Risk Of Corneal Decompensation Research Articles

Overestimation of corneal endothelial cell density by automated method in glaucomatous eyes with impaired corneal endothelial cells

PurposeTo determine between-method differences in corneal endothelial cell parameters using center and automated methods of non-contact specular microscopy (CellCheck software of Konan, Inc.) in glaucomatous eyes.MethodsWe analyzed the central corneal endothelial cell density (ECD) of 245 glaucomatous eyes using center (ECD-Ce) and automated methods (ECD-Au). Based on the ECD-Ce, we allocated subjects to Groups 1 to 10 (at 250 cells/mm2 intervals) and evaluated the ECD, coefficient of variation in cell area (CV), and percentage of hexagonal cells (HEX).ResultsThere was a close correlation (r = 0.91) between the ECD values measured using both methods. However, ECD-Au were significantly higher than those measured by the center method when ECD-Ce was less than 2500 (in Groups 1 to 8; P < 0.001 to P = 0.006). The regression equation of (ECD-Au—ECD-Ce) = 1028–0.397*ECD-Ce shows greater deviation in eyes with lower ECD, and this difference became 0 when ECD -Ce was 2593 cells/mm2. None of the 44 subjects with an ECD-Ce of < 1000 cells/mm2 recorded an ECD-Au < 1000 cells/mm2. Compared with the center method, the automated method had higher and lower median CV and HEX values, respectively (P < 0.001). The between-method differences in both CV and HEX were negatively correlated with ECD-Ce (r = −0.49, P < 0.001 and r = −0.25, P < 0.001, respectively).ConclusionThe automated method of the CellCheck software overestimates ECD in eyes with lower ECD values and may overlook risk of corneal decompensation.

Fuchs endothelial corneal dystrophy and small eyes

Aim: To determine whether there is an association between Fuchs endothelial corneal dystrophy (FECD) and shorter axial length (AL), shallower anterior chamber depth (ACD) and higher spherical equivalent (SE). In addition, to evaluate whether there is a correlation between AL and severity of corneal decompensation in FECD, using corneal thickness as a proxy.&#x0D; Design: Retrospective cohort study.&#x0D; Methods: This was a single-centre study conducted in a cornea clinic in Sydney, Australia. Detailed clinical measurements of 91 eyes of 50 FECD patients were compared with 110 eyes of 55 controls. Main outcome measures included AL, ACD and SE. Other outcome measures included central corneal thickness, visual acuity, intraocular pressure and keratometry.&#x0D; Results: Mean AL of FECD patients was 23.6 mm (standard deviation [SD] ±0.9 mm), compared with 24.7 mm (SD ±1.8 mm) for controls (1.1 mm difference [95% confidence interval [CI] 0.5-1.6], p &lt; 0.001, independent sample t-test); corresponding means for ACD were 3.0 and 3.3 mm (0.32 mm difference [95%CI 0.2-0.5], p &lt; 0.001, independent t-test). Eleven out of the 22 FECD patients with available refraction data had hypermetropic refraction compared with 16 out of 36 controls (p = 0.68, chi-squared test). The mean SE of FECD patients (+0.10D) was higher than controls (−1.33D) (1.4D difference [0.1-2.8], p = 0.04, independent t-test). No statistically significant correlation was found between AL and corneal thickness (p = 0.28, linear regression).&#x0D; Conclusion: In this retrospective cohort study, a strong association was established between FECD and small eyes, with shorter AL and shallower ACD, compared with controls. These results have important implications for surgical planning, as shorter AL and ACD in FECD patients likely contribute to their high risk of corneal decompensation following cataract surgery.

A Meta-analysis on the Outcome of Sequential Glaucoma Drainage Implantation.

A meta-analysis shows that second glaucoma drainage implantation can be effective after a failed drainage implant. There is a need for continued glaucoma medications and the risk of corneal decompensation. Studies on second glaucoma drainage implantation are small and exploratory. We performed a meta-analysis on the efficacy of second glaucoma drainage implantation. The intraocular pressure (IOP) and the number of glaucoma medications were compared preoperative to postoperative after second drainage implantation. Kaplan-Meier survival curves were aggregated and compared with the survival curve from the Tube versus Trabeculectomy study. Nine studies, all retrospective, were included in the meta-analysis. Our results showed that second drainage implantation significantly lowered the IOP and reduced the number of medications. Most patients still required medications for adequate IOP control. Second drainage implants tended to fail earlier than first drainage implants in the Tube versus Trabeculectomy study. The most common complication after second drainage implants was corneal decompensation. Second glaucoma drainage implantation can be considered a viable approach after a failed drainage implant, but patients should be counseled on the need for continued medical therapy and the risk of corneal decompensation.

