bluuebunny/crossref_metadata_2025 huggingface dataset:
The Mathematical Safe Problem and Its Solution (Part 1)
Authors: Kryvyi S. , Hoherchak H.
Published: January 2021

Introduction. The problem of the mathematical safe arises in the theory of computer games and cryptographic applications. The article considers the formulation of the mathematical safe problem and the approach to its solution using systems of linear equations in finite rings and fields.

The purpose of the article is to formulate a mathematical model of the mathematical safe problem and its reduction to systems of linear equations in different domains; to consider solving the corresponding systems in finite rings and fields; to consider the principles of constructing extensions of residue fields and solving systems in the relevant areas.

Results. The formulation of the mathematical safe problem is given and the way of its reduction to systems of linear equations is considered. Methods and algorithms for solving this type of systems are considered, where exist methods and algorithms for constructing the basis of a set of solutions of linear equations and derivative methods and algorithms for constructing the basis of a set of solutions of systems of linear equations for residue fields, ghost rings, finite rings and finite fields. Examples are given to illustrate their work. The principles of construction of extensions of residue fields by the module of an irreducible polynomial, and examples of operations tables for them are considered. The peculiarities of solving systems of linear equations in such fields are considered separately. All the above algorithms are accompanied by proofs and estimates of their time complexity.

Conclusions. The considered methods and algorithms for solving linear equations and systems of linear equations in finite rings and fields allow to solve the problem of a mathematical safe in many variations of its formulation. The second part of the paper will consider the application of these methods and algorithms to solve the problem of mathematical safe in its various variations.

Keywords: mathematical safe, finite rings, finite fields, method, algorithm, solution.
Optimized Layout of Spherical Objects in a Polyhedral Domain
Authors: Romanova T. , Yaskov G. , Chugay A. , Stoian Y.
Published: January 2021

Introduction. The article studies the problem of arranging spherical objects in a bounded polyhedral domain in order to maximize the packing factor. The spherical objects have variable placement parameters and variable radii within the given upper and lower bounds. The constraints on the allowable distance between each pair of spherical objects are taken into account.

The phi-function technique is used for analytical description of the placement constraints, involving object non-overlapping and containment conditions.

The problem is considered as a nonlinear programming problem. The feasible region is described by a system of inequalities with differentiable functions.

To find the local maximum of the problem the decomposition algorithm is used. We employ the strategy of active set of inequalities for reducing the computational complexity of the algorithm. IPOPT solver for solving nonlinear programming subproblems is used.

The multistart strategy allows selecting the best local maximum point.

Numerical results and the appropriate graphic illustration are given.

The purpose of the article is presenting a mathematical model and developing a solution algorithm for arranging spherical objects in a polyhedral region with the maximum packing factor. It allows obtaining a locally optimal solution in a reasonable time.

Results. A new formulation of the problem of arranging spherical objects in a polyhedral domain is considered, where both the placement parameters and the radii of the spherical objects are variable. A mathematical model in the form of nonlinear programming problem is derived. A solution approach based on the decomposition algorithm and multistart strategy is developed. The numerical results combined with the graphical illustration are given.

Conclusions. The proposed approach allows modeling optimized layouts of spherical objects into a polyhedral domain.

Keywords: layout, spherical objects, polyhedral domain, phi-function.
Optimal Numerical Integration
Authors: Zadiraka V.K. , Luts L.V. , Shvidchenko I.V.
Published: January 2021

Introduction. In many applied problems, such as statistical data processing, digital filtering, computed tomography, pattern recognition, and many others, there is a need for numerical integration, moreover, with a given (often quite high) accuracy. Classical quadrature formulas cannot always provide the required accuracy, since, as a rule, they do not take into account the oscillation of the integrand. In this regard, the development of methods for constructing optimal in accuracy (and close to them) quadrature formulas for the integration of rapidly oscillating functions is rather important and topical problem of computational mathematics. The purpose of the article is to use the example of constructing optimal in accuracy (and close to them) quadrature formulas for calculating integrals for integrands of various degrees of smoothness and for oscillating factors of different types and constructing a priori estimates of their total error, as well as applying to them of the theory of testing the quality of algorithms-programs to create a theory of optimal numerical integration. Results. The optimal in accuracy (and close to them) quadrature formulas for calculating the Fourier transform, wavelet transforms, and Bessel transform were constructed both in the classical formulation of the problem and for interpolation classes of functions corresponding to the case when the information operator about the integrand is given by a fixed table of its values. The paper considers a passive pure minimax strategy for solving the problem. Within the framework of this strategy, we used the method of “caps” by N. S. Bakhvalov and the method of boundary functions developed at the V.M. Glushkov Institute of Cybernetics of the NAS of Ukraine. Great attention is paid to the quality of the error estimates and the methods to obtain them. The article describes some aspects of the theory of algorithms-programs testing and presents the results of testing the constructed quadrature formulas for calculating integrals of rapidly oscillating functions and estimates of their characteristics. The problem of determining the ranges of admissible values of control parameters of programs for calculating integrals with the required accuracy, as well as their best values for integration with the minimum possible error, is considered for programs calculating a priori estimates of characteristics. Conclusions. The results obtained make it possible to create a theory of optimal integration, which makes it possible to reasonably choose and efficiently use computational resources to find the value of the integral with a given accuracy or with the minimum possible error. Keywords: quadrature formula, optimal algorithm, interpolation class, rapidly oscillating function, quality testing.
Frequency of Retinoblastoma at Lady Reading Hospital, Peshawar, Pakistan
Authors: Iqbal Zafar , Saeed Tariq Muhammad
Published: January 2021

