Palpebral Fissure Response to Phenylephrine Indicates Autonomic Dysfunction in Patients With Type 1 Diabetes and Polyneuropathy

Purpose

The superior and inferior tarsal muscles are sympathetically innervated smooth muscles. Long-term diabetes often leads to microvascular complications, such as, retinopathy and autonomic neuropathy. We hypothesized that diabetes induces (1) sympathetic paresis in the superior and inferior tarsal muscles and that this measure is associated with (2) the severity of diabetic retinopathy, (3) the duration of diabetes, and (4) autonomic function. In addition, association between the severity of retinopathy and autonomic function was investigated.

Methods

Forty-eight participants with long-term type 1 diabetes and confirmed distal symmetrical polyneuropathy were included. Palpebral fissure heights were measured bilaterally in response to topically applied 10% phenylephrine to the right eye. The presence of proliferative diabetic retinopathy (PDR) or nonproliferative diabetic retinopathy and disease duration were denoted. Time and frequency derived heart rate variability parameters obtained from 24-hour continuous electrocardiography were recorded.

Results

The difference in palpebral fissure heights between phenylephrine treated and untreated eyes (∆PFH) was 1.02 mm ± 0.29 (P = 0.001). The ∆PFH was significantly lower in the PDR group (0.41 mm ± 0.43 vs. 1.27 mm ± 1.0), F(1,35) = 5.26, P = 0.011. The ∆PFH was lower with increasing diabetes duration, r(37) = -0.612, P = 0.000. Further, the ∆PFH was lower with diminished autonomic function assessed as total frequency power in electrocardiogram (r = 0.417, P = 0.014), and sympathetic measures of very low (r = 0.437, P = 0.010) and low frequency power (r = 0.384, P = 0.025).

Conclusions

The ∆PFH is a simple ambulatory sympathetic measure, which was associated with the presence of PDR, disease duration, and autonomic function. Consequently, ∆PFH could potentially be an inexpensive and sensitive clinical indicator of autonomic dysfunction.

Liraglutide Treatment Does Not Induce Changes in the Peripapillary Retinal Nerve Fiber Layer Thickness in Patients with Diabetic Retinopathy

Purpose: Liraglutide treatment has shown promising anti-inflammatory and nerve regenerative results in preclinical and clinical trials. We sought to assess if liraglutide treatment would induce nerve regeneration through its anti-inflammatory and neurotrophic mechanisms by increasing peripapillary retinal nerve fiber layer (RNFL) thickness in individuals with long-term type 1 diabetes. Methods: Secondary analyses were performed on a prospective, double-blinded, randomized, placebo-controlled trial on adults with type 1 diabetes, distal symmetric polyneuropathy (DSPN), and confirmed diabetic retinopathy, who were randomized 1:1 to either 26 weeks placebo or liraglutide treatment. The primary endpoint was a change in peripapillary RNFL thickness between treatments, assessed by optical coherence tomography. Results: Thirty-seven participants were included in the secondary analysis. No differences in mean peripapillary RNFL thickness (overall ΔMean RNFL thickness; liraglutide -1 (±8) μm (-1%) vs. placebo -1 (±5) μm (-1%), P = 0.78, n = 37) or any of the quadrants. Peripapillary RNFL thicknesses were shown between treatments in either nonproliferative (ΔMean RNFL thickness; liraglutide -1 (±5) μm (-1%) vs. placebo 0 (±4) μm (0%), P = 0.80, N = 26) or proliferative diabetic retinopathy subgroup (ΔMean RNFL thickness; liraglutide -2 (±14) μm (-3%) vs. placebo -1 (±6) μm (-2%), P = 0.88, N = 11). Conclusions: In this study, 26 weeks of liraglutide treatment did not induce measurable changes in the assessed optic nerve thickness. Thus, this methodology does not support the induction of substantial nerve regeneration in this cohort with established retinopathy and DSPN. The trial was approved by the Danish Health and Medicines Authority. Informed consent was obtained from all participants. TODINELI study: EUDRA CT: 2013-004375-12, Ethics Ref: N-20130077 Clinical trial registration number: clinicaltrials.gov NCT02138045.

