Generally, medical therapy for childhood glaucoma has lower success rates and greater risks than medical therapy for adult glaucomas. However, it serves several important purposes in preoperative, postoperative, and long-term management, particularly in childhood glaucoma other than PCG. For example, medications can be used to lower IOP before surgery in order to reduce corneal edema and improve visualization during surgery. They may also be used after surgical procedures in order to provide additional IOP lowering.
Medical therapy for pediatric glaucoma also carries unique risks (Table 22-4) because of the greater dose per body weight and the limited number of controlled clinical trials in children. Although punctal occlusion may be used to reduce systemic absorption of topical medications, it may be impractical in many young children. Limiting the frequency of eyedrop administration in young children may enhance adherence.
Therapy with topical β-adrenergic antagonists, or β-blockers, may reduce IOP by 20%–30%. The major risks of this therapy are respiratory distress (caused by apnea or bronchospasm) and bradycardia, both of which occur mostly in small infants and in children with a history of bronchospasm. Betaxolol, a cardioselective β1-adrenergic antagonist, may be safer than a nonselective β-blocker for use in patients with asthma, but its pressure-lowering effect is less than that of nonselective agents.
Table 22-4 Systemic and Ocular Adverse Effects of Glaucoma Medications in Children
Topical carbonic anhydrase inhibitors (CAIs) are effective in children, but they produce a smaller reduction in IOP (<15%) than do β-blockers. Corneal edema is a risk of topical CAIs; thus, they should be used with caution in children with coexisting corneal disease.
Prostaglandin analogues are effective in many pediatric patients. Their low systemic risk and once-daily dosing are advantageous.
Miotics are rarely used in children; perioperative pilocarpine, however, may facilitate angle surgery. Pilocarpine and echothiophate may be effective in patients with aphakic glaucoma.
The α2-adrenergic agonist apraclonidine may be useful for short-term IOP reduction, but there is a high incidence of tachyphylaxis and allergy with use of this drug in young children. Brimonidine, another α2-adrenergic agonist, effectively reduces IOP in some cases of pediatric glaucoma. Both medications can produce somnolence and respiratory depression in infants and young children. Infants and young children are particularly susceptible to brimonidine’s adverse effects. Therefore, brimonidine should be used with caution in children younger than 6 years, and it is relatively contraindicated in children younger than 2 years because of the risk of respiratory depression. There are similar limitations for the use of fixed-dose combination drugs such as brimonidine/timolol and brinzolamide/brimonidine in the pediatric population.
Oral CAIs may be used effectively in children, particularly to delay the need for surgery or to clear the cornea before goniotomy. Their usefulness may be limited because of their systemic adverse effects (see Table 22-4).
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.