Early Hemodynamic Effects of Mydriatic Eye Drops in Preterm Infants

OBJECTIVE

 Mydriatic eye drops used for retinopathy of prematurity (ROP) examination can cause systemic effects, and there are case reports of serious adverse effects in the literature. In this prospective study, we aimed to evaluate the early hemodynamic effects of mydriatic eye drops to understand the possible mechanisms of adverse effects.

STUDY DESIGN

 Between December 2018 and March 2019, preterm babies less than 32 gestational weeks and who underwent ophthalmologic examination in our unit were included. The vital signs (heart rate, respiratory rate, oxygen saturation [SpO2], and blood pressure values), cerebral and mesenteric tissue saturation by near-infrared spectroscopy (NIRS), and left ventricular functions of infants were recorded before and after applying mydriatic eye drops (2.5% phenylephrine and 0.5% tropicamide). The data were compared statistically. Strict adherence to prevent systemic absorption of the eye drops was applied.

RESULTS

 Thirty-two mydriasis procedures were evaluated in 26 patients. The mean gestational age was 28.5 ± 1.7 weeks, and the mean birth weight was 943 ± 233 g. There were no significant differences in terms of vital signs of infants including heart rate, blood pressure, and oxygen saturation [SpO2] levels before and after eye-drop application. In addition, NIRS values showed no significant differences between before and after measurements. No significant differences were detected at echocardiographic evaluation performed before and after mydriatic administration. No adverse reaction was observed in the study population during the study.

CONCLUSION

 This is the first study that evaluated the early hemodynamic effects of mydriatic eye drops used for ROP screening by vital signs, NIRS, and echocardiographic evaluation. Mydriatic eye drops have no significant effect on early hemodynamic parameters including vital signs, NIRS, and echocardiographic findings in preterm infants. We suggest that a cautious approach for avoiding the systemic absorption of these agents may prevent the possible early systemic effects in this high-risk population.

KEY POINTS

· Mydriatic eye drops are commonly used for pupil dilatation before retinopathy of prematurity examination, and there are reports of serious adverse events caused by these drops.. · Due to the adverse events of eye drops, hemodynamic effects of these agents were investigated by clinical findings, near-infrared spectroscopy, and echocardiography.. · No significant early hemodynamic effect was observed so avoiding systemic effects may be prevented with precautions..

Phentolamine Eye Drops Reverse Pharmacologically Induced Mydriasis in a Randomized Phase 2b Trial

SIGNIFICANCE

After a dilated eye examination, many patients experience symptoms of prolonged light sensitivity, blurred vision, and cycloplegia associated with pharmacological mydriasis. Phentolamine mesylate ophthalmic solution (PMOS) may expedite the reversal of mydriasis in patients, potentially facilitating return to functional vision and reducing barriers to obtaining dilated eye examinations.

PURPOSE

The protracted reversal time after pharmacologically induced pupil dilation impairs vision. We tested the hypothesis that PMOS rapidly reduces pupil diameter in this acute indication.

METHODS

In this double-masked placebo-controlled, randomized, two-arm crossover phase 2b trial, we evaluated the effects of one drop of 1% PMOS applied bilaterally in subjects who had their pupils dilated by one of two common mydriatic agents: 2.5% phenylephrine or 1% tropicamide. End points included change in pupil diameter, percent of subjects returning to baseline pupil diameter, and accommodative function at multiple time points.

RESULTS

Thirty-one subjects completed the study (15 dilated with phenylephrine and 16 with tropicamide). Change in pupil diameter from baseline at 2 hours after maximal dilation with 1% PMOS was -1.69 mm and was significantly greater in magnitude compared with placebo for every time point beyond 30 minutes (P < .05). At 2 hours, a greater percentage of study eyes given 1% PMOS returned to baseline pupil diameter compared with placebo (29 vs. 13%, P = .03), which was this also seen at 4 hours (P < .001). More subjects treated with PMOS in the tropicamide subgroup had at least one eye returning to baseline accommodative amplitude at 2 hours (63 vs. 38%, P = .01). There were no severe adverse events, with only mild to moderate conjunctival hyperemia that resolved in most patients by 6 hours.

CONCLUSIONS

Phentolamine mesylate ophthalmic solution at 1% reversed medically induced pupil dilation more rapidly than placebo treatment regardless of which mydriatic was used (adrenergic agonists and cholinergic blockers) with a tolerable safety profile.

Experimental Model of Far Temporal Field Negative Dysphotopsia Generated in Phakic Eyes

Purpose

The axial separation between the iris and the intraocular lens (IOL) in pseudophakic eyes can cause rays originating from the far temporal field to miss the IOL, resulting in negative dysphotopsia (ND). We developed an experimental model to test the hypothesis that obstruction of rays from the far temporal field can generate ND and an accompanying loss of visual sensitivity in the far temporal field.

Methods

The right eyes of 10 phakic subjects were fitted with soft contact lenses containing a 5.50-mm central clear zone and a 12-mm outer diameter opaque annulus. In three of the subjects, eyes were dilated with 1% tropicamide solution, and effective aperture diameters were determined optically (pupil camera) and psychophysically (narrow beam detection). Visual field extent (Goldmann bowl) and temporal and inferotemporal meridian sensitivities (Octopus perimeter) were measured. A wide-angle model was constructed to quantify the impact of the annular opacity on retinal illuminance.

Results

All 10 subjects observed a dark crescent in the far temporal and inferotemporal fields. The opaque annulus reduced effective horizontal pupil diameters from 8 mm to 5.5 mm on-axis and from >2 mm to <1 mm at 90°. Perimetry revealed a 10° reduction in temporal and inferotemporal field extent and increasing loss of sensitivity beyond 70°. The wide-angle model confirmed significant vignetting (>50% beyond 70°), approaching zero retinal illuminance beyond 85°.

Conclusions

Vignetting of rays originating from the far temporal field by axially separated apertures can create symptoms mirroring perceptual reports of negative dysphotopsia in symptomatic pseudophakic patients.

Effect of plum-blossom needling versus tropicamide eye drops on adolescent myopia: protocol for a randomized crossover trial

OBJECTIVE

Myopia is the most common eye problem and affects an estimated 28.3% of the global population. Its incidence is increasing annually. Myopia treatment is limited to correcting visual acuity. Acupuncture is one of the main therapies in traditional Chinese medicine and includes plum-blossom needling, which has been widely used for both the prevention and treatment of adolescent myopia. We hypothesized that plum-blossom needling would be effective in treating myopia compared with a tropicamide eye drops control.

METHODS

This is a crossover randomized controlled trial involving adolescents with myopia. Participants will be randomized 1∶1 to plum-blossom needle or tropicamide eye drops arms. Subjects in each arm will be treated for 20 d, followed by a 1-month washout period and treatment change for another 20 d. The primary outcome is uncorrected distance and cycloplegic refractive errors. The secondary outcomes comprise corneal curvature, lens thickness, axial length, ciliary body thickness, accommodation amplitude, the NRA/PRA (negative/positive relative accommodation), flexible adjustment, and near point of convergence. The outcome measures will be assessed at baseline, after the first treatment course (the first month), at the end of the washout period (the second month), after the second treatment course (the third month), and at follow-up (the sixth month).

DISCUSSION

The results of the trial will help to provide evidence for the efficacy of plum-blossom needling for myopia in China.

Factors Affecting Pupil Reactivity After Cycloplegia in Asian Children

PURPOSE

The aim of this study was to evaluate the factors affecting cycloplegia, as determined by pupil reactivity, in Asian children.

DESIGN

Prospective observational study.

METHODS

Two-hundred sixty-eight children, aged 2 to 12 years, requiring cycloplegic refraction, were recruited. Nurses instilled 2 to 3 cycles of eye drops consisting of cyclopentolate 1%, tropicamide 0.5%, and phenylephrine 2.5%, and recorded the child's level of cooperation. Optometrists recorded pupil reactivity after the last cycle. Multivariate analysis determined factors affecting pupil reactivity including age, sex, race, number of eye drop cycles, pupil sizes before and after cycloplegia, and child's cooperation during eye drops instillation.

RESULTS

The pupils in 36 children (13.4%) were found to be still reactive. On univariate analysis, children with reactive pupils also had smaller pupils after cycloplegia (6.27 ± 1.16 mm vs 7.42 ± 0.81 mm, P < 0.001). On multiple logistic regression analysis, for every 1-mm increase in the pupil size after cycloplegic eye drop administration, the odds of having reactive pupils decreases by 65% (odds ratio = 0.35, 95% confidence interval 0.25-0.51, P ≤ 0.001). Those who were uncooperative during administration of eye drops were 3.13 times more likely to have reactive pupils (95% confidence interval 1.21-8.13, P = 0.019), whereas age (P = 0.904), sex (P = 0.355), the number of cycles of eye drops (P = 0.462), and other psychological factors were not relevant in affecting pupil reactivity.

CONCLUSIONS

Pupil reactivity, which was used as a measure of cycloplegia, was more likely to be affected by children's level of cooperation during instillation of eye drops, rather than age and sex. Two cycles of eye drops were as effective as 3 cycles in producing cycloplegia.