Macular oedema and changes in macular thickness in multiple sclerosis patients treated with fingolimod

Macular oedema is a known side effect to fingolimod, but changes in specific areas of the retina are only sparsely described. Our aim was to investigate the prevalence of macular oedema and characterize macular changes after initiation of fingolimod based on routine ophthalmological examinations in all consecutive patients treated at our hospital. We evaluated macular thickness change from baseline to 3-4 months after initiation of treatment. Central retinal thickness, total macular volume, total macular thickness, average thickness and inner-/outer macular thickness were automatically measured using optical coherence tomography (OCT). A total of 190 eyes completed the study, and none of those developed visible macular oedema. All macular areas showed a small, but statistically significant increase in thickness. Total macular volume increased by a mean of 0.05 mm³ (P = <.001). Mean best-corrected visual acuity only changed by .03 (P = .074). We observed a minimal change in macular thickness and no clinically relevant affection on visual acuity after 3-4 months of fingolimod treatment. Thus, our results do not underpin the need for routine screening for macular oedema in asymptomatic MS patients without diabetes or uveitis receiving 0.5 mg fingolimod daily.

Brain spectroscopy reveals that N-acetylaspartate is associated to peripheral sensorimotor neuropathy in type 1 diabetes

AIMS

Emerging evidence shows, that distal symmetric peripheral neuropathy (DSPN) also involves alterations in the central nervous system. Hence, the aims were to investigate brain metabolites in white matter of adults with diabetes and DSPN, and to compare any cerebral disparities with peripheral nerve characteristics.

METHODS

In type 1 diabetes, brain metabolites of 47 adults with confirmed DSPN were compared with 28 matched healthy controls using proton magnetic resonance spectroscopy (H-MRS) in the parietal region including the sensorimotor fiber tracts.

RESULTS

Adults with diabetes had 9.3% lower ratio of N-acetylaspartate/creatine (NAA/cre) in comparison to healthy (p < 0.001). Lower NAA/cre was associated with lower sural (p = 0.01) and tibial (p = 0.04) nerve amplitudes, longer diabetes duration (p = 0.03) and higher age (p = 0.03). In addition, NAA/cre was significantly lower in the subgroup with proliferative retinopathy as compared to the subgroup with non-proliferative retinopathy (p = 0.02).

CONCLUSIONS

The association to peripheral nerve dysfunction, indicates concomitant presence of DSPN and central neuropathies, supporting the increasing recognition of diabetic neuropathy being, at least partly, a disease leading to polyneuropathy. Decreased NAA, is a potential promising biomarker of central neuronal dysfunction or loss, and thus may be useful to measure progression of neuropathy in diabetes or other neurodegenerative diseases.

Cataract surgery education in member countries of the European Board of Ophthalmology

PURPOSE

To address the use of and knowledge about skills assessment and competency-based training in cataract surgery in European Board of Ophthalmology (EBO) member countries.

METHODS

A survey was emailed directly to all directors of the European societies in ophthalmology. The survey included queries about criteria to undergo training in cataract surgery, regulation of education in cataract surgery, and skills assessment and training methods. In addition, all Danish Eye Departments were further asked to what extent they find assessment tools useful, if competency-based training in cataract surgery would be an improvement, and if an assessment tool would be considered for use in future training of cataract surgeons.

RESULTS

Training in cataract surgery in EBO countries is very diverse; although some EBO countries consider it mandatory in residency, most do not. In EBO countries where training is mandatory and regulated by the local health authority, the use of skills assessment tools and competency-based education are more prevalent (e.g., U.K., Ireland, Switzerland, and the Netherlands). In Denmark, training in cataract surgery is not mandatory, and none of the eye departments used assessment scores to evaluate their trainees; 63% did not believe that using assessment tools would improve the outcome of surgical training, and less than one-third would consider frequent use of assessment tools in the future.