Aim: To ascertain the demographics, clinical features, and treatment options for children with retinoblastoma. Methods: This was a hospital-based cohort study of all children with retinoblastoma presenting from 1 January 2008 to 31 December 2008. Demographic data, presenting features, family history, and findings identified during examination were recorded for each patient. The tumours were classified using the Reese- Ellsworth classification system. Documentation of the tumours included examination under anesthesia, ultrasound B- scan, and computed tomography scan as well as histopathological reporting of enucleated eyes.Results: Twenty seven new patients with retinoblastoma were identified and 36 eyes were affected, with a bilaterality rate of 33%. The frequency was 4.1, with a bimodal peak of presentation of younger than 1 yearand 4 years. The mean age at diagnosis was 3.2 years (SD, 2.5 years; range, 3 months to 8 years). Most of the patients were boys, (59%) and most were in the age range of 1 to 5 years (66%). There was a male preponderance (5:1) amongst patients younger than 1 year and the male to female ratio was equal (1:1) in the 1 to 5 years age range. Leukocoria was the main presentation in 38% of eyes and 19% presented with proptosis. Enucleation/exenteration was performed for 17 unilateral eyes (94%) and 5 bilateral eyes (27%) with group V disease. Groups I and II tumours (n = 1 and n = 7 for unilateral and bilateral eyes, respectively) were treated conservatively with cryotherapy or chemotherapy alone or in combination. The commonest treatment for bilateral disease was enucleation of 1 eye and chemotherapy for the fellow eye (22%). Radiotherapy was advised for patients with histopathological evidence of optic nerve involvement (25%).Conclusions: Retinoblastoma usually affects infants and children younger than 5 years, with no sexual or racial predilection. One-third of patients demonstrate bilaterality, with leukocoria as the commonest presenting feature and proptosis as a feature of late presentation. In bilateral retinoblastoma, primary enucleation of one eye with conservative chemotherapy and/or cryotherapy of the fellow eye is advocated.
Effect of Desonide 0.25% Ophthalmic Solution on Central Corneal Thickness and Intraocular Pressure of Patients with Allergic Conjunctivitis
Authors: Sahin Ozlem Gurses
Published: January 2021

Aim: To evaluate whether a significant difference exists between the initial and final mean central corneal thickness that might affect Goldmann applanation tonometer recordings of patients with allergic conjunctivitis treated with desonide 0.25% ophthalmic solution, and to determine the effect of desonide on intraocular pressure by using adjusted intraocular pressure values.Methods: This double-blind randomised placebo-controlled trial enrolled 30 patients (60 eyes) with allergic conjunctivitis. Patients were randomly assigned to receive desonide to 1 eye (study eye) and preservative-free tear supplement (Tears Naturale Free®) to the other eye (control eye) 3 times daily for 3 weeks. Goldmann applanation tonometry and central corneal thickness of both eyes were recorded on the day of presentation and 3 weeks later.Results: Regression of itching, tearing, conjunctival hyperaemia, and tarsal conjunctival papillary reaction were noted in the study eyes after 3 weeks of treatment. The control eyes showed mild regression of pruritis, tearing, conjunctival hyperaemia, and tarsal conjunctival papillary reaction after 3 weeks. There was a significant difference between the initial and final mean central corneal thickness values for the study eyes (p = 0.003). There were no statistically significant differences between the initial and final mean values of Goldmann applanation tonometry and adjusted intraocular pressure for the study eyes. No statistically significant differences were found between the initial and final mean values of any of the parameters for the control eyes.Conclusion: Inflammation-induced increase in central corneal thickness of patients with allergic conjunctivitis treated with desonide showed statistically significant regression. However, this regression did not significantly affect Goldmann applanation tonometry and adjusted intraocular pressure values of the treated eyes.
Detection of Senile Scleral Plaque after Head Trauma
Authors: Guigui Sarah , Lifshitz Tova , Baidousi Amjad , Yagev Ronit , Levy Jaime
Published: January 2021

Senile scleral plaques are late onset ocular calcifications, and are usually detected incidentally on orbital computed tomography scan following trauma. This report is of 4 elderly patients with senile scleral plaques who were admitted to the emergency room following trauma to the head. A head/orbital computed tomography scan was performed as part of the routine examination. In all 4 patients, computed tomography scan revealed a clear retina and no scleral perforation or foreign body intrusion, but bilateral radiodense areas were located anterior to the insertion of the horizontal rectus muscles. These areas were diagnosed as senile scleral plaques. Even though these ocular calcifications are benign, they have important prognostic implications, and should therefore be identified correctly and not confused with other ocular pathologies.
Effect of phacoemulsification with intraocular lens implantation in eyes with cataract and functioning filtering blebs
Authors: Maheshwari Devendra , Ramakrishanan Rengappa , Kader Mohideen Abdul , Pawar Neelam , Gupta Ankit
Published: January 2021

