Goldmann Tonometry and Corneal Biomechanics

Glaucoma is the second cause of irreversible blindness in the world. Intraocular pressure (IOP) is a recognized major risk factor for the development and progression of glaucomatous damage. Goldmann applanation tonometry (GAT) is internationally accepted as the gold standard for the measurement of IOP. The purpose of this study was to search for correlations between Goldmann tonometry and corneal mechanical properties and thickness by means of in vitro tests. IOP was measured by the Goldmann applanation tonometer (GIOP), and by a pressure transducer inserted in the anterior chamber of the eye (TIOP), at increasing pressure levels by addition of saline solution in the anterior chamber of enucleated pig eyes (n = 49). Mechanical properties were also determined by inflation tests. The GAT underestimated the real measurements made by the pressure transducer, with most common differences in the range 15–28 mmHg. The difference between the two instruments, highlighted by the Bland–Altman test, was confirmed by ANOVA, normality tests, and Mann–Whitney’s tests, both on the data arranged for infusions and for the data organized by pressure ranges. Pearson correlation tests revealed a negative correlation between (TIOP-GIOP) and both corneal stiffness and corneal thickness. In conclusion, data obtained showed a discrepancy between GIOP and TIOP more evident for softer and thinner corneas, that is very important for glaucoma detection.

Study of the Prevalence of Glaucoma in Kazakhstan

Background Glaucoma is one of the leading causes of permanent visual disability around the world. However, the available literature lacks data on the prevalence of glaucoma in Central Asia, particularly in the Republic of Kazakhstan. Objective The study was aimed at assessing the prevalence of glaucoma in the population of the Republic of Kazakhstan over 40 years old in 2019. Methods A retrospective study was based on the analysis of the results of glaucoma screenings in 171 832 patients over 40 years old living in Kazakhstan (in 14 counties). Glaucoma cases were confirmed by Goldmann tonometry, fundus photography, and visual field testing. Demographic indicators, territorial differences, and hereditary predisposition were studied and analysed. In addition, blood pressure was measured. Results Of 171 832 patients examined, 452 with verified glaucoma were identified. The average age of the patients was 63.9 ± 9.4. In rural areas, the prevalence of glaucoma was higher compared to the urban population. The overall prevalence of glaucoma among people over 40 years old was 2.37 ± 0.17. The prevalence of glaucoma among women was higher than for men, with an indicator of 1.91 (95% CI relative risk 1.78 – 2.03) (p < 0.05). The highest prevalence was found in the 71 – 75 age group [equals to 14.2% (95% CI 11.7 – 19.9)], with a statistically significant difference (p < 0.05). The highest prevalence of glaucoma was observed in the group of people with a hereditary predisposition, with an indicator of 14.7% (95% CI 0.6 – 1.9) (p < 0.05). Among all patients with concomitant arterial hypertension (n = 90, 19.9%), women (60%) compared with men (40%) had a 2.4% higher risk of glaucoma morbidity (95% CI 1.2% − 3.8%). Conclusion This study provides updated information on the prevalence of glaucoma in Kazakhstan. The results obtained confirm that the increase in the prevalence of glaucoma in Kazakhstan is directly proportional to the increase in the patientsʼ age. These results showed the importance of screening for a timely diagnosis, especially for patients with high risk factors such as hereditary predisposition. Moreover, the results indicate that the early detection of systemic hypertension and increased intraocular pressure can be used for the prevention of undesirable outcomes such as an irreversible blindness.

Switching to intravitreal fluocinolone acetonide implant for refractory diabetic macular edema: 12- and 24-month results

Purpose: To report visual and anatomical outcomes of chronic/refractory diabetic macular edema (DME) treated with intravitreal fluocinolone acetonide implant. Setting: Retrospective, one arm, multicentric study. Method: Between 2013 and 2018, 27 consecutive eyes of 25 patients with chronic/refractory DME were treated with a fluocinolone acetonide intravitreal implant. Best registered visual acuity (BRVA), central retinal thickness (CRT), and Goldmann tonometry intraocular pressure (IOP) were assessed at 12 and 24 months. The need for IOP lowering treatment as well as top-up therapy during the follow-up were also assessed. Results: The duration of DME prior to treatment in our study was 54 ± 24 months. The baseline mean BRVA of 0.7 ± 0.34 logMAR improved to 0.5 ± 0.3 ( p = 0.01) at 12 months and 0.46 ± 0.3 ( p = 0.04) at 24 months. At 12 months, BRVA improved in 14 eyes (52%), stabilized in 5 eyes (20%), and decreased in 3 eyes (11%). At 24 months, BRVA improved further in 6 eyes (24%), stabilized in 3 eyes (12%), and decreased in 6 eyes (24 %). Mean CRT decreased from 497 ± 176 to 349 ± 186 μm at 12 months ( p = 0.0005) and to 267 ± 104 μm at 24 months ( p = 0.001). Only five eyes required additional treatment for DME and only three eyes required treatment for raised IOP. Discussion: Our results show that the visual and the anatomical improvements achieved by a single injection of a fluocinolone acetonide implant were maintained up to 24 months with minimal additional therapy even in eyes with a long and heavy history; however, IOP monitoring remains essential.

Correlation between changes in intraocular pressure and refractive error indices post Cataract Surgery

Objective: To evaluate the correlation between refractive errors and change in intraocular pressure in patients undergoing cataract surgery. Methods: This interventional retrospective case study was carried out from September 2018 to April 2019 at Bodla Eye Care and Multan Medical and Dental College, Multan. A total of 127 eyes were recruited in the study among which six were excluded. Out of remaining 121, 53 eyes were emmetropes, 41 were mild myopes and 27 were high myopes. Single surgeon performed the procedure. Pre-operative investigations of IOP and refractive error were done by goldmann tonometry and auto refractometry. IOP was reviewed at day 1, 7, 14 and 28 post cataract surgeries. Results: Out of 121 eyes, 53 eyes were emmetropes, 41 were mild myopes and 27 were high myopes, who underwent phacoemulsification. There was an elevation of 2-3mm Hg at Day-1, in emmetropes and mild myopes, and further on, a constant drop was noticed on follow ups. In high myopes a significant fluctuation of IOP was noted in first fourteen days followed by an unremarkable gradual decline afterwards. Conclusion: Cataract surgery helps lowering the IOP in patients with refractive errors. Mild myopic and emmetropic patients showed a linear swift pattern while high myopes presented instable and gradual reduction in IOP. A total decrease of 1-2mm Hg was seen at the end of the study depicting that relation between IOP and cataract surgery is insignificant. doi: https://doi.org/10.12669/pjms.36.3.1597 How to cite this:Bodla MA, Bodla AA, Moazzam A, Tariq N. Correlation between changes in intraocular pressure and refractive error indices post Cataract Surgery. Pak J Med Sci. 2020;36(3):---------. doi: https://doi.org/10.12669/pjms.36.3.1597 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.