Abd Elaziz Mohamed Elmadina

Bio: Abd Elaziz Mohamed Elmadina is an academic researcher from Qassim University. The author has contributed to research in topics: Noise & Reading (process). The author has an hindex of 1, co-authored 4 publications receiving 3 citations.

The Effect of Phacoemulsification on Corneal Endothelial Cells Morphology and Thickness: Doi:10.36351/pjo.v36i4.1092

Abstract: Purpose: To compare the corneal endothelial cells morphology and central corneal thickness (CCT) before and after phacoemulsification in Sudanese population. Place and Duration of Study: Al-Neelain eye hospital, Khartoum, Sudan, from January 2018 to May 2018. Study Design: Observational longitudinal study. Methods: One hundred and forty eyes of 140 patients with immature senile cataract were selected by convenient sampling. The age ranged from 40 to 85 years. The patients underwent complete ocular examination including morphology of corneal endothelial cells and CCT using computerized non-contact specular microscope. Inclusion criteria for the study was eyes with normal corneal endothelial cells and cell density more than 1000 cells/mm2. We excluded patients with ocular or systemic diseases, previous history of intraocular surgery, refractive surgery or trauma as well as contact lenses wear. The patients underwent phacoemulsification by a single surgeon. The examination parameters were repeated one month after surgery. Descriptive and comparative statistical analyses were performed using SPSS for Windows Version 21.0. Results: There was significant reduction in mean endothelial cells density after phacoemulsification compared to baseline with p < 0.001. There was also significant post-operative reduction in mean endothelial cells number as compared to baseline (P value < 0.001). Mean endothelial cells hexagonality was reduced after surgery with P value of 0.003. No significant difference was found between mean coefficient variation of endothelial cells size before and after phacoemulsification (P = 0.55). Central corneal thickness showed significant increase post-operatively, P = 0.003. Conclusion: Phacoemulsification causes significant damage to corneal endothelium cells, including decrease in corneal endothelial cell density, hexagonality and cell number. Key Words: Corneal endothelium, Endothelial cell density, Central corneal thickness, Phacoemulsification.

Sensitivity and Specificity of Sheard and Percival’s Criteria for the Diagnosis of Young People with Near-heterophoria

Abstract: BACKGROUND: Sheard and Percival assumed that symptoms from latent strabismus can be avoided if the relevant fusional vergence is adequate to support the heterophoria. AIM: The aim of the study was to determine the sensitivity and specificity of Sheard’s and Percival’s criterion for the diagnosis of heterophoria. METHODS: A cross-sectional hospital-based study was performed at Al-Neelain Eye Hospital Khartoum, Sudan from February to October 2019. Heterophoria was measured using Maddox Wing and fusional vergence using a prism bar. Thereafter, Sheard’s and Percival’s criteria were used for the diagnosis of heterophoria. RESULTS: A total of 230 participants (age = 15–30 years; mean age = 19.34 ± 3.325 years) were recruited for this study. The Sheard’s criteria showed a high sensitivity of 87.2% and a low specificity of 8.0% for the diagnosing of exophoria, with positive and negative predictive values of 65.5% and 26%, respectively. The criteria showed a relatively low sensitivity of 77.8% and a specificity of 9.0% in the diagnosis of esophoria, with a positive and negative predictive values of 56% and 20%, respectively. Percival criteria showed high sensitivity 84.2% and low specificity 9.1% in diagnosing esophoria, with a positive and negative predictive value of 61.5% and 25%, respectively. On the other hand, the criteria showed low sensitivity 67.4% and specificity 13.8% in diagnosing exophoria, with positive and negative predictive value 61.9% and 17%, respectively. CONCLUSION: Sheard’s and Percival’s criteria are useful in diagnosing binocular vision problems. Sheard’s criteria are accurate in diagnosing near exophoria and Percival’s criteria are more accurate in diagnosing near esophoria. Therefore, these criteria provide good clues and predictions for the diagnosis of binocular vision problems.

