Impact of Choriocapillaris Flow on Multifocal Electroretinography in Intermediate Age-Related Macular Degeneration Eyes

Purpose

To investigate the relationship between perfusion of the choriocapillaris (CC) and macular function in eyes with intermediate age-related macular degeneration.

Methods

In this prospective, observational, cross-sectional study, macular optical coherence tomography angiography images and multifocal electroretinograms were obtained in 20 eyes with intermediate age-related macular degeneration from 20 patients. The main outcome measures were (1) the percent nonperfused choriocapillaris area (PNPCA), which represents a measure of the total area of CC vascular dropout, and (2) the average size of the CC signal voids, which represent contiguous regions of CC dropout. Furthermore, amplitude and implicit time of multifocal electroretinograms N1 and P1 waves in the two central rings (R1 and R2) were included in the analysis.

Results

Of the 20 patients enrolled, only 17 eyes from 17 patients (13 women) were included in this analysis. Three patients were excluded because of poor scan quality. Mean ± SD age was 75.1 ± 7.9 years (range, 62-89 years). The best corrected visual acuity was 0.17 ± 0.13 logarithm of the minimum angle of resolution. In univariate analysis, both the PNPCA and average signal void size were found to have a significant direct relationship with N1 implicit time in the R2 ring (P = 0.006 and P = 0.035, respectively). Neither PNPCA nor the average signal void size was associated with P1 or N1 implicit times in R1.

Conclusions

In intermediate age-related macular degeneration eyes, PNPCA and average signal void size are related to N1 multifocal electroretinogram implicit times, which suggests an association between CC perfusion and photoreceptor function.

Optical Coherence Tomography Angiography Findings in X-Linked Retinoschisis

BACKGROUND AND OBJECTIVE

The aim of the study was to determine optical coherence tomography angiography (OCTA) findings and to identify mutations in the RS1 gene in a three-generation family with X-linked juvenile retinoschisis (XLRS).

PATIENTS AND METHODS

Clinical and genetic assessments were performed in 12 family members. OCTA was performed at baseline (12 members including cases and carriers) and after acetazolamide administration (three cases). Twenty healthy subjects (20 eyes, controls) were chosen for comparison. Molecular genetic analysis of the RS1 gene was performed in all family members.

RESULTS

Deep capillary plexus density was reduced in cases compared with controls (P < .01) and was negatively related with retinal thickness (P < .05). After treatment, retinal thickness decreased (P < .05) and deep capillary plexus density increased (P < .05) in cases. In three cases and in four carriers, p.Arg197 His mutation was found.

CONCLUSION

OCTA shows reduced macular deep vessel density in patients with XLRS probably related to vessel displacement and disruption due to schitic cysts. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:e20-e31.].

Radial Peripapillary Capillary Network in Patients with Retinitis Pigmentosa: An Optical Coherence Tomography Angiography Study

Purpose

To investigate radial peripapillary capillary (RPC) network in patients affected by retinitis pigmentosa (RP).

Methods

Eleven patients (22 eyes) with previous diagnosis of RP and 16 age-matched healthy subjects (16 eyes) were enrolled. The diagnosis of RP was made based on both clinical features and electrophysiological examination. All patients underwent a complete ophthalmologic examination, including optical coherence tomography angiography and visual field (VF). The primary outcomes were the RPC vessel density in the peripapillary and disk areas; the secondary outcomes were the peripapillary retinal nerve fiber layer (RNFL) thickness and the mean defect at VF.

Results

A total of 19 eyes of 11 RP patients (5 males, 6 females) and 16 eyes of 16 healthy subjects (10 males, 6 females) were included for the analysis. RPC vessel density in the disk area was 46.5 ± 7.1% in the RP group and 45.4 ± 10.6% in the control group (p = 0.754). RPC vessel density in the peripapillary area was significantly reduced in the RP group after the comparison with the control group (52.5 ± 5.0 and 57.2 ± 5.1%, respectively, p = 0.011). RNFL thickness was 85.9 ± 20.4 μm in the RP group and 104.0 ± 6.4 μm in the control group (p = 0.002). RPC vessel density was significantly correlated with RNFL thickness values in RP patients, both in the disk and in the peripapillary area (Rho = 0.599 and p = 0.007 in the disk area, Rho = 0.665 and p = 0.002 in the peripapillary area, respectively).