CONCLUSION

General unawareness and scepticism toward objective structured assessment of technical skills and a considerable heterogeneity in concept and organization of training in cataract surgery across EBO countries is an issue to address.

[A varix of the vortex vein ampulla is a rare differential diagnosis of malignant melanoma of the choroid]

Melanoma of the choroid is the most frequent primary intra-ocular malignancy whereas a varix of the vortex vein ampulla is a benign, rare and asymptomatic condition requiring no treatment. A varix of the vortex vein ampulla is usually found accidentally and can easily be mistaken for a choroidal melanoma, a naevus or a haemorrhage. We present a case of a varix of the vortex vein ampulla, which can be distinguished from other more serious conditions by using simple clinical methods.

[Photographic screening for diabetic retinopathy in the county of North Jutland. The first fully digitalized telemedicine-screening clinic]

Screening for diabetic retinopathy was introduced in Denmark in 1988. At present, screening is carried out in four of the 14 counties, thus being available to a minority of diabetic subjects. According to the WHO but also the National Board of Health, all diabetic patients should undergo screening for diabetic retinopathy. Not only does screening pay off in terms of preservation of vision, it is also cost-effective, as confirmed in the present study. The first fully digitized clinic for retinopathic screening in diabetic patients was recently introduced in the County of North Jutland. Preliminary results from this clinic indicate that all procedures can be handled in this fully digitized system. We therefore predict that fully digitized clinics for retinopathic screening will be introduced throughout Denmark in the future.

Retinal detachment after cataract extraction in myopic eyes

PURPOSE

To determine the incidence of retinal detachment (RD) after cataract extraction in people 40 years of age or older with axial myopia (i.e., axial length > or = 25.5 mm).

SETTING

Fifteen Danish eye clinics.

METHODS

Two hundred forty-five eyes had cataract extraction performed at 15 eye clinics; 237 eyes had extracapsular cataract extraction (ECCE) and 8 eyes, intracapsular cataract extraction (ICCE). Postoperative data were reported by the practicing ophthalmologists. Mean follow-up was 27 months (range 14 to 32 months).

RESULTS

Five RDs occurred in the 245 eyes (2.0%). Excluding the ICCE cases and the two cases of combined cornea transplantation and ECCE, RD occurred in 4 of the 235 eyes that had ECCE (1.7%). The incidence after ECCE with posterior chamber lens implantation was 1.4%. Complete postoperative status was reported on 158 eyes. Forty-eight eyes (30.4%) had a neodymium:YAG capsulotomy and 3 (6.0%) developed an RD 1, 3.5, and 21 months after the capsulotomy.

CONCLUSION

The RD incidence after ECCE with posterior chamber lens implantation was low but higher than that in unselected populations. The incidence increased after laser capsulotomy.

[Risk of cataract surgery in patients with myopia. A prospective Danish multicenter study with special reference to a complication]

A prospective Danish multicentre study was conducted to evaluate the incidence of retinal detachment after cataract extraction in myopic eyes (axial length, > or = 25.5 mm). Two hundred and forty-seven cataract extractions in myopic eyes were reported during a period of 13 months. Two hundred and forty-one eyes underwent extracapsular and six eyes intracapsular cataract extraction. The mean follow-up time for 158 eyes was seven months (ranging from 1-30 months). In five cases a retinal detachment was observed, one case was probably present preoperatively, this person had undergone intracapsular cataract extraction. The incidence of retinal detachment was thus 1.62-2.02% in the total material and 1.66% in eyes operated with extracapsular cataract extraction.

