Managing Nonproliferative Macular Telangiectasia Type 2

A 57-year-old female presented for her annual examination with a chief complaint of difficulty seeing at all distances in her current trifocal spectacle lens prescription, particularly during computer use. She reported an overall decline in her ability to perform activities of daily living due to her reduction in distance vision. Further, the patient noted she had been occasionally using handheld magnifiers for near tasks but found them insufficient in providing optimal vision.

PATIENT HISTORY

The patient’s systemic history was significant for hypercholesterolemia and hypertension. Her ocular history was positive for mild nuclear cataracts OU and asteroid hyalosis OS.

EXAM FINDINGS

On examination, BCVA was 20/40-2 OD and 20/50-2 OS. Cover test, pupillary responses, extraocular motility, anterior segment examination, and IOPs were all within normal limits. Posterior segment examination revealed focal hyperpigmentation and pigment migration in the macula OU (Figures 1 and 2), central scotomas OU (Figure 3), and disruption of the ellipsoid zone, and a photoreceptor layer with significant pigment migration OU (Figure 4).

DIAGNOSIS

The diagnosis of nonproliferative macular telangiectasia type 2 was established based on characteristic macular findings, including focal hyperpigmentation and pigment migration, and was supported by OCT findings, which demonstrated disruption of the ellipsoid zone and photoreceptor layers. These structural abnormalities were consistent with the patient’s degree of visual impairment and symptomatic central scotomas.

Macular telangiectasia is characterized by abnormalities of the capillaries in the foveal or perifoveal region and associated with loss of the outer nuclear layer and disruption of the ellipsoid zone, resulting in progressive vision loss.^1,2 The disease may progress to a proliferative phase, involving subretinal neovascularization.

Macular telangiectasia type 2 is the most common form of macular telangiectasia and is increasingly understood to be a neurodegenerative process involving Müller cell dysfunction, which leads to loss of retinal neurons.³ The condition is usually bilateral, though often asymmetric in severity, and is frequently diagnosed in patients between 40 and 60 years of age. Visual prognosis can range from 20/20 to 20/200, depending on disease stage.³ Worse visual outcomes are associated with greater levels of photoreceptor loss, which typically correlates with findings of more extensive retinal pigment epithelium hyperplasia.¹

MANAGEMENT

To optimize the patient’s functional vision, we discussed the use of a presbyopia drop and AI glasses. Also, the patient was referred for a revakinagene taroretcel-lwey (Encelto, Neurotech Pharmaceuticals) consultation with a retina specialist.

Presbyopia drops cause pupil miosis, which may reduce visual distortion, improve clarity, and enhance overall visual function at near ranges. These characteristics may allow these patients to gain 1 or more lines of visual acuity during near tasks. We were hopeful that these drops would most benefit our patient during computer use, as she says she finds that range to be the most difficult. These drops work best for presbyopic patients who have minimal distance prescriptions. Our patient was a low hyperopic astigmat with a distance prescription of +0.50-1.25x090 OD and +0.25-1.00x085 OS, with an ADD of +2.75. Potential side effects, including instillation discomfort, ocular redness, transient visual dimming, and headaches/brow aches, were reviewed with the patient. The importance of regular retinal examinations during treatment was also discussed.

AI glasses have small cameras and speakers built into them, along with a voice assistant that can answer questions. This technology can assist with daily activities, such as reading labels while shopping and identifying medication bottles. These glasses are becoming more widely available. This patient did need a basic level of technological literacy to use them effectively.

Encelto is a new FDA-approved implantable medication that uses encapsulated cell technology to slow the progression of macular telangiectasia type 2. It measures about 6.5 mm and is inserted into the vitreous cavity where it is anchored to the sclera to provide continuous intraocular release of ciliary neurotrophic factor. this is a neuroprotective protein that helps prevent photoreceptor death, thus slowing visual function loss.^4-6 Encelto potentially preserves visual function in macular telangiectasia patients prior to them progressing to neovascularization.

Anti-VEGF therapy has been effective at controlling possible subretinal neovascularization that may arise in later stages of macular telangiectasia.³

FOLLOW-UP

The patient will return in 6 months for a follow-up visit that includes repeat macular OCT, fundus photography, fundus autofluorescence, and an updated 10-2 visual field for continued assessment of functional vision and disease progression.²

KEEP UP, NOT CATCH UP

Ongoing monitoring of nonproliferative macular telangiectasia type 2 patients through employing regular fundus examinations and OCT is essential for assessing disease progression and detecting the development of neovascular complications. Equally important is optimizing patients’ remaining functional vision through appropriate supportive measures.