Retinal and optic nerve evaluation by optical coherence tomography in adults with obstructive sleep apnea–hypopnea syndrome (OSAHS)

Objective

To assess the peripapillary retinal nerve fiber layer (RNFL) thickness, optic nerve head (ONH) morphologic parameters, and macular thickness and volume in patients affected by obstructive sleep apnea–hypopnea syndrome (OSAHS).

Methods

This prospective, observational case-control study consisted of 96 eyes of 50 OSAHS patients (mean age of 50.9?±?12.4 years, best-corrected visual acuity ≥20/20, refractive error less than 3 spherocylindrical diopters, and intraocular pressure <21 mmHg) who were enrolled and compared with 64 eyes of 33 age-matched controls. Peripapillary RNFL thickness, ONH parameters, macular thickness and volume were measured by optical coherence tomography (OCT).

Results

OSAHS patients showed a significant reduction of the nasal quadrant RNFL thickness (74.7?±?15.8 μm) compared with those values observed in control patients (81.1?±?16.6 μm, p?=?0.047, Student's t-test). No differences in peripapillary RNFL thickness were observed when dividing the OSAHS group in accordance with disease severity. Vertical integrated rim area (VIRA) (0.67?±?0.41 mm³ in OSAHS vs 0.55?±?0.29 mm³ in controls; p?=?0.043, Student's t-test), horizontal integrated rim width (HIRW) (1.87?±?0.31 mm² in OSAHS vs 1.8?±?0.25 mm² in controls; p?=?0.039, Student's t-test) and disc area (2.74?±?0.62 mm² in OSAHS vs 2.48?±?0.42 mm² in controls; p?=?0.002, Student's t-test) showed significant differences, all of them being higher in the OSAHS group. Severe OSAHS had significant higher disc area (2.8?±?0.7 mm²) than controls (2.5?±?0.4 mm²; p?=?0.016, ANOVA test). Temporal inner macular thickness was significantly higher in mild–moderate OSAHS patients (270?±?12 μm) than in severe OSAHS patients (260?±?19 μm; p?=?0.021, ANOVA test).

Conclusions

OSAHS patients showed decreased peripapillary nasal RNFL thickness, and increased ONH area and volume parameters when they were evaluated by OCT. These findings suggest that neuronal degeneration might be present in the retina of OSAHS patients, as previously observed in some neurodegenerative disorders     

Comparison of Spectralis-OCT, GDxVCC and GDxECC in assessing retinal nerve fiber layer (RNFL) in glaucomatous patients

Background

Glaucomatous optic neuropathy is characterized by a progressive loss of retinal ganglion cells (RGCs). The defects in the peripapillary retinal nerve fiber layer (RNFL) have been reported to be the earliest sign of glaucoma. We determined the agreement between RNFL thickness assessments from spectral-domain OCT (Spectarlis HRA?+?OCT; Heidelberg Engeneering, Heidelberg, Germany), scanning laser polarimetry (SLP) with variable cornea compensation (GDxVCC; Carl Zeiss Meditec, Dublin, CA, USA), and SLP with enhanced cornea compensation (GDxECC; Carl Zeiss Meditec, Dublin, CA, USA) in glaucomatous patients. Furthermore, we investigate the influence of typical scan score (TSS) on the results of GDx assessments.

Methods

The enrolled subjects were devided into different groups by modified HODAPP visual field criteria. The peripapillary RNFL thickness was assessed with the three devices . ANOVA test, Pearson and Spearman correlation coefficient, and Bland-Altman plots were used to analyse the RNFL thickness assessments.

Results

Ninety-two eyes from 92 glaucomatous subjects were analysed. These were divided into four groups: preperimetric glaucoma (n?=?26), mild glaucoma (n?=?18), moderate glaucoma (n?=?21), and severe glaucoma (n?=?27). For Spectralis-OCT, the average RNFL thickness (mean ± SD) was 99.25?±?26.31 μm, 80.52?±?16.63 μm, 71.59?±?21.15 μm, and 63.85?±?20.86 μm for preperimetric, mild, moderate, and severe glaucoma respectively. For GDxVCC, the corresponding assessments were 52.63?±?8.18 μm, 52.95?±?10.20 μm, 46.77?±?10.62 μm, and 49.70?±?13.34 μm. For GDxECC, the assessments were 49.35?±?6.52 μm, 45.92?±?7.21 μm, 42.19?±?8.00 μm, and 39.53?±?8.45 μm. All Spectralis-GDxVCC and Spectralis-GDxECC differences were statistically significant by ANOVA test. The differences between GDxVCC and GDxECC were statistically significant only for severe glaucoma. There was a highly significant correlation between Spectralis-OCT and GDxECC, as well as Spectralis-OCT and GDxVCC, in assessing the RNFL thickness. The best instrument agreement was found between GDxECC and Spectralis-OCT. The RNFL thickness assessed with Spectralis-OCT and GDxECC showed a better correlation to visual field defects than GDxVCC. Evaluating GDx assessments with typical retardation pattern GDxVCC and GDxECC showed very similar RNFL thickness results.

