Which anticonvulsant has ocular side effects of mydriasis, increased IOP, and cycloplegia?

Which anticonvulsant has ocular side effects of mydriasis, increased IOP, and cycloplegia?

• A. Topiramate
• B. Luminal (Phenobarbital)
• C. Dilantin (Phenytoin)
• D. Carbamazepine

Answer: (B)

Understanding how anticonvulsants can affect the eye starts with recognizing that some drugs can alter autonomic control in the eye, leading to pupil changes and accommodation issues, and in rare cases, affecting intraocular pressure. Phenobarbital has been reported in some sources to cause ocular reactions such as pupil dilation (mydriasis), increased intraocular pressure, and cycloplegia (loss of the eye’s ability to accommodate). This combination points to a disruption of normal autonomic regulation within the eye and, in susceptible individuals, can manifest as the triad described. While these ocular effects are uncommon, they are more aligned with this drug’s potential ocular side-effect profile than with the other anticonvulsants listed, which typically cause different eye findings (for example, diplopia or nystagmus) rather than the specific trio of mydriasis, elevated IOP, and cycloplegia. So, recognizing this pattern helps identify phenobarbital as the anticonvulsant associated with that particular set of ocular adverse effects. If any patient on anticonvulsants develops sudden eye pain, visual changes, or redness, urgent ophthalmologic evaluation is warranted.

Understanding how anticonvulsants can affect the eye starts with recognizing that some drugs can alter autonomic control in the eye, leading to pupil changes and accommodation issues, and in rare cases, affecting intraocular pressure.

Phenobarbital has been reported in some sources to cause ocular reactions such as pupil dilation (mydriasis), increased intraocular pressure, and cycloplegia (loss of the eye’s ability to accommodate). This combination points to a disruption of normal autonomic regulation within the eye and, in susceptible individuals, can manifest as the triad described. While these ocular effects are uncommon, they are more aligned with this drug’s potential ocular side-effect profile than with the other anticonvulsants listed, which typically cause different eye findings (for example, diplopia or nystagmus) rather than the specific trio of mydriasis, elevated IOP, and cycloplegia.

So, recognizing this pattern helps identify phenobarbital as the anticonvulsant associated with that particular set of ocular adverse effects. If any patient on anticonvulsants develops sudden eye pain, visual changes, or redness, urgent ophthalmologic evaluation is warranted.