The Correlation between Corneal Topographic Indices and Corneal High Order Aberrations in Keratoconus

Amr MOUNIR, Islam Saad El SAMAN, Mohamed ANBAR

Medical hypothesis discovery and innovation in ophthalmology, Vol. 8 No. 1 (2019), 10 March 2019 , Page 1-6

This study was performed to investigate aberrometric changes of Keratoconus (KC) and its correlation with corneal topographic indices. In a cross sectional study, the researchers included 170 eyes of 138 candidates that were seeking corneal refractive surgery in Sohag refractive center, Sohag, Egypt and had been diagnosed as clinical KC. Patients were divided to mild, moderate, and severe KC. All eyes included in this study were subjected to corneal tomographic evaluation. Corneal aberrometry data was collected from the Sirius topography (Sirius, Costruzione Strumenti Oftalmici, Italy) over a 5-mm diameter. The collected data included Zernike coefficients for corneal aberrations, including total Root Mean Square (RMS), RMS Spherical Aberration (SA), RMS Coma, and RMS astigmatism. The study population was divided to mild, moderate, and severe KC. Mild KC cases included 58 eyes of 46 patients, moderate KC were 64 eyes of 52 patients, and severe KC were 48 eyes of 40 patients. Root mean square total was statistically significant in all groups with a higher p value in moderate KC (P = 0.001) and also was statistically significant when compared in the three groups altogether (P = 0.0001). Coma aberration was statistically significant in mild and moderate KC and when compared between the three groups (P = 0.0001). Root mean square Trefoil aberration was statistically significant only in moderate KC yet was statistically significant when compared in all groups (P = 0.0001). Root mean square astigmatism was statistically significant in mild KC only and when compared in the three groups altogether (P = 0.0001). Spherical aberration was also statistically significant in moderate and severe KC with a P value of < 0.0001 and 0.001, respectively. There was a positive correlation between posterior elevation and RMS values in mild and moderate KC while there was negative or very weak positive correlation in severe KC. There were negative correlations between the thinnest location and RMS values in nearly all variables in the three groups except weak positive correlation with RMS astigmatism in mild KC and with RMS total and coma aberration in severe KC .In conclusion corneal high order aberrations measured by the Sirius topography system had low to moderate correlation with corneal topographic indices provided by the same device in different grades of KC.

Spontaneous Pupillary Recovery of Urrets-Zavalia Syndrome Following Descemet’s Membrane Endothelial Keratoplasty

Marco M. S. ISAC, Darren Shu Jeng TING, Trushar PATEL

Medical hypothesis discovery and innovation in ophthalmology, Vol. 8 No. 1 (2019), 10 March 2019 , Page 7-10

To report a case of Urrets-Zavalia syndrome (UZS) with spontaneous pupillary recovery following Descemet's membrane endothelial keratoplasty (DMEK). This was an interventional case report with literature review. A 37-year-old female phakic patient presented to our clinic with bilateral decreased vision secondary to worsening Fuch’s endothelial dystrophy. She underwent bilateral inferior peripheral iridotomies prior to undergoing left DMEK surgery under general anaesthesia. The DMEK surgery was uncomplicated but she had a large fixed and dilated left pupil on the following day despite a normal examination with a normal intraocular pressure. A diagnosis of UZS was made. The pupil remained fixed and dilated until 4 months postoperatively, which anisocoria started to improve by time. At 6 months postoperative, anisocoria had fully resolved with normal pupillary reactions and complete resolution of photopic symptoms. UZS is a rare complication of DMEK surgery and, to our best knowledge, only one case has been reported in the literature. Surgeons and patients should be aware of this potential phenomenon following uneventful DMEK surgery. Conservative measures should be considered for initial management of UZS in young patients as spontaneous recovery may sometimes ensue, as occurred in our case.

Intrafamilial Phenotype Variability in Two Male Siblings, With X-linked Juvenile Retinoschisis and Dorzolamide Treatment Effect in the Natural History of the Disease


Medical hypothesis discovery and innovation in ophthalmology, Vol. 8 No. 1 (2019), 10 March 2019 , Page 11-15