Conclusions

RNFL thickness assessments between GDxVCC, GDxECC, and Spectralis-OCT cannot be directly compared. The assessments are generally higher with Spectralis-OCT than with GDxVCC and GDxECC, because of differences in method of the devices. The atypical retardation pattern has a major impact on the RNFL thickness results of GDx devices. This must be taken into account when evaluating the assessed RNFL thickness results.     

Investigation of retinal nerve fiber layer thickness in patients with neurofibromatosis-1

Purpose

To compare the optical coherence tomography (OCT) findings of neurofibromatosis-1 (NF-1) patients with/without optic pathway glioma (OPG) with those of healthy controls.

Methods

Ten patients with NF-1, 17 patients with NF-1-associated OPGs, and 17 control subjects were included in the study. Retinal nerve fiber layer (RNFL) and macular thickness findings measured with Stratus OCT were compared between the groups.

Results

The average RNFL thickness was significantly lower in the OPG group (76.72 ± 22.16 μm) than in the controls (108.89 ± 9.92 μm) and NF-1 patients without OPGs (111.17 ± 12.13 μm) (p < 0.001). The macular volume was also found to be lower in NF-1 patients with OPG (6.41 ± 0.66 mm³) than in the healthy controls (7.19 ± 0.36 mm³; p = 0.001) and NF-1 patients without OPGs (7.25 ± 0.26 mm³; p = 0.005). Following this analysis the OPG group was further subdivided into two categories: OPG patients with normal visual acuity (VA) and OPG patients with decreased VA. The statistical analysis was repeated for these four subgroups, revealing that while the decrement in the average RNFL thickness was significant for both OPG groups that in the macular volume was only significant for OPG patients with decreased VA.

Conclusion

The results of our study suggest that RNFL thinning can be a helpful marker for the detection of OPGs in NF-1 patients. Larger studies with longitudinal data are required to confirm the role of OCT in the diagnosis and follow-up of these patients.     

Pattern electroretinogram in neuromyelitis optica and multiple sclerosis with or without optic neuritis and its correlation with FD-OCT and perimetry

Purpose

To evaluate the ability of transient pattern electroretinogram (PERG) parameters to differentiate between eyes of patients with neuromyelitis optica (NMO), longitudinally extensive transverse myelitis (LETM), multiple sclerosis with optic neuritis (MS + ON), multiple sclerosis without optic neuritis (MS ? ON), and controls, to compare PERG and OCT with regard to discrimination ability, and to assess the correlation between PERG, FD-OCT, and visual field measurements (VFs).

Methods

Visual field measurements and full-field stimulation PERGs based on both 48- and 14-min checks were obtained from patients with MS (n = 28), NMO (n = 20), LETM (n = 18), and controls (n = 26). In addition, FD-OCT peripapillary retinal nerve fiber layer (RNFL) and segmented macular layer measurements were obtained and their correlation coefficients were determined.

Results

Compared to controls, PERG amplitude measurements were significantly reduced in eyes with NMO and MS + ON, but not in eyes with LETM and MS ? ON. PERG amplitudes were significantly smaller in NMO and MS + ON eyes than in MS ? ON eyes. PERG and OCT performance was similar except in NMO eyes where macular thickness parameters were more efficient at detecting abnormalities. A significant correlation was found between N95 amplitude values and OCT-measured macular ganglion cell layer thickness, total retinal thickness, and temporal peripapillary RNFL thickness. PERG amplitude was also significantly associated with VF sensitivity loss. No statistically significant difference was observed with regard to the best-performing parameters of the two methods.

Conclusions

Pattern electroretinogram measurements were able to detect RNFL loss in MS + ON and NMO eyes, with a performance comparable to OCT. PERG amplitude measurements were reasonably well correlated with OCT-measured parameters.     

Retinal vessel diameter in normal-tension glaucoma patients with asymmetric progression

Purpose

To investigate the longitudinal changes in the central retinal vessel diameter in asymmetric progressive normal-tension glaucoma (NTG) patients.