Conclusion

We showed that density of RPC is reduced in these patients in the peripapillary area. Moreover, the RPC vessel density correlates with the RNFL thickness.

Foveal avascular zone area and parafoveal vessel density measurements in different stages of diabetic retinopathy by optical coherence tomography angiography

AIM

To investigate foveal avascular zone (FAZ) and parafoveal vessel densities (PRVD) by means of optical coherence tomography angiography (OCTA) in diabetic patients with or without diabetic retinopathy (DR) and to assess the reproducibility of FAZ and PRVD measurements.

METHODS

Sixty diabetic patients (60 eyes) with different stage of DR (graded according to the International Clinical Severity Scale for DR) and 20 healthy subjects underwent FAZ area and PRVD measurements using OCTA by two experienced examiners. FAZ area in all patients was also assessed using fluorescein angiography (FA).

RESULTS

In subject with proliferative DR and with moderate-severe non proliferative DR, FAZ area was significantly increased compared to healthy controls (P=0.025 and P=0.050 respectively measured with OCTA and P=0.025 and P=0.048 respectively measured with FA). OCTA showed significantly less inter-observer variability compared to FA. Concordance correlation coefficient (CCC) for FAZ area measurements was 0.829 (95%CI: 0.736-0.891) P<0.001 with FA and 1.000 (95%CI: 0.999-1.000) P<0.001 with OCTA. CCC was 0.834 (95%CI: 0.746-0.893) P<0.001 and 0.890 (95%CI: 0.828-0.930) P<0.001 for parafoveal superficial and deep vessel density measurements, respectively.

CONCLUSION

OCTA shows progressive increase of FAZ area and reduction of PRVD in both superficial and deep plexus at increasing DR severity. FAZ area and PRVD measurements using OCTA are highly reproducible.

Microvascular changes after vitrectomy with internal limiting membrane peeling: an optical coherence tomography angiography study

PURPOSE

To evaluate superficial capillary plexus (SCP) changes occurring after internal limiting membrane (ILM) peeling for the treatment of idiopathic epiretinal membrane (ERM).

METHODS

A total of 15 eyes of 15 patients affected by idiopathic ERM (eight males and seven females; mean age 59.8 ± 9.6 years) were enrolled in the study. Patients were treated with pars plana vitrectomy followed by ERM and ILM peeling. Subjects were evaluated at baseline and at the week-1 and month-1 follow-up visits. At each visit, patients were evaluated with a complete ophthalmologic evaluation, which included imaging with optical coherence tomography angiography.

RESULTS

Overall, the SCP vessel density was 43.0 ± 3.0% at baseline and was stable throughout the follow-up (40.0 ± 4.0% at week-1 and 41.0 ± 4.0% at month-1 follow-up visits; p = 0.087 and p = 0.426, respectively). Nevertheless, the SCP vessel density was reduced at week-1 visit in both the superior and inferior sectors. In these sectors, the superficial vessel density was still reduced at the month-1 follow-up visit.

CONCLUSIONS

We observed a reduction in the SCP vessel density occurring after pars plana vitrectomy with ILM peeling. The reduction is referred to those areas where other changes (e.g., swelling of the arcuate nerve fiber layer) have been already described. In theory, superficial vessel density modifications may be due to the direct surgical trauma to the inner retina, where the superficial plexus is contained, during the ILM grasping.

