Some diopsid flies have sexually dimorphic eye stalks that are assumed to require considerable nutrition for growth but are advantageous in competition and courtship. According to the handicap theory, the eye span in some dimorphic species serves as a reliable signal of individual quality to an opponent. However, it is not well understood how well eye span represents energy source storage. In this study, we focused on two species: Sphyracephala detrahens, which has weak dimorphism, and Cyrtodiopsis dalmanni, which has moderate dimorphism. We found that the eye stalks of the former species contained more fat bodies than those of the latter species. When the flies were starved, the fat body cells in the eye stalks underwent autophagy. A strong positive correlation was consistently found between eye span and starvation tolerance for S. detrahens, while a weak correlation was found for C. dalmanni. Furthermore, starvation decreased the contest winning rate between S. detrahens pairs with similar eye spans. These findings suggest that the presentation of resource holding potential may be larger than the actual storage ability and that the fidelity of nutritional storage signaling varies; the signal presented by S. detrahens is more reliable than that presented by C. dalmanni.
We measured stereoacuity using TNO test on 25 patients without fixation disparity (FD) and compared the result with other 25 patients exhibited FD related to visual stress. All patients were presbyopes of ages ranging from 40 to 80 years, with visual acuity 6/6 or better in each eye, free from ocular diseases and generally healthy. The results showed statistically significant difference in the stereoacuities measured between the groups (Mann-Whitney U = 181.0, p < 0.01), suggesting that FD significantly reduced stereoacuity. Although the correlation between the magnitudes of FD and stereothreshold is statistically not significant (Spearman's r(s) = 0.33, p>0.01), elimination of FD using prisms correction statistically improved stereoacuity (Wilcoxon's Z = 2.43, p<0.01). The findings conclude that visual stress manifested as FD causes deficit in stereoperformance measurable with the TNO test and can be improved by prism correction.
Retinoblastoma, the most common primary intraocular malignancy of childhood, usually presents in the first three years of life. Atypical presentation of retinoblastoma can masquerade as virtually any ocular or orbital pathology, which may lead to diagnostic dilemmas especially in the presence of other systemic diseases. We report a 20-month-old boy who was diagnosed with coronary aneurysm as a complication of Kawasaki disease, and presented with sudden left eye redness. His mother noticed the presence of white pupillary reflex three months earlier. Atypical acute ocular presentation secondary to Kawasaki disease was initially suspected, but the presence of multiple calcification and mild proptosis on imaging suggested characteristics of advanced retinoblastoma. Histopathological examination of the enucleated eye, which revealed a classical rosette pattern appearance, confirmed the diagnosis. Atypical presentations of retinoblastoma are usually associated with advanced disease. The presence of other systemic conditions further complicates the diagnosis. Early diagnosis is important to reduce the mortality and morbidity.
A giant retinal tear (GRT) is a full-thickness neurosensory retinal break that extends circumferentially around the retina for three or more clock hours in the presence of a posteriorly detached vitreous. Its incidence in large population-based studies has been estimated as 1.5% of rhegmatogenous retinal detachments, with a significant male preponderance, and bilaterality in 12.8%. Most GRTs are idiopathic, with trauma, hereditary vitreoretinopathies and high myopia each being causative in decreasing frequency. The vast majority of GRTs are currently managed with a pars plana vitrectomy; the use of adjunctive circumferential scleral buckling is debated, but no studies have shown a clear anatomical or visual advantage with its use. Similarly, silicone oil tamponade does not influence long-term outcomes when compared with gas. Primary and final retinal reattachment rates are achieved in 88% and 95% of patients, respectively. Even when the retina remains attached, however, visual recovery may be limited. Furthermore, fellow eyes of patients with a GRT are at higher risk of developing retinal tears and retinal detachment. Prophylactic treatment under these circumstances may be considered but there is no firm evidence of its efficacy at the present time.
