Heterochromia Iridum: A PRISMA Guided Systematic Mini Review

Abstract Background: Heterochromia iridum is a rare presentation of the eye, which may be normal or a feature of congenital, neurological, ocular, and systemic disorders. Until now, there has been no documentation of its epidemiology in depth, especially in developing countries. Aim/Objective: The objective is to perform a literature review on the anatomical basis, prevalence, causes, clinical methods for its detection, and treatment options for heterochromia iridum that have been known within the Indian populace. Methods: The systematic review in this paper has been performed after following the principles of the PRISMA 2020 statement. A comprehensive search has been performed in PubMed, PubMed Central, Scopus, IndMED, MedIND, and major Indian ophthalmology journals for articles until December 2025. The inclusion criteria of this study included articles in English only, which are original articles, reviews, case series, and case reports. Results: Of the 112 retrievable records, 54 met inclusion criteria. Primarily, case reports were on benign congenital heterochromia, heterochromia with Horner syndrome, Waardenburg syndrome, and neurocutaneous syndromes. The literature could not be found that assessed the prevalence among the populations globally. There had been no Indian studies found on prevalence. Mostly case reports were found. Conclusion: Thus, the condition of heterochromia iridum itself is more of a diagnostic feature rather than a disease. Though most cases of heterochromia iridum are benign in nature, proper examination needs to be done in order to rule out other severe pathologies. The absence of data about the population in India is a major drawback for this review and should be highly considered in future studies. Keywords Heterochromia iridum; iris pigmentation; Horner syndrome; neural crest cells; PRISMA; India; epidemiology