Changes in conjunctival–scleral thickness after strabismus surgery measured with anterior segment optical coherence tomography

Purpose

To evaluate changes in conjunctival–scleral thickness following strabismus surgery with anterior segment optical coherence tomography (AS-OCT).

Study Design

Prospective, observational, consecutive case series.

Methods

Distances between the conjunctival epithelium and inner scleral wall were measured with AS-OCT before and 3–5 months after strabismus surgery. The measurements were performed at 1.5 mm (limbus), 7.0 mm (insertion), and 8.0 mm (tendon) posterior to the scleral spur on the lateral rectus muscle (LR); and 1.5 mm (limbus), 4.0 mm (insertion), and 5.5 mm (tendon) posterior to the scleral spur on the medial rectus muscle (MR). Thirty-three extraocular muscles (20 LRs and 13 MRs) from 23 subjects were studied.

Results

Thicknesses were significantly less at the insertion (0.95–0.78 mm; p?<?0.001) and tendon (0.99–0.78 mm; p?<?0.001) after LR recession and at the tendon (1.21–0.92 mm; p?=?0.02) after MR recession. Thicknesses were significantly greater at the insertion (0.82–1.07 mm; p?=?0.01) and tendon (0.95–1.28 mm; p?=?0.01) after MR resection or plication and at the limbus, insertion, and tendon (0.75–0.90 mm, 0.94–1.19 mm, 1.03–1.28 mm, respectively; all p?=?0.04) after LR resection or plication.

Conclusion

Conjunctival–scleral thicknesses showed various changes after recession and resection or plication. These findings may help detect previous surgical operations when conjunctival scarring and ciliary vessel changes are unclear.

     

Retinal capillary plexus in Parkinson’s disease using optical coherence tomography angiography

AIM: To evaluate the alterations of the retinal microvasculature and foveal avascular zone in patients with Parkinson’s disease (PD) using optical coherence tomography angiography (OCT-A). METHODS: A retrospective study of PD patients examined in the Ophthalmology Department of the General Hospital of Athens, “Georgios Gennimatas” from March 2021 to March 2022 was conducted. Totally 44 patients with PD were included and 18 healthy controls were examined, hence a total of 124 eyes were enrolled in the study. The foveal and parafoveal superficial and deep capillary plexus vascular density (fSCP-VD, fDCP-VD, pSCP-VD, pDCP-CD) and foveal avascular zone (FAZ) were quantified with OCTA. Optical coherence tomography (OCT) was used to measure macular thickness. Our statistical analysis was conducted by using a mixed effect linear regression model. RESULTS: After adjustment for age and gender, the mean parafoveal superficial capillary plexus vascular density (pSCP-VD) and mean parafoveal deep capillary plexus vascular density (pDCP-VD) were significantly decreased in individuals with PD (P<0.001 in both) by -2.35 (95%CI -3.3, -1.45) and -7.5 (95%CI -10.4, -4.6) respectively. fSCP-VD and fDCP-VD didn’t approach statistical significance. The FAZ area and perimeter were significantly decreased (P<0.001 in both) by -0.1 mm2 (95%CI -0.13, -0.07) and -0.49 mm2 (95%CI -0.66, -0.32) respectively. Circularity didn’t approach statistical significance. Central retinal thickness (CRT) was significantly decreased in individuals with PD (P<0.001) by -23.1 μm (95%CI -30.2, -16) and temporal retinal thickness (TRT) was decreased (P=0.025) by -11 μm (95%CI -22, -1.5) while nasal retinal thickness (NRT) only approached statistical significance (P=0.066). CONCLUSION: The mean pSCP-VD, pDCP-VD, CRT and TRT are significantly decreased and FAZ is altered in individuals with PD. These findings can be potentially used as biomarkers for the diagnosis and evaluation of early PD.     

Evaluation of retinal microvascular structures by optical coherence tomography angiography in primary Sjögren’s syndrome

International Ophthalmology - There are insufficient data in the literature on how retinal capillaries are affected in primary Sjögren's syndrome (PSS). The aim of this study was to...     