To investigate how genotype is related to phenotype and document correlations of genotype-phenotype with response of topical administration of dorzolamide in siblings affected with X-linked juvenile retinoschisis (XLRS). We performed a retrospective study on two male siblings (four eyes) with XLRS, who were treated with topical installation of dorzolamide. Clinical diagnosis was supported with familial genetic analysis with bi-directional Sanger sequencing of RS1 pathogenic variant. Optical coherence tomography (OCT), fundus fluorescein angiography (FFA), ultrasound scan (U/S) and electroretinogram (ERG) were used in the evaluation. Central macular thickness (CMT) and best corrected visual acuity (BCVA) were recorded monthly for eighteen months. We performed genetic analysis in their family for mutations in the gene that encodes the protein retinoschisin, responsible for retinoschisis (RS1).  It was proved that phenotype variability might be related to the same pathogenic variant. While there was an improvement in BCVA and OCT central macular thickness in the patient with the mild form of disease, the visual acuity and the OCT scans of the patient with severe form of disease did not improve. Intrafamilial phenotypic variability between individuals sharing identical pathogenic variant was documented. Both our patients had a pathogenic variant in a hemizygous state at a genomic location in exon 6 of the RS1 gene; Frameshift mutation that is likely to cause protein truncation was identified which is suggested to result in greater clinical severity. Consequently, it was found that response to dorzolamide is correlated to phenotypic severity.

Microbiological Profile of Corneal Ulcers at a Tertiary Referral Center

Mohammad ZARE, Peyman Mohammadi TORBATI, Fahimeh ASADI-AMOLI, Mohammadreza TALEBNEJAD, Maryam PARVIZI, Zahra NASIRI, Reza GHAREBAGHI, Fatemeh HEIDARY

Medical hypothesis discovery and innovation in ophthalmology, Vol. 8 No. 1 (2019), 10 March 2019 , Page 16-21

The aim of this study was to describe patient demographics, microbiological profile, and antibiotic susceptibility of corneal ulcer at a tertiary referral center to improve and optimize diagnosis and treatment of this potentially blinding entity and to reduce antibiotic misuse. Detailed external and slit-lamp bio-microscopic examination of 123 consecutive patients with suspected corneal ulcer was performed at an ophthalmology clinic. Corneal scraping was carried out under slit-lamp bio-microscopy. The obtained material was inoculated on culture media and smeared on a slide for Gram's staining for morphological identification of bacteria and fungus. For samples that developed colony in culture media, antibiotic susceptibility testing was performed. In a significant percentage of patients (72%) neither bacterial agents nor fungi were the cause of corneal ulcer. Of the 34 culture-proven corneal ulcers, in 79% of the cases, bacteria were detected while in 21% of cases, fungi were found. Of the 27 bacterial corneal ulcers, the majority were (67%) caused by Gram-positive bacteria, of which 50% were Streptococcus pneumoniae, and in the Gram-negative bacterial corneal ulcers, most of the cases (44%) were caused by Pseudomonas aeruginosa. In the antibiotic susceptibility report, Streptococcus pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli were resistant to Cotrimoxazole (TS), Streptococcus pneumoniae to Erythromycin (E), Staphylococcus aureus to Peniciline (PG), Pseudomonas aeruginosa to Ceftriaxone (CRO) and Nitrofurantoin (NI), and finally, Escherichia coli to Gentamicin (GM). In conclusion, in a significant number of the patients neither bacterial agents nor fungi were offending microorganisms and bacteria were the most common agent of microbiological corneal ulcer, found in 79% of culture-proven corneal ulcers, followed by fungus, found in 21% of culture-proven corneal ulcers.

The Relationship of Neutrophil to Lymphocyte Ratio with Vitreomacular Traction Syndrome

Cagri ILHAN, Mehmet CITIRIK, Mehmet Murat UZEL, Kemal TEKIN

Medical hypothesis discovery and innovation in ophthalmology, Vol. 8 No. 1 (2019), 10 March 2019 , Page 22-27

This study was conducted to reveal the role of systemic low-grade inflammation by calculating the Neutrophil/Lymphocyte Ratio (NLR) in Vitreomacular Traction Syndrome (VMTS) of different etiologies. A retrospective examination was made of the medical records at a tertiary referral hospital. The study included 31 patients with diabetic VMTS, 27 patients with idiopathic VMTS, and 35 healthy subjects as the control group. The White Blood Cell (WBC) counts and Neutrophil-to-Lymphocyte Ratio (NLR) was compared. There were  insignificant differences between the groups in terms of mean age and female/male ratio (P>0.05). The mean ± Standard Deviation (SD) of NLR was calculated as 2.43 ± 0.83 in the diabetic VMTS group, 2.38 ± 0.96 in the idiopathic VMTS group, and 1.83 ± 0.52 in the control group (P=0.007). The values of the diabetic and idiopathic VMTS groups were significantly higher than those of the control group (P=0.002 and P=0.032, respectively). However, differences between the diabetic and idiopathic VMTS groups were insignificant (P=0.651). This study found significantly higher NLR in patients with diabetic and idiopathic VMTS than the control group. Elevated NLR could therefore be a potential indicator of VMTS, irrespective of the etiology.

