Proliferative Vitreoretinopathy: A Reappraisal

Proliferative vitreoretinopathy (PVR) remains the main cause of failure after retinal detachment (RD) surgery. Despite the development of modern technologies and sophisticated techniques for the management of RD, the growth of fibrocellular membranes within the vitreous cavity and on both sides of the retinal surface, as well as intraretinal fibrosis, can compromise surgical outcomes. Since 1983, when the term PVR was coined by the Retina Society, a lot of knowledge has been obtained about the physiopathology and risk factors of PVR, but, despite the proposal of a lot of therapeutic challenges, surgical skills seem to be the only effective way to manage PVR complications.

MicroRNA Expression in Subretinal Fluid in Eyes Affected by Rhegmatogenous Retinal Detachment

Proliferative vitreoretinopathy (PVR) is an abnormal intraocular scarring process that can complicate cases of rhegmatogenous retinal detachment (RRD). Although previous studies have examined the relevance of microRNAs (miRNAs) in ophthalmic diseases, only a few studies have evaluated the expression profiles of microRNAs in subretinal fluid. We hypothesized that the expression profiles of specific miRNAs may change in response to RRD, in the subretinal fluid that is directly in contact with photoreceptors and the retinal pigment epithelium (RPE). We looked for a potential correlation between the expression of specific miRNAs in eyes with RRD and known clinical risk factors of PVR. A total of 24 patients (59 ± 11 years) who underwent scleral buckling procedure were enrolled in this prospective study. Twenty-four undiluted subretinal fluid samples were collected, RNA was isolated and qRT-PCR was performed to analyze the expression of 12 miRNAs. We found the existence of a positive association between the expression of miR-21 (p = 0.017, r = 0.515) and miR-34 (p = 0.030, r = 0.624) and the duration of symptoms related to retinal detachment. Moreover, the expression of miR-146a tended to decrease in patients who developed PVR. Subretinal fluid constitutes an intriguing biological matrix to evaluate the role of miRNAs leading to the development of PVR.

Scleral and conjunctival features in patients with rhegmatogenous retinal detachment undergoing scleral buckling: an anterior segment optical coherence tomography and in vivo confocal microscopy study

PURPOSE

To investigate the scleral and conjunctival features in patients with rhegmatogenous retinal detachment (RRD) undergoing scleral buckling (SB), using anterior segment optical coherence tomography (AS-OCT) and in vivo confocal microscopy (IVCM).

METHODS

Twenty RRD eyes were consecutively enrolled. AS-OCT was performed at RRD diagnosis (RRD-D) and day 1, week 1, month 1 and month 6 after SB to evaluate the sclera, in the affected and unaffected quadrants (AQ, UQ). IVCM was performed at RRD-D, and at month 1 and month 6, to evaluate the conjunctiva in AQ and UQ. The main outcomes were as follows: mean intra-scleral hypo-reflective spaces area (MIHSA) at AS-OCT; mean density and area of microcysts (MMD, MMA) at IVCM; and intra-ocular pressure (IOP). The relations between MIHSA, MMA, MMD and IOP were evaluated.

RESULTS

Rhegmatogenous retinal detachment- diagnosis (RRD-D) overall-mean intra-scleral hypo-reflective spaces (MISHA), -MMD and -MMA were significantly higher in affected eye (AE) compared with UE (p < 0.05) and in AQ compared with UQ (p < 0.05). After SB, overall-, AQ- and UQ-MISHA further increased (p < 0.05), whereas overall-MMD and -MMA did not change. At all follow-up, AQ and UQ parameters did not show significant differences between them. RRD-D IOP was 14.3 ± 2.8 and 15.5 ± 2.7 mmHg in the AE and UE, respectively (p < 0.05). After SB, week-1, month-1 and -6 IOP was significantly lower than RRD-D (p < 0.05). Rhegmatogenous retinal detachment- diagnosis (RRD-D), 1- and 6-month overall and AQ-MISHA and AQ-MMD negatively correlated with IOP (p < 0.05).

CONCLUSION

Rhegmatogenous retinal detachment (RRD) and SB induced scleral and conjunctival changes that suggested an activation of fluid outflow through the entire unconventional aqueous humour pathway; these modifications may in part account for the relative hypotony after RRD and SB.

Early retinal flow changes after vitreoretinal surgery in idiopathic epiretinal membrane using swept source optical coherence tomography angiography

(1) Background: The aim of this observational cross-sectional work was to investigate early retinal vascular changes in patients undergoing idiopathic epiretinal membrane (iERM) surgery using swept source optical coherence tomography angiography (SS-OCTA); (2) Methods: 24 eyes of 24 patients who underwent vitrectomy with internal limiting membrane (ILM) peeling were evaluated pre- and postoperatively using SS-OCTA system (PLEX Elite 9000, Carl Zeiss Meditec Inc., Dublin, CA, USA). For each eye, five 6x6-mm OCTA volume scans were acquired by two observers independently. The en face images of superficial capillary plexus (SCP) were then exported to imageJ and a semi-automated algorithm was used for subsequent quantitative analysis. Perfusion density (PD), vessel length density (VLD), vessel diameter index (VDI) and vessel tortuosity (VT) of SCP were evaluated in both the parafoveal (2.5 mm diameter) and perifoveal areas (5.5 mm diameter); (3) Results: At OCTA analysis statistically significant differences were found between controls and diseased eyes for all parameters in parafoveal and perifoveal regions (p < 0.001; p < 0.05) except for perifoveal VLD. During 6-month follow up, both anatomical/perfusion and functional parameters showed a statistically significant improvement if compared to preoperative values. In detail, at one-month post vitrectomy, VLD and VT significantly changed in parafoveal region (p = 0.043; p = 0.045), while PD and VDI showed a trend of increase in both parafoveal and perifoveal region. At 6 months after surgery, PD, VLD and VT of parafoveal region significantly improved (p = 0.021, p = 0.018, p = 0.047 respectively). (4) Conclusions: SS-OCTA provides a quantitative and qualitative analysis of the superficial capillary plexus allowing for early vascular changes assessment after vitrectomy with iERM and ILM peeling.

