
During AAO 2020, Davinder Grover, MD, MPH, glaucoma specialist, Glaucoma Associates of Texas speaks on the highlights of his presentation regarding outcomes of a 12-year study comparing ab externo vs ab interno xen gel stents in tertiary glaucoma practice.


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Davinder Grover, MD, MPH, speaks on the highlights of his presentation regarding outcomes of a 12-year study comparing ab externo vs ab interno xen gel stents in tertiary glaucoma practice. 

(AAO) Comparing outcomes of xen gel stents in glaucoma practice

Sir Harold Ridley implanted the first IOL on February 8, 1950. Charlie Kelman’s US Patent for phacoemulsification was filed July 25, 1967.

Following the introduction of these foundational elements of modern 

, myriad incremental innovations has brought about what is surely the fastest, safest and most effective surgical procedure in the world today. 

These innovations include reducing the size and therefore the morbidity related to incisions, increasing the efficiency of lens extraction by optimizing the energy required to break up and evacuate the lens and improving the accuracy of 

 power calculations to refine postoperative refractive outcomes.




Small-aperture single-piece IOL could fill unmet need in patients

The development of adjunctive tools and tricks to alleviate the negative impact of pre-existing risk factors such as a small pupil or a weakened zonule has improved the safety of surgery, while the introduction of the femtosecond laser has created a new opportunity for innovation and precision in the treatment of astigmatism. All of these advances have combined to make a really big “wow” for our patients.

Clinical research has also produced important advances in our knowledge of cataract surgery. One of the most significant findings of recent studies of minimally invasive glaucoma surgery is confirmation of the substantial reduction of intraocular pressure in patients with mild to moderate glaucoma from cataract surgery alone. 

Investigational device exemption randomized clinical trials of both the CyPass and the Hydrus demonstrated a remarkable concordance in terms of the proportions of subject eyes in the control groups with unmedicated mean diurnal IOP reductions greater than or equal to 20% from baseline (57.8% compared with 58.0%) and the reductions in the control groups in unmedicated mean diurnal IOP from baseline (both -5.3 mmHg). 



Study results show that surgical system decreases IOP in patients with POAG


These clinically significant reductions in IOP in glaucoma patients having cataract surgery alone has now been demonstrated by randomized, controlled clinical trials which provide the highest standard of evidence for this phenomenon.

Nevertheless, challenges remain to provoke the imagination of scientists and entrepreneurs as global demographics predict an increasing demand for cataract surgery. 

For example, cystoid macular edema, or Irvine-Gass Syndrome, remains the most common complication associated with routine cataract surgery and can occur in patients with or without risk factors, such as diabetes or pre-existing macular disease. 

While topical anti-inflammatory agents are considered prophylactic in the perioperative period, the use of intravitreal anti-VEGF agents as treatment has garnered support. This unpredictable and potentially sight-threatening complication deserves attention. 

Another example of an unpredictable complication, capsule contraction syndrome, is related to fibrous metaplasia of lens epithelial cells similar to the pathogenesis of posterior capsular opacification and usually occurs within the first 3 months following surgery. 



Pre-operative IOP hints after cataract surgery



Changes in refraction may occur due to axial displacement or tilting of the 

due to the capsular contraction. 

Capsule contraction syndrome “has occurred in eyes with and without risk factors after the implantation of every IOL type (PMMA, silicone and acrylic).” 

Identified risk factors include small capsulorhexis diameter, postoperative inflammation, pseudoexfoliation syndrome, uveitis, retinitis pigmentosa, history of retinal surgery, myotonic dystrophy and diabetes.

Treatment of capsular contraction syndrome has relied primarily on Nd:YAG laser relaxing anterior capsulotomies to eliminate constriction. Radial capsulotomies “can significantly enlarge the anterior capsule opening” but “the IOL can remain decentered and folded within the capsular bag, especially in case of shrinkage or thick fibrous anterior membrane. ”Femtosecond laser capsulotomies have advantages in terms of precision, and, despite difficulty cutting thickened capsular tissue, are “easier and safer than previous techniques. ”



Minimize inflammation after cataract surgery

On a personal note, I remember the day during my junior year of residency when it suddenly dawned on me that my father had been left aphakic after his cataract surgery with Robert Sinskey, MD, the inventor of the Sinskey hook. I can recall seeing my father put in his contact using a pair of specially made glasses with only one lens. 

