Ophthalmology Pakistan

A comparative study of stereoacuity in against the rule and oblique astigmatism.

Nimra Asif, Muhammad Anwar Awan, Bareera Aslam — Thu, 21 Sep 2023 00:00:00 +0000

OBJECTIVE: To measure and compare the stereopsis level among the persons with against-the-rule and oblique astigmatism using Lang I and Lang II tests.

METHODS: Informed consent was obtained from each patient both in verbal and written form. A proforma was filled at the time of examination. Visual acuity was checked on Snellen chart which was then converted to log MAR values. The type and amount of astigmatism was measured by performing refraction subjectively using trial lenses. Individuals having cylindrical value at the axis of 70-120 degrees were considered to have against-the-rule astigmatism while individuals having cylindrical value at the axis of 20-60 degrees and 130-160 degrees were considered to have oblique astigmatism. Lang I and Lang II are performed for detailed or fine measurement of stereopsis. The sample size was 36 with a confidence level of 95% is taken and the study is conducted in the College of Ophthalmology and Allied Vision Sciences (COAVS), LAHORE. Data was entered and analyzed using a statistical package for social sciences (SPSS version-25.00). Mann-Whitney test was applied to compare the results. P-value ≤0.05 was considered significant.

RESULTS: A total of 36 individuals were included in this study and out of 36 individuals 18 individuals had against-the-rule astigmatism and remaining 18 had oblique astigmatism. Stereoacuity was measured in these two groups of astigmatism. Subjective refraction showed that the visual acuity of most of the individuals in right eye was equal to 6/36 and in left eye 6/24. And a greater number of individuals had plano spherical power in both eyes and cylindrical power of -0.50 DC in both eyes. The p-value of visual acuity, spherical readings, cylindrical readings showed that these all were insignificant in our results as p-value is >0.05. The results of Lang I test showed that large number of individuals (52.8%) did not respond to this test while Lang II test showed that (41.67%) individuals did not respond to this test means the stereopsis was absent in them. Shapiro Wilk test was used to check the normality of data and according to this test the p-value is ≤0.05 (p<0.01). It means that our data is not showing normality therefore we apply non-parametric tests. Then the p-values were find using Mann Whitney test (non-parametric test). And it showed that the p-value in Lang I test is (p=0.006) is ≤0.05. Similarly, the p-value for Lang II is (p=0.034) is also ≤0.05. As the p-values in Lang I and Lang II are ≤0.05 it means that the results are significant for this study.

CONCLUSION: Oblique astigmatic individuals had significantly poor stereopsis as compared to against-the-rule astigmatic individuals
using Lang I and Lang II tests.

KEYWORDS: Astigmatism, Against the rule astigmatism, Oblique astigmatism, Stereopsis, Stereoacuity, Lang I, Lang II, Visual acuity.

Assessment of visual functions in motorway drivers.

Asif Ali, Arif Hussain, Ameer Hamza, Basharat Hussain — Thu, 21 Sep 2023 00:00:00 +0000

OBJECTIVE: To assess the visual functions of motorway drivers who drive regularly on the motorway in Lahore in order to avoid road
accidents.

METHOD: A cross-sectional study has been done to assess the visual functions of motorway drivers using a proforma study design. Data of 70 drivers were taken using different charts and proforma. Visual acuity was recorded on the Snellen chart, colour vision by Ishihara chart, contrast sensitivity by Pelli Robson Chart, and visual field by Confrontation method. Glare sensitivity was excluded.

RESULTS: 70 drivers were enrolled in this study. 30 to 60 years aged drivers were included. All the participants were males. Data was
collected by using proforma and performing practical tests. The mean age was 44 years and the mean driving experience was 9 years. 20 (28.6%) drivers had defected visual acuity, 16 (22.8%) drivers had abnormal contrast sensitivity, 22 (31.4%) drivers had defected colour vision, 7 (10%) drivers had defected visual field. 5 (7.1%) drivers had positive hypertension history and 5 (7.1%) drivers were diabetic. History of diabetes and hypertension were recorded as these have significant effects on human eyes.

CONCLUSION: Visual functions are more defected in older drivers than in younger drivers. Impairment of visual acuity and visual field are the major cause of problem with minor effect of other components of visual functions.