Methods

This study included 27 patients with bilateral NTG without any systemic vascular disease who showed glaucomatous progression in one eye at the mean follow-up of 24.3 months (range, 18–29 months). Progression was determined by the development of new retinal nerve fiber layer (RNFL) defects or widening of pre-existing defects on red-free RNFL photographs. The central retinal arteriolar equivalent (CRAE) and the central retinal venular equivalent (CRVE) were measured at baseline and at the mean follow-up of 24.3 months. We classified the eyes of each patient as either progressed or stable eyes, and compared the differences and changes in the CRAE and CRVE.

Results

No significant inter-eye difference was observed at baseline in the mean CRAE (167.5?±?22.2 μm vs. 168.2?±?15.5 μm, p?=?0.809) and in the mean CRVE (276.3?±?18.2 μm vs. 281.6?±?21.9 μm, p?=?0.267) between the progressed and stable eyes. There were significant changes in CRAE in the progressed eyes between baseline and 2 years after baseline (from 167.5?±?22.2 μm to 146.9?±?18.0 μm, p?p?=?0.084).

Conclusions

In our series of NTG patients with asymmetric progression, central retinal artery diameter decreased over time in the progressed eyes, whereas no significant decrease in the central retinal artery diameter was seen in the stable eyes.     

Relationship between disc margin to fovea distance and central visual field defect in normal tension glaucoma

Background

To investigate the relationship between ocular geometric factors, including temporal disc margin to fovea distance (DFD) measured by optic disc stereophotography (ODP) and central visual field (VF) defect, in normal-tension glaucoma (NTG) patients.

Methods

This retrospective, single-center, cross-sectional study included 88 eyes of 88 NTG patients with mild VF defects (MD?>??6.0 dB). NTG patients were divided into two groups according to VF tests: central VF-invading and central VF-sparing groups. Optic nerve head (ONH) parameters including disc dimensions, peripapillary atrophy (PPA), and DFD were obtained by ODP, and retinal nerve fiber layer (RNFL) thickness was measured by Stratus optical coherence tomography (OCT).

Results

In the invading group, DFD was shorter (3.642?±?0.401 mm) than in the sparing group (3.877?±?0.278 mm; p?=?0.002). The sparing group had more vertically oval ONH (p?=?0.023) and wider temporal PPA width (p?=?0.031). The RNFL thickness in the invading group was thinner in the temporal and inferior quadrants, but thicker in the superior quadrant than that of the sparing group. In a multiple linear regression analysis, DFD was the only geometric factor associated with degree of central VF involvement (p?=?0.002). DFD was positively correlated with temporal RNFL thickness in the sparing group (r?=?0.484, p?<?0.001) but not in the invading group (r?=??0.080, p?=?0.631).

Conclusions

Eyes with a shorter DFD should be monitored carefully because central VF involvement appears to be related to shorter DFD in NTG patients with mild VF defects.     

Evaluation of relationship between retinal nerve fiber layer thickness progression and visual field progression in patients with glaucoma

Purpose

To evaluate the capability of optical coherence tomography (OCT), retinal nerve fiber layer (RNFL) thickness, and visual field (VF) measurements in glaucoma progression detection.

Methods

The study examined 62 eyes of 37 glaucoma patients observed over a 3-year period. All eyes underwent at least four serial RNFL measurements performed by Cirrus OCT, with the first and last measurements separated by at least 3 years. VF testing was performed by using the Swedish interactive threshold algorithm (SITA) Standard 30-2 program of the Humphrey field analyzer (HFA) on the same day as the RNFL imaging. Both serial RNFL thicknesses and VF progression were assessed by the guided progression analysis (GPA) software program. RNFL thickness progression was evaluated by event analysis. Total deviation (TD) in the superior or inferior hemifield was also examined.

Results

A total of 295 OCT scans and 295 VFs were analyzed. Five eyes exhibited progression by OCT only and 8 eyes exhibited progression by VF GPA only. When the analysis was based on the combined measurement findings, progression was noted in 6 eyes. The average of the progressive hemifield TD at baseline for combined RNFL and VF progression was ?3.21 ± 1.38 dB, while it was ?2.17 ± 1.14 dB for RNFL progression and ?9.12 ± 3.75 dB for VF progression. The average of the progressive hemifield TD indicated a significant advancement of VF progression as compared to RNFL progression (P = 0.002).

Conclusions

When a mild VF defect is present, OCT RNFL thickness measurements are important in helping discern glaucoma progression.     