At that time, “the implant” was still very controversial, as Ralph Nader had testified against its use before the FDA. It was actually testimony from Robert Young, who played “America’s doctor” Marcus Welby on television, that supported the benefits of the 

. 

One patient, actor Robert Young, testified that at age 72 he is able “to see and work again thanks to the miraculous medical breakthrough” of a pair of these artificial lenses.

 development is that innovation is not for the weak of heart. Early phaco, just as much as early IOLs, did damage many eyes. Nevertheless, perseverance had great rewards, and it will no doubt continue to do so as we invent the next generation of cataract surgery innovations. 

, did damage many eyes. Nevertheless, perseverance had great rewards.

--- 


Packer is a consultant to Bausch + Lomb.

Articles

Innovations have made procedure quick, safe, effective.

The history of progress and innovation in cataract surgery


This article was reviewed by Kyle T. Packer, MD

Posterior chamber implantation of implantablecollamer lenses (ICLs) provided robust, stable results in a young population during an 11-year period. 

Most of the data are significant out to 8 years of follow-up, according to Kyle T. Packer, MD, who is with the US Army and practicing in Hanover, New Hampshire.

The results were garnered from a retrospective longitudinal study of 3004 eyes implanted with the ICLs at a US military treatment facility from 2008 to 2019. 



Robotics: Allowing surgeons to perform the seemingly impossible



All patients underwent standard refractive procedures and measurements preoperatively and postoperatively.

The median patient age was 25 years; 67% of patients were men. The median baseline spherical equivalent (SE) was –5.87 D.

Packer reported that the mean SE turned slightly myopic over the first 7 years postoperatively. The mean uncorrected visual acuity (UCVA) exceeded 20/25 and the mean best-corrected visual acuity (BCVA) exceeded 20/20 in all patients out to postoperative year 7.

ICLs were implanted in patients because of the presence of abnormal topography or moderate or high levels of myopia.

A comparison of the preoperative and postoperative BCVA showed that about 40% of patients had a gain of a minimum of 1 line of BCVA during the first year after implantation, indicating the safety of the ICLs.



Physicians' treatment decisions are reinforced with good data

The endothelial cell count decreased over time postoperatively compared with the baseline, which resulted in a significant overall decrease of 14.4% from baseline to the 5-year time point.

Patients had a significant increase in the IOP to the 1-year time point, and decreased from years 2 through 8.

The vault was estimated as a percentage of the corneal thickness. Low vaults were defined as less than 50% of the corneal thickness, ideal vaults from 51% to 200%, and high vaults over 200%. In this patient population, most vaults were considered ideal.

“The trend over time was a decrease in the vault size, especially after year 7, with no vault size over 157% of the corneal thickness,” Packer said.

Adverse events occurred in 1.2% during the 11-year follow-up, which included the formation of visually relevant cataracts, glaucoma, retinal detachment, and traumatic incision opening. The ICLs were removed in 4.5% of eyes in most cases because of low vaults.


Persistent retinal detachment connected to retinoblastoma


Physicians often use lenses due to abnormal corneal topography or high myopiaThe main takeaways from this study were the following: 

(1) ICLs were implanted because of abnormal corneal topography or high myopia; 
(2) refractive results associated with the ICLs were robust and stable during the long-term follow-up; 
(3) vault size decreased over time, which suggested an increased risk of cataract formation after 7 years; 
(4) a decrease in the mean endothelial cell count of about 14.4% at the fifth postoperative year suggested that another study is needed to assess the long-term clinical significance.

Physicians often use lenses due to abnormal corneal topography or high myopia

ICLs: Investigators finding robust and stable results over long term

Forty-five years have brought major changes to the field of 

. In 1975, retina fellowship training had existed for only about 26 years and there was only one subspecialty society, The Retina Society.

At that time, much of science and medicine was based on observation and training focused on surgical areas.

Over the ensuing four decades, there have been major advances in our understanding in science, technology, optics and medicine, as well as in surgery, which have tremendously changed the ways we diagnose and treat patients with retinal diseases.


Retinal implant improves quality of life in patients with RP

At that time, much of science and medicine was based on observation and training focused on surgical areas. 

Over the ensuing four decades, there have been major advances in our understanding in science, technology, optics and medicine, as well as in surgery, which have tremendously changed the ways we diagnose and treat patients with retinal diseases.

