Given the expansion of laser trabeculoplasty and MIGS into early—sometimes initial—glaucoma management, understanding the long-term effectiveness of MIGS procedures and identifying patients most likely to benefit from them has important clinical implications. Angle-based MIGS options (canaloplasty, goniotomy, Trabectome, iStent) have grown substantially, although long-term efficacy is poorly understood. A new study based out of Massachusetts Eye and Ear in Boston analyzed angle-based MIGS effectiveness with/without preceding laser trabeculoplasty (SLT and argon laser trabeculoplasty). The team found that, while sustained IOP reduction was seen after angle-based MIGS in all groups, eyes that had laser trabeculoplasty prior were more likely to require reoperation. Their results were published in the journal Ophthalmology Glaucoma.

The study identified eyes that had undergone angle-based MIGS with/without prior SLT (< two years preceding MIGS) in the IRIS Registry over a six-year period. After propensity score matching, the study identified 954 eyes undergoing standalone angle-based MIGS and 7,522 undergoing angle-based MIGS and phacoemulsification.

For eyes only undergoing angle-based MIGS, those with prior SLT were more likely to undergo reoperation vs. those without laser trabeculoplasty at six and 12 months. In multivariate models, subjects with prior SLT were more likely to undergo reoperation over the 36-month period vs. those without it (adjusted hazard ratio: 1.53). For eyes undergoing MIGS + phacoemulsification, those with prior laser trabeculoplasty were more likely to undergo reoperation vs. those without laser trabeculoplasty at 12, 24 and 36 months. The researchers also identified that baseline IOP and glaucoma secondary to medications, trauma or inflammation were associated with higher hazard ratios for reoperation.

“Our work highlights the importance of understanding populations most likely to benefit from this type of MIGS and plays a role in informing treatment decisions, managing expectations and directing future research,” the researchers wrote in their paper. “While laser trabeculoplasty may provide initial IOP control, angle-based MIGS following prior laser trabeculoplasty may provide suboptimal results and the need for further surgery. Such information is useful in managing both surgeon and patient expectations.”

^{1. Mitchell W, Yang SA, Ondeck C, et al. Effectiveness of angle based minimally invasive glaucoma surgery after laser trabeculoplasty: An analysis of the IRIS Registry. Ophthalmol Glaucoma. March 20, 2024. [Epub ahead of print].}

Eye Finding Linked to Heart Attack

A recently described anatomical finding called retinal ischemic perivascular lesions (RIPLs), detected via OCT, is indicative of certain systemic cardiovascular conditions, as well as diabetes both with and without diabetic retinopathy and hypertension. More recently, they have been linked with cardiovascular conditions of coronary artery disease, atrial fibrillation and carotid artery stenosis. RIPLs are characterized by focal atrophy of the inner nuclear layer accompanied by secondary expansion of the outer nuclear layer, resulting in an undulating appearance of the middle retinal layers.

Since recent reports highlight that RIPLs can be useful in identifying subclinical cardiovascular disease, one new study wanted to determine if RIPLs are a marker of myocardial infarction (MI) in a cohort of patients with coronary artery disease (CAD). Researchers did indeed find such an association.

The retrospective investigation included 317 consecutive CAD patients who underwent spectral-domain OCT (SD-OCT).¹ Of all patients, 17 percent had a history of MI. A markedly higher prevalence of RIPLs was seen in the MI group at 59.3 percent compared with the non-MI group of 35.7 percent. After analysis, the researchers determined that presence of RIPLs was significantly associated with MI even after adjusting for age, sex, smoking status, hypertension, diabetes, dyslipidemia and BMI.

In their paper for the American Journal of Ophthalmology, the authors note that their findings are consistent with one previous study also reporting an observed higher (but not statistically significant) count of RIPLs in MI patients vs. those without. The present study confirmed these preliminary results in a larger patient base.

 Another prior investigation reported RIPLs were found in 90 percent of patients with mild hypertension and only in 17 percent of healthy participants. Similarly, RIPLs have been observed in diabetic patients with and without diabetic retinopathy, with one previous report showing 94.9 percent of patients with diabetic retinopathy and 53.8 percent without exhibiting them on OCT. However, this current study found equal hypertension and diabetes prevalence among patients with and without MI, suggesting these risk factors aren’t contributing to increased RIPL prevalence in the MI group.

The authors also elaborate on the association of smoking status with MI in their analysis. Only discordant results are currently available pertaining to cigarette smoking on retinal capillary plexus density. Despite this, one study has identified smoking as an independent risk factor for reduced retinal deep capillary plexus perfusion on OCT angiography.

Finally, the authors suspect that the pathophysiology of RIPLs in the setting of MI may be attributed to retinal hypoperfusion of the deep capillary plexus, either from microemboli formation or reduced ventricular ejection fraction.

Looking toward the future, the authors say, “should this association be confirmed by prospective studies, this would suggest that SD-OCT screening for RIPLs in CAD patients could be an important stratification tool for those at risk of developing MI.”

They add that the findings emphasize the critical role of RIPL detection in patients with coronary artery disease.