Aim: To evaluate the effect of phacoemulsification with intraocular lens implantation in eyes with pre-existing trabeculectomy.Methods: This prospective single-center clinical study evaluated intraocular pressure in 60 eyes of 60 patients who underwent phacoemulsification and implantation of a foldable intraocular lens after a previous successful trabeculectomy. Patients who had a trabeculectomy more than one year prior to the study were included. Intraocular pressure, number of antiglaucoma medications, bleb appearance, and visual acuity were recorded preoperatively, and at each follow-up examination and 12 months after phacoemulsification.Results: The mean intraocular pressure before phacoemulsification was 12.42 mmHg (SD, 4.60 mmHg), which increased to 14.98 mmHg (SD, 4.18 mmHg), 14.47 mmHg (SD, 3.58 mmHg), 15.44 mmHg (SD, 3.60 mmHg), and 15.71 mmHg (SD, 3.47 mmHg) after one, three, six, and 12 months, respectively. At each follow-up visit, the mean IOP was significantly higher than the preoperative value (p < 0.001, p = 0.015, p ≤ 0.001, and p = 0.001 at month one, three, six, and 12, respectively). The mean preoperative best-corrected visual acuity was 0.98 logMAR (SD, 0.44 logMAR) and the mean postoperative best-corrected visual acuity at 12 months was 0.20 logMAR (SD, 0.21 logMAR) [p = 0.0001]. The mean preoperative number of antiglaucoma medications used was 0.57 (SD, 0.63), which increased to 0.65 (SD, 0.63 ), 0.70 (SD, 0.72 ) 0.68, (SD, 0.70), and 0.67 (SD, 0.77 ) at one, three, six, and 12 months, respectively, but there were no statistically significant differences. Bleb size decreased clinically after phacoemulsification. Nineteen of 60 eyes (32%) developed fibrosis of bleb with decreased bleb size.Conclusion: Phacoemulsification with intraocular lens implantation significantly increased intraocular pressure and increased the number of antiglaucoma medications in eyes with pre-existing functioning filtering blebs.
Anterior lamellar recession in the management of the trachomatous cicatricial entropion of the upper eyelids: Outcomes and indications
Authors: Owji Naser , Tehrani Jamshidian
Published: January 2021

Aim: To evaluate the success and complications of anterior lamellar recession (ALR) in trachomatous cicatricial entropion.Methods: Twenty-six consecutive patients (forty upper eyelids) with trachomatous cicatricial entropion underwent ALR between 2003 and 2010. All patients had aberrant lashes with severe abnormal lid margin. Anatomical success was defined as disappearance of lid margin abnormality. Presence of aberrant lash did not indicate a treatment failure. Complete success was described as anatomical success without abrading abnormal lashes.Results: ALR was performed on the 40 upper eyelids (19 right and 21 left). The average duration of follow-up time was 34 months (range: six to 84 months). Anatomical success was achieved in 28 out of 40 lids (70%). Trichiasis developed in 18 eyelids post-operatively (45%), so complete success rate was 55%.Conclusion: ALR is a well-established procedure with an acceptable success rate for management of trachomatous cicatricial entropion and severe lid margin abnormality. The most important drawback of this procedure is development of trichiasis.
SLT may compromise the corneal endothelium
Authors: Ong Keith
Published: January 2021

Purpose: Whitish spots are sometimes noted in the corneal endothelium after Selective Laser Trabeculoplasty (SLT). One wonders whether this could be laser burns to the corneal endothelium. To evaluate the corneal endothelium after SLT, corneal specular microscopy was performed before and after SLT.Method: 20 patients with open angle glaucoma, who had SLT in February-March 2012, had their corneal endothelium examined with specular microscopy before and after SLT.Results: 4 of the 20 patients showed numerous dark patches/spots on specular microscopy photographs of corneal endothelium after SLT. These dark patches/spots were found to have resolved by one month. 6 of the 20 patients showed few dark patches/spots after SLT. 10 patients had no significant dark patches/spots after SLT.Conclusion: The effect of SLT on the corneal endothelium is probably transient, and longterm effects probably negligible in normal corneas. However, in compromised corneas and corneas with pigment deposits on endothelium or reduced corneal endothelial transparency, there may be a risk of corneal endothelial compromise especially following repeated SLT. The results of this study highlight caution when deciding to do repeat SLT.
Frontalis muscle flap as sling in severe ptosis
Authors: Nagpal Ramesh C. , Grover Ashima , Maitreya Amit , Baradur Harsh
Published: January 2021

Aim: Evaluation of the effect of frontalis muscle flap as sling surgery in severe ptosis with poor levator palpebral superioris (LPS) action.Method: Twenty-five eyes of 18 patients with severe congenital ptosis with poor LPS action were studied over a period of two years. It comprised of 13 eyes of 13 patients of severe unilateral congenital ptosis and ten eyes of five patients with ptosis associated with blepharophimosis syndrome. All patients underwent frontalis muscle flap sling surgery and were followed for six months.Result: At final follow up, 88% of patients had a satisfactory result. No patients required re-surgery. Lagophthalmos was the most common complication seen which subsided by six months. The surgical lid elevation was effective without any recurrence or complete failure.Conclusion: Frontalis muscle flap sling surgery is an effective procedure for severe ptosis with poor LPS action.
Unilateral neonatal glaucoma (buphthalmos) with persistent hyperplastic primary vitreous
Authors: Bhasker Shashi Kumar , Jain Astha , Srivastava P K
Published: January 2021

Leukocoria or white pupillary reflex in infancy or childhood is mostly associated with retinoblastoma (an intraocular malignancy). The possibility is increased if buphthalmos is also present, because non-malignant conditions like persistent hyperplastic primary vitreous (PHPV) usually have normal or small eyes. They rarely present with enlarged buphthalmic eye. Such was the condition in our neonate who presented with buphthalmos and leukocoria and was referred to us for management having been diagnosed with retinoblastoma. However, on investigating by imaging techniques (ultrasonography, Doppler and CT Scan) PHPV was confirmed, which is non-malignant. The patient was managed accordingly without enucleation. Even though rare, neonates or infants presenting with buphthalmos and leukocoria, should be investigated for non-malignant conditions like PHPV by imaging techniques to rule out a malignant condition – retinoblastoma.
A family with Von Hippel-Lindau disease with different presentations
Authors: Wong Ching-lin , Lee Ming-Yueh , Sunder R. , Jamalia R. , Karunakar T.V.N. , Joseph A.
Published: January 2021