Effects and Side Effects of Mydriatic Eyedrops in Neonates

The pupils of neonates and premature infants often need to be dilated for retinal examination. The drops used for this purpose have some known side effects. This study investigated the effects and side effects of these drops. In this prospective randomized study, 80 healthy neonates were randomly assigned to eight groups. In Group A 1% cyclopentolate was used; in Group B 1% tropicamide; in Group C 2.5% phenylephrine; in Group D 1% cyclopentolate and 1% tropicamide; in Group E 2.5% phenylephrine and 1% tropicamide; in Group F 0.5% cyclopentolate, 0.5% tropicamide and 2.5% phenylephrine; in Group G 1% cyclopentolate and 2.5% phenylephrine and in Group H 0.9% NaCl. Heart rate, systolic and diastolic blood pressures were recorded before, and 5, 10, 15, 30, 45, 60 minutes after instillation of the drops. Pupillary size was measured at baseline, 30 and 60 minutes. To stimulate the conditions of indirect ophthalmoscopic examination, the pupil sizes were measured under the intense beam of a halogen light. The results were analyzed statistically. Maximum side effects were seen in group C; the safest was group B and maximum mydriasis was achieved in group F.

Inhibition of basal and amphetamine-stimulated extracellular signal-regulated kinase (ERK) phosphorylation in the rat forebrain by muscarinic acetylcholine M4 receptors

The mitogen-activated protein kinase (MAPK), especially its extracellular signal-regulated kinase (ERK) subfamily, is a group of kinases enriched in the mammalian brain. While ERK is central to cell signaling and neural activities, the regulation of ERK by transmitters is poorly understood. In this study, the role of acetylcholine in the regulation of ERK was investigated in adult rat striatum in vivo. We focused on muscarinic M1 and M4 receptors, two principal muscarinic acetylcholine (mACh) receptor subtypes in the striatum. A systemic injection of the M1-preferring antagonist telenzepine did not alter ERK phosphorylation in the two subdivisions of the striatum, the caudate putamen and nucleus accumbens. Similarly, telenzepine did not affect ERK phosphorylation in the medial prefrontal cortex (mPFC), hippocampus, and cerebellum. Moreover, telenzepine had no effect on the ERK phosphorylation induced by dopamine stimulation with the psychostimulant amphetamine. In contrast to telenzepine, the M4-preferring antagonist tropicamide consistently increased ERK phosphorylation in the striatum and mPFC. This increase was rapid and transient. Tropicamide and amphetamine when coadministered at subthreshold doses induced a significant increase in ERK phosphorylation. These results demonstrate that mACh receptors exert a subtype-specific modulation of ERK in striatal and mPFC neurons. While the M1 receptor antagonist has no effect on ERK phosphorylation, M4 receptors inhibit constitutive and dopamine-stimulated ERK phosphorylation in these dopamine-innervated brain regions.

Anterior Movement of the Crystalline Lens in the Process of Accommodation in Children

Purpose

To investigate changes of crystalline lens position during accommodation in children with emmetropia, myopia, and hyperopia.

Methods

A total of 188 children (372 eyes) from 4 to 19 years old (mean age 11.3±4.43) with cycloplegic refractive error within a range +9.00 D to −9.00 D were enrolled. After a general ophthalmic examination, ultrasound biometry was performed, with the eye at a maximal accommodative effort. Cycloplegia was induced by triple installation of 1% tropicamide drops and 30 minutes later the biometric examination was repeated.

Results

In emmetropic eyes in the process of accommodation, the anterior pole of the crystalline lens moved forward by 0.144±0.14 mm (p ≤ 0.001); the position of the posterior pole did not change. In myopic eyes, the anterior pole moved forward by 0.071±0.13 mm (p≤0.001) and the posterior pole moved backward by 0.039±0.10 mm (p=0.003). In hyperopic eyes, the whole lens translocated anteriorly: anterior pole moved forward by 0.242±0.16 mm (p≤ 0.001) and posterior pole moved forward by 0.036±0.09 mm (p≤0.001). Differences among emmetropia, myopia, and hyperopia were statistically significant. Forward movement of the posterior pole correlated with a low axial length of the eye, and also with plus refractive error and with a smaller accommodative increase of lens thickness.

Conclusions

In children, accommodative changes of the crystalline lens position depend on refractive status.

Onset and duration of cycloplegic action of 1% cyclopentolate - 1% tropicamide combination

PURPOSE

To study the time course (onset, time and duration of maximal cycloplegia, and the full duration) of cycloplegic action of 1% Cyclopentolate - 1% Tropicamide.

METHODS

Seventy-seven students, aged 15-24 years were purposively sampled from the University of Cape Coast and Cape Coast Technical Institute. Subjective near addition (ADD) determination and pupil diameter measurement before and after a drop of the test agent (1% Cyclopentolate - 1% Tropicamide combination in the right eye) and the control (1% Cyclopentolate in the left eye) were performed. Measurements of subjective near ADD and pupil diameter were made after the initial reading at 5 minutes interval for the first hour and every 30 minutes for the next 7 hours for each participant. Time of onset, time of peak cycloplegia, duration of peak cycloplegia and duration of total cycloplegic effect was indirectly determined.

RESULTS

1% Cyclopentolate - 1% Tropicamide combination had rapid onset of cycloplegia (5-10 minutes), shorter time of maximal cycloplegia (55 versus 90 minutes), and recovery (7 versus ≥ 8hours) in the majority (79.2%) of subjects.

CONCLUSION

Cyclopentolate -Tropicamide combination was comparable to Cyclopentolate in depth of cycloplegia produced, and clinically superior to 1% Cyclopentolate in rapidity of cycloplegic onset, time of maximal cycloplegia and recovery from cycloplegia.

Ocular tolerance in rabbits after intracameral administration of a fixed combination of tropicamide, phenylephrine, and lidocaine with and without rinsing

PURPOSE

To evaluate the safety and tolerability of a single intracameral administration of a combined mydriatic (tropicamide and phenylephrine) and anesthetic (lidocaine) formulation (Mydrane) with or without rinsing.

SETTING

Iris Pharma, La Gaude, France.

DESIGN

Experimental study.

METHODS

Sixty pigmented rabbits received 100 μL or 200 μL of the combination product or a placebo (sodium chloride 0.9%) by intracameral injection. For the combination product, separate groups were included with and without rinsing after administration. From day 1 day to day 7, assessments included general clinical and ocular observations, pupil diameter measurements, corneal assessments, confocal microscopy, and electroretinography (ERG). Necropsy examinations were performed at study completion at day 8.

RESULTS

Rapid mydriasis, stable 24 minutes after injection and returning to baseline levels by day 1, was induced in all groups that received the combination mydriatic and anesthetic drug. Rinsing had no effect. The combination product induced no adverse effects on the anterior or posterior segment of the eye (ie, no increased corneal thickness and endothelial cell loss, no abnormalities in ERG). Slitlamp examination showed slightly increased anterior chamber inflammation with rinsing in both the study group and placebo group. This observation was not confirmed by aqueous flare examination. No toxic effects of the products were found on histological evaluation.

CONCLUSION

The combination mydriatic and anesthetic drug administered to pigmented rabbits as a single intracameral injection at volumes of 100 μL and 200 μL was well tolerated with no ocular adverse effects and no effect on the corneal endothelium.

Efficacy of an eye drop mixture for pupillary dilatation: A randomized comparative study

PURPOSE

Pupillary dilatation with three types of eye drops is used regularly in the clinic; however, a mixture of these drops in a single bottle may be more beneficial in reducing workloads and resources. This study compared the efficacy in pupillary dilatation between two protocols of dilating drop instillation.

METHODS

This prospective, randomized, comparative study included 30 eligible Thai patients. The patients randomly received preoperative pupillary dilatations by either the conventional protocol (1% tropicamide (T), 10% phenylephrine (P) and 0.1% diclofenac (D) in three separate bottles) or the fixed combination (TPD) protocol which had the three types of eye drops mixed in a single bottle in a ratio of 4:3:3. The chi-square test and independent t-test were used to analyze the data.

RESULTS

The conventional protocol group and TPD protocol group each had 15 patients. Sixty minutes after the initial instillation, all patients in the TPD protocol and 13 patients (86.7%) in conventional protocol achieved at least 6mm in the shortest diameter. The mydriatic rate between protocols showed no difference. In patients who received the TPD protocol, the systemic effects on the mean arterial blood pressure and pulse rate decreased over time.

CONCLUSION

The mixture of tropicamide, phenylephrine and diclofenac had a comparable efficacy for a pupillary dilatation to the conventional dilating drops in separate bottles. The systemic complications on blood pressure and arterial pulse of the TPD mixture were less than the conventional protocol.

TRIAL REGISTRATION

TCTR20130325001.

Time-Course of Changes in Choroidal Thickness after Complete Mydriasis Induced by Compound Tropicamide in Children

PURPOSE

The aim of this study was to investigate the time-course of changes in choroidal thickness (ChT) following complete mydriasis induced by compound tropicamide.

METHODS

ChT was measured by OCT with the enhanced-depth imaging technique (Spectralis HRA+OCT, Heidelberg Engineering, Germany) at nine locations of the fundus: subfoveal ChT (SFChT) and ChT at 1 mm and 3 mm from the fovea in four quadrants. Mydriasis was induced with compound tropicamide (0.5% tropicamide plus 0.5% phenylephrine hydrochloride, three doses at 5-minute intervals). Measurements were conducted prior to the instillation and at 0, 30, and 60 min following complete mydriasis. Results at different time-points were compared using repeated-measures ANOVA to investigate the time-course of the changes.