This work was conducted to study the ability of bacterial and fungal isolates from keratitis cases in Upper Egypt to produce enzymes, toxins, and to test the isolated fungal species sensitivity to some therapeutic agents.
Intraorbital foreign bodies (IOrbFB) are associated with both sight and life threatening injuries. We report a case of an IOrbFB associated with retrobulbar hemorrhage and injury of the frontal sinus in an 11 year-old boy, after history of fall from the tree. Imaging studies revealed a metallic foreign body (FB) in the orbit and fracture of the walls of the frontal sinus. The usual entry route of an IOrbFB is either through the eye or orbital walls and extremely rare through the paranasal sinuses. This is the first reported case of a FB entering the orbit through the frontal sinus.
Objective: To determine the prevalence of eye diseases and visual impairment among new patients at the eye clinic of Hospital Sultan Haji Ahmad Shah, Temerloh, Pahang.
Method: In this cross-sectional prospective study, 1081 new patients were examined over a period of six months. Age, gender, ethnicity, visual acuity and diagnosis were noted from the medical records.
Results: Out of 1081 examined, 607 (56.1%) were males, 783 (72.4%) were Malays. The mean age of patients was 45.2 years (ranging from one month to 91 years). Cataract (248, 22.9%) was the most common eye disease, followed by retinal diseases (124, 11.5%) and ocular trauma (106, 9.8%). Majority of the patients (48) suffering from ocular trauma had foreign body cornea. In 85 premature infants screened for retinopathy, 19 showed different stages of retinopathy of prematurity. Visual impairment was noted in 89 (8.2%) patients, severe visual impairment in 12 (1.1%) and blindness in 35 (3.2%); vision could not be determined in 85 premature infants (7.9%). Cataract was singled out as the cause of severe visual impairment in 11 out of 12 patients.
Conclusion: Health education at primary health centres and availability of eye specialists in all the district hospitals will facilitate the rehabilitation of visually impaired and blind persons by providing early treatment for eye problems (specifically prescription for spectacles, medical treatment and cataract surgery with intraocular lens implantation).
Keywords: Visual impairment, cataract, diabetic retinopathy, glaucoma, refractive errors, ocular trauma, conjunctivitis
Study site: Eye clinic, Hospital Sultan Haji Ahmad Shah, Temerloh, Pahang, Malaysia
This article describes the analysis of electromagnetic energy absorption properties of models of the human eye with common visual disorders. The investigation addresses two types of visual disorders, namely hyperopia (or farsightedness) and myopia (or nearsightedness). Calculations were carried out using plane multilayered method with common wireless communication frequencies of 900, 1800, and 2450 MHz. The effect of wireless radiation on the eye is studied by calculation of the specific absorption rate (SAR) in three different eye models. The results of the simulations confirmed the anticipated and more complex relationship between absorption and structural variations of the eye at these frequencies.
An exponential contrast stretching (ECS) technique is developed to reduce the charging effects on scanning electron microscope images. Compared to some of the conventional histogram equalization methods, such as bi-histogram equalization and recursive mean-separate histogram equalization, the proposed ECS method yields better image compensation. Diode sample chips with insulating and conductive surfaces are used as test samples to evaluate the efficiency of the developed algorithm. The algorithm is implemented in software with a frame grabber card, forming the front-end video capture element.
Adult ocular stem cells have the potential to restore vision in patients previously deemed incurable. This review summarizes strides in stem cell research and stumbling blocks that must be overcome to enable treatment viability in ophthalmology.
Blunt ocular trauma may result in expulsion of the intraocular lens in a patient who has undergone cataract surgery. This case report describes a patient who presented with an extrusion of intraocular lens following blunt ocular trauma post-operatively. The authors emphasise the importance of patient counselling and protection of the operated eye after surgery.