Objective: To report three cases of Von Hippel-Lindau (VHL) disease from a family with different presentations.Method: Case series.Results: Case 1, a 14-year-old Malay boy with a history of gradual blurring of vision in both eyes presented with sudden deterioration of right vision. Fundus examination revealed bilateral retinal capillary hemangioma with exudative retinal detachment. His right eye underwent combination therapy of laser photocoagulation, cryotherapy, intravitreal anti-VEGF and photodynamic therapy, but failed to improve vision. His left visiondeteriorated and eventually required surgical intervention. Case 2 was the sister of case 1. She was a 17-year-old Malay girl who presented with sudden onset of left eye pain and redness. Diagnosis of left eye rubeotic glaucoma with closed funnel retinal detachment secondary to a huge retinal hemangioma was made. She underwent left eye external drainage of subretinal fluid plus anterior retinal cryopexy. The rubeotic vessel regressed postoperatively and IOP reduced. Case 3 was the eldest sister of case 1; a 19-year-old Malay girl who came for eye screening after two of her siblings were diagnosed with VHL. She was, however, asymptomatic. Fundus examination revealed right retinal capillary hemangioma. She was treated with laser photocoagulation and her condition remained stable. Systemic investigations identified midline cystic masses in the brain, spine and pancreas. Conclusions: This case series highlight different clinical pictures of Von Hippel-Lindau disease. As marked visual loss is a dreadful sequela of VHL, it is important to screen the family members as early detection and management of ocular and systemic lesions save sight and life.
Keratoconus associated with cone-rod dystrophy
Authors: Kannan Balaji
Published: January 2021

Keratoconus is known to be associated with a variety of ocular and systemic disorders. The common posterior segment disorders known to be associated with keratoconus are retinitis pigmentosa, macular coloboma, Leber’s congenital amaurosis, retinal aplasia and retrolental fibroplasias. Occurrences of keratoconus in association with tapetoretinal degeneration is rare and has been reported infrequently. Visualization of the fundus is often difficult in cases of keratoconus due to the associated refractive error and corneal opacities. This may make it difficult for the ophthalmologist to clinically diagnose associated macular degenerative changes preoperatively. We report a case of keratoconus who was diagnosed to have cone-rod dystrophy following successful corneal transplantation.
Retained orbito-sinal wooden foreign body as an unsuspected cause of	epistaxis: A case report
Authors: WADHWA VIKRAM , Tandon Swati , CHITGUPPI CHANDALA , Sura Jaffer Husein , Rajan Samuel , Chauhan Anju
Published: January 2021

We describe an unusual case of a orbito-sinal wooden stick lodged in ethmoid sinus in a 42 year old male with epistaxis which was undetected for 3 months. The foreign body (FB) was removed successfully by endoscopic approach without complications.
Soft prosthetic contact lens practice in Indian scenario
Authors: Das Biman , MAHADEVAN RAJESWARI
Published: January 2021

Aim: The aim of this study is to investigate the prescribing trend of prosthetic soft contact lens (PSCL) in a tertiary eye care center inIndia.Design: RetrospectiveMethods: The electronic medical records of 223 patients who were prescribed PSCL for various indications for a period of 1 year in a tertiary eye care center were investigated. Parameters investigated were age, gender, indication for PSCL, prescribed base curve, diameter, type and iris tint of PSCL, number of trials required to achieve desirable cosmesis or fit, duration of use of PSCL and number of PSCLs dispensed from off the shelf.Result: A total 223 patients were prescribed PSCL for a period of 1 year, of which 221 patients were prescribed PSCL for one eye and only 2 patients for both the eyes. The mean age of the patients was 29.15 years (SD ± 12.65). Majority of the patients were male (64.57%). Type D PSCL was prescribed for 183 eyes (81.33%), type C PSCL for 38 eyes (16.88%) and type A PSCL for only 4 eyes (1.77%).Among type D PSCL users 81.96% eyes were fitted with various shades of brown colour iris tint. The main categories for prescribing type D soft PSCLs were corneal opacity (34.42%; 63 eyes), band shaped keratopathy (19.67%; 36 eyes) and vascularized corneal opacity (13.11%; 24 eyes). The most common base curves prescribed among type D PSCL users were 8.6 and 8.7 mm and most common diameters prescribed were 13.8 and 14 mm.The major categories for prescribing type C PSCLs were corneal abnormalities (55.26%; 21 eyes) and pupil or iris abnormalities (34.21%; 13 eyes).Only four patients (four eyes) were prescribed with type A PSCL and the only reason was leukocoria due to cataract.Conclusions: PSCL can be a better option for cosmesis in patients with disfigured eyes who do not want complicated surgeries or procedures like enucleation with prosthesis shell implantation or corneal tattooing. Customization is also necessary for PSCL for better fitting and iris colour matching as per the fellow (unaffected) eye.
Usefulness of the Non-Contact Tonometry in Out-Patient Screening
Authors: Selvin Satheesh Solomon T , Jacob Chris Elsa Samson , Kuriakose Thomas
Published: January 2021

