Differential impact of prostaglandin analogues on agreement of intraocular pressure measurements obtained by Goldmann applanation, rebound, and noncontact tonometry

Background To evaluate the effect of topical prostaglandin analogues on agreement of IOP measurements obtained by Goldmann applanation tonometry (GAT), rebound tonometry (RBT), and noncontact tonometry (NCT) in eyes with primary open- angle glaucoma (POAG). Methods Intraocular pressure measurements were obtained using GAT, RBT, and NCT in patients with POAG with or without prostaglandin analogues. The agreement between each tonometry was analysed using Bland-Altman analyses in those with or without prostaglandin analogues. The effect of average IOP on IOP differences was also evaluated. Results Among a total of 86 subjects included in the study, 44 patients were using prostaglandin analogues. The difference in IOP measured by GAT and RBT was marginally greater in those with (GAT-RBT: − 0.94 ± 1.63 mmHg) prostaglandin analogues than in those without (− 0.33 ± 1.22 mmHg, P = 0.06). The difference in IOP measured by GAT and NCT was significantly greater in the prostaglandin group (GAT-NCT: 2.40 ± 2.89 mmHg) than in the group without prostaglandin analogues (0.41 ± 1.63 mmHg, P < 0.01). While there was no significant relationship between the average of all tonometries and the difference between tonometries in those without prostaglandin analogues, both RBT and NCT underestimated IOP relative to GAT at higher IOP in those using prostaglandin analogues. Conclusion Intraocular pressure measured by RBT and NCT was similar to that measured by GAT in those without prostaglandin analogues. RBT overestimated and NCT underestimated IOP compared to GAT in those using prostaglandin analogues.

Evaluation of Intraocular Pressure and Other Biomechanical Parameters to Distinguish between Subclinical Keratoconus and Healthy Corneas

(1) Purpose: To assess the main corneal response differences between normal and subclinical keratoconus (SCKC) with a Corvis® ST device. (2) Material and Methods: We selected 183 eyes of normal patients, of a mean age of 33 ± 9 years and 16 eyes of patients with SCKC of a similar mean age. We measured best corrected visual acuity (BCVA) and corneal topography with a Pentacam HD device to select the SCKC group. Biomechanical measurements were performed using the Corvis® ST device. We carried out a non-parametric analysis of the data with SPSS software (Wilcoxon signed rank-test). (3) Results: We found statistically significant differences between the control and SCKC groups in some corneal biomechanical parameters: first and second applanation time (p = 0.05 and p = 0.02), maximum deformation amplitude (p = 0.016), highest concavity radius (p = 0.007), and second applanation length and corneal velocity ((p = 0.039 and p = 0.016). (4) Conclusions: Our results show that the use of normalised biomechanical parameters provided by noncontact tonometry, combined with a discriminant function theory, is a useful tool for detecting subclinical keratoconus.

First Line of Defense in COVID-19: Masks in Clinical Practice

The current evidence suggests that masks are efficacious in limiting the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV2). Although cloth masks are effective in outdoor environments, there is a consensus about the requirement of N95 masks or respirators when working in close proximity to patients who may be asymptomatic carriers, specifically in ophthalmology clinics, where slit-lamp examinations, noncontact tonometry, and other procedures place the physicians and patients in close proximity with each other. In this report, we review the available evidence regarding the efficacy of different types of masks in clinical practice in ophthalmology.

Unilateral lattice corneal dystrophy in a young female: A unique case report

Background: Unilateral lattice corneal dystrophy is a rare entity. Objective: To highlight the evidence of unilateral lattice corneal dystrophy in a young female. Case: A young 28 years old female presented to the outpatient department of Ophthalmology with slowly progressive diminution of vision in left eye for one month. On ophthalmological examination best corrected visual acuity (BCVA) was 20/20 and 20/40 with refractive error of plano and -0.75D Cyl @30 for right and left eye respectively. Ocular examination of right eye was unremarkable. On slit lamp examination, left eye showed multiple radial lattice lines in branching spider like pattern in the temporal cornea with pupillary margin involvement. The lattice pattern was confined to anterior to midstroma of the cornea with intact epithelium and unremarkable endothelium. The lesions did not involve the limbus. These lattice lines were prominent on retroillumination. In temporal quadrant near pupillary margin a small radial nebulomacular corneal opacity was seen without any corneal vascularisation or edema. The anterior chamber was deep and quiet. Corneal sensations were markedly reduced. Intraocular pressure was 10 and 12mmHg for right and left eye respectively with noncontact tonometry. Fundus examination was unremarkable. Family history and systemic history was negative. Optical coherence tomography(OCT) showed hyperreflective material in midstoma confirmed the diagnosis of unilateral lattice corneal dystrophy(LCD) with an apparently healthy fellow eye.

The impact of silicone hydrogel contact lenses on the measurement of intraocular pressure using non-contact tonometry

Background/Aim. Measurement of intraocular pressure (IOP) over therapeutic silicone hydrogel soft contact lenses by a non-contact method of tonometry could be applied in opthalmologic practice but the results obtained are still controversial. The aim of this study was to evaluate the effect of spherically designed silicone hydrogel soft contact lenses and their power on values of IOP measured by using a noncontact tonometry method. Methods. We measured IOP with and without spherical silicone hydrogel soft contact lenses on 143 eyes of 80 subjects who did not have any ocular or systemic diseases. Results. The Wilcoxon statistical analysis test for ranking average values of IOP measured on 143 eyes over a spherical silicone hydrogel soft contact lenses showed significantly higher values compared to those measured with no contact lenses (15.81 ? 3.46 mm Hg vs 14.54 ? 3.19 mm Hg; respectively; Z = -5.224, p = 0.001). Refractive power analysis of the contact lenses of -9.00D to +6.00 D showed a significant difference of IOP in the range from 0.00D to -6.00D. Conclusion. Non-contact tonometry is not an accurate method of IOP measuring over spherical silicone hydrogel soft contact lenses which belong to therapeutic contact lenses.