Understanding children's eyewear needs

Consultants are famous for pithy sayings that point to some characteristic of the world in which we work. One of the sayings I've come to use often is, "Pediatrics is different."

There are quite a few ways in which pediatric ophthalmology practices are different from other subspecialties and comprehensive ophthalmology practices. For example, pediatric ophthalmologists earn less money than their ophthalmology colleagues. This causes lots of problems when group practices undertake capital projects and allocate expenses.

Even the pediatric ophthalmology examination is different. Children are not always good communicators or able to describe what they are seeing.

In addition, children tend to have a short attention span and therefore must be kept engaged. Pediatric ophthalmologists are famous for keeping an array of toys and colorful objects for children to focus on and maintain their attention. The short attention span also requires pediatric ophthalmologists to make assessments quickly. There is very little time to get a child to respond to a stimulus or question.

Many of the children seen in pediatric ophthalmology practices are not familiar with the letters of the alphabet. Consequently, pediatric ophthalmologists use visual acuity slides that display familiar objects or even an entire chart made of only Es with the letters' legs pointing in various directions.

Fitting children with eyeglasses

Pediatrics is different in other ways, too. "Children are not mini versions of adults. Their eyes, brains, and bodies still are developing," said Tracy Crnic, MD, a pediatric ophthalmologist who practices in Amarillo, TX.

An optician, therefore, cannot dispense to children the way he or she dispenses to adults. Following are some aspects of pediatric dispensing an optician should consider.

• Most lenses are plus. "Because children are born naturally hyperopic, most eyeglasses for small children have plus lenses," Dr. Crnic said. When fabricating the glasses, it is important to have the lenses custom-ground in an optical laboratory. This way, the edge status of the lens can be controlled. This is not possible when using most stock lenses.

• Many prescriptions are complex. Many prescriptions written for children are strong. Strong lenses need to be oriented properly in front of the eye (vertex distance) in order for them to be effective. As the power of the lens increases, even small changes in the vertex distance will cause the lens to have a different effective power from what was prescribed. Vertex distance measurements need to be taken and the prescription compensated for all prescriptions above ±4 D.

It is not unusual for children's eyeglasses to have high cylinders with an against-the-rule axis or one that is oblique. This will require the face form tilt and pantoscopic tilt to be accurate or the cylinder axis will shift and the power will be affected.

• Use impact-resistant lenses. "Because children are extremely active, only polycarbonate or Trivex lenses should be used," Dr. Crnic said. "This will protect a child's eyes as he or she engages in an active lifestyle."

• Fitting bifocals. A number of children's eye disorders could benefit from the use of bifocals. Most of these disorders have to do with strabismus or focusing issues. Fitting a child with bifocals, however, is different from fitting an adult with bifocals. For children, the bifocals' second line needs to be placed so that it splits the pupil.

• Refit children often. Children grow quickly, which means a frame that fits today will not fit in a short time. As a rule of thumb, Dr. Crnic recommended that the fit of a child's frame be re-evaluated every time his or her shoe size changes.