Journal of Ophthalmic and Optometric Sciences
Volume:2 Issue: 1, Winter 2018

To evaluate the effect of myopic photorefractive keratectomy (PRK) on color vision, contrast sensitivity and higher order aberrations (HOAs). Patients and

This prospective study was performed on 46 eyes of 23 patients with 3 to 6 diopter of myopia/myopic astigmatism undergoing PRK. Color vision using FransworthMunsell 100 hue test (©2011 X-Rite Inc., Michigan, U.S) and contrast sensitivity using CSV-1000 (Vector Vision, Dayton, OH) were tested preoperatively and 2 and 6 months postoperatively. HOAs were assessed using Zernike analysis map of Pentacam (OCULUS Optikgeräte GmbH, Germany) preoperatively and 6 months postoperatively.

No significant change was observed in color vision following PRK. Contrast sensitivity function was also preserved except for an increase in 12 cycles per degree (cpd) spatial frequency 6 months after surgery (P = 0.04). Total HOAs and primary spherical aberrations (total, anterior and posterior surface) increased significantly (P < 0.001), however, primary coma showed no statistically significant change 6 months after surgery compared to baseline values. Induced total HOAs significantly correlated with change in primary vertical coma and total, anterior, and posterior primary spherical aberration. No significant correlation was found between the changes in contrast sensitivity, color vision and HOAs with the amount of preoperative sphere and cylinder.

PRK with an aspheric profile in moderate myopia/ myopic astigmatism does not affect color vision and contrast sensitivity at 3, 6 and 18 cpd spatial frequencies. It increases total HOAs and spherical aberration, but not coma. It remains a good option for refractive correction of moderate.

To evaluate the visual evoked potentials in patients with spastic cerebral palsy. Patients and

Fifty children with spastic cerebral palsy were selected. They were all male in age range of l0 to 13 years. The visual evoked potential using the checker board stimulation method was used to evaluate the visual pathway of patients. Latency (msec) and amplitude (μv) of VEP, P100 peak was measured for all participants. The same procedure was repeated for fifty age and sex matched healthy individuals as the control group. The results obtained in two groups were compared to look for probable differences.

There was no statistically significant difference between the case and control groups regarding their mean age. The mean latencies for VEP, P100 peak in the case and control groups were 115 ± 15 msec and 95 ± 5 msec respectively (P < 0.001). The mean amplitudes for VEP, P100 peak were 82 ± 0.7 μv and 5 ± 2.15 μv in the case and control groups respectively (P < 0.001) .

Visual evoked potential is a suitable technique to check the visual pathway of patients with spastic cerebral palsy. The pathway shows pathological changes in patients with spastic cerebral palsy, which can be monitored using visual evoked potential recording.

To evaluate the repeatability of biomechanical readings by Corvis ST (Wetzlar, Germany) in healthy eyes and its relation with age and sex.

Three consecutive measurements were performed on 100 eyes of 100 patients using the Corvis ST. Various parameters including first and second applanation length, first and second applanation velocity, first and second applanation time, peak distance, radius, deformation amplitude, corrected and noncorrected intraocular pressure (IOP), central corneal thickness (CCT), Corvis ST biomechanical index (CBI), and tomography and biomechanical index (TBI) were derived from the Corvis ST readings. Repeatability of each parameter and their correlation with age and sex were evaluated.

The mean IOP, CCT, CBI and TBI were 15.47 ± 2.24 mm Hg, 541.24 ± 38.90 μm, 0.048 ± 0.13 and 0.138 ± 0.17 respectively. Intra class correlation coefficient (ICC) for CCT, second applanation velocity and deformation amplitude were 0.985, 0.809 and 0.825 respectively. ICC was less than 0.8 for all other parameters. The device-specific readings showed no significant relationship with age and sex.

The Corvis ST showed high repeatability for CCT, second applanation velocity, and deformation amplitude parameters. No relation between Corvis ST readings and age or sex was observed.

To evaluate the accuracy of glaucomatous optic neuropathy diagnosis in a resident based hospital.

Four hundred twenty eyes of 210 patients underwent ocular examination including intra ocular pressure and optic nerve head measurements by third and fourth year residents and suspect cases were referred to a glaucoma specialist for validation. After reevaluation by the specialist a comparison between these two examination results was performed to evaluate the over diagnosis of disease by residents.