Altered microvascular density in patients with systemic lupus erythematosus treated with hydroxychloroquine—an optical coherence tomography angiography study

Graefe's Archive for Clinical and Experimental Ophthalmology - To evaluate the retinal microvascular density using optical coherence tomography angiography (OCTA) in patients with systemic...     

Deep lateral wall orbital decompression following strabismus surgery in patients with Type II ophthalmic Graves’ disease

Purpose: Surgical management of ophthalmic Graves’ disease traditionally involves, in order, orbital decompression, followed by strabismus surgery and eyelid surgery. Nunery et al. previously described two distinct sub-types of patients with ophthalmic Graves’ disease; Type I patients exhibit no restrictive myopathy (no diplopia) as opposed to Type II patients who do exhibit restrictive myopathy (diplopia) and are far more likely to develop new-onset worsening diplopia following medial wall and floor decompression. Strabismus surgery involving extra-ocular muscle recession has, in turn, been shown to potentially worsen proptosis. Our experience with Type II patients who have already undergone medial wall and floor decompression and strabismus surgery found, when additional decompression is necessary, deep lateral wall decompression (DLWD) appears to have a low rate of post-operative primary-gaze diplopia.

Methods: A case series of four Type II ophthalmic Graves’ disease patients, all of whom had already undergone decompression and strabismus surgery, and went on to develop worsening proptosis or optic nerve compression necessitating further decompression thereafter. In all cases, patients were treated with DLWD. Institutional Review Board approval was granted by the University of Kansas.

Results: None of the four patients treated with this approach developed recurrent primary-gaze diplopia or required strabismus surgery following DLWD.

Conclusions: While we still prefer to perform medial wall and floor decompression as the initial treatment for ophthalmic Graves’ disease, for proptosis following consecutive strabismus surgery, DLWD appears to be effective with a low rate of recurrent primary-gaze diplopia.     

Evaluation of retinal and choroidal changes in patients with Alzheimer’s type dementia using optical coherence tomography angiography

AIM: To evaluate the changes in fundus parameters in patients with Alzheimer’s type dementia (ATD) using optical coherence tomography angiography (OCTA), to record flash electroretinograms (ERG) using the RETeval system and to explore changes in retinal function. METHODS: Twenty-nine patients with ATD and 26 age-matched normal subjects were enrolled. All subjects underwent OCTA scans to analyse the superficial retinal vessel parameters in the macular area, including the vessel length density, the vessel perfusion density and the area of foveal avascular zone (FAZ), as well as the choroidal thickness. The differences between the patients with ATD and the normal control group were compared and explored the relevant factors affecting vessel parameters. We also recorded the flash ERGs using the RETeval system and intended to explore changes in retinal function by analysing the ERG image amplitude in patients with ATD. RESULTS: The vessel parameters [Pvessel length density=0.005 and Pvessel perfusion density=0.006) and average choroid thickness (P<0.001) in the macular area of the ATD group was less than the control group. The FAZ area was statistically significantly enlarged in the ATD group (P<0.001). These parameters were correlated with the Mini-Mental State Examination (MMSE) score and the Montreal Cognitive Assessment (MoCA). CONCLUSION: Patients with ATD exhibit decreases in the parameters associated with fundus. In addition, these indicators significantly correlate with the MMSE score and the MoCA score. OCTA may be an adjunct tool with strong potential to track changes in the diagnosis and monitoring the progression of the disease.     

Structural-visual functional relationships detected by optical coherence tomography in varying age-cohorts’ patients with optic neuritis

AIM: To assess the relationships of final best-corrected visual acuity (BCVA) and the optic nerve structural loss in varying age-cohorts of optic neuritis (ON) patients.METHODS: This is a retrospective, cross-sectional study. Totally 130 ON subjects (200 eyes) without ON onset within 6mo were included, who underwent BCVA assessment, peripapillary retinal nerve fibre layer (pRNFL) and macular segmented layers evaluation by optical coherence tomography (OCT).RESULTS: For the 0-18y cohort, the final BCVA (logMAR) was significantly better and less frequent recurrences than adult cohorts (P=0.000). The final BCVA (logMAR) in all age-cohorts of the ON patients had negative and linear correlations to the pRNFL thicknesses and macular retinal ganglion cell layer (mRGCL) volumes, when the pRNFL thicknesses were reduced to the thresholds of 57.2-67.5 µm or 0.691-0.737 mm3 in mRGCL volumes, respectively, with the strongest interdependence in the 19-40y cohort. The ON patients from varying age cohorts would be threatened by blindness when their pRNFL thicknesses dropped 36.7-48.3 µm or the mRGCL volumes dropped to 0.495-0.613 mm3.CONCLUSION: The paediatric ON has best prognosis and young adult ON exhibits perfectly linear correlations of final vision and structural loss. The pRNFL and the mRGCL could be potential structural markers to predict the vision prognosis for varying-age ON patients.     