Correlation between Choriocapillaris Density and Retinal Sensitivity in Stargardt Disease

The aim of this work was to characterize the choriocapillaris (CC) in patients with Stargardt disease (STGD) using the swept source widefield optical coherence tomography angiography (SS WF OCTA) and to compare CC perfusion density to retinal sensitivity, analyzed using microperimetry (MP). This cross-sectional study included 9 patients (18 eyes) with STGD and central CC atrophy (stage 3 STGD). The CC was analyzed using SS WF OCTA and areas of different CC impairment were quantified and correlated with retinal sensitivity analyzed using MP. The main outcome measures were the percent perfused choriocapillaris area (PPCA), retinal sensitivity, and correlation between PPCA and retinal sensitivity. Seventeen eyes of 9 patients suffering from stage 3 STGD were analyzed. SS WF OCTA revealed a vascular rarefaction in central atrophic zones and a near atrophy halo of choriocapillaris impairment. In all eyes were noticed a central atrophy (CA) area with absolute absence of CC that corresponded to 0 dB points at MP, a near atrophy (NA) zone of PPCA impairment that included points with decreased sensitivity at MP and a distant from atrophy (DA) zone with higher PPCA and retinal sensitivity values. The mean difference of PPCA and retinal sensitivity between NA and CA and DA and CA was statistical significantly different (p < 0.01), the latter showing higher values. A direct relationship between PPCA and retinal sensitivity was found (p < 0.001). Choriocapillaris damage evaluated using SS WF OCTA correlates with MP, these data suggest that CC impairment may be a predictor of retinal function in patients with STGD.

Intraoperative optical coherence tomography in the full-thickness macular hole surgery with internal limiting membrane inverted flap placement

PURPOSE

To describe the helpfulness of using intraoperative optical coherence tomography (OCT) during surgery for full-thickness macular hole (FTMH).

OBSERVATIONS

This observational case series identifies three patients with FTMH who were treated with vitrectomy, internal limiting membrane (ILM) peel with inverted ILM flap, which was tucked into the MH, and air with 18% Sulfur Hexafluoride (SF₆) gas tamponade. Intraoperative OCT was used to confirm positioning of the ILM flap, even after complete air-fluid exchange. The patients were followed for three months after surgery and all reached a good morphological and functional outcome.

CONCLUSIONS

If confirmed by a prospective longitudinal study, the intraoperative OCT might become an important tool in assisting FTMH surgery.

Optical Coherence Tomography and Retinal Thickness Analyzer Features of Spontaneous Resolution of Vitreomacular Traction Syndrome: A Case Report

Purpose

To report optical coherence tomography (OCT) and retinal thickness analyzer (RIA) findings in a case of spontaneous resolution of vitreomacular traction syndrome.

METHODS

Qualitative and quantitative analysis of the macular region was performed with OCT and RTA.

Results

In the left eye of a 34-year-old woman with blurred vision, OCT and RTA examination showed a discrete linear signal anterior to the retina with attachment at the macula and secondary cystoid macular changes. OCT and RTA examination showed an increase in macular thickness (350 μm). Six months later the patient showed a spontaneous complete recovery of visual acuity. Vitreomacular traction and cystoid changes were no longer detectable at OCT and RTA examination; retinal thickness was normal (205 μm) and a posterior vitreous detachment was visible.

CONCLUSIONS

Both OCT and RTA were useful tools for making the diagnosis of vitreomacular traction syndrome and demonstrating the effect of spontaneous vitreomacular traction release with resolution of cystoid macular changes.

Optical Coherence Tomography Imaging of Surgical Resolution of Bilateral Vitreomacular Traction Syndrome Related to Incomplete Posterior Vitreoschisis: A Case Report

Purpose

To report a case of surgical resolution of bilateral vitreomacular traction syndrome related to incomplete posterior vitreoschisis as documented by optical coherence tomography (Stratus OCT, Carl Zeiss Meditec, Dublin, CA).

Case Report

In both eyes of a 72-year-old man with bilateral blurred vision, OCT examination disclosed a relevant increase in mean foveal thickness (right eye = 714 μm; left eye = 757 μm) due to a vitreomacular traction syndrome. At the edges of the most highly elevated area of vitreo-macular traction, OCT scans showed a characteristic splitting of the hyperreflective signal in both eyes, usually identified as posterior vitreous cortex. Both eyes underwent vitrectomy with epiretinal membrane peeling. Postoperative OCT examination showed vitreomacular traction resolution in both eyes with an evident decrease in mean foveal thickness (right eye = 364 μm; left eye = 335 μm). Right visual acuity improved from 20/200 to 20/50; left visual acuity changed from 20/150 to 20/40.

Conclusions

OCT was a useful tool in identifying an unusual case of bilateral vitreomacular traction syndrome linked to incomplete posterior vitreoschisis and following a favorable course after surgical management.

Optical Coherence Tomography Findings of Incomplete Posterior Vitreoschisis with Vitreomacular Traction Syndrome and Impending Macular Hole: A Case Report

Purpose

Vitreomacular traction syndrome is a clinical entity characterized by partial posterior vitreous detachment in combination with persistent macular adherence. Recently, optical coherence tomography (OCT) allowed visualization of incomplete posterior vitreoschisis leading to vitreomacular traction.

Methods

The authors report on a 57-year-old woman with blurred vision in her left eye.

Results

OCT scan showed incomplete posterior vitreoschisis with vitreomacular traction syndrome and impending macular hole in her left eye.

Conclusions

The intraoperative findings together with the evidence that the internal limiting membrane (ILM) thickness is thinner than the axial resolution of the Stratus OCT (8 μm) and a spontaneous ILM detachment has never been demonstrated are likely to support the hypothesis that posterior vitreoschisis exists and can be associated with vitreomacular traction syndrome.

Optical Coherence Tomography and Fundus Microperimetry Imaging of Spontaneous Closure of Traumatic Macular Hole: A Case Report

PURPOSE

To report a case of spontaneous closure of traumatic macular hole in a young patient followed using optical coherence tomography (OCT) and fundus microperimetry.