RESULTS

Thirty-nine subjects (mean age 11.9±2 years; 16 males and 23 females) were enrolled in the study. Compound tropicamide resulted in a statistically significant decrease in SFChT at 0, 30, and 60 min after complete mydriasis, as compared to baseline (-5±4 μm, -12±4 μm, and -13±4 μm, respectively; all P<0.0001). No significant changes were detected in the parafoveal choroid except at 1 mm temporal (T1mm) and nasal (N1mm) to the fovea at 30 and 60 min (T1mm: -6±4 μm and -7±5 μm at 30 and 60 min; N1mm: -6±4 μm and -7±5 μm at 30 and 60 min, respectively; all P<0.0001). Repeated-measures ANOVA showed a significant interaction between the time after complete mydriasis and the effect of the mydriasis agent.

CONCLUSIONS

Complete mydriasis induced by compound tropicamide led to choroidal thinning, and the magnitude varied over time.

The effect of topical anti-muscarinic agents on subfoveal choroidal thickness in healthy adults

PurposeTo investigate the effects of tropicamide and cyclopentolate, which are two anti-muscarinic agents commonly used in the ophthalmologic practice, on subfoveal choroidal choroidal thickness (ChT) in healthy adults.MethodsA total of 74 healthy adult subjects were enrolled in the study. Subjects were randomly divided into two groups: (1) cyclopentolate group (n=37) in which the right eye (study eye) of each subject received topical cyclopentolate 1%, and the fellow eye (control eye) received artificial tears and (2) tropicamide group (n=37) in which the right eye (study eye) of each subject received topical tropicamide 1% and the fellow eye (control eye) received artificial tears. Each topical medication was applied three times with 10-min intervals. ChT measurements were performed at baseline and 40 min after the last drops of the topical medications by enhanced depth imaging (EDI) optical coherence tomography (OCT).ResultsIn the cyclopentolate group, subfoveal ChT significantly increased in the study eyes (P=0.013), whereas it did not significantly change in the control eyes (P=0.417). On the other hand, in the tropicamide group, no significant subfoveal ChT changes were observed in either the study eyes (P=0.715) or the control eyes (P=0.344).ConclusionsThe current study demonstrated that cyclopentolate caused significant choroidal thickening, whereas tropicamide had no significant effect on ChT in healthy adults. As a result, mydriasis by cyclopentolate may complicate ChT measurements by EDI OCT. Use of tropicamide may provide more reliable results for evaluation of ChT in ocular pathologies.

Adverse reactions following routine anticholinergic eye drops in a paediatric population: an observational cohort study

OBJECTIVES

To investigate the presence, nature and relationship to age, sex, ethnicity and body mass index (BMI) of adverse reactions following routine cycloplegic eye drops in children.

DESIGN

Prospective observational cohort study.

SETTING

Ophthalmology outpatient clinic Dutch metropolitan hospital; February, March and April 2009.

PARTICIPANTS

Children aged 3-14-year-old children receiving two drops of cyclopentolate 1% (C+C) or one drop of cyclopentolate 1% and one drop of tropicamide 1% (C+T). Patients were categorised by age (3-6, 7-10 and 11-14 years), sex, ethnicity and body mass index (BMI) (low, normal or high).

OUTCOME MEASURES

Rate and nature of adverse reactions reported at 45 min following treatment. Crude and adjusted ORs for reporting an adverse reaction using stepwise regression analysis with BMI, age, ethnicity and sex.

RESULTS

912 of 915 eligible patients participated (99.7%). Adverse reactions were reported for C+C in 10.3% and in C+T in 4.8% (42/408 and 24/504, p=0.002), respectively. Central effects were present in 95% in C+C and in 92% in C+T. Compared to C+T, an increased risk was present in C+C (crude OR 2.3 (1.4 to 3.9), p=0.002). Forward adjustment showed BMI to be an influencing factor in treatment (OR 3.1 (1.7 to 5.6), p<0.001). In a multivariate model, a dose of cyclopentolate remained associated with adverse reactions. Analysis per BMI and regime and age category and regime, indicated associations with low BMI (OR C+C 21.4 (6.7 to 67.96), p<0.001, respectively, C+T 5.2 (2.1 to 12.8), p<0.001) and young age (OR C+C 8.1 (2.7 to 24.8), p<0.001).

CONCLUSIONS

Adverse reactions were common and almost exclusively involved the central nervous system. Both presence and severity were associated with repeated instillation of cyclopentolate 1%, low BMI and young age. In specific paediatric populations, a single dose of cyclopentolate must be considered. Vital function monitoring facilities are advisable. Adjustment of guidelines is recommended.

Comparison of the mydriatic effects of mydrin-P and compound tropicamide in the screening of retinopathy of prematurity

PURPOSE

To observe and compare the effects of pupil dilation between Mydrin-P and compound tropicamide in the screening of retinopathy of prematurity.

METHODS

The right eyes of premature infants received My- drin-P eye drops as the treatment group, whereas the left eyes were administered with compound tropicamide as the control group. The eye drops were delivered every 5 min for three times. The pupil size was observed and recorded at 10, 15, and 20 min after administering mydriasis.

RESULTS

The mean pupil diameter did not significantly differ between the treatment and control groups at 10 (6.24 ± 0.72 mm vs. 6.24 ± 0.68 mm, t = 0.00, P = 1.00), 15 (6.83 ± 0.55 mm vs. 6.78 ± 0.54 mm, t = 1.75, P = 0.083) or 20 min (7.22 ± 0.40 mm vs. 7.15 ± 0.50 mm, t = 1.62, P = 0.109), respectively. How- ever, the mean pupil size at any two time points significantly differed in both groups (all P < 0.001).

CONCLUSION

Both Mydrin-P and compound tropicamide exert similar clinical efficacy in the screening of retinopathy of pre- maturity. The most appropriate time for screening was at 20 min after mydriasis.

Pupil dilation with intra-cameral lidocaine versus topical midriatics during phacoemulsification

PURPOSE

To evaluate pupil dilation with intra-cameral injection of preservative-free lidocaine 1% (ICL) versus topical eye midriatics during phacoemulsification.

METHODS

This case-control study included 40 patients with similar bilateral senile cataract scheduled for phacoemulsification and intraocular lens (IOL) implantation. patient's first eye received topical midriatic eye drops as control group and next eye operated by intra cameral preservative free lidocaine 1% without any preoperative or intraoperative midriatics. We did not add epinephrine to the irrigating solution in either group. The first eyes received 3 drops of cyclopentolate 1% and tropicamide 1% each 5 minutes, with first dose 60 minutes before surgery. The horizontal pupil diameter was measured before and after pupil dilation using the same caliper with operation microscope total surgical time was recorded in both groups.

RESULTS

Patients included 20 male and 20 female with mean age of 72 and 70.9 years old .4 patients were diabetic and 11 cases had pseudo-exfoliation. Pupil diameter increased in both case and control groups significantly (P value<0.0) but the difference between mean increase in pupil size wasn't significantly different. Mean increase in pupil size was significantly greater in patients without pseudo-exfoliation (4.10 mm vs 3.85 mm, independent t test, P<0.05). There was no significant difference between diabetic and non- diabetic patients regarding of pre- and post-injection diameter of the pupil.

CONCLUSION

Intra-cameral preservative-free lidocaine 1% supply adequate midriasis during cataract surgery by itself.

The effect of 0.5% tropicamide/0.5% phenylephrine mixed eye drop in Chinese adults with myopia and its inter-eye difference in refractive outcomes

OBJECTIVE

To evaluate the effect of 0.5% tropicamide/0.5% phenylephrine mixed eye drop and make the inter-eye comparison of refractive outcomes in Chinese adults with myopia.

METHODS

Refractive measurements were performed without cycloplegia and repeated 30 minutes later with 0.5% tropicamide/0.5% phenylephrine mixed eye drop (Mydrin-P*) on 341 myopic adults. Vector analysis was used to analyze the data. Changes of spherical equivalent (M) and astigmatism for both J0 and J45 components between these two refractions were calculated as Error_M, Error_J0 and Error_J45. Inter-eye correlations were studied. The inter-eye difference after cycloplegics were described as Diff M, Diff J0 and Diff J45. The effect of anisometropia, age and the higher order aberrations (HOAs) on inter-eye differences toward the cycloplegic agent were analyzed.

RESULTS

Difference was found only for the Error_J45 component between the two eyes (p=0.0040). Pearson correlation coefficients between the two eyes for Error_M, Error_J0, and Error_J45 were 0.3140 (p<0.0001), 0.1464 (p=0.0068), and 0.0099 (p=0.8558), respectively. The inter-eye differences (Diff) in response to cycloplegic agent increased with the amount of anisometropia. The oldest group had the highest Diff M values. However, HOAs were found not to be related to the inter-eye differences.

CONCLUSIONS

Accommodation was still relaxed by tropicamide/phenylephrine eye drops in myopic adults. The changes of refraction due to cycloplegia were not well correlated between the two eyes in myopic patients. Anisometropia and ocular dominance might be an important factor for the inter-eye difference.

Phenylephrine 5% added to tropicamide 0.5% eye drops does not influence retinal oxygen saturation values or retinal vessel diameter in glaucoma patients

PURPOSE

To test whether adding topical phenylephrine 5% to tropicamide 0.5% eye drops in the protocol for pupil dilation affects the retinal vessel oximeter measurements in patients with glaucoma. To test whether phenylephrine 5% has an influence as a vasoconstrictor on the retinal vessel width and can improve the proportion of high-quality retinal images in patients with glaucoma.