With an increased understanding of diseases and new treatments, areas of study within retina have grown and are now recognized as subspecialties in their own right, for example, pediatric retina, uveitis, and inherited retinal diseases. 

When considered among other medical or surgical specialties, ophthalmology/retina has accomplished firsts: development of optical coherence tomography, human gene therapy to treat an inherited disease, first FDA-approved method to use artificial intelligence to characterize retinal disease, as a few examples.

The evolution of genetics and molecular biology have led to recognition of gene associations with human diseases and the ability to study gene variants, as well as the signaling pathways involved, in the pathophysiology of a given disease. 

Tools including genetic knockout, inducible conditional and transgenic models have enabled scientists, clinicians, and clinician scientists to pursue study of molecules in specific cell types and how these influence human disease.



Harnessing regeneration of retinal tissues: An option almost within reach

Experimental methods led to the development of treatments: anti-angiogenic agents in retinovascular and choroidal neovascular diseases, immunosuppressive agents in uveitis, and gene therapy to treat some inherited retinal diseases as well as to understand complex pathophysiology of chronic diseases that potentially leads to future treatments. 

Now, blindness from a form of retinitis pigmentosa can be treated by replacing a mutant RPE65 allele with gene therapy. 

Clinical trials have evolved to test hypotheses developed from experimental studies, and then following interpretation of outcomes, to present new hypotheses to be studied experimentally (bench to bedside to bench model).

The development of optical coherence tomography has bridged pathology, once appreciated only after removal of an eye, to real-time by associating retinal pathology with visual acuity and human symptoms over time and following intervention. 

Advances in biomedical engineering have led to methods to restore vision through computer chips and to test cell and biomedical interfaces for future treatments.



AAO live: Autologous retinal transplant for larger macular holes gaining traction

It is impossible to list all the advances, but I will highlight a few. Diabetic retinopathy has evolved from preventing blindness to potentially reversing severity and improving vision. 

In 1981, success was reduction in 2-year incidence of blindness by 60% with panretinal photocoagulation. Over the next decades, laser maintained vision loss in DME

; then, anti-VEGF agents or steroids improved visual acuity and reversed disease severity in some patients. 

An FDA-approved camera using artificial intelligence to characterize DR severity is hoped to characterize features of the 60% of patients with DME who do not respond to current treatment.

In age-related macular degeneration (AMD), laser to choroidal neovascularization slowed progression to legal blindness, with success as maintaining visual acuity. Currently, anti-VEGF agents can improve vision in patients with neovascular AMD.

 

Clinical studies are identifying the burden of vision loss in atrophic AMD and clinical trials are testing new therapies for it.

Increasing recognition that surgical management of pediatric retinal diseases differs from other fields of ophthalmology has led to improved outcomes. 

In ROP, classification of early disease in the 1980s allowed testing of a destructive treatment of the peripheral avascular retina to reduce the hypoxic drive of abnormal angiogenesis first with cryotherapy and then laser.



Probe of IRIS registry: Anti-VEGF injections key treatment for PDR

Now, from experimental studies, anti-VEGF agents are used to regulate the VEGF signaling pathway and regress intravitreal growth of blood vessels and, for the first time, facilitate vascularization of the peripheral avascular retina. 

New studies are evolving to safely regulate angiogenesis in these fragile, developing premature infants so as not to adversely affect other organs, including the brain.

Surgical improvements include the development of small gauge vitrectomy and imaging. Microscopic surgery required flat contact lenses that afforded only a limited view of the posterior retina. 

Now wide-angle viewing systems permit a larger field of view; heads-up displays magnify images with stereopsis and better ergonomics for the surgeon; and intraoperative OCT allows visualization of vitreoretinal and subretinal layers, critical for surgery and gene therapy.

Therapies have evolved not only to be globe salvaging in certain tumors, but to preserve vision through chemotherapy, and increase understanding of molecular mechanisms involved to improve diagnostic prediction of tumor severity and recurrence.

When we look back at where we were, we realize that it has been a productive and amazing 45 years! The changes we see now seem to be increasing exponentially each decade. It is hard to predict what the future will hold from where we are now.



Mary Elizabeth Hartnett, MD, FACS, FARVO


Hartnett is a professor of ophthalmology at the John A. Moran Eye Center at the University of Utah in Salt Lake City.

Advances in treatment and surgical techniques have transformed patient care.  