The Effect of Color and Positional Noise on Reading Performance in Human Vision

Abstract: BACKGROUND: Reading can be described as a complex cognitive process of decrypting signs to create meaning. Eventually, it is a way of language achievement, communication, and sharing information and ideas. Changing lighting and color are known to improve visual comfort and the perceptual difficulties that affect reading for those with poor vision. AIM: This study aims to investigate the effect of changing the wavelengths and different levels of positional noise on reading performance for participants with best-corrected distant visual acuity (BCVA) of 6/6 or better. METHODOLOGY: Twenty English speakers with BCVA 6/6 or better were asked to read words presented in a printed format. The stimuli were black print words in a horizontal arrangement on matte white card. They were degraded using positional noise produced by random vertical displacements of the letter position below or above the horizontal line on three levels. RESULTS: Introducing positional noise affected word recognition differently with different wavelengths. The role of short wavelength in enhancing orthographic reading and word recognition is clear – they reduce the effects of positional noise. The error rate and duration time have different effects with different wavelengths, even when positional noise is introduced. CONCLUSION: The reading rate is not affected by changing the wavelength of the light. However, the mean differences in wpm were affected by changing the wavelengths. Also, introducing positional noise affects word recognition differently with different wavelengths.

The The Effect of Colors and Positional Noise on Reading Performance with Non-words-Part 2

Abstract: BACKGROUND: Reading can be described as a complex cognitive process of decrypting signs to create meaning. Eventually, it is a way of language achievement, communication, and sharing of information and ideas. Changing lighting and color are known to improve visual comfort and the perceptual difficulties that affect reading for those with poor vision. AIM: The main objectives of the current study were to investigate the effect of changing the wavelengths and color with different levels of positional noise on reading performance with non-word for subjects with best-corrected distant visual acuity (BCVA) equal or better than 6/6. METHODOLOGY: In a cross-section interventional study, 20 English speakers were asked to read non-words presented in a printed format. The stimuli were black print words in a horizontal arrangement on a matte white card. They were degraded using positional noise produced by random vertical displacements of the letter position below or above the horizontal line on three levels. RESULTS: Introducing positional noise affected real and non-words recognition differently. The detrimental effects of positional noise with non-words on reading rate were not influenced by changes in wavelengths and color. The long-wavelength reading rate resulted in the lowest performance compared with other wavelengths with all levels of noise. CONCLUSION: Reading performance is affected by changes in the levels of positional noise. However, the reading rate is not affected by changes in wavelength and color with non-words. The long-wavelength reading rate resulted in the lowest performance compared with other wavelengths and color with all levels of noise.

Change in Central corneal thickness after Phacoemulsification

Abstract: Purpose: To determine changes in central corneal thickness after phacoemulsification at first post-operative day, one week and one month. Study Design: Descriptive Observational study. Place and Duration of Study: Sindh Institute of Ophthalmology and Visual Sciences, Hyderabad. From June 2018 to March 2019. Material and Methods: Ninety-two patients with ages between 35 and 72 years presenting with senile and pre-senile cataract were selected by non-probability convenience sampling. Patients with previous ocular surgery, ocular trauma, Glaucoma, Uveitis, Contact lens wear and long-term use of ocular medication were excluded. The patients were subdivided into three groups depending on variability in their corneal thickness. Patients with preoperative central corneal thickness (CCT) from 480 to 529µm were placed in group 1 (Thin), group 2 included patients with CCT ranging between 530 and 569µm (Moderate), patients with CCT from 570-640µm were placed in group 3 (Thick). Preoperative CCT was measured before extraction of cataract via phacoemulsification and then repeated on first post-operative day and then on one week and one month. Results: Preoperative mean central corneal thickness increased by 10.2% on first post-operative day. It reduced to 3.1% on seventh post-operative day. It further reduced to 0.7% on 30th post-operative day. Central corneal thickness reduced to mean value of 548.8µm on 30th post-operative day, which was statistically non-significant as compared with preoperative mean value (544.96µm). Conclusion: There was no statistically significant change in CCT one month after phacoemulsification when compared with the pre-operative CCT.

Commentary: Corneal endothelial cell changes in diabetics versus age-group matched nondiabetics after manual small incision cataract surgery (SICS).