METHODS/RESULTS

In the right eye of a 10-year-old child, a traumatic macular hole was observed to spontaneously resolve 18 weeks after blunt trauma. Initially, visual acuity in the right eye was 20/200 and OCT examination showed a 200 microm-diameter full-thickness macular hole with perifoveal edema. Fundus microperimetry examination showed an evident decrease in retinal sensitivity within the macular hole and in the upper macular region where an area of commotio retinae was clearly visible. During follow-up OCT demonstrated the appearance of a band of tissue linking the inferior edge of the hole to the foveal retinal pigment epithelium and at the bottom of the hole the presence of hyperreflective (glial) material. Eighteen weeks after trauma right eye visual acuity had improved to 20/25, OCT examination showed a restored foveal depression, and fundus microperimetry demonstrated an increase in foveal sensitivity.

CONCLUSIONS

Both OCT and fundus microperimetry were useful tools for following the favorable course in a case of spontaneous closure of traumatic macular hole in a young patient. During follow-up OCT examinations were able to demonstrate the course of macular hole closure.

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.

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.

Subretinal Fluid Levels of Signal-Transduction Proteins and Apoptosis Molecules in Macula-Off Retinal Detachment Undergoing Scleral Buckle Surgery

Purpose

To evaluate signal transduction and early apoptosis protein levels in subretinal fluid collected during scleral buckling surgery for macula-off rhegmatogenous retinal detachment (RRD). Our aim was to assess both their relation with RRD features and their influence on the posttreatment outcome.

Methods

Thirty-three eyes of 33 RRD patients scheduled for scleral buckle surgery were enrolled in the study. Undiluted subretinal fluid samples were collected during surgery and analyzed via magnetic bead-based immunoassay. All patients underwent a complete ophthalmologic evaluation at baseline and at each follow-up visit (months 1, 3, and 6). Moreover, both at baseline and at the postsurgery month 6 visit, the patients were tested by means of spectral-domain optical coherence tomography (SD-OCT) in order to evaluate the average ganglion cell-inner plexiform complex thickness, as well as the photoreceptor inner segment/outer segment junction status.

Results

Patients' clinical features (retinal detachment size, detachment duration, and occurrence of proliferative vitreoretinopathy) were associated with several early apoptotic factors (caspase-8, caspase-9, and B-cell lymphoma 2 [Bcl-2]-associated death promoter [BAD]). Furthermore, both early apoptosis factors (caspase-8, Bcl-2, and p53) and signal-transduction proteins (ERK 1/2) were found to influence the postsurgery month 3 OCT characteristics.

Conclusions

Signal-transduction proteins and early apoptosis proteins are associated with different clinical features and postsurgery outcomes.

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.

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.

Spectral domain optical coherence tomography and in vivo confocal microscopy imaging of a case of Bietti's crystalline dystrophy

BACKGROUND

The aim was to describe the morphology and localisation of crystals in a case of Bietti's crystalline corneo-retinal dystrophy (BCD) by means of spectral domain optical coherence tomography (SD-OCT) and in vivo confocal microscopy (IVCM).

METHODS

Clinical examination, SD-OCT and IVCM evaluation of a 35-year-old woman with BCD.

RESULTS

Optical coherence tomography examination of the macular region revealed multiple crystals in the retinal pigment epithelium (RPE)-choriocapillaris, some crystals within the full thickness of the neurosensory retina and less numerous crystals in the choroid. Crystals were present peripherally in areas of retinal atrophy, predominantly in the choroid and to a lesser extent in the RPE-choriocapillaris and the neuroepithelium. In vivo confocal microscopy showed multiple crystals of varying morphology in the peripheral and paralimbal cornea, mainly located in the anterior stroma over 360°.

CONCLUSIONS

SD-OCT provided greater precision in the localisation of crystals, found mainly in the choroid and RPE-choriocapillaris rather than the neuroepithelium. In vivo confocal microscopy revealed a higher number of crystals compared to those visible using conventional slitlamp biomicroscopy and showed a different crystal morphology.

Conjunctival findings in hyperbaric and low-tension glaucoma: an in vivo confocal microscopy study

PURPOSE

To analyse the epithelial features of the bulbar conjunctiva in hyperbaric and low-tension glaucoma (LTG) using in vivo confocal microscopy (IVCM).

METHODS

Thirty-six eyes of 36 patients [18 affected by primary open-angle glaucoma (POAG) and 18 with LTG] were studied; control group was constituted by 28 eyes of 28 healthy subjects. All eyes were examined using digital confocal laser-scanning microscopy (HRT II Rostock Cornea Module). The main IVCM outcome measurements were mean density (MMD: cysts/mm(2)) and mean total area (MMA: μm(2)) of the epithelial microcysts.

RESULTS

The mean intraocular pressure level (mmHg ± SD) was 15.1 ± 1.7, 16.3 ± 3.1 and 12.6 ± 1.8 in healthy, POAG and LTG eyes, respectively. Conjunctival microcysts were found in all patients and subjects: for healthy subjects, MMD = 10.9 ± 11.1 cysts/mm(2) and MMA = 1501.9 ± 1191.1 μm(2); for patients infected with POAG, MMD = 36.8 ± 28.6 cysts/mm(2) and MMA = 7904.8 ± 7050.5 μm(2); and for patients infected with LTG MMD = 45.6 ± 29.0 cysts/mm(2) and MMA =7946.9 ± 5227.5 μm(2). MMD and MMA were not significantly different between patients infected with POAG and those with LTG, whereas they were significantly greater in patients (fourfold and fivefold, respectively) than healthy subjects.

CONCLUSIONS

The present study demonstrated that conjunctival microcysts represent an in vivo feature in all eyes with medically controlled POAG and LTG. Therefore, conjunctiva deserves careful analysis, because its accurate microscopic definition could help clarify the pathophysiology of aqueous outflow in glaucoma.

Reproducibility and repeatability of Cirrus™ HD-OCT peripapillary retinal nerve fibre layer thickness measurements in young normal subjects

PURPOSE

To assess the reproducibility and repeatability of peripapillary retinal nerve fibre layer (RNFL) thickness measurements using a spectral-domain optical coherence tomography (SD-OCT) device in healthy subjects.