Correlation between early retinal nerve fiber layer loss and visual field loss determined by three different perimetric strategies: white-on-white,frequency-doubling,or flicker-defined form perimetry

Purpose

To compare the significance of white-on-white standard automated perimetry (SAP), matrix frequency doubling technology (FDT), and flicker-defined form perimetry (FDF) for early detection of nerve fiber layer loss in early glaucoma patients.

Methods

Fifty-one healthy controls and 40 patients with early glaucomatous nerve fiber loss were enrolled in this study. Patients had retinal nerve fiber layer (RNFL) imaging and visual field testing by SAP, FDT matrix, and FDF perimetry at the same visit. Visual field defects were confirmed with two or more consecutive examinations by the same types of perimetry. Significant retinal nerve fiber layer loss and thus early glaucoma was defined with the reference to the RNFL thickness deviation map. The sensitivity, specificity, correlation, MD (mean deviation) and PSD (pattern standard deviation) visual field indexes, and area under the receiver operating characteristic curve (AUC) of MD and PSD of the perimetries were compared.

Results

There was a significant difference in nerve fiber layer thickness between healthy patients (97.7 ± 1.34 μm and patients with early glaucoma (84.1 ± 1.58 μm) (p?p?0.6. AUCs of PSD were not reliable in all of the three VF devices.

Conclusions

The sensitivity for detection of RNFL loss in early glaucoma seems to be higher in FDF and FDT matrix than SAP perimetry, while specifity was highest in SAP. Thus, simultaneous performance of FDF/FDT matrix and SAP perimetry seems beneficial for the correct diagnosis of early glaucoma in patients.     

Scanning laser ophthalmoscopic parameters of eyes with exfoliation syndrome

Purpose

To evaluate optic nerve head (ONH) characteristics in patients with exfoliation syndrome (EXS).

Methods

This was a cross-sectional, observational study in which 73 eyes from 73 patients with EXS and 93 eyes from 93 age-matched healthy subjects who met the inclusion criteria were included. Topographic measurements of the ONH and peripapillary retinal nerve fiber layer (RNFL) thickness were performed by confocal scanning laser ophthalmoscopy, using a Heidelberg retina tomograph. Outcomes of interest were studied by Student t test and χ-squared test.

Results

EXS patients and age-matched controls did not differ in ONH parameters. Nevertheless, the mean cup depth and height variation contour values were higher in the normal subjects (P = 0.07, P = 0.056, respectively). Mean RNFL thickness was 0.22 ± 0.06 mm in the EXS group and 0.26 ± 0.06 mm in the control group, (P = 0.001). Likewise, the RNFL cross-sectional area was significantly lower in exfoliative eyes (1.16 ± 0.35 mm²) than in those of the control group (1.31 ± 0.33 mm²) (P = 0.006).

Conclusions

No significant differences in ONH parameters between EXS patients and age-matched healthy subjects were observed; however, RNFL measurements in eyes with EXS showed lower values.     

Comparison of cornea endothelial cell counts after combined phacovitrectomy versus pars plana vitrectomy with fragmentation

Background

To compare postoperative cornea endothelial cell loss between combined phacovitrectomy and pars plana vitrectomy (PPV) with fragmentation.

Methods

Eighty-eight consecutive patients (92 eyes) who underwent combined phacovitrectomy (53 eyes from 50 patients) or PPV with fragmentation (39 eyes from 38 patients) were enrolled in this retrospective study. Endothelial cell density (ECD) was calculated with specular microscopy at 1 and 3 months after surgery.

Results

At 3 months after surgery, the mean ECD decreased significantly from 2,646?±?296 cells/mm² to 2,422?±?347 cells/mm² in the combined phacovitrectomy group (P?<?0.001). However, the PPV with fragmentation group did not show any significant changes in ECD during the same period (from 2,123?±?628 cells/mm² to 2,073?±?574 cells/mm²). The mean endothelial cell loss in the combined phacovitrectomy group (7.9 and 9.5 %) was significantly higher than that in the PPV with fragmentation group (0.7 and 2.4 %) both at 1 and 3 months postoperatively (P?=?0.001 and P?=?0.001 respectively).

Conclusion

In this study, corneal endothelial cell loss during the early postoperative period was significantly higher after combined phacovitrectomy than after PPV with fragmentation.     

Investigation of blood flow regulation and oxygen saturation of the retinal vessels in primary open-angle glaucoma

Purpose

To examine the supply of oxygen to the retina in primary open-angle glaucoma (POAG).

