Ophthalmologic evaluation of severely obese patients undergoing bariatric surgery: A pilot, monocentric, prospective, open-label study

Shedding light on eye disease in obesity: A review

Obesity is known to be associated with numerous ocular manifestations, including but not limited to, diabetic retinopathy (DR), age-related macular degeneration (AMD), cataracts, glaucoma, and dry eye disease. This review aims to provide an overview of the ophthalmological findings in obesity. A literature search was conducted using PubMed and Cochrane databases for studies describing randomized clinical trials, meta-analyses, systematic reviews, and observational studies published from 1 January 2017 to 1 April 2023. The search terms used included relevant keywords such as 'obesity', 'body mass index', 'waist-to-hip ratio', 'bariatric', 'ophthalmology', 'eye disease', 'myopia', 'retinopathy', 'glaucoma', and 'cataract'. This literature search was performed on 1 April 2023. Obesity is associated with increased risk of developing DR, a sight-threatening complication of diabetes mellitus. Similarly, obesity has been shown to increase risk of AMD, cataracts, glaucoma, and ocular surface disease. Multiple mechanisms linking obesity to ophthalmic disease have been proposed. Adipose tissue produces various inflammatory cytokines that can affect ocular tissues, leading to disease progression. Additionally, obesity is associated with systemic metabolic changes that can influence ocular health. Bariatric surgery has been shown to be protective against development of ophthalmic disease. Obesity is a significant risk factor for several ophthalmological diseases. Healthcare providers should encourage weight loss in patients with overweight or obesity to prevent or delay the onset of ocular complications. Further research is needed to better understand the underlying mechanisms of this association, and to identify effective strategies for preventing or managing ophthalmic disease in patients with obesity.

Impact of obesity on peripapillary choroidal thickness, macular choroidal thickness, and lamina cribrosa morphology

BACKGROUND

Obesity is known to be a significant risk factor for many ocular diseases. In order to understand the mechanism of obesity-related ocular diseases, we examined the lamina cribrosa morphology, peripapillary choroidal thickness (PPCT), and macular choroidal thickness (MCT) in obese women using optical coherence tomography (OCT).

METHODS

This comparative cross-sectional study included the right eyes of 72 obese women and 63 healthy women classified based on body mass index (BMI). Each participant underwent a thorough ophthalmological examination and enhanced depth (EDI) OCT imaging, including measurements of PPCT from a total of 12 regions, MCT from a total of 7 regions, Bruch's membrane opening (BMO), lamina cribrosa thickness (LCT), lamina cribrosa depth (LCD), intraocular pressure (IOP), and central corneal thickness (CCT).

RESULTS

The mean age and BMI of the obese group were 32.36±7.38 years and 35.11±4.39 kg/m², while those of the control group were 31.64±7.78 years and 20.88±1.72 kg/m² (p = 0.658, and p<0.001, respectively). PPCT N1000, PPCT N1500, PPCT S1500, and PPCT T1500 were statistically significantly thinner in the obese group than the control group (p values were 0.039, 0.012, 0.027, and 0.036, respectively). IOP and CCT were significantly higher in the obese group than the control group (p = 0.016, and p = 0.019, respectively). There was no statistically significant difference between the two groups in terms of MCT, BMO, LCT, and LCD.

CONCLUSION

We discovered thinning in the PPCT, which indicates microvascular abnormalities in the optic disc head. Microvascular alteration in the peripapillary region may be a potential initial event in the pathogenesis of several obesity-related ocular diseases, especially glaucoma.

How Does Weight Loss After Bariatric Surgery Impact the Ocular Parameters? A Review

Our review aimed to assess the effects of bariatric surgery-induced weight loss on ocular functions. We focused on retinochoroidal microcirculation, glaucomatous factors, and the condition of the eye surface pre- and postoperatively. The review covered 23 articles, including five case reports. Bariatric surgery positively impacts retinochoroidal microcirculation. The arterial perfusion and vascular density improve, venules constrict, and the arteriole-to-venule ratio increases. Weight loss positively correlates with intraocular pressure decrease. The impact of postoperative weight loss on the choroidal thickness (CT) and the retinal nerve fiber layer (RNFL) is still unclear. The correlation between ocular symptoms and hypovitaminosis A needs to be evaluated. Further research is required, especially regarding CT and RNFL, mainly focusing on long-term follow-up.