KEYWORDS: Motorway drivers, Visual functions, Diabetes mellitus, Hypertension, Accidents, Awareness, Medical attention.

The relationship between symptomatic dry eye and occupation.

Shazia Mushtaq, Dr. Rashida Riaz — Thu, 21 Sep 2023 00:00:00 +0000

OBJECTIVE: To check the relationship between symptomatic dry eye disease and different occupations. Environmental factors play an
important etiological role in dry eye.

METHOD: A cross-sectional survey was done on 174 subjects presenting in Mayo Hospital Eye Outdoor department with the help of a selfdesigned, pre-tested questionnaire based on the symptoms of dry eye disease. Questionnaire was used to assess the relationship between occupation and dry eye disease. The study included participants of both genders of different age groups. Verbal consent was taken by every respondent before being interviewed. SPSS 21 software was used for data analysis.

RESULTS: Use of VDTs, sedentary occupations with indoor working environments with air conditioners, occupations demanding prolonged use of computers, working in the presence of germs, toxins, chemicals and climatic factors that effects the eye in the adverse manner were found to be at highest risk of dry eye disease. While occupations which involved more physical movement, social working, less digital working and government employees showed lowest risk of DED. Subjects with occupations like accounting, graphic designing, managers etc. showed highest prevalence of symptomatic dry eye disease. And medical representatives, office boys, government employees showed lowest prevalence of dry eye disease.

CONCLUSION: It was found that the people who had indoor occupations showed high prevalence of symptomatic dry eye disease and
people who had outdoor and physically active occupations were at a lower risk of developing dry eye disease.

KEYWORDS: Symptomatic dry eye disease, VDTs, occupation, indoor and outdoor occupations.

Correlation of mean retinal nerve fibre layer (RNFL) thickness with type of refractive error.

Najamul Hassan, Shaista Usman, Ruhullah, Gul Nasreen, Kabir Hussain — Thu, 21 Sep 2023 00:00:00 +0000

OBJECTIVE: To evaluate the mean retinal nerve fiber layer (RNFL) thickness in individuals with myopia, hyperopia, and astigmatism and
correlate it with specific refractive error.

METHOD: This comparative cross-sectional study was performed on type of refractive error, included Myopia, Hyperopia, and
Astigmatism. Sixty six eyes of thirty three subjects comprising twenty four eyes with myopia, twenty eyes with hyperopia and twenty two eyes with astigmatism were examined. Optical Coherent Tomogram (OCT) was used to measure RNFL thickness. Data were analyzed with SPSS-25.

RESULTS: Mean RNFL thickness in myopic eye was (92.62 ±8.43) with (SE: -1.00to -7.50), Mean RNFL thickness in Hyperopic eye was (101.25 ± 8.82) with (SE: +0.75 to +3.75). Mean RNFL thickness in Astigmatic eye was (96.95 ±8.23) with (Cyl:-1.00 to -4.00 at 180). The difference between mean RNFL thickness for myopia, hyperopia and astigmatism was statistically significant (One way-ANOVA, f=8.2689, p= 0.0019). There was positive moderate correlation between average RNFL thickness and refractive error (r=0.451). There was very weak positive correlation of average RNFL thickness between myopia (r=0.283), and hyperopia (r=0.118) respectively and positive moderate correlation with astigmatism (r=0.564).

CONCLUSION: RNFL is significantly associated with type of refractive error being thickest for hyperopia and thinnest for myopia. Careful clinical interpretation is a must especially in myopia to avoid misdiagnosis with glaucoma.

KEYWORDS: RNFL, Myopia, Hyperopia, Astigmatism

Contrast sensitivity function and photostress recovery time in glaucoma suspects.

Nishat Wali, Dr. Samman Ali; Sabahat Zubair, Maryam Sajid — Thu, 21 Sep 2023 00:00:00 +0000

OBJECTIVE: The aim of this study was to assess contrast sensitivity function and photostress recovery time in Glaucoma suspects and to find the association of raised IOP with Contrast sensitivity function (CSF) and Photostress recovery time (PSRT).