Methods

Forty-one patients with primary open-angle glaucoma (mean age 64.1?±?12.9 years) and 40 healthy subjects (63.6?±?14.1 years) were included. Fundus images, centered at the optic disc, were taken using the Retinal Vessel Analyzer (RVA). The vessel diameters were calculated as central retinal artery (CRAE) and vein equivalent (CRVE) from diameter measurements in the peripapillary vessels. The oxygen saturation of the arteries and veins was investigated employing a two-wavelengths technique. After the measurement at baseline, the vascular response to flicker light exposure was measured.

Results

In glaucoma patients the mean oxygen saturation of the retinal veins at baseline was higher than in the healthy controls (64.36?±?7.11 vs. 59.78?±?8.47, p?=?0.01), whereas the mean arteriovenous oxygen saturation difference was lower (33.07?±?5.24 vs. 37.53?±?6.95, p?=?0.002). The arterial oxygen saturation as well as the arterial and venous diameters showed no difference between the groups. The increase of the CRVE during flicker light stimulation (3.72?±?3.29 % vs. 5.43?±?4.04, p?=?0.039), as well as the change of the venous oxygen saturation (2.08?±?3.74 % vs. 4.18?±?3.88 %, p?=?0.016) and the arteriovenous saturation difference (?2.1?±?3.31 % vs. ?4.43?±?3.6 %, p?=?0.003) were smaller in POAG patients than in the healthy group.

Conclusions

The reduction in the arteriovenous difference in oxygen saturation in POAG patients might show a decreased oxygen demand of the retina caused by the glaucomatous loss of neuroretinal tissue. The lower extent of the flicker light-induced change of the diameter of retinal veins and the venous oxygen saturation could indicate an impairment of blood flow regulation.     

Pattern ERG and RNFL thickness in hypertensive eyes with normal blue-yellow visual field

Purpose

To evaluate the transient pattern electroretinogram (t-PERG) and the retinal nerve fiber layer (RNFL) thickness in eyes with ocular hypertension (OH) and normal short-wavelength automated perimetry (SWAP).

Methods

In 26 patients with bilateral OH with normal SWAP, and in 26 age and sex matched healthy controls, t-PERG recording and RNFL thickness measurement were performed. Mean deviation (MD) and pattern standard deviation (PSD) of a reliable full threshold 24-2 SWAP were considered. RNFL thickness was determined by OCT3. Monocular PERG were recorded by using a black and white checkerboard pattern (check size 0.9°, contrast 100 %, mean luminance 80 cd/m2) generated on a monitor and reversed in contrast (four reversals per second, 2 Hz) at a distance of 70 cm. Patients had optimal correction at viewing distance; no mydriatic or miotic eye drops were used. Silver/silver chloride skin electrodes were placed over the lower eyelids in the stimulated eye (active electrode) and in the patched eye (reference electrode); ground electrode was in the Fpz scalp. Peak-to peak amplitude of P50 (N35-P50) and N95 (P50-N95) waves, and implicit time of P50, were considered.

Results

Compared to controls, in OH eyes, a reduction of N35-P50 amplitude (2.86?±?1.49 vs. 3.77?±?1.08 microvolts, ?24.1 %, t-test p?=?0.015), of average RNFL thickness (88?±?11 vs. 96?±?10 μm, ?9.5 %, t-test p?=?0.002), and of RNFL thickness in superior (p?=?0.015) and inferior quadrant (p?<?0.001), were found. Multivariate analysis showed that in OH eyes, N35-P50 amplitude was inversely related to intraocular pressure (IOP) (p?=?0.001); no correlation was found between N35-P50 amplitude and MD, PSD, CCT or RNFL thickness.

Conclusions

In OH eyes, both PERG and RNFL thickness changes occur in hypertensive eyes with undamaged SWAP; the correlation of PERG amplitude with IOP, but not with RNFL thickness, suggests that such PERG changes are an effect of the IOP on retinal ganglion cells, rather than a sign of their loss.     

Comparison of ganglion cell and retinal nerve fiber layer thickness in primary open-angle glaucoma and normal tension glaucoma with spectral-domain OCT

Background

The aim of this study was to evaluate the macular thickness (MT), ganglion cell complex (GCC), and circum-papillary retinal nerve fiber layer (RNFL) thickness in primary open-angle glaucoma (POAG) and normal tension glaucoma (NTG) with spectral domain optical coherence tomography (SD-OCT).

Methods

A total of 169 subjects were enrolled: 52 normal subjects, 61 with POAG, and 56 with NTG. Spectral-domain optical coherence tomography (SD-OCT) was used to analyze MT, GCC, and RNFL thickness. To compare the discrimination capabilities between the MT, GCC, and RNFL thickness measurements, we analyzed the areas under the receiver operating characteristic (ROC) curves (AUCs). The relationships between GCC and RNFL measurement and also the relationships of the groups, with age, gender, GCC, and RNFL thickness were assessed.

