Scheimpflug Corneal Densitometry Changes After Trabeculectomy

Preserflo-MicroShunt: Postoperative Effects on Endothelial Cell Density and Corneal Thickness

Background: The aim of this study was to evaluate the effects of Preserflo implantation on endothelial cell density (ECD), corneal thickness, intraocular pressure (IOP), and the use of antiglaucoma medications over a 12-month follow-up period. Methods: A total of 53 eyes from 53 patients undergoing Preserflo implantation were included in this prospective study. ECD, corneal thickness, IOP, and the number of antiglaucoma medications were measured at baseline, 3 months, and 12 months postoperatively. Statistical analysis was performed using paired t-tests and Wilcoxon signed-rank tests for non-normally distributed data. Results: There was no significant reduction in ECD at 3 months (p = 0.695) or 12 months (p = 0.229) compared to baseline. However, a significant reduction in corneal thickness was observed at 3 months (p = 0.008), with no significant change at 12 months (p = 0.118). A significant reduction in IOP was noted at both 3 months (from a preoperative median of 23.5 mmHg to 11.5 mmHg, p < 0.001) and 12 months (from 23.5 mmHg to 13.0 mmHg, p < 0.001). Additionally, there was a significant decrease in the use of antiglaucoma medications, from a preoperative median of 3.0 medication classes to 0.0 classes at both 3 months (p < 0.001) and 12 months (p < 0.001). Conclusions: Preserflo implantation resulted in a significant reduction in IOP and the need for antiglaucoma medications, with no significant impact on endothelial cell density and corneal thickness after 12 months. These findings suggest that Preserflo implantation is an effective procedure for IOP control and medication reduction, with favorable outcome for corneal health after one year.

Corneal stromal changes following simple limbal epithelial transplantation on Scheimpflug densitometry: Early results

CONTEXT

Chemical injury to eyes causes limbal stem cell deficiency (LSCD), which leads to conjunctival epithelium and underlying stromal changes. Simple limbal epithelial transplant helps to restore corneal epithelium and corneal stromal clarity. These changes are documented in this prospective eye study.

PURPOSE

To report the changes in epithelial/stromal (E/S) reflectivity ratio and corneal stromal densitometry following simple limbal epithelial transplantation (SLET) in patients with unilateral chemical burn-induced LSCD.

METHODS AND MATERIAL

It is a prospective imaging study of cornea before and after SLET. Corneal densitometry with Pentacam and epithelial and stromal reflectivity on anterior segment optical coherence tomography were analyzed for five patients (n = 5 eyes), who underwent autologous SLET for unilateral chemical burn-induced LSCD.

STATISTICAL ANALYSIS USED

Mann-Whitney U-test and Pearson correlation.

RESULTS

A significant improvement in E/S reflectivity was noted at 1 month ( P < 0.05) after SLET, and this was maintained until the end of 6 months. The densitometry measurements decreased in the entire cornea at every level, that is, anterior, central, and posterior cornea. However, the values did not normalize till the last follow-up at 6 months.

CONCLUSIONS

A trend of normal corneal epithelization exists in eyes undergoing SLET. Densitometry at all the levels, the anterior, central, and posterior cornea, also decreases after SLET. SLET improves visual outcomes in LSCD eyes not only by epithelization but also by reducing stromal scarring.

Corneal Clarity and Tomographic Patterns in Pseudoexfoliation Syndrome: A Severity-Based Investigation

PURPOSE

The aim of the study was to investigate the corneal and anterior segment characteristics in pseudoexfoliation syndrome (PXS), depending on the severity of the disease.

MATERIALS AND METHODS

This cross-sectional study was conducted at a tertiary care hospital, in the ophthalmology department, in Turkey. Pseudoexfoliation syndrome group was classified into three groups. Pseudoexfoliative material on the part of the pupillary border was classified as group 1, on the entire pupillary border was classified as group 2, and pseudoexfoliative material on the entire pupillary border and iris surface was classified as group 3. The control group was composed of age and gender-matched individuals who had undergone a completely normal ophthalmologic examination. Scheimpflug tomography was performed to record tomographical data.