METHODS: In this cross sectional observational study, 97 glaucoma suspects were included. The suspects were selected from regular
visitors of the outpatient department of Ophthalmology Mayo Hospital Lahore. The ethics board of the University approved the study
protocol. The principles of Declaration of Helsinki were followed in the study. All the subjects provided written informed consent. CS was measured monocularly using the Pelli-Robson chart at distance of 1 m with standard room illumination and scores were noted for at least two letters identified by the suspects with least contrast. PSRT was tested using distant direct ophthalmoscope. One sample t-test was used to analyze the data and compare means of CSF and PSRT with normal values mentioned in literature. Pearson correlation was applied to find the relation of variables.

RESULTS: The analysis included 97 glaucoma suspects. Mean age was 49.98 ± 7.12 years, and 41% were men. Mean CSF was 0.92 ±0.10
(p<0.000). Similarly, PSRT was 59.32seconds (p<0.000). The correlation of IOP with CSF was r= -0.435(p<0.000) and IOP with PSRT was r =
0.224 (p=0.028).

CONCLUSION: The study results showed that Contrast sensitivity is reduced and Photostress recovery time is delayed in glaucoma suspects. The raised IOP also showed significant association with CSF and PSRT. This result is a useful psychophysical indicator and could give an important clinical understanding of the early changes before glaucomatous optic disc and defected visual field are appeared.

KEY WORDS: Glaucoma, Glaucoma suspects, Contrast sensitivity.

Association of caffeine intake with pupil size and visual acuity.

Sabahat Zubair, Arif Hussain; Nishat Wali, Maryam Sajid — Thu, 21 Sep 2023 00:00:00 +0000

OBJECTIVE: This research was done to check the association of dietary caffeine intake with pupil size and visual acuity. As caffeine itself is an autonomic stimulant drug and pupil size is controlled by smooth muscles of iris, stimulated by autonomic nervous system. Pupil size changes visual acuity by altering ocular aberrations.

METHODS: Caffeine consumers who drink coffee at-least 3 times per week or tea at-least 2 times per day were included in this comparative cross-sectional study. After taking their general history, pupil size was measured both in dim illumination and bright light conditions with the help of mm ruler and pen torch. Visual acuity for distance and near was assessed using logMAR (E-chart) and near acuity chart respectively. Mean values of dVA, nVA, PS(dim) and PS(illuminated) of caffeine consumers were compared to standard values of dVA(0.00) in logMAR , nVA(N=6.00), mean pupil size under dim light (6.00mm) and mean pupil size under bright light (3.00mm) respectively using One-Sample t Test.

RESULTS: Distance visual acuity (dVA) of caffeine consumers was significantly different from standard logMAR value(0.00) as p -value was 0.000, near visual acuity (nVA) of caffeine consumer was also significantly different from standard value (6.00) as p-value was 0.000. Similarly, mean pupil size under dim and bright light conditions of caffeine consumers were significantly different from mean of normal value of pupil diameter under dim and bright and light conditions respectively and p values were 0.001 and 0.000 for dim light pupil size and bright light comparisons with normal values mean respectively.

CONCLUSION: In habitual caffeine consumers near and distance visual acuity and pupil size for both dim and bright light conditions were different from the standard value of visual acuity and pupil size present in literature.

Artificial Intelligence in Ophthalmology

Imran Ahmad — Thu, 21 Sep 2023 00:00:00 +0000

This is the era of Artificial intelligence (AI) and it is rapidly taking control of all spheres of life including medicine and healthcare. Ophthalmology is one of the departments of medicine that makes best use of cutting edge technologies. It is, therefore, no surprise that AI has shown tremendous potential to enhance the accuracy and efficiency of ophthalmic diagnostics, treatment, and research by employing advancements in software and computer based algorithms.
One of the most significant applications of AI in ophthalmology is in the field of image analysis. Imaging techniques such as Optical Coherence Tomography (OCT) and fundus photography are routinely used in diagnosis, management, and follow up of disorders like diabetic retinopathy, age-related macular degeneration, and glaucoma. We can utilize AI algorithms to analyze these images and provide accurate and precise measurements of various parameters, such as thickness of different layers of retina, macular area, optic disc contours, and cup-to-disc ratio. This can help ophthalmologists not only in the early detection of eye diseases and enable timely interventions but also provide guidelines for prognosis and follow up.