METHODS

In this observational study, 68 young Caucasian healthy volunteers (68 eyes) were subjected to Cirrus™ high-definition (HD) OCT (Zeiss) peripapillary RNFL thickness measurements by two experienced examiners in two different sessions. Average, 4-quadrant and 12-clock-hour sector RNFL thicknesses were analysed. For each option, intra-observer, intrasession repeatability and interobserver, intersession reproducibility were tested. To assess the repeatability of measurements, the Bland and Altman plots were used and the coefficient of repeatability was calculated. Interobserver and intersession reproducibilities were analysed by means of concordance correlation coefficients (CCCs).

RESULTS

The sample age ranged from 21 to 39 years (mean 29.09, standard deviation ±5.21). The average RNFL thickness ranged from 90.97 to 91.46 and from 91.34 to 91.78 μm, for the first and the second operator, respectively. The highest repeatability and reproducibility were obtained for average RNFL thickness with coefficients of repeatability of 5.30 and 6.05 μm for the first and the second operator, interoperator CCCs of 0.95 and 0.96 for the first and the second session, and intersession CCCs of 0.96 and 0.97 for the first and the second operator, respectively.

CONCLUSIONS

Cirrus OCT peripapillary average RNFL thickness measurement in young healthy subjects showed high interoperator and intersession reproducibility. Intrasession repeatability as tested by coefficient of repeatability was next to the device resolution, with very similar results between the two operators. When analysing quadrant and clock hour sector RNFL thickness measurements, both repeatability and reproducibility tend to decrease.

Conjunctival and corneal findings in bleb-associated endophthalmitis: an in vivo confocal microscopy study

PURPOSE

To report the conjunctival and corneal findings in delayed onset glaucoma filtering bleb-associated endophthalmitis (BAE), by using in vivo confocal microscopy (IVCM).

METHODS

This was an observational case series. Four eyes of four glaucomatous patients who previously underwent mytomicin C augmented filtering surgery and affected with delayed onset BAE, underwent IVCM of conjunctival bleb and cornea at diagnosis, after 2 and 8 weeks of therapy. The inflammatory status of the conjunctival epithelium and sub-epithelium was microscopically investigated. Corneal epithelial cells, stromal and endothelial morphology were also evaluated. A group of eight patients with functioning conjunctival filtering bleb was used as control.

RESULTS

At diagnosis, a diffuse inflammatory cell infiltration within the conjunctival epithelium presenting evident microcysts was found; conversely, there were no such alterations in the sub-epithelium. An evident stromal oedema, keratocytes activation and diffuse endothelial inflammatory precipitates were the major corneal hallmarks. After 2 weeks of therapy, besides a remarkable improvement of epithelial inflammation and an evident reduction in endothelial precipitates, dendritic cells appeared within conjunctival sub-epithelium and corneal epithelium showed aspects of cellular disruption. After 8 weeks, the conjunctival and corneal features consistently improved, except for the endothelium which still presented high-reflective residual precipitates.

CONCLUSIONS

In vivo confocal microscopy proved valuable in the analysis of conjunctival bleb and cornea in patients affected with delayed onset BAE, permitting an evaluation of the course of the disease, the response to therapy and the modulation of dose regimen.

The role of diagnostic imaging techniques in the management of retinal detachment due to macular hole in high myopia

After preoperative assessment revealed anomalous posterior vitreous detachment, a 75-year-old woman affected with retinal detachment due to macular hole was scheduled to undergo the posterior episcleral buckling procedure. Preoperative microperimetry showed unstable eccentric fixation with a dense scotoma within the central 8 degrees. One month postoperatively, best-corrected visual acuity increased from 1.70 to 0.88 logarithm of the minimum angle of resolution. Ultrasonography and optical coherence tomography revealed the indentation of the posterior scleral profile due to the buckle. The retina appeared fully attached and a macular hole with flattened edges was still detectable. Microperimetry showed stable central fixation with recovery of retinal sensitivity within the central 2 degrees. Diagnostic imaging techniques guided the decision to use the posterior episcleral buckling procedure. Microperimetry was useful to explain vision improvement despite residual macular hole.

OCT imaging of capsular block syndrome with crystalline cortical remnants in the capsular bag

A 72-year-old woman with cataract had phacoemulsification and intraocular lens implantation in the capsular bag with continuous curvilinear capsulorrhexis in the right eye. One day postoperatively, cortical remnants were noted between the posterior capsule and the intraocular lens optic located inferiorly. Uncorrected visual acuity was 1.0 and the patient was emmetropic. At a control visit 6 years postoperatively, the patient showed a hyperopic shift compared with the refraction of the first postoperative period with a best-corrected visual acuity of 0.4. A transparent liquefied substance that accumulated between the lens optic and the fibrotic capsule and surrounding the residual cortical masses was clearly visible using slit-lamp biomicroscopy and anterior segment optical coherence tomography. A surgical revision with aspiration of the cortical masses and the fluid was performed, resolving the capsular block syndrome. A neodymium:YAG laser posterior capsulotomy followed to clear the visual axis.

A 12-week Study Evaluating the Efficacy of Bimatoprost 0.03% in Patients with Pseudoexfoliative and Open-Angle Glaucoma

Purpose

To evaluate the control of diurnal intraocular pressure (IOP) and the safety profile of bimatoprost in pseudoexfoliative glaucoma (PXG) compared to primary open angle glaucoma (POAG).

Methods

A prospective, observer-masked, nonrandomized study was performed. Seventy consecutive patients with either POAG (35 eyes) or PXG (35 eyes) drug-naive for glaucoma were assigned to receive bimatoprost 0.03% once daily for 12 weeks. Diurnal IOP was measured at baseline and after 12 weeks at three time points (8 AM, noon, and 4 PM). Main outcomes were diurnal IOP control and achievement of target IOP (CIGTS criteria). Mean diurnal IOP, hour-by-hour IOP measurements, and safety, including serious adverse events, were also evaluated.

Results

A significant IOP reduction from baseline was found in both groups (p<0.001). Mean and hour-by-hour IOP differences between groups were not statistically significant (NS). The observed IOP values and percentages of IOP reduction were 17.0 mmHg (31.5%) and 16.4 mmHg (31.9%) in PXG and POAG eyes, respectively; the differences were not statistically significant. Six eyes (1 POAG and 5 PXG, respectively) responded with a <20% IOP reduction (NS). Twenty-seven POAG (77.1%) and 23 PXG (65.7%) eyes achieved target IOP. Consequently, 20 eyes (8 POAG and 12 PXG, respectively) were classified as unable to achieve the IOP target values (NS).

