Reduction of Foveal Avascular Zone After Vitrectomy Demonstrated by Optical Coherence Tomography Angiography.

PURPOSE: To investigate the effect of pars plana vitrectomy on foveal circulation, and in particular the foveal avascular zone (FAZ), using optical coherence tomography angiography (OCTA). METHODS: This was a prospective, non-randomized, comparative case series of patients that underwent vitrectomy. Twenty-six eyes of 26 patients that underwent vitrectomy were studied postoperatively by OCTA. Our patients underwent 23 or 25G pars plana vitrectomy (PPV) for any posterior segment pathology. Three-dimensional OCTAs (DRI Triton Swept Source OCT; Topcon) of the capillary plexus were obtained three months post-operatively. The FAZ measurements of the fellow eyes were used as controls. MAIN OUTCOME MEASURES: Change in FAZ area between vitrectomized eyes and controls. RESULTS: From a total of 26 patients, 17 underwent vitrectomy due to retinal detachment (RD). Almost all patients demonstrated a statistically significant reduction in FAZ size based on the OCTA measurements. Τhe mean difference in FAZ size for the superficial capillary plexus (SCP) was -93.77 ± 71.73 µm and for the deep capillary plexus (DCP) -88.87 ± 75.41 µm, both statistically significant (p=0.000), while the amount of reduction in µm was the same for both SCP and DCP. CONCLUSION: The foveal avascular zone seems to be reduced following vitrectomy as shown by optical coherence tomography angiography. It is postulated that this may be the result of changes in the physiology of the vitrectomized eye, and that this change should be attributed to the removal of the vitreous itself rather than other structures such as the internal limiting membrane.

Equine pericardium for tectonic globe repair.

PURPOSE: To describe the use of equine pericardium as an off-label temporary emergency treatment of scleral and corneal perforations. METHODS: Three eyes of two male patients aged 34 and 38 years were included, i.e. a case with a history of severe bilateral thermal burn undergoing phacoemulsification complicated by tearing of the main port causing iris exposure and a patient with bilateral corneal perforation secondary to non-infectious corneal melt due to presumed ocular non-steroid anti-inflammatory drug abuse. The equine pericardium patch was soaked in balanced salt solution, trimmed and sutured over the perforated area with interrupted nylon 10-0 sutures. Slit-lamp photographs were taken before and immediately after surgery as well as at 2 and 5 months postoperatively. RESULTS: A watertight closure of the perforation was achieved in both cases. No evidence of infection, severe inflammation, leakage or hypotony was detected throughout the observation period. The first patient developed a pseudopterygium over the pericardium patch 5 months after surgery. The second patient showed at 2 months a bilateral melt of the pericardium and loosening of the sutures. After removal of the latter, a tectonically stable scar was evident in both eyes. CONCLUSION: Equine pericardium offered an effective primary treatment in cases of non-infectious globe perforation and may be considered when other materials, e.g. amniotic membrane, corneal or scleral allografts, are not readily available. Further studies may further elucidate the safety and efficacy profile of this biomaterial in ophthalmic surgery.

Acute ocular pain during magnetic resonance imaging due to retained intraocular metallic foreign body: the role of ultrasonography and ultrasound biomicroscopy in diagnosis and management of this condition.

PURPOSE: To report the case of a 65-year-old metalworker with no known history of ocular trauma, who suffered from intense ocular pain during magnetic resonance imaging (MRI) of the brain, due to a retained intraocular metallic foreign body (IOFB). CASE REPORT: Meticulous ophthalmological examination was inconclusive. An IOFB was confirmed with X-ray scan, whereas its exact localization was enabled by means of ultrasonography and ultrasound biomicroscopy (UBM). CONCLUSIONS: Despite appropriate screening protocols, MRI-related ocular complications might occur in the presence of a hidden metallic IOFB. Clinical detection of ocular foreign bodies can sometimes be challenging. Ultrasonography and UBM are valuable adjuncts for the accurate localization, especially of small or hidden particles.

Supradescemetic voriconazole injection for Candida parapsilosis keratitis.

PURPOSE: To describe a technique for intracorneal application of voriconazole into the supradescemetic space in a case of deep recalcitrant Candida parapsilosis keratitis of a penetrating cornea graft. METHODS: A deep intracorneal incision reaching the center of the corneal infiltrate was created with a 20-gauge MVR blade. Then, a 27-gauge hydrodissection cannula was inserted deep into the corneal pocket, and 0.1 ml of voriconazole 0.5 mg/ml was injected until a bullous detachment of Descemet membrane (DM) covered 1/3 of the graft's area. DM detachment was documented by anterior segment optical coherence tomography (AS-OCT). RESULTS: AS-OCT confirmed the creation of a drug depot in the supradescemetic space, which partially regressed during the following hours; 24 h after the injection, a complete reattachment of DM was documented. After 4 weeks, the stromal infiltrate has cleared completely and no signs of recurrence were observed 3 months after injection. CONCLUSION: In the present case, the supradescemetic voriconazole injection led to resolution of a deep recalcitrant fungal infiltrate. The herein described technique could be tried in similar cases, where an intrastromal injection is indicated, as it may offer a larger intracorneal drug depot.

Goldmann Applanation Tonometry versus Dynamic Contour Tonometry after Vitrectomy with Silicone Oil Endotamponade.