METHODS

Retinal images of 66 patients with chronic open-angle glaucoma were obtained before and after the administration of phenylephrine 5% eye drops to patients already dilated with tropicamide 0.5% with the Oxymap Retinal Oximeter (Oxymap ehf, Reykjavik, Iceland). Specialized software, Oxymap Analyzer, analysed the images and measured the oxygen saturation and vessel diameter. Oxygen saturation was measured in first- and second-degree vessels. A Mann-Whitney U-test was used to compare both groups. Quality of the images was assessed, and a Fisher's exact test was used to compare the proportion of high- and poor-quality images.

RESULTS

There was no significant difference in arterial and venous oxygen saturation in patients with glaucoma whether dilated by tropicamide alone or a combination of tropicamide and phenylephrine (97 ± 6% versus 96 ± 5%, p = 0.88 for arterial saturation and 66 ± 6% versus 67 ± 6%, p = 0.78 for venous saturation, n = 27). There was no significant difference in vessel diameter between both conditions for the different vessels (p = 0.61 for arterial saturation and p = 0.51 for venous saturation, n = 27). The proportion of high-quality images was significantly higher after the combination regimen compared with tropicamide only (p = 0.0001).

CONCLUSION

The addition of topical phenylephrine 5% after tropicamide 0.5% improved the proportion of high-quality retinal oximetry images without influencing the retinal oxygen saturation values or the retinal vessel diameter in patients with glaucoma.

Does pupil dilation influence subfoveal choroidal laser Doppler flowmetry?

PURPOSE

The aim of this study was to assess (i) whether pupil dilation with tropicamide influences subfoveal choroidal blood flow, as assessed by continuous laser Doppler flowmetry (LDF) and (ii) if this is the case, whether the effect is due to a haemodynamic response of the drug-induced dilation.

METHODS

Following the instillation of one drop of 1% tropicamide in one eye of 18 healthy, nonsmoking volunteers (age 20-25 years), the subfoveal choroidal LDF parameters (Vel, Vol and ChBF) were recorded during 30 min, at 3-min intervals under two paradigms: through an artificial pupil (4 mm diameter) placed in front of the cornea (P1) and without this artificial pupil (P2).

RESULTS

Tropicamide increased the pupil diameter from 3.3 ± 0.4 mm (mean ± SD) to 8.3 ± .4 mm. Full dilation was reached at ~24 min. During this period of time, linear regression analysis demonstrated that none of the LDF parameters varied significantly (p > 0.05), either under P1 or P2. Based on a group of 12 subjects, the smallest (%) change in the mean value of ChBF (ChBFm ) that would be detectable (sensitivity of the method, S) was found to be 2% for P1 and 6% for P2. The average coefficient of variation of ChBFm based on eight measurements during dilation was greater for P2 than for P1 by a factor of approximately 2.

CONCLUSION

Tropicamide had no significant influence on the subfoveal choroidal LDF parameters measured by continuous LDF during pupil dilation. Furthermore, pupil dilation did not affect ChBFm by more than the calculated minimum percentage change of 6% detectable with our method.

Accomodative tone in children under general anesthesia

PURPOSE

To determine the effect of general anesthesia on the accommodative tone in children.

DESIGN

Cohort study in an academic practice.

METHODS

In children under 12 years of age who were undergoing general anesthesia, cycloplegic refraction was measured using streak retinoscopy during an office visit. Within 6 months, streak retinoscopy without cycloplegia was performed under general anesthesia. The main outcome measure was the difference between retinoscopy under anesthesia and cycloplegic retinoscopy in children.

RESULTS

In 41 children with an average age of 3.7 years (range, 0.8 to 11 years) retinoscopy under anesthesia yielded significantly more myopic measurements than cycloplegic retinoscopy for the sphere and spherical equivalent (P < 0.0001 for both) but was in good agreement with cycloplegic retinoscopy for cylinder power and axis. The average difference between retinoscopy under anesthesia and cycloplegic retinoscopy was -0.98 diopters (D) (95% limit of agreement, -3.08 D to +1.10 D) for the sphere, 0.08 D (95% limit of agreement, -0.67 D to +0.82 D) for the cylinder, and -0.94 D (95% limit of agreement, -3.01 D to +1.13 D) for the spherical equivalent. Retinoscopy under anesthesia was within 1 D of cycloplegic retinoscopy in 25 subjects (61%) for the sphere, in all subjects for the cylinder, and in 28 subjects (68.3%) for the spherical equivalent.

CONCLUSIONS

Although general anesthesia reduced the accommodative tone in most children, it was still significant in some as compared to the tone found in cycloplegic retinoscopy. If an accurate measurement is essential, cycloplegia is recommended when measuring refraction in children under general anesthesia.

Comparison of the effectiveness of mydriasis by two instillation methods of combined 0.75% tropicamide and 2.5% phenylephrine eye drop in preterm infants

OBJECTIVE

To compare the effectiveness and safety of two instillation methods of combined 0.75% tropicamide and 2.5% phenylephrine at 0, 5 minutes (min) with the same combined regimen at 0,30 minutes in preterm infants.

MATERIAL AND METHOD

A prospective, cross-over, randomized controlled trial was performed to compare 0, 5-min instillation (Method A) of combined 0.75% tropicamide and 2.5% phenylephrine with 0, 30-min instillation (Method B) of the same regimen. Forty-two preterm infants scheduled for screening retinopathy of prematurity (ROP) were randomly assigned to two groups. Group 1 was defined as preterms applied by Method A at first examination then by Method B 1-4 weeks apart whereas vice versa in Group 2. Pupil size, heart rate (HR), systolic and diastolic blood pressure (SBP, DBP) were recorded before and after eye-drop instillation.

RESULTS

Mean time to 7-mm pupil size was no statistically significant difference between the two methods (Method A 46.47 min, Method B 46.58 min; p = 0.894). Method B has mean longer time to maintain 7-mm pupil size than Method A (Method A 67.67 min, Method B 75.33 min); but not statistically significant different (p = 0.323). HR, SBP and DBP were not significant change between the two methods.

CONCLUSION

Both instillation methods produced consistently sufficient mydriasis and safety for evaluation peripheral fundus. Method B has slight longer mydriatic effect than Method A; thus giving more time to evaluate infant's eye for ophthalmologists.

Delayed intraocular pressure elevation after pupillary dilation in exfoliation syndrome

PURPOSE

To determine the effect of pupillary dilation on intraocular pressure (IOP) in normotensive patients with exfoliation syndrome (XFS).

METHODS

Patients with XFS were enrolled in this prospective trial. All eyes were untreated, had no previous laser or operative surgery and were normotensive with full visual fields and open angles. IOP was measured before dilation and hourly for four consecutive hours after dilation with tropicamide 1% and phenylephrine 2.5% eyedrops.

RESULTS

Twenty-five eyes of 19 White patients (nine male, 10 female) with XFS were enrolled. Twelve eyes (48%) had a rise in IOP of ≥ 4 mmHg above the pre-dilation baseline IOP and four (16%) had a rise of ≥ 9 mmHg (9-28 mmHg). Post-dilation gonioscopy confirmed the presence of an open anterior chamber angle in all eyes. The maximum IOP was reached 3 hr post-dilation in three eyes and after 2 hr in the remaining eyes. The four eyes with marked IOP rise exhibited an elevation of between 1 and 7 mmHg at 1 hr. Extensive pigment release was noticed in all eyes that had a rise in IOP.

CONCLUSION

Patients with XFS are at risk of developing delayed post-dilation IOP rises. Awareness of this phenomenon is particularly important in patients with advanced cupping and/or severe visual field loss who may not be able to tolerate a marked elevation of IOP. An early, mild rise in IOP at 1 hr may serve as a warning sign for a more severe, delayed response. Eyes with XFS should be monitored carefully after dilation, especially those with marked pigment release.

Visual recovery using small dilating eye drops

It is well established that reduced size dilating eye drops of 1% tropicamide and 10% phenylephrine (micro drops) are effective for clinical purposes. Excellent pupil dilatation (mydriasis) is achieved and pupil constriction does not occur in response to light. In this study, the effect of micro drops of 1% tropicamide on distance and near visual recovery was compared with standard drops in a group of 20 healthy volunteers. For each person studied, one eye was selected at random to be tested first with the standard drop size, and then after a minimum of one week, the same eye was again tested using a drop of the same drug one fifth standard size. An iris photograph, Snellen visual acuity at 6 m, and reading visual acuity was obtained for each test procedure: before drop instillation and at 30 min, 1, 2 and 4 h after drug instillation. Use of the micro drops caused a small but statistically significant improvement in the rate of recovery of distance and near visual acuity. These findings, allied to the known beneficial effects of reduced systemic absorption using micro drops, lend further weight to the argument that mydriasis may be achieved more safely, with fewer side effects, and with earlier return of normal vision when reduced size drops are used. It is hoped that practical micro drop dispensers will be developed.

Post-Cycloplegia Myopic Shift in an Older Population

PURPOSE

To demonstrate that use of a mydriatic agent remains a significant confounder in autorefraction of the presbyopic population.

METHODS

The pre- and post-cycloplegic autorefraction results of 37 subjects over 50 years of age were measured using a Humphrey-598 autorefractor. The results of both eyes were included in a multivariate regression analysis.

RESULTS

The average age of the patient sample was 63.4 years. The mean spherical equivalent (SEQ) shifts for the hyperopic, myopic, pseudophakic, and emmetropic eyes were -0.53 D (95% CI -0.77 D to -0.39 D; p < 0.001), -0.38 D (95%CI -0.81 D to +0.04 D; p = 0.077), -0.49 D (95% CI -0.78 D to -0.20 D; p = 0.001), and -0.35 D (95% CI -0.59 D to -0.11 D; p = 0.004), respectively.