Conclusions

Bimatoprost was effective and safe in lowering IOP both in open angle and pseudoexfoliative glaucoma, achieving target pressure in most patients. However, long-term efficacy in PXG must be evaluated.

Correlation in foveal thickness measurements between spectral-domain and time-domain optical coherence tomography in normal individuals

PURPOSE

To compare a time-domain (Stratus) and a spectral-domain (Spectralis) optical coherence tomography (OCT) device in assessing foveal thickness in healthy subjects.

METHODS

In this observational study 40 healthy subjects (40 eyes) underwent Stratus OCT and Spectralis OCT measurements of foveal thickness using three consecutive horizontal and vertical B-scan. Paired samples t-test was used to compare means between Stratus and Spectralis OCT measurements. Coefficient of variation (CoV) was used to compare dispersion in datasets. Pearson's correlation coefficient was used to quantify linear relation between Spectralis and Stratus OCT measurements. To assess agreement between Spectralis and Stratus OCT foveal thickness measurements, the Bland and Altman plots were used.

RESULTS

Sample age ranged from 19 to 49 years (mean 33.25, standard deviation (SD) +/-4.22). The Spectralis OCT foveal thickness measurements resulted significantly higher than those obtained with Stratus OCT (227.64+/-11.74 vs 144.36+/-12.25 microm, and 227.63+/-11.43 vs 144.92+/-12.34 microm, for horizontal and vertical foveal thickness, respectively) (P<0.05). Coefficient of variations were 5.16 and 5.02% using Spectralis OCT, and 8.49 and 8.51% using Stratus OCT. Mean Spectralis/Stratus ratio was 1.58 for both horizontal and vertical measurements. A linear relation between the two technologies was found (r(horiz)=0.899 and r(vert)=0.869) (P<0.001).

CONCLUSIONS

A good correlation between Stratus and Spectralis OCT foveal measurements was found, independently of retinal thickness. This preliminary study suggests the existence of a conversion factor between Stratus and Spectralis OCT when measuring healthy foveal thickness.

Femtosecond laser arcuate keratotomy for the correction of high astigmatism after keratoplasty

PURPOSE

To determine the feasibility and initial outcomes of using a femtosecond laser to perform arcuate keratotomies to correct high post-keratoplasty astigmatism.

DESIGN

Prospective noncomparative interventional case series.

PARTICIPANTS

Twelve eyes of 12 consecutive patients (mean age 44.9+/-9.5 years) who presented with a high degree of astigmatism, noncorrectable with spectacles or contact lenses (10 post-penetrating keratoplasty, 2 post-deep lamellar keratoplasty), and were candidates for relaxing incisional corneal surgery.

METHODS

The Femtec (20/10 Perfect Vision, GmbH, Heidelberg, Germany) femtosecond laser performed paired 90-degree angled arcuate incisions on the graft button. The incision sites and depths were programmed at 1.00 mm inside the graft edge and at 90% of the corresponding local graft thickness, whereas the angular lengths of the cuts were determined by analyzing the locations and extents of the steepest meridians in the topographic map.

MAIN OUTCOME MEASURES

Changes in uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), mean subjective and topographically determined astigmatism; imaging of incisions by anterior segment optical coherence tomography (AS-OCT); and wound healing by in vivo confocal microscopy (IVCM).

RESULTS

Postoperative follow-up extended to 6 months. Mean uncorrected logarithm of the minimum angle of resolution (logMAR) BSCVA and UCVA improved from preoperative values of 0.25+/-0.16 and 1.05+/-0.18 to 6-month values of 0.11+/-0.12 (standard deviation) and 0.55+/-0.34, respectively (P<0.05). Mean subjective astigmatism was 7.16+/-3.07 diopters (D) preoperatively and 2.23+/-1.55 D at 1 month after surgery (P = 0.002) and remained stable to the end of follow-up. Anterior segment optical coherence tomography image analysis showed that the depth and location of the incisions were consistent with the preoperative surgical plan. In vivo confocal microscopy showed mild edema and keratocyte activation along the incision edges, together with initial epithelial ingrowth inside the wound, followed by subsequent moderate fibrotic scarring.

CONCLUSIONS

Arcuate keratotomies performed with the femtosecond laser were effective in reducing post-keratoplasty astigmatism. Laser-generated incisions within the graft button presented precise geometry and reliable depth of incision, with a wound healing pattern characterized by epithelial ingrowth and mild fibrosis.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

An in vivo confocal microscopy and impression cytology analysis of preserved and unpreserved levobunolol-induced conjunctival changes

PURPOSE

To provide an in vivo confocal microscopy (IVCM) and impression cytology analysis of preserved-and unpreserved levobunolol-induced changes of conjunctival epithelium.

METHODS

27 eyes of 27 patients were consecutively randomized to receive preserved or unpreserved levobunolol; all patients had a recent diagnosis of primary open angle glaucoma (POAG) or ocular hypertension and were not previously treated with topical medications. IVCM and impression cytology were performed before and after six months of therapy. Goblet cells density and a conjunctival epithelium regularity index were considered in the IVCM analysis, whereas impression cytology specimens were graded and scored in accordance with Nelson's method.

RESULTS

After six months of therapy, IVCM and impression cytology parameters showed significant differences with respect to baseline in both groups (p<0.001); significant differences were also found between the two groups (p<0.001). The IVCM analysis showed a goblet cells density reduction (61% and 17% from baseline, respectively in group 1 and 2) (p<0.001) and an higher index of epithelial regularity (p<0.001) in both groups; the impression cytology analysis showed an higher score in both groups (p<0.001).

CONCLUSIONS

All the IVCM and impression cytology parameters correlated well with the conjunctival modifications induced by the topical therapy, suggesting the less toxicity of unpreserved drugs.

Fixation patterns evaluation by means of MP-1 microperimeter in microstrabismic children treated for unilateral amblyopia

PURPOSE

The aim of the study was to evaluate the fixation patterns of microstrabismic children previously treated for unilateral amblyopia.

