Paravascular inner retinal abnormalities in healthy eyes

EVALUATION OF PARAVASCULAR INNER RETINAL DEFECTS USING EN FACE OPTICAL COHERENCE TOMOGRAPHY

PURPOSE

To evaluate the prevalence and risk factors for development of paravascular inner retinal defects (PIRDs) using en face optical coherence tomography.

METHODS

This is a retrospective cross-sectional study. En face and cross-sectional optical coherence tomography images were reviewed (9 × 9 mm or 12 × 12 mm). Paravascular inner retinal defects were classified as either Grade 1 (i.e., paravascular inner retinal cysts) when the lesion was confined within the nerve fiber layer without any communication to the vitreous cavity or Grade 2 (i.e., paravascular lamellar hole) when the defects communicated to the vitreous. Paravascular inner retinal defect grading was correlated with presence of high myopia, stage of posterior vitreous detachment, and presence of epiretinal membrane and retinoschisis.

RESULTS

Of 1,074 patients (2,148 eyes), PIRDs were detected in 261 eyes with a prevalence of 261 per 2,148 eyes (12.2%) and 176 per 1,074 patients (16.4%). A total of 116 eyes (44.4%) displayed Grade 2 PIRDs while 145 eyes (55.6%) were Grade 1. In the multivariate logistic regression model, the presence of partial/complete posterior vitreous detachment, retinoschisis, and epiretinal membrane was significantly correlated with PIRDs (OR = 2.78 [1.7-4.4], P < 0.001; OR = 2.93 [1.7-5], P < 0.001; and OR = 25.9 [2.8-242.5], P < 0.001, respectively). The presence of partial/complete posterior vitreous detachment and epiretinal membrane was also significantly associated with Grade 2 PIRDs versus Grade 1 PIRDs ( P = 0.03 and P < 0.001).

CONCLUSION

Our results indicate that wide-field en face optical coherence tomography facilitates the identification of PIRDs over a large area of retina with a single capture. The presence of PIRDs was significantly associated with posterior vitreous detachment, epiretinal membrane, and retinoschisis, confirming the role of vitreoretinal traction in the pathogenesis of PIRDs.

Swept-Source OCT En Face Imaging of Paravascular Inner Retinal Defects

Widefield swept-source optical coherence tomography angiography (SS-OCTA) was performed on eyes with paravascular inner retinal defects (PIRDs) and the morphological alterations of PIRDs were described. Patients with PIRDs were imaged using 12 mm × 12 mm SS-OCTA scans. En face structural and angiographic images of the superficial retinal layers were reviewed along with retinal thickness maps. SS-OCTA en face structural images identified dark, scalloped regions along major retinal veins that corresponded to PIRDs on B-scans. The authors concluded that imaging with both structural and angiographic en face OCT was useful for the diagnosis and monitoring of patients with PIRDs. [Ophthalmic Surg Lasers Imaging Retina. 2021;52:407-411.].

Posterior segment conditions associated with myopia and high myopia

Myopia, and especially high myopia, is associated with a number of posterior segment changes that are considered to be mostly a consequence of the increased axial elongation. This can result in mechanical strain, attendant vascular changes, stretching and thinning of tissues, and atrophy/deformation of tissues in later or more advanced stages. Such myopia-related changes are observed as changes and/or abnormalities in the vitreous, choroid, retina and peripheral retina, sclera and/or optic disc. Although many of these changes are benign, at times they may be associated with significant vision impairment that either requires active intervention or may suggest future progression of the disease. This review systematically addresses the posterior segment conditions seen in myopic eyes, describes the features associated with the condition and details management pathways.

Spectral-domain optical coherence tomography of retinal vessels in Waldenström's macroglobulinemia

PURPOSE

To image retinal blood vessels in patients with Waldenström's macroglobulinemia using optical coherence tomography (OCT).

METHODS

Retrospective case series examining fundus photographs and OCT scans of 16 eyes in eight patients with Waldenström's macroglobulinemia. Analyses included intravascular OCT reflectivity profiles and vessel diameters, and their relation to total immunoglobulin M (IgM) levels.

