Gastric Bypass Improves Microvascular Perfusion in Patients with Obesity.

PURPOSE: Basic science research has shown that obesity is associated with microvascular endothelial dysfunction. However, whether bariatric surgery impacts the microvascular networks has yet to be explored. This study sought to evaluate the impact of gastric bypass in the retinal microvasculature. METHODS: Patients with obesity (BMI ≥ 35 kg/m2) scheduled to gastric bypass were consecutively recruited and included in the study. Patients were evaluated before surgery and 6-12 months after the intervention. Macular microvascular properties were evaluated using optical coherence tomography (OCT) angiography. Foveal avascular zone area, perimeter, circularity, and foveal and perifoveal vascular density (in both superficial and deep vascular plexus) were computed. RESULTS: In total, 40 eyes from 20 patients were included (30% male, mean BMI 43.4 ± 4.5 kg/m2 (range 35.7-51.4). From these, 45% were diabetic before bariatric surgery. After surgery, there was a significant increase in foveal avascular zone circularity (from 0.85 ± 0.09 to 0.92 ± 0.07, p = 0.001) and vascular density in perifoveal deep vascular plexus (from 0.69 ± 0.12 to 0.73 ± 0.12; p = 0.04), whereas foveal avascular zone perimeter decreased (from 2.34 ± 0.37 to 2.20 ± 0.35 mm, p = 0.007). Preoperative diabetic status was not a predictor of microvascular retinal changes after bariatric surgery. However, after multivariate adjustments, the increased drop in HbA1c after the surgery remained associated with the increase in perifoveal vascular density in the deep vascular plexus (B = 0.05; 95% CI 0.05-0.10; p = 0.03). CONCLUSIONS: Gastric bypass improves retinal microvascular perfusion as demonstrated by the increased parafoveal vascular density in the deep vascular plexus, increased foveal avascular zone circularity, and decreased foveal avascular zone perimeter.

Bariatric Surgery Induces Retinal Thickening Without Affecting the Retinal Nerve Fiber Layer Independent of Diabetic Status.

PURPOSE: Obese patients have neurodegeneration of the optic nerve demonstrated by decreased peripapillary nerve fiber layer. Whether bariatric surgery reverses this neurodegenerative process has not been explored. We aimed to evaluate the impact of bariatric surgery in the structure of the retina and optic nerve. METHODS: Multicentric observational study. Obese patients scheduled for bariatric surgery were consecutively recruited and included in the study and evaluated before and 6-12 months after the intervention. The retinal structure was evaluated as retinal thickness in the different retinal layers in the foveal, perifoveal, and parafoveal regions using optical coherence tomography. Choroidal thickness and optic nerve retinal nerve fiber layer thickness were also evaluated. RESULTS: Eighty eyes from 40 participants were included. Globally, we found a significant thickening of the retina after bariatric surgery (foveal: 273.5 (21.5) µm vs 280.0 (28.8) µm, p < 0.001; parafoveal 332.4 ± 17.8 µm vs 336.6 ± 15.9 µm, p = 0.003; perifoveal: 293.4 ± 13.8 µm vs 295.7 ± 14.9 µm; p = 0.001), whereas no significant differences were found for the ganglion cell layer, choroid, or peripapillary nerve fiber layer thickness. The retinal thickening was confined to inner retinal layers and was independent of the diabetic status of the patients. After multivariate adjustment, HbA1c variation, preoperative C-peptide, preoperative hypertension, preoperative OSA, and preoperative LDL and TG levels seem to be clinical predictors of retinal thickening. CONCLUSIONS: We found a significant thickening of the retina after bariatric surgery that was independent of the diabetic status. The thickening was confined to inner retinal layers and may represent and improve perfusion. The peripapillary nerve fiber layer remained unchanged after the surgery.

Long-term refractive outcomes in children with early diagnosis of moderate to high hyperopia.

PURPOSE: The purpose of this study was to investigate the long-term outcome of moderate-to-high hyperopic refractive errors in childhood. METHODS: We reviewed medical records from children diagnosed with hyperopia (≥3D) in the amblyogenic risk factors screening that is performed in a public hospital in Portugal. We included hyperopic children diagnosed between 2001 and 2011 with at least three available ophthalmologic evaluations (including one before the age of 3 years and one after a minimum period of 6 years after the first evaluation). Spherical equivalent (SE) was considered. RESULTS: In total, 78 eyes from 39 children met the inclusion criteria (49% male). Mean age at first and last evaluation was 1.8 ± 0.9 years and 10.6 ± 2.7 years, respectively. Median follow-up was 130 months (range 72-193). At baseline evaluation, the mean SE was 4.5 ± 1.4 diopters, 36% of children had a SE ≥5.0 diopters, 23% had partially accommodative esotropia, 26% had accommodative esotropia and 51% had no eye deviation. At the last evaluation, the mean SE was 4.6 ± 1.7diopters. During follow-up, four children developed unilateral amblyopia (one because of anisometropia, three because of anisometropia and strabismus). From these, three recovered with treatment. Until the age of 10 years, the number of children that presented with strabismus did not decrease. CONCLUSION: In our study, children with moderate to high hyperopia did not experience a significant reduction in the power of the refractive error. Although almost 50% of children had an initial deviation, only one had amblyopia at the end of follow-up. Implementing screening strategies for the early detection of this refractive error may prevent long-term vision morbidity in hyperopic children.

Retinal Nerve Fiber Layer Thickness Decrease in Obesity as a Marker of Neurodegeneration.

BACKGROUND: Idiopathic intracranial hypertension (IIH) is a serious condition that is frequently associated with irreversibly vision loss, having a higher incidence among obese women. Our aims were to screen subclinical IIH in obese patients scheduled to bariatric surgery using peripapillary retinal nerve fiber layer (RNFL) thickness and to evaluate if the findings demand the possible need of a preoperative evaluation in this population. METHODS: This study included 111 eyes from 36 obese patients (86% female, body mass index > 35 kg/m2) scheduled to bariatric surgery and 20 non-obese (body mass index < 25 kg/m2) age-matched controls. We measured sectorial and mean RNFL thickness in a 3.5-mm-diameter circular scan centered on the optic nerve head, using optical coherence tomography (Heidelberg Spectralis SD-OCT) in all participants. Multivariate linear regression was used for adjustments. RESULTS: No patient had subclinical IIH corresponding to increased RNFL thickness. However, in obese individuals, global peripapillary RNFL was thinner than in controls (104 ± 6 µm versus 99 ± 12 µm, p = 0.005). Overall, RNFL thickness was superior in the control group for all sectors. The differences reached significance for the nasal, temporal, superior temporal, and inferior temporal sectors. These differences remained even after adjusting for possible confounders (hypertension, dyslipidemia, diabetes, age, sleep apnea syndrome, and sex). CONCLUSIONS: Routine screening asymptomatic obese patients undergoing bariatric surgery for IIH using RNFL thickness was not clinically relevant in our study. However, we found that severe obesity is associated with neurodegeneration independently of the other components of the metabolic syndrome, what may justify future investigation on the need of monitoring these patients.