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JAMA Ophthalmology

Meta-Analysis: Comparison of Minimally Invasive Glaucoma Surgery Options  

Revolutionizing glaucoma care one millimeter at a time. Minimally invasive glaucoma surgery (MIGS) describes a relatively new group of interventions for intraocular pressure (IOP) control in open angle glaucoma. These surgeries typically involve the insertion of a perforated device, a few millimeters in length and even smaller in diameter, that encourages flow of aqueous humor from the anterior chamber. Compared to traditional incisional approaches, MIGS have fewer complications and are often performed alongside cataract surgery. However, their effect on IOP is relatively modest and evidence-based guidance for MIGS device selection is sparse. In a meta-analysis of six systematic reviews, investigators compared the likelihood of eyedrop-free glaucoma control and the degree of IOP reduction in patients who underwent MIGS with cataract surgery to those who had cataract surgery alone for three different MIGS devices. At 6-18 months post-op, each of the three devices showed an increased likelihood of patients remaining eyedrop-free (Hydrus: relative risk [RR], 1.6, 95% CI, 1.4 to 1.8; iStent: RR 1.4, 95% CI 1.2 to 1.6; CyPass: RR 1.3, 95% CI 1.1 to 1.5). IOP was significantly lower in patients who had Hydrus (-2.0 mmHg at >18 months post-op, 95% CI, -2.7 to -1.3 mmHg) or CyPass (-2.3 mmHg at 6-18 months post-op, 95% CI, -3.0 to -1.6 mmHg) compared to cataract surgery alone. These results indicate that MIGS may help improve IOP control and reduce the burden of eyedrops for patients with glaucoma. Although the Hydrus performed slightly better than the iStent and CyPass in this study, the effect sizes are small and further research is needed to help refine clinical recommendations. 

IOVS

FGF2 signaling effects on extraocular muscles

We’ve all heard the saying, “too much of anything is bad'' and this is certainly true when it comes to signaling pathways that control extraocular muscle structure and function. Over or underacting extraocular muscles (EOM) are a common cause of strabismus. Yet, the molecular drivers of these muscular changes are not well understood. Mutations in the fibroblast growth factor (FGF) receptor can result in strabismus and FGF’s role in muscle repair and maintenance is extensively studied in skeletal muscle. Researchers sought to determine the effects of FGF2 on extraocular muscle force generation and morphology. They employed a rabbit animal model for either short-term (1 week) or long-term (1, 2, or 3 months) treatment with FGF2 via injections into the superior rectus muscle. To quantify the effects of FGF2, these muscles were examined for force generation, myofiber size, and satellite cell (Pax7-positive) number. FGF2 treatment led to two distinctly different effects dependent on the time-course. Short-term treatments resulted in significant increases in EOM force generation, myofiber cross-sectional areas, and number of satellite cells, while long-term treatments led to decreases in all these parameters. These findings provide a direct connection between sustained FGF2 signaling in a variety of FGFR2-related craniosynostosis diseases highly associated with strabismus. The increased FGF2 signaling in diseases such as Apert syndrome are likely an underlying cause of EOM dysfunction in these patients. While short term treatments with FGF could be a promising therapy to increase EOM function, the duration of treatment should be strategically determined as “too much of anything is bad.”

American Journal of Ophthalmology

Cosmetic Contact Lens Corneal Infections

POV: You’re scrolling Insta, you see an ad for colored contact lenses. You don’t have a prescription, but you think to yourself: Will this get me more followers, or just a nice lil’ corneal infection? Cosmetic contact lenses are used solely for the purpose of changing eye color or enhancing eye appearance, and have gained popularity in the beauty industry. In this prospective, multicenter cross-sectional study, researchers sought to explore the incidence of cosmetic contact lens (CL)-related corneal infections in 8 South and East Asian countries. Because bacterial keratitis is well characterized in contact lens users wearing contact lenses for refractive errors, researchers were interested to see the incidence and characteristics of bacterial keratitis in cosmetic CL wearers. The study found that in 694 CL wearers with corneal infection, 204 were cosmetic CL wearers (29.4%) and 490 (70.6%) refractive CL wearers. Cosmetic CL users with corneal infections were generally young, female, and wearing hydrogel CLs. Infection with Acanthamoeba organisms were more common in cosmetic CL wearers. In summary, cosmetic CL infections represent a significant proportion of CL-related infections in Asia. Although we must further investigate the risks of cosmetic CL use, ophthalmologists should caution those who use these lenses.

JAMA Ophthalmology

Does glaucoma have an influence on gait and fall risk?  

They say that balance in life is key, but for glaucoma patients that may be a little easier said than done. Scientists across the nation studied whether glaucoma and visual field loss would have an impact on specific gait measures over a 3 year longitudinal span using baseline visual field damage (IVF). IVF was characterized as normal/mild (IVF >28 dB), moderate (IVF, 23-28 dB), and severe (IVF, <23 dB). Participants then walked across an electronic pathway measuring base of support, stride length, and steps per minute (cadence); these measures were tested every year. After comparing the measurements of gait over three years, this study found that worse IVF was associated with declines in stride velocity (-0.05 z score unit/year) and cadence (-0.07 z score unit/year). This was true even when stratifying by glaucoma severity. In particular, those with severe IVF loss had slower stride velocity and cadence. This was the first study of its kind to find a functional trajectory in patients with worsening glaucoma using objective outcomes. However, future studies need to account for factors such as polypharmacy and co-morbidities. Regardless, as falling is one of the leading causes of hospital admission for elderly patients, this study is extremely important in portraying the implications that uncontrolled glaucoma has on patient well-being and public health. 

Eye

International data: retinoblastoma sex ratio

Is biological sex associated with retinoblastoma? Retinoblastoma, the most common intraocular malignancy in children, is a rare disease associated with the RB1 gene on chromosome 13. Fabian et al. explored sex predilection for childhood eye cancer in the first international study of its kind. The sex ratio at birth of each participating country was obtained and comparisons were performed at a global level analyzing for differences in male and female age of diagnosis, familial incidence, and laterality of disease. Sample analysis of patients diagnosed with retinoblastoma in 2017 internationally suggests a male predominance of diagnoses with a sex ratio of 1.20, mainly found in Asia and India. The male predominance in India however may be attributed, in part, to gender-based discrimination in healthcare access and treatment. No sex differences were found in ages of diagnoses, stage of disease, and laterality. The study concluded that the observed sex ratio is likely due to gender constructs, rather than biological sex, underscoring the social, political, and cultural limitations afforded to girls. 

1. For children experiencing severe amblyopia, which of the following produced the greatest improvement in vision?

A. Atropine

B. Patching

C. Atropine and Patching

2. What did Enzor et al. find regarding Pseudomonas Aeruginosa Keratitis (PAK) in contact lens wearers vs. non-contact lens wearers?

A. PAK led to significantly lower visual acuities in contact lens wearers

B. PAK was significantly more common in contact lens wearers

C. PAK led to more cases of only light perception or no light perception vision in contact lens wearers

D. PAK was treated with surgery more commonly in contact lens wearers

3. True or False: subscribers were able to answer a significantly higher number of questions pertaining to information presented in The Lens.

A. True

B. False

4. In 11585 healthy eyes pooled from three studies, Black Americans on average had the:

A. Thinnest retinal nerve fiber layer and smallest cup-to-disc ratio

B. Largest cup-to-disc ratio and disc area

C. Greatest rates of retinal nerve fiber layer thinning

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