Exploring four decades of change in retina

 surgery, dual-blade goniotomy and direct viscodilation of the collector channels with cataract surgery, effectively rejuvenates the outflow system that results in a dramatic increase in the number of eyes that do not require anti-glaucoma medications.

“The trabecular meshwork and collector channels are the conventional outflow pathway that is responsible for at least 50% of outflow resistance,” said Linda Burk, MD, clinical professor of ophthalmology at the University of Texas Southwestern Medical School in Dallas. “The question is: Can this pathway be rejuvenated?”




During consideration of an improved procedure, she described that the Kahook Dual Blade (New World Medical) can cut parallel incisions, minimize collateral damage, and does not leave trabecular meshwork leaflets in its wake that can lead to fibrosis. 

Burk noted that her previous trabecular meshwork specimens were characterized by loss of cells and collagen deposits.

Burk’s search for the improved procedure led to the combination procedure that included removal of the trabecular meshwork with use of the Kahook Dual Blade, which resulted in direct viscodilation of the collector channels and decreased hyphemas.


In this innovative technique, Burk uses the dual blade to “glide along” Schlemm’s canal to remove the trabecular meshwork. 

She adjusts the lens to open more of the canal. Generally, the trabecular meshwork comes out on the dual blade. Healon is injected to define the canal by holding the cannula snuggly against the back wall as more Healon is injected. 

At this point, Schlemm’s canal is now a “clean gutter.” The anterior chamber Healon and any residual debris then is removed. 



Traditional glaucoma surgery in the era of MIGS procedure


She explained that lowering the intraocular pressure (IOP) allows blood to backflow into the anterior chamber and demonstrate that Schlemm’s canal is open. 

Filling the anterior chamber with balanced saline solution shows the episcleral fluid wave.

Burk reported the 18-months results of this procedure in 120 eyes 1 year after the procedure. Half of the patients had moderate to severe

 surgery. 

The mean baseline IOP of 18.8 mm Hg decreased to 16.2 mm Hg at 18 months; 85% of patients achieved this result without the use of medications.

The results showed that 94% had an IOP of 21 mm Hg or lower, and 42% had 15 mm Hg or lower. The reduction in the overall use of medications was significant, with a saving of $84,000 in the first year, according to Burk.

IOP homeostasis in glaucoma: Looking below the surface

 used no medications, that is, 48% at 3 months and 45% at 12 months,” she said, adding that in the presence of advanced glaucoma the outflow system was thought to be irreversibly damaged. “The outflow system can be rejuvenated in advanced glaucoma.”

An advantage of the procedure under discussion is that it is repeatable, which was done in 4 eyes at 15 months after the initial procedure and then again 8 months later. Three of the patients did not require medications at 2 years.


Burk concluded that combined goniotomy and viscodilation allows access to diseased tissue by removing the trabecular meshwork and access to and viscodilation of multiple connector channels.

and has a low complication rate and fast recovery,” she said. “Cleaning the gutter and power washing the downspouts is a safe and effective way to rejuvenate the conventional outflow pathway, reduce the financial burden, and improve compliance. It’s time to rejuvenate the outflow system.” 



e: aphillips@dallaseyeandear.com
Burk has no financial interest in this subject matter.

Goniotomy-viscodilation cataract surgery controls IOP without medications.

Rejuvenation of outflow system: The time has come for procedure

This article was reviewed by J. Fernando Arevalo, MD



The new 248-gene panel provides definitive diagnoses and more personalized care for patients who previously were thought to be negative for an inherited retinal disease (IRD) using a 31-gene panel.

Gene therapy is in its infancy, and it was only in 2017 that a major clinical breakthrough became available with the launch of voretigene neparvovec-rzyl (Luxturna, Spark Therapeutics Inc), which can be used to treat IRDs caused by biallelic mutations in the 

Exploring novel gene therapy approaches to treat ocular disease

“With this therapy and other such therapies on the horizon, it is becoming increasingly important to obtain molecular diagnostics for patients with suspected IRDs,” said Mark Seraly, MD, a resident at the West Virginia University School of Medicine in Morgantown, West Virginia.

Dr. Seraly and associates conducted a retrospective chart review to determine the usefulness of the new 248-gene panel compared with the 31-gene panel for providing molecular diagnoses in 46 patients (50% men; average age, 48 years) from June 1, 2019, to October 31, 2019. 

The patients underwent next-generation sequencing with the expanded panel of 248 genes.