Characteristics of treatment-naïve quiescent choroidal neovascularization detected by optical coherence tomography angiography in patients with age-related macular degeneration

Graefe's Archive for Clinical and Experimental Ophthalmology - To determine the characteristics of eyes with treatment-naïve quiescent choroidal neovascularization (CNV) detected by...     

[Online First]Evaluation of retinal and choroidal changes in patients with Alzheimer’s type dementia using optical coherence tomography angiography

AIM: To evaluate the changes in fundus parameters in patients with Alzheimer’s type dementia (ATD) using optical coherence tomography angiography (OCTA), to record flash electroretinograms (ERG) using the RETeval system and to explore changes in retinal function. METHODS: Twenty-nine patients with ATD and 26 age-matched normal subjects were enrolled. All subjects underwent OCTA scans to analyse the superficial retinal vessel parameters in the macular area, including the vessel length density, the vessel perfusion density and the area of foveal avascular zone (FAZ), as well as the choroidal thickness. The differences between the patients with ATD and the normal control group were compared and explored the relevant factors affecting vessel parameters. We also recorded the flash ERGs using the RETeval system and intended to explore changes in retinal function by analysing the ERG image amplitude in patients with ATD. RESULTS: The vessel parameters [Pvessel length density=0.005 and Pvessel perfusion density=0.006) and average choroid thickness (P<0.001) in the macular area of the ATD group was less than the control group, The FAZ area was statistically significantly enlarged in the ATD group (P<0.001). These parameters were correlated with the Mini-Mental State Examination (MMSE) score and the Montreal Cognitive Assessment (MoCA). CONCLUSION: Patients with ATD exhibit decreases in the parameters associated with fundus. In addition, these indicators significantly correlated with the MMSE score and the MoCA score. OCTA may be an adjunct tool with strong potential to track changes in the diagnosis and monitoring the progression of the disease.     

Calibration of histological retina specimens after fixation in Margo’s solution and paraffin embedding to in-vivo dimensions, using photography and optical coherence tomography

Background

The extent of retinal tissue deformation by histological processing needs to be separately measured for every workup protocol. This work presents a simple approach for its quantitative assessment, and shows lateral and axial scaling factors for a common protocol. We calibrated histological measurements by in-vivo photographic and optical coherence tomographic (OCT) measurements, using retinal photocoagulation lesions as calibration markers.

Methods

We evaluated four rabbit eyes that were examined histologically after fixation in Margo’s solution (1 % paraformaldehyde:1.25 % glutaraldehyde), isopropanol dehydration, paraffin embedding and hematoxylin and eosin staining. Distances between 51 pairs of laser lesions were compared in photographs and on histological slides. Retinal thickness measurements were performed at 15 anatomically defined sites in these eyes, and related to anatomically matched OCT thickness measurements of six different rabbit eyes.

Results

We found that the ratio of histological over photographic lesion distances was 1.17 (95 % CI 1.13–1.22), indicating 17 % lateral retinal stretching or expansion by the processing. Thickness measurements in histology were 65.6 % of the in-vivo thickness as measured in OCT, indicating 1/3 axial tissue compression or shrinkage.

Conclusions

We provide an analysis of retinal tissue deformation after fixation in Margo’s solution and paraffin embedding. In spite of protocol optimization for reduced tissue deformation, the workup caused 1/3 axial compression/shrinkage and 17 % lateral elongation, which was unexpected. We show a simple way how to calibrate retina specimens by fundus photography and OCT, two methods that are readily available to most ophthalmologists. Our findings underline the necessity to calibrate specimens prior to morphometry.