Formulation of a Peribulbar Block for Prolonged Postoperative Pain Management in Vitreoretinal Surgery: A Randomized Clinical Trial

Aerosolized, Gas-Phase, Intravitreal Methotrexate Reduces Proliferative Vitreoretinopathy in a Randomized Trial in a Porcine Model

Purpose

To determine the effectiveness of aerosol-delivered methotrexate (AD-MTx) in a large-animal (porcine) model of proliferative vitreoretinopathy (PVR).

Design

Prospective, randomized, interventional, double-masked, controlled, large-animal study with predetermined clinical and histopathologic outcome criteria.

Controls

Half of the pigs were randomly assigned to receive an identical volume of aerosol-delivered normal saline (AD-NS) using identical delivery systems and treatment intervals.

Methods

Proliferative vitreoretinopathy was surgically induced in 16 pigs (8 males and 8 females), randomly assigned to receive 2 doses (group A) or 3 doses (group B) of either AD-MTx (1.6 mg/0.4 ml) or normal saline (AD-NS). Group A pigs were euthanized at week 2 (n = 8), and group B pigs were euthanized at week 3 (n = 8). Masked clinical PVR scores (0-6) by a vitreoretinal surgeon and histopathology PVR scores (0-8) by a masked ophthalmic pathologist were used to determine outcomes.

Main Outcome Measures

The mean, combined clinical and histopathology scores (both anterior and posterior) were used to determine the overall treatment effect between the groups.

Results

The mean masked score (± standard deviation) when all grading end points (clinical + histopathology) were combined was a mean of 8.0 ± 2.3 in the AD-MTx group versus a higher 9.9 ± 2.0 in the AD-NS control group (P = 0.05). The clinical score was 3.88 ± 1.2 in the AD-MTx group versus 4.63 ± 1.6 in the AD-NS group (P = 0.16). The histopathology score for anterior PVR was 2.5 ± 0.8 in the AD-MTx group versus 2.5 ± 0.5 in the AD-NS group (P = 0.50), and the posterior PVR was 1.63 ± 1.6 in the AD-MTx group versus 2.75 ± 1.3 in the AD-NS group (P = 0.07). When the frequency of methotrexate dosing in group A (2 doses) was compared with that in group B (3 doses), the mean score was 8.75 versus 9.13 (P = 0.38), respectively, suggesting an insignificant difference.

Conclusions

After surgical induction of PVR in an aggressive, high-risk, large-animal model, AD-MTx reduced posterior PVR formation compared with AD-NS. Additional dosing at week 3 did not improve the outcomes. No difference in anterior PVR formation was noted with intervention. This novel drug delivery system has implications for PVR reduction and warrants further investigation.

Financial Disclosures

Proprietary or commercial disclosure may be found after the references.

Opioids and ophthalmology: review of the current literature

PURPOSE OF REVIEW

The number of opioid-related overdose deaths has rapidly increased since 2000, increasing more than five-fold from 1999 to 2016. Although surgeons only write 10% of opioid prescriptions annually, with ophthalmologists writing only a fraction of this amount, all physicians need to be cognizant of the current opioid epidemic and ways to decrease unnecessary opioid prescriptions.

RECENT FINDINGS

Previous work within ophthalmology has shown that retrobulbar anesthesia along with peri-operative intravenous or oral nonopioid analgesics can lead to decreased postoperative opioid use following ophthalmic surgery. Recent literature has shifted focus towards the use of opioid prescription guidelines in managing postoperative pain and decreasing the number of unnecessary opioids being prescribed by ophthalmologists. Overall, the frequency of opioid prescriptions may have gradually declined the past few years with such efforts, increased awareness, and new healthcare policies to monitor opioid prescriptions. However, ophthalmologists still continue to prescribe a substantial number of opioid medications, much of which may not be necessary.

SUMMARY

This review serves as a tool to aid all ophthalmologists in managing postoperative pain. There is a recent trend in addressing the opioid epidemic and efforts are being made to limit the overprescribing of opioids. Continued efforts are still required by all ophthalmologists to address the current opioid epidemic.

Transplantation of retinal pigment epithelium and photoreceptors generated concomitantly via small molecule-mediated differentiation rescues visual function in rodent models of retinal degeneration

Background

Age-related macular degeneration (AMD) is a result of degeneration/damage of the retinal pigment epithelium (RPE) while retinitis pigmentosa (RP), an inherited early-onset disease, results from premature loss of photoreceptors. A promising therapeutic approach for both is the replacement of lost/damaged cells with human induced pluripotent stem cell (hiPSC)-derived retinal cells.