Blood or saliva samples were obtained during patient visits. The investigators reviewed the visual acuity, imaging results, electroretinography results, family history, and previous genetic results. 

As needed, patients were encouraged to consult a genetic counselor and arrange for variant testing, Seraly said.



Seraly reported that 13 (28.2%) of the 46 patients had positive molecular diagnoses of their IRDs; 12 (26.1%) patients were found to be carriers of pathogenic genes associated with IRDs. These 2 patient groups were urged to undergo additional genetic counseling and variant testing.

Twenty (46.5%) patients had variants of unknown significance, which means that the association between the genetic alterations and the IRDs is not fully understood, he said. Finally, only 1 (2.2%) patient in our cohort had no detected mutations.



 Intravitreal gene therapy holds promise for novel wet AMD treatment

In contrast, 18 (39.1%) patients from this cohort had undergone genetic testing 1 year prior using the 31-gene panel, and the results were negative for an IRD.

“That panel either yielded no identifiable mutations or only those of unknown significance,” Seraly said.

When the same patients underwent retesting with the 248-gene panel, the results differed substantially, with 9 (50%) of individuals gaining new clinically relevant genetic information. 

Five patients received an unequivocal molecular diagnosis and the other four were found to be carriers of single pathogenic mutations. 

The remaining 9 of 18 were all found to have additional variants of unknown significance, as compared to their prior genetic results, Seraly said.

“The new gene panel provided a wealth of information that facilitated definitive diagnoses for 5 patients with syndromic IRDs,” he said. These diseases included 2 patients with Bardet-Biedl syndrome, 2 with Usher syndrome, and 1 with Cohen syndrome.


Intravitreally injected hRPCs improve vision in retinitis pigmentosa cases

In the same cohort, 4 patients had autosomal-dominant IRDs, and 1 patient had x-linked retinitis pigmentosa. Seraly pointed out, however, that despite these diagnoses, the panel did not include analysis of the 

 gene, and some patients may have been overlooked.

Three patients in the cohort went on to familial variant testing.



A 10-year-old girl presented with frequent headaches and distorted vision, however, her visual acuity was 20/20 in both eyes. Slit-lamp examination of the anterior chambers was unremarkable. 

However, color fundus photos of both eyes showed pale-yellow lesions located inferotemporal and temporal to the macula. 

Fluorescein angiography showed that these lesions were hyperfluorescent in the late arteriovenous filling phases. Incomplete retinal vascularization was seen in the temporal peripheral retinas in both eyes.

 showed normal macular architecture in the right and left eyes; however, inner retinal folds were visibly associated with an epiretinal membrane in the right eye and an inner retinal tuft in the left eye that was associated with an epiretinal membrane and several small areas of underlying photoreceptor dropout.


Stem cells for dry AMD with GA show promise in early study

This patient underwent genetic testing and was shown to have a heterozygous mutation in the 

 gene on exon 2. Testing of the family showed 4 individuals with similar mutations in the same gene. The patient was diagnosed with autosomal-dominant familial exudative vitreoretinopathy.

“This information allowed us to tailor our follow-up with the patient in clinic and our referral for IRD resources,” Seraly said.

Based on their experience with the 248-gene panel, the investigators concluded that the expanded panel facilitates more personalized patient care—that is, genetic counseling and familial variant testing. The panel also allows refinement of searches for support groups and low-vision resources, and searches for prospective clinical trials in the future.

Seraly concluded that the current study revealed that the majority of patients were only found to harbor variants of unknown significance, indicating that more research is needed to better understand the relationship between a patient’s genotype and the phenotypic expression of their IRDs.

“In addition, in patients who received equivocal results from prior genetic testing, the 248-gene panel provided 50% of patients with new clinically relevant information about their pathogenic mutations,” he said. “More extensive panels may detect larger numbers of IRDs.”


Seraly has no financial interest in this subject matter.

Investigators reviewed visual acuity, multi-modal retinal imaging, electroretinography, family history.


Gene panel offers expanded diagnostic capability of inherited retinal diseases

The possibility of restoring sight to people blinded by age-related macular degeneration (AMD) or retinitis pigmentosa (RP) is coming closer to reality, thanks to researchers like Russell N. Van Gelder, MD, PhD, Boyd K. Bucey Memorial Chair, Professor and Chair of the Department of Ophthalmology and Director of the Roger and Angie Karalis Johnson Retina Center at University of Washington. Dr. Van Gelder was honored with the Retina Society Award of Merit in Retina Research and presented the corresponding Charles L. Schepens Lecture during the 2020 Virtual Retina Society Annual Meeting.

