This article was originally published in a sponsored newsletter.
Springtime is a great season for children to engage in outdoor activities. With the increased outdoor exposure of grass and allergens, however, practitioners see a growing number of young patients who suffer from dry eye and ocular allergy concomitantly. Influence of screen time and digital work en masse has negatively impacted children’s blinking behavior, particular since the COVID-19 period.1,2
You may wonder, “How is dry eye and allergy related to childhood myopia?” While these two ocular conditions may appear to be unrelated, dry eye has been reported to be associated with the development of high myopia among Japanese teenagers.3 In this retrospective study, those who had high myopia also displayed a greater level of astigmatism and anisometropia compared to other cohort groups.
Although the exact pathogenesis and association between dry eye and myopia is yet to be definitive, objective reduction of tear breakup time and overexpression of matrix metalloproteinases-9 (MMP-9) have been found to be closely associated with the etiologies of many ocular surface disorders.4 More intriguingly, the genetic polymorphisms of the MMP genes in the family, notably the MMP-3 gene that governs breakdown of the matrix proteins in the sclera, have shown to increase the odds of developing myopia.5
Should this hypothesis hold true, targeting the sites of MMP-9 on scleral tissues could likely be a novel therapeutic intervention for myopia via controlled maneuvers of scleral expansion and, therefore, halting axial elongation of the globe. Practically, applying validated screening tools like Ocular Surface Disease Index6 and MMP tests can help clinicians ascertain the presence and severity of dry eye; this, in turn, can likely serve as a “precursor” or predisposing risk factors for myopia, particularly when patients are yet to be myopic or develop any observable symptoms of myopia.
To combat the onset of myopia, perhaps the more strategic way against myopia is to begin with other preventative measures to keep it at bay. Prevention of dry eye and ocular allergy might be the next frontier of keeping pre-myopes from developing myopia.
Unfortunately, the frequency of dry eye or ocular allergy has often been underdiagnosed or overlooked in children.7 A systemic review by Stapleton and colleagues reported that children suffering from dry eye often experience allergic conjunctivitis nearly as high as 23%.8
Unsurprisingly, pediatric patients with allergic symptoms are often tempted to rub their eyes to ease the itchiness and seemingly provide temporary relief. Nevertheless, it is commonly known that mechanical eye rubbing is closely associated with greater likelihood of developing atopy9 and keratoconus.10,11
Despite temporary symptom relief, eye rubbing can paradoxically exacerbate the symptoms since histamine and immunoglobin-E (IgE)-mediated responses are activated.12,13 Patients who were tested positive for IgE to indoor allergens had greater levels of myopia than those who had negative IgE findings.14 The cyclical conundrum has raised another question of whether the pathogenesis of myopia could somehow inherit other predisposing risk factors other than axial elongation alone.
The complexity of myopia development entails multidisciplinary approaches more than simply “treating myopia” alone. Practitioners need to be prudent with a holistic approach to address the concomitant ocular entities like dry eye and ocular allergy as preventative measures against myopia as well.
1. Elhusseiny AM, Eleiwa TK, Yacoub MS, et al. Relationship between screen time and dry eye symptoms in pediatric population during the COVID-19 pandemic. Ocul Surf. 2021 Oct;22:117-119.
2. Muntz A, Turnbull PR, Kim AD, et al. Extended screen time and dry eye in youth. Cont Lens Anterior Eye. 2022 Oct;45:101541.
3. Hirayama OI, Ayaki M, Yotsukura E, Torii H, Negishi K. Dry eye disease and high myopia in teenagers; a reciprocal relationship. Invest Ophthalmol Vis Sci. 2022 Jun;63:1442-F0400.
4. Jamerson EC, Elhusseiny AM, ElSheikh RH, et al. Role of Matrix Metalloproteinase 9 in Ocular Surface Disorders. Eye Contact Lens. 2020 Mar;46 Suppl 2:S57-S63.
5. Hall NF, Gale CR, Ye S, Martyn CN. Myopia and polymorphisms in genes for matrix metalloproteinases. Invest Ophthalmol Vis Sci. 2009 Jun;50:2632-2636.
6. Dougherty BE, Nichols JJ, Nichols KK. Rasch analysis of the Ocular Surface Disease Index (OSDI). Invest Ophthalmol Vis Sci. 2011 Nov 7;52:8630-8635.
7. Alves M, Dias AC, Rocha EM. Dry eye in childhood: Epidemiological and clinical aspects. Ocul Surf. 2008 Jan;6:44-51.
8. Stapleton F, Velez FG, Lau C, Wolffsohn JS. Dry eye disease in the young: A narrative review. Ocul Surf. 2024 Jan;31:11-20.
9. Yang K, Li D, Xu L, Pang C, Zhao D, Ren S. Independent and interactive effects of eye rubbing and atopy on keratoconus. Front Immunol. 2022 Sep 29;13:999435.
10. Ben-Eli H, Erdinest N, Solomon A. Pathogenesis and complications of chronic eye rubbing in ocular allergy. Curr Opin Allergy Clin Immunol. 2019 Oct;19:526-534.
11. Najmi H, Mobarki Y, Mania K, et al. The correlation between keratoconus and eye rubbing: A review. Int J Ophthalmol. 2019 Nov 18;12:1775-1781.
12. Shetty R, Sureka S, Kusumgar P, Sethu S, Sainani K. Allergen-specific exposure associated with high immunoglobulin e and eye rubbing predisposes to progression of keratoconus. Indian J Ophthalmol. 2017 May;65:399-402.
13. Ahuja P, Dadachanji Z, Shetty R, et al. Relevance of IgE, allergy and eye rubbing in the pathogenesis and management of Keratoconus. Indian J Ophthalmol. 2020 Oct;68:2067-2074.
14. Mimura T, Yamagami S, Usui T, et al. Relationship between myopia and allergen-specific serum IgE levels in patients with allergic conjunctivitis. Clin Exp Ophthalmol. 2009 Sep;37:670-677.
