Intraocular pressure measurement after DSAEK by iCare, Goldmann applanation and dynamic contour tonometry: A comparative study

Challenges in the complex management of post-keratoplasty glaucoma

Glaucoma is a serious complication after corneal transplantation and itself a common cause for graft failure and leading cause of vision loss post-keratoplasty due to corneal endothelial decompensation. Endothelial keratoplasty procedures like Descemet stripping automated endothelial keratoplasty (DSAEK) and Descemet membrane endothelial keratoplasty (DMEK) may be superior to penetrating keratoplasty (PK) regarding the incidence of elevated intraocular pressure (IOP) and development of glaucoma. There are indications that regardless of the method of keratoplasty, some corneal diseases like pseudophakic bullous keratopathy, corneal perforation, and graft rejection have a higher risk for developing post-keratoplasty glaucoma than keratoconus and corneal dystrophies and likewise respond less to IOP lowering therapy. In this review, the pathophysiology of post-keratoplasty glaucoma, the diagnostic tools with focus on different devices, and their limitations with regard to measuring IOP and the treatment modalities are presented.

Demographic and clinical profile, surgical outcome, and quality of life in patients who underwent bilateral lamellar corneal grafts

Purpose:

Lamellar corneal grafts have revolutionized the management of corneal blindness by replacing only the disease specific corneal layers. To the best of our knowledge, there is no study in literature describing the outcomes of bilateral lamellar keratoplasty in the Indian population. The aim of this work was to study the demographic profile, surgical outcomes, and quality of life in patients who underwent bilateral lamellar keratoplasty and to assess the correlation between these three.

Methods:

An observational cross-sectional study was conducted on 47 patients who underwent bilateral deep anterior lamellar keratoplasty (DALK) (n = 31) or descemet stripping automated endothelial keratoplasty (DSAEK) (n = 16) with a minimum follow-up of 6 months after the second surgery. Demographic parameters were collected by interview, surgical outcomes by clinical examination, and quality of life by a questionnaire.

Results:

A total of 47 patients were evaluated, women 42.56%, (n = 20) and men 57.44% (n = 27) with 38.3% being in 18–30 years age group and 23.4% above 60 years; 17.02% patients had a good socioeconomic status (score >60) and 61.70% had poorer socioeconomic status (score <50). Quality of life score (VR-QoL) was ≥50 in 82.9% patients and ≥70 in 14.89%. No significant association existed between VR-QoL scores and demographic factors. However, statistically significant association existed between VR-QoL and age of patient (P < 0.05), postoperative vision (P ≤ 0.05), and contrast sensitivity (P ≤ 0.01).

Conclusion:

Bilateral lamellar corneal grafts provide satisfactory visual outcomes compatible with day-to-day functioning. VR-QoL has a direct correlation to the age, visual acuity, contrast sensitivity, and inverse correlation with lenticule thickness in DSAEK and residual bed thickness in DALK.

Incidence and Risk Factors of Ocular Hypertension/Glaucoma After Descemet Stripping Automated Endothelial Keratoplasty

Purpose

To evaluate the incidence, demographics, associated risk factors, management and clinical outcomes of ocular hypertension/glaucoma after Descemet stripping automated endothelial keratoplasty (DSAEK).

Methods

A cohort review of 81 DSAEK cases was performed at Queen Victoria Hospital, United Kingdom. Patients with pre-existing glaucoma, transient increased IOP within the first 48 hours post-graft, additional post-transplant surgery, or failed to complete one year follow-up were excluded from the study. Ocular hypertension was defined as intraocular pressure (IOP) elevation >21mmHg or ≥6mmHg from baseline at any postoperative visit. The study looked at the incidence, risk factors, response to anti-glaucoma treatment, graft failure and best corrected visual acuity.

Results

The incidence of post-DSAEK ocular hypertension and glaucoma was 51.9% and 13.6%, respectively. Steroid-induced IOP elevation was the most frequent cause, with an incidence of 38.3%. Risk factors such as pseudophakia (p=0.024) and preoperative IOP>16 (p=0.003) were found to be associated with post-DSAEK ocular hypertension. Preoperative IOP>16 had 5.27 times risk of IOP elevation. Eyes with graft dislocation and/or detachment were significantly associated with post-DSAEK glaucoma (p=0.038). There was no negative effect of OHT on visual acuity and graft status.

Conclusion

Glaucoma and OHT are common postoperative complications of DSAEK. Although steroid-induced IOP elevation was the most frequent cause, there are other reasons associated with development of post-DSAEK glaucoma, including graft dislocation and detachment. Eyes with preoperative IOP>16 mm Hg may require a close monitoring of IOP. In addition, management by medical treatment results in good visual acuity and graft clarity.

