When managing children who are aphakic, who have congenital pathologies, or who have experienced ocular trauma, eyecare professionals often turn to custom soft contact lenses. While soft lenses can be effective for treating a variety of conditions, patients would benefit greatly in some cases from corneal GP contact lenses. Corneal GPs can also help mask surface irregularities, improve vision quality, and maximize visual prognosis during amblyopia management.

APHAKIA TREATMENT OPTIONS

The global prevalence of congenital cataracts is 1 to 15 in 10,000 children.¹ Genetics, Down syndrome, infections during birth such as rubella and chickenpox, and ocular trauma have been identified as potential causes for congenital cataracts.^2,3 Surgery is often recommended at between 4 and 6 weeks of age for unilateral cataracts and at 8 weeks for bilateral cataracts to minimize the risk of deprivation amblyopia, strabismus, and nystagmus;^4,5 however, intraocular lens (IOL) implantation in infants is not widely accepted.

The Infant Aphakia Treatment Study Group compared the safety and efficacy of IOLs with contact lens management and noted no significant difference in visual acuity outcomes between the groups.⁶ The researchers did note, however, that the eyes implanted with IOLs experienced more adverse effects compared with those wearing contact lenses.⁶

Because of their ease of fitting and management, silicone elastomer lenses have been the first line of treatment for children who have aphakia; however, these lenses have some limitations, as they are prone to surface deposits and have limited powers and parameters.⁷

Corneal GPs are also a good option for managing pediatric aphakia, as they offer power and parameter customization, high oxygen transmissibility, and low surface protein and bacteria adherence.^7,8 Aphakic children require long-term visual rehabilitation. With corneal GPs, there is a decreased risk of corneal compromise during prolonged wear.

OCULAR TRAUMA MANAGEMENT

Thirty-five percent of all ocular trauma cases occur in children, of which 20.9% are cases of a ruptured globe.⁹ Post-corneal-repair scarring can result in significant visual distortions and higher-order aberrations (HOAs) secondary to irregular astigmatism. There is widespread evidence that corneal GPs provide significant improvements in eyes that have nebular and nebulo-macular corneal scarring, and they provide slight improvements in glare acuity, contrast sensitivity, and mesopic vision.¹⁰

Studies have shown that patients who wear corneal GP lenses experience significant improvements in best-corrected visual acuity (P = 0.001)¹¹ and higher-order corneal aberrations (P = 0.008)^11,12 in comparison to wearing spectacles.¹³ Similarly, Titiyal et al noted an improvement of two or more lines of Snellen visual acuity when comparing corneal GPs to spectacles.¹⁴

Case Example: Post-Ocular Trauma A 6-year-old boy was evaluated for a contact lens for his right eye. He had a history of a globe rupture secondary to a full-thickness corneal laceration from a cardboard box at the age of two, for which he underwent corneal repair.

Slit lamp examination revealed an inferior corneal scar and dyscoria in the right eye, with a mild cataract located inferior and away from the visual axis; corneal topography revealed asymmetric astigmatism in the right eye, with flattening in the location of the inferior scar (Figure 1). Preliminary testing revealed uncorrected visual acuity of 20/400 in the right eye and 20/50 in the left eye. With a manifest refraction of –3.00 –3.50 x 140 in the right eye, the patient’s visual acuity improved to 20/80. The left eye had a manifest refraction of –1.50 –0.50 x 050 and visual acuity of 20/20.

Corneal GP lens fitting was initiated to evaluate visual potential. As the corneal astigmatism and spectacle astigmatism were similar and greater than 2.50D, the following bitoric corneal GP lens was ordered for the right eye: base curve radii of 42.00D/46.00D; overall diameter of 9.0mm; powers of –3.75D and –5.75D; optical zone diameter of 7.2mm; secondary curve radius of 8.50mm x 0.7mm; and peripheral curve radius of 12.00mm x 0.2mm.

At the dispensing visit, the patient’s visual acuity improved to 20/40 with the corneal GP lens. It was suspected that, because there was corneal irregularity that had remained uncorrected for a long time, there was a component of amblyopia. Patching of the left eye was initiated to improve visual prognosis in the right eye. This patient is being monitored frequently for amblyopia management.

