Diurnal variation in central corneal thickness and intraocular pressure in eyes with pseudoexfoliation syndrome without glaucoma

Unexpected findings: loss of corneal endothelial cells in Uygur patients with exfoliation syndrome

PURPOSE

This study aimed to investigate anterior segment parameters in patients with exfoliation syndrome (XFS) and exfoliation glaucoma (XFG).

METHODS

The study adopted a retrospective case series design, involving a total of 56 patients (112 eyes) with unrelated XFS/XFG (XFS: 26 patients/60 eyes; XFG: 30 patients/44 eyes) and 100 age-related cataract cases as the control group (200 eyes). The participants were evaluated at the ophthalmology department of the First Affiliated Hospital of Xinjiang Medical University. Clinical data, including eye axial length, anterior chamber depth, white-to-white distance, central corneal thickness, and corneal endothelial cell density (ECD), were collected for statistical analysis.

RESULTS

ECD exhibited a significant difference between the XFS/XFG and age-related cataract groups (P < 0.001), while the remaining indexes did not show statistical differences (P > 0.05). Ocular parameters in patients with XFS and XFG were distinct from those in age-related cataract cases, with consistent results. Notably, there were no statistically significant differences between XFS and XFG patients.

CONCLUSIONS

ECD is reduced in XFS/XFG patients compared with age-related cataract subjects. It is crucial to remain vigilant to enhance surgical safety in XFS/XFG patients and prevent complications proactively.

Retinal Nerve Fiber Layer and Ganglion Cell Complex Thickness in Adult Children of Patients With Pseudoexfoliation Glaucoma

PRCIS

The adult children of patients with pseudoexfoliation glaucoma (PXG) had universally lower retinal nerve fiber layer (RNFL) thickness and ganglion cell complex (GCC) thickness values compared with individuals with a negative family history of PXG.

PURPOSE

This study aimed to evaluate RNFL and GCC thicknesses in the adult children of individuals with PXG compared with people without a parental history of PXG.

MATERIALS AND METHODS

This cross-sectional observational study included 40 eyes of 40 adults with confirmed parental history of PXG and 40 eyes of 40 healthy adults with no parental history of PXG. RNFL and macular GCC thicknesses were measured by spectral-domain optical coherence tomography (Nidek RS-3000 Advance) and compared between the groups. All subjects also underwent visual field testing (program 30-2 of the Humphrey Field Analyzer), and their mean deviation and pattern SD values were compared.

RESULTS

Compared with adults without parental PXG, those with a parental history of PXG had significantly lower RNFL thickness overall (mean 98.2 vs 109.5 µm) and in all quadrants (inferior, superior, nasal, and temporal) ( P <0.001 for all). They also had significantly lower GCC thickness overall (mean 97.9 vs 109.4 µm) and in both hemispheres (superior and inferior) ( P <0.001 for all). There was no significant difference between the groups in terms of mean deviation or pattern SD values ( P >0.05).

CONCLUSION

PXG in a parent was associated with significantly thinner RNFL and GCC compared with those with no history of PXG in a parent. Longer follow-up and prospective controlled clinical studies are needed to evaluate whether these findings may serve as an early indicator of glaucoma in the adult children of known PXG patients.

Diurnal variation of central corneal thickness and intraocular pressure in eyes with pseudoexfoliation

Purpose:

Pseudoexfoliation syndrome (PXS) is an age related microfibrillopathy characterized by deposition of whitish flaky material over various ocular tissues. PXS eyes are known to have thinner corneas and thus can lead to an underestimation in intraocular pressure measurement. The purpose of this study was to find if there is any variation in central corneal thickness and intraocular pressure in PXS eyes and if there was any relationship between them.

Methods:

A prospective observational study was done on 141 eyes of 85 patients with PXS without glaucoma between November 2015 to April 2017 in the department of Ophthalmology in a tertiary hospital. CCT and IOP were measured by a handheld ultrasonic pachymeter (DGH Technology INC. Pachette 2, USA) and Goldmann applanation tonometer respectively at 4 different times during office hours.