Purpose: Goldmann applanation tonometry (GAT) is considered the gold standard for Intraocular Pressure (IOP) measurement. It has the disadvantages of being a contact device, need for a slit-lamp, non-portability and need of a skilled examiner. Many hospitals are using a Non Contact Tonometry (NCT) as a screening device to save clinician time, however the usefulness is not proved in terms of reliability. This study was aimed to determine the usefulness of the Air-puff tonometer (TONOREF NIDEK II, NIDEK CO., LTD., JAPAN) over a GAT in a tertiary care center. Design: Cross-sectional Study Methods: This was a cross-sectional, non interventional observational study conducted on 224 eyes (right eye) from 224 patients. All patients underwent the IOP measurement with both methods and a central corneal thickness (CCT) measured. The data was analyzed using SPSS 20.0 software. Results: The mean age of the patients was 40.3±11.29 years. There was a statistically significant difference (p<0.001) between the mean NCT and GAT readings which persisted even after correction for central corneal thickness. The correlation between NCT and GAT using Pearson’s correlation coefficient was strong irrespective of the corrections for their corneal thickness (r = 0.751 and 0.718 for uncorrected and corrected values respectively). The correlation of the individual clinicians for the readings varied from moderate to strong. The ROC curve showed the best sensitivity and specificity to occur at around 13 to 14 mmHg. Conclusion: NCT seems to overestimate the IOP at low ranges as compared to the GAT and underestimate at higher ranges. The crossover of the values is seen between 12 to 13 mmHg.  The clinician should do an individualized analysis of his/her GAT measurements to the readings of the NCT machine at the clinic to obtain clinician specific nomogram.
The results of therapeutic keratoplasties performed in severely thinned or perforated corneas
Authors: Yuksel Bora , Binzet Menekse , Uzunel Umut Duygu , Kusbeci Tuncay
Published: January 2021

Purpose: To report the visual and anatomic outcomes of therapeutic keratoplasties performed in severely thinned or perforated corneas.Material and methods: Medical records of 37eyes of 37 patients operated between 2000 to 2014 were reviewed retrospectively. Indications, preoperative findings, surgical procedures, donor size, post-operative graft clarity, visual improvement, globe integrity and follow-up periods were analyzed. Mean age was 57,7 (20-85 ). Nineteen patients were male and 18 female. Mean follow-up was 28.7 (14-132) months.Results: Surgical indication was infectious in 17 (45.9%) and noninfectious in 20 eyes (54.1%). Infectious causes were bacterial ulcer 8 (21.7%), herpes simplex 7 (18.9%) and fungus in 2 (5.4%) eyes. Noninfectious causes were traumatic 6 (16.2%), Stevens-Johnson syndrome 2 (5.4%), desmatocele 2 (5.4%) other causes ( keratectasia, bullous keratopathy, acne rosacea, interstitial keratitis, lagophthalmos, and rheumatoid arthtritis). The underlying cause of cornel melting was unknown in 4 eyes (10.8%). Combined PK was performed in18 of 37 eyes (48.7%), PK alone in 14 (37.8%) and patch graft in 5 (13.5%). Graft survival rate was 30/37 (81.1%) through follow-up. Anatomical integrity was achieved in 23 (92.0%) of 25 perforated corneas. Visual improvement was obtained in 28 eyes (75.6%). Visual acuity was ≥ 0.05 in 6 eyes (16.2%) preoperatively, it increased to 22 eyes  (59.4%) post-operatively.Conclusion: Therapeutic keratoplasty including PK and patch grafting is an effective surgical procedure in patients with severe corneal melting or perforation due to varying aetiologies. It restores the globe integrity also provides visual improvement.
Long-term survival of corneal transplants and visual outcomes among private patients of corneal surgeons in Metropolitan Manila (the Philippines)
Authors: Chan David Francis Fullon , Padilla Ma. Dominga B.
Published: January 2021

PURPOSE: There are currently no published studies on the outcomes of keratoplasty in the Philippines.  This study aimed to report graft survival rates at years 1, 3, and 5 after surgery, visual outcomes, and causes of graft failure among private patients of corneal surgeons in Metropolitan Manila receiving tissue from a single local eye bank in the period 2008-2012. 

DESIGN: Retrospective cohort, multicenter study.

METHODS: POPULATION: Private patients of Metro Manila corneal surgeons, receiving tissue from the Santa Lucia International Eye Bank of Manila in 2008-2012.  241 of 593 yielded sufficiently complete data sets. PROCEDURE: Donor and tissue characteristics, pre-op and latest follow-up characteristics/clinical findings were retrieved and processed. Data from the eye bank was merged with follow-up data from surgeons submitted March-October 2014. MAIN OUTCOME MEASURES: Survival rates at 1, 3, and 5 years; best-corrected visual acuity as of latest follow-up; causes of failure.

RESULTS:  1-year survival: 90.4%, 3-year: 71.5%, 5-year: ~52.7%. Overall, 43.5% had VA of 20/50 or better, and 25% counting fingers or worse, with variations across diagnoses.