METHODS

Thirty-three children (mean age 7.3+/-1.5 years) were included in the study. Visual acuity (VA) was measured using the Early Treatment of Diabetic Retinopathy Study charts. Fixationwas assessed by MP-1 microperimeter. Differences in position and stability of fixation between the fellow and the microstrabismic eyes were calculated by using the percentage of the preferred fixation points within central fixation and the percentage of the fixation points within target fixation, respectively. For statistical analysis Mann-Whitney test was used. To evaluate the influence of age and duration of anti-amblyopic treatment on microstrabismic eyes fixation, linear regression analysis was performed.

RESULTS

In the microstrabismic eyes VA was significantly reduced when compared to the fellow eyes (0.1236+/-0.0204 vs 0.0042+/-0.0032 logMAR; p<0.001). Position and stability of fixation were significantly better in the fellow eyes (93.21+/-0.65% vs 70.91+/-4.80%; p=0.002, and 89.88+/-0.94% vs 71.73+/-2.94%; p<0.001, respectively). A significant correlation was found between fixation stability and both the duration of anti-amblyopic treatment and pretreatment VA (p=0.024 and p=0.009, respectively) and between fixation centrality and pretreatment VA (p<0.001).

CONCLUSIONS

VA, centrality, and stability of fixation were significantly impaired in the microstrabismic eyes. Pretreatment VA was a risk factor for fixation impairment. The severity of fixation stability impairment was linked to the duration of anti-amblyopic treatment.

Multilayer amniotic membrane transplantation for bacterial keratitis with corneal perforation after hyperopic photorefractive keratectomy

We report a case of corneal infection caused by Streptococcus pneumoniae after hyperopic photorefractive keratectomy (PRK) that produced severe corneal melting, ulceration, and multiple perforations. Treatment included antibiogram-based antibiotic topical therapy and multilayer amniotic membrane transplantation (AMT) performed to seal the perforations and restore the globe integrity. Clinical and anterior segment optical coherence tomography (Visante OCT, Carl Zeiss Meditec) examinations documented progressive integration of the amniotic membrane tissues within the cornea, stromal and epithelial healing, and recovery of a stable and regular anterior chamber. The cornea healed with an avascular leucoma; the best corrected visual acuity was reduced to 20/200. Severe pneumococcal ulcerative perforation is a potential complication of PRK. Penetrating keratoplasty, at high risk for failure in the acute settings of an infected and inflamed eye, can be delayed until the cornea is healed. Amniotic membrane transplantation may be an alternative surgical option to achieve this goal.

Amniotic membrane transplantation for the management of corneal epithelial defects: an in vivo confocal microscopic study

PURPOSE

To evaluate amniotic membrane (AM) tissue morphology and corneal epithelial healing in human eyes after amniotic membrane transplantation (AMT), using laser scanning in vivo confocal microscopy (IVCM).

PATIENTS AND METHODS

Twenty eyes of 20 patients, treated with single layer epithelial side up AMT for chemical burns in the acute stage (n = 8) and persistent corneal epithelial defect (n = 12) were studied by serial IVCM post-AMT until complete re-epithelisation. Changes in morphology of transplanted amniotic tissue and healing corneal epithelium were noted. AM and corneal epithelial cell density was calculated using image-analysis software.

RESULTS

IVCM enabled visualisation of transplanted AM and of regenerating epithelial cells under the AM. The mean AM epithelial cell density, 1 day after transplant, was 4613 (SD 380) cells/mm2. The average AM epithelial thickness was 35 (4) microm, while the AM stromal thickness was 116 (31) microm. The amniotic stroma appeared to be composed of a superficial dense fibrous layer and a deeper loose reticular network of fibres. Amniotic epithelium was lost within 15 days of transplant, and complete re-epithelisation of the corneal surface was achieved between 1 and 4 weeks.

CONCLUSIONS

Laser scanning IVCM is a useful method for evaluating AM tissue morphology, degradation and corneal epithelial healing after AMT for different clinical indications. When the amniotic membrane acts as a patch, that is epithelial cells migrate under rather than over the membrane, the membrane disintegrates and is lost.

Longterm results of 1 CU® accommodative intraocular lens implantation: 2-year follow-up study

PURPOSE

To evaluate the longterm efficacy of 1 CU accommodative intraocular lenses (IOLs) to restore near visual performance.

METHODS

This prospective study comprised 14 eyes previously included in a 6-month, case-control clinical trial, undergoing phacoemulsification and implantation of a 1 CU accommodative IOL. The main outcome measures were subjective refraction, uncorrected distance visual acuity (UCDVA), best corrected distance VA (BCDVA), distance-corrected near VA (DCNVA), best corrected near VA (BCNVA), and subjective amplitude of accommodation (AA). In addition, anterior and posterior capsule opacification were assessed. Patients were examined over a 2-year follow-up period.

RESULTS

Distance and near visual performance worsened after 6 months. Uncorrected DVA and BCDVA were 0.8 +/- 2.1 and 1.0 +/- 0.8 at 6 months and 0.4 +/- 0.1 and 0.6 +/- 0.1 at 1 year, respectively (p = 0.001). Distance-corrected NVA and BCNVA were 3.7 +/- 2.1 Jaeger (J) and 1.0 +/- 0.7 J at 6 months and 8.1 +/- 0.7 J and 1.5 +/- 0.5 J at 1 year, respectively (p = 0.001). Anterior and posterior capsule opacification were present, respectively, in 28% and 21% of patients at 6 months and in 100% of patients at 1 and 2 years (p < 0.001). After Nd:YAG laser capsulotomy (performed in 100% of patients), UCDVA and BCDVA increased to 0.7 +/- 0.2 (p = 0.007) and 1.0 +/- 0.1 (p = 0.001), respectively, at 2 years. Distance-corrected NVA improved to 7.3 +/- 0.5 J (p = 0.006). Mean AA was 1.9 +/- 0.8 D at 6 months, 0.3 +/- 0.2 D (p = 0.004) at 1 year and 0.3 +/- 0.2 D at 2 years.