Results

Normal subjects showed the thickest superior and inferior GCC, followed by in order NTG and POAG (p?<?0.05). While there was a statistically difference in MT value of the normal subjects and the glaucoma patients (p?<?0.05), MT value did not differ between POAG and NTG (p?<?0.05). RNFL thickness parameters were significantly greater in normal subjects, followed in order by the NTG, and POAG (p?<?0.05). Between the normal and entire glaucoma groups, all GCC and RNFL parameters showed the similar discrimination power. RNFL thickness parameters correlated significantly with all GCC thickness (p?<?0.05). Superior RNFL thickness was the only independent variable between the POAG and NTG patients (odds ratio (OR) 0.942, p?=?0.004, 95 %CI 0.905–0.981).

Conclusions

SD-OCT evaluation results suggest higher GCC and RNFL parameters for NTG than POAG.     

Subbasal nerve morphology, corneal sensation, and tear film evaluation after refractive femtosecond laser lenticule extraction

Background

The purpose of this study was to compare corneal subbasal nerve morphology, corneal sensation, and tear film parameters after femtosecond lenticule extraction (FLEX) and small-incision lenticule extraction (SMILE).

Methods

A prospective, randomized, single-masked, paired-eye design clinical trial of 35 patients treated for moderate to high myopia with FLEX in one eye and SMILE in the other. In both techniques, an intrastromal lenticule was cut by a femtosecond laser and manually extracted. In FLEX, a LASIK-like flap allowed removal of the lenticule, whereas in SMILE, it was removed through a small incision. In-vivo confocal microscopy was used to acquire images of the central corneal subbasal nerve plexus, from which nerve density, total nerve number, and nerve tortuosity were analyzed. Corneal sensation was measured using Cochet–Bonnet esthesiometry. A visual analog scale, tear osmolarity, non-invasive tear film break-up time (keratograph) tear meniscus height (anterior segment OCT), Schirmer's test, and fluorescein tear film break-up time were used to evaluate tear film and ocular surface symptoms. Patients were examined before and 6 months after surgery.

Results

There were no statistically significant differences in baseline parameters between FLEX and SMILE (p?>?0.050). With regard to changes from before to 6 months after surgery, mean reduction in subbasal nerve density was 14.22?±?6.24 mm/mm² in FLEX eyes, and 9.21?±?7.80 mm/mm² in SMILE eyes (p?<?0.05). The total number of nerves decreased more in FLEX eyes than in SMILE eyes (p?<?0.05). No change was found when comparing tortuosity (p?>?0.05). Corneal sensation was reduced with 0.38?±?0.49 cm in FLEX eyes, and 0.10?±?0.34 cm in SMILE eyes (p?<?0.01). No differences were found between FLEX and SMILE in tear film evaluation tests (p?>?0.05). Significantly more patients felt postoperative foreign body sensation in the FLEX eye within the first days after surgery, as compared to the SMILE eye.

Conclusions

Six months after surgery, the less invasive SMILE technique seemed better at sparing the central corneal nerves as compared to FLEX. Corneal sensation was only significantly reduced in FLEX eyes. There were no differences between FLEX and SMILE when comparing tear film evaluation tests 6 months after surgery.     

Clinical results of selective laser trabeculoplasty in silicone oil-induced secondary glaucoma

Background

To analyze the efficacy of selective laser trabeculoplasty (SLT) on silicone oil-induced secondary glaucoma in terms of intraocular pressure (IOP).

Patients and Methods

42 patients (42 eyes) with silicone oil-induced secondary glaucoma were selected, and SLT was performed with 360° of the trabecular meshwork. During the 12-month follow-up, the complications, IOP, and antiglaucoma medication usage were observed.

Results

The mean IOP decreased from 23.1?±?1.9 mmHg before treatment to 18.4?±?3.7 mmHg after treatment (p?<?0.05). Mean number of antiglaucoma medications used for IOP control also decreased from 2.17?±?1.21 to 1.25?±?0.89 (p?<?0.05). The 12-month success rate in the total sample was 59.5 %. The success rate was 60.7 % (17 eyes) and 57.1 % (eight eyes) for phakic and aphakic eyes, respectively (p?>?0.05)

Conclusions

SLT is a safe and effective option for the treatment of patients with silicone oil-induced secondary glaucoma.     