CONCLUSION: Though small in sample size and response rate, survival trends parallel studies with larger populations elsewhere. Specific trends like favorable survival in keratoconus were consistent. Indications for surgery have changed little since 2005, but regraft has become the most common indication. Further data collection and completion are required for multivariate analysis on factors regarding survival.  Inflammation, infection, trauma, poor adherence are among the identified reasons for failure.
Influence of anterior chamber depth on postoperative refractive outcome in Chinese eyes
Authors: Wong Rachel SH , Ong Keith
Published: January 2021

Aim or Purpose: This study aims to evaluate the refractive surprise (RS) after cataract surgery with various intraocular lens (IOL) formulas in eyes with very shallow or deep anterior chamber depth (ACD).
Design: This is a prospective cohort study of patients from a private ophthalmology practice in Sydney.
Methods: Thirty-one patients who had their cataract surgery in 2014 were included. The cohort consists of 20 eyes with ACD < 2.8 mm and 25 eyes with ACD > 3.2 mm. Patients’ demographic variables and their predicted refractive outcomes using the SRK-T, Haigis, Holladay 1, and Holladay 2 IOL formulas were collected. Actual refractive outcomes were obtained from consultations at least one-month postoperatively. RS was calculated from the difference between predicted refraction outcome of IOL formulas and the actual postoperative refraction achieved.
Results: The linear correlations between ACD and RS were not significant (p > 0.05). In the group with ACD < 2.8 mm, the mean refractive surprise using SRK-T, Haigis, Holladay 1, and Holladay 2 formulas were -0.191 ± 0.541, -0.189 ± 0.444, -0.201 ± 0.449, and -0.154 ± 0.489 D, respectively. In the group with ACD > 3.2 mm, the mean refractive surprise using the IOL formulas were -1.364 ± 0.541, -1.420 ± 0.541, 0.027 ± 0.394, and -0.045 ± 0.343 D, respectively. 
Conclusion: The positive linear correlation between ACD and RS was weak. In eyes with ACD < 2.8 mm, the least RS was found with the Holladay 2 formula, while in eyes with ACD > 3.2 mm, this was found with Holladay 1.
Glaucoma and frequent flying
Authors: Ong Keith , Ong Leonard , Armellin Lillian Beatrice
Published: January 2021

To evaluate the possible impact of frequent flying on glaucoma progression.
Comparison of intraocular pressure and central corneal thickness in non-glaucomatous North- East Indian tribals versus general Indians
Authors: Natung Tanie , Goswami Prasanta Kumar , Keditsu Avonuo , Shullai Wakaru
Published: January 2021

Purpose: To compare the intraocular pressure (IOP) and central corneal thickness (CCT) of non-glaucomatous North-East (NE) Indian tribals and general Indians. 

Materials and methods: In a prospective, cross-sectional study, the IOP and CCT of non-glaucomatous NE Indian tribals (n = 50) and non-glaucomatous general Indians (n = 50) were compared. Glaucoma was ruled out by history, detailed ocular examinations, and investigations.

Results: There was very good correlation between the CCT and IOP values of right and left eyes (p = 0.940 and 0.847, respectively). The difference in the IOP values in the two groups was not statistically significant (p = 0.312 for Oculus Dexter [OD], p = 0.400 for Oculus Sinister [OS]). Similarly, the difference in the CCT values in the two groups was not statistically significant (p = 0.736 for OD and 0.613 for OS). The mean CCT and IOP OD for the whole population was 530.50 ± 35.42 μm and 13.80 ± 2.760 mmHg, respectively. By linear regression analysis, the IOP OD of the whole population had good correlation with CCT OD of the whole population (adjusted r2 = 0.084, p = 0.002), but not with age (adjusted r2=0.000, p=0.314) and sex (adjusted r2 = 0.010, p = 0.163). Similarly, CCT OD for the whole population did not have good correlation with age (adjusted r2 = -0.009, p = 0.762) and sex (adjusted r2 = -0.007, p = 0.603).

Conclusions: In this study of individuals with normal corneas and without glaucoma, no racial variation was found in the CCT and IOP values of the two groups. The IOP OD of whole population had good correlation with CCT, but not with age and sex. There was good correlation between OD and OS values of IOP and CCT.
Inter-rater reliability for visual acuity, refractive error, corneal reflex, and inter-pupillary distance among two masked optometrists in school children population
Authors: Prabhu Avinash , Pinto Alstreed Marita , Thalukdar Juthika , Ve Ramesh S.
Published: January 2021

Purpose: To observe the inter-rater reliability between the observers for visual acuity, refractive error, corneal reflex, and inter-pupillary distance.

Methods: A random subset of 50 students from primary (1st to 4th grade), higher primary (5th to 7th grade) and secondary school (8th to 10th grade), for a total of 150 students were selected by stratified sampling from the prevalence study VARES (Visual acuity, refractive error, and squint) performed among 1752 school children of Udupi district, India in 2013-2014. The Institutional Ethical Committee & District Health Administration board permission was acquired. There were two examiners: Examiner 1 (JT), a qualified optometrist with two years of experience, and Examiner 2 (MT), an optometry student. Examiners 1 and 2 performed a single measurement for visual acuity using the COMPlog computerized logMAR vision chart at 3 metres; Landolt C or Sloan letter optotypes used. Refractive error, corneal reflex, and inter-pupillary distance was measured by Plusoptix Power-refractor twice by Examiner 1 and thrice by Examiner 2; the average of each value was considered for analysis. Data was tested for normality using the Kolmogorov-Smirnov test. Statistical significance was considered p < 0.05. The agreement between the observers for the two procedures was traced by a Bland-Altman plot.

