Al-Basar International Journal of Ophthalmology

: 2017  |  Volume : 4  |  Issue : 4  |  Page : 93--98

Comparison of goldmann applanation tonometry measurements with and without fluorescein among adult sudanese glaucomatous and nonglaucomatous population 2018

Islam Elzein1, Mahgoub Saleem2,  
1 Department of Outpatient, Makkah Eye Complex, Sudan Eye Teaching Hospital, Khartoum, Sudan
2 Department of Ophthalmology, Faculty of Medicine, Al-Neelain University, Khartoum, Sudan

Correspondence Address:
Dr. Mahgoub Saleem
Department of Ophthalmology, Faculty of Medicine, Al-Neelain University, P. O. Box. 10139, Khartoum 11111


Background: Goldman applanation tonometry (GAT) is still the most accurate for measuring intraocular pressure (IOP). Usually, fluorescein eye drops are used in additional to topical anesthesia to gain the best visualization result. Objective: The main objective of the study is to compare the GAT values with and without fluorescein in adult Sudanese glaucomatous and nonglaucomatous population. Materials and Methods: In a cross-sectional hospital-based study, 400 patients were recruited from out patient's and glaucoma clinics at Makkah Eye Complex, Khartoum, in the period from December 2017 to January 2018. Different ages were classified into three groups, patients also classified into glaucoma (n = 200) and nonglaucoma (n = 200) patients, another classification according to gender. Then, IOP measurements with and without topical fluorescein were done by GAT. Results: Two hundred and sixteen (n = 216; 54%) were male and 184 (46%) were female, with an average age of 54.76 ± 24.5 years. Two hundred (50%) were glaucomatous, and the other 200 (50%) were nonglaucomatous. The average IOP with fluorescein was higher than without fluorescein by 13.1% (2.08 mmHg) and still was higher in comparison between non-Glaucomatous and glaucomatous with and without fluorescein up to 3. 41 mmHg (17.86%). Both results ± fluorescein and ± glaucoma were statistically significant (P = 0.000). There was a significant correlation between age and IOP values with fluorescein and between having glaucoma and IOP with fluorescein (P = 0.000), while there was nonsignificant correlation between sex and IOP measurements with fluorescein. Conclusion: There are statistically significant differences in IOP values by GAT either ± fluorescein or ± glaucoma. A significant correlation between age and IOP values either ± fluorescein or ± glaucoma were detected, but not to sex.

How to cite this article:
Elzein I, Saleem M. Comparison of goldmann applanation tonometry measurements with and without fluorescein among adult sudanese glaucomatous and nonglaucomatous population 2018.Albasar Int J Ophthalmol 2017;4:93-98

How to cite this URL:
Elzein I, Saleem M. Comparison of goldmann applanation tonometry measurements with and without fluorescein among adult sudanese glaucomatous and nonglaucomatous population 2018. Albasar Int J Ophthalmol [serial online] 2017 [cited 2021 Oct 28 ];4:93-98
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Perfect and Reliable[1] Intraocular pressure (IOP) measurement (Tonometry) is a very crucial process in screening and monitoring high risk glaucoma individuals, as IOP is the only modifiable risk factor for glaucoma progression at this time. The more popular ocular tonometer to measure the Intraocular pressure is the Goldmann applanation tonometer (GAT).[2] Tonometry is an important test in ocular examination in the evaluation of IOP, which can be carried routinely by different types of tonometers to measure IOP in patients at risk of glaucoma. GAT, although its reading can be influenced by some factors, like central corneal thickness, it remains the gold standard and the commonest accurate and acceptable technique.[3],[4] GAT tonometry is performed with and without topical flourescein drops, but having considered the complications of using fluorescein, such as burning sensation, allergic reaction, infection, its high costs and less availability, Ophthalmologists tend to perform it without flourescein;[5] especially in developing countries.