We present the case of a 32-year-old woman who, 10 months after abdominoperineal resection and total mesorectal excision for a locally advanced mucinous adenocarcinoma of the rectum, presented with local recurrence and metastases to the breast, spine, the left eye and orbit. Following surgery, due to the patient's personal reasons, adjuvant chemoradiation was not given. The patient died 2 months later, with disseminated cancer. To the best of our knowledge, breast as well as ocular metastasis in a patient with mucinous adenocarcinoma of the rectum has never been reported and, therefore, needs to be documented.
We present two siblings from a consanguineous Malaysian family with multiple skeletal abnormalities, anterior segment anomalies of the eye and early lethality. These features are consistent with a syndrome first described by Al-Gazali and we provide further delineation of the syndrome.
We describe a case of extensive ocular injury secondary to an electronic cigarette (e-cigarette)-related explosion. The explosion was the result of modifications made to a heating element of the e-cigarette device by a non-professional. Extensive ocular injuries that result from an explosion of an e-cigarette device can potentially cause significant and permanent visual impairment.
For the reading task, contrast reserve is defined as the ratio of the letter contrast of the printed letters, to the reader's contrast threshold. Acuity reserve is the ratio of the print size used for the reading task, to the reader's visual acuity. The effects of low contrast reserve on reading performance were investigated at various magnifications, ranging from 3x to 7.5x, with the field of view systematically controlled. Eye movements were recorded whilst normally sighted subjects read using the magnifiers. It was shown that with adequate contrast reserve, increasing the field of view improved the reading rate because of the resulting increase in forward saccade length. Conversely, reducing the contrast reserve slowed the reading rate by decreasing the length of forward saccades and increasing the mean fixation duration, suggesting that the perceptual span is reduced at low contrast reserve. This study also shows that when the contrast reserve is low, providing magnification higher than that required for letter recognition (that is, increasing the acuity reserve) will not improve the reading performance. Furthermore, even when the contrast reserve was high, reading rates were lower for the magnifications of 5x and higher, because increases in saccade length do not match those of the retinal image size at these magnifications.
A cross-sectional prevalence study amongst a nursing home elderly population was carried out at Rumah Sri Kenangan, Seremban, Negeri Sembilan between June 1995 until June 1996. A total of 204 cases of 60 years and older were examined in order to determine the ocular morbidity amongst them. It was found that 47.5% had low vision and 19.1% were legally blind. Cataract was found to be the leading cause of low vision and blindness occurring in 81.4% and 74.3% respectively. Glaucoma occurred in 1% of those who had low vision and none due to macular degeneration or diabetic retinopathy. The magnitude of visual impairment and blindness in this nursing home is high but is preventable and avoidable.
Naso-lacrimal duct tumours are uncommon and present with epiphora and swelling. Since the naso-lacrimal duct is embedded in bone for the majority of its anatomical length, the late presentation of proptosis is due to orbital extension of the tumour. Radical surgical treatment is necessary to establish clear margins and facilitate reconstruction.
Three consecutive cases of lacrimal gland carcinoma seen at the University Hospital during a twelve-year period are presented. One case was unusual, presenting at the age of sixteen years and developing metastases to the lungs. Adenoid cystic carcinoma is the commonest type of lacrimal malignancy and its clinico-pathological features and surgical management are discussed.
Between 1st January 1999 and 31st December 2000, 152 patients (156 eyes) with open-globe injuries were treated in the Department of Ophthalmology, Hospital Sultanah Aminah, Johor Bahru. The majority were male (88.2%), Malay (63.2%), from the Johor Bahru district (51.3%) and aged between 21 and 30 years (23.7%). Most injuries were workplace-related (41.4%). Lens injury, retinal detachment, endophthalmitis, intraocular foreign bodies and phthisis occurred in 40.4%, 15.4%, 14.7%, 12.2% and 11.5% of eyes respectively. A favourable visual outcome occurred in 55.4% of eyes. Prognostic factors for visual outcome include presenting visual acuity, relative afferent pupillary defect, wound location, lens injury, retinal detachment and endophthalmitis.