At A Glance
- Although optometrists’ understanding of and instruction on the fitting of specialty contact lenses continues to advance, the fitting process is not easy.
- Specialty contact lens fitting gives optometrists an opportunity to specialize their practices, cultivate new skills, and—most important—help patients.
- Using advanced technology may improve the efficiency of a contact lens fitting and enhance clinical outcomes.
The field of specialty contact lens fitting is booming. Although this practice began several decades ago, it was only recently that technological improvements made the fitting of specialty contact lenses accessible to a greater number of optometry offices. With advanced training and cutting-edge technology, optometrists are in a better position than ever to enhance patients’ vision, comfort, health, and quality of life. This article describes how to meet the challenges of specialty contact lens fitting in children.
A COMPLEX PROCESS
Despite advances in optometrists’ understanding of and instruction on the fitting of specialty contact lenses, the fitting process is not easy. It takes a great deal of time, energy, and discipline to acquire and cultivate the skills required to become a successful practitioner of specialty contact lenses. Moreover, what the phrase specialty contact lenses encompasses is subjective. In general, most optometrists use this expression to refer to rigid gas permeable (RGP) lenses, scleral lenses, orthokeratology lenses, hybrid lenses, and a variety of customized soft lenses (cosmetic, aphakic, etc.).
The complexity of the specialty contact lens fitting process depends on a wide variety of factors such as the underlying reason for the fitting (a patient’s ocular and/or systemic conditions), available technologies (corneal and/or scleral topography, endothelial cell count, etc.), and dexterity (ability to insert and remove lenses). A patient’s age can also contribute to the difficulty and success of a specialty contact lens case, as the cases presented in this article show.
CASE NO. 1
A 4-year-old white male was referred to the specialty contact lens clinic for a consultation. The patient had a history of globe rupture in the right eye from a high-velocity wooden projectile. He had undergone surgery to remove a traumatic cataract. Additionally, a scleral buckle had been placed to repair a scleral laceration and prevent a future retinal detachment. Areas of chorioretinal atrophy were present peripherally without damage to the retina, macula, or optic nerve head. The injury had resulted in an aphakic eye with a scleral buckle in place and a visually significant corneoscleral laceration extending horizontally limbus to limbus 1 to 2 mm below the visual axis.
Other findings (IOPs, pupils, extraocular muscles, etc.) from the preliminary examination were within normal limits. Visual acuity testing was attempted, but an accurate measurement could not be obtained because of poor patient cooperation. For this reason, an in-office specialty contact lens fitting was not possible, and an examination under anesthesia (EUA) was imperative for a fitting to proceed. The patient’s parents agreed to have the patient undergo an EUA for a specialty contact lens fitting. A standard soft contact lens would likely have been ineffective because of the irregular astigmatism caused by corneal scarring.1-3
During the EUA, an impression mold was taken of the patient’s right eye using EyePrintPRO (EPP) technology (EyePrint Prosthetics). An EPP lens fitting entails applying an impression material to the ocular surface, keeping the material in place until it stabilizes, and then removing it. The process is similar to when an orthodontist takes a dental mold for a retainer. After removal of the impression, an aphakic RGP trial lens set was used to perform an overrefraction to determine the lens prescription. The EPP impression was then sent to the laboratory, where it was digitized with proprietary software to construct an RGP lens that was optimally fit to the ocular surface that it was designed to cover (ie, this patient’s right eye). The final parameters included a base curve of 9.55 mm, an overall diameter of 11.0 mm (the patient had a large cornea for his age), and a power of +24.62 D sphere (Figure 1).
Figure 1. A digitized impression created with EPP technology. The best-fit EyePrint RGP lens is highlighted in green.
The patient’s parents were both trained on appropriate RGP lens care and maintenance and given instructions on the proper application and removal of an RGP lens. The cleaning and storage of RGP lenses is typically the same for children and adults. The parents place the lens on the patient’s right eye before he wakes up and remove it after he is asleep. Wear time began with a couple of hours and has increased steadily over time.
The patient has been successfully wearing a customized EPP-designed RGP lens for 2 months. Patient cooperation during examinations continues to be a challenge, and an accurate measurement of visual acuity remains elusive. The patient’s parents, however, have reported a functional improvement in his daily activities and no noticeable level of discomfort. The patient will be monitored closely, and lens refitting will be frequently indicated as his eye grows and changes. See Strategies for Success for helpful pointers on fitting young patients.
STRATEGIES FOR SUCCESS
Employ technology. Using advanced technology may improve the efficiency of a contact lens fitting and enhance clinical outcomes. In Case No. 1, using an EyePrintPRO–designed impression allowed the creation of a unique RGP lens that was tailor-made for the patient’s eye. This level of customization generally reduces the number of remakes and augments overall patient and practitioner satisfaction. It was particularly useful in this case because the patient required an examination under anesthesia.
Enlist parents’ or caregivers’ support. Fitting a young child in a specialty contact lens is pointless if the parents or caregivers are unwilling to participate in the application, removal, care, and maintenance of the lens. They must be properly trained and demonstrate proficiency in these areas for a young patient to wear the lens successfully.