CONCLUSIONS

Patients implanted with 1 CU IOLs lost their accommodation capacities with time because of the high incidence and degree of anterior and posterior capsule opacification. The accommodative lens material and design may have played a role in capsule fibrosis.

FUNDUS MICROPERIMETRY PATTERNS OF FIXATION IN TYPE 2 DIABETIC PATIENTS WITH DIFFUSE MACULAR EDEMA

BACKGROUND

Recently developed fundus microperimetry (MP-1; Nidek Technologies, Srl. Vigonza PD, Italy) was used to evaluate fixation patterns and retinal sensitivity in patients who had clinically significant macular edema with a diffuse pattern and type 2 diabetes mellitus.

METHODS

In a prospective, observational case series study, 84 consecutive patients with type 2 diabetes (84 eyes) who had clinically significant macular edema with a diffuse pattern were studied by means of MP-1. Main outcome measures were fixation stability and position and mean retinal sensitivities within the central 2 degrees and 8 degrees areas. Logarithm of the minimum angle of resolution (logMAR) best-corrected visual acuity (BCVA) was evaluated by means of an Early Treatment of Diabetic Retinopathy Study chart. Foveal thickness was measured by Stratus optical coherence tomography (OCT; Carl Zeiss Meditec, Inc., Dublin, CA). Age, duration of diabetes, hemoglobin A1c (HbA1c) levels, duration of symptoms, history of panretinal photocoagulation, vitreomacular adhesion, and cystoid macular changes were documented. Patients were grouped according to both position of fixation (central or eccentric) and stability of fixation (stable or unstable). Statistical analyses included independent samples t-test, binomial test, Bonferroni correction for multiple comparisons, and generalized linear model univariate analysis.

RESULTS

Of 84 eyes, 44 (52.4%) had central fixation, and 40 (47.6%) had eccentric fixation. Of 84 eyes, 34 (40.5%) had stable fixation, and 50 (59.5%) had unstable fixation. In the whole sample, mean central 2 degrees retinal sensitivity +/- SD was 6.26 +/- 3.19 dB (range, 0-14.80 dB), and mean central 8 degrees retinal sensitivity +/- SD was 7.62 +/- 2.55 (range, 3.85-14.90 dB); logMAR BCVA ranged from 0.1 to 1.3 (mean +/- SD, 0.6 +/- 0.29). Mean OCT foveal thickness +/- SD was 300.77 +/- 66.93 m (range, 220-525 m). Both comparisons between groups (stable vs. unstable and central vs. eccentric) showed statistically significant differences in mean logMAR BCVA, mean central 2 degrees and 8 degrees retinal sensitivities, and mean OCT foveal thickness. Duration of symptoms was significantly longer and HbA1c levels were higher in the groups with deterioration of stability or centrality of fixation. The prevalence of cystoid macular changes was significantly higher in the groups with eccentric or unstable fixation (P < 0.001). Generalized linear model statistical analysis showed that logMAR BCVA was significantly associated with stability of fixation (P = 0.020), mean central 8 degrees retinal sensitivity (P < 0.001), and mean OCT foveal thickness (P < 0.001). The interaction between stability of fixation and mean OCT foveal thickness showed a statistically significant association with logMAR BCVA (P = 0.003). Some eyes with eccentric fixation presented with stable fixation, especially in the presence of long-lasting symptoms, and had better visual acuity than eyes with central, but unstable fixation.

CONCLUSION

Visual acuity, central retinal sensitivity, foveal thickness, duration of symptoms, HbA1c levels, and presence of cystoid macular changes were strongly associated with fixation impairment in type 2 diabetic patients who had clinically significant macular edema with a diffuse pattern. Stability of fixation and foveal thickness play a major role in conditioning BCVA.

Immunohistochemical findings in epiretinal membrane after long-term silicone oil tamponade: case report

PURPOSE

To report pre- and post-operative macular optical coherence tomography (OCT) and immunohistochemical findings in a case of long-lasting silicone oil tamponade followed by silicone oil removal and epimacular membrane peeling.

METHODS

A 69-year-old man with long-standing silicone oil tamponade and an epiretinal membrane at the posterior pole in his right eye (RE) underwent silicone oil/BSS exchange with epiretinal membrane peeling. Preoperatively, RE best-corrected visual acuity was 20/200 and macular OCT examination revealed a small increase in foveal thickness (250 microm) with the appearance of a linear hyper-reflective signal at the foveal vitreoretinal interface and a thicker (440 microm) hyperreflective finding causing posterior shadowing at the vitreoretinal interface inferiorly to the fovea. Histopathologic and immunohistochemical study of the specimen including the epiretinal membrane was performed.

RESULTS

Light microscopy revealed extensive rounded empty spaces interpreted as silicone oil bubbles in the preretinal membrane. Macrophages marker (CD68) positive staining cells were found surrounding the empty spaces within the preretinal membrane and several empty spaces were observed intracellularly within macrophage cytoplasm. Thirty days after surgery best-corrected visual acuity was 20/60 and OCT examination showed an evident decrease in foveal thickness (220 microm) with the disappearance of any hyper-reflective signal at the vitreoretinal interface referable to an epiretinal membrane.

CONCLUSIONS

The immunohistochemical study showed both silicone oil droplets and macrophagic cells embedded in the epiretinal membrane. Postoperative OCT demonstrated retinal recovery after silicone oil removal and epiretinal membrane peeling, thus justifying an unexpected visual acuity recovery despite the very long term tamponade.

Epithelial dendritic cell distribution in normal and inflamed human cornea: in vivo confocal microscopy study

PURPOSE

To evaluate dendritic cell (DCs) density, distribution, and morphology in central corneal and limbal epithelium in normal subjects and patients with immune-mediated corneal inflammation using in vivo confocal microscopy (IVCM).

DESIGN

Comparative case-controlled, observational confocal microscopy study.

METHODS

A total of 135 eyes of 135 patients were investigated. Group 1 (normal eyes) included 45 eyes of 45 healthy volunteers, group 2 photorefractive keratectomy (PRK-treated eyes) included 45 myopic eyes of 45 patients treated with PRK, and group 3 (inflamed eyes) comprised 45 eyes of 45 patients affected by immune-mediated corneal inflammation. The central cornea and limbus were examined for epithelial dendritic-shaped cells using laser scanning IVCM. DCs density was calculated using image analysis software.

