I have a patient with polycythemia vera (PV) who wants laser-assisted in situ keratomileusis (LASIK) surgery. Are there any contraindications here?
“PV is a rare blood disorder in which there is an increase in all blood cells, particularly red blood cells,” says Justin Schweitzer, OD, who practices at Vance Thompson Vision in Sioux Falls, SD, and is an adjunct clinical professor at the Illinois College of Optometry. “Corneal laser vision correction (LASIK or photorefractive keratectomy [PRK]) in patients with PV has not been formally studied.”
What Causes PV?
While an exact cause of PV has yet to be discovered, evidence points to overactive signaling by proteins known as Janus kinases (JAKs).1 This results in the overproduction of blood cells in the bone marrow. It can also trigger overproduction of cytokine proteins, which in turn causes inflammation. An overabundance of cytokines has been linked to PV symptoms.
Researchers believe that overactive JAK signaling may be related to gene mutations, and almost everyone with PV has a mutation of the JAK 2 gene.1
|A subconjunctival hemorrhage, which can occur during LASIK, could be excessive in PV patients. Photo: Alan G. Kabat, OD, and Joseph W. Sowka, OD|
Where’s the Research?
A PubMed search using the key words “polycythemia vera,” “PV,” “LASIK” and “PRK” yields no results, and “there is nothing in the literature of absolute contraindications for a patient that has PV and wants to have corneal laser vision correction, but a few things need to be considered,” says Dr. Schweitzer.
The first consideration revolves around making sure the patient knows that research is lacking about the effect of refractive surgery on those with this blood disorder. “The informed consent for a patient with PV that elects to undergo corneal refractive surgery needs to state that PV has not formally been studied in corneal laser vision correction,” says Dr. Schweitzer. “PV can cause retinal complications, such as vitreous hemorrhages and thrombotic events, that are not linked to the corneal refractive procedure, and the patient needs to be made aware of those complications.”2
After having the conversation and ensuring the patient fully understands the risks, practitioners should document everything in the chart, Dr. Schweitzer suggests.
Think Through the Risks
Despite the lack of literature, clinicians must still consider the possible risks involved in the operation, and proceed accordingly. “In LASIK when the suction ring is applied for the procedure, subconjunctival hemorrhaging can occur,” says Dr. Schweitzer. “In a patient with PV, the subconjunctival hemorrhage could be excessive, and possibly difficult to stop.” Because of this, LASIK may not be the best refractive surgery option for these patients, Dr. Schweitzer believes. “If the patient ultimately decides they want corneal laser vision correction, PRK would be a better choice, as no suction ring is used for the procedure, limiting the risk of subconjunctival hemorrhaging.”
|1. Jakafi. About Polycythemia vera (PV). jakafi.com/polycythemia-vera.aspx. Accessed November 8, 2017. |
2. Kiratli H. Intraocular manifestations of proliferative hematopoietic disorders. In: Singh AD, Damato BE, Pe’er J, et al., eds. Clinical Ophthalmic Oncology. 1st ed. Philadelphia, PA: Elsevier Saunders; 2007:328-33.