Abstract: Manual small incision cataract surgery is an established alternative to phacoemulsification and gives similar results, with lesser inputs and lesser carbon footprint.[1] However, most of the maneuvers in manual small‐incision cataract surgery are in the anterior chamber, closer to the corneal endothelium, unlike phacoemulsification where the action takes place in the capsular bag. Hence, there has been a perception that manual SICS may cause more endothelial cell loss. Nevertheless, this has been disproved by previous studies.[1,2]

Comparison of Measured Fusional Vergence Amplitudes using Prism Bar and Synoptophore in Sudanese Patients with Near Exophoria

Abstract: Assessment of the fusional vergence amplitudes constitutes one of the most important diagnostic tools to obtain information about the ability to maintain binocular vision. Several techniques can be used to assess this function. However, those methods are not interchangeable, and the measurement repeatability has been questioned. This study aimed to compare fusional vergence range measurements using prism bars and synoptophore in Sudanese patients with near exophoria The study was a comparative cross-sectional hospital-based, performed in the binocular vision clinic at the Al-Neelain Eye Hospital. Fusional vergence amplitudes (positive and negative) were measured on 122 patients (67 females and 55 males), and the mean age and standard deviation were 16.79 ± 5.22 years old using prism bar and synoptophore methods. The findings showed that the higher positive fusional vergence was obtained using the synoptophore method (24.7 ± 7.2 Δ base-out), whereas the prism bar method provided the lower finding (22.6± 7.6 Δ base-out). Conversely, the prism bar method revealed a higher measurement for negative fusional vergence (13.9± 3.9 Δ base-in) than the synoptophore method (12.7± 3.7 Δ base-in). Using the t-test, significant differences were found between all measurements with the two techniques, P<0.05. Measurements of positive and negative fusional vergence amplitudes by the two methods showed no relationship between age and fusional vergence, P>0.05. Given the significant difference in the results obtained between the two methods for measuring the positive and negative fusional vergence amplitudes, caution should be taken when making decisions regarding fusional vergence assessment in patients with latent and manifest strabismus.

The Effect of Phaco Chop Cataract Surgery on Corneal Endothelium

Abstract: : Aim : To evaluate the effect of Phaco Chop Cataract Surgery on Corneal Endothelium. Setting : Kasr Al-Ainy, university hospital, in the period between Aug-2021 to Feb-2022. Methods : A prospective study included 30-eyes that underwent cataract surgery using Phaco-chop technique. Endothelial cell loss (ECL) was correlated to effective phaco-time in seconds (EPT), age of the patients, and their gender 3-months postoperatively using specular microscopy. Results : This study was performed on 30 patients (17-cases were males, and 13-cases were females) who underwent phacoemulsification. Their ages ranged from 55 to 80 years, with a mean of 66.5 (± 6.54) years. The mean preoperative cell density (CD) was 2236 cell/mm 2 , that decreased to 1597 cells/mm 2 , 3-months postoperatively. This drop in CD was statistically significant (p<0.001). There was a significant positive correlation (P<0.0001) between ECL and EPT. Also, there was a significant positive correlation (P<0.0001) between EPT and cataract density. However, there was no correlation (P=0.9316) between ECL and age. Also, t here was no correlation between ECL and gender (P = 0.326). There was significant improvement of visual acuity in all cases (P < 0.0001). Conclusion : Phaco Chop is an effective technique for cataract surgery. However, there was a significant effect on corneal endothelium. ECL was related EPT, which in turn was related type of senile cataract.

The The Effect of Colors and Positional Noise on Reading Performance with Non-words-Part 2

Abstract: BACKGROUND: Reading can be described as a complex cognitive process of decrypting signs to create meaning. Eventually, it is a way of language achievement, communication, and sharing of information and ideas. Changing lighting and color are known to improve visual comfort and the perceptual difficulties that affect reading for those with poor vision. AIM: The main objectives of the current study were to investigate the effect of changing the wavelengths and color with different levels of positional noise on reading performance with non-word for subjects with best-corrected distant visual acuity (BCVA) equal or better than 6/6. METHODOLOGY: In a cross-section interventional study, 20 English speakers were asked to read non-words presented in a printed format. The stimuli were black print words in a horizontal arrangement on a matte white card. They were degraded using positional noise produced by random vertical displacements of the letter position below or above the horizontal line on three levels. RESULTS: Introducing positional noise affected real and non-words recognition differently. The detrimental effects of positional noise with non-words on reading rate were not influenced by changes in wavelengths and color. The long-wavelength reading rate resulted in the lowest performance compared with other wavelengths with all levels of noise. CONCLUSION: Reading performance is affected by changes in the levels of positional noise. However, the reading rate is not affected by changes in wavelength and color with non-words. The long-wavelength reading rate resulted in the lowest performance compared with other wavelengths and color with all levels of noise.