PAEDIATRIC REFRACTIVE SURGERY

Refractive surgery for treatment of severe myopia, hyperopia, and astigmatism in children who are non-responsive with standard therapy is safe, effectively reduces refractive error, and improves vision and stereopsis along with quality of life. Therefore, it is a reasonable choice for children with severe refractive error, if not the treatment of choice in some patients, said Evelyn A. Paysse, MD, speaking at a joint session of the 3rd World Congress of Paediatric Ophthalmology and Strabismus in Barcelona, Spain.

The diagnoses for considering paediatric refractive surgery include severe anisometropia or severe isoametropia in a child with amblyopia that has failed standard therapy. In addition, it has value in children with facial anatomic anomalies and other special needs that preclude use of glasses or contact lenses.

“There are many reasons why children can fail amblyopia therapy or be unable to have success with spectacle or contact lens wear. With no other options for treating refractive error in these children in the past, the result was permanent severe visual impairment in one or both eyes,” said Dr. Paysse, Baylor College of Medicine, Houston, TX, USA.  

“Now we have refractive surgery with the excimer laser or with phakic IOLs or refractive lens exchange for ultra-high refractive error.”

REFRACTIVE ERROR THRESHOLDS
Dr. Paysse outlined refractive error thresholds for considering paediatric refractive surgery. Her suggested entry levels were severe anisometropia ≥4.0D or severe isoametropia with bilateral myopia ≥-6.0D, bilateral hyperopia ≥+4.0D, or bilateral astigmatism >3.0D.

“I find that I rarely use these criteria, however, because most of my patients have much higher levels of refractive error,” she said.

Outcomes of paediatric excimer laser surgery for severe anisometropia were analysed in a recent meta-analysis that included data from about 800 children who were ages 2 to 16 years old at the time of intervention. The benefits included reduction of refractive error from a mean -18.0D to about -3.0D among myopes and from about +9.0D to about +1.0D for hyperopes. Visual acuity improvement averaged about 3 lines in both subgroups and ranged up to 7 lines. In addition, about half of the children benefitted with stereopsis improvement.

Dr. Paysse said she has achieved similar refractive results in her personal experience with excimer laser surgery to treat high myopia, hyperopia, and astigmatism, which encompasses about 100 cases performed since 2001. Refractive error analysis showed slight undercorrection at 1 year that remained stable at 3 years of follow-up.  

BEHAVIOURAL CHANGES
Dr. Paysse told attendees that the behavioral changes she witnessed in a child treated 12 years ago with refractive surgery enlightened her about the broader potential value of having normal refractive error and good vision. The child in this “epiphany case” was affected by a chromosomal translocation. She was a -13.0D myope, wheelchair-bound, and combative. She was frightened by anyone who came near to her, would avoid eye contact, and had never stood on her own. 

“With -13.0D of uncorrected myopia, everything is out of focus unless it is at a very close distance of about 2 inches from the face. But then, there is a loss of peripheral vision,” said Dr. Paysse.

“For children who already have cognitive issues, their high refractive error is handicapping them further.”

Dr. Paysse reported that at her 3-month follow-up visit, the child’s refractive error was -0.75D OU, and she was walking with a walker. At 6 months, she came in walking unassisted and had become a smiling, social, and happy child.

“She became interested in things, hugs me when she sees me, and after 12 years, her refractive error is -0.75D OU,” Dr. Paysse said.

Feeling that normalisation of this child’s refractive error had an impact beyond just vision improvement, Dr. Paysse sought to substantiate her impression with objective data. Therefore, she conducted a study to analyse developmental changes after PRK in children with isoametropic amblyopia and behavioral disorders.

The primary outcome was change from baseline to 6 months in the development quotient (DQ)[calculated as mental age (mos) x100/biological age (mos)] for communication, daily living skills, socialization, and motor and adaptive subdomains. The analyses showed improvements in all subdomains’ DQs, and the changes were statistically significant for three communication subdomains (receptive, expressive, and written), the domestic subdomain of daily living skills, and the interpersonal subdomain for socialization.

“The DQ in neurochallenged children can be higher when they are 2 years of age than at 8 years of age when their mental age has plateaued out. Any stabilization in DQ is pretty much unheard of in this population, and yet we saw statistically significant improvements after 6 months,” said Dr Paysse.

“The subdomain DQs plateaued after 12 months without any statistically significant change during follow-up to 36 months. Those results are still truly remarkable clinically, however, due to the severe intellectual disability present in all of the subjects.”
ENDS

Evelyn A Paysse MD:
eapaysse@texaschildrens.org