Lickety-Split Retina

A 19-year-old White male presented complaining of blurred vision OU at all distances. He was last seen in 2021, after which he had been referred to a retina specialist. The patient had no other significant medical history and no known family history because he was adopted.

CLINICAL FINDINGS

Examination revealed entering UCVA of 20/150 OU. At his initial examination in 2021 (Figures 1 and 2), he had no notable refractive error, with UCVA of 20/40 OU. Refraction had not been done by his retina specialist in the past few years. At the latest visit, refraction showed a significant myopic shift that restored his visual acuity back to what it was in 2021: -1.25 sph (20/40) OD and -1.50 sph (20/40) OS. The patient’s cover test, pupils, and extraocular muscles were all normal OU, and his IOPs were 18 mm Hg OD and 17 mm Hg OS.

Anterior segment examination was normal. Posterior segment examination revealed a clear vitreous OU, a cup-to-disc ratio of 0.35 OU, and no notching or hemorrhages of the optic nerve head OU. Vessels were of normal caliber OU, and there were no holes, breaks, or tears throughout the peripheral retina OU. The macula displayed diffuse elevation and distortions OU. Retinal photos were ordered (Figures 3 and 4).

CASE OUTCOME

The patient was diagnosed with X-linked juvenile retinoschisis OU, a condition that causes a bilateral, usually roughly symmetrical foveal retinoschisis starting within the first decade of life due to a mutation in the RS1 gene, of which more than 196 variations have been documented, leading to a wide variation in phenotypic expression.¹

Other differential diagnoses to consider in this case include cystoid macular edema and Goldmann-Favre syndrome, as well as a variety of other retinal dystrophies. Cystoid macular edema presents with macular thickening caused by leakage from the perifoveal capillaries and accumulation of fluid within the retinal layers.² Goldmann-Favre syndrome is an autosomal recessive retinal degeneration due to a mutation in the NR2E3 gene, causing foveal retinoschisis, nyctalopia, and retinal pigment deposits.³

This patient was fit in soft contact lenses and glasses to help restore his acuities back to 20/40 OU. He reported that attempted treatments with topical and oral carbonic anhydrase inhibitors (CAIs) by his retina specialist over the past few years were unsuccessful. He elected to continue being monitored at our clinic and was advised to return in 6 months for dilated fundus examination and to update his macular OCTs. AREDS2/lutein supplements for macular protection and blue filter use with digital devices were discussed and recommended.

DISCUSSION

There are no proven medical interventions for X-linked juvenile retinoschisis treatment; therefore, patient education about associated risks and comorbidities is crucial for disease management. Visual acuity often deteriorates most during the first and second decades of life and then remains stable until the fifth or sixth decade.⁴ Patients with X-linked juvenile retinoschisis have an increased risk for peripheral retinal thinning, retinal holes, tears, and/or fragmentation, as well as strabismus and amblyopia.⁴

Ongoing clinical trials for treatment of this condition include both topical and oral CAIs. In one study, it was found that five out of nine patients showed a significant reduction in foveal zone thickness in both eyes over a median treatment interval of 6.8 months, and visual acuity showed significant improvement in at least one eye in three out of the nine patients.⁵ The study concluded that CAIs offer long-term benefits in restoring normal retinal anatomy and may decrease the occurrence of later-onset atrophic lesions and associated visual loss; however, long-term research has yet to be conducted discussing the side effects and benefits of CAIs.

Gene therapy has demonstrated effectiveness in mouse models and is being evaluated for safety in human clinical trials.⁴ Gene therapy has shown promise in reorganizing photoreceptor-depolarizing bipolar cell synapses and restoring retinal function.⁴ In the meantime, CAIs may play a role in preserving and restoring retinal anatomy to create optimal circumstances for future gene therapy interventions in some patients.

PEDIATRIC PRIORITY

Without an updated refraction, our patient had attributed his worsening vision to his retinopathy and was pleasantly surprised to find it could be improved back to 20/40 OU with glasses and contact lenses. This case emphasizes the importance of investigating potential causes for decreased BCVA in children and offering ongoing optometric primary/refractive care alongside specialty retinal care.