Optic disc rim area to retinal nerve fiber layer thickness correlation: comparison of diabetic and normal tension glaucoma eyes

Purpose

To compare the correlation between optic disc rim area and retinal nerve fiber layer thickness (rim-RNFL correlation) in diabetic eyes with non-progressive RNFL defects and normal tension glaucoma (NTG) eyes.

Methods

Seventy-three eyes of 73 patients with preperimetric or early NTG and 25 eyes of 25 type II diabetes patients with a non-progressive RNFL defect for ≥5 years were enrolled in this retrospective cohort study. Rim areas and RNFL thicknesses were measured by Heidelberg retina tomography (HRT II) and by optical coherence tomography (Cirrus OCT), in global and 12 clock-hour parameters. Diabetic eyes were evaluated whether they were above the 95 % prediction interval (PI) for the rim-RNFL correlation of NTG.

Results

A significant linear rim-RNFL correlation was observed in NTG eyes globally and at all clock-hours, except in the 4 and 9 o’clock areas, (0.08 < r ² < 0.56, P < 0.05). Eighty-four percent of the diabetic eyes were above the 95 % PI of the rim-RNFL correlation of NTG in ≥2 clock-hours, as compared with 36 % of the eyes in the global parameter.

Conclusions

The eyes of diabetic patients with non-progressive RNFL were well-differentiated from NTG eyes by the rim-RNFL correlation.     

Baseline thickness of macular ganglion cell complex predicts progression of visual field loss

Background

Previous studies reported that the thickness of the macular ganglion cell complex (mGCC) showed good diagnostic ability for detecting glaucoma. However, its impact on the progression of visual field loss in primary open angle glaucoma (POAG) is unknown. The purpose of this study was to assess whether baseline mGCC thickness is associated with the progression of visual field loss in POAG.

Methods

Fifty-six patients with POAG were included in the study. All patients were followed for more than 2 years after baseline optical coherence tomography (OCT) measurements. They had at least five reliable Humphrey visual field tests with 30–2 Swedish Interactive Threshold Algorithm standard tests during the follow-up period. The subjects were divided into two groups according to the slope of the mean deviation (MD): the fast progression group (MD slope < ?0.4 dB/y) and the slow progression group (MD slope ≥ ?0.4 dB/y). Factors compared between the groups were as follows: age, baseline intraocular pressure (IOP), mean IOP during the follow-up, refraction, baseline MD, pattern standard deviation (PSD), and baseline OCT measurements.

Results

There were no significant differences between the two groups in age, baseline IOP, mean IOP during the follow-up, refraction, baseline MD or PSD, average thickness of retinal nerve fiber layer (RNFL), or disc parameters. However, the baseline mGCC thickness (average and inferior hemifield) was significantly thinner in the fast progression group than in the slow progression group (74.0?±?7.2 μm vs. 80.3?±?8.6 μm; 68.0?±?6.6 μm vs. 78.2?±?11.6 μm, respectively). Moreover, global loss volume and focal loss volume, which are parameters of mGCC, showed significantly higher rates in the fast progression group than in the slow progression group. In multivariate analysis, only mGCC thickness of the inferior hemifield was associated with disease progression (P?=?0.007).

Conclusions

Baseline mGCC thickness can be predictive of progressive visual field loss in patients with POAG.     

Relationship between corneal hysteresis and optic nerve parameters measured with spectral domain optical coherence tomography

Background

Corneal hysteresis (CH) has been associated with visual field damage in glaucoma and is related to the velocity of perimetric glaucoma progression. We undertook this investigation to determine whether CH is associated with structural markers of glaucoma damage on spectral domain optical coherence tomography (SD-OCT).

Methods

In this retrospective study, 131 patients under glaucoma evaluation were evaluated with SD-OCT (Cirrus; Carl Zeiss Meditec, Dublin, CA) and had CH measurements with the ocular response analyzer (Reichert, Inc., Buffalo, NY). Pearson and partial correlation adjusting for age were preformed to examine the association between CH and variables of interest. Generalized estimating equations were used to construct simple and multiple linear models.

Results

While Pearson correlations were modest overall, CH best correlated with mean deviation (MD; r?=?0.19) followed by average retinal nerve fiber layer (RNFL) thickness (r?=?0.18) and vertical cup to disc ratio (r?=??0.11) in the open angle glaucoma group. In univariable models, CH varied as a function of MD (ß?=?0.1, 95 % CI 0.03, 0.1; p?<?0.001) and of average RNFL thickness (ß?=?0.2, 95 % CI 0.1, 0.4; p?=?0.001). In a multivariable analysis including MD, age, average RNFL thickness, and glaucoma status, MD (p?=?0.001) and age (p?<?0.001) retained significant associations with CH.

