Electroretinography and Inherited Retinal Disease: Retinoschisis
In this third installment of Women in Visual Electrophysiology, Dr. Ding Xiaoian presented on non-invasive ERG in pediatric patients with suspected inherited retinal diseases.
Clinical manifestation and genetic analysis in Chinese early onset X-linked retinoschisis
Li Huang, Limei Sun, Zhirong Wang, Chonglin Chen, Panfeng Wang, Wenmin Sun, Xiaoling Luo, Xiaoyan Ding. Molecular Genetics and Genomic Medicine 8, 1 -12 (2020).
The aim of this study was to investigate clinical manifestation and retinoschisin 1 (RS1) mutations in Chinese patients with early-onset X-linked retinoschisis (XLRS). 38 male participants were recruited from unrelated families. Each participant had been clinically diagnosed with retinal schisis (RS) and had a pathogenic mutation in the X chromosome’s RS1 gene. The participants underwent a complete ophthalmic examination and a gene panel targeting genes associated with eye disease. The genetic testing found 30 mutations (16 previously known mutations, 14 novel mutations). The ophthalmic examination found that the clinical manifestations of XLRS vary widely and do not correlate with genotype. However, each of the 18 patients that were tested with ERG by RETeval showed similar waveforms in which the b-wave was smaller in amplitude than the a-wave. This electronegative ERG is characteristic of XLRS.
More severe complications were associated with earlier onset XLRS. Severe complications (retinal detachment and vitreous hemorrhages) presented in 21.1% of the participants, primarily in patients with onset age equal to or under 1 year old. Early onset age was also associated with higher incidence of peripheral retinoschisis, inner and outer nuclear layer splitting, non-frameshift mutations, and mutations outside the discoidin domain. This illustration of the clinical manifestations may improve the understanding of early onset XLRS. Better understanding may facilitate earlier diagnosis and help reduce vision-threatening complications.
Long-term Outcomes of Vitrectomy for Progressive X-Linked Retinoschisis
Honghua Yu, Tao Li, Yan Luo, Shanshan Yu, Shiqing Li, Lei Lei, Jiaqing Li, Xiaoyan Ding, Ling Yuan, Shibo Tang. American Journal of Ophthalmology 154 (2012)
The aim of this study was to investigate the anatomical and functional long-term outcomes of vitrectomies for patients with X-linked retinoschisis (XLRS). 28 eyes were enrolled from 22 patients with XLRS. Clinical evidence (patient symptoms, fundus changes, electroretinography, optical coherence tomography, and fluorescein fundus angiography) confirmed that each patient’s XLRS was progressive. Vitrectomies were performed on 17 eyes; no surgery was performed on 11 eyes. In the surgical group, 16 eyes (94%) achieved retinal attachment and improvement of the macular schisis cavity. Postoperative complications of the surgical group had a low incidence; 1 eye developed PVR and 1 eye had high intraocular pressure that resolved after topical treatment. The best-corrected visual acuity (BCVA) of the surgical group improved significantly from initial visit to final follow-up. By contrast, the nonsurgical group showed significantly more retinal detachment, schisis extension, and macular schisis cavity expansion, as well as worsened BCVA. Laser photocoagulation was performed on the eyes in the nonsurgical group whenever the peripheral schisis cavity threatened the macula. Despite this intervention, the retinas continued to deteriorate. Eventually, observation was terminated and vitrectomies were performed on the 10 eyes of the nonsurgical group that could withstand the operation. Retinas were successfully attached in 9 of these eyes, but only 4 eyes showed improved vision after surgery.
Progressive XLRS leads to serious complications, such as retinal detachment. Once XLRS complications have occurred, patients face a poor visual prognosis even after surgical intervention. These results show that patients who underwent vitrectomy before complications occurred had better prognoses, with improved vision and low incidence of postoperative complications. The positive anatomical and functional outcomes recommend vitrectomies for patients with progressive XLRS even at a young age. Further study is needed to fully evaluate vitrectomy as a treatment for progressive XLRS.