Pediatric keratoconus presents unique challenges, often being more aggressive and difficult to diagnose compared to adult cases, leading to delays in treatment and potential vision loss.
At the recently held 5th World Congress of Pediatric Ophthalmology & Strabismus (WCPOS V 2024), experts emphasized the urgency of early detection and tailored treatments to manage this debilitating condition effectively.
Distinguishing pediatric from adult keratoconus
Firstly, Dr. Devina Annisa (Indonesia) discussed how pediatric keratoconus tends to progress more rapidly and severely than in adults, necessitating more frequent follow-ups and earlier intervention.
Key clinical indicators of developing keratoconus in children include: a higher average central corneal keratometry (vs periphery), increased posterior corneal elevation and thinner corneal thickness. “Keratoconus in children may manifest differently than in adults, where the cornea ectasia was located more centrally, and therefore irregular astigmatism is generally less pronounced in the early stage. As such visual acuity is not significantly affected and should not be used as an indicator for monitoring disease progression. And one should always be careful because pediatric keratoconus tends to show mild symptoms until the disease happens in both eyes,” she warned.
“The rapidity of progression in pediatric keratoconus suggests that it may be inappropriate to wait for signs of progression as we commonly do and observed in adults before offering treatment. Instead, treatment should be offered at diagnosis,” emphasized Dr. Annisa.
The impact of allergy and genetics
Genetics and allergy are two main causes of keratoconus in children, noted Dr. Dominique Brémond-Gignac (France). She highlighted that early diagnosis with recognition of progression through pediatric, genetic and allergic check-ups, and timely intervention with collagen cross-linking (CXL) are imperative to arrest the worsening of the disease.
Vernal keratoconjunctivitis (VKC) or atopic keratoconjunctivitis (AKC) are allergic conjunctivitis that often lead to significant itching, resulting in frequent eye rubbing which can worsen or accelerate the progression of keratoconus. Therefore, she advised clinicians to focus on reducing eye rubbing and to consider using steroid-sparing medications, such as cyclosporine A and tacrolimus ointment, for treatment.
“Early clinical diagnosis of VKC makes the difference in follow-up and prognosis. Adapted treatment improves quality of life and avoids iatrogenic vision threatening complications,” she explained.
Key considerations for CXL in pediatric keratoconus
Presenting on collagen cross-linking (CXL) in pediatric keratoconus, Dr. Rashmi Deshmukh (India) emphasized that CXL is the only method known to halt the progression of the disease. She noted that when performing CXL, it is important to consider associated risk factors, such as frequent eye rubbing, non-compliance and the presence of syndromes like Down syndrome and Leber congenital amaurosis (LCA). Rapid progression is very common in these cases, so addressing the ocular surface first is crucial.
“It’s better to perform early CXL rather than wait for the disease to progress. However, if the patient has active VKC, then the first thing to do is to treat it and rule out pseudo-progression. If a patient has VKC, you can anticipate early postoperative complications,” she said.
She also mentioned that epithelium-off CXL is more efficacious than transepithelial corneal CXL. And there might be patients who require repeat CXL, so patients need to be followed up postoperatively.
Meanwhile, Dr. Merle Fernandes (India) mentioned that even though complications following CXL in children are uncommon and similar to adults, it’s important to recognize them early in order to preserve vision. “It’s important to identify the risk factors and differentiate between sterile infiltrates and microbial keratitis. Early diagnosis and treatment avoids vision loss in this age group,” she said.
Special considerations for children with developmental delay
The primary goals in managing keratoconus are to diagnose it early, prevent the progression of ectasia and vision loss, rehabilitate vision, and avoid the need for corneal transplantation, highlighted Dr. Elizabeth Conner (New Zealand).
She identified trisomy 21 as one of the systemic conditions associated with keratoconus, which often manifests as high rates of refractive error and thin, steep corneas. Other conditions linked to keratoconus include trisomy 13, Ehlers-Danlos syndrome, Noonan syndrome, and osteogenesis imperfecta.
Diagnosing keratoconus in children, particularly those with developmental delays, can be challenging. As such, Dr. Conner stressed the importance of maintaining a high level of clinical suspicion, especially in the presence of allergic eye disease, worsening astigmatism, frequent eye rubbing and a family history of the disease.
When keratoconus is suspected, Dr. Conner recommended a step-wise approach: first, perform a clinical examination and attempt tomography; if unsuccessful, try optical coherence tomography pachymetry; and if that also fails, conduct an exam under anesthesia.
Regarding eye rubbing, it can cause mechanical stress, release inflammatory mediators and increase intraocular pressure. To prevent eye rubbing in children with developmental delays, she suggested managing allergies and inflammation, treating blepharitis, using bifocal glasses, addressing floppy eyelid syndrome and employing behavioral therapy.
Dr. Conner also highlighted the importance of managing postoperative pain in children with developmental delays. Strategies include using a sub-Tenon’s block, tarsorrhaphy or lid closure, oral analgesics or opiates, eye drops and sleeping tablets.
Topographic insights on CXL outcomes
Last but not least, Dr. Gerald W. Zaidman (USA) presented topographic findings in the eyes of children treated with CXL in order to halt or lessen keratoconus progression. Of a total of 62 eyes, 38 (61.3%) eyes were diagnosed with keratoconus and treated with CXL, 19 (30.6%) eyes were untreated and 5 (8.1%) were too severe for XCL and required corneal transplant surgery. Cross-linked and untreated eyes were compared on anterior mean keratometry (AKm), posterior mean keratometry (PKm), and thinnest pachymetry (TTP) using a two-tailed t-test.
Results showed that at initial presentation, treated eyes had a mean AKm of 48.6 D, PKm of -7.3 D, and TTP of 453.3 μm, whereas untreated eyes had means of 44.5 D, -6.6 D and 494.1 μm, respectively. The mean difference for AKm was 4.15 D, PKm was -0.744 D and TTP was -40.74 μm. Comparison of pre- and post-CXL topography demonstrated a statistically significant decrease in AKm (1.61 D, p=0.015, 95% CI±1.25 D).
“Children with keratoconus often present with more advanced disease and are at a greater risk of progression than adults. Earlier treatment with CXL may halt or slow progression of keratoconus. Our results indicate that pediatric keratoconus patients presenting with steeper AKm and PKm as well as thinner corneas should have CXL,” he concluded.
Editor’s Note: Reporting for this article occurred at the 5th World Congress of Paediatric Ophthalmology & Strabismus (WCPOS V 2024) from 11-13 July in Kuala Lumpur, Malaysia.
