Lynda Charters

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Polish investigators led by Dr Michal Orski, PhD, Department of Ophthalmology, Ludwik Rydygier Memorial Specialized Hospital, Krakow, Poland, reported that fractionated robotic radiotherapy of the tumours applied near the optical pathway is safe and does not impact vision despite minor changes in the anatomy of the optic nerve.

Dr Orski and colleagues undertook a prospective observational study of patients who had been irradiated using the CyberKnife system (Multiplan 4.6 Accuray, Sunnyvale, California, USA) to treat benign tumours. 

Patients had a variety of pathologies that included 10 with cavernous sinus meningioma, 9 with pituitary adenoma, 5 with meningioma of the anterior and middle cranial fossa, 5 with meningioma in the region close to optic chiasm, 3 with craniopharyngioma, and 2 with orbital meningioma, the authors described.

All patients received 3 fractions in doses from 600 to 800 centigray. The investigators used the pre-treatment baseline as the control follow-up examinations after radiotherapy. They then assessed the impact of the radiation on the eye based on anatomic and functional changes.

The anatomic features that were evaluated where the ocular surface, central corneal thickness (CCT), endothelial cell density (ECD), lens densitometry, central macular thickness (CMT), and retinal nerve fiber layer (RNFL); the functional features evaluated were the best-corrected visual acuity (BCVA), intraocular pressure (IOP), visual field (VF), and visual-evoked potentials (VEP).

Patients underwent ophthalmologic examinations before radiotherapy and 6, 12, 18, and 24 months after radiotherapy.

“We did not observe any significant changes in BCVA, IOP, CCT, CMT, VF, VEP, and slit-lamp examination during the 2-year observation,” the authors reported.

They did see significant decreases in the ECD and RNFL at all of the evaluations. The decrease in the cell density did not impact the corneal function and vision; the decrease in the RNFL did not impair visual function, they pointed out.

The investigators concluded, “Fractionated robotic radiotherapy of the tumours close to the optical pathway is safe and does not impair patient’s vision. Minor changes found in optic nerve anatomy (RNFL thinning) might be related to the radiation effect or tumour compression. The causal relation between low doses of radiation delivered to the cornea and the observed significant but slight decrease in ECD is uncertain. The observed changes did not cause visual disturbances perceivable by the patients.”

Orski M, Tarnawski R, Wylegala E, Tarnawski D. The impact of robotic fractionated radiotherapy for benign tumors of parasellar region on the eye structure and function. 

Articles

The investigators set out to study if treatment of the tumours close to the optical pathway is safe and whether it may impair a patient’s vision.

Exploring robotic fractionated radiotherapy for benign ocular tumours

An international team of researchers reported that atropine drops should be discouraged as a standard therapy after trabeculectomy because of the resultant greater and longer lasting reduction in visual quality.

 Dr Panagiotis Laspas, MD, from the Department of Ophthalmology, University Medical Center, Johannes Gutenberg-University Mainz, Mainz, Germany, was the lead study author.

The investigators explained that atropine has cycloplegic and mydriatic properties, the latter of which that can cause multiple visual side effects,

 including disrupted accommodation, blurred vision, haloes, and light sensitivity. The potential systemic absorption of the drug can affect the cardiovascular system,

 causing dysrhythmias, and affect patients’ mental state, causing confusion, restlessness and emotional lability.

They conducted a prospective randomised study of 40 patients who underwent standard trabeculectomy with mitomycin C at the Department of Ophthalmology Department, University Medical Center of Mainz. Postoperatively, all patients received ofloxacin and dexamethasone eye drops. The patients then were randomised into 2 groups of 20 patients each; 1 group (the intervention group) also received atropine eye drops postoperatively and were instructed to instill the drops 3 times daily for 2 days to stabilise the anterior chamber. All patients completed a visual quality questionnaire preoperatively and 2 and 6 weeks postoperatively.

The results showed that visual quality decreased postoperatively in all patients.

The authors reported, “Patients who received atropine eye drops described a greater and longer-lasting reduction in visual quality than those who did not receive atropine eye drops. Trabeculectomy often leads to a transient reduction in visual quality. This reduction was greater in severity and duration in patients who received postoperative atropine eye drops.”

Based on the results, the investigators suggested that “unless there is an underlying medical necessity, we would discourage the application of atropine as a standard therapy for trabeculectomy surgery.”

Laspas P, Maier E, Schuster A, et al. Effects of postoperative atropine eye drops on visual quality in patients undergoing trabeculectomy. 

Joachimsen L, Farassat N, Bleul T, et al. Side effects of topical atropine 0.05% compared to 0.01% for myopia control in German school children: A pilot study.

Merli GJ, Weitz H, Martin JH,et al. Cardiac dysrhythmias associated with ophthalmic atropine.

Jimenez-Jimenez FJ, Alonso-Navarro H, Fernandez-Diaz A, et al. Neurotoxic effects induced by the topical administration of cycloplegics. A case report and review of the literature. 

Unless there is an underlying medical necessity, researchers discourage the application of atropine as a standard therapy for trabeculectomy surgery in a recent study.

