January 11, 2023

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In this week's issue

  • Posterior pole changes associated with prolonged space travel seem to be distinct from similar changes seen in idiopathic intracranial hypertension.
  • A single resident’s cataract surgical experience shows the rate of increase in surgical speed and efficiency over time.
  • Bevacizumab appears to be superior to dexamethasone in terms of risk of progression to proliferative diabetic retinopathy in patients receiving treatment for macular edema.

Incidence and progression of chorioretinal folds during spaceflight

JAMA Ophthalmology

Sure, spacetime can fold, but so can your eyes. Prolonged spaceflight (12+ months) has been associated with a constellation of visual symptoms and ocular signs termed Spaceflight associated Neuro-Ocular Syndrome (SANS) that is of highly debated and likely multifactorial origin. SANS often causes induced hyperopia, disc edema, and chorioretinal folds in astronauts. With a potential to cause decreased visual acuity and metamorphopsia in future astronauts on long term missions, it is crucial to understand pathophysiology of SANS so as to prevent visually significant complications. This retrospective cohort study utilized OCT scans of the optic nerve head and macula of astronauts prior to and during spaceflight missions ranging from 6 to 12 months. The subjects had no systemic disease or ocular conditions predisposing them to chorioretinal folds or optic disc edema. Of the 72 eyes from 36 total crew members analyzed, chorioretinal folds were observed in 12 eyes. Early disc edema was seen in 10 eyes with choroidal folds, 4 with inner retinal folds, and 2 with peripapillary wrinkles. Macular choroidal folds developed in 6 eyes, and progressed with mission duration extending into the fovea although visual acuity was preserved in all cases. This study highlights that choroidal folds are the most common type of fold to develop during spaceflight, supporting previously reported studies suggesting that the pathophysiology in SANS is different than that of idiopathic intracranial hypertension.

Cataract practice makes perfect

American Journal of Ophthalmology

“Practice does not make perfect. Only perfect practice makes perfect”. Cataract surgery is one of the most frequently performed surgeries worldwide, and proficiency in the procedure is essential upon graduation from an ophthalmology residency. This study looked at a single resident’s recordings of their cataract surgeries during a year of residency training, measuring times of surgical steps and frequencies of relevant intraoperative actions as a surrogate for competency and skill progression. 100 videos of the resident’s 756 cases were randomly selected and analyzed. Overall procedure speed increased at a rate of 43 seconds per every 10 videos, especially in operative phases such as the main incision, phacoemulsification, and hydrodissection had the greatest improvements in speed relative to their average procedure time. Authors found a basic level of surgical competency is achieved after around 80 cases, while the next level of advancement towards ‘surgical finesse’ occurs after 300 cases, which is similar to the ACGME’s mandated minimum of 86 cataract surgeries during residency training.

BEVORDEX trial: bevacizumab vs. dexamethasone implants for diabetic macular edema, 5 years out

British Journal of Ophthalmology

BEVacizumab OR DEXamethasone… BEVORDEX… DEXORBEV? Diabetic macular edema (DMO) is managed with several methods, including intravitreal anti-VEGF agents and corticosteroids. The BEVORDEX study looked at outcomes for eyes randomized to either receive bevacizumab or dexamethasone (DEX-) implant throughout 2 years. Here, investigators examined longer term outcomes and complications following the original trial via retrospective chart review and 5-year follow-up visit. Data were available for 82% (n=72) of patients at 3 years and for 59% (n=52) patients at 5 years. Consistent with findings of the BEVORDEX trial, DEX-eyes had fewer treatments compared to bevacizumab-treated eyes (n=9.0 vs. n=19.2), with similar visual acuity gain, rates of subsequent cataract surgery, and central macular thickness reduction for both groups. However, DEX-randomized eyes were more likely to develop proliferative diabetic retinopathy compared to bevacizumab-randomized eyes (n=6 vs. n=1). Limitations of this study include loss of follow-up and potential changes in treatment patterns after conclusion of the original trial. Nevertheless, these findings provide long-term insight into the visual and anatomic outcomes, as well as rates of cataract surgery and proliferative diabetic retinopathy in eyes with DMO treated with dexamethasone implant or bevacizumab.


Prevalence of obstructive sleep apnea with floppy eyelid syndrome

Ophthalmic Plastic and Reconstructive Surgery

What do floppy eyelids have to do with sleep apnea? Floppy eyelid syndrome (FES) is a mechanical eyelid abnormality characterized by eyelid laxity, easy eyelid eversion, loss of eyelash parallelism, and papillary conjunctivitis. FES is highly associated with OSA, or obstructive sleep apnea. This systematic review and meta-analysis investigates the prevalence of OSA among patients with FES in 12 studies published between January 1997 and January 2022, and encompassing 511 patients. OSA was found to be prevalent in 57% of patients with FES, compared to 2 - 5% of the general population. Additionally, males encompassed 98% of patients and 70% of patients were diagnosed with OSA at the time of the study. Obesity was also present in 44% of patients diagnosed with FES. Given this strong association of OSA and FES, ophthalmologists should refer patients with FES for under or untreated OSA as this can be a life-threatening condition given its systemic health consequences.

Lens Landmarks

Is putting off the sweets worth the reward? The DCCT sought to understand whether tighter glycemic control would lead to better outcomes in diabetic retinopathy (DR). Prior to this study, there were limited cutoffs and guidance as to what Hemoglobin A1c levels and what type of insulin regimens were best for managing patients with Type 1 Diabetes. The DCCT randomized 1441 patients with Type 1 Diabetes to “intensive” versus “conventional” glucose control, and measured both the rate of retinopathy development (cohort 1) and retinopathy progression (cohort 2).

Key Points:
  • “Intensive” glycemic control led to a 78.5% risk reduction in the development of DR and a 64.5% risk reduction in the progression of DR in those who had mild-moderate NPDR
  • Across both treatment groups and both cohorts, lowering A1c led to significant reductions in the likelihood of DR development (10% A1c reduction led to 45% relative risk reduction) and DR progression (10% A1c reduction led to 43% relative risk reduction)
The DCCT (and the similar themed UKPDS for Type 2 Diabetes) illustrated across large sample sizes and randomized controlled trials the importance of tight glycemic control. Together, these two studies created a target goal for Hgb A1c < 7.0% for patients to avoid long-term ophthalmic complications from diabetes.

Question of the Week

You are consulted to evaluate a 60 year-old man with a recent history of liver transplantation who is complaining of a floater and pain in his right eye. He is admitted to the surgical ICU, and is receiving broad-spectrum antibiotics and total parenteral nutrition via a central venous catheter. Funduscopic examination reveals "fluffy" yellow-white lesions:
What is the most likely cause of this patient's symptoms?

A. Herpes Zoster Ophthalmicus
B. Infective Endocarditis
C. Candida Endophthalmitis
D. Herpes Simplex Keratitis

Keep scrolling for answer or click here

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