April 27, 2022

The most important ophthalmology research updates, delivered directly to you.

In this week's issue

  • Rates of same-day cataract surgery are very low, and certain demographic factors (race, rural location) were associated with increased use
  • Patients with NF1 have increased bright peak / dark trough ratios using EOG, corresponding to possible RPE melanocytogenesis dysfunction
  • A quality improvement study at Stanford was able to shorten average time to appointment for ophthalmology patients seen in the ER

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Who gets same day cataract surgery?


You’ve heard the expression 2 birds with 1 stone…what about 2 eyes in 1 day? In this retrospective cohort study of nearly 2 million Medicare patients over the past decade, investigators sought to determine factors associated with undergoing immediate sequential bilateral cataract surgery (ISBCS) versus delayed sequential bilateral cataract surgery (DSBCS). Of the 2 million cases, only about 0.2% were ISBCS. Factors associated with increased ISBCS included Black, Asian, and Native American race (versus White), rural residents (versus urban), undergoing surgery in a hospital (versus ambulatory), bilateral complex cataracts (versus noncomplex), and having ocular comorbidities (such as glaucoma and maculopathy). The rates of endophthalmitis and cystoid macular edema were similar between those undergoing ISBCS and DSBCS, suggesting comparable safety profiles. Noting the above demographic and socioeconomic factors associated with its use, future studies are needed to determine if ISBSC can improve health equity. Furthermore, given the low rates of ISBCS, the investigators argue for increased access to ISBCS.  

Optimizing the Emergency Department Follow-Up Workflow

JAMA Ophthalmology

Emergency departments are not the place for phone tag! Scheduling outpatient follow-up is a critical step to ensure favorable outcomes following the emergency treatment of certain ocular pathologies. Researchers designed interventions around key gaps: a standardized consult note template, ophthalmology clinic nurses acting as centralized points of contact to and reserving appointment slots for emergency room cases to overcome scheduling issues, case-by-case overrides of financial approval for patients, and standardizing patient discharge instructions. The group then compared the time from referral to scheduling in the five weeks prior to intervention to the five weeks post-intervention. Results showed a decrease in mean scheduling time from 2.8 to 1.3 days (95% CI, 0.10-2.74, P = 0.02). Furthermore, in qualitative analysis, ophthalmology clinic staff reported less frustration, fewer electronic medical record messages, and residents felt the interventions required minimal increased work. The success of these interventions demonstrates how process improvement approaches can be customized to individual institutions and create a more efficient workflow. 

Investigating the Retinal Pigment Epithelium in NF Type 1


Lisch nodules and optic nerve glioma are two ophthalmologic findings in NF1, but how are the retina or choroid affected? The clinical diagnosis of NF1 historically has relied on two key ophthalmologic findings: Lisch nodules and optic nerve glioma. Recently in 2021, the diagnostic criteria were revised to include the presence of two or more specific choroidal abnormalities. However, the nature of choroidal or retinal pigment epithelium (RPE) abnormalities in NF1 are poorly understood. Past studies have noted bright patchy areas on near-infrared imaging in the choroid of NF1 patients and EDI-OCT localized these lesions to the deep layer below the choriocapillaris. This prospective case-control study of 20 patients with NF1 and 10 healthy age-matched controls aimed to quantify the function of the RPE in NF1 using electro-oculography (EOG) and to determine whether the presence of choroidal abnormalities would correlate with RPE dysfunction. EOG light peak (LP) / dark trough (DT) ratio was significantly higher in NF1 patients, due to lower DT values. As EOG measures the differential potential in the RPE apical membrane, the researchers hypothesized that abnormalities could point to dysregulation of intracellular calcium concentration which is contained in melanosomes. Dysregulated melanocytogenesis is a known feature of NF1 and likely plays a role in inducing abnormal polarization in RPEs. While the study did not find a significant correlation between presence of choroidal abnormalities and EOG parameters, future studies could tease apart their relationship through a more longitudinal approach with older patient demographics. Overall, this study confirms the supra-normal LP/DT ratio seen in NF1 patients and provides insights into the potential mechanism for these findings.


Are chalazia associated with Demodex infestations?

JAMA Internal Medicine

Don’t tell your kids about the bugs in their eyes! Chalazia is a very common inflammatory lid disorder that when prone to recurrence, is difficult to prevent, especially in children. Known risk factors for chalazia include chronic conjunctivitis, blepharitis, excessive gland secretions, or vitamin A deficiency, however increasing studies on the incidence of eyelid Demodex infestations have been emerging. This prospective, observational, comparative study sought to analyze whether there is an association between presence of Demodex mites and chalazia incidence within a pediatric population. 446 children were enrolled in this study who had undergone surgical treatment for either chalazia or other ocular diseases and underwent eyelash sampling and microscopic Demodex examination. Demodex infestation was present in a significantly higher proportion of chalazia patients (52.19%) than control patients (0%) and was also associated with recurrent (p=0.002), multiple (p=0.023), and skin nodule (p=0.001) chalazia, as well as meibomian gland dysfunction (p-0.024). As chalazia can be a difficult disease to manage and can lead to chronic inflammation of the skin and hair follicles, Demodex testing and eradication may be effective in treating and preventing recurrence of chalazia in certain pediatric patients. 


Deep Learning Algorithms to Identify Fungal and Bacterial Keratitis 


Looks like someone read the textbook. Microbial keratitis is an urgent ophthalmic condition that requires prompt intervention to maximize best outcomes. This retrospective study aimed to use a deep learning algorithm to successfully identify and distinguish between fungal and bacterial keratitis, as culture can take time to result. A total of 1159 bacterial and 673 fungal keratitis were used to train the model, and 335 images were used for validation and testing of three pre-trained convolutional neural networks (VGG19, DenseNet121, RestNet50). The classification performance in F1 score (measure of test accuracy) was highest for VGG19 (0.78), followed by DenseNet121 (0.71), and RestNet50 (0.68). VGG19 also demonstrated the highest area under precision-recall curve of 0.86. Convolutional neural network with ensemble learning demonstrated the best performance in discriminating fungal from bacterial keratitis compared with single architecture models. Thus, this model of deep learning algorithm can serve as an adjunctive resource for quickly diagnosing microbial keratitis. This tool has particular implications for developing countries that have limited access to subspecialists and laboratory facilities. 

End of Month Quiz

A 75-year-old man is referred to the ophthalmologist due to subjectively poor vision. He says that the center of his vision is worst, and occasionally turns his head sideways when talking with you. VA OD 20/200, OS 20/60. No notable findings from pupils, pressure, and anterior segment exam. Fundus exam OD is shown below. OS shows a smaller area similar to the right eye. 
Which of the following would be the most appropriate next step in management of the patient?
A. Pars plana vitrectomy
B. Anti-VEGF injections
C. AREDS2 vitamin supplementation
D. Aggressive diabetes management

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Quiz Answer: C
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