Glaucoma management can sometimes be complex and formidable for trainees, early comprehensive practitioners and even the most seasoned specialists. We review five common scenarios from our clinical experience that may warrant prompt glaucoma referral and offer related pearls.
Overtreatment and Adverse Effects
Overtreating glaucoma occurs frequently and can lead to both ocular and systemic adverse effects. Adding a third or fourth topical medication doesn’t confer much cumulative long-term benefit in lowering intraocular pressure (IOP).
Complex eyedrop regimens also contribute to poor adherence. Depending on disease severity and stability, patients who develop ocular surface disease or other side effects from using multiple glaucoma medications might benefit from stopping one or more agents, selective laser trabeculoplasty (SLT) or incisional surgery to relieve their medication burden.
It's important to keep in mind that, unlike oral medications, glaucoma drops like beta blockers can cause serious systemic reactions since they bypass hepatic metabolism, resulting in greater plasma concentrations. Before prescribing a topical beta blocker, ask your patients if they have a history of bradycardia, obstructive airway disease exacerbation and/or systemic hypotension to avoid adverse events.
Prolonged Hypotony
Hypotony is fairly common in the immediate post-operative period following incisional glaucoma surgery. In some cases, however, hypotony can develop months or even years after traditional glaucoma surgery, for example, in the setting of a bleb leak or tube erosion. Although angle-based microinvasive glaucoma surgery (MIGS) offers an improved safety profile over trabeculectomy and tubes, inadvertent intraoperative cyclodialysis cleft creation can also result in hypotony, sometimes unbeknownst to the surgeon.
Although most cases of post-operative hypotony resolve quickly with appropriate medical therapy, potential vision-threatening sequelae sometimes develop, including corneal decompensation, anterior chamber shallowing, hypotony maculopathy, and serous or hemorrhagic choroidal effusions. Endophthalmitis resulting from an undetected bleb leak is another devastating and avoidable complication. Clinicians must therefore have a high degree of vigilance in identifying hypotony and its sequelae and referring to a glaucoma specialist in a timely manner.
Progression in the Teens
Patients with normal tension glaucoma or severe-stage glaucoma of any etiology may progress at seemingly adequate IOP in the teens. In such patients, a diurnal curve or home tonometry can help unmask IOP elevations that might otherwise go undetected during an office visit once every few months. If you detect progression in the teens via OCT RNFL or perimetry (using progression analysis software on visual fields and OCTs can help, see Figure 1 below), early glaucoma referral may be indicated. Remember the importance of repeating visual fields to confirm or refute suspected progression. Many of these patients may require incisional glaucoma surgery, often trabeculectomy, to achieve sufficiently low IOPs to stave off further disease progression.
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Trend-based analysis incorporates the patient’s entire visual field history. Visual Field Index (VFI), a global metric indicating the percentage of remaining visual field, is plotted against the patient’s age to demonstrate the rate of visual field loss. Linear regression models are used to predict future visual field loss.
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Event-based analysis compares pattern deviation values of individual test points on a new visual field to those from an average of two baseline studies. This analysis indicates the likelihood of progression based on the detection of statistically significant deterioration over a series of consecutive visual fields.
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Phaco When a Filtering Bleb or Tube Is Present
Primary tubes and trabeculectomies often hasten cataract progression, and performing cataract surgery in such eyes can present unique challenges to the anterior segment surgeon. Although a standard technique works in most cases, you may need some perioperative modifications, and they are usually best addressed by a glaucoma/cataract surgeon. Glaucoma specialists are trained to reduce the risk of intraoperative bleb injury and postoperative bleb failure, work around blebs and tubes and manage the IOP after cataract surgery.
Consultation with, or referral to, a glaucoma surgeon can help with surgical planning and optimization of post-operative outcomes.
Refractory Steroid Response or Uveitic Glaucoma
Ocular hypertension and glaucoma frequently complicate the already challenging management of patients with uveitis. Undertreating active inflammation for fear of causing or exacerbating a steroid response can lead to numerous sequelae, including peripheral anterior synechiae, posterior synechiae and macular edema.
Consider secondary causes of ocular inflammation to avoid unnecessary or overtreatment with steroids. For example, pigment dispersion syndrome (PDS) may be mistaken for uveitis since both conditions produce pigmentation of the corneal endothelium and angle. Fuchs heterochromic iridocyclitis is a uveitic entity for which treatment with long-term steroids is generally not indicated.
Uveitis-glaucoma-hyphema (UGH) syndrome should be included in the differential diagnosis of a pseudophakic patient with chronic inflammation and elevated IOP.
Finally, keep in mind the rare phenomenon of brimonidine-induced uveitis, which can present dramatically with large keratic precipitates, as are seen in other forms of granulomatous inflammation. Early glaucoma referral in these challenging scenarios can help navigate both IOP and steroid management.
The Academy’s YO Info Editorial Board is collaborating with YO leaders from our subspecialty society partners and thanks the American Glaucoma Society (AGS) junior members at large, Kateki Vinod, MD, and Angela V. Turalba, MD, for contributing this article. The AGS 2023 annual meeting will be held March 2-5 in Austin, Texas.
About the Authors
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Kateki Vinod, MD, is an associate professor of ophthalmology at the Icahn School of Medicine at Mount Sinai and the glaucoma fellowship director at New York Eye and Ear Infirmary of Mount Sinai in New York. |
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Angela V. Turalba, MD, is associate chair of visual services at Atrius Health in the Boston area. |