[Influence of pregnancy on refractive parameters after LASIK surgery]

Laser in situ keratomileusis and surface ablation in pregnancy

PURPOSE

Although corneal refractive surgery is contraindicated during pregnancy, some patients are unaware that they are pregnant when they undergo surgery. Our objectives were to determine the functional outcomes of corneal refractive surgery during pregnancy and to compare the results with those of nonpregnant women.

METHODS

We performed a multicenter, retrospective, interventional case series review of patients who were pregnant and who underwent laser in situ keratomileusis (LASIK) or surface ablation (photorefractive keratectomy, PRK) from September 11, 2002 to December 12, 2020 (group 1, n=82 eyes). Patients were included consecutively. Findings were compared with those of nonpregnant women (group 2, n=164 eyes). Functional (visual and refractive) outcomes are described. Follow-up was at least 550 days (control group, median [IQR], 990 days [715-1496]; study group, 895 days [709-1310]). The setting was Clínica Baviera, Spain, (AIER Eye Hospital Group).

RESULTS

A statistically significant difference was found between the groups in terms of efficacy index (EI). No complications of pregnancy or labor were reported. Similarly, a search of medical records revealed no adverse effects in the infants.

CONCLUSIONS

To the best of our knowledge, this is the first case series on pregnancy and refractive surgery. We do not recommend performing LASIK or surface ablation on pregnant women. Our objective in the present study was to present relevant scientific data obtained from women who underwent refractive surgery while unaware that they were pregnant.

Laser-Assisted In Situ Keratomileusis (LASIK) Enhancement for Residual Refractive Error after Primary LASIK

Background: To evaluate the safety, efficacy, and predictability of laser-assisted in situ keratomileusis (LASIK) enhancement after primary LASIK and compare to Food and Drug Administration (FDA) criteria. Methods: Patients who underwent LASIK enhancement after primary LASIK between 2002 and 2019 were compared to those who underwent LASIK without retreatment. Patient demographics, preoperative characteristics, visual outcomes, and postoperative complications were compared between groups. Epithelial ingrowth (EI) development was stratified based on duration between primary and secondary procedures. Results: We compared 901 eyes with LASIK enhancement to 1127 eyes without retreatment. Age, sex, surgical eye, sphere, cylinder, and spherical equivalent (SE) were significantly different between groups (p < 0.05). At 12 months post-enhancement, 86% of the eyes had an uncorrected distance visual acuity of 20/20 or better and 93% of eyes were within ±0.50 D of the target. Development of EI (6.1%) demonstrated an odds ratio of 16.3 in the long-term compared to the short-term (95% CI: 5.9 to 45.18; p < 0.0001). Conclusions: Older age at primary LASIK, female sex, right eye, and larger sphere, cylinder and SE were risk factors for enhancement. Risk of EI significantly increased when duration between primary and enhancement procedures exceeded five years. LASIK enhancements produce favorable outcomes and meet FDA benchmarks for safety, efficacy, and predictability.

Laser refractive surgery in pregnant or breastfeeding patients

This systematic review reported the outcomes of laser corneal refractive surgery in pregnant or breastfeeding patients. This study was performed by searching in PubMed, Web of Science, and Scopus databases, on June 15, 2020. Included were 128 eyes from a total of 64 patients, with the mean maximum follow-up was 39.2 ± 36.14 months. Time from surgery to complication ranged from 1 to 67 months, with a mean value of 23.42 ± 22.23 months. Photorefractive keratectomy and laser in situ keratomileusis surgery seem to be stable procedures that are not modified during pregnancy and safe to complete during breastfeeding. Nevertheless, the lack of weight prospective research avoids having a greater certainty on this matter, and because of transitory nature of pregnancy and breastfeeding, it could still be contemplated that surgery risk outweigh the benefits. Additional investigation will be necessary to clarify these issues.

Should I Get LASIK If I'm Breastfeeding?

Changes in keratometric values and refraction can occur during pregnancy. For this reason, changing a patient's refractive prescription or undergoing corneal refractive surgery is not recommended during pregnancy. However, the extent to which these corneal changes persist during lactation is not as well reported. Pregnancy and lactation lead to hormonal changes that affect the corneal structure. LASIK, or other types of refractive surgery, is not recommended until all of the following conditions are met: cessation of lactation, the return of regular menses, and a return to pre-pregnancy refraction. Additionally, patients should be cautioned that refractive regression may occur if they become pregnant within 1 year of LASIK. FUNDING: Research to Prevent Blindness, NY, USA.

Pregnancy-induced Changes in Corneal Biomechanics and Topography Are Thyroid Hormone Related

PURPOSE

To identify biomechanical and topographic changes of the cornea during pregnancy and the postpartum period and its association to hormonal changes.

DESIGN

Prospective single-center observational cohort study.

METHODS

Participants were 24 pregnant women (48 eyes), monitored throughout pregnancy and after delivery. Biomechanical and topographic corneal properties were measured using the Ocular Response Analyzer (ORA) and a Scheimpflug imaging system (Pentacam HR) each trimester and 1 month after delivery. At the same consultations blood plasma levels of estradiol (E2) and thyroid hormones (TSH, T3t, T4t) were also determined. A factorial MANCOVA was used to detect interactions between hormonal plasma levels and ocular parameters.

RESULTS

Significant differences in corneal biomechanical and topographic parameters were found during pregnancy in relation to T3t (p = .01), T4t (p < .001), T3t/T4t (P = .001), and TSH (p = .001) plasma levels. E2 plasma levels (p = .092) and time period of measurement (p = .975) did not significantly affect corneal parameters. TSH levels significantly affected the maximal keratometry reading (p = .036), the vertical keratometry reading (p = .04), and the index of height asymmetry (p = .014). Those results persist after excluding hypothyroidism patients from the statistical analysis.

CONCLUSIONS

Hormonal changes affecting corneal biomechanics and topography during pregnancy could be thyroid related. Dysthyroidism may directly influence corneal biomechanics and represents a clinically relevant factor that needs further investigation.

Plasminogen activator activity in tears of pregnant women

Purpose

Plasminogen activator activity (PAA) in tears of pregnant women was investigated at various gestation times to assess the availability of plasminogen activator for aiding potential corneal wound healing processes during pregnancy.

Methods

PAA was measured by a spectrophotometric method. The analysis used 91 tear samples from pregnant and non-pregnant women, supplemented with 10 additional tear PAA measurements from non-pregnant women obtained in a previous study.

Results

Tear levels of PAA in pregnant women formed a bimodal distribution. Either the tear PAA level was zero or non-zero during pregnancy. When non-zero, the tear PAA level was dissociated from gestation time and not different than non-pregnant and post-pregnant levels. The frequency of occurrence of zero level tear PAA increased with gestation: 16%, 17% and 46% had zero tear PAA in samples taken from women in the first, second and third trimester, respectively.

Conclusions

Overall, of the tear samples taken from women during pregnancy, a total of 26% were at zero tear PAA. The remaining tear samples had non-zero tear PAA values throughout gestation equivalent to non-pregnant tear PAA values, suggesting local control of the source of PAA in tears. Given the importance of the plasminogen activator system in tears to wound healing in the cornea, and the high occurrence of zero tear PAA in our sample of pregnant women, elective corneal surgery would be contraindicated. If corneal surgery is nevertheless necessary, the tear PAA level would be worth checking and patients with low level should be closely observed during the postoperative period.