 Materials and Methods

After an ethical approval from the Makkah Research Center Ethical Committee, the current cross-sectional hospital-based clinical study was conducted at Makkah Tertiary Eye Complex (MEC), Khartoum, Sudan. A total of four hundred (n = 400) patients; including 200 glaucomatous and another 200 nonglaucomatous Sudanese males and females' patients; attending the General Ophthalmology Outpatient's and Glaucoma Clinics at MEC, Khartoum, Sudan; were included in the current study according to a predetermined simple randomization schedule. This was achieved through fixed 3 days/week scheduled visits; 1 fixed day to the general ophthalmology clinics and 2 fixed days to glaucoma clinic all through the study period from December 2017 to January 2018. Patients with corneal pathological disorders and pervious corneal surgery that may lead to poor intraocular pressure (IOP) measurements were excluded. The study was performed over a period of 2 months; December 2017–January 2018. The total studied eyes of the 400 patients were 797 eyes as 3 patients were one-eyed patients. All the selected candidates who fulfilled the inclusion criteria were interviewed and examined by the primary investigator. After well-informed consent from each of the 400 participants; standardized ophthalmic medical history and full slit-lamp (Haag-Streit Diagnostics-Slit-Lamp BQ 900/870 18./2014-11; HAAG-STREIT AG Gartenstadtstrasse 10 3098 Koeniz, Switzerland, biomicroscopic examination for anterior and then posterior segments with Double Aspheric 90 D VolK Non-Contact Lens (Manufactured by Volk Optical Inc., V90C; 7893 Enterprise Drive Mentor, OH 44060, USA) were considered and the collected variables were recorded in the predesigned “Data Collection Forms” at the time of examination. IOP was done by Goldmann applanation tonometer (GAT) (Haag-Streit Diagnostics-Applanation tonometer AT 900®/870 18 Edition/17, 2014-11; HAAG-STREIT AG Gartenstadtstrasse 10 3098 Koeniz, Switzerland mounted on Haag-Streit slit lamp. The IOP measurements were obtained after installing one drop of Alcaine topical ophthalmic anesthetic (Proparacaine as generic name; manufactured by Alcon, US,4039662A-975-12-04 1977-08-02 Alcon Laboratories, Inc.) in each eye of each participant; first without fluorescein then repeated with fluorescein to identify the differences. IOP was measured in both the eyes of 397 patients (794 eyes), the remaining 3 patients were found to be single-eyed patients, so the total number of the examined eyes were 797 eyes in the 400 participants. The study population was divided into three groups according to age, the first age group including patients from 20 up to 41 years age, 2nd from 41 to 60 years, and the 3rd one including those participants who were >60 years old [Figure 1]. These groups were also classified into glaucoma and nonglaucoma patients, then classified according to gender and reclassified according to: IOP measurements ± topical fluorescein. Data were statistically analyzed using the Statistical Package for the Social Sciences; (SPSS) for Windows, version 20 (Manufactured by IBM SPSS Inc. PASW Statistics for Windows, Version 20; 2011. SPSS Inc., Chicago, IL, USA). Results obtained were presented in tables and figures. Categorical variables were analyzed using frequencies and percentage. The confidence interval was 95% and the significant value was taken as P < 0.05. Mean, median, and mode were used to explain demographic variables.{Figure 1}


Four hundred (n = 400) Sudanese males and females were enrolled in the current study. Two hundred and sixteen (n = 216; 54%) of the patients were male, while 184 (46%) were female [Figure 2]. The average age of the whole participants was 54.76 ± 24.5 years.{Figure 2}

Two hundred (50%) were glaucomatous, and the other 200 (50%) were nonglaucomatous. The most frequent age group of the participants was between 41 and 60 years of age, which constitutes 273 (68.25%) of the study group. The next frequent group was >60 years old, which constitutes 90 (22.5%) patients. While the least frequent group was the youngest, age group from 21 to 40 years old that composed only of 37 (9.25%) patients [Figure 1]. Seven hundred and ninety-seven eyes from the 400 participants were subjected to IOP testing ± fluorescein; as 3 patients were found to be single-eyed patients, so the total number of the examined eyes was 797 eyes instead of 800 eyes. The mean IOP value without fluorescein was 13.77 mmHg; being lower by 2.08 mmHg (13.1%) to those IOP tonometry values when done with fluorescein to give mean IOP of 15.85 mmHg [Figure 3]. When using compare means T-test; the mean IOP value for right eyes (OD) in non-glaucoma patients when using fluorescein drops was 14.49 mmHg, whereas it was 17.65 mmHg in glaucoma patients when using fluorescein drops. The mean IOP measurements when using fluorescein drops for left eyes (OS) in nonglaucoma patients was 14.10 mmHg, while the mean IOP measurements was 17.17mmHg in glaucoma patients when using fluorescein drops [Table 1]a. The mean IOP value for OD in nonglaucoma patients without using fluorescein was 12.11 mmHg, whereas it was 15.84 in glaucoma patients. The mean IOP without using fluorescein for OS in nonglaucoma patients was 11.73, whereas it was 15.42 in glaucoma patients [Table 1]b. The average differences between nonglaucomatous and glaucomatous IOP values with and without fluorescein were 3. 41 mmHg [Table 1]a and [Table 1]b.{Figure 3}{Table 1}