Dr. Van Gelder specializes in uveitis, but his research is much broader, concentrating on how ganglion cells can sense light, and using these discoveries to treat blindness. His lecture, “Prospects for Vision Restoration in Outer Retinal Degeneration,” discussed some of the most promising aspects of restoring sight to patients blinded by AMD or RP.

“I think we all find hereditary retinal degeneration among the most challenging conditions that we care for,” he said. “The concept of restoring vision to someone who's blind from retinitis pigmentosa, or from dry age-related macular degeneration, still falls into the category of miracle. We need to turn to science if we're going to have the miracle of vision restoration for these patients become a reality.”

To set the stage, Dr. Van Gelder recapped the current approaches to vision restoration including stem cell replacement, opto-electronic chips, and optogenetic gene therapy, all of which have significant barriers to implementation.

Optical electronic chips like the Argus and the Argus II chip implants, for example, have a chance of resorting central visual acuity but are implanted into the subretinal space and, therefore, are very challenging surgically. 

“[This is] an excellent potential treatment for someone with central macular degeneration or geographic atrophy. [But it is] not necessarily as effective for someone with retinitis pigmentosa, where the loss of the peripheral retinas is also contributing to their visual disability,” Dr. Van Gelder said.

He acknowledged that although gene therapy has “terrific potential,” many questions and challenges exist. “One challenge is that we still don't have great vectors at this point for ganglion cell gene therapy,” he said. “Another challenge with gene therapy is you only get one shot at it in your life.” Because gene therapy is permanent, if a patient receives an early version, they may not be able to receive a new, more effective model when one comes available.

“There are a few reasons to want to try a more reversible, small molecule approach,” Dr. Van Gelder said.

Small Molecule Photoswitches Show Promise in Animals

One of those small molecule approaches to resorting vision is the focus of Dr. Van Gelder’s work: small-molecule photoswitches. Photoswitches are pharmacologic agonists, antagonists, or channel blockers that use azobenzene, a light-isomerizable chemical moiety, to block voltage-gated potassium channels, which depolarizes neurons and causes them to fire.1 The first-generation molecule in this series is called AAQ and has been shown to restore some vision in blind mice, converting their blind retina into a photosensitive retina capable of responding to ultraviolet light.2

“The first-generation compounds had some problems,” Dr. Van Gelder said. “Ultraviolet light is not going to work in a human because our lenses will filter that out, and it's somewhat toxic. Additionally, those compounds did not turn off in the dark on their own.”

Dr. Van Gelder and his team collaborated with Richard Kramer, PhD, of UC Berkeley and Dirk Trauner, PhD, of NYU Langone Health, on a second-generation compound to address those issues. The result was compounds such as BENAQ and DENAQ, which are activated by light and turn off on their own in darkness.3 These were not without challenges, however.

“The second-generation compounds, at least the first ones, had some physiochemical problems,” Dr. Van Gelder said. “In the eye, they look like sludge. Even after 24 hours, the drug does not disperse. That sets up a concentration gradient that really is not effective in restoring vision across the entire retina.”

Together with Dr. Turner, the team developed a third-generation compound—DAD. DAD is highly soluble and specifically targets bipolar cells, but it was almost too soluble.

“We can't keep it from staining everything in sight, like the lens and the cornea,” Dr. Van Gelder said. “When we figure that problem out, I think it will be a superior compound.”

For now, the team is moving forward with BENAQ, which has good dispersion in the eye when made with a cyclodextrin excipient. It’s been tested in dogs, and does appear to work in animals.

“Our successive generation of compounds have improved the spectrum, the kinetics, the solubility, and the cell-type specificity,” Dr. Van Gelder said. “BENAQ is moving ahead into toxicology studies, so that we can hopefully get into human clinical trials in the next several years.”

1. Van Gelder RN. Photochemical approaches to vision restoration. Vision Res 2015;111(Pt B):134-41.

2. Polosukhina A, Litt J, Tochitsky I, et al. Photochemical restoration of visual responses in blind mice. Neuron 2012;75(2):271-82.

