Abstract
Purpose :
Distinguishing iris melanomas from iris nevi can be challenging as few clinical features other than documented growth are helpful in making the diagnosis. Classic textbook criteria for differentiating benign versus malignant iris tumors are limited and may result in overtreatment. Previous reports show iris melanomas are associated with elevated intraocular pressure (IOP) and secondary glaucoma. In our experience, intrasubject optic nerve and IOP asymmetries have been noted in iris melanoma, even without a pre-existing diagnosis of glaucoma. In this study, we compared the cup-to-disc ratio (CDR) and IOP between eyes of subjects with iris melanomas and used subjects with iris nevi as controls.
Methods :
This was a single-institution retrospective study for patients treated for iris melanoma and iris nevi from January 2013 and October 2022. All subjects identified with iris melanomas were included in this study. Patients with unilateral iris nevi were included if they had two evaluations at least two years apart with no malignant transformation. The electronic health record was reviewed for patient characteristics. A Student’s T-test was used to compare differences between eyes and subject populations.
Results :
In total, 39 subjects with iris melanomas and 40 age-matched subjects with iris nevi were included. The average IOP for eyes with iris melanomas and the contralateral eyes were 18.8±6.1 mmHg and 16.3±3.5 mmHg (P=0.03), respectively. The average IOP for eyes with iris nevi and the contralateral eyes were 14.6±3.5 mmHg and 14.5±3.2 mmHg (P=0.89), respectively. The difference in IOP between eyes for subjects with iris melanoma was significantly greater than the difference for subjects with iris nevi (P=0.03). Similarly, the average difference in the recorded CDR between eyes for subjects with iris melanomas was 0.11±0.21 units, which was significantly greater than the difference for subjects with iris nevi of 0.02±0.11 units (P=0.03).
Conclusions :
We demonstrate patients with iris melanomas are more likely to have greater IOP and CDR in the affected eye compared to the unaffected eye. When compared to the control iris nevi group, the asymmetry in IOP and CDR is also greater for subjects with iris melanomas. Therefore, IOP and CDR asymmetries may add to a clinical evaluation to raise suspicion for the diagnosis of iris melanoma, while lesions without these asymmetries and growth may warrant observation alone.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.