Timing of Cataract Removal in Infancy May Affect Glaucoma Risk

By David Douglas

December 23, 2020

NEW YORK (Reuters Health) - A decade after undergoing cataract removal in infancy a substantial and increasing proportion of patients develop glaucoma or become glaucoma suspects, according to a secondary analysis of a randomized clinical trial.

As Dr. Sharon Freedman told Reuters Health by email, "Early removal of a cataract in the eye of an infant facilitates the development of vision in that eye. But the earlier the cataract is removed, the greater the risk that the operated eye will develop glaucoma."

For their study, published in JAMA Ophthalmology, Dr. Freedman of Duke University Medical Center, in Durham, North Carolina, and colleagues analyzed data from the Infant Aphakia Treatment Study (IATS), a multicenter, randomized, controlled clinical trial sponsored by the National Eye Institute.

One hundred and fourteen infants with congenital unilateral cataract were randomized to receive an intraocular lens (IOL), or to aphakia (contact lens, CL); 110 completed clinical examination at a mean age of 10.5 years. Mean follow-up after surgery was 10.4 years.

By the 10-year examination, 25 eyes (23%) had developed glaucoma, and 21 eyes (20%) were glaucoma suspects. There was no significant difference between groups. The CL group had 13 eyes (25%) with glaucoma and 13 (25%) were glaucoma suspects. In the IOL group, there were 12 eyes (22%) with glaucoma and eight (15%) were glaucoma suspects.

The risk of these diagnoses rose from 12% at one year after cataract removal, to 31% at five years and 40% at 10 years.

In keeping with results from other studies, younger patient age at surgery (28 to 48 days vs. 49 to 210 days) was a risk factor for the development of a glaucoma-related adverse event at one and five years.

And, say the researchers, "in multivariate analysis, it remains the strongest and only independent risk factor for glaucoma 10 years after surgery."

For development of any glaucoma-related adverse event at 10 years, "small corneal diameter at surgery, closely related to age at surgery emerged as the only risk factor," they add. As had been seen in previous follow-up, at 10 years "mean visual acuity was similar among eyes with glaucoma, glaucoma suspect, and neither diagnosis."

Thus, concluded Dr. Freedman, "This study confirms that a decade after surgery, earlier age at surgery remains a major risk for developing glaucoma and glaucoma suspect, and has implications for the ideal timing of unilateral cataract surgery in infancy."

Dr. Teresa C. Chen, a surgeon in the Glaucoma Service at Massachusetts Eye and Ear in Boston, told Reuters Health by email, "This paper is an important reminder that the incidence of glaucoma is common and increases over time after pediatric cataract surgery."

"Because vision loss from glaucoma is irreversible," added Dr. Chen, who was not involved in the study, "the key to preserving vision is early detection through life-long screening for glaucoma after pediatric cataract surgery."

Dr. Andrew Rabinowitz, chief medical officer at American Vision Partners in Phoenix, Arizona, said, "Infants who require cataract surgery for sight preservation have been known for decades to have an increased rate for the development of glaucoma suspicion and frank glaucoma."

"This study allows us to see that IOL placement does not raise the risk of development of glaucoma at 10 years when compared to leaving the patient aphakic," said Dr. Rabinowitz, who also was not involved in the research. "This is a critical observation as it mitigates any concern that IOL placement during infantile cataract surgery raises the risk of developing glaucoma at 10 years."

"It remains critical," he told Reuters Health by email, "that patients who undergo infantile cataract surgery must be watched on a lifelong basis beginning immediately following their surgery. This study shows that at 10 years, nearly half of the patients revealed elevated intraocular pressure regardless of whether they are pseudophakic or aphakic."

"Finally," concluded Dr. Rabinowitz, "the only discernible risk for the development of glaucoma or glaucoma suspicion following infantile cataract surgery is the age at which the cataract surgery is performed. The earlier in life that the cataract surgery is needed, the greater the chance that they will develop elevated intraocular pressure at 10 years and likely beyond."

SOURCE: https://bit.ly/2J8ZL6m JAMA Ophthalmology, online December 17, 2020.