Results: The mean age of the students was 10.21 years (± 2.80 SD). The measurement of agreement for visual acuity (COMPlog) between the examiners was tested using Kappa statistics with 0.79 for OD, p < 0.05 and 1.0 for OS, p < 0.05 supported by Wilcoxon sign rank test showing 0.067 for OD and 0.564 for OS between the observers. The Bland-Altman plot also showed good agreement between the observers. Paired t-test for refractive error showed 0.117 (CI: -0.11­–0.10) for OD & 0.067 (CI: -0.005–0.157) for OS, with Bland-Altman plot showing good agreement between the observers. Paired t-test showed 0.323 for corneal reflex and 0.520 for inter-pupillary distance.

Conclusion: From the results we report that there is no interobserver variability for visual acuity, refractive error, corneal reflex and inter-pupillary distance in school screening with COMPlog and Plusoptix A09.
External dacryocystorhinostomy
Authors: Long Li Ying , Mohd Khialdin Safinaz , Ahmad Azli Nazila Binti
Published: January 2021

Aim: To analyse the epidemiological data, surgical technique, success rate, and complications of patients who underwent external DCR in Hospital Selayang from January 2015 to December 2016.

Method: Retrospective case series.

Results: A total of 21 eyes of 20 patients who underwent external DCR from January 2015 to December 2016 were identified and reviewed. There were 15 females (75%) and 5 males (25%). Age ranged from 5 to 75 years old, with a median age of 56 years old (IQR 23). Twelve patients presented with epiphora while eight patients presented with symptoms of dacryocystitis. One case was congenital, two were secondary nasolacrimal duct obstruction and the rest were primary nasolacrimal duct obstruction. All patients underwent external DCR under general anaesthesia. Silicone tube were inserted in 21 eyes, of which all were removed 3 months after the surgery except one patient whom had his tube dislodged accidentally. The overall success rate was 90.5% (n = 19), which was defined as no or minimal intermittent epiphora or no reflux on lacrimal irrigation at 12 months postoperative. There was one patient who had a cerebrospinal fluid leak treated successfully with intravenous antibiotics.

Conclusion: The surgical success rate for external dacryocystorhinostomy was comparable to that of the global success rate of external DCR. This is attributed to the application of surgical technique such as anterior suspended flap modification and posterior flap excision.
Feasibility, safety and clinical efficiency of optometric service pathways at primary and tertiary care level in Ampang, Malaysia
Authors: Hussin Duratul Ain , Hendicott Peter , Carkeet Andrew , Baker Philip , Chen Ai-Hong , Asnir Zalifa Zakiah , Zainal Abidin Zairah , Hussain Rusnah , Mokhtar Azlina
Published: January 2021

Aim: To evaluate feasibility, safety, and clinical efficiency of optometrists in conducting diabetic retinopathy screening and ocular health screening.

Methods: This was a prospective observational trial study of newly developed optometric service pathways established at a community health clinic for diabetic retinopathy screening and a hospital ophthalmology clinic for ocular health screening. The study was carried out to assess the feasibility and safety of eye examinations conducted by optometrists. Patients were examined by optometrists using a standard eye examination at both clinics and re-examined by ophthalmologists as the reference standard. Optometrists recorded diagnoses of ocular conditions and classified referral urgency for each patient and these were compared with the diagnoses made by ophthalmologists, who were masked to the optometrists’ findings.

Results: There was a high concordance of 87.0% (95% CI 80.4%-93.6%) for the diagnoses between the optometrists and ophthalmologists. Of 26 patients considered by the optometrists to need ophthalmology referral, 23 were agreed as such by the ophthalmologists, giving good agreement, κ = 0.76 (95% CI 0.53 -0.94) between the optometrists and ophthalmologists on referral classification. Agreement by the ophthalmologists for referral urgency classifications (very urgent/urgent or non-urgent) was very good (κ = 0.85, 95%CI 0.62-1.00).

Conclusions: Ocular health examination by optometrists using optometric-eyecare pathways is feasible and safe. Optometrists showed strong agreement with  ophthalmologists when diagnosing patients who had a range of ocular conditions. Optometrists were also able to triage referrals and their urgency accurately, suggesting that they could play an extensive role as primary eye care providers, thus reducing unnecessary referrals to ophthalmology clinics.
Validation of the WINROP screening algorithm among preterm infants in East Malaysia
Authors: Kadir Nurhayati Abdul , Ahmad Syed Shoeb , Ghani Shuaibah Abdul , Bastion Mae-Lyn Catherine
Published: January 2021

Objective: To prospectively validate the WINROP (Weight, Insulin-like growth factor 1, Neonatal, Retinopathy of Prematurity) screening algorithm (www.winrop.com) based on longitudinal measurements of neonatal body weights in predicting the development of severe retinopathy of prematurity (ROP) among preterm infants admitted to the neonatal intensive care unit of a tertiary care center in East Malaysia.

Methods: All premature infants of less than 32 weeks gestational age (GA) were included in this cohort. Their body weight was measured weekly from birth to 36 weeks postmenstrual age and entered into the computer-based surveillance system: WINROP. Infants were then classified by the system into high- or low-risk alarm group. The retinopathy findings were recorded according to Early Treatment for ROP criteria. However, the screening and management of infants were done according to the recommendations of the Continuous Practice Guidelines, Ministry of Health, Malaysia. The team members involved in screening and those recording the findings were kept blinded from each other.

Results: A total of 151 infants with median GA at birth of 30 weeks (interquartile range [IQR] Å} 2.1) and mean birth weight of 1,264 g (standard deviation Å} 271) were analyzed. High-risk alarm was signaled in 85 (56.3%) infants and 9 (6.6%) infants developed type 1 ROP. One infant in the low-risk alarm group developed type 1 ROP requiring laser retinal photocoagulation. The median time lag from the high-risk alarm signal to the development of type 1 ROP was 10.4 (IQR Å} 8.4) weeks.