A Glaucoma Patient with an Intraocular Pressure Decrease following Total Gastrectomy and Postoperative Anticancer Treatment

We herein report a case of glaucoma with an intraocular pressure (IOP) decrease following total gastrectomy (TG) and anticancer treatment for gastric cancer. A 62-year-old male underwent trabeculectomy of the left and right eyes in August 2011 and July 2012, respectively. During the follow-up, IOP of the right eye was 9-12 mmHg (with bimatoprost, dorzolamide, and timolol maleate), and that of the left eye ranged between 14 and 26 mmHg (with bimatoprost, dorzolamide, timolol maleate, and brimonidine tartrate). In December 2014, TG was performed due to gastric cancer. After surgery, the patient received S-1+CDDP, weekly PAC, and CPT-11 therapies. The patient died on March X, 2017. Before TG, the body mass index (BMI) was 29.5 but decreased to 24.8 before the start of the two courses of weekly PAC therapy. IOP of the right eye was 6 mmHg (with bimatoprost), and that of the left eye was 10 mmHg (with bimatoprost, dorzolamide, and brimonidine tartrate), showing decreases. After the initiation of weekly PAC therapy, BMI was approximately 19. IOP of the right eye ranged between 6 and 10 mmHg until the final ophthalmological examination (January 11, 2017), while that of the left eye ranged between 8 and 15 mmHg. In this patient with glaucoma, IOP was not controlled by eye drop treatment, and TG for gastric cancer and postoperative treatment with anticancer drugs resulted in weight loss and a decrease in IOP.

Bariatric surgery-what the ophthalmologist needs to know

The incidence of bariatric surgery is increasing due to obesity being one of our top public health challenges. As such, bariatric-related ophthalmic changes are a potentially new clinical area of knowledge, with increasing published evidence on post-bariatric complications experienced by patients and identified by clinicians. We reviewed the available literature and summarised the different complications and potential recommendations. A search strategy was conducted with PubMed, Cochrane, Medline, Embase, Allied and Complementary Medicine and DH-DATA databases to look for papers answering our research question: "What are the ophthalmological complications for patients after bariatric surgery?". Our search gave a total of 59 relevant papers. Bariatric surgery, particularly subtypes that cause direct bypass of nutrients from the stomach, lead to nutritional deficiencies. Vitamin A, crucial for proper functioning of body systems and specialised cells, manifests ophthalmologically as corneal ulceration, nyctalopia, conjunctival xerosis and more. Thiamine levels are also depleted, leading to Wernicke's Encephalopathy. Pre-existing diabetic retinopathy is also noted to worsen sub acutely, although evidence is conflicting. Patients undergoing surgery to treat idiopathic intracranial hypertension would have reduced IOP and resolving papilloedema. Other comorbidities of obesity like HBA1C levels, obstructive sleep apnoea, and metabolic syndrome also resolve post-surgery. History taking remains the cornerstone of medical practice. From the evidence, we suggest consideration of pre-surgery screening for ophthalmic pathology and post-operative monitoring of disease progression. Real-world data needs to continuously be analysed to create definitive management pathways that can help clinicians recognise ophthalmic complications early, improving patient outcomes.

Spectral-domain OCT measurements in obesity: A systematic review and meta-analysis

Background

Previous studies proposed possible applications of spectral-domain optical coherence tomography (SD-OCT) measurements in prognosticating pathologies observed in overweight/obesity, including ocular, vascular, and neurologic consequences. Therefore, we conducted a systematic review and meta-analysis to investigate the changes in the in SD-OCT measurements of the patients with higher body mass index (BMI) compared to normal weight individuals.

Materials and methods

We conducted a systematic search on PubMed, Scopus, and Embase. The search results underwent two-phase title/abstract and full-text screenings. We then analyzed SD-OCT measurements differences in patients with high BMI and controls, and performed meta-regression, sub-group analysis, quality assessment, and publication bias assessment. The measurements included macular thickness, cup to disc ratio, ganglion cell-inner plexiform layer (GC-IPL) and its sub-sectors, RNFL and peripapillary RNFL (pRNFL) and their sub-layers, and choroidal thickness and its sub-sectors.