Optical Coherence Tomography Angiography in the Multimodal Imaging Evaluation of Interferon-Associated Retinopathy: A Case Report

The authors present the case of a 59-year-old woman in treatment with interferon alfa-2b for stage IV melanoma and widespread metastases who presented with interferon-associated retinopathy. An ocular examination revealed multiple retinal cotton-wool spots and hard exudates. Interferon treatment was suspended. The patient was followed up for 5 months following the baseline visit by means of en face optical coherence tomography (OCT), spectral-domain OCT, and OCT angiography. Multimodal imaging was useful in the follow-up of this condition, permitting the characterization of all the lesions hallmarking the interferon-retinopathy and showing that this illness was related to a reduction of the retinal vascular perfusion. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:498-504.].

Optical Coherence Tomography Angiography Findings in Stargardt Disease

Background

to assess vessel density of superficial capillary plexus (SCP), deep capillary plexus (DCP) and choriocapillaris (CC) in advanced Stargardt disease (STGD) using optical coherence tomography angiography (OCTA) and correlate these findings with macular function using pattern electroretinogram (PERG) and multifocal electroretinogram (mfERG).

Methods

Twelve patients (24 eyes) with advanced STGD underwent vessel densities and macular thickness measurements using OCTA. A control group of 24 healthy controls (24 eyes) was chosen for comparison. In the STGD group correlation between vessel density and macular thickness and between macular function and morphologic parameters were evaluated.

Results

Whole parafoveal vessel density (VD) of SCP was significantly lower in STGD group compared to the control group (p<0.05). Foveal VD and whole parafoveal VD of the DCP were significantly lower in STGD group compared to the controls (p<0.05). CC was significantly decreased in STGD compared to controls (p<0.05). Foveal macular thickness (MT), full parafoveal MT, and inner limiting membrane (ILM)-inner plexiform layer (IPL) parafoveal MT thickness were decreased in STGD eyes compared to controls (p<0.001). PERG and mfERG were both significantly reduced in STGD compared to controls (p<0.001). A direct correlation was found between full parafoveal MT and vessel density in the STGD group.

Conclusions

Patients with advanced STGD showed a reduction of SCP, DCP and CC compared to healthy eyes related to a reduction of total and ILM-IPL macular thickness. These results suggest that both retinal capillaris plexuses and choriocapillaris reduction occur in STDG along with inner and outer retinal thinning.

All laser cataract surgery compared to femtosecond laser phacoemulsification surgery: corneal trauma

The aim of this study was to evaluate corneal tissue trauma after femtosecond laser-assisted cataract surgery (FLACS) and phacoemulsification (femtophaco surgery) compared to FLACS and nanolaser emulsification (all laser surgery). This is a prospective nonrandomized clinical study conducted at the Ophthalmology Clinic, University "G. d'Annunzio" of Chieti-Pescara, Italy, involving forty-two eyes of 42 patients candidates to cataract surgery. Patients were enrolled in two groups: femtophaco surgery (group 1 with 21 eyes) and all laser surgery (group 2 with 21 eyes). Main outcome measures included uncorrected visual acuity and distance corrected visual acuity, corneal endothelial cell count, and corneal thickness at the tunnel site and at the center of the cornea. Best correct visual acuity was not significantly different between the two groups. Postoperatively, a significant decrement of endothelial cell count at the center of the cornea was observed in group 1 compared with preoperative values at 90 days (p < 0.001) while t remained stable in group 2. The central corneal thickness showed a statistically significant increase for both groups that reached a maximum thickness at 7 days and then returned to presurgery levels after 90 days for group 1 and after 60 days for group 2. The tunnel corneal thickness showed a statistically significant increase for both groups that reached a maximum thickness at 7 days, which did not return to presurgery level for group 1 but did return to presurgery levels after 60 days for group 2. All laser surgery induced lower central endothelial cell loss and lower increase of corneal thickness compared to femtophaco surgery.

Prismatic correction in patients affected by age-related macular degeneration

Objective: To evaluate by means of a controlled clinical trial the effectiveness and the tolerance of prismatic correction in improving visual function in patients affected by advanced bilateral age-related macular degeneration.