RESULTS

In six out of eight patients, cross-sectional OCT scans of larger retinal vessels (diameter > 100 μm) showed normal intravascular reflectivity and retrovascular shadowing. In two patients with the highest total IgM > 60 g/l, altered intravascular reflectivity, distinct anterior and posterior vessel wall reflexes, and retrovascular hyposhadowing were seen. Normalization of the OCT reflectivity in these patients occurred after reduction of total IgM to < 17 g/l and was accompanied by decreasing venous tortuosity and disappearance of retinal haemorrhages and cotton wool spots.

CONCLUSION

This study found that Waldenström's macroglobulinemia and total IgM > 60 g/l were associated with abnormal intravascular reflectivity and retrovascular shadowing on OCT. Awareness of these signs of hyperviscosity could potentially enable earlier detection of critical conditions in patients with Waldenström's macroglobulinemia and improve the assessment of severity and treatment effect.

An Examination of the Frequency of Paravascular Defects and Epiretinal Membranes in Eyes With Early Glaucoma Using En-face Slab OCT Images

PURPOSE

To examine the frequency of paravascular defects (PDs) and macular epiretinal membranes (ERMs) in eyes categorized as having mild glaucoma or glaucoma suspect using en-face slab analysis of optical coherence tomography (OCT) scans.

MATERIALS AND METHODS

Fifty-seven glaucomatous eyes, 44 low-risk suspect eyes, and 101 healthy control eyes were included in the study. The 101 glaucomatous and suspect eyes had a mean deviation better than -6 dB on the 24-2 visual field, and a spherical refractive error between±6 D or axial length <26.5 mm. Two OCT-graders masked to eye classification identified ERMs and PDs on en-face slab images of the macula and peripapillary retina using horizontal B-scans and derived vertical B-scans.

RESULTS

Glaucomatous eyes had a significantly higher number of PDs and ERMs than healthy controls (PD, P<0.001; ERM, P=0.046) and low-risk glaucoma suspects (PD, P=0.004; ERM, P=0.043). PDs and/or ERMs were present in 16 of 57 (28.1%) glaucomatous eyes, 2 of 44 (4.5%) suspect eyes, and 3 of 101 (3.0%) control eyes. Further, PDs were present in 11 of the 57 (19.3%) glaucomatous eyes, 1 of the 44 (2.3%) suspect eyes and 0 of the 101 (0%) control eyes, ERMs were seen in 7 of the 57 (12.3%) glaucomatous eyes, 1 of the 44 (2.3%) suspects, and 3 of the 101 (3.0%) control eyes.

CONCLUSIONS

Eyes with early glaucoma have a higher frequency of PDs and ERMs than suspects or controls and exhibit PDs even in the absence of ERMs or high myopia.

Long-term follow-up of retinal nerve fiber layer cleavages in glaucoma patients and suspects

PURPOSE

To investigate the structural and functional characteristics and change of the retinal nerve fiber layer cleavages (RNFLCs) in glaucoma patients and suspects in long-term follow-up.

METHODS

This is a retrospective longitudinal study. Within 43 eyes of 30 subjects, 62 RNFLC locations were detected on color fundus photography. Basic ophthalmic examinations, color fundus photography, optical coherence tomography (OCT), and visual field (VF) test were performed in 6-month intervals. Clinical characteristics and the structural and functional changes of the cleaved areas were analyzed.

RESULTS

RNFLC and localized vitreoretinal traction occurred most commonly along the superotemporal retinal vessel arcade. Nine locations had corresponding defects on OCT deviation map, while 31 locations were associated with defects on OCT deviation map. Three locations had corresponding VF defects. More of the non-highly myopic eyes had lamellar hole than the highly myopes (p = 0.038). The RNFLC lesions in glaucomatous eyes were more frequently associated with OCT defects on deviation map (p = 0.021). There was no difference in the presence of lamellar hole or the number of RNFLCs between the glaucomatous and non-glaucomatous eyes. During a 66.8 ± 37.8-month follow-up, there was no structural or functional progression of the RNFLCs as determined by color fundus photography, VF test, and GPA of OCT interpreted by three ophthalmologists. There was no statistically significant change of RNFLC area (p = 0.268).

CONCLUSIONS

RNFLC did not show detectable functional or structural change in early glaucoma patients and suspects after long-term follow-up.