Tropicamide
Anton C. de Groot in Monographs in Contact Allergy, 2021
Tropicamide is a synthetic muscarinic antagonist with actions similar to atropine and with an anticholinergic property. Upon ocular administration, tropicamide binds to and blocks the muscarinic receptors in the sphincter and ciliary muscle in the eye. This inhibits the responses from cholinergic stimulation, producing dilation of the pupil and paralysis of the ciliary muscle. Tropicamide in eye drops is indicated to induce mydriasis and cycloplegia in diagnostic procedures, such as measurement of refractive errors and examination of the fund us of the eye (1).
Ophthalmic Emergencies
Anthony FT Brown, Michael D Cadogan in Emergency Medicine, 2020
The following preparations are referred to in the text: Antibiotic drops: 0.5% chloramphenicol solution, two drops every 2–3 h.Antibiotic ointment: 1% chloramphenicol ointment, one application to the lower lid conjunctival sac every 4 h, or at night (if drops are used during the day).Local anaesthetic: 1% amethocaine (tetracaine) solution or 0.4% oxybuprocaine solution, one or more drops as required. – The patient must then wear a protective eye pad for 1–2 h until corneal sensitivity returns– Never allow the patient to take the drops home.Fluorescein corneal stain: fluorescein sodium strips, or 2% fluorescein solution (do not use with soft contact lenses).Short-acting mydriatic and cycloplegic dilating drops to examine the fundus: 1% tropicamide, two drops repeated after 15 minutes if necessary (do not use in patients with narrow anterior chambers to avoid precipitating glaucoma).Cycloplegic to paralyse the ciliary body: 1% cyclopentolate two drops lasts 6–24 h, or 2% homatropine two drops can last from 8–12 h to 1–2 days.Miotic to constrict the pupil or reverse a mydriatic: 2% pilocarpine one or two drops.
Answers
John D Firth, Professor Ian Gilmore in MRCP Part 2 Self-Assessment, 2018
All of the preparations listed can be used to dilate the pupils, but tropicamide (0.5% for children, 1% for adults) is best for diagnostic purposes, dilating the pupil for two to four hours by blocking the parasympathetic terminals in the papillary constrictor muscle. Cyclopentolate works in a similar manner but lasts for six to eight hours.
Plasma angiogenesis and oxidative stress markers in patients with diabetic retinopathy
Published in Biomarkers, 2020
Bhaskar Gaonkar, Krishnananda Prabhu, Pragna Rao, Asha Kamat, Krishna Rao Addoor, Muralidhar Varma
A total of 518 subjects aged 45–75 years and, attending the outpatient department of ophthalmology, Kasturba hospital Manipal were recruited for this study. Patients with cancer, liver disease, kidney disease, myocardial infarction, retinopathy patients who had undergone laser or anti-VEGF therapy and subjects with signs of active infections and ocular diseases other than DR were excluded from the study. Tropicamide was used for pupillary dilatation. Retinal examination was conducted by an ophthalmologist and retinopathy was confirmed by retinal fundus photographs. On the basis of the characteristics observed in the retinal fundus photographs and the ‘International Diabetic Retinopathy Disease Severity Scale’, the subjects were grouped (Ciulla et al.2003). Thus, the subjects were categorized into four groups as normal (n = 148), type 2 diabetes without retinopathy (DNR) (n = 148), non-proliferative DR (NPDR) (n = 148) and proliferative DR (PDR) (n = 74) (Figure 1).
The prophylactic effect of betaxolol 0.5% versus brimonidine 0.2% on IOP elevation after Nd:YAG laser posterior capsulotomy
Published in Clinical and Experimental Optometry, 2022
Navid Elmi Sadr, Elnaz Saber, Fatemeh Paknazar
In this study, IOP was measured 1 hour before performing laser posterior capsulotomy and 4 hours after it. The age of the patients, number of laser shots, total laser energy, and baseline mean IOP were not significantly different between the study groups. Tropicamide 1%, which is a cycloplegic drug, was used to dilate the pupil before laser treatment. It is shown that cycloplegics can temporarily increase IOP by decreasing trabecular outflow. Tropicamide has a duration of action approximately 4–6 hours.25 On the other hand, brimonidine and betaxolol have peak IOP reduction 2 hours after instillation.22 The time needed to reach peak effect of brimonidine and betaxolol, in addition to the time needed for effects of tropicamide to wear off, are not as the same in every patient. By measuring IOP at different time intervals after laser application, the confounding effect of inter-individual variations can be minimised. COVID-19 pandemic was the main limitation for the researchers to do multiple ocular examination. In accordance with health and safety protocols, keeping the patients in the clinic for an extended time of observation and examination was not allowed. For this reason, IOP was measured at one time point (4 hours after laser application). There were three reasons to choose this time point. First, the maximum increase in IOP occurs within 3–4 hours after the laser treatment.3–6,12,15,20 Second, the maximum IOP lowering effect of the drugs has appeared, and third, the mydriatic effect of tropicamide has diminished considerably at this time point.
Diurnal Variation and Effects of Dilation and Sedation on Intraocular Pressure in Infant Rhesus Monkeys
Published in Current Eye Research, 2023
Krista M. Beach, Li-Fang Hung, Linjiang Lou, Lisa A. Ostrin
In addition to sedation, many protocols in animal models require instillation of topical mydriatic agents. For example, measurement of refraction, biometry, and retinal imaging requires pupil dilation and cycloplegia. In our lab, we typically use tropicamide because it provides sufficient pupil dilation and cycloplegia while being relatively short acting. However, administration of tropicamide has also been shown to affect IOP in some species. While tropicamide was shown not to affect IOP in sheep or humans,28,29 tropicamide elevated IOP in cats and dogs.30–34 Additionally, in cats, the effects of tropicamide on IOP were shown to decrease with age.33 The effects of tropicamide on IOP and interactions with age in rhesus monkeys are unknown.
Related Knowledge Centers
- Blurred Vision
- Muscarinic Antagonist
- Mydriasis
- Ocular Hypertension
- Photosensitivity
- Psychosis
- Pregnancy
- Eye Examination
- Fundus
- Ophthalmic Drug Administration