3. Tochitsky I, Polosukhina A, Degtyar VE, et al. Restoring visual function to blind mice with a photoswitch that exploits electrophysiological remodeling of retinal ganglion cells. Neuron 2014;81(4):800-13.

4.  Laprell L, Tochitsky I, Kaur K, et al. Photopharmacological control of bipolar cells restores visual function in blind mice. J Clin Invest. 2017 Jun 30;127(7):2598-2611. 

Dr. Van Gelder is an unpaid consultant to Vedere, LLC and chairs its Clinical Scientific Advisory Board; is unpaid consultant to Bayon Pharmaceuticals, which holds intellectual property on some material in this talk; and is named on a provisional patent assigned to University of Washington for some of the material discussed in the lecture.

Thanks to researchers like Russell N. Van Gelder, MD, PhD, the possibility of restoring sight to patients blinded by age-related macular degeneration or retinitis pigments is another step closer to reality. 

Schepens Lecturer Dr. Russell Van Gelder: Could small molecule photoswitches be the ‘miracle’ of vision restoration?

Ehan Rahimy, MD, speaks on the highlights of a study he presented at this year's virtual AAO 2020 meeting that aimed to integrate an artificial intelligence screening system for managing diabetic retinopathy referrals in a primary care setting — with limited specialty support.



Read and watch more AAO 2020 coverage here

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Ehan Rahimy, MD, speaks on the highlights of a study he presented at this year's virtual AAO 2020 meeting that aimed to integrate an artificial intelligence screening system for managing diabetic retinopathy referrals in a primary care setting — with limited specialty support.

Integrating AI to manage DR in a primary care setting


This article was reviewed by Delaney Curran

 (DR) Teleretinal screenings are less costly than office visits and help preserve vision. The screening can be performed in primary-care practices and may improve patient adherence to annual examinations, which historically is on the low side.

While effective in preserving vision, annual screening has the potential to increase medical costs.

Identifying biomarkers to predict diabetic retinopathy progression


This expense is magnified because the cost of treating DR has increased significantly due to the high cost of intravitreal anti-vascular endothelial growth factor anti-VEGF, which accounted for 22% of the Medicare Part B total drug spending in 2018, according to Delaney Curran, a medical student at Larner College of Medicine at the University of Vermont, Burlington. “This highlights the importance of controlling all costs of DR management,” Curran said.

In a study, Curran and colleagues wanted to determine how teleretinal screening would work in an accountable-care organization in which health providers are incentivized to follow models that improve the health of the population. She said this can be a better care experience for patients, and have lower costs.

The research study focused on three objectives: (1) determining the cost of teleretinal screening compared with an annual examination taking place in an ophthalmology office; (2) determining the direct medical costs that included those of anti-VEGF therapy for 1 year; and (3) the visual impairment outcomes at 1 year, Curran pointed out.



ASRS 2020: New imaging modalities offering bold, noninvasive, real-time monitoring of retinal diseases

According to Curran, the investigators used software (TreeAge Pro) to compare the cost-effectiveness of teleretinal screening with that of in-person screening. This decision-tree analysis attempts to model real life through probability analysis. 

In this case, the analysis would predict the endpoints of undetected retinopathy and the diagnosed and treated DR for both teleretinal screening and in-person examinations. 

The outcomes included the average incremental costs and disability weight and probability that teleretinal screening is cost-saving and more effective.

The results showed that the most likely pathway indicated that 36% of patients in each intervention type will not attend their screening and will not have DR or macular edema, Curran said.

FA implant outperforms anti-VEGF in DR patients lost-to-follow-up

The second most likely pathway indicated that 30% will undergo teleretinal screening and not have DR and 34% will undergo an in-person examination and will not have DR or macular edema.

The average annual costs per patient for teleretinal screening and in-person screening are, respectively, $230 and $292. 

On average, this amounts to a saving of $62 compared with in-person screening and a cost savings 98.4% of the time. 

Teleretinal screening resulted in a lower disability weight 55.9% of the time. The patients who underwent teleretinal screening also had a lower average cost per person when the cost of screening was less than $160, Curran said.

Based on the results of the study, teleretinal screening is a cost-saving tool and less expensive than screening during an office visit. This is likely because teleretinal screening eliminates the need for more expensive in-person examination for patients who do not have DR, who comprise the majority of the population. 


