Eyeworld

MAR 2012

EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.

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100 100 EW REFRACTIVE March 2012 Pregnancy and refractive surgery by Michelle Dalton EyeWorld Contributing Editor Hormonal changes have the potential to adversely affect outcomes pregnancy levels postpartum. A re- cent article found hormonal changes during pregnancy may adversely af- fect corneal biomechanics.2 The authors noted pregnancy may there- fore be a previously unrecognized risk factor for keratoconus progres- sion in patients with no accompany- ing disease. Pregnancy can also affect con- tact 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 be- cause of fluid retention during preg- nancy and increases in corneal curvature as much as 1 D or more, Dr. Yoo said. Taking refractions during preg- nancy and/or breastfeeding can gen- erate false data, said Y. Ralph Chu, M.D., Chu Vision Institute, Bloom- ington, Minn. For women who are breastfeeding, Dr. Chu suggests post- poning 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 preg- nant. "That's true for women who want laser vision correction or who need ICLs [implantable collamer lenses]," he said. continued on page 102 Pregnancy and glaucoma A newly published overview on how glaucoma may affect women of child-bearing age notes the disease presents a particular manage- ment challenge in this group of patients.3 of the findings: In healthy eyes, pregnancy has been associated with about a 10% drop in IOP, with the largest decrease in the second trimester. In women with ocular hypertension, the largest IOP decrease occurred in the third trimester. However, many women will continue to require glaucoma medications throughout their pregnancy, and the disease may progress during pregnancy, with one study finding 36% of the 28 eyes (15 pregnant women) had either disease progression or progressive visual field (VF) loss. Edema is thought to cause transient corneal thickness increases. Corneal thickness and IOP levels did not correlate in pregnant patients. Krukenberg spindles are also more common in pregnant patients but tend to decrease in size during the latter part of pregnancy and into the post- partum period. Although VF changes can occur, these are likely transient. The au- Source: Gilbert Rondilla Photography/Getty Images O phthalmologists 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 vi- sual 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 condi- tions 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 my- opic levels returning to near pre- thors wrote the "rarity of glaucomatous visual field defect in the temporal visual field and the reversibility of any kind of visual field defect after pregnancy are important clues in differentiating glaucomatous from preg- nancy-induced visual field defect while following a pregnant glaucoma- tous patient."3 Low blood pressure may result in a higher risk of glaucoma progres- sion. Transient hypotension and an increased risk of glaucoma progres- sion may occur if there are large quantities of blood loss during labor. Little information is available about the safety of anti-glaucoma med- ications on the fetus; most glaucoma medications fall into Category C, and it is unlikely human trials will be forthcoming. Antimetabolites (mitomycin C and 5-fluorouracil in particular) have teratogenic properties and should be avoided in pregnant patients. The only two glaucoma medications in Category B—brimonidine and dipivefrin—are not recommended for use during breastfeeding. If necessary, glaucoma surgery under topical anesthesia can be performed with little risk of systemic exposure to the fetus. Here, a synopsis of some

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