RESULTS

The PXS groups 1, 2, and 3, along with the control group, consist of 29, 32, 33, and 42 participants, respectively. There was no significant difference in age-gender distribution between patients and the control group ( P >0.05). Group 3 showed significant differences in central corneal thickness compared with the control group ( P =0.001). In addition, anterior chamber angle was found to be significantly lower in group 3 than the control group ( P <0.001). In corneal densitometry (CD) values, significant increases compared with the control group were observed in groups 2 and 3 across all anterior annuli ( P <0.001). In group 1, significant increases observed in the anterior 6-10 mm and 10-12 mm annuli ( P <0.001). In the middle 6-10 mm annuluses, only group 3 showed a significant increase compared with the control group ( P <0.001). In the posterior 0-2, 2-6, and 6-10 mm annuli, significant increases compared with the control were observed only in groups 2 and 3 ( P =0.001, P =0.001, P <0.001, respectively).

CONCLUSIONS

Corneal densitometry values, even without an increase in intraocular pressure, have a tendency to increase in PXS depending on the severity of the disease. While minimal changes were observed in the middle layer, it was particularly noted that the effects of the disease were more prominent in the peripheral cornea.

Investigation of How Corneal Densitometry Artefacts Affect the Imaging of Normal and Keratoconic Corneas

PURPOSE

To investigate corneal densitometry artefacts found in Pentacam Scheimpflug scans and their potential effect on assessing keratoconic (KC) corneas compared to normal (N) corneas.

METHODS

The current study utilises Pentacam data of 458 N eyes, aged 35.6 ± 15.8 (range 10-87), referred to as the "N group", and 314 KC eyes, aged 31.6 ± 10.8 (range 10-72), referred to as the "KC group", where densitometry data were extracted and analysed via a custom-built MATLAB code. Radial summations of the densitometry were calculated at diameters ranging from 0.5 mm to 5.0 mm. The minimum normalised radial summation of densitometry (NRSD) value and angle were determined at each diameter and then linked. KC cone locations and areas of pathology were determined, and a comparison between N and KC groups was carried out both within the averaged area of pathology and over the corneal surface.

RESULTS

Joining minimum NRSD trajectory points marked a clear distortion line pointing to the nasal-superior direction at 65° from the nasal meridian. The findings were found to be independent of eye laterality or ocular condition. Consistency was detected in the right and left eyes among both the N and KC groups. The location of the KC cone centre and the area of pathology were determined, and the densitometry output was compared both within the area of pathology and over the whole cornea. When the average densitometry was compared between N and KC eyes within the KC area of pathology, the N group recorded a 16.37 ± 3.15 normalised grey-scale unit (NGSU), and the KC group recorded 17.74 ± 3.4 NGSU (p = 0.0001). However, when the whole cornea was considered, the N group recorded 16.71 ± 5.5 NGSU, and the KC group recorded 15.72 ± 3.98 NGSU (p = 0.0467). A weak correlation was found between the Bad D index and NGSU when the whole measured cornea was considered (R = -0.01); however, a better correlation was recorded within the KC area of pathology (R = 0.21).

CONCLUSIONS

Nasal-superior artefacts are observed in the densitometry Pentacam maps, and analysis shows no significant differences in their appearance between N or KC corneas. When analysing KC corneas, it was found that the cone positions are mostly on the temporal-inferior side of the cornea, opposite to the densitometry artefact NRSD trajectory. The analysis suggests that the corneal densitometry artefacts do not interfere with the KC area of pathology as it reaches its extreme in the opposite direction; therefore, weighting the densitometry map to increase the contribution of the inferior-temporal cornea and decreasing that of the superior-nasal area would improve the classification or identification of KC if densitometry is to be used as a KC metric.

PRESERFLO ™ MicroShunt versus trabeculectomy: 1-year results on efficacy and safety

PURPOSE

To compare the efficacy and safety of the PRESERFLO™ MicroShunt versus trabeculectomy in patients with primary open-angle glaucoma (POAG) after one year.

PATIENTS AND METHODS

Institutional prospective interventional cohort study comparing eyes with POAG, which had received the PRESERFLO™ MicroShunt versus trabeculectomy. The MicroShunt group was matched with the trabeculectomy group for age, known duration of disease, and number and classes of intraocular pressure (IOP) lowering medications to have similar conjunctival conditions. The study is part of the Dresden Glaucoma and Treatment Study, using a uniform study design, with the same inclusion and exclusion criteria, follow-ups and standardized definitions of success and failure for both procedures.