CONCLUSION

Cyclopleged autorefraction in the presbyopic population is associated with a myopic shift that can potentially lead to overestimation of myopic prevalence. This is an important factor in comparing population studies where cyclogleged autorefraction is used in contrast to non-cyclopleged autorefraction and subjective refraction.

Myopia prevention and therapy. The role of pharmaceutical agents. Japanese studies

In order to normalize the condition of pseudomyopia, the following can be summarized: One percent cyclopentolate was effective in 63%, and 0.4% tropicamide was effective in 59% of the cases. With a value of 68% after labetalol eye drops there were no significant differences in efficacy between this drug and the above cycloplegics. In subjects treated only with placebo, 4 out of 16 eyes, i.e. 25% were relieved. A significant difference (P less than 0.01) was found between the results with the above 3 drugs and placebo. On the other hand, the efficacy of 0.25% timolol (effect in 28%) and chemical X (effect in 37%) were not significantly different from the effect of placebo, though the results with chemical X encourage further trials. It can be postulated that by releasing an abnormal tension cycloplegics reduce the myopic condition. Regarding the hypotensive action of beta-adrenergic blockers on intraocular pressure, it presumably depends mainly on inhibition of secretion in the ciliary body. The fact that labetalol appeared effective, and timolol not, in treatment trials of slight myopia might imply that the mechanism behind an effect of labetalol on slight myopia is not merely a beta-adrenergic blocking action.

Screening for sight threatening diabetic retinopathy using non-mydriatic retinal camera in a primary care setting: to dilate or not to dilate?

OBJECTIVES

To evaluate three different strategies (without or with mydriasis) for community based screening for sight threatening diabetic retinopathy (STDR).

DESIGN

A masked cross-sectional comparative study.

SETTING

Primary care centre.

PARTICIPANTS

216 type-1 and type-2 diabetic patients (432 eyes).

INTERVENTIONS

Screening for STDR was performed with the Topcon CRW6S non-mydriatic camera (NMC), compared with the grading of the seven-field standard stereoscopic photographs, 30 degrees field photographs with mydriasis as the gold standard method. Three fields were studied: Field 1 centred on the macula; field 2 centred on the disc and the macula and field 3 centred on the disc, on the macula and temporal upper to the macula all without and with mydriasis.

MAIN OUTCOME MEASURES

Sensitivity and specificity of screening method and prevalence of STDR. Strategies: field 1 (macular), addition of field 2 (nasal), addition of field 3 (superior temporal) all without and with mydriasis.

RESULTS

The prevalence of STDR was 14.3%. When screening without mydriasis is performed, the percentage of referred patients increases from 14% (STDR) to almost 33% because of ungradable photographs. Sensitivity of detection of STDR by NMC using single field with mydriasis was 82% (95% confidence interval 72-92%) and without mydriasis 67% (54-80%). Specificity was 99% (97-100%) for single field with mydriasis and 99% (98-100%) without mydriasis. Sensitivity of detection using two fields with mydriasis was 95% (89-100%); without mydriasis (54-80%), slightly better than single field with mydriasis (72-92%). Specificity was similar.

CONCLUSIONS

Screening for STDR with NMC can be performed effectively with one non-stereoscopic retinal photograph per eye with mydriasis using tropicamide 0.5%. Screening without mydriasis increases the number of patients to be referred.

The effect of pupil dilation on driving vision in Canada

BACKGROUND

To determine whether there is a clinically significant reduction in visual acuity (VA) or contrast sensitivity (CS), with and without glare, following examination with pupil dilation in patients currently driving.

METHODS

From November 1, 2004, to February 28, 2005, 105 consecutive patients were assessed in our institution. The better eye was assessed pre- and post-dilation with and without glare administered through the Brightness Acuity Tester. VA was assessed using the Early Treatment in Diabetic Retinopathy Study (ETDRS) and Snellen charts. CS was measured using the Vistech VCTS 6500 Chart.

RESULTS

With no glare, there was a mean reduction of 4.8 letters read from the ETDRS chart following dilation (p < 0.001). With glare, there was a mean reduction of 7.1 letters (p < 0.001). Compared with patients with initial VA of 20/20, patients presenting with a Snellen VA of 20/25 to 20/40 had a 9.75 relative risk of postdilation VA worse than 20/40, whereas patients with initial VA of 20/40 had a 19.8 relative risk of postdilation VA worse than 20/40. With the addition of glare, these relative risks increased to 13.9 and 28.8, respectively. Without glare, there was a significant reduction in CS after dilation at spatial frequencies of 2.0, 4.0, and 6.0 cycles/degree (p = 0.014, p < 0.001, and p < 0.001, respectively). With glare, there was a greater reduction in CS at these 3 spatial frequencies (p < 0.001 for all).

INTERPRETATION

There is a significant reduction in VA and CS after dilation that is further confounded by the effect of glare. This reduction may limit some patients from driving after dilation.

Arousal and the pupil: why diazepam-induced sedation is not accompanied by miosis

RATIONALE

There is a close relationship between arousal and pupil diameter, decrease in the level of arousal being accompanied by constriction of the pupil (miosis), probably reflecting the attenuation of sympathetic outflow as sedation sets in. Paradoxically, sedation induced by benzodiazepines is not accompanied by miosis.

OBJECTIVE

The objective of this study was to examine the hypothesis that diazepam may attenuate both the sympathetic and the opposing parasympathetic outflow to the iris, which may mask the miosis. Dapiprazole (sympatholytic) and tropicamide (parasympatholytic) were applied topically, together with the cold pressor test (CPT), to manipulate the sympathetic/parasympathetic balance.

MATERIALS AND METHODS

Sixteen healthy male volunteers participated in four weekly sessions according to a balanced double-blind protocol. Diazepam 10 mg (two sessions) and placebo (two sessions), associated with either 0.01% tropicamide or 0.5% dapiprazole eyedrops, were administered orally. Pupil diameter, light and darkness reflexes and pupillary sleepiness waves were recorded with infrared video pupillometry, alertness was measured by critical flicker fusion frequency (CFFF) and visual analogue scales (VAS), blood pressure and heart rate by conventional methods. CPT was applied after post-treatment testing. Data were analysed by analysis of variance, with multiple comparisons.

RESULTS

Diazepam caused sedation (reduction in VAS alertness scores and CFFF, increase in sleepiness waves), dapiprazole had a sympatholytic and tropicamide a parasympatholytic effect on the pupil. Diazepam had no effect on pupil diameter and reflexes or their modifications by the antagonists. CPT increased pupil diameter, blood pressure and heart rate, and the increase only in systolic blood pressure was attenuated by diazepam.

CONCLUSIONS

Diazepam-induced sedation is not accompanied by any change in either the sympathetic or parasympathetic influence on the iris.

The muscarinic receptor antagonist tropicamide suppresses tremulous jaw movements in a rodent model of parkinsonian tremor: possible role of M4 receptors

RATIONALE

Nonselective muscarinic acetylcholine antagonists have been used for several years as antiparkinsonian drugs. However, there are at least five subtypes of muscarinic receptor (M1-5). Neostriatal M4 receptors have been implicated in aspects of motor function, and it has been suggested that M4 antagonists could be used as treatments for parkinsonism.

OBJECTIVE

Currently, there is a lack of highly selective M4 antagonists that readily penetrate the blood brain barrier. Thus, the present studies focused upon the effects of tropicamide, a muscarinic acetylcholine receptor antagonist with moderate binding selectivity for the M4 receptor subtype.

MATERIALS AND METHODS

Tremulous jaw movements were used as a model of parkinsonian tremor in these studies, and the effects of tropicamide were compared with those of the nonselective muscarinic antagonist atropine.

RESULTS

Tropicamide suppressed the tremulous jaw movements induced by the muscarinic agonist pilocarpine and the dopamine antagonist pimozide. Analysis of the dose-response curves indicated that tropicamide showed approximately the same potency as atropine for suppression of pilocarpine-induced jaw movements but was more potent than atropine on the suppression of pimozide-induced jaw movements. In contrast, atropine was more potent than tropicamide in terms of impairing performance on visual stimulus detection and delayed nonmatch-to-position tasks.

CONCLUSIONS

These studies demonstrate that tropicamide, which currently is used clinically for ophthalmic purposes, can exert actions that are consistent with antiparkinsonian effects. Moreover, the different pattern of effects shown by tropicamide compared to those of atropine on motor vs cognitive tasks could be due to the modest M4 selectivity shown by tropicamide.

Does prior instillation of a topical anaesthetic alter the pupillary mydriasis produced by tropicamide (0.5%)?

PURPOSE

It is common clinical practice to instill a topical anaesthetic prior to the instillation of a mydriatic agent into the eye. The main rationale for using the anaesthetic is to increase corneal permeability, so that more of the mydriatic agent reaches the receptor sites within the anterior chamber. It addition, as mydriatics generally cause stinging, prior use of an anaesthetic should reduce the degree of discomfort. The aim of the present study was to determine whether the efficacy of mydriasis produced by an antimuscarinic agent is enhanced by prior instillation of a topical anaesthetic.

METHOD

The study was performed using a double-masked protocol on 20 healthy young subjects. One drop of either proparacaine (proxymetacaine) (0.5%) or isotonic saline was instilled into the eye, followed by one drop of tropicamide (0.5%). Pupil diameter was measured using a customized photographic device at 0, 10, 20, 30 and 60 min following drug instillation. Additionally, subjects were asked to rate the degree of discomfort following the instillation of each drop on a scale from 0 (no discomfort) to 10 (agony).