Conclusions

In patients under evaluation and treatment for glaucoma, CH was more closely related to visual field MD than to structural markers of glaucoma damage as measured by SD-OCT.     

Trans-conjunctival aqueous humor outflow in glaucomatous patients treated with prostaglandin analogues: an in vivo confocal microscopy study

Purpose

To analyze, using in vivo laser scanning confocal microscopy (LSCM), the conjunctival features in glaucomatous patients receiving prostaglandin analogues (PGA).

Methods

Eighty eyes of 80 consecutive glaucomatous patients naive for therapy were enrolled; 30 eyes of 30 healthy subjects served as a control. Patients were randomized to: preservative-free (PF) and preserved latanoprost (groups 1 and 2, respectively), PF and preserved timolol (groups 3 and 4), and controls to vehicle of latanoprost or physiological buffered saline solution (groups 5 and 6). All subjects underwent LSCM of bulbar conjunctiva at baseline and 3 months after initiating therapy. The main outcomes were: mean density (MMD: cysts/mm²) and mean area (MMA: cysts/mm²) of epithelial microcysts. The relations between MMA and MMD with intraocular pressure (IOP), age, and mean defect (MD), were analyzed.

Results

At baseline, microcysts were found in all subjects. At month three, MMD did not change in all groups (p?>?0.05). MMA significantly increased only in group 1 from 2,158.81?±?524.09 to 3,877.77?±?867.31, and in group 2 from 2,019.71?±?541.03 to 5,560.39?±?1,176.14, with values significantly higher in group 2 (p?p?>?0.05).

Conclusions

PGA increased MMA in therapy-naive glaucomatous patients, indicating a possible enhancement of the trans-conjunctival aqueous humor outflow. Therefore, conjunctiva seems an additional target tissue to evaluate the hydrodynamic pathways in glaucoma and modifications induced by medical therapy.     

Intravitreal injection of 99Tc-MDP inhibits the development of laser-induced choroidal neovascularization in rhesus monkeys

Background

The aim of this study was to investigate the safety and efficacy of intravitreal injection of ⁹⁹Tc-MDP, a decay product of ^99mTc-MDP, on the development of laser-induced choroidal neovascularization (CNV) in rhesus monkeys.

Methods

Experimental CNV was induced by argon laser with a small high-energy laser spot. Monkeys were given 50 μL of ⁹⁹Tc-MDP at a concentration of 0.005 μg/mL (n?=?6) or 0.01 μg/mL (n?=?6) by intravitreal injection once a week immediately after laser injury for a period of 56 days. Control animals were treated with the same volume of PBS (n?=?6) in the same way. Eyes were monitored by ophthalmic examination, color fundus photography, fluorescence fundus angiography (FFA), optical coherence tomography (OCT) and histology. Incidences of grade 4 CNV lesions as well as the leakage areas of grade 4 CNVs on the late-phase of fluorescein angiograms were measured in a standardized, randomized and masked fashion fortnightly. The maximum widths and heights of grade 4 CNVs were also calculated by histology at the end of the experiment. Toxicity of ⁹⁹Tc-MDP on the retina was evaluated by electroretinogram (ERG) and histologic analysis.

Results

⁹⁹Tc-MDP reduced the incidences of grade 4 CNVs by 33.33 % and 39.40 % in the 0.005 μg/mL and 0.01 μg/mL groups, respectively, compared with the PBS group on day 28 (P?<?0.05; n?=?6). The leakage areas of grade 4 CNVs were smaller in the 0.005 μg/mL (0.7136?±?0.0283 mm², p <0.01; n?=?6) and 0.01 μg/mL (0.4351?±?0.0349 mm², p?<?0.01; n?=?6) groups than those in the PBS control group (0.9373?±?0.0455 mm²; n?=?6) in a dose-dependent manner on day 28. OCT and histology also showed that the sizes of CNVs were smaller in the ⁹⁹Tc-MDP treated groups than those in the PBS group. Although intravitreal injection of ⁹⁹Tc-MDP led to mild inflammatory reaction in the anterior chamber, histology and ERG findings demonstrated that ⁹⁹Tc-MDP did not cause any change in histological structure or function of the retina (p>0.05).

Conclusions

Intravitreal injection of ⁹⁹Tc-MDP can inhibit the development of laser-induced CNV without toxic effect on retina, suggesting that ⁹⁹Tc-MDP has therapeutic potential for CNV related diseases.