Published in Glaucoma

The Role of Nitric Oxide in Glaucoma Treatment

Justin Schweitzer, OD

Justin Schweitzer, OD

Jeff Banas, OD

Jeff Banas, OD

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Join Justin Schweitzer, OD, FAAO, and Jeff Banas, OD, to review how optometrists can use nitric oxide to manage normal-tension glaucoma.

Welcome back to Pressure Points Glaucoma! In this episode, Justin Schweitzer, OD, FAAO, is joined by Jeff Banas, OD, to review a case of a patient with normal-tension glaucoma (NTG).
Dr. Banas is a practicing optometrist at The Eye Centers of Racine and Kenosha in southeastern Wisconsin, with a primary focus on glaucoma, anterior segment, and corneal refractive surgery.

Case report

A 65-year-old Caucasian female patient was referred to the clinic for a second opinion on possible glaucoma. She stated that she had never had high eye pressure and didn’t understand how she could have glaucoma.
Ocular history:
  • Past ocular history (POHX): Cataract extraction OU 2014, YAG capsulotomy OU 2014
  • Family history (FHX): Mother had been diagnosed with glaucoma and age-related macular degeneration (AMD)
  • Previous treatment regimen: None
  • Current treatment regimen: None
  • IOP Max: 17mmHg OD, 17mmHg OS
Medical history:
  • Past medical history (PMHX): Hyperlipidemia
  • All medications: Fluoxetine
  • Allergies: Penicillin
  • Blood pressure: 118/75
Ocular exam:
  • Uncorrected visual acuity (UCVA): 20/20 OD, 20/20 OS
  • External exam: Normal appearance, symmetrical
  • Pupil exam: Equal, round, reactive to light, and negative for afferent pupillary defect (APD)
  • Slit lamp exam:
    • Lens: Well-centered posterior chamber intraocular lens (IOL), open posterior capsule OU
  • Goldmann applanation tonometry: 16mmHg OD, 17mmHg OS
  • Central corneal thickness (CCT): 499 OD, 504 OS
  • Gonioscopy: Open to the ciliary body (CB) in all quadrants, no pigment in the trabecular meshwork (TM), and normal iris approach
  • Corneal hysteresis (CH): 9.4 OD, 9.3 OS
Dr. Schweitzer explained that most of the findings from the ocular exam were not remarkable for glaucoma, though at 9.3 and 9.4, the CH was borderline for risk of progression and/or conversion to glaucoma.1
Figures 1 and 2: Infrared (IR) fundus imaging OD and OS, respectively, highlighting some cup-to-disc asymmetry (0.70/0.70 OD vs. 0.50/0.50 OS) and no presence of disc hemorrhage OU.
NTG Fundus OD
Figure 1: Courtesy of Justin Schweitzer, OD, FAAO.
NTG Fundus OS
Figure 2: Courtesy of Justin Schweitzer, OD, FAAO.
Figures 3 and 4: Retinal nerve fiber layer (RNFL) thickness and visual field (VF) testing OD; they show temporal RNFL thinning and a nasal step and paracentral/ganglion cell complex (GCC) defects, respectively.
RNFL imaging OD
Figure 3: Courtesy of Justin Schweitzer, OD, FAAO.
Visual field testing OD
Figure 4: Courtesy of Justin Schweitzer, OD, FAAO.
Figures 5 and 6: RNFL thickness and VF testing OS showing temporal RNFL thinning and a notably clean VF, respectively.
RNFL testing OS
Figure 5: Courtesy of Justin Schweitzer, OD, FAAO.
Visual field testing OS
Figure 6: Courtesy of Justin Schweitzer, OD, FAAO.

Initial reflections on the case

Dr. Banas’ key takeaways from the case:
  • The patient had normal vision and IOP levels, though the CCT was somewhat lower than normal (499 OD, 504 OS), which has been associated with an increased risk of glaucoma.2
  • There was significant VF loss OD and glaucoma suspected OS; the central field loss OD was very concerning.
  • The CH was borderline but less than 10, which increases the risk of glaucomatous progression over time.1
  • The patient had significant RNFL loss OD, GCC damage OD, and early signs of GCC damage OS.
Taking all of the exam findings into account, Dr. Banas noted that he would diagnose this patient with normal-tension glaucoma (NTG), more specifically, severe NTG OD and mild NTG OS.
He added that managing NTG can present unique challenges as optimal treatments for NTG patients may vary from those with ocular hypertension (OHT) or severe primary open-angle glaucoma (POAG). In addition, it is easier to lower IOP from 25 to 18mmHg, for instance, compared to reducing it from 17mmHg to the low teens.