Methods

The aim of this study was to investigate the in vivo functionality of RPE and photoreceptor progenitor (PRP) cells derived from a clinical-grade hiPSC line through a unified protocol. De novo-generated RPE and PRP were characterized extensively to validate their identity, purity, and potency.

Results

RPE expressed tight junction proteins, showed pigmentation and ciliation, and secreted polarization-related factors vascular endothelial growth factor (VEGF) and pigment epithelium-derived factor (PEDF). PRP expressed neural retina proteins and cone and rod markers, and responded to KCl-induced polarization. Transcriptomic analysis demonstrated an increase in the expression of mature retinal tissue-specific genes coupled with concomitant downregulation of genes from undesired lineages. RPE transplantation rescued visual function in RCS rats shown via optokinetic tracking and photoreceptor rescue. PRP transplantation improved light perception in NOD.SCID-rd1 mice, and positive electroretinography signals indicated functional photoreceptor activity in the host’s outer nuclear layer. Graft survival and integration were confirmed using immunohistochemistry, and no animals showed teratoma formation or any kind of ectopic growth in the eye.

Conclusions

To our knowledge, this is the first demonstration of a unified, scalable, and GMP-adaptable protocol indicating strong animal efficacy and safety data with hiPSC-derived RPE and PRP cells. These findings provide robust proof-of-principle results for IND-enabling studies to test these potential regenerative cell therapies in patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02134-x.

Impact of Standardized Prescribing Guidelines on Postoperative Opioid Prescriptions after Ophthalmic Surgery

PURPOSE

To determine the effect of implementing standardized opioid prescribing guidelines on prescription patterns for acute pain after ophthalmic surgery in opioid-naïve patients.

DESIGN

Quality improvement study.

PARTICIPANTS

Ophthalmic surgeons in an academic department of ophthalmology.

METHODS

Postoperative opioid prescribing patterns were compared before and after the implementation of standardized opioid prescribing guidelines for ophthalmic surgery at an academic institution. Only prescriptions provided to opioid-naïve patients 18 years of age or older were included. Surgeons reached a consensus for standardized prescribing guidelines appropriate for the type of surgery within their subspecialty. Guidelines were disseminated in conjunction with postsurgical pain management education to all ophthalmologists in the department, including trainees. The frequency of opioid prescriptions, the quantity of opioid prescribed (converted to oral morphine equivalent [OME]), and opioid prescription refill rates were compared before and after intervention.

MAIN OUTCOME MEASURES

Prescriptions with more than 80 OME, frequency of opioid prescriptions, mean OME, and refill rates.

RESULTS

Of 5349 ophthalmic surgeries performed during the 2 assessment periods, 196 (3.7%) were associated with opioid prescriptions for acute postoperative pain. The frequency of opioid prescriptions decreased to 3.0% (81/2736) after intervention compared with 4.4% (115/2613) before intervention (P = 0.005). When opioids were prescribed, the mean OME decreased from 93 (range, 27-500) before intervention to 42 (range, 14-100) after intervention (P = 0.003). The number of prescriptions for more than 80 OME decreased from 56 (2.1%) before intervention to 4 (0.1%) after intervention (P < 0.001). Based on the standardized guidelines, 103 of the 115 (89.6%) preintervention opioid prescriptions would not have adhered to the guidelines, whereas 39 of the 81 (48.1%) postintervention prescriptions did not adhere to the guidelines (P < 0.001). The proportion of refill prescriptions did not differ before and after intervention (P = 0.44).

CONCLUSIONS

The process of discussing postsurgical pain management and developing standardized opioid prescribing guidelines reduces overprescribing of opioids after ophthalmic surgery without increasing refill rates. Continued education is required to improve adherence to the prescribing guidelines further.

Drug Delivery to the Posterior Segment of the Eye: Biopharmaceutic and Pharmacokinetic Considerations

The treatment of the posterior-segment ocular diseases, such as age-related eye diseases (AMD) or diabetic retinopathy (DR), present a challenge for ophthalmologists due to the complex anatomy and physiology of the eye. This specialized organ is composed of various static and dynamic barriers that restrict drug delivery into the target site of action. Despite numerous efforts, effective intraocular drug delivery remains unresolved and, therefore, it is highly desirable to improve the current treatments of diseases affecting the posterior cavity. This review article gives an overview of pharmacokinetic and biopharmaceutics aspects for the most commonly-used ocular administration routes (intravitreal, topical, systemic, and periocular), including information of the absorption, distribution, and elimination, as well as the benefits and limitations of each one. This article also encompasses different conventional and novel drug delivery systems designed and developed to improve drug pharmacokinetics intended for the posterior ocular segment treatment.