation of symptomatic generalised autonomic failure underwent pupil investigations. Infra-red video pupillography was used to measure resting pupil diameters in light and dark, the light reflex response, the miosis associated with an accommodative effort, and responses to topical administration of various pharmacological agents. The results were compared with data recorded under identical conditions from a cohort of 315 age-matched and sex-matched healthy controls.

RESULTS

Overall, two thirds of patients had abnormal pupils (66%) with sympathetic deficit occurring twice as often as parasympathetic deficit. However, the prevalence and type of pupil abnormality showed wide variation according to aetiology--for example, almost all patients with amyloidosis had abnormal pupils, two thirds with pure autonomic failure but less than a quarter with multiple system atrophy. In most patients (85%), pupil abnormalities were bilateral and symmetrical, none had a Horner's syndrome in one eye and a tonic pupil in the other. No significant correlation between the type of pupil abnormality and the predominant type of systemic autonomic deficit was seen in most conditions.

CONCLUSIONS

The pupils are often affected in autonomic neuropathy, although this is not always apparent either to the patient or to their doctors. Considerable care is needed not only to detect these abnormalities but also to interpret correctly the results of pupil tests in this group of patients.