Alleviate the concerns of parents or caregivers. Based on the age and maturity of the child, he or she may resist the placement of a lens. It is important for parents to understand that the lens is not hurting the child and that the benefits (eg, a reduced risk of amblyopia4) far outweigh the risks. Additionally, RGP lens wear is a safe method for optical correction in children.5
Use a team approach. When managing patients with a complex ocular disease, it is important to recognize that many of them have accompanying complications that require management by other eye care professionals. In this case, the patient was under the care of a pediatric cataract surgeon, a pediatric retinologist, and a specialty contact lens practitioner, all working as a team to maximize outcomes.
CASE NO. 2
A 12-year-old white male was referred by the pediatric ophthalmology clinic for a specialty contact lens evaluation. The patient’s ocular history was significant for bilateral degenerative myopia, bilateral refractive amblyopia, and a mild variety of bilateral cone-rod dystrophy (Figure 2). He reported symptoms of minification while wearing corrective spectacle lenses and expressed a desire to engage in sporting activities at school.
Figure 2. Retinal images (Optos) of the right (top) and left (bottom) eyes. Pigmented lattice degeneration is evident in the far temporal periphery in the right eye. Benign whitewithout pressure is present in the periphery of each eye.
Best corrected distance visual acuity was 20/125 with a manifest refraction of -17.00 -2.25 x 015º OD and 20/40 with a manifest refraction of -16.00 -1.75 x 180º OS.
Corneal topography was performed to aid the contact lens fitting (Figure 3). Despite the patient’s regular astigmatism, RGP lenses were selected because they often provide the best subjective vision to patients.3 The topographic images were then used in tandem with a diagnostic fitting set to find a best-fit lens. Because the corneal astigmatism was regular, the patient was fit with spherical RGP lenses. He was ecstatic with his visual outcome: Best corrected distance visual acuity was 20/70 OD and 20/30 OS. The final RGP lens parameters are shown in the Table.
Figure 3. Corneal topography via Scheimpflug photography of the right (top) and left (bottom) eyes. This information was used to assess corneal astigmatism, which allowed selection of a diagnostic fitting lens and necessary adjustments to design the final RGP lens.
The patient was mature enough to become proficient at applying and removing his RGP lenses, and he was instructed on their appropriate care and maintenance. He has been happily wearing the lenses for 6 months, and he has been playing both soccer and baseball while wearing his RGP lenses. Read Pro Tips for some additional tricks of the trade.
- Ensure an accurate refraction. Consider placing a contact lens with a high minus power on the eye before performing a refraction with loose lenses or a phoropter. This strategy may reduce the visual distortion that can occur with higher phoropter or loose lens powers. Furthermore, the upper limit of phoropter minus lens powers is approximately -20.00 DS. Refraction with a contact lens that has a high minus lens power on an eye with a refractive error that is greater than -20.00 DS can lead to a more accurate prescription. Don’t forget to make sure the contact lens and spectacle powers are vertexed when calculating final power.
- Consider your fitting strategy. Debate continues over whether an RGP fitting is better conducted empirically or with a diagnostic fitting set. The use of trial lenses provides immediate data and information for the contact lens specialist, but it requires more chair time. Empirically designing lenses may save time, but a consultant is often required to design a lens on your behalf. We are of the opinion that, as technology progresses, we will be able to fit more eyes empirically with diagnostic imaging, but there currently is no substitute for using a trial lens set on highly complex or irregular corneas.
- Encourage an active but safe lifestyle. Some specialty contact lens practitioners discourage patients from wearing RGP lenses during sporting activities. One reason is that, because RGP lenses tend to be small and often demonstrate appreciable movement, they are more likely than other lenses to be displaced from the eye. Although there is some validity to this concern, in our experience patients with active lifestyles can wear RGP lenses successfully. Some precautions include having a backup pair of RGP lenses and always having an updated pair of spectacles on hand.
WORTH THE EFFORT
At times, fitting specialty contact lenses in children can be a frustrating and stressful process, but the experience is truly rewarding more often than not. It will give you an opportunity to specialize your practice, cultivate new skills, and—most important—help patients. Moreover, favorable outcomes are likely to win you lifelong patients. As technology advances, results will continue to improve.
- 1. de Jong B, van der Meulen IJE, van Viet JMJ, Lapid-Gortzak R, Nieuwendaal CP, van der Berg TJTP. Effects of corneal scars and their treatment with rigid contact lenses on quality of vision. Eye Contact Lens. 2018;44(suppl 1):S216-S220.
- 2. Aung YY, McLeod A. Contact lens management of irregular corneas after traumatic aphakia: a pediatric case series. Contact Lens Anterior Eye. 2015;38(5):382-388.
- 3. Michaud L, Bennett ES, Woo SL, et al. Clinical evaluation of large diameter rigid-gas permeable versus soft toric contact lenses for the correction of refractive astigmatism. A multicenter study. Eye Contact Lens. 2018;44(3):164-169.
- 4. Mohammadpour M, Shaabani A, Sahraian A, et al. Updates on managements of pediatric cataract. J Curr Ophthalmol. 2018;31(2):118-126.
- 5. Chen J, Sun P, Wei Y, Kang X. Evaluation of eye-related parameters and adverse events of rigid gas permeable contact lens and spectacles correction in infants with monocular aphakia after congenital cataract surgery: a retrospective clinical study. BMC Ophthalmol. 2019;19(1):81.