PURPOSE: To evaluate the agreement of intraocular pressure (IOP) measurements using dynamic contour tonometry (DCT) and Goldmann applanation tonometry (GAT) in eyes after vitrectomy with silicone oil endotamponade and controls. METHODS: In this prospective comparative study, IOP was measured with GAT and DCT in 30 eyes with oil endotamponade 1-3 days after vitrectomy and 40 untreated controls. In addition, ocular pulse amplitude (OPA), corneal pachymetry (CCT), and axial length (AL) were measured. RESULTS: GAT values in the oil group were significantly higher compared to control eyes (mean GAT oil 13.6 ± 5.1 mmHg; mean GAT control 10.8 ± 2.1 mmHg; p = 0.003). There was no significant difference in DCT measurements (mean DCT oil 12.0 ± 4.1 mmHg; mean DCT control 11.9 ± 2.9 mmHg; p = 0.9). This led to a significant difference of GAT-DCT between the oil and control group (mean difference of GAT-DCT oil 1.6 ± 4.7 mmHg; mean difference of GAT-DCT control -1.1 ± 2.6 mmHg; p = 0.004). The difference between GAT and DCT was negatively correlated with the mean IOP measured by both methods (r = -0.36, p = 0.02) and positively correlated with CCT only in the control group (r = 0.36, p = 0.02), as well as to AL only in the oil group (r = 0.46, p = 0.01). The OPA did not differ significantly between groups. CONCLUSION: GAT and DCT showed a good agreement in control eyes. The difference of GAT and DCT is significantly changed in eyes after vitrectomy with silicone oil endotamponade. Our findings suggest that GAT overestimates IOP in this situation.

Goldmann Applanation Tonometry Versus Dynamic Contour Tonometry After Vitrectomy.

PURPOSE: The aim of the study was to investigate the agreement of intraocular pressure (IOP) measurement using dynamic contour tonometry (DCT) and Goldmann applanation tonometry (GAT) in eyes after vitrectomy with intraocular gas endotamponade, in eyes after vitrectomy with no tamponade, and in controls. METHODS: In this prospective comparative study IOP was measured with GAT and DCT in 41 eyes with gas endotamponade (sulfur hexafluoride 20%) 1 to 3 days after vitrectomy, in 32 postvitrectomy eyes with intraocular water, and in 46 control eyes with no history of glaucoma or intraocular surgery. Corneal pachymetry and axial length measurements were additionally performed. RESULTS: The mean difference between GAT and DCT (GAT-DCT) in gas-filled eyes was 3.1 mm Hg [SD=6.2 mm Hg], that in eyes after vitrectomy with no tamponade was 0.4 mm Hg (SD=4.8 mm Hg), and in control eyes was 0.4 mm Hg (SD=3.8 mm Hg). No significant correlation was found between the differences of GAT and DCT (GAT-DCT) and the mean IOP of GAT and DCT in water-filled eyes (r=-0.25, P=0.18) and control eyes (r=0.23, P=0.13), but a significant correlation was found in the gas-filled eyes (r=0.71, P<0.0001). A significant correlation between central corneal thickness and the mean difference of both methods was seen only in the control group (r=0.36, P=0.03). CONCLUSIONS: IOP as determined by DCT underestimates IOP in gas-filled eyes compared with GAT, as GAT values were on average 3.1 mm Hg higher compared with those of DCT. The extent of IOP underestimation using DCT increases with higher IOP values. In the group of eyes after vitrectomy and in normal eyes we found a generally good agreement between the 2 methods, although high interindividual discrepancies were present. Our findings suggest that the 2 devices should not be used interchangeably in IOP evaluation after vitrectomy with gas endotamponade, which remains a difficult challenge.

Tonometry in corneal edema after cataract surgery: rebound versus goldmann applanation tonometry.

PURPOSE: Goldmann applanation tonometry (GAT) is known to be influenced by corneal properties, whereas the effect of corneal edema on intraocular pressure (IOP) measurement using Rebound tonometry (RT) is not clear. In this study, IOP was measured before and after cataract surgery using GAT and RT to investigate differences between methods and the effect of postsurgical corneal edema. METHODS: Thirty patients with cataract were included in a prospective study. IOP was measured using GAT and RT (Icare PRO, Tiolat Oy, Finland) before and after one day of phacoemulsification. Central corneal thickness (CCT) was determined before and after surgery (Pentacam, Oculus, Germany). RESULTS: CCT increased significantly after surgery by 52.2 ± 35.1 µm (p < 0.0001). IOP values of GAT and RT were significantly correlated before surgery (r = 0.65, p < 0.0001) and after surgery (r = 0.94, p < 0.0001). No significant correlation of GAT and RT to CCT before surgery (GAT: r = 0.18, p = 0.36; RT: r = 0.03, p = 0.87) or after surgery (GAT: r = -0.08, p = 0.69; RT: r = 0.17, p = 0.37) was found. The mean difference between GAT and RT (GAT-RT) was -1.0 ± 2.9 mmHg (range -6.2 to 6.4 mmHg, p = 0.08) before surgery and -1.1 ± 2.2 mmHg (range -5.1 to 4.8 mmHg, p = 0.01) after surgery. Before surgery, a positive correlation of GAT-RT with mean IOP of both methods is apparent (r = 0.45, p = 0.01). After surgery, no such correlation was found (r = -0.08, p = 0.69). CONCLUSIONS: RT underestimates IOP in higher values and overestimates IOP in lower values compared to GAT before surgery. This is not apparent in eyes with corneal edema. Large differences between methods may be present in individual patients with and without corneal edema.