RESULTS

There was no significant difference in either the rate of onset of mydriasis, or the maximum pupil diameter achieved between the two conditions. The mean change in pupil diameter produced by tropicamide after the instillation of saline or proparacaine was 2.31 and 2.28 mm, respectively. The mean discomfort scores following instillation of saline and proparacaine were 1.15 and 1.65, respectively, while mean discomfort scores following the instillation of tropicamide after saline or proparacaine were 4.00 and 0.85, respectively.

CONCLUSIONS

Instillation of a topical anaesthetic does significantly reduce the degree of discomfort produced by the instillation of tropicamide. However, it does not produce any significant increase in either the magnitude or rate of onset of mydriasis.

[Static vessel analysis in nonmydriatic and mydriatic images]

BACKGROUND

Static vessel analysis is a method to determine the diameter of retinal vessels in images of the ocular fundus. The suitability of non-mydriatic and mydriatic images for that method and the influence of mydriasis on the results were examined.

MATERIALS AND METHODS

In the prospective study, 30 eyes of 15 patients (10 women, mean age 51.6 +/- 13.2 years) were examined. At first, 3 images were taken of each eye with the retinal camera Topcon NW 200 (magnification 1). After pupil dilation with tropicamid eye drops, 3 more images were taken using the Topcon and 3 others using the system Visualis (IMEDOS, Jena/Germany, FF450plus, 535-561 nm, 30 degrees image, 1840 x 1360 pixel). The vessel diameters were measured with the software Vesselmap2 (IMEDOS). The investigator assigned vessels to arteries or veins and their diameters were calculated automatically by the software. There is the possibility to define the vessel edge manually in cases of a poor image quality. The calculation of the central retinal arterial and venous equivalent (CRAE, CRVE) as well as the arterio-venous ratio (AVR) were made according to the formula of Parr-Hubbard. Furthermore, the nasal retinal vessels > 60 microm were examined to estimate the influence of tropicamid on the vessel diameter.

RESULTS

Because of insufficient illumination and poor contrast in 21 % of the non-mydriatic images not all vessels could be detected automatically. Additionally, fewer vessels could be detected in 7 % of the non-mydriatic images compared to the mydriatic images. The average coefficient of variation of CRAE and AVR of each triplet of images was higher in non-mydriatic images (2.6 % and 3.2 %, respectively) than in mydriatic images of the Topcon (1.8 %; 2.3 %) and the FF 450 (1.7 %; 1.8 % ANOVA p < 0.05). No significant differences were found between the various examination methods for both the coefficient of variation of CRVE (1.9 %; 1.8 %; 1.7 %) and the average values of CRAE, CRVE and AVR. With regard to their diameters, the nasal retinal arteries and veins > 60 microm, were depicted sufficiently in all images, and only differed insignificantly between the three methods.

CONCLUSION

The quality of non-mydriatic images is often lower than that of mydriatic images. This fact can account for the high variance of measured parameters in the non-mydriatic images. The depiction of all relevant vessel segments is a precondition for the image-based analysis. An influence of the mydriasis caused by tropicamid on the retinal vessel diameters > 60 microm was not found.

Nonmydriatic screening for diabetic retinopathy by ultra-widefield scanning laser ophthalmoscopy (Optomap)

PURPOSE

To compare the diagnostic properties of a nonmydriatic 200 degrees ultra-widefield scanning laser ophthalmoscope (SLO) versus onsite mydriatic ophthalmologic examination for diabetic retinopathy.

METHODS

A consecutive series of 51 eyes of 51 patients with different levels of diabetic retinopathy (DR) was examined. Grading of diabetic retinopathy and macular edema obtained on stereoscopic dilated funduscopy by a retina specialist was compared against grading obtained from Optomap Panoramic200 SLO images. All SLOs were performed with an undilated pupil, and no additional clinical information was used for evaluation of the Optomap images by three independent, masked expert graders.

RESULTS

A total of five images (9.8%) were not gradable due to insufficient quality. Clinically 4 eyes had proliferative diabetic retinopathy (PDR), while 9 had none, 5 mild, 19 moderate and 14 severe nonproliferative diseases (NPDR). Of the gradable 46 images, a clinically significant macular edema (CSME) was present in 28 eyes clinically. On Optomap, all eyes with PDR were detected as being proliferative, and a sensitivity of 94% at a specificity of 100% was obtained for all graders to detect more than mild DR. Agreement between Optomap retinopathy grading and clinical assessment was good with unweighted kappas of 0.68, 0.68 and 0.51. Assessment of CSME yielded sensitivities of 93, 93 and 89% at specificities of 89, 72 and 83%.

CONCLUSIONS

The Optomap Panoramic200 nonmydriatic images are of sufficient quality to assess DR and CSME validly and therefore fulfill the basic requirements for telescreening programs.

Mist delivery of eye medication to the anterior segment

PURPOSE

To compare the mydriatic efficacies of mist and drop delivery of tropicamide 1.0%.

DESIGN

Randomized, masked, active, controlled clinical trial.

METHODS

One hundred subjects were randomized to receive small-volume (6 microl) mist administration of tropicamide 1.0% in one eye and either nothing or a conventional drop (30 microl) of the same solution in the fellow eye.

RESULTS

Comparing misted eyes with untreated eyes in the same subjects, the mean maximal increase in pupil diameter in the misted eyes was 2.02 mm and was 0.25 mm in the fellow eyes. The difference is statistically significant (P <or= .001) Comparing mist-treated eyes with drop-treated eyes in the same subjects, the mean maximal increase in pupil diameter in the misted eyes was 1.98 mm and was 2.11 mm in the drop-treated eyes. The difference was not statistically significant (P = .051).

CONCLUSIONS

Small-volume mist and conventional drop delivery of tropicamide 1.0% were shown to be similar in mydriatic effectiveness.

Effects of adrenergic and cholinergic antagonists on diameter of nasolacrimal drainage system

BACKGROUND

To determine the effect of an adrenergic and a cholinergic antagonist on the diameter of the lumen of the nasolacrimal drainage system.

METHODS

The asymptomatic side of 38 patients (29 women, nine men) with unilateral stenosis/obstruction of the nasolacrimal drainage system was studied. The tear meniscus height (TMH) of the asymptomatic side was normal, and the lacrimal drainage system was patent as revealed by dacryocystography. The nasolacrimal drainage system of the asymptomatic side was infused with 100 mul of 0.01% bunazosin hydrochloride, a selective alpha-1 adrenergic antagonist, or 100 mul of 0.4% tropicamide, a muscarinic and cholinergic antagonist. Dacryocystography was performed to determine the diameter of the lumen of the nasolacrimal drainage system before and after the antagonists.

RESULTS

Bunazosin reduced the diameter of the lumen significantly, and the changes were more marked in the nasolacrimal duct (NLD), especially the middle and the lower regions. The diameter of the lumen of the lacrimal sac was not changed significantly. In contrast, tropicamide did not cause any significant change in the diameter of the lumen of the nasolacrimal drainage system.

CONCLUSIONS

The alterations of the size of the lumen of the nasolacrimal drainage system, especially the NLD, by an adrenergic antagonist suggest that the lumen diameter is under continuous sympathetic tone, and the parasympathetic tone is weak.

The Association between Retinal Vascular Network Geometry and Cognitive Ability in an Elderly Population

PURPOSE

To test the hypothesis that parameters of retinal vascular network geometry are significantly associated with cognition.

METHODS

Three hundred twenty-one community-dwelling, surviving participants in the Scottish Mental Survey of 1932 from the Lothian region of Scotland (Lothian Birth Cohort 1921; all born in 1921 and aged approximately 83 when tested) underwent fundus photography and the following psychometric tests: Wechsler Logical Memory, Verbal Fluency, and Raven's Standard Progressive Matrices. In addition, a general cognitive ability score (g) was obtained from these three correlated tests of cognition. The following parameters of the retinal vascular network geometry were measured: central retinal arterial and venular equivalents (CRAE and CRVE, respectively), arteriovenous ratio (AVR), suboptimality of the median branching coefficient (BC), and median angle of the five most proximal arteriolar bifurcations. General linear modeling (GLM; analysis of covariance [ANCOVA]) was used to measure associations, with gender, APOE e4 status, presence of diabetes, smoking status (current, ex-, or never), and history of cerebrovascular disease as fixed factors and the following covariables: IQ at age 11, logMAR (logarithm of the minimum angle of resolution) near visual acuity of the better-seeing eye, years of full-time formal education, occupational social class category, systolic and diastolic blood pressure, and alcohol units per week.

RESULTS

Deviation of the median BC from optimality was significantly associated with general cognitive ability (g) (eta(2) = 0.034, P = 0.02) and verbal fluency (eta(2) = 0.037, P = 0.01), whereas deviation of the angle at arteriolar bifurcations from optimality was significantly associated with logical memory (eta(2) = 0.026, P = 0.03). CRAE, CRVE, and AVR did not contribute significantly to any cognitive test scores. Conclusions The association of suboptimal retinal vascular network geometry and cognition was shown in this study. It supports the concept that the retinal microvasculature acts as a surrogate marker for the cerebral microvasculature.

Effects of three mydriatic drug regimens on pupil size in rhesus (Macaca mulatta) and African green monkeys (Chlorocebus aethiops)

BACKGROUND

Human mydriatric drug use in non-human primates (NHPs) has been documented but not quantified and compared for effectiveness. The objective of this study was to determine which drug regimen provided the most effective and consistent mydriatic effect for ophthalmologic examinations and other procedures. Secondary objectives were to determine average time to maximum dilation and whether species differences existed.

