Enantiomorphic Glaucoma Displayed in Monozygotic Twins

Authors

  • Kimberly M. Dillivan

DOI:

https://doi.org/10.65636/cjo.v75i3.7300

Keywords:

Primary open-angle glaucoma, monozygotic twins, generics, Humphrey Visual Fields, nerve fiber layer defect

Abstract

Background: Numerous theories exist about the etiology of glaucoma and various forms of research, including twin studies, are conducted to provide answers. Twin studies are an exceptional method of examining the genetic and environmental influences on primary open-angle glaucoma (POAG) since comparison of monozygotic and dizygotic twins can infer a genetic causative factor.

Case Report: A pair of monozygotic twins revealed strikingly similar examination results with the eventual diagnosis of POAG. Visual fields and fundus photography revealed enantiomorphic, or mirror image, likeness. The right eye of twin one (T1) and the left eye of twin two (T2) displayed a repeatable inferior arcuate defect and retinal nerve fiber layer defects (RNFL).

Conclusion: An obvious genetic link within POAG is demonstrated by these twins. A dual case presentation will be described and a conclusion of the genetic backbone of glaucoma will be presented with supporting research. These studies provide information on genes responsible for POAG, environmental factors inducing POAG, and more insight for clinicians and patients so that better treatments may evolve in the future.

References

1. Hewitt AW, Craig JE, Mackey DA. Complex genetics of complex traits: the case of primary open-angle glaucoma. Clin Experiment Ophthalmol 2006;34: 472-484. DOI: https://doi.org/10.1111/j.1442-9071.2006.01268.x

2. Quigley HA, Broman AT. The number of people with glaucoma worldwide in 2010 and 2020. Br J Ophthalmol/ 2006,90:262. DOI: https://doi.org/10.1136/bjo.2005.081224

3. Okeke CN, Friedman DS, Jampel HD, er al. Targeting relatives of patients with primary open angle glaucoma: The help the family glaucoma project. ] Glaucoma. 2007;16(6):549-55. DOI: https://doi.org/10.1097/IJG.0b013e3180391a4c

4. Vajaranant TS, Wu S, Torres M, Varma R. The changing face of primary open-angle glaucoma in the united states: Demographic and geographic changes from 2011 to 2050. Am J of Ophthalmol 2012:1-12. DOI: https://doi.org/10.1016/j.ajo.2012.02.024

5. Mysteries of glaucoma revealed in landmark CNIB-funded study. www.cnib.ca/en/research/news/Pages/glaucoma-study-0807.aspx. Accessed July 2012.

6. Mackey DA. Gillies lecture: dissecting glaucoma: understanding the molecular risk factors. Clin Experiment Ophthalmol 2008,36:403-09. DOI: https://doi.org/10.1111/j.1442-9071.2008.001798.x

7. Healey P, Carbonaro F, Taylor B, Spector TD, Mitchell P, Hammond CI. The heritability of optic disc parameters: a classic twin study. lest Ophthalmol Vis Si 2008;49(1):77-80. DOI: https://doi.org/10.1167/iovs.07-0962

8. Lee BI, Bathija R, Weinreb RN. The definition of glaucoma. ] of Glane 1998;7:366-71. DOI: https://doi.org/10.1097/00061198-199812000-00003

9. Tomita G, The optic nerve head in normal tension glaucoma. Current Opinion in Ophth 2000,11(2):116-120. DOI: https://doi.org/10.1097/00055735-200004000-00009

10. Park HY, Jurg KI, Na KS, et al. Normal-tension glaucoma patients with autonomic dysfunction and abnormal peripheral microcirculation. Am J of Ophth 2012154(3):466-75. DOI: https://doi.org/10.1016/j.ajo.2012.03.028

11. Iester M, Deleo F, Gordon DR. I. Visual field loss morphology in high- and normal-tension glaucoma. J of Op 2012;2002:1-8. DOI: https://doi.org/10.1155/2012/327326

12. Kamal D, Hitchings R. Normal tension glaucoma. Br] of Oph 1998,82.835-840. DOI: https://doi.org/10.1136/bjo.82.7.835

13. Hewitt AW, Poulsen JP, Alward WLM, et al. Heritable features of the optic disc: a novel twin method for determining genetic significance. Invest Ophthalmol Sci 2007;48(6):2469-75. DOI: https://doi.org/10.1167/iovs.06-1470