Results:

A significant reduction of about 10 μm in mean CCT and 1.4 mmHg in mean IOP was noted over the 4 sessions which was statistically significant (P < 0.001). A significant correlation exists between IOP and CCT in PXS eyes at all times during the day (P < 0.001).

Conclusion:

The CCT measurements show significant thinning throughout the day, similar drop in IOP was also noted. Our study shows that there is a significant correlation between diurnal variation of CCT and IOP. Hence, it is prudent to measure CCT along with IOP at all times.

Limbal rebound tonometry: clinical comparisons and applications

PURPOSE

The accuracy of contact tonometry may be compromised in cases with disorders affecting central corneal bio-mechanical properties. This study examined the reliability of rebound tonometry (RT) on the area of corneo-scleral limbus, instead of the conventional central corneal area, and the correlation of findings with ocular biometric parameters.

METHODS

This is a prospective cross-sectional study performed at the Department of Ophthalmology of the University Hospital of Heraklion, in Crete, Greece. Consecutive cataract surgery candidates without concomitant ocular pathology, apart from cataract, were included. RT was performed on the central cornea (central RT, CRT) as well as on the limbus and scleral spur area (limbal RT, LRT). Findings were correlated with Goldmann applanation tonometry (GAT) as well as axial length (AL), central corneal thickness (CCT), and corneal curvature (CC) measurements.

RESULTS

LRT readings were significantly correlated with central CRT as well as with GAT readings, whereas respective correlations with other parameters examined were not statistically significant.

CONCLUSIONS

LRT may be used as an alternative tool in clinical practice to determine intraocular pressure when conventional devices and techniques might be inadequate or unreliable.

The Effect of Pseudoexfoliation and Pseudoexfoliation Induced Dry Eye on Central Corneal Thickness

PURPOSE/AIM OF THE STUDY

The aim of this study is to investigate the effect of pseudoexfoliation (PEX) and PEX-induced dry eye on central corneal thickness (CCT).

MATERIALS AND METHODS

This cross-sectional study consists of total 270 eyes of 135 patients (67 females, 68 males) in total. After excluding the PEX (-) 32 eyes with PEX in the other eye, totally 130 eyes in PEX (-) group and 108 eyes in the PEX (+) group were included in the study. The PEX (+) group was regrouped as PEX syndrome (80 eyes of 50 patients) and PEX glaucoma (28 eyes of 20 patients).

RESULTS

In the PEX (-) group, the mean Schirmer test result was 12 ± 4 mm (4-25 mm), in the PEX syndrome group 10 ± 4 mm (4-22 mm), in the PEX glaucoma group 9 ± 3 mm (4-15 mm). The difference among the PEX (-) group, the PEX syndrome and the PEX glaucoma groups was statistically significant (p < 0.001, p < 0.001, respectively). In the PEX (-) group, the mean tear break up time test result was 11 ± 2 s (5-16 s), in the PEX syndrome group 8 ± 3 (3-16 s), in the PEX glaucoma group 8 ± 3 s (5-15 s). Mean CCT result was 544 µm in the PEX (-), 521 µm in the PEX syndrome group and 533 µm in the PEX glaucoma group. The difference among the PEX (-) group, the PEX syndrome and the PEX glaucoma groups was significant (p < 0.001, p = 0.030, respectively). There was a significant (+) correlation between intraocular pressure and CCT in the eyes with PEX (r = 0.307, p = 0.001). However, there was no statistically significant correlation between CCT, Schirmer and tear break up time tests in the eyes with PEX.

CONCLUSIONS

PEX material can cause decrease in tear film secretion and disturb tear film stability. There is no effect of PEX-induced dry eye on CCT. Lower CCT values in the eyes with PEX material may be a result of decrease in corneal stromal cell density. Moreover, higher CCT values may be because of decreased endothelial cells in PEX glaucoma patients.