Atropine instillation after glaucoma surgery may impair vision, prolong rehabilitation time

 found that the disparities in access to ophthalmologic care for paediatric patients have increased over the past 15 years and are associated with lower socioeconomic status, according to Hannah Walsh, BS, and colleagues. She is from the University of Miami Miller School of Medicine in Miami, Florida, USA.

The investigators underscored the importance of accurate, publicly available online databases to identify the nearest paediatric ophthalmologists.

They commented, “The geographic distribution of paediatric ophthalmological care has not been reported since 2007; understanding this distribution could shed light on potential avenues to increase access, which is a necessary first step in addressing the paediatric ophthalmological needs of underserved areas.”

Ms Walsh and associates conducted a cross-sectional study to analyse the geographic distribution of paediatric ophthalmologists relative to the US population demographic characteristics. They used public databases from the American Academy of Ophthalmology and American Association for Pediatric Ophthalmology and Strabismus to identify the locations of US paediatric ophthalmologists as of March 2022.

Locations and numbers of paediatric ophthalmologists

The analysis identified 1,056 paediatric ophthalmologists, most of whom were in the most highly populated states: California (11.0%), New York (9.2%), Florida (6.5%) and Texas (5.9%).

“A total of 2,828 of 3,142 counties (90.0%) and 4 of 50 states (8.0%) had no paediatric ophthalmologists. In 314 counties (10.0%) with 1 or more paediatric ophthalmologists, the mean number of paediatric ophthalmologists per million persons was 7.7 (range, 0.4-185.5),” the investigators reported.

Household income was a factor, in that the counties with 1 or more paediatric ophthalmologists had a higher median household income compared with counties with 0 paediatric ophthalmologists ($70,230.59 vs $53,263.62, respectively), a difference that reached significance (

Other factors identified were the proportions of families in each county without internet access (8.0% vs 4.7%, 

 < 0.001), patients younger than 19 years without health insurance (5.7% vs 4.1%, 

 < 0.001), and households without vehicle access (2.1% vs 1.8%) (

 = 0.001) in counties with no compared with counties with 1 or more paediatric ophthalmologists.

The authors emphasised that disparities in geographic access to paediatric ophthalmologists persisted in 2022, and the range of practitioner to million persons has increased since 2007. Disparities in practitioner distribution were associated with lower socioeconomic status. Accurate publicly available information on the locations of paediatric ophthalmologists is warranted to increase access to care.

Walsh HK, Parrish A, Lucko L, et al. Access to pediatric ophthalmological care by geographic distribution and US population demographic characteristics in 2022. 

 Published online January 26, 2023. doi:10.1001/jamaophthalmol.2022.6010

Accurate publicly available information on the locations of paediatric ophthalmologists is warranted to increase access to care.

Understanding disparities in availability of paediatric eye care: US report

Progress is being made in the treatment modalities for inherited retinal diseases. Specifically, the delivery of lipid nanoparticle (LNP)-based mRNA seems promising to treat these diseases, according to Marco Herrera-Barrera, MD, from the Department of Pharmaceutical Sciences, College of Pharmacy, Robertson Life Sciences Building, Oregon State University, Portland, USA.

Until now, LNP-mediated mRNA delivery could only be achieved to the retinal pigment epithelium (RPE) and Müller glia. “LNPs must overcome ocular barriers to transfect neuronal cells critical for visual phototransduction, the photoreceptors,” the investigators explained.

They hypothesised that chemically decorating LNPs with a short 7-nucleotide oligomer peptide would facilitate penetration into the neural retina. Previous studies have shown that by crossing biologic barriers, peptides enhanced drug delivery, imaging agents and nanoparticle drug targeting.

In this study, they used a peptide library to identify peptide sequences that bind the neural retina in vivo. Decoration of the peptides on the surface of LNPs with varying surface densities resulted in successful delivery of mRNA to the neural retina in a mouse model, they reported.

“These results translated to the more clinically relevant nonhuman primate, where robust protein expression was observed in the photoreceptors, Müller glia, and RPE. Overall, we identified peptide-conjugated LNPs that can facilitate the delivery of mRNA to the neural retina, expanding the utility of LNP-mRNA therapies for inherited blindness,” they concluded.

Herrera-Barrera M, Ryals RC, Gautam M, et al. Peptide-guided lipid nanoparticles deliver mRNA to the neural retina of rodents and nonhuman primates. 

Albertini B, Mathieu V, Iraci N, et al. Tumor targeting by peptide-decorated gold nanoparticles. 

Hennrich U, Kopka K. Lutathera: The first FDA- and EMA-approved radiopharmaceutical for peptide receptor radionuclide therapy. 

The delivery of lipid nanoparticle-based mRNA to the retina is encouraging, according to researchers.

Author | Lynda Charters

Articles

Atropine instillation after glaucoma surgery may impair vision, prolong rehabilitation time

Understanding disparities in availability of paediatric eye care: US report

Inherited retinal diseases: Progress being made with treatment modalities

Exploring robotic fractionated radiotherapy for benign ocular tumours