Comparison of the iCare, Tono-Pen, non-contact airpuff, and Goldmann applanation tonometers in eyes with corneal edema after penetrating keratoplasty

BACKGROUND

To compare the utility of the iCare, Tono-Pen, and non-contact airpuff (NCT) tonometers with the Goldmann applanation tonometer (GAT) for measuring intraocular pressure (IOP) in patients with corneal edema after penetrating keratoplasty (PKP) and to assess the effects of central corneal thickness (CCT) and corneal curvature (CC) on IOP measurements.

METHODS

Thirty-two eyes of 27 patients with corneal edema after PKP due to corneal abnormalities and 43 control eyes of 30 patients with normal corneas were recruited. Before IOP measurements, all patients underwent a baseline examination, including auto-refraction, keratometry, slit lamp biomicroscopy, and CCT measurement. IOP was measured using the devices in the same order: first the NCT, followed by the iCare, Tono-Pen, and GAT. The differences between the iCare, Tono-Pen, NCT, and GAT were calculated with repeated-measures analysis of variance. The Bland-Altman method was used to assess the agreement between the iCare, Tono-Pen, and NCT versus the GAT. The influences of CCT and CC on IOP measurement were evaluated by correlation analysis using Pearson's correlation coefficient.

RESULTS

Mean IOP measurements were significantly higher with the NCT and Tono-Pen than with the GAT in the PKP and control groups. When compared with GAT, iCare showed significantly higher IOP readings in the control group, but the IOP readings did not differ between the iCare and GAT in the PKP group. Poor agreement was noted between the NCT and GAT in both groups. The Tono-Pen showed clinically acceptable agreement with GAT in control eyes and poor agreement in PKP eyes. The agreement between the iCare and GAT appeared to be clinically acceptable in both groups. Correlation analysis of the results from control eyes showed that the IOP measurements with the GAT and NCT were weakly related to CCT and moderately correlated with CC. The iCare IOP readings were weakly correlated with CCT and CC.

CONCLUSION

In the PKP group, the NCT and Tono-Pen significantly overestimated IOP, whereas the iCare IOP readings were similar to those obtained using the GAT. Poor agreement was noted between the NCT and GAT as well as between the Tono-Pen and GAT, but the iCare showed clinically acceptable agreement with GAT. In normal corneas, the GAT, NCT, and iCare were affected by CCT and CC. The iCare tonometer was less affected by corneal edema than were the NCT and the Tono-Pen. The iCare appears to be a useful device for IOP measurement in eyes with corneal edema after PKP.

Risk Factors for the Development of Ocular Hypertension After Keratoplasty: A Systematic Review

Supplemental Digital Content is Available in the Text.

To identify risk factors for the development of ocular hypertension after keratoplasty.

Clinical Features of Graves' Ophthalmopathy and Impact of Enalapril on the Course of Mild Graves' Ophthalmopathy: A Pilot Study

BACKGROUND

Inflammation, oxidative stress, and adipogenesis are associated with Graves' ophthalmopathy (GO) progression.

OBJECTIVE

We conducted a pilot study to investigate the effect of Enalapril on patients with mild ophthalmopathy.

METHOD

Based on the comprehensive eye examination, 12 patients with mild ophthalmopathy were selected from referred Graves' patients and treated with Enalapril (5 mg daily) for 6 months. Clinical and ophthalmological examination [IOP (Intraocular Pressure), vision, Margin reflex distance and exophthalmia measurement, CAS (clinical activity score) and VISA [V (vision); I (inflammation/ congestion); S (strabismus/motility restriction); and A (appearance/exposure] score assessment) was performed at the beginning, 3 months and 6 months of the study period. Quality of life was also evaluated using a standard questionnaire.

RESULTS

Mean exophthalmia at the first visit was 18.75 ± 2.39, 3 months later 18.53 ± 2.39 and 6 months later was 17.92 ± 2.31, respectively. Mean CAS was 0.71 ± 0.82 (first visit), 0.57 ± 0.54 (3 months) and 0.14 ± 0.36 (6 months), respectively. Mean Margin reflex distance was 9.09 ± 4.36 (first visit) and 9.60 ± 4.40 (6 months), respectively. There were significant differences in the case of exophthalmia (P=0.002), CAS (P=0.006), and Margin reflex distance (P=0.029) between the first visit and 6 months after treatment. The difference between the score of quality of life in patients with GO after 6 months of follow up was statistically significant (P = 0.006).

CONCLUSION

Our results showed that Enalapril treatment could ameliorate the clinical course of GO according to the ophthalmologic examinations and subjective parameters of disease progression. However, further studies should be performed to determine the efficacy of Enalapril in Graves' ophthalmopathy treatment.

