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Ophthalmologists are well aware that pregnancy can induce physiologic and pathologic changes in the eye and can also affect pre-existing conditions. Some ocular changes may lead to permanent visual impairment.1 In women with pre-existing glaucoma, reports of both IOP increases and decreases have been published (with decreases in pressure much more common; see sidebar for more on glaucoma and pregnancy). Although rare, acute retinal necrosis can also occur in pregnancy. Other pathologic conditions such as uveal melanoma and central serous chorioretinopathy have been reported.
Myopic worsening has also been reported during pregnancy. Causes behind the refractive change have not been readily identified, but it does seem to be transient with myopic levels returning to near pre-pregnancy levels postpartum. A recent article found hormonal changes during pregnancy may adversely affect corneal biomechanics.2 The
authors noted pregnancy may therefore be a previously unrecognized risk factor for keratoconus progression in patients with no accompanying disease.
Pregnancy can also affect contact lens comfort, which may lead more pregnant women to investigate refractive surgery.
"Those kinds of hormonal changes can persist for a few weeks postpartum well into breastfeeding," said Sonia H. Yoo, M.D., professor of ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine. Among the transient refractive changes are increases in corneal thickness because of fluid retention during pregnancy and increases in corneal curvature as much as 1 D or more, Dr. Yoo said.
Taking refractions during pregnancy and/or breastfeeding can generate false data, said Y. Ralph Chu, M.D., Chu Vision Institute, Bloomington, Minn. For women who are breastfeeding, Dr. Chu suggests postponing any refractive surgery until after they've finished breastfeeding.
"Even though the risks are small, patients have to take eye drops after surgery, and we do not yet have good data on how—or if—that affects breast milk," he said. "I'm much more conservative and tell patients to wait."
For women who do not want to put off refractive surgery, Dr. Chu advises them to wait "at least 3 months" before trying to get pregnant.
"That's true for women who want laser vision correction or who need ICLs [implantable collamer lenses]," he said.
Dr. Yoo said that accommodation can also be affected by pregnancy, yet another reason to postpone any refraction work or surgery. During lactation, both accommodative insufficiency and paralysis have been reported, she added.
"There have even been reports in the literature about patients who discovered they were pregnant after they had already gone through refractive surgery. These women were followed for 6 months or more, and a significant percentage had regression," she said.
"Women should wait until they're finished breastfeeding," she said. "We want to treat a stable refraction, whether it's for ICLs, LASIK, or photorefractive keratectomy. Most refractive surgeons will advise against any kind of elective refractive surgery if a patient is currently pregnant or actively trying to get pregnant."
Dr. Chu added that because some of the refractive changes are metabolic in nature, healing can also be impacted.
"There's a slightly increased chance of scarring," he said.
Neither Dr. Yoo nor Dr. Chu alter the informed consent if the patient is postpartum, "but I do have to ask if she's pregnant or nursing," Dr. Yoo said. In some cases, she'll administer a pregnancy test. In general, however, the actual treatment is no more complicated.
"What can be tricky is the timing of the surgery," she said. "Most refractive changes seem to occur in the latter half of pregnancy, so I prefer to wait up to 6 months after she's given birth before scheduling surgery."
Further, there is no evidence that if a woman has had transient refractive changes in one pregnancy that it will recur in subsequent pregnancies. Nor is there any evidence to suggest refractive surgery (implant or laser vision correction) will prevent future transient changes in subsequent pregnancies.
"Post-surgery, we do use some medications, albeit eye drops with very minimal chances of causing an adverse systemic reaction," Dr. Yoo said. "But some of the steroid drops and cyclosporine A are in different classes in terms of risk for pregnant women."
All in all, refractive surgeons will best serve their patients by recommending delaying refractive surgery until well after breastfeeding is complete.
Editors' note: The doctors mentioned have no financial interests related to this article.
1. Barbazzetto IA, Pizzarello LD. Ocular changes during pregnancy. Compr Ophthalmol Update. 2007 May-June;8(3):155-67.
2. Bilgihan K, Hondur A, Sul S, Ozturk S.
Pregnancy-induced progression of
keratoconus. Cornea. 2011;30(9):991-4.
3. Razeghinejad MR, Tai TYT, Fundemberg SJ, Katz LJ. Pregnancy and glaucoma.
Surv Ophthalmol. 2011;56:324-335.
Chu: 952-835-1235, firstname.lastname@example.org
Yoo: 305-326-6322, email@example.com