Imaging retinal pathologies can be challenging with current technologies



Anti-VEGF treatment is an expensive component of the treatment costs; however, this cost will be high regardless of the screening method. Teleretinal screening also preserves vision as effectively as in-person examinations, because of only small differences in specificity and sensitivity.

The investigators will continue with their research to determine the relative costs and vision outcomes when both interventions are available.


Curran has no financial interest in this subject matter

Process eliminates need for expensive in-person examination of patients without DR.


Teleretinal screening: Effective, less costly option for DR

Cheryl Guttman is a medical writer based in Deerfield, Ill.

This article was reviewed by Neeraj S. Chawla, BS

 power calculation formulas that take into account total corneal power measurements and the differential effect of corneal laser refractive surgery on anterior and posterior corneal curvature aim to improve refractive accuracy in eyes with a history of LASI or PRK.

However, findings from a retrospective clinical cohort study of 170 postmyopic LASIK eyes showed that, when comparing IOL power predictive accuracy, the Pentacam Scheimpflug camera-based Potvin-Hill and spectral-domain 

–based True-K formulas did not necessarily outperform other select formulas available on the American Society of Cataract and Refractive Surgery (ASCRS) IOL calculator.


Getting it right: There is no magic bullet for IOL calculations

The research was conducted by Neeraj S. Chawla, BS, a medical student at the University of Illinois at Chicago, and Navaneet S. Borisuth, MD, PhD, who is in private practice at Virdi Eye Clinic, with 3 locations in Illinois and Iowa. Chawla presented the findings at the 2020 ASCRS virtual annual meeting.

“Potential limitations of our study included a lack of complete historical LASIK data, as well as sample size,” he said. “Therefore, we believe future studies should continue to explore the Scheimpflug camera-based and OCT-based formulas using larger patient populations [and] tighter experimental conditions, as well as various subgroup analyses.”

Borisuth noted that further investigation may determine the degree and specific conditions in which these imaging-based formulas will improve patient outcomes from cataract surgery.

“The Potvin-Hill and OCT True-K formulas confer a theoretical advantage based on their advanced imaging techniques that incorporate total corneal power,” he said. “For example, the Pentacam rotating Scheimpflug camera may be specifically useful when planning for astigmatic correction in postmyopic LASIK eyes.”

Patients included in the study were operated on by Borisuth, with consideration of post-myopic LASIK eyes receiving monofocal, toric, or extended-depth of focus IOL implants. Eyes with concurrent corneal or retinal pathology were excluded from the study. 



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Postoperatively, 81.6% and 91.1% of eyes fell within ± 0.5 D and ± 1.0 D of target predicted refraction, respectively, therefore indicating “generally favorable” surgical outcomes.

IOL power formula predictive accuracy was determined using postoperative refractive data to back-calculate optimum IOL powers and absolute prediction errors.

The formulas analyzed included the Scheimpflug camera-based Potvin-Hill and spectral-domain OCT-based True-K, as well as other conventionally available formulas of the ASCRS IOL calculator. These included the Barrett True-K, Barrett True-K no-history, Masket, Modified Masket, Shammas, Haigis-L, and ASCRS Average formulas.

Mean absolute prediction error ranged from a low of 0.40 ± 0.33 D for the Barrett True-K formula to a high of 0.67 ± 0.51 D for the Shammas formula. 

Statistical analyses revealed that the Barrett True-K, ASCRS Average, and Masket formulas were significantly more accurate than the OCT True-K and Shammas formulas only. No other statistically significant differences were derived.



Haigis-TK power calculation formula provides best error prediction after LASIK

Additional subanalyses assessed directional relationships between predictive error of the imaging-based formulas with axial length and optimum IOL power. 

These analyses found that the accuracy of the Potvin-Hill formula improved with increasing axial length and decreasing optimum IOL power, whereas the OCT True-K formula was most accurate for midrange axial length and midrange optimum IOL power.

“The Potvin-Hill formula typically underpredicted optimum IOL power, [whereas] the OCT-based formula did not show directionality,” Chawla said. 



Chawla has no financial disclosures related to this content. He recently started his thirdyear medical rotations at the University of Illinois in Chicago. He graduated from Emory University in 2018 with a degree in neuroscience and behavioral biology. 


Borisuth has no financial disclosures related to this content. He is a fellow of the American Academy of Ophthalmology, the American Glaucoma Society, and the Society of Heed Fellows.

Study finds imaging-based formulas are less accurate in post-myopic LASIK eyes.

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