Some metabolic changes during human corneal organ culture

In order to evaluate the changes in medium composition during closed system corneal organ culture at 30 degrees C, pH, pO2, glucose and lactate was measured 1 to 7, 14 and 28 days after incubation of a total of 49 human corneas. During organ culture pO2 decreased from 17.3 kPa to 8.8 kPa at day 28. The average oxygen consumption was initially 0.16 mumole/h/cm2, but decreased rapidly to an average of 0.04 mumole/h/cm2 during the first weeks of incubation. The glucose concentration fell from 5.1 mM to 0.25 mM after 28 days, and the lactate concentration rose from 2.5 mM to 11 mM. The concentration changes were for both substances highest during the first 14 days of organ culture. The pH fell from 7.36 to 6.64 after 28 days. These findings indicate that the cultured human cornea predominantly metabolizes glucose anaerobically, and that the metabolic activity decreases during incubation. The limiting metabolic factors for prolonging the culture period seem to be development of severe acidosis and glucose depletion in the medium.

Computerised intraocular lens calculation: clinical results and predictability

The predictability of a theoretical, computer-assisted IOL calculation method and of the Sanders-Retzlaff-Kraff (SRK) method was evaluated from pre- and postoperative biometry in 110 cataractous patients subjected to a routine IOL calculation. With the theoretical method and the preoperative data the refraction was on the average 0.72 D (SD 0.78) more myopic than expected, an error which could be corrected for by (1) substituting the assumed postoperative chamber depth by the actual mean value and (2) adding 0.16 mm to the preoperative axial length. With the postoperative data the error was 0.05 D (SD 0.78) (p greater than 0.05). By the SRK method the refraction was 0.15 D (SD 0.71) and 0.37 D (SD 0.69) more hyperopic than expected with the pre- and the postoperative data respectively. These offset errors could be corrected for in either case by adjusting the assumed A constant in the SRK formula. With appropriate empirical corrections for offset errors the theoretical and the SRK method were similar in accuracy, that is, about 82% of the predictions within +/- 1 D, 99% within +/- 2 D, and 100% within +/- 3 D error. The variation in postoperative refraction after computerised IOL calculation was about one-third of the variation previously seen after implantation of standard power IOL.

Double-blind study of naproxen vs placebo in the treatment of acute migraine attacks

Naproxen was compared with placebo in a double-blind, crossover trial in classic and common migraine. The trial was terminated at a fixed date; 37 patients had entered, 5 of whom were excluded. Naproxen was given as 750 mg at the first symptom of the attack, a total of 1250 mg per 24 h was allowed. Patients were followed for six attacks or three months in each phase, whichever came first. The severity of the headache was significantly less with naproxen in the first 2 h of the attack (p = 0.047), whereas there was no difference when the whole attack was considered. Significantly more patients preferred naproxen (p = 0.042). Side effects occurred in five patients, causing withdrawal of one patient while on naproxen.

Amaurosis fugax in a Danish community: a prospective study

A prospective study of amaurosis fugax was carried out in a Danish community (population 481,000); case ascertainment was based on the collaboration of practicing ophthalmologists and general practitioners. Over a 3-year period we registered 131 cases; the annual incidence of "first amaurosis fugax episodes coming to medical attention" was 8.6 and 6.2 per 100,000 population for men and women, respectively. On the basis of a comparison of the age-incidence curves for cerebral and retinal ischemic attacks, the "true" incidence of amaurosis fugax is estimated to be approximately 14/100,000/yr, or 25-30% of the reported incidence of transient ischemic attacks. Clinical and/or radiologic signs of a carotid lesion on the appropriate side were present in 56% of the patients, and an additional 27% had symptoms or signs of other organic cardiovascular disorders. Forty-three (68%) of the 63 patients who underwent arteriography had an atheromatous lesion apparently amenable to carotid endarterectomy. In spite of the case-finding procedures employed in the study, cases of amaurosis fugax suitable for carotid surgery were thus ascertained at a rate of only 3/100,000/yr. This suggests that surgical treatment of patients with retinal ischemic attacks is of minor importance as a preventive measure against stroke in the community.