Natural Course for Retinal Detachment in Morning Glory Disc Anomaly Based on a Grading System

To the Editor: Morning glory disc anomaly (MGDA) is a rare congenital optic disc anomaly, characterized by an enlarged deep optic disc, radial retinal blood vessels, and peripapillary chorioretinal pigment disturbance, with a prevalence of 2.6/100,000 in children.1,2 Approximately one-third of MGDA present with retinal detachment (RD), according to a 10.3-year study.3 No standard agreement has been achieved on the necessity, time, and methods of treatment for MGDA-associated RD and large cohort study is still rare. To understand this disease better, this study was designed to describe the clinical features and natural course for MGDA-associated RD based on a grading system in a large cohort, hoping to provide some reference for treatment strategy. MATERIALS AND METHODS Between March 2011 and March 2021, the medical records of consecutive MGDA patients referred to our department were reviewed. Inclusion of subject, ophthalmic and systemic examinations, and statistical analysis followed previous studies4–6 (Supplementary Digital Content 1, https://links.lww.com/APJO/A187). MGDA-associated RD was divided into 4 grades in this study (Table 1). A worsen anatomical prognosis was herein defined as presence of a higher grade of RD or a higher grade of proliferative vitreoretinopathy (PVR) at the latest visit compared with the first (index) visit. TABLE 1 - A Grading System of MGDA-Associated RD Grade Clinical Findings A Peripapillary RD (a distance of 0–3 mm to the margin of the cavity) with (i) M-0 (i) macular noninvolved (ii) M-1 (ii) macular involved B RD in 1 or 2 quadrants (1–6 clock hours involvement) with (i) M-0 (i) macular noninvolved (ii) M-1 (ii) macular involved C RD in 3 quadrants (7–9 clock hours involvement) with (i) M-0 (i) macular noninvolved, (ii) M-1 (ii) macular involved D RD in 4 quadrants (10–12 clock hours involvement) with (i) D-1 (i) detachment shallow somewhere (ii) D-2 (ii) an open funnel shape (iii) D-3 (iii) a closed funnel shape without view of the optic disc (iv) D-4 (iv) pupil posterior synechia, pupillary atresia, severe cataract, shallow anterior chamber, or secondary glaucoma MGDA indicates morning glory disc anomaly; RD, retinal detachment. RESULTS Demographic information and chief complaints (Supplementary Digital Content 2, https://links.lww.com/APJO/A188), best-corrected visual acuity, ocular complications (Supplementary Digital Content 3, https://links.lww.com/APJO/A189), and ocular and systemic auxillary examinations (Supplementary Digital Content 4, https://links.lww.com/APJO/A190) were collected. The median age at diagnosis of the 75 patients (68 unilateral and 7 bilateral) was 46.7 months (range: 1.3–117.7 mo). At the index visit, 73% (60/82) of MGDA eyes presented with various grades of RD: grade A (21/82, 26%), grade B (4/82, 5%), grade C (15/82, 18%), and grade D (20/82, 24%) (Supplementary Digital Content 5, https://links.lww.com/APJO/A191). Macular involvement, presence of glial tissue over disc, and type of RD were listed in Supplementary Digital Content 6, https://links.lww.com/APJO/A192. PVR was found in 52 of the 60 MGDA eyes (87%) with RD, with 16 eyes exhibiting PVR grade B, 9 grade C (posterior), and 27 grade C (anterior) (Supplementary Digital Content 6, https://links.lww.com/APJO/A192). Of them, subretinal gliotic bands were present in 2 of PVR grade C (posterior) and 18 of grade C (anterior) eyes, respectively. At the latest visit, a worsen anatomical prognosis was identified in 12 of the 41 eyes (29%) followed up for over 12 months (Supplementary Digital Content 7, https://links.lww.com/APJO/A193). The median follow-up period was 32.2 months (range: 12.5–89.8 mo). There were no significant differences in the age at diagnosis, follow-up period, gender, presence of glial tissue over disc, grade of PVR, and grade of RD at the index visit between the 2 groups with stable and worsen anatomical prognosis (Supplementary Digital Content 8, https://links.lww.com/APJO/A194). DISCUSSION A higher rate of MGDA-associated RD at diagnosis was reported in this study than a previous study (73% vs 37%).3 This may be explained by the bias caused by the lower rate of regular ocular screening of children in China and our hospital being a tertiary care center treating patients with more severe ocular diseases. During a follow-up period ranging from 12.5 to 89.8 months, 12 of the 41 eyes (29%) had worsen anatomical prognosis, while over two-thirds of eyes remained stable based on the grading system. This indicated that surgery should be recommended with great caution in clinical practice. The young onset age of MGDA-associated RD should be considered before surgery and postsurgical complications should be clearly informed to legal guardians. RD in MGDA patients has been comprehensively documented in the literature.3,7,8 Combined these literature with our observations, an undocumented grading system for MGDA-associated RD was established hitherto. The grading system, applied for each patient in this cohort, required quantative assessment of the extent of RD (clock numbers). Macular involvement could cause apparent influence on patient's visual acuity. Presence of glial tissue over disc and grade of PVR were 2 predominent features of MGDA eyes. The grading system of RD combining these features could help surgeons quantitively evaluate the disease severity and developmental process. While the different prognosis for patients with the same features (PVR, type of RD, etc) implicated that primarily responsible factor was still unclear, which needs further exploration, there was a higher frequency of advanced grades of RD (grade C and D) at the index visit than that in the stable group (58% vs 33%) based on the grading system, suggesting that a higher grade of RD at diagnosis may imply increased risk of worsen prognosis. CONCLUSIONS In conclusion, about 73% of MGDA patients presented with RD in this cohort and over two-thirds of them remained stable during a follow-up period ranging from 12.5 to 89.8 months. A higher grade of RD at diagnosis may imply increased risk of worsen prognosis based on the grading system. The grading system is useful for quantitively evaluating the disease progression, which may be crucial for guiding the management.