Setting: Department of Ophthalmology, Eye Clinic, University of Trieste.

Subjects and interventions: Each patient underwent an ophthalmologic examination, complete with distance visual acuity measurement using the Standard Early Treatment Diabetic Retinopathy Study chart. Patients were then randomly assigned to the treatment or control group. The treatment group received spectacles lenses with a prismatic correction of low power (5–7 prismatic dioptres) in the better eye.

Main measures: Visual acuity was measured at baseline and 1, 90, 180 and 360 days after prescription in both groups.

Results: The treatment group consisted of 14 patients, while the control group was of 14 patients. The prismatic correction was well tolerated in 85.7% of cases. Visual acuity in the treatment group improved mostly at three-month follow-up, with a slight further improvement at the sixand 12-month follow-ups, showing a statistically significant difference in comparison with the control group. No visual acuity improvement was registered in the control group.

Conclusion: Monolateral prismatic correction may be considered a viable means to improve visual function in patients affected by bilateral age-related macular degeneration at an advanced stage.

Uveo-scleral outflow pathways after ultrasonic cyclocoagulation in refractory glaucoma: an anterior segment optical coherence tomography and in vivo confocal study

AIMS

To evaluate, using anterior segment optical coherence tomography (AS-OCT) and in vivo confocal microscopy (IVCM), the uveo-scleral aqueous humour (AH) outflow pathways after ultrasonic circular cyclocoagulation (UCCC).

METHODS

Forty-four patients with refractory glaucoma underwent 4 or 6 s UCCC (group 1, 24 eyes; group 2, 20 eyes). UCCC was successful when the preoperative intraocular pressure (IOP) reduced by one-third. AS-OCT and IVCM were performed at baseline and at month 1 to evaluate the sclera and conjunctiva. The main outcomes were mean intra-scleral hyporeflective spaces area (MIHSA: mm²) at AS-OCT, mean density and area of conjunctival microcysts (MMD: cysts/mm²; MMA: µm²) at IVCM. The relations between MIHSA, MMA and MMD with IOP were analysed.

RESULTS

Mean baseline IOP was 26.9±2.8 mm Hg in group 1 and 27.5±4.0 in group 2. Intra-scleral hyporeflective spaces and microcysts were observed in both groups, without significant differences in MIHSA, MMA and MMD. At month 1, UCCC was successful in 63.6% of patients (41.6% in group 1, 80% in group 2), and IOP reduced to 18.8±3.2 (30.1%) and 17.1±2.7 mm Hg (38.7%), respectively (p<0.001). MIHSA showed a twofold and threefold increase in group 1 and 2 (p<0.05), with a significant difference between groups (p<0.05). MMA and MMD increased in both groups (p<0.05), with values higher in group 2 (p<0.05). Significant relations were found between MIHSA and IOP in both groups (p<0.01).

CONCLUSIONS

UCCC induced anatomical modifications of sclera and conjunctiva, which suggested that the trans-scleral AH outflow enhancement is one of the possible mechanisms exploited by ultrasounds to reduce IOP.

Postoperative IOL Axial Movements and Refractive Changes After Femtosecond Laser-assisted Cataract Surgery Versus Conventional Phacoemulsification

PURPOSE

To evaluate intraocular lens (IOL) axial movements and refractive changes during a 6-month follow-up period after femtosecond laser-assisted cataract surgery and conventional cataract surgery, investigate the influence of capsulorhexis features on postoperative IOL axial changes, and assess the prediction error for both techniques.

METHODS

Eighty eyes of 80 candidates for cataract extraction were randomized into two groups: femtosecond laser (40 eyes) and manual (40 eyes).

