Morphological differences between two types of Bruch's membrane defects in pathologic myopia

Comparison of visual acuity outcome and choroidal thickness variation of intravitreal ranibizumab injection for myopic choroidal neovascularization with or without dome-shaped macula

BACKGROUND

To investigate the visual acuity outcome and choroid thickness (CT) change after intravitreal ranibizumab in highly myopic eyes with or without dome-shaped macula (DSM) in Chinese patients.

METHODS

This retrospective, observative study included 80 treatment-naive eyes (80 patients), which received ranibizumab according to the 1+PRN protocol. The best corrective visual acuity (BCVA) and CT change were compared between eyes with or without DSM.

RESULTS

There was no significant difference between eyes with or without DSM in BCVA and central macular thickness (CMT). The recurrent rate was not different between the two groups during the first year of treatment. The CT was significantly thinner in eyes with DSM than in eyes without DSM before treatment (median 40.00um versus 71.00um), at 1 month after treatment (median 31.00um versus 65.50um), and in the last follow up (median, 32.00um versus 65.00um) (p = 0.0101). Axial length (AL) was longer in eyes with DSM than those without DSM (median, 29.17 mm versus 28.10 mm) before treatment, and in the last follow up (median, 29.44 mm versus 28.20 mm) (p = 0.0055). The CT was significantly correlated with AL (p < 0.0001).

CONCLUSIONS

No difference was found in visual outcome between eyes with or without DSM. The visual acuity significantly improved at 1 month after ranibizumab injection and it was recovery sooner in extrafoveal choroidal neovascularization (CNV) group than in subfoveal CNV group. The CT was thinner in eyes with DSM, which was significantly correlated with AL.

Myopia: Histology, clinical features, and potential implications for the etiology of axial elongation

Myopic axial elongation is associated with various non-pathological changes. These include a decrease in photoreceptor cell and retinal pigment epithelium (RPE) cell density and retinal layer thickness, mainly in the retro-equatorial to equatorial regions; choroidal and scleral thinning pronounced at the posterior pole and least marked at the ora serrata; and a shift in Bruch's membrane opening (BMO) occurring in moderately myopic eyes and typically in the temporal/inferior direction. The BMO shift leads to an overhang of Bruch's membrane (BM) into the nasal intrapapillary compartment and BM absence in the temporal region (i.e., parapapillary gamma zone), optic disc ovalization due to shortening of the ophthalmoscopically visible horizontal disc diameter, fovea-optic disc distance elongation, reduction in angle kappa, and straightening/stretching of the papillomacular retinal blood vessels and retinal nerve fibers. Highly myopic eyes additionally show an enlargement of all layers of the optic nerve canal, elongation and thinning of the lamina cribrosa, peripapillary scleral flange (i.e., parapapillary delta zone) and peripapillary choroidal border tissue, and development of circular parapapillary beta, gamma, and delta zone. Pathological features of high myopia include development of macular linear RPE defects (lacquer cracks), which widen to round RPE defects (patchy atrophies) with central BM defects, macular neovascularization, myopic macular retinoschisis, and glaucomatous/glaucoma-like and non-glaucomatous optic neuropathy. BM thickness is unrelated to axial length. Including the change in eye shape from a sphere in emmetropia to a prolate (rotational) ellipsoid in myopia, the features may be explained by a primary BM enlargement in the retro-equatorial/equatorial region leading to axial elongation.

Clinical Characterization of Autosomal Dominant and Autosomal Recessive PROM1 Mutation With a Report of Novel Mutation

BACKGROUND AND OBJECTIVE

This study aims to provide clinical characterization of PROM1 mutation with a report of novel mutation.

PATIENTS AND METHODS

This study is a retrospective case series of six patients from a single institution with multimodal imaging, electroretinography, and genetic testing.

RESULTS

Six patients aged 12 to 47 years were identified. Patients with autosomal recessive (AR) variants showed more severe panretinal dystrophy with symmetrical macular involvement and peripheral retinal pigment epithelium atrophy. The autosomal dominant (AD) variants, on the other hand, showed milder macular involvement with bull's eye maculopathy phenotype with minimal peripheral involvement. Among patients with AR variants, a younger patient with aberrant splicing showed a milder phenotype compared with patients with a nonsense mutation and an additional ABCA4 mutation.

CONCLUSION

The authors describe patients with PROM1 retinopathy inherited AD and AR inherited patterns. Novel mutations of c.1909C>T and c.2050C>T were identified, leading to truncation of the protein at sequence p.Gln637* and p.Arg684*, respectively. [Ophthalmic Surg Lasers Imaging Retina 2022;53:422-428.].