^{1. Bousquet E, Santina A, Au A, et al. Retinal ischemic perivascular lesions are associated with myocardial infarction in patients with coronary artery disease. Am J Ophthalmol. March 27, 2024. [Epub ahead of print].}

Consultations for Papilledema on the Rise

Once a relatively rare basis for consultation with a hospital emergency department or specialty practice, concern over suspected papilledema has grown in recent years. Many different factors are responsible for this ongoing change, including greater incidence of idiopathic intracranial hypertension (IIH), overreported radiologic signs of intracranial hypertension, strained access to outpatient neuro-ophthalmology services, poor insurance coverage and medico­legal concerns. These are all contributors to the lower threshold for emergency department visits for papilledema.

Consequently, one group of researchers wanted to examine the referral patterns and outcomes of neuro-ophthalmology ED and inpatient consultations for cases of concern for papilledema. Over one year, 153 consecutive patients were referred for concern of papilledema to a university-based subspecialty care center (Emory University) and underwent the institution’s standardized “papilledema protocol.”¹

After completing the protocol, it was determined that 58 percent of cases had bilateral optic disc edema, with 89 percent of those showing signs of papilledema (IIH). Of the 25 percent of the total consultations for suspected intracranial pressure without previous fundus exam, 74 percent did not have optic disc edema, 21 percent had papilledema and 5 percent had other causes of bilateral disc edema.

Of the 58 percent of consultations for presumed papilledema seen on fundus examination, 58 percent had confirmed papilledema, 17 percent had pseudopapilledema and 9 percent had other causes of bilateral optic disc edema. Of the 17 percent of patients with known IIH, five had papilledema and four required urgent intervention. Most diagnosed was IIH. Patients with secondary causes of IIH were on average older, men, not obese and more likely to have neurologic symptoms compared with IIH.

In total, the most common cause of bilateral disc edema was nonfulminant IIH in 64 percent of all referred patients without a previous diagnosis. The other 36 percent were diagnosed with a vision- or life-threatening disease, with 18 patients having papilledema from severe neurologic disorders.

The study authors note that “it is impossible to predict which papilledema patients will have a potentially severe cause of raised intracranial pressure without urgent brain imaging, and even in cases of newly diagnosed IIH, predicting which patients will have a poor visual outcome and require urgent multidisciplinary treatment is challenging, highlighting the need for urgent evaluation.”

Seven urgent surgical interventions were performed in this IIH cohort to prevent vision loss, including two optic nerve sheath fenestrations, two primary cerebrospinal fluid shunting procedures and three shunt revisions.

The authors continue, pointing out that “given the limited access to neuro-ophthalmologists, our study supports the need for ED access to expert eye-care providers or ocular fundus camera with remote interpretation of images for prompt identification of optic disc edema and standardized evaluation for neurologic emergencies such as with a ‘papilledema protocol.’ ”

Finally, they speculate that, in the future, implementation of nonmydriatic ocular fundus cameras and potential use of AI-assisted triage may allow for expedited workup in unspecialized health-care facilities.

^{1. Ray HJ, Smolar ALO, Dattilo M, et al. The increasing burden of emergency department and inpatient consultations for ‘papilledema’. J Neuroophthalmol. March 19, 2024. [Epub ahead of print].}

Childhood Obesity and IOP

In a recent study published in Journal of Glaucoma, a team in Turkey investigated the effect of obesity on corneal biomechanics as measured by Ocular Response Analyzer (Reichert), retinal nerve fiber layer and central macular thickness in children.¹

This prospective, cross-sectional, comparative study evaluated 146 eyes of normal-weight, overweight and obese children between the ages of six and 17 (43 boys and 30 girls). Mean age among the three groups was 12.5, 13.2 and 13.5, respectively. BMI percentile was found to be 44.5 percent, 88.8 percent and 98.7 percent, respectively.

They found that the mean IOP value was significantly higher in obese but not in overweight children; however, the mean hysteresis and corneal resistance factor values are significantly higher not only in obese but also overweight children. There was no statistically significant difference regarding age, sex, corneal compensated IOP, average RNFL thickness, cup-to-disc ratio or central macular thickness among the groups.

The researchers suggest the possibility that “excess weight may alter the composition or structure of the cornea, leading to changes in its biomechanical properties.”

The team did note that the biometric characteristics of the study eyes, such as central corneal thickness and axial length measurements, weren’t taken into account, which may have influenced the study outcomes. 

The researchers believed that their study underscores the importance of regular IOP and retinal assessments for early detection and management. “The significant elevation in corneal hysteresis and corneal resistance factor values observed in overweight children compared with those of normal weight implies that corneal biomechanics may be one of the parameters to be considered in the diagnosis and follow-up of these children,” they concluded. 

^{1. Eroglu SA, Unsal AIA, Verdi F, et al. The effect of childhood obesity on intraocular pressure, corneal biomechanics, retinal nerve fiber layer and central macular thickness. J Glaucoma. March 19, 2024. [Epub ahead of print].}