14. Tahat AA, AI-Khawaldeh AM. Hypothyroidism and open-angle glaucoma: an accidental or an essential coexistence? East Med Health ] 2000,6:299-303. DOI: https://doi.org/10.26719/2000.6.2-3.299

15. McDaniel D, Besada E. Hypothyroidism: a possible etiology of open-angle glaucoma. J Am Opt Assoc 1996;67(2):109-14.

16. Toh T, Liew SHM, MacKinnon JR, et al. Central corneal thickness is highly heritable: the twin eye studies. Invest Ophthalmol Vis Sci 2005;46(10):3718-22. DOI: https://doi.org/10.1167/iovs.04-1497

17. Gottfredsdottir MS, Sverrisson T, Masch DC, Stefansson E. Chronic open-angle glaucoma and associated ophthalmic findings in monozygotic twins and their spouses in Iceland. J Glaucoma 1999,8:134-39. DOI: https://doi.org/10.1097/00061198-199904000-00009

18. Teikari JM. Genetic factors in open-angle (simple and capsular) glaucoma. Ophthalmologica 1987,65:715-20. DOI: https://doi.org/10.1111/j.1755-3768.1987.tb07069.x

19. Klein BE, Klein R, Lee KE. Heritability of risk factors for primary open-angle glaucoma: The beaver dam eye study. IOS. 200445(1):59-62. DOI: https://doi.org/10.1167/iovs.03-0516

20. Vegini E, Figueiroa- Filho N, Lenci RE; Garcia-Neto D, Susanna-Junior R. Prevalence of open angle glaucoma in accompanying first degree relatives of patients with glaucoma. Clinics 2008;63:329-32. DOI: https://doi.org/10.1590/S1807-59322008000300007

21. Wiggs JI. Genetic etiologies of glaucoma. Ophthalmolgica. 2008;125:30-7, DOI: https://doi.org/10.1001/archopht.125.1.30

22. Fried K, Sachs R, Krakowsky D. Congenital glaucoma in only one of identical twins. Ophthalmologica 1977,174185-87.

23. Gerta L, Scullica L, Accardi A. Concordant glaucoma in mz twins. Acta Geneticae Medicae et Gemellologiae 1970;19(13:268. DOI: https://doi.org/10.1017/S112096230002566X

24. Ofner S, Samples JR. Low-tension glaucoma in identical twins. Am] Ophthalmol 1992;114(6):764-5. DOI: https://doi.org/10.1016/S0002-9394(14)74057-7

25. Potts CR. Hydrophthalmia in identical twins. Trans Am Ophthalmol Soc. 1950;48:751-52.

26. Rasmussen DH, Ellis PP. Congenital glaucoma in identical twins. Arch Ophthal 197084.827-30. DOI: https://doi.org/10.1001/archopht.1970.00990040829024

27. AIlingham RR, Lui Y, Rhee DI The genetics of primary open-angle glaucoma: A review Esp Eye Research., 2009,88:837-44. DOI: https://doi.org/10.1016/j.exer.2008.11.003

28. Kwon YH, Fingret JH, Kuehn MH, Alward WLM. Mechanisms of disease: Primary open-angle glaucoma. NEngl] Med 2009;360:1113-24. DOI: https://doi.org/10.1056/NEJMra0804630

29. Kramer PL, Samples JR, Monemi S, et al. The role of the WDR36 gene on chromosome 5422.1 in a large family with primary open-angle glaucoma mapped to this region. Arch Ophthalmol 2006;124:1328-31. DOI: https://doi.org/10.1001/archopht.124.9.1328

30. Craig JE, Baird PN, Healey DL, et al. Evidence for genetic heterogeneity within eight glaucoma families, with the GLC1A GIn368STOP mutation being an important phenotypic modifier. Ophthalmology 2001 ;108(9):1607-20. DOI: https://doi.org/10.1016/S0161-6420(01)00654-6

Published

2026-08-26

How to Cite

Dillivan, K. M. (2026). Enantiomorphic Glaucoma Displayed in Monozygotic Twins. Canadian Journal of Optometry, 75(3), 53–64. https://doi.org/10.65636/cjo.v75i3.7300

Issue

Section

Case Reports and Series