Venkatesh Ramesh, Jain Kushagra, Srinivasan Priya, Pereira Arpitha, Aseem Aditya, Yadav Naresh Kumar
Department of Retina and Vitreous, Narayana Nethralaya, Bangalore, India.
Clin Exp Optom. 2020 Sep;103(5):634-640. doi: 10.1111/cxo.12966. Epub 2019 Sep 6.
Posterior microphthalmos (PM) is a rare developmental disorder characterised by high hyperopia, short axial length, presence of retinal papillomacular fold and relatively normal anterior segment findings. The study objective is to describe the retinal structural and vascular changes in eyes with PM with spectral domain optical coherence tomography, optical coherence tomography angiography and multicolour imaging.
In this retrospective, comparative case series, 10 eyes of five patients with PM as cases and 10 eyes of five age- and sex-matched controls were included. Structural changes, namely inner and outer retinal layer thicknesses, were measured using optical coherence tomography. Multicolour imaging findings were noted. Perifoveal vascular changes with qualitative and quantitative assessments were analysed using optical coherence tomography angiography.
The foveal dip was absent in all 10 eyes (100 per cent) with PM. There was an elevated retinal papillomacular fold in six eyes (60 per cent) and intraretinal cystoid spaces in two eyes (20 per cent) with PM. The inner retinal layers were thicker in PM. On multicolour imaging, foveal avascular zone and retinal wrinkles were identified in eyes with retinal papillomacular fold in blue and green reflectance images. Perifoveal vascular changes in optical coherence tomography angiography included foveal area size reduction in superficial and deep vascular networks. The foveal capillary vessel densities were higher in PM compared to the controls in both superficial (46.3 ± 3.7 per cent; p = 0.000) and deep (54.7 ± 3.5 per cent; p = 0.000) capillary plexuses. Flow areas in superficial (p = 0.693) and deep (p = 0.088) capillary plexuses were not statistically relevant.
The study suggests that in PM, retinal foreshortening occurs in one meridian leading to secondary changes such as loss of foveal dip, posterior bowing of the outer layers of the eye, thickening of the inner retina and ultimately, retinal papillomacular fold formation. The findings of the study need further validation in a larger series of patients with PM.
后部小眼球（PM）是一种罕见的发育障碍，其特征为高度远视、眼轴长度缩短、存在视网膜乳头黄斑皱褶且眼前节表现相对正常。本研究的目的是利用光谱域光学相干断层扫描、光学相干断层扫描血管造影和多色成像技术描述PM患者眼睛的视网膜结构和血管变化。
在这个回顾性、比较性病例系列研究中，纳入了5例PM患者的10只眼作为病例组，以及5例年龄和性别匹配的对照者的10只眼。使用光学相干断层扫描测量视网膜内外层厚度等结构变化。记录多色成像结果。利用光学相干断层扫描血管造影对黄斑周围血管变化进行定性和定量分析。
10只PM患眼中的所有眼（100%）均无中央凹凹陷。6只（60%）PM患眼存在视网膜乳头黄斑皱褶抬高，2只（20%）存在视网膜内囊样间隙。PM患者的视网膜内层更厚。在多色成像中，在蓝色和绿色反射图像中，有视网膜乳头黄斑皱褶的患眼中可识别出中央凹无血管区和视网膜皱褶。光学相干断层扫描血管造影显示的黄斑周围血管变化包括浅层和深层血管网络的黄斑区面积减小。与对照组相比，PM患者浅层（46.3±3.7%；p = 0.000）和深层（54.7±3.5%；p = 0.000）毛细血管丛的黄斑毛细血管密度更高。浅层（p = 0.693）和深层（p = 0.088）毛细血管丛的血流面积无统计学差异。
该研究表明，在PM中，视网膜在一个子午线方向上发生缩短，导致诸如中央凹凹陷消失、眼球外层向后弯曲、视网膜内层增厚以及最终视网膜乳头黄斑皱褶形成等继发性变化。本研究结果需要在更大系列的PM患者中进一步验证。