METHODS

Twelve rhesus and 12 African green monkeys were randomly assigned to one of six treatment combinations to test the mydriatic effects of three drug regimens: (1) tropicamide 1% (T); (2) tropicamide 1% and phenylephrine hydrochloride 2.5% (TP); and (3) tropicamide 1%, phenylephrine HCL 2.5% and cyclopentolate 1% (TPC). Left and right eyes of each monkey received a different drug regimen, depending on random assignment.

RESULTS

TPC showed a significantly larger mydriatic response in both species than T alone. Average time to maximum dilation with all three drug regimens was 50-60 minutes. Rhesus had a larger response to the mydriatic drug regimens than the African green monkeys.

CONCLUSIONS

The TPC regimen had the largest and longest lasting mydriatic effect in both species.

Cycloplegic effect of 0.5% tropicamide and 0.5% phenylephrine mixed eye drops: objective assessment in Japanese schoolchildren with myopia

PURPOSE

To evaluate the cycloplegic effect of mixed eye drops containing 0.5% tropicamide and 0.5% phenylephrine in myopic children, and to determine whether their efficacy was associated with their clinical characteristics.

METHODS

Eighty-one myopic children (age, mean +/- SD, 11.0 +/- 1.5 years; mean spherical equivalent refractive error, -4.27 +/- 1.41 D; range, -1.57 to -8.66 D) were recruited. One drop of Mydrin-P was administered to each eye twice, with an interval of 5 min between. Twenty-five minutes after the second drop, accommodative responses were measured with an open-view autorefractometer, while the subject was encouraged to accommodate by binocularly looking at a Maltese cross located at a distance of 33 cm. The difference between the refractive reading and that obtained with a Maltese cross at 500 cm was regarded as residual accommodation (RA). The repeatability of this measurement was also evaluated.

RESULTS

The mean RA was 0.21 +/- 0.29 D (range, -0.31 to 0.99 D). There was no association in RA between the right and left eyes, between RA and age, or between RA and sex, but RA was weakly correlated with refractive error (r = 0.274, P = 0.019). The intersubject difference found in RA can be explained mostly by the extent of repeatability (+/-0.71 D).

CONCLUSION

The insignificant magnitude of RA indicated that the mixed eye drop is an acceptable and useful cycloplegic agent in Japanese schoolchildren with a wide range of myopic refractive errors.

Cost-Effectiveness of Cycloplegic Agents: Results of a Randomized Controlled Trial in Nigerian Children

PURPOSE

To compare the cost and effectiveness of three cycloplegic agents among Nigerian children.

METHODS

Two hundred thirty-three children aged 4 to 15 years attending outpatient eye clinics in Nigeria were randomized to (1) 1% cyclopentolate, (2) 1% cyclopentolate and 0.5% tropicamide, or (3) 1% atropine drops in each eye (instilled at home over 3 days). Ten children were lost to follow-up, nine from the atropine group. An optometrist measured the residual accommodation (primary outcome), dilated pupil size, pupil response to light, and self-reported side effects (secondary outcomes). Caregivers were interviewed about costs incurred due to cycloplegia (primary outcome). The incremental cost effectiveness ratios (ICERs) were calculated as the difference in cost divided by the difference in effectiveness comparing two agents. The 95% confidence intervals (CI) for ICERs were estimated through bootstrapping.

RESULTS

The atropine group had significantly lower mean residual accommodation (0.04 +/- 0.01 D [SE]), than the combined regimen (0.36 +/- 0.05 D) and cyclopentolate (0.63 +/- 0.06 D) groups (P < 0.001). Atropine and the combined regimen produced better results for negative response to light and dilated pupil size than cyclopentolate. Atropine was more expensive, but also more effective, than the other agents. The ICER comparing atropine to the combined regimen was 1.81 (95% CI = -6.31-15.35) and compared to cyclopentolate was 0.59 (95% CI = -3.47-5.47). The combined regimen was both more effective and less expensive than cyclopentolate alone.

CONCLUSIONS

A combination of cyclopentolate and tropicamide should become the recommended agent for routine cycloplegic refraction in African children. The combined regimen was more effective than cyclopentolate, but not more expensive, and was preferable to atropine, since it incurred fewer losses to follow-up.

Assessment of bacterial contamination of three multidose ophthalmic solutions

OBJECTIVE

To investigate the frequency of bacterial contamination of multidose proparacaine hydrochloride, tropicamide, and eyewash bottles used in veterinary ophthalmology examination rooms during normal operating procedures.

METHODS

Three representative bottles each of proparacaine hydrochloride, tropicamide, and purified water eye wash were opened at the same time, numbered, and placed into small animal examination rooms. Doctors, students and technicians who were using the solutions were blinded to the study. Aerobic cultures were obtained at the time of opening (time 0), at 1 week (time 1), and at 2 weeks after opening (time 2) the bottles. The sites cultured included a drop of each solution, the inside of the bottle cap, the tip of the bottle, and the bottle threads and medication residue found in these threads.

RESULTS

Aerobic cultures of tropicamide and proparacaine had no growth of bacteria from any of the evaluated sites. Staphylococcus epidermidis was cultured from the tip of one bottle of eye wash after 1 week.

CONCLUSIONS

We conclude that proparacaine, tropicamide, and eyewash solutions used in veterinary examination rooms are adequately preserved for use in ophthalmic examination. They have a low level of bacterial contamination 1 or 2 weeks after opening when used and stored according to the recommendations of the product manufacturers and previous studies.

[Influence of intraoperative pupil diameter and nuclear grade due to complications during Aqualase phacoemulsification]

PURPOSE

The aim of this study was to make an evaluation of the frequency of intraoperative complications during Aqualase phacoemulsification and correlate it to different intraoperative pupil diameters and nuclear grades.

METHODS

Aqualase phacoemulsification was performed in 23 eyes without retinal or optic disc pathology in 23 unselected patients (15 women and 8 men) who underwent out-patient cataract surgery. Nuclear grade, intraoperative pupil diameters and complications were recorded. The correlation of intraoperative complications with intraoperative pupil diameter and nuclear grade was determined using "Fisher's exact" test.

RESULTS

The average age of our patients was 70.3 (+/- 12.5) years, the mean best spectacle-corrected visual acuity (BSCVA) preoperatively was 0.39 (+/- 0.15) and the mean BSCVA postoperatively was 0.79 (+/- 0.13). The mean aqua time was 3.11 s (+/- 1.55 s) with maximum nuclear sclerosis of up to grade 3 (mean nuclear sclerosis 1.9). The aqua time correlated with the nuclear sclerosis (r = 0.90). The mean intraoperative pupil diameter was 7.2 (+/- 0.7) mm. In 2 of 3 patients with an intraoperative pupil diameter of 6 mm, iris touch occurred intraoperatively. There were no other intra- or postoperative complications. The frequency of iris touch was statistically significantly higher for reduced pupil diameters (p = 0.01). The nuclear grade with a maximum of 3 was without statistical significance to iris touch frequency (p > 0.05).

CONCLUSIONS

The number of iris traumas is significantly higher when the intraoperative pupil diameter is reduced. The iris should be protected in these cases. A prospective, randomised study should be performed to compare the number of intraoperative complications between ultrasound and Aqualase phacoemulsification.

Randomised controlled single-blind study of conventional versus depot mydriatic drug delivery prior to cataract surgery

BACKGROUND

A prerequisite for safe cataract surgery is an adequately dilated pupil. The authors conducted a trial to assess the efficacy (in terms of pupil diameter) of a depot method of pre-operative pupil dilatation, as compared with repeated instillations of drops (which is time-consuming for the nursing staff and uncomfortable for the patient).

METHODS

A prospective randomised masked trial was conducted comprising 130 patients with no significant ocular history undergoing elective clear corneal phacoemulsification. 65 patients had mydriatic drops (Tropicamide 1%, Phenylephrine 2.5%, Diclofenac sodium 0.1%) instilled prior to surgery, 65 had a wick soaked in the same drop mixture placed in the inferior fornix. Horizontal pupil diameters were recorded on a millimetre scale immediately prior to surgery.

RESULTS

There was no significant difference in pupil size between the two groups (p = 0.255, Student's t-test).

CONCLUSION

There was no significant difference between the mydriasis obtained with the depot system compared with conventional drop application. Use of a depot mydriatic delivery system appears to be a safe and efficient method of drug delivery.

TRIAL REGISTRATION

International Standard Randomised Controlled Trial Number Register ISRCTN78047760.

Pharmacodynamics of a new ophthalmic mydriatic insert in healthy volunteers: potential alternative as drug delivery system prior to cataract surgery

Cataract surgery requires a satisfactory degree of mydriasis throughout the entire operation. A phase I, open-labelled, randomised, cross-over trial was conducted in 18 healthy volunteers to compare mydriasis obtained with subsequent administration of phenylephrine 10% and tropicamide 0.5% eyedrops or a new insoluble-matrix retropalpebral ophthalmic insert containing 5.38 mg phenylephrine and 0.28 mg tropicamide. Phenylephrine serum concentrations were measured over 6 hr following each treatment administration. Secondary end-points included cardiovascular, general and local tolerance and quantification of bacterial colonisation of the conjunctiva and the cultured insert, respectively. When normalized to the pupil diameter after conventional treatment, the diameter achieved with the insert was 1.13 (95% confidence interval, 0.94-1.48, P=0.38). Moreover, standard eye drops provided faster effective mydriasis than the insert, starting 30 min. as compared to 90 min. upon treatment administration (P<0.01, repeated-measures ANOVA). Phenylephrine concentrations remained almost undetectable for both treatments and no change in heart rate or blood pressure were observed throughout the study. Only three superficial punctuate keratitis were diagnosed with the insert and two with the eye drops. No significant bacterial contamination of conjunctiva swab and cultured insert was observed. The new insoluble-matrix retropalpebral ophthalmic mydriatic insert produced similar but delayed effective and prolonged mydriasis as compared to the standard delivery system. In addition to its potential usefulness in patients undergoing cataract surgery, such new ophthalmic delivery system may be an advantage in children who need to undergo fundus photography due to the single administration and excellent tolerance as well.