RESULTS

The overall anterior chamber depth variation was significantly lower in the femtosecond laser group compared to the manual group during follow-up (P<.001). At 30 and 180 days postoperatively, the mean spherical equivalent showed a hyperopic shift (0.09±0.28 diopters [D]) in the femtosecond laser group and a myopic shift in the manual group (-0.25±0.18 D). Median absolute error was not significantly different between the two groups with standard formulas ranging between 0.29 and 0.64 (Hoffer Q) in the femtosecond laser group and between 0.24 (SRK-T) and 0.55 D (Hoffer Q) in the manual group. There was a significant lower deviation from intended versus achieved capsulotomy/capsulorhexis area in the femtosecond laser group (P<.001) compared to the manual group. The femtosecond laser group showed better IOL centration compared to the manual group at all time periods (P<.001).

CONCLUSIONS

Femtosecond laser-assisted cataract surgery was related to a lower overall variability of anterior chamber depth compared to conventional cataract surgery with more stable postoperative refraction. The two techniques did not show significant differences of prediction error.

Retinal Changes Induced by Epiretinal Tangential Forces

Two kinds of forces are active in vitreoretinal traction diseases: tangential and anterior-posterior forces. However, tangential forces are less characterized and classified in literature compared to the anterior-posterior ones. Tangential epiretinal forces are mainly due to anomalous posterior vitreous detachment (PVD), vitreoschisis, vitreopapillary adhesion (VPA), and epiretinal membranes (ERMs). Anomalous PVD plays a key role in the formation of the tangential vectorial forces on the retinal surface as consequence of gel liquefaction (synchysis) without sufficient and fast vitreous dehiscence at the vitreoretinal interface. The anomalous and persistent adherence of the posterior hyaloid to the retina can lead to vitreomacular/vitreopapillary adhesion or to a formation of avascular fibrocellular tissue (ERM) resulting from the proliferation and transdifferentiation of hyalocytes resident in the cortical vitreous remnants after vitreoschisis. The right interpretation of the forces involved in the epiretinal tangential tractions helps in a better definition of diagnosis, progression, prognosis, and surgical outcomes of vitreomacular interfaces.

Central serous chorioretinopathy treated with navigated retinal laser photocoagulation: visual acuity and retinal sensitivity

BACKGROUND AND OBJECTIVE

To evaluate the effect of navigated retinal laser photocoagulation on visual acuity (VA) and retinal sensitivity in eyes with acute central serous chorioretinopathy (CSC).

PATIENTS AND METHODS

Prospective, noncomparative, interventional case series of 30 eyes of 29 patients with acute CSC were treated using navigated photocoagulation. Patients were monitored for 180 days.

RESULTS

Mean VA improved from 0.3 ± 0.1 to 0.1 ± 0.1 logMAR (P < .001). Mean retinal sensitivity within central 8° and 4° improved from 9.4 ± 4.7 dB to 14.9 ± 3.6 dB and from 9.0 ± 5.6 dB to 14.6 ± 4.2 dB respectively (P < .001). In all cases, a decrease in mean central retinal thickness of -50.6 ± 2.9 µm (P < .001) and in mean subretinal fluid thickness of -52.0 ± 3.3 µm (P < .001) was observed during follow-up.

CONCLUSION

Navigated retinal laser photocoagulation demonstrated safety and accuracy for the treatment of acute CSC. VA and retinal sensitivity evaluations showed a significant improvement associated with resolution of the subretinal fluid during follow-up.

Optical coherence tomography and 3-dimensional confocal structured imaging system-guided femtosecond laser capsulotomy versus manual continuous curvilinear capsulorhexis

PURPOSE

To compare the features of capsulotomy obtained during femtosecond laser-assisted cataract surgery with those of continuous curvilinear capsulorhexis (CCC) obtained using a standard manual technique.

SETTING

Ophthalmology Clinic, Department of Medicine and Science of Ageing, University G. D'Annunzio Chieti-Pescara, Chieti, Italy.

DESIGN

Prospective randomized clinical study.

METHODS

Candidates for cataract extraction were randomized into 1 of 3 groups as follows: Lensx femtosecond laser-assisted cataract surgery capsulotomy (laser group 1), Lensar femtosecond laser-assisted cataract surgery capsulotomy (laser group 2), and manual CCC (manual group).