Association of the Myocilin Gene Polymorphism With Primary Open Angle Glaucoma


Medical hypothesis discovery and innovation in ophthalmology, Vol. 8 No. 1 (2019), 10 March 2019 , Page 28-33

Glaucoma is the second cause of irreversible blindness, and the Primary Open Angle Glaucoma (POAG) subtype is the most common type of glaucoma. It has been shown that genetic mutations increase the risk of POAG used for early detection. The aim of the current study was to determine the association between genetic variations of Myocilin (MYOC) gene and susceptibility to POAG in the Iranian population. This case-control study was conducted on patients with POAG, referred to Khatam-al Anbia Eye Hospital, Mashhad, Iran. The control group was selected from healthy patients with a refractive disorder, who had referred to this hospital. After extracting the DNA from the whole blood sample, the Polymerase Chain Reaction-Single-Strand Conformation Polymorphisms (PCR-SSCP) method was used to discriminate variability in sequences in three exons of MYOC gene locus, known as GLC1A. Clinical characteristics of the subjects, comprised of visual acuity, Cup to Disc Ratio (CDR), and Intra-Ocular Pressure (IOP) were statistically compared between the wild and mutant type of the MYOC gene using independent samples t-test, Chi-square, and logistic regression test with SPSS version 15.0 software. P-values of < 0.05 were considered significant. One hundred and forty participants (75.1% males) were studied in two groups of case (n = 70) and control (n = 70). The frequency of mutant alleles in patients and healthy groups was statistically significant (40% versus 11.5%, Odd’s Ratio (OR): 5.1, CI 95% for OR: 2.1 to 12.4, P-value < 0.001). Also, the detected mutation in the case group was significantly higher in exon 1 and 3 (15.7% versus 0%, P-value = 0.001, and 11.5% versus 2.8%, P-value = 0.049, respectively). Based on the result of the current study, it seems that the MYOC gene polymorphisms increased the risk of POAG in the Iranian population.

Repeatability, Reproducibility and Agreement of Central Corneal Thickness Measurements by Two Noncontact Pachymetry Devices


Medical hypothesis discovery and innovation in ophthalmology, Vol. 8 No. 1 (2019), 10 March 2019 , Page 34-39

This study was designed to assess the repeatability, reproducibility, and agreement of Noncontact Pachymetry (NPC) (Topcan TRK-2P) and the non-contact optical low coherence reflectometer (Lenstar LS 900) devices for measuring Central Corneal Thickness (CCT) of healthy corneas. A total of 82 healthy volunteers were evaluated. The first observer used both the TopconTRK-2P and Lenstar 900 devices while the second observer only used the TopconTRK-2P for the measurements. The measurements with either device were repeated three times for each patient, consecutively. The central corneal thickness measurements with the Topcon TRK-2P revealed mean ± Standard Deviation (SD) values of 553.1 ± 36.1 micrometer (µm) for the first observer and 552.3 ± 35.9µm for the second observer and the mean ± SD of CCT was 537.3 ± 34.8µm with the Lenstar 900. The difference between the CCT measurements of the observers using the Topcon TRK-2P (P = 0.142) was insignificant. However, significantly lower measurements were found with the Lenstar 900 compared with the Topcon TRK-2P (P ˂ 0.001). The central corneal thickness measurements obtained by the Topcon TRK-2P were found to have high repeatability for both observers with a lower SD, less than 1% Coefficient of Variation (CV) and higher than 0.99 Intra-Class Correlation Coefficient (ICC) (Observer 1: 3.77 SD, 0.68 CV and 0.995 ICC; the second observer: 3.58 SD, 0.65 CV and 0.995 ICC). There was an excellent inter-observer reproducibility between the two observers for Topcon TRK-2P with 2.71 SD, 0.49 CV, and 0.994 ICC. The Bland-Altman plot showed high agreement between the two devices. These results suggest that the TopconTRK-2P is a reliable device for evaluating CCT in healthy corneas compared with Lenstar 900.