Conclusion: In this cohort, the WINROP algorithm had a sensitivity of 90%, with negative predictive value of 98.5% (95% confidence interval) for detecting infants with type 1 ROP and was able to predict infants with ROP earlier than their due screening date. This study shows that a modified version of the WINROP algorithm aimed at specific populations may improve the outcome of this technique.
Comparative study of ocular manifestations of HIV infection at a tertiary care hospital in Maharashtra, India
Authors: Ambekar Sanjeevani , Badale Dhiraj , Kadam Dileep , Salvi Sonali
Published: January 2021

Purpose: We conducted the study to observe the change in infection patterns with the introduction of highly active antiretroviral therapy (HAART) and correlation of CD4 count with various ocular manifestations of acquired immune deficiency syndrome (AIDS).

Design: This was a prospective observational cohort study.

Methods: The study was conducted at a tertiary care teaching institute with established antiretroviral therapy (ART) centre. A total of 240 eyes of 120 ART-naive patients were enrolled. Ocular manifestations of these patients were observed and followed up for six months for any change with HAART.

Results: Out of 240 eyes, 24 showed ocular involvement (10%), of which human immunodeficiency virus (HIV) microangiopathy and molluscum contagiosum were most common. Out of the four cases of HIV microangiopathy, two cases demonstrated complete resolution after six months of ART. Only one of three cases of cytomegalovirus (CMV) retinitis showed healing after six months of ART.

Conclusions: Vision-threatening CMV retinitis and herpes zoster ophthalmicus can improve if specific treatment is initiated promptly. There is direct correlation between CD4 count, ocular manifestation, and prognosis of the patients; 33.33% of patients showed improvement in ophthalmic manifestations after HAART during a follow-up period of 6 months.
Eyelash in lacrimal punctum: demonstrating a negative pressure in the lacrimal sac
Authors: Verma Anil Kumar , Dogra Avantika , Tuli Rajeev
Published: January 2021

Eyelashes are normally arranged in two or three rows on the upper and lower eyelids. They are more numerous on the upper eyelid, with approximately 150 eyelashes being present on the upper and 75 on the lower eyelid. Eyelashes, like body hair, are shed regularly every 100 to 150 days. Usually, the shed eyelashes do not cause any symptoms.

However, the cilia may sometimes get misplaced and end up in the lacrimal puncta, meibomian gland orifice, subconjunctival space, and corneal stroma. An eyelash that gets misplaced into the punctum has the potential to cause additional problems. Once the eyelash enters the punctum, the barbs on the hair prevent it from being expelled.
Laser puncture of symptomatic primary iris pigment epithelial cyst causing hemeralopia: a rare case
Authors: Sharma Ram Lal , Pandey Mohan Lal , Sharma Vinod , Sharma Kalpana , Chaudhary Neha
Published: January 2021

Primary iris pigment epithelium cysts involve posterior surface of the iris and can occur at pupillary margin or anterior ciliary body. They may be stationary or progressive and sometimes regress spontaneously. These cyst can occasionally lead to angle-closure glaucoma, plateau iris syndrome and secondary pigment dispersion syndrome. A steadily growing cyst may disturb the vision by covering the visual axis and provoke an increase in intraocular pressure (IOP) or even inflammation if it touches the corneal endothelium. There are multiple management options in complicated situations. We report a case of a 17-year-old girl with unusual complaints of hemeralopia and dark-brown discolouration of pupils in both eyes. On examination, she had multiple pigment epithelial iris cysts at the pupillary margins, which were punctured with Nd:Yag laser, and the response was improvement in vision and hemeralopia without any pigment dispersion or IOP changes.
Dacryocystorhinostomy for the treatment of nasolacrimal duct obstruction: a pilot trial to assess impact on coexisting sinus symptoms
Authors: Mehta Ankur , Yi Wan , Ananda Arjuna , Ghabriel Raf
Published: January 2021

Purpose: To report on coexistent sinus symptoms in a population of patients who underwent endonasal dacryocystorhinostomy (DCR) surgery for nasolacrimal duct obstruction (NLDO) in a pilot study designed to test and refine methods and to estimate patient sample size for a larger multicentre randomised trial.

Methods: Ninety-four consecutive patients with NLDO who underwent endonasal DCR by three surgeons in both public and private practice over a two-year period were included in this study. Questionnaires were given preceding DCR surgery and at 10 weeks post-surgery. Sinus symptoms including sinusitis, nasal congestion, hyposmia, nasal discharge, and facial pressure were assessed in the questionnaire. All subjects underwent primary endonasal DCR and all patients underwent the same post-operative regimen.

Results: Questionnaire responses revealed that 48/94 (51%) patients had one or more sinus symptoms prior to DCR surgery. Ten-week post-DCR follow-up questionnaires were obtained from 77/94 (82%) patients. About 20/31 (65%) patients with one or more sinus symptoms prior to DCR surgery reported resolution of coexisting sinus symptoms by 10 weeks post-DCR surgery.

Conclusion: The data from this pilot study suggest that approximately half of patients attending for NLDO have coexisting sinus symptoms. There was some loss to follow-up. This pilot study highlighted the need for a validated patient questionnaire, longer length of follow-up, control groups for surgical intervention, and use of perioperative medications. Any clinical trial designed to assess the impact of endonasal surgery on sinus symptoms would need to enrol several hundred patients in order to reach a statistically valid conclusion.