Results

19 studies were included in this meta-analysis accounting for 1813 individuals, 989 cases and 824 controls. There was an overall trend towards decreased thickness in high BMI patients, but only two measurements reached statistical significance: temporal retinal nerve fiber layer (RNFL) (Standardized mean difference (SMD): -0.33, 95% confidence interval (CI): -0.53 to -0.14, p<0.01) and the choroidal region 1.0 mm nasal to fovea (SMD: -0.38, 95% CI: -0.60 to -0.16, p<0.01).

Conclusion

Some ocular layers are thinner in patients with higher BMI than the controls. These SD-OCT measurements might correlate with adverse events related to increased body weight and have prognostic abilities. As SD-OCT is a robust, rapid and non-invasive tool, future guidelines and studies are needed to evaluate the possibility of their integration into care of the patients with obesity.

The association between bariatric surgery and cataract: a propensity score-matched cohort study

BACKGROUND

Obesity is considered a risk factor for cataracts. The association between weight loss and a cataract among patients with obesity has not been assessed to date.

OBJECTIVES

To assess the association between weight loss following bariatric surgery and cataracts.

SETTING

Nationwide Swedish healthcare registries between 2006 and 2019.

METHODS

We performed a population-based cohort study. Patients aged 40-79 years who underwent bariatric surgery were matched on their propensity score (PS) to up to 2 patients with obesity ("unexposed patients"). Cox proportional hazard regression analyses calculated hazard ratios (HRs) and 95% confidence intervals (CIs) of developing cataracts following bariatric surgery, compared with unexposed patients. Subgroup analyses by age, sex, bariatric surgery type, and duration of follow-up were conducted.

RESULTS

In total, 22,560 bariatric surgery patients were PS-matched to 35,523 unexposed patients. The risk of cataracts was decreased in bariatric surgery patients compared with unexposed patients (HR .71, 95% CI .66-.76). We observed the lowest risk of cataracts among bariatric surgery patients aged 40-49 years (HR .52, 95% CI .44-.75) but a null result for patients aged ≥60 years. Gastric bypass or duodenal switch were associated with decreased risks of cataracts, whereas sleeve gastrectomy yielded a null result. Subgroups of sex and duration of follow-up showed no evidence of effect modification (hazards were proportional throughout follow-up).

CONCLUSION

Our results suggest that substantial weight loss following bariatric surgery is associated with a decreased risk of cataracts, especially if bariatric surgery was performed before age 60.

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.

Subfoveal choroidal thickness and peripapillary retinal nerve fiber layer thickness in young obese males

OBJECTIVE

Regarding the effect of obesity on subfoveal choroidal thickness (CT) and peripapillary retinal nerve fiber layer (RNFL) thickness, controversial results have been reported in different patient groups. This study aimed to evaluate the effect of obesity on these parameters among young male subjects in comparison with age-matched non-obese healthy males.

METHODS

This prospective, cross-sectional study included both eyes of 50 obese young males and 50 healthy non-obese young males. The obese and the non-obese groups included subjects with a BMI of ⩾30 and ⩽25 kg/m², respectively. Subfoveal choroidal thickness and RNFL analyses were conducted by spectral domain optical coherence tomography (SD-OCT).

RESULTS

Subfoveal choroidal thickness (321.0 ± 46.7 vs 338.4±35.3, p = 0.002) and RNFL thickness at temporal quadrant (73.4 ± 9.9 vs 76.4 ± 9.3, p = 0.008) was significantly lower in the obese group when compared to the non-obese group. The groups did not differ regarding peripapillary RNFL thickness at other quadrants (superior, inferior, or nasal) or regarding mean peripapillary RNFL thickness.

CONCLUSION

Findings of this study demonstrated a negative correlation of obesity with subfoveal choroidal thickness and temporal quadrant peripapillary RNFL thickness. Larger studies on different patient groups with longer-term follow-up are warranted to better elucidate the ophthalmological effects of obesity.

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.