RESULTS

Each group comprised 30 eyes (30 patients). The capsulotomies in laser group 1 and laser group 2 showed significantly better circularity than the manual CCCs at 7 days (P<.001). There was a significant correlation between the intended versus achieved capsulotomy size in the 2 laser groups. Both laser groups had better intraocular lens (IOL) centration than the manual group at all timepoints (P<.001). Between-group differences in uncorrected and corrected distance visual acuities were not statistically significant. The residual spherical equivalent and mean absolute error were statistically significantly smaller in the 2 laser groups than in the manual group (P=.038) and increased significantly over time in all the groups (P<.001).

CONCLUSIONS

Femtosecond laser capsulotomies showed better circularity with more predictable size than manual CCCs. In addition, IOL centration was better immediately after surgery and over time with better refractive results in the 2 laser groups.

Abstract B48: Preclinical development of meta-[211At] astatobenzylguanidine ([211At] MABG) targeted radiotherapy for neuroblastoma

Background: Neuroblastoma (NB) is a radiosensitive malignancy accounting for 10% of childhood cancer mortality. NB cells frequently express the norepinephrine transporter (NET) providing a specific mechanism for uptake of NET-ligands. Meta-[131I]iodobenzylguanidine ([131I]MIBG) is a NET-ligand radiotherapeutic that shows single-agent response rates in refractory NB of 40-50%. However, due to the long path lengths of 131 I beta (β)-emission, and low biological effectiveness compared to alpha (α)-emitting radionuclides, [131I]MIBG is generally not curative, perhaps due to non-targeting of isolated circulating tumor cells. Here we report our efforts to optimize NET-targeted radiotherapy by developing relevant preclinical models of refractory NB for α-particle therapeutic [211At] MABG therapy.

Methods: We first determined NET (SLC6A2) mRNA and protein expression in 35 human NB cell lines using quantitative RT-PCR and western blotting. We then chose 5 lines with absent to intermediate levels of native NET expression (NB1691, SKNSH, IMR5, NLF and SKNBE2) for dual forced overexpression of human NET and luciferase cDNAs. We used [125I]MIBG for cell-based uptake assays in all isogenic pairs and biodistribution experiments in athymic mice bearing three separate NET-transduced xenografts (N=5 per cell line). These cell lines were also treated with [131I]MIBG and/or external beam radiation (XRT) followed by multi-log cytotoxicity assays. Therapeutic trials of [131I]MIBG (25 mCi/kg) in NB1691 subcutaneous xenograft and metastatic mouse models were also conducted. In parallel, [211At] MABG was synthesized by: (i) cyclotron-production of 211 At via 209 Bi(α,2n)211At reaction (ii) distillation of 211 At from the target, and (iii) solid phase no-carrier-added synthesis of [211At] MABG by radioastato-destannylation. [211At] MABG uptake studies were performed in isogenic NB cell lines.

Results: Unlike primary human NBs, NET expression was low in the majority of 35 cell-lines studied (median normalized expression value = 0.145; range 0.000-1.005), but all transduced lines showed significant overexpression (0.860-1.107) comparable to human primary tumors. Transduced lines showed 4-10 fold higher uptake of [125I]MIBG than non-transduced isogenic parental cell lines in vitro, and demonstrated significant tumor-specific uptake and retention in vivo with tumor-muscle ratios ranging from 13.80 to 29.48. In vitro cytotoxicity experiments using [131I]MIBG showed NET-expressing cell lines to be more susceptible to treatment compared to non-NET expressing pairs (IC50 of 2.937nCi vs. 15.99 nCi). Treatment of mice bearing NB1691-NET xenografts with [131I]MIBG showed tumor growth delay (p=0.0065), but no significant impact on survival, likely due to de novo radioresistance (1200 cGy of XRT had no impact on NB1691 proliferation; IMR-05 showed 97% decreased cell viability). Lastly, we successfully synthesized [211At] MABG, with radiochemical yields of ∼20% and showed NET specific uptake of [211At] MABG into 1691 NET transfected cells.