Expression and Localization of Glycosaminoglycans/Proteoglycan in Pterygium: An Immunohistochemical Study

Constantinos D. GEORGAKOPOULOS, Olga E. MAKRI, Dionisios PAGOULATOS, Nikolaos K. KARAMANOS

Medical hypothesis discovery and innovation in ophthalmology, Vol. 8 No. 1 (2019), 10 March 2019 , Page 40-43

Pterygium is a triangle-shaped fibrovascular hyperplasia of the bulbar conjunctiva on the cornea. The purpose of this study was to analyze Proteoglycans (PGs) by Immunohistochemistry (IHC) in pterygium tissues and to compare the results with normal conjunctiva. Twenty-four patients (14 males) undergoing primary pterygium excision and 17 healthy individuals (10 males), undergoing extracapsular cataract surgery, were included. Pterygium tissues and normal conjunctiva tissues were surgically removed. The tissue sections were fixed in 2% paraformaldehyde and incubated with monoclonal antibodies against PGs anti-mouse IgG. Immunohistochemical study showed stronger expression of keratan sulfate in the stroma of the pterygium compared to normal conjunctiva. An increased expression of heparan sulfate was observed in the epithelial layer and around the pterygium vessels. On the other hand, dermatan sulfate showed an increased expression and localization not only in the sub-epithelial area of the pterygium and normal conjunctiva, yet throughout the stroma of the pterygium. The differences in the expression and localization of the studied extracellular matrix proteoglycans in the pterygium tissue compared to normal conjunctiva may explain the tissue hyperplasia, structure, and the functional properties in pterygium.

The Effect of Glaucoma Medication on Choroidal Thickness Measured with Enhanced Depth-Imaging Optical Coherence Tomography

Serife BAYRAKTAR, Zafer CEBECI, Belgin IZGI, Kamber KASALI

Medical hypothesis discovery and innovation in ophthalmology, Vol. 8 No. 1 (2019), 10 March 2019 , Page 44-51

The aim of this study was to examine the effect of the glaucoma medication on Choroidal Thickness (CT) in those with Primary Open-Angle Glaucoma (POAG) and normal cases. This prospective study included 27 patients with newly diagnosed POAG (group 1; 49 eyes), undergoing glaucoma treatment, and 30 patients, whose treatment was terminated due to misdiagnosis (group 2; 57 eyes). Choroidal thickness was measured using Enhanced Depth Imaging (EDI) with Spectral Domain Optical Coherence Tomography (SD-OCT) at the first visit and almost one month later. In group 1, the mean Sub-Foveal CT (SFCT) was 301 ± 91 µm, the mean CT was 264 ± 87 µm at the nasal point, 1 mm to the fovea, and 271 ± 84 µm at the temporal point, 1 mm to the fovea. The second measurements were obtained as 39 ± 8.5 days after treatment began; the SFCT was 319 ± 85 µm (P = 0.0017), the nasal 1 mm CT was 275 ± 88 µm (P = 0.162), and the temporal 1mm CT was 291 ± 80 µm (P = 0.007). In group 2, the mean SFCT was 292 ± 100 µm, the nasal 1 mm CT was 254 ± 97 µm, and the temporal 1 mm CT was 261 ± 97 µm. The second measurements were obtained 37.5 ± 5.5 days after the treatment ended; the SFCT was 295 ± 107 µm (P = 0.212), the nasal 1 mm CT was 262 ± 104 µm (P = 0.709), and the temporal 1 mm CT was 266 ± 104 µm (P = 0.792). Glaucoma medication affects the CT as a marker for choroidal blood flow in patients with glaucoma. Further studies with larger sample sizes are required to examine each glaucoma medication subgroup.

Ocular Surface Evaluation After the Substitution of Benzalkonium Chloride Preserved Prostaglandin Eye Drops by a Preservative-free Prostaglandin Analogue

Nara Lidia Vieira LOPES, Carolina P. B. GRACITELLI, Maria Regina CHALITA, Nubia Vanessa dos Anjos Lima Henrique DE FARIA

Medical hypothesis discovery and innovation in ophthalmology, Vol. 8 No. 1 (2019), 10 March 2019 , Page 52-56

To evaluate ocular surface changes after withdrawal of Benzalkonium chloride (BAK) in patients with glaucoma in monotherapy with BAK-preserved prostaglandin. This was a prospective observational study. All patients underwent complete ophthalmologic examination and evaluation of ocular surface. A questionnaire was filled regarding symptoms of dry eye (Ocular Surface Disease Index [OSDI]) at the beginning of study. The treatment was switched to preservative-free tafluprost for 6 weeks and after this period, all patients were re-evaluated. All patients reported improvement of symptoms. The green lissamine test showed a significant improvement of the ocular surface, with most patients classified as light dry eye (P < 0.001). A significant improvement in the score (P < 0.001) was also found, with an average of 17.95 ± 5.35 points, which classifies the patients' symptoms in the normal to light zone. Benzalkonium chloride withdrawal reduced the signs and symptoms of dry eye in patients with primary open angle glaucoma (POAG).