The Effect of Corneal Thickness, Densitometry and Curvature on Intraocular Pressure Measurements Obtained by Applanation, Rebound and Dynamic Contour Tonometry

Evaluate the effect of corneal thickness, densitometry and curvature on intraocular pressure (IOP) measurements obtained by Goldmann applanation tonometry (GAT), non-contact tonometry (NCT), rebound tonometry (RT), and dynamic contour tonometry (DCT). A cross-sectional prospective study involving 40 participants was performed. Corneal measurements were obtained using Pentacam (Oculus GMbH, Wetzlar, Germany), densitometry was measured at annuli of 0–2, 2–6, 6–10 and 10–12 mm. The relationship between corneal thickness (central, 4 and 6 mm), corneal astigmatism and corneal densitometry and IOP was examined. There was a significant relationship between corneal thickness (central, 4 and 6 mm) and GAT180, GAT90, RT, and NCT (P < 0.001 for all comparisons) but not for DCT. Higher corneal densitometry (6–10 mm and 10–12 mm zones) was associated with higher IOP from GAT180 and GAT90, and higher densitometry in the 6–10 mm zone correlated with higher IOP from NCT, however corneal densitometry increased with age. Accounting for age, the relationship between corneal densitometry and IOP measurements was not significant. In eyes with greater corneal astigmatism there was a greater difference between GAT90 and GAT180 measurements. IOP measurements may be affected by corneal thickness, densitometry and curvature. DCT was less affected by properties of the cornea compared to other devices.

[Experimental simulation for determining optimal design parameters of a transpalpebral tonometry sensor]

PURPOSE

To determine optimal design parameters of a transpalpebral tonometry sensor (the weight and diameter of the rod) based on experimental simulation.

MATERIAL AND METHODS

The study has been conducted in situ at the forensic analysis department with 12 eyes of 5 men and one woman aged 49 to 71 years. Comparison between the tonometric pressure and the true pressure measured with direct manometric technique ensured the accuracy of transpalpebral tonometry data and helped select optimal sensor parameters. For this purpose, an experimental assembly was designed and produced, comprised of a testing stand with a system of tubes filled with distilled water, an indicating pressure gauge calibrated by the height of the water column, a millimeter scale on a holder, as well as a needle with connecting tubes and two valves.

RESULTS

No statistically significant differences between the tonometric and manometric level of pressure in the eye were observed when using a sensor weighing 16 g with rod diameter of 1.5 or 3 mm. Only an insignificant dependence of the tonometry data on the thickness of the eyelid was noted at high levels of intraocular pressure (IOP).

CONCLUSION

The experimental study conducted on the developed assembly has allowed us to substantiate the choice of optimal design parameter for a transpalpebral IOP measurement sensor. A transpalpebral tonometer with such sensor characteristics can be recommended for comparative clinical study, as well as for determination of its effectiveness in dynamical monitoring of the IOP levels.

Prophylactic exposure of human corneal endothelial cells to Rho-associated kinase inhibitor reduced apoptosis rate after phacoemulsification: Ex vivo study

PURPOSE

To evaluate whether prophylactic exposure of corneal endothelial cells (CECs) to a selective Rho-associated kinase (ROCK) inhibitor will inhibit CEC apoptosis after phacoemulsification.

SETTING

Laboratory evaluations at the Edith Wolfson Medical Center, Holon, Israel and the Chaim Sheba Medical Center, Tel-Hashomer, Ramat-Gan, Israel and the Chaim Sheba Medical Center, Tel-Hashomer, Ramat-Gan, Israel.

DESIGN

Experimental study.

METHOD

Human donor corneolimbal rings were divided into fragments that were stored in commercial storage media with or without the addition of 10 mM ROCK inhibitor for 1 week and were then exposed to phacoemulsification energy. Samples were dissociated into single cells by trypsin digestion and CECs were targeted using the antihuman CD166 antibody, a new biomarker. The CEC survival was evaluated for early and late apoptosis rate with flow cytometric analysis of annexin-V and propidium iodide (PI) double staining.

RESULTS

Six corneoscleral rings from 4 donors were studied. After phacoemulsification, CEC exposed to ROCK inhibitor demonstrated a 37.06% reduction in early apoptosis rate (29.36% ± 4.33% [SD] versus 46.65% ± 1.51%, P = .006) and 45.27% reduction in late apoptosis rate (17.6% ± 16.81% versus 32.16% ± 26.30%, P = .007), compared with controls. Subsequently, ROCK levels in apoptotic CECs were significantly lower in cells incubated with ROCK inhibitor than the control medium.

CONCLUSIONS

In this ex vivo study, ROCK inhibitor reduced endothelial loss and thus, could be used to limit or slow down CEC loss. Rho-associated kinase inhibitor might be used before cataract surgery, especially in high risk patients. This might be a promising new method for preventing pseudophakic bullous keratopathy.