STRATEGIES FOR PETERS ANOMALY

Peters anomaly is a congenital condition caused by incomplete separation of the anterior segment structures. During embryonic development, there is a delayed or incomplete separation of the lens vesicle that interferes with the corneal cell differentiation process; this results in central corneal opacities, anterior polar cataracts, and iridocorneal adhesions.¹⁵

The primary concern for patients who have Peters anomaly is the risk of amblyopia caused by form deprivation. Despite the guarded visual prognosis, surgical intervention and specialty contact lenses can work in tandem to improve visual prognosis and to aid visual development. These patients frequently require penetrating keratoplasty, cataract, and glaucoma surgeries.^16,17 Patients who have type 1 Peters anomaly with mild-to-moderate corneal opacity and no lens involvement have the potential for good visual function after penetrating keratoplasty.¹⁷ In such cases, large-diameter corneal GP lenses can improve visual quality by masking irregular astigmatism and by correcting HOAs. Amblyopia therapy should be initiated in conjunction with contact lens wear to improve visual development.

MANAGING MICROCORNEA

Microcornea, which can present unilaterally or bilaterally, is a congenital condition characterized by a corneal diameter that is less than 10mm.¹⁸ It commonly presents with ocular abnormalities such as cataracts, optic nerve hypoplasia, scleroderma, iris abnormalities, and glaucoma, all of which limit visual prognosis.¹⁸

In the case of cataracts, cataract surgery can help minimize the risk of amblyopia secondary to visual deprivation. Fifty percent of patients who have unilateral cataracts have the potential to develop visual acuity better than 20/200 with early intervention.¹⁹ While IOLs offer the advantage of vision correction,¹⁹ they are a controversial option for infants because of increased risks of lens subluxation, endothelial cell loss, and posterior capsular opacification in the growing eye.^20-22

Microcornea is often associated with flat corneal topographies and high refractive errors.^22,23 Contact lenses play an important role in visual rehabilitation of children who have unilateral aphakia, anisometropia, and high refractive errors.^22,23 Soft contact lenses (hydrogel and silicone hydrogel) are most commonly used to treat pediatric aphakia; however, corneal GPs have the added advantages of correcting irregular astigmatism and being fabricated in materials that provide excellent oxygen transmissibility. A number of hyper-permeable (Dk ≥ 100) lens materials can satisfy or approximate the Holden-Mertz criteria for oxygen transmissibility for daily and overnight lens wear, even with high plus powers.^24,25

VISUAL REHABILITATION OF IRREGULAR CORNEAS

In cases of corneal irregularities and trauma, children may present with irregular astigmatism that can negatively affect their visual prognosis. If left untreated, there can be significant amblyopia, strabismus, and nystagmus resulting from visual deprivation. In such cases, corneal GPs can mask the irregularity and help improve quality of vision. It is important to consider corneal GPs to aid visual rehabilitation in conjunction with amblyopia management to maximize visual potential for patients.

Corneal GPs promote excellent tear exchange that maximizes oxygen transmissibility,²⁵ offers low bacteria and protein adherence,²⁵ and corrects significant aberration from irregular astigmatism.^10-13,25 Some of the most important concerns related to corneal GPs in the pediatric population have pertained to contact lens compliance, tolerance, and complications.⁹ Studies have shown a high acceptance rate, minimal adverse effects, and good contact lens tolerance among young patients and their families.^13,26 Sufficient time devoted to patient and family education, application and removal training, and establishing a thorough disinfection protocol are key for a successful patient experience.²⁶

LONG-TERM MANAGEMENT

Pediatric patients require long-term management and frequent adjustments of lens parameters with age. Corneal GPs boast superior optics compared with traditional soft lenses, and they provide excellent tear exchange for these young patients, reducing the risk of corneal compromise. It is important to remember the role of corneal GPs—along with managing a patient’s amblyopia—for improved visual prognosis. Frequent follow-up visits and patching are required in conjunction with corneal GPs to maximize visual benefit and rehabilitation. CLS

REFERENCES

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