From the Guidelines
Mydriatic agents should be avoided if there is iridocorneal touch due to the risk of worsening angle closure and increasing intraocular pressure. When the iris is already touching the cornea, dilating the pupil with mydriatics can cause the peripheral iris to bunch up and further block the trabecular meshwork, potentially precipitating an acute angle closure crisis 1. Instead, the primary management should focus on reducing intraocular pressure with medications like topical beta-blockers, alpha-2 agonists, or carbonic anhydrase inhibitors, followed by definitive treatment such as laser peripheral iridotomy to create a bypass channel for aqueous humor.
Some key points to consider in the management of iridocorneal touch include:
- The use of systemic hyperosmotic agents to achieve a rapid decrease in IOP in the setting of AACC 1
- Corneal indentation performed with a four-mirror gonioscopic lens, cotton-tipped applicator, or tip of a muscle hook to help break pupillary block 1
- Laser iridotomy as the preferred surgical treatment due to its favorable risk-benefit ratio 1
- The potential need for alternative treatments such as LPI, paracentesis, and incisional iridectomy if laser iridotomy is not possible or if the AACC cannot be medically broken 1
It's also important to note that miotic agents like pilocarpine may be ineffective in cases of secondary pupillary block due to intraocular gas, oil, or vitreous, or if the IOL or crystalline lens is blocking the pupil, and in these cases, mydriatics may be more effective 1. However, the primary goal should be to reduce IOP and address the underlying anatomical problem, rather than temporarily manipulating pupil size with medications that could worsen the condition.
In terms of specific treatment options, the following may be considered:
- Topical beta-blockers (e.g. timolol 0.5%, one drop twice daily) 1
- Alpha-2 agonists (e.g. brimonidine 0.1-0.2%, one drop three times daily) 1
- Carbonic anhydrase inhibitors (e.g. dorzolamide 2%, one drop three times daily) 1
- Systemic hyperosmotic agents (e.g. mannitol or glycerol) to rapidly decrease IOP in the setting of AACC 1
From the Research
Iridocorneal Touch and Mydriatic Agents
- Iridocorneal touch is a condition where the iris comes into contact with the cornea, which can be a sign of iridocorneal endothelial syndrome 2, 3, 4.
- Mydriatic agents, such as tropicamide and phenylephrine, are used to dilate the pupils for diagnostic purposes, but their use in cases of iridocorneal touch is not well established.
Effects of Mydriatic Agents on Iridocorneal Touch
- There is limited research on the specific effects of mydriatic agents on iridocorneal touch, but studies suggest that dilation can cause changes in the anterior chamber angle and iris surface 2, 4.
- The use of mydriatic agents, such as tropicamide and phenylephrine, can cause a decrease in radial peripapillary capillary density, which may be relevant in cases of iridocorneal touch 5.
Clinical Considerations
- The diagnosis and management of iridocorneal endothelial syndrome, which can cause iridocorneal touch, typically involve a combination of clinical examination, imaging techniques, and surgical intervention 3, 4.
- The use of mydriatic agents in cases of iridocorneal touch should be approached with caution, as it may exacerbate the condition or interfere with diagnostic procedures 2, 5.