Treatment approaches for this glaucoma patient

For a patient with NTG, Dr. Banas explained that the primary treatment objectives should emphasize:
  1. Lowering IOP
    1. Reduce IOP from 17mmHg to 11 to 13mmHg
  2. Improving perfusion to the optic nerve
    1. Increasing blood flow permeability and transmissibility to the optic nerve gives the patient the best chance for long-term treatment success by stabilizing and arresting the disease state
  3. Identifying a well-tolerated therapy with a treatment regimen that the patient will likely adhere to
    1. Dr. Banas noted that if he chooses a therapy that the patient does not like, adherence will decrease, and the patient’s vision will likely suffer as well.
Dr. Banas noted that selective laser trabeculoplasty (SLT) would likely not be an optimal intervention for this patient (particularly as a standalone treatment), as it does not address the reduced optic nerve blood flow.3 In addition, due to the patient’s age, Dr. Banas mentioned that he would prefer to take an aggressive treatment approach. As such, he would likely first prescribe a nitric oxide (NO)-donating prostaglandin analog (PGA) like latanoprostene bunod (LBN).
LBN has a dual mechanism of action in which latanoprost reduces IOP by increasing uveoscleral outflow via long-term remodeling of the extracellular matrices in the ciliary body (i.e., non-conventional outflow), while NO donors induce relaxation of the trabecular meshwork and Schlemm’s canal, leading to increased aqueous outflow (i.e., conventional outflow).4 Additionally, in Dr. Banas’ experience, patients tend to tolerate LBN very well as a first-line therapy.

Relevant research on latanoprostene bunod

To dig deeper into the efficacy of LBN Drs. Schweitzer and Banas reviewed the findings from the 2016 JUPITER Study. This investigation evaluated the long-term safety and IOP-lowering efficacy of LBN ophthalmic solution 0.024% (Vyzulta, Bausch + Lomb) over 1 year in patients with OAG (including pigmentary, pseudoexfoliative, and NTG) or OHT.4
In this multicenter, open-label clinical study, patients aged 20 years and older with a diagnosis of OAG or OHT instilled one drop of LBN ophthalmic solution in the affected eye(s) once daily in the evening for 52 weeks and were evaluated every 4 weeks. In total, 130 patients were enrolled, of which 121 participants (mean age 62.5 years) with a mean baseline IOP of 19.6mmHg in study eyes and 18.7mmHg in fellow eyes completed the study.4
Overall, 58.5% (121/130) and 61.9% (78/126) of subjects experienced ≥1 adverse event (AE) in study eyes and treated fellow eyes, respectively. In both the study eyes and treated fellow eyes, the most common AEs were conjunctival hyperemia, growth of eyelashes, eye irritation, and eye pain.4
At 52 weeks, 9% of treated eyes had an increase in iris pigmentation compared with baseline, which was assessed using iris photographs. No safety concerns emerged based on vital signs or other ocular evaluations. Of note, by week 4, mean reductions from baseline IOP of 22.0% and 19.5% were achieved in the study and treated fellow eyes, respectively. These reductions were maintained through week 52.4
Ultimately, this study demonstrated the efficacy, tolerability, and long-term effects of LBN for glaucoma patients, noted Dr. Banas.

Case conclusion

The patient was diagnosed with severe NTG OD and pre-perimetric NTG OS. Dr. Schweitzer decided to initiate latanoprostene bunod 0.024% qd at night OU with the goal of reducing IOP by 25% or more from baseline IOP.
At the 6-week follow-up visit, the patient had a pressure of ~12mmHg.
  1. Deol M, Taylor DA, Radcliffe NM. Corneal hysteresis and its relevance to glaucoma. Curr Opin Ophthalmol. 2015;26(2):96-102. doi:10.1097/ICU.0000000000000130
  2. Belovay GW, Goldberg I. The thick and thin of the central cornea thickness in glaucoma. Eye (Lond). 2018;32(5):915-923. doi:10.1038/s41433-018-0033-3
  3. Hillman L. Current perspectives on NTG and progression at low IOPs. EyeWorld. Spring 2024. Accessed February 10, 2025. https://www.eyeworld.org/2024/current-perspectives-on-ntg-and-progression-at-low-iops/.
  4. Kawase K, Vittitow JL, Weinreb RN, Araie M, JUPITER Study Group. Long-term safety and efficacy of latanoprostene bunod 0.024% in Japanese subjects with open-angle glaucoma or ocular hypertension: The JUPITER study. Adv Ther. 2016;33(9):1612-1627. doi:10.1007/s12325-016-0385-7
Justin Schweitzer, OD
About Justin Schweitzer, OD

Dr. Justin Schweitzer is a fellowship-trained optometrist specializing in the treatment of glaucoma, corneal-related vision conditions, and cataracts at Vance Thompson Vision in Sioux Falls, SD.

More by Justin Schweitzer, OD
Justin Schweitzer, OD
Jeff Banas, OD
About Jeff Banas, OD

Jeff Banas, OD, graduated from Roosevelt University in 2010, where he completed an Honors program to earn his Bachelor of Science in biology with a minor in chemistry. Dr. Banas furthered his studies by attending the Illinois College of Optometry, the United States' first and oldest optometric program, where he earned his optometric degree.

Dr. Banas completed multiple clinical rotations, including rotations at Ochsner Medical Center in New Orleans, Illinois Eye and Ear Infirmary in Chicago, and Zablocki VA Medical Center in Milwaukee. Dr. Banas is a member of the American Optometric Association, Wisconsin Optometric Association, Milwaukee Optometric Society, and NBEO certified.

Dr. Banas provides comprehensive ocular care for all ages, but specializes in ocular disease. Dr. Banas has a particular emphasis on treating ocular complications of diabetes, glaucoma, dry eye, age-related macular degeneration, cataracts, and refractive error.

More by Jeff Banas, OD
Jeff Banas, OD
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