RESULTS

Cells with a branching dendritic morphology were visualized in the basal epithelial layer, basal lamina, and subbasal nerve plexus, in the central cornea, and in the basal layer and basal membrane of the limbal epithelium. The limbal epithelium demonstrated DCs in 93.3%, 89%, and 97.7% of eyes in group 1, 2, and 3, respectively (P = ns). Central epithelial DCs were observed in 20.0% and 13.3% of eyes in group 1 and 2 (P = ns), while in 93.3% of eyes in group 3 (P < .001). DCs were found to be significantly higher at the limbus compared with central cornea in each group (P < .001). Cell densities observed in group 3 were significantly greater than groups 1 and 2, at both locations (P < .05).

CONCLUSIONS

Laser scanning IVCM is a useful method for evaluating epithelial DCs distribution at the limbus and central cornea in both healthy and diseased eyes.

Humphrey Matrix Frequency Doubling Technology Perimetry and Optical Coherence Tomography Measurement of the Retinal Nerve Fiber Layer Thickness in Both Normal and Ocular Hypertensive Subjects

PURPOSE

The purpose of this study was to determine by means of the Humphrey Matrix frequency doubling technology (FDT) perimetry and the optical coherence tomography (OCT) retinal nerve fiber layer (RNFL) thickness measurement whether functional and/or structural differences exist between normal and ocular hypertensive (OHT) subjects.

PATIENTS AND METHODS

One eye of 60 consecutive normal individuals and 60 OHT subjects was enrolled in this prospective observational comparative case series study. All subjects were examined at either the Ophthalmology Clinic, University of Chieti-Pescara, Chieti, Italy or the Department of Ophthalmology, S. Maria della Misericordia Hospital, Udine, Italy. All subjects underwent a full ophthalmic examination, including visual acuity, slit-lamp biomicroscopy, central corneal thickness ultrasound pachymetry measurement, achromatic automated perimetry, Matrix FDT perimetry, stereoscopic optic nerve head photography, and OCT. Matrix FDT perimetry mean deviation (MD), pattern standard deviation, glaucoma hemifield test, and 12 OCT RNFL thickness parameters were examined. Student t test, Bonferroni correction for multiple comparisons and receiver operator characteristics curve areas (AUROCs) were used to find any discrimination function between healthy and OHT eyes. Sensitivities at 83% and 92% specificities were reported.

RESULTS

The FDT MD scores ranged from -1.10 to +3.80 decibels (db) in normal individuals and from -4.75 to +3.20 db in OHT subjects. The comparison between the average MD in the 2 groups showed a statistically significant difference (P=0.024). OCT showed a statistically significant difference between the 2 groups when examining the ratio between the inferior and the superior mean RNFL thickness (P=0.004). For OCT, the parameter with the largest AUROC for discriminating between healthy and hypertensive eyes was the ratio between the mean inferior and superior RNFL thickness (AUROC=0.85, sensitivity=75% at specificity=83%, sensitivity=67% at specificity=92%). For Matrix FDT perimetry, the parameter with the largest AUROC was MD (AUROC=0.78, sensitivity=67% at specificity=83%, sensitivity=58% at specificity=92%).

CONCLUSIONS

Our results suggest that OHT eyes having a normal achromatic automated perimetry and a normal clinical disc appearance cannot be differentiated from normal eyes using conventional OCT parameters. When analyzing the ratio between inferior and superior average RNFL thickness, however, a significant difference is evident between healthy and hypertensive eyes. Using Matrix FDT perimetry, a significant difference in MD seems to exist between these 2 groups of eyes. The AUROCs confirm that OCT Iavg/Savg and Matrix FDT MD show the greatest sensitivity and specificity among the examined OCT and Matrix FDT parameters.

Zyoptix wavefront-guided versus standard photorefractive keratectomy (PRK) in low and moderate myopia: randomized controlled 6-month study

PURPOSE

To evaluate the refractive and aberrometric outcome of wavefront-guided photorefractive keratectomy (PRK) compared to standard PRK in myopic patients.

METHODS

Fifty-six eyes of 56 patients were included in the study and were randomly divided into two groups. The study group consisted of 28 eyes with a mean spherical equivalent (SE) of -2.25+/-0.76 diopters (D) (range: -1.5 to -3.5 D) treated with wavefront-guided PRK using the Zywave ablation profile and the Bausch & Lomb Technolas 217z excimer laser (Zyoptix system) and the control group included 28 eyes with a SE of -2.35+/-1.01 D (range: -1.5 to -3.5 D) treated with standard PRK (PlanoScan ablation) using the same laser. A Zywave aberrometer was used to analyze and calculate the root-mean-square (RMS) of total high order aberrations (HOA) and Zernike coefficients of third and fourth order before and after (over a 6-month follow-up period) surgery in both groups. Preoperative and postoperative SE, un-corrected visual acuity (UCVA), and best-corrected visual acuity (BCVA) were evaluated in all cases.

RESULTS

There was a high correlation between achieved and intended correction. The differences between the two treatment groups were not statistically significant for UCVA, BCVA, or SE cycloplegic refraction . Postoperatively the RMS value of high order aberrations was raised in both groups. At 6-month control, on average it increased by a factor of 1.17 in the Zyoptix PRK group and 1.54 in the PlanoScan PRK group (p=0.22). In the Zyoptix group there was a decrease of coma aberration, while in the PlanoScan group this third order aberration increased. The difference between postoperative and preoperative values between the two groups was statistically significant for coma aberration (p=0.013). No statistically significant difference was observed for spherical-like aberration between the two groups. In the study group eyes with a low amount of preoperative aberrations (HOA RMS lower than the median value; <0.28 microm) showed an increase of HOA RMS while eyes with RMS higher than 0.28 microm showed a decrease (p<0.05).

CONCLUSIONS

Zyoptix wavefront-guided PRK is as safe and efficacious for the correction of myopia and myopic astigmatism as PlanoScan PRK. Moreover this technique induces a smaller increase of third order coma aberration compared to standard PRK. The use of Zyoptix wavefront-guided PRK is particularly indicated in eyes with higher preoperative RMS values.