A Case Report Discussing The Options for Placement of Glaucoma Drainage Devices in the Presence of Corneal Decompensation

Purpose: The purpose of this case report is to discuss how the various placements of glaucoma drainage implants relate to corneal decompensation. Method: A 58-year Hispanic female presented for evaluation of decreased vision in the left eye for 2 years. This is a case report of a patient who underwent a secondary surgery to replace the anterior tube shunt implantation with a posterior shunt implantation following development of severe corneal decompensation. Results: Glaucoma tube shunt implants inserted into the ciliary sulcus of pseudophakic eyes shield the cornea offering protection against decompensation and avoid the risk of posterior segment complications. Conclusions: Placement of glaucoma drainage implants into the ciliary sulcus in pseudophakic patients with shallow anterior chambers, abnormal irido-corneal anatomy, or those at risk for corneal decompensation is a safe and effective method of not only lowering the intraocular pressure but also protecting the cornea against decompensation. As primary eye care providers, optometrists need to know the various treatment options and adverse effects associated with each procedure.

Distrofia polimorfa posterior y LASIK

A 50-year-old hyperopic woman requested information about refractive surgery. Vesicle and band lesions at Descemet's membrane and endothelium were suggestive of posterior polymorphous dystrophy (PPD). Lower than normal endothelial cell densities were detected. A corneal refractive procedure was not recommended in this case. The presence of vesicles and bands at Descemet's membrane and endothelium is suggestive of PPD. Specular microscopy is mandatory in such patients, although corneal decompensation is not evident. A low endothelial cell count may be a contraindication for a hyperopic LASIK procedure in cases of PPD because of the possible risk of corneal decompensation.

The human corneal endothelium: New insights into electrophysiology and ion channels

The corneal endothelium is a monolayer that mediates the flux of solutes and water across the posterior corneal surface. Thereby, it plays an essential role to maintain the transparency of the cornea. Unlike the epithelium, the human endothelium is an amitotic cell layer with a critical cell density and the risk of corneal decompensation. The number of endothelial cells subsequently decreases with age. Moreover, the endothelial cell loss is accelerated after various impairments such as surgical trauma (e.g. cataract extraction) and following corneal transplantation. This cell loss is associated with programmed cell death (apoptosis) and changed ion channel activity. However, little is known about the electrophysiology and ion channel expression (in particular Ca2+ channels) in corneal endothelial cells. This article reviews our current knowledge about the electrophysiology of the corneal endothelium. It highlights ion channel expression, which may have a major role in corneal cell physiology and pathological events. A better understanding of the (electro)physiological function of the cornea may lead to the development of clinical relevant new therapeutic and preventive measures.

Corneal Endothelial Cell Density After Complicated Cataract Surgery and Implantation of an Anterior Chamber Intraocular Lens

Objective: To compare corneal endothelial cell densities in eyes with a semiflexible open-loop anterior chamber intraocular lens (AC-IOL) with those in unoperated fellow eyes or in fellow eyes having a posterior chamber intraocular lens (PC-IOL). Study Design and Setting: During the period January 1988 to August 1990 48 AC-IOLs were implanted in eyes in which either an intracapsular cataract extraction was performed or during an extracapsular extraction posterior capsular support was lost. The corneal endothelial cells of 25 of the 48 patients were photographed using a specular microscope 7 to 37 months (median 22) postoperatively. Patients: The mean age of the patients was 72.6 years (range 39 to 86). In 16 cases (group A) the fellow eye was phakic, in nine cases (group B) the fellow eye had a PC-IOL implanted after uncomplicated surgery. Results: In group A the mean cell densities in the operated and unoperated eye were 1726 and 2321/mm 2 , respectively ( P < 0.001), in group B the mean cell densities in eyes with an AC-IOL and a PC-IOL were 1485 and 1900/mm 2 , respectively ( P < 0.05). The presence of glaucoma, exfoliation syndrome or anterior vitrectomy did not reduce the mean cell density. Conclusions: Although the corneal endothelial cell densities were lower in eyes with an AC-IOL than in unoperated fellow eyes or in fellow eyes with uncomplicated cataract surgery and a PC-IOL, the risk of corneal decompensation seems to be small, and therefore the use of an open-loop semiflexible AC-IOL in complicated age-related cataract extraction is justified.