There was statistically significant difference in IOP measurements when using fluorescein drops and not using fluorescein (P = 0.000). [Table 2] and [Table 3] showed statistically significant correlation between age and IOP measurements when using fluorescein, while [Table 4] showed a non-significant correlation between sex and IOP measurements with fluorescein. There is a significant correlation between having glaucoma and IOP measurements using fluorescein [Table 5]. [Table 6] showed the correlations between several variables included in the study.{Table 2}{Table 3}{Table 4}{Table 5}{Table 6}



IOP is determined by the balance between the rate of aqueous production and its outflow, the latter in turn related to factors that include the resistance encountered in the trabeculum and the level of episcleral venous pressure.[6],[7] The average IOP in the general population is around 16 mmHg on applanation tonometry, and range of about 11–21 mmHg. Two standard deviations (SD) to either side of the average has conventionally been accepted as normal, at least for a Caucasian population. IOP is measured by tonometer, the more popular and accurate tonometer is GAT.[2] Many factors can affect the readings of GAT such as the use of fluorescein,[8] correct GAT calibrations, age,[9] glaucoma, extra.

Many studies have compared IOP measurement with GAT without fluorescein and then using fluorescein.[10],[11] The current study evaluated 400 patients, 797 eyes the mean IOP with fluorescein for all patients was found to be 15.85 which is different significantly from the mean IOP without fluorescein 13.77. This result is different from a study done in Iran (on 2008 by S. Bamdad and his collegues)[12] evaluated 250 patients included all ages the result was that the mean IOP with and without fluorescein were 12.90 ±2.7 and 12.60±2.09 mmHg respectively.

They concluded that there are not any significant differences between measurement with and without fluorescein in contrary of the current one. The current study was similar to the study done by Arend N and his fellows (Arend N, 2014)[8] where they found significant Differences in the measurement results of GAT with and without fluorescein. A total of 400 eyes of 200 patients not known glaucoma were enrolled in this study, randomized into two groups. first measurement for the 1st group was without fluorescein then with fluorescein, vice versa for 2nd group, same examiner same slit lamp. Results showed that in both groups performing GAT without the application of fluorescein led to significantly lower measurements results, but it concludes also, no significant differences regarding patient age, astigmatism or reason for consulting, which is different from the current results, which showed that there is significant statistical correlation to the age. The current study revealed significant difference (2.08 mmHg) between IOP measurement with and without fluorescein this really deferent from Levy SN (2004)[11] study where he found the deference between both groups examined in his 100 eyes; with and without fluorescein using GAT, the result was that the mean IOP of non-fluorescein group was 0.5 mmHg less than fluorescein group, but if 1 mmHg is considered clinically relevant to therapy that difference is not statistically significant and they conclude that measurements without fluorescein are clinically acceptable. Another older odd study held in USA 1981 by Bright DC and colleagues[13] examined 100 patients with GAT without and with fluorescein; it was found that average difference between reading with fluorescein and without was very big as 7.01 mmHg which was far from the current one where the deference was only 2.08 mmHg. Although the above Bright DC and colleagues[13] found that tonometry reading without fluorescein were lower than readings with fluorescein, in line with this current study. No recent studies showed that sex has any significant correlation with IOP measurement.


GAT, remain the most suitable and reliable device, and it is the international gold standard for measuring IOP. There is significant difference in IOP measurement using GAT when apply fluorescein and not apply it, equal to 2.1 mmHg; this may lead to serious consequences in border line cases. Age showed significant correlation to IOP measurement whereas sex did not show any correlation.


Need for more clinical studies to search for possible causes of significant difference in IOP measurement by GAT using fluorescein and not using fluorescein.Further clinical trials are required to investigate more influence of fluorescein regarding other variables like, refractive status, age and sex on IOP measurement.

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Conflicts of interest

There are no conflicts of interest.


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