In this prospective study, eighteen eyes out of 420 evaluated eyes were diagnosed as either glaucoma suspect (14 eyes) or glaucoma (4 eyes) by residents. After reevaluation by the glaucoma specialist only one eye had suspect optic nerve head which was referred for optic nerve head imaging. All other eyes had normal optic nerve head and retinal nerve fiber layer in examination by the specialist.

The results of the present study indicate a high rate of glaucomatous optic neuropathy over diagnosis by third and fourth year ophthalmology residents. Further studies are needed to find if this over diagnosis is related to poor training or anxiety among residents to miss a real case of glaucoma.

To evaluate the effect of soft contact lens induced myopia and hyperopia on optic nerve head measurements of normal eyes using spectral domain optical coherence tomography (SD-OCT).

This cross sectional study was performed on 114 emmetropic eyes of 57 participants. Each participant underwent a complete ophthalmic examination including determination of best-corrected visual acuity, intraocular pressure, dry and cycloplegic refraction as well as axial length measurement. SDOCT measurement was performed in all ayes while different levels of refraction strength were induced by wearing soft contact lenses of five different diopters (- 10.00, - 5.00, Plano, + 5.00, + 10.00).

The mean measured thicknesses of retinal nerve fiber layer were 123.29 ± 10.56 micrometer, 123.17 ± 11.61 micrometer, 122.77 ± 11.61 micrometer, 123.37 ± 11.15 micrometer and 123.42 ± 11.45 micrometer in contact lens induced high myopia, moderate myopia, emmetropic, moderate hyperopia, and high hyperopia groups, respectively (P = 0.721). Also, corresponding evaluations for mean rim area (P = 0.781), mean optic disc area (P = 0.601), mean cup area (P = 0.53), and mean cup to disc area ratio (P = 0.414) showed no statistically significant difference.

Our findings indicate that refractive error variation at the corneal plane caused by contact lens wear has no significant effect on thickness of retinal nerve fiber layer, disc area, cup area, rim area and mean cup to disc area ratio measured by SD-OCT.

Sickle cell disease is one of the most prevalent hemoglobinopathies in the world. In Iran, sickle cell disease is more common in southern parts of the country such as Khuzestan province. Retinopathy is the most representative ocular complication of sickle cell disease. Sickle cell retinopathy is characterized by the vaso-occlusion of capillary beds and is classified in two types of proliferative and non-proliferative according to presence or absence of vascular proliferation in fundus. In non-proliferative sickle cell retinopathy, the retinal changes do not involve neovascularization as they do in proliferative sickle cell retinopathy. The two most severe complication of proliferative sickle cell retinopathy are vitreous hemorrhage and retinal detachment, which may lead to visual loss. Identification and prompt referral of these patients has a critical role in prevention of irreversible visual loss. Newer imaging modalities such as ultra–wide field fluorescein angiography, spectral domain optical coherence tomography and optical coherence tomography angiography are now available. These techniques can detect the sickle cell retinopathy in its early stages. In this review, we briefly discuss the manifestations, diagnosis and management of sickle cell retinopathy.

Sjogren’s syndrome is one of the most common autoimmune diseases. It may exist as either a primary syndrome or as a secondary syndrome associated with other autoimmune diseases such as rheumatoid arthritis and systemic sclerosis. Patient with Sjogren’s syndrome have certain visual system involvements with dry eye being the most common type. These patients may also exhibit certain pathological changes in their retina and visual pathway. Here we report the electrophysiological recording including visual evoked potential, electro- retinography and electrooculography findings in a patient with Sjogren’s syndrome.

To report a case of acute intra corneal cleft in a patient undergoing ocular massage following Ahmed valve implantation. Case Report: Acute intra corneal cleft occurred in a patient following the use of ocular massage to reduce IOP and bleb formation after Ahmed glaucoma valve insertion. Previous history of the patient was Fuchs heterochromic iridocyclitis without any report of trauma to his eye or any other ophthalmic disorders. The slit lamp examination revealed huge localized corneal bulla formation with a diameter of 3 mm in the superior mid peripheral corneal region in the right eye just after ocular massage, which persisted in the 6 months of follow up.

Digital ocular massage might cause the occurrence of intra corneal cleft. Although this might be a very rare complication, we should consider it as an adverse effect of ocular massage.