PRIMARY OUTCOME MEASURES

mean diurnal IOP (mdIOP, mean of 6 measurements), peak IOP, and IOP fluctuations.

SECONDARY OUTCOME MEASURES

success rates, number of IOP lowering medications, visual acuity, visual fields, complications, surgical interventions, and adverse events.

RESULTS

Sixty eyes of 60 patients, 30 in each group, were analyzed after 1-year follow-ups. Median [Q25, Q75] mdIOP (mmHg) dropped from 16.2 [13.8-21.5] to 10.5 [8.9-13.5] in the MicroShunt and from 17.6 [15.6-24.0] to 11.1 [9.5-12.3] in the trabeculectomy group, both without glaucoma medications. Reduction of mdIOP (P = .596), peak IOP (P = .702), and IOP fluctuations (P = .528) was not statistically significantly different between groups. The rate of interventions was statistically significantly higher in the trabeculectomy group, especially in the early postoperative period (P = .018). None of the patients experienced severe adverse events.

CONCLUSION

Both procedures are equally effective and safe in lowering mdIOP, peak IOP and IOP fluctuations in patients with POAG, one year after surgery.

CLINICAL TRIAL REGISTRATION

NCT02959242.

Influence of eye tilt on corneal densitometry

PURPOSE

To investigate whether Pentacam densitometry readings are affected by corneal tilt.

METHODS

In a prospective study, the right eyes of 86 healthy participants aged 42.8 ± 20.0 years (range 18-79 years) were imaged using Scheimpflug tomography. Elevation maps were exported to calculate corneal tilt using custom-made software, and densitometry readings were acquired directly from the corneal densitometry analysis add-on to the standard software Oculus Pentacam HR. Simple mediation analysis was applied to study age as a confounding factor in the correlation between corneal tilt and corneal densitometry.

RESULTS

Corneal tilt and corneal densitometry are not independent from one another because age is significantly correlated with both corneal tilt (r = 0.50, p < 0.001) and corneal densitometry (r = 0.91, p < 0.001). Only 3.8% of the correlation between tilt and densitometry operates directly, while the remaining 96.2% depends on age.

CONCLUSIONS

Corneal tilt plays a role in corneal densitometry readings, even though the interaction is strongly influenced by age. Age is a well-known factor in densitometry readings that should be taken into consideration when interpreting Scheimpflug densitometry.

PRESERFLO™ MicroShunt versus trabeculectomy: first results on efficacy and safety

PURPOSE

To report efficacy and safety outcomes of the PRESERFLO™ MicroShunt compared with trabeculectomy, the current gold-standard treatment for advanced glaucoma, in the early and intermediate postoperative period.

METHODS

Institutional prospective interventional cohort study of primary open-angle glaucoma (POAG) patients scheduled for the PRESERFLO™ MicroShunt. The comparison group were POAG patients who had had received trabeculectomy and were matched for age, known duration of disease, number and classes of intraocular pressure (IOP)-lowering medications to ensure a similar conjunctival condition. The study is part of the Dresden Glaucoma and Treatment Study (DGTS), was not randomized, but used a uniform study design, with the same inclusion and exclusion criteria as well as standardized definitions of success and failure.

MAIN OUTCOME MEASURES

mean diurnal IOP (mdIOP, mean of 6 measurements), diurnal peak IOP, diurnal IOP fluctuations, glaucoma medical therapy, success rates, visual acuity, visual fields, surgical complications and interventions, and severe adverse events.

RESULTS

Fifty-two eyes of 52 patients, 26 in each group, were analysed. At 6 months, median [Q25, Q75] mdIOP was 10.8 [9.5-12.2] mmHg in the microshunt and 10.3 [7.6-11.8] mmHg in the trabeculectomy group. Reduction in mdIOP (p = 0.458), peak diurnal IOP (p = 0.539), and median diurnal fluctuation (p = 0.693) was not statistically significantly different between groups. The rate of interventions was statistically significantly higher in the trabeculectomy compared with the microshunt group (p = 0.004). None of the patients experienced severe adverse events.

CONCLUSION

Both procedures are equally effective and safe in lowering mdIOP in patients with POAG. Because the microshunt is less invasive with less follow-up and interventions needed postoperatively, it might be recommended earlier in the treatment of glaucoma.