Conclusions: Development of targeted radiotherapy for neuroblastoma has been limited by the lack of preclinical models and alternative therapeutics. Our development of multiple isogenic pairs with varying NET expression, documentation of de novo radiation sensitivity, and the production of [211At] MABG, will allow for rapid assessment of targeted radiotherapeutic strategies (including combination approaches) to support clinical development of alpha-particle therapeutics in a childhood cancer.

Citation Format: V Batra, AM Chacko, M Gagliardi, C Hou, J L. Mikitsh, R H. Freifelder, A Kachur, B C. LeGeyt, A Schmitz, L Toto, G Vaidyanathan, M R. Zalutsky, K K. Matthay, W A. Weiss, W C. Gustafson, D Pryma, J M. Maris. Preclinical development of meta-[211At] astatobenzylguanidine ([211At] MABG) targeted radiotherapy for neuroblastoma. [abstract]. In: Proceedings of the AACR Special Conference on Pediatric Cancer at the Crossroads: Translating Discovery into Improved Outcomes; Nov 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;74(20 Suppl):Abstract nr B48.

Reproducibility and repeatability of ganglion cell-inner plexiform layer thickness measurements in healthy subjects

PURPOSE

To assess the reproducibility and repeatability of macular ganglion cell-inner plexiform layer (GC-IPL) thickness measurements in healthy subjects.

PROCEDURES

In this observational study, 60 healthy eyes were subjected to macular GC-IPL thickness measurements by means of Cirrus™ high-definition optical coherence tomography (Cirrus version 6.0; Carl Zeiss Meditec, Dublin, Calif., USA) by two examiners in two sessions. Average, minimum and 6 sectoral GC-IPL thicknesses were measured. Inter- and intraobserver reproducibility was tested and analyzed by means of the concordance correlation coefficient (CCC). The repeatability of measurements was assessed by the coefficient of repeatability (CR).

RESULTS

Mean age (±SD) was 29.63 (±5.1) years. The CRs for average GC-IPL thickness were 2.1 and 2.2 µm for the first and the second operator, respectively. Inter- and intraobserver CCCs ranged from 0.91 (95% CI: 0.89-0.93) to 0.98 (95% CI: 0.96-0.99) and from 0.92 (95% CI: 0.88-0.94) to 0.98 (95% CI: 0.97-0.99), respectively.

CONCLUSIONS

GC-IPL thickness measurements in young healthy subjects showed excellent reproducibility and repeatability, especially for average and sectoral GC-IPL thickness measurements.

In vivo laser scanning confocal microscopy of the ocular surface in glaucoma

Over the past decade, knowledge about the ocular surface in glaucoma has significantly increased through the use of in vivo laser scanning confocal microscopy (LSCM). This in vivo imaging method can show modifications at the cellular level induced by anti-glaucoma drugs on ocular surface structures and adnexa in the eye. High-quality images of the conjunctiva, cornea, limbus, meibomian glands, and lymphoid structures during therapy can be obtained. In addition, LSCM opened new fields of research on the patho-physiology of aqueous humor (AH) hydrodynamics in untreated, and in medically or surgically treated glaucomatous patients. In these conditions, an enhancement of the trans-scleral AH outflow contributed to clarification of the mechanism of action of different anti-glaucoma medications and surgical approaches. Finally, the use of LSCM represented a huge advance in evaluation of bleb functionality after filtration surgery, defining the hallmarks of AH filtration through the bleb-wall and distinguishing functional from nonfunctional blebs. Thus, signs seen with LSCM may anticipate clinical failure, guiding the clinician in planning the appropriate timing of the various steps in bleb management. In this review we summarize the current knowledge about in vivo LSCM of the ocular surface in glaucoma.