Single dose of 1% tropicamide and 10% phenylephrine for pupil dilation

OBJECTIVE

To compare the efficacy of pupil dilation between a single dose and three doses of 1% tropicamide and 10% phenylephrine for binocular indirect ophthalmoscopy.

MATERIAL AND METHOD

A prospective randomized double-blind clinical controlled trial was conducted. All patients underwent the binocular indirect ophthalmoscopy and met the inclusion criteria were randomized into two groups using block randomization. Group A received a single dose of 1% tropicamide and 10% phenylephrine eye drops, and Group B received three doses of the same drugs. The primary outcome was the horizontal pupil diameter measured by slit-lamp biomicroscope (Haag-Streit model 900) before and at 10, 15, 20, 25 and 30 minutes after eye drop instillation. The clinical equivalence of the efficacy of pupil dilation between the two groups was defined as the difference of less than or equal to 1 mm (-1 mm to + 1 mm).

RESULTS

Eighty patients (160 eyes) were randomized into 40 patients (80 eyes) in group A and 40 patients (80 eyes) in group B. The mean pupil sizes at baseline of group A were 3.51 +/- 0.63 mm in the right eye and 3.39 +/- 0.67 mm in the left eye. Those in group B were 3.61 +/- 0.67 mm in the right eye and 3.66 +/- 0.72 mm in the left eye. The mean pupil diameters at 30 minutes of group A were 7.34 +/- 0.51 mm in the right eye and 7.41 +/- 0.56 mm in the left eye, whereas those of group B were 7.49 +/- 0.45 mm in the right eye and 7.51 +/- 0.40 mm in the left eye. The mean difference of the pupil size between the two groups was 0.15 mm (p = 0.175) in the right eye and 0.l0 mm (p = 0.362) in the left eye. The 95% confidence intervals of the difference in pupil size were -0.36 to 0.07 mm in the right eye and -0.32 to 0.12 mm in the left eye.

CONCLUSION

The 95% confidence interval of the difference in pupil size lay entirely within the range of equivalence. The single dose of 1% tropicamide and 10% phenylephrine was clinically equivalent to the three doses of the same drugs.

Pupil dilation using a pledget sponge: a randomized controlled trial

BACKGROUND

To show that a pledget soaked in mydriatics and placed in the lower conjunctival fornix is as effective as drops in providing mydriasis for cataract surgery.

METHODS

A randomized, masked, controlled trial of 56 patients assigned to either a pledget group (n=25) or a control eye drops group (n=31) was carried out. Controls had the routine practice of repeated topical mydriatic drops: tropicamide, phenylepherine and atropine. The trial group had a 3-mm pledget trimmed, soaked in mydriatics and placed in the inferior fornix for 20 min. Pupil diameter was measured using a photographic technique with a standard scale shown in each picture. Two masked observers measured the pupils using the scale of the ruler in the developed photograph. All patients completed a 0-10 stinging score prior to surgery.

RESULTS

There were no complications. The mean pupil diameter in the control group was 7.23 (6.91-7.94 95% confidence intervals [CI]) and 7.44 (6.96-7.92 95% CI) in the pledget group. There was no statistically significant difference in pupil diameter between the two groups: difference between means 0.21 (-0.32 to 0.75 95% CI) and Student's t-test of the difference between means (t=0.8 and two-tailed) probability P=0.43. There was no significant difference in the stinging scores: Mann-Whitney test P=0.69.

CONCLUSION

The use of a pledget cellulose sponge to deliver mydriatics prior to cataract surgery is as effective as the conventional method of repeated drop administration and was not associated with any adverse effects.

Higher Order Ocular Aberrations in Eyes With Myopia in a Chinese Population

PURPOSE

To describe the characteristics of higher order ocular aberrations of adult Chinese eyes with myopia.

METHODS

Higher order aberrations in consecutive right eyes of 166 Chinese patients with myopia who enrolled for preoperative assessment for LASIK were retrospectively reviewed. Wavefront aberrations were measured with the Bausch & Lomb Zywave over a 6-mm dilated pupil. The correlations between higher order aberrations and myopia, astigmatism, and age, respectively, were analyzed.

RESULTS

Mean patient age was 32.1 +/- 6.2 years, the mean refractive error was sphere -5.23 +/- 1.79 diopters (D) and cylinder -1.29 +/- 0.98 D. The mean of the total higher order root-mean-square (RMS) (third to fifth order) was 0.49 +/- 0.16 microm. Third-order RMS was largest (mean 0.37 +/- 0.16 microm), followed by fourth-order RMS (mean 0.29 +/- 0.11 microm). For individual higher order Zernike coefficients, spherical aberration (C4(0)) predominated with a mean of 0.23 +/- 0.14 microm. No correlation was found between total higher order RMS and myopia or between total higher order RMS and age. Small but statistically significant relationships were found in the following groups: age and vertical primary coma (C3(-1))(r=-0.206, P=.008); age and spherical aberration (C4(0)) (r=0.196, P=.012); and myopia and horizontal trefoil (C3(3)) (r=-0.158, P=.042).

CONCLUSIONS

Higher order aberrations varied among individuals with myopia. Third-order RMS was the predominant higher order aberration. Spherical aberration and vertical primary coma increased slightly with age. Our study helps establish ocular aberration standards for Chinese refractive surgery candidates.

Effects of mydriatics on intraocular pressure and pupil size in the normal feline eye

OBJECTIVE

To determine the effect of various mydriatics (1% atropine, 1% cyclopentolate, 0.5% tropicamide, 10% phenylephrine) on intraocular pressure (IOP) and pupil size (PS) in normal cats.

ANIMALS STUDIED

The mydriatics were tested in 10 adult ophthalmoscopically normal European Domestic Short-haired cats. Procedure Single-dose drug studies were divided into placebo (vehicle of phenylephrine), 10% phenylephrine, 0.5% tropicamide, 1% cyclopentolate and 1% atropine. After measurement of IOP and pupil size (PS) at 8 a.m. on the first day, one drop of the tested drug was applied to one randomly selected eye. The IOP and PS were measured for a minimum of 36 h until the pupil returned to pretest size.

RESULTS

Ten per cent phenylephrine had no significant effect on IOP, and the effect on the pupil size was minimal (<or= 1 mm difference). One per cent atropine showed a maximal mean difference of 4.3 mmHg +/- 4.1 mmHg in IOP compared to the untreated eye. These differences were statistically significant at 1, 3, 6, 12 and 16 h post-treatment. At 1, 1.5 and 2 h after unilateral application of 1% cyclopentolate, the IOP in the treated eye was significantly higher than the IOP in the untreated eye with a maximal mean difference of 4.1 mmHg +/- 4.5 mmHg. With 0.5% tropicamide, IOP of the treated eye was significantly higher than IOP of the untreated eye at 1 and 1.5 h after treatment with a maximal mean difference of 3.5 mmHg +/- 3.3 mmHg. One per cent atropine caused the greatest increase in IOP, followed by 1% cyclopentolate and 0.5% tropicamide. The dilating effect of atropine, cyclopentolate and tropicamide lasted longer than the effect on intraocular pressure.

CONCLUSIONS

The parasympatholytics 1% atropine, 1% cyclopentolate and 0.5% tropicamide caused a statistically significant elevation of IOP and produced mydriasis in the treated eye in normal cats, while the sympathomimetic 10% phenylephrine had no significant effect on IOP or pupil size.

A combination solution for routine pupillary dilation

BACKGROUND

This study investigated the ability of a combination drop containing reduced concentrations of tropicamide and phenylephrine to produce pupillary dilation adequate for routine fundoscopy.

METHODS

One eye of each subject (N = 28; age range, 21 to 40 years; median, 23 years) was dilated with 1 drop of a solution containing 0.5% tropicamide and 2.5% phenylephrine (0.5T/2.5P). The other eye was dilated with 1 drop of either of 2 mixtures: 0.5% tropicamide and 1.25% phenylephrine (0.5T/1.25P, N = 15; median age, 23 years), or 0.25% tropicamide and 1.25% phenylephrine (0.25T/1.25P, N = 13; median age, 23 years). A topical anesthetic was administered before instilling the mydriatic agents. Pupil diameter was measured from a flash photograph taken every 15 minutes for 3 hours. There was no significant difference in pupil diameter between eyes dilated with the 0.5T/1.25P test solution and the 0.5T/2.5P control solution for the first 75 minutes after instillation (P = 0.41). All pupils reached their maximum diameter 60 minutes after drop instillation; where no significant difference was observed between the 3 mydriatic solutions (P = 0.81). All pupils were at least 7 mm in diameter 30 minutes after drop instillation, and this size was maintained for at least another 75 minutes for all solutions.

CONCLUSIONS

Combination preparations of reduced concentrations of tropicamide and phenylephrine can produce clinically adequate mydriasis.