Journal of Ophthalmic and Vision Research
Year:2018 | Volume:13 | Issue:1|Papers Count:19

As eye care specialists, we inevitably encounter patients with concomitant keratoconus (KCN) and cataracts. It is known that patients with KCN are more likely to develop cataracts than subjects without KCN and do so at a younger age than the general population. [1] The incidence of KCN is also much higher than what was known in the older literature. A recent review has shown that the incidence of keratoconus is 1: 7500 with a prevalence of 1: 375. This is 5‑ 10 fold higher than that previously reported in the literature. [2] In addition, new diagnostic modalities such as Scheimpflug imaging tomography and high resolution optical coherence tomography (OCT) have enhanced our capability to identify eyes with subclinical and early KCN much earlier than before. With the advent of potentially new stabilizing procedures such as collagen cross‑ linking and corneal rings, many patients with mild to moderate KCN will eventually require cataract surgery and most likely demand toric intraocular lenses for less dependency on glasses and contact lenses...

Purpose: To evaluate the magnitudes and axis orientation of anterior corneal astigmatism (ACA) and posterior corneal astigmatism (PCA), the ratio of ACA to PCA, and the correlation between ACA and PCA in the different stages of keratoconus (KCN). Methods: This retrospective case series comprised 161 eyes of 161 patients with KCN (104 men, 57 women; mean age, 22. 35 ± 6. 10 years). The participants were divided into four subgroups according to the Amsler‑ Krumeich classification. A Scheimpflug imaging system was used to measure the magnitude and axis orientation of ACA and PCA. The posterior‑ anterior corneal astigmatism ratio was also calculated. The results were compared among different subgroups. Results: The average amounts of anterior, posterior, and total corneal astigmatism were 4. 08 ± 2. 21 diopters (D), 0. 86 ± 0. 46 D, and 3. 50 ± 1. 94 D, respectively. With‑ the‑ rule, against‑ the‑ rule, and oblique astigmatisms of the posterior surface of the cornea were found in 61 eyes (37. 9%), 67 eyes (41. 6%), and 33 eyes (20. 5%), respectively; corresponding figures in the anterior corneal surface were 55 eyes (32. 4%), 56 eyes (34. 8%), and 50 eyes (31. 1%), respectively. A strong correlation (P ≤ 0. 001, r = 0. 839) was found between ACA and PCA in the different stages of KCN; the correlation was weaker in eyes with grade 3 (P ≤ 0. 001, r = 0. 711) and grade 4 (P ≤ 0. 001, r = 0. 717) KCN. The maximum posterior‑ anterior corneal astigmatism ratio (PCA/ACA, 0. 246) was found in patients with stage 1 KCN. Conclusion: Corneal astigmatism in anterior surface was more affected than posterior surface by increasing in the KCN severity, although PCA was more affected than ACA in an early stage of KCN.

Purpose: To determine the factors that influence the endothelial cell density (ECD) of donor grafts after Descemet stripping automated endothelial keratoplasty (DSAEK). Methods: This retrospective, interventional case series comprised 77 eyes of 64 patients who underwent DSAEK. Confocal microscopy was performed at the final follow‑ up examination to evaluate the endothelial cell count, cell morphology, and graft thickness. Univariate and multiple linear regression analyses were used to investigate recipient‑ , donor‑ , surgical‑ , and postoperative related variables capable of influencing graft endothelial cell counts after DSAEK. Results: The mean patient age was 62. 3 ± 15. 6 years; patients were followed‑ up for 26. 2 ± 20. 9 months postoperatively. Forty‑ six eyes (59. 7%) underwent stand‑ alone DSAEK; 31 eyes (40. 3%) underwent DSAEK combined with cataract surgery. The donor trephination size was 8. 0 ± 0. 21 mm. The mean donor age was 30. 4 ± 11. 2 years, and the mean preoperative endothelial cell density was 3127. 4 ± 315. 1 cells/mm 2, which decreased to 1788. 6 ± 716. 5 cells/mm 2 postoperatively (P < 0. 001). The mean postoperative central graft thickness was 102. 4 ± 31. 6 µ m. Univariate analysis revealed that postoperative ECD was significantly associated with death to preservation time (P = 0. 046), graft thickness (P = 0. 016), follow‑ up duration (P = 0. 005), and graft non‑ attachment (P = 0. 049). Multiple regression analyses identified graft thickness (β = 10. 62, P = 0. 003) and follow‑ up duration (β = ‑ 22. 09, P = 0. 001) as the significant characteristics influencing postoperative ECD. Conclusion: The primary predictors of ECD after DSAEK were graft thickness and duration of follow‑ up. Surgeons’ requests for ultrathin DSAEK donor grafts to improve visual outcomes might not have the desired postoperative outcome with respect to ECD.

Purpose: To evaluate refractive status and identify predictors of surgical success following a combined silicone oil removal/cataract surgery with intraocular lens (IOL) implantation procedure. Methods: In this single‑ armed, retrospective study, we reviewed patients who underwent vitreoretinal surgery followed by a combined silicone oil removal/cataract surgery procedure between 2009 and 2013. Preoperative data included patient demographics, refractive status, IOL power, and axial length (measured with the IOL Master). Postoperative data were obtained from the 8‑ week follow‑ up visit and from the last follow‑ up visit attended that included refractive error (RE) evaluation (e. g., myopic, hyperopic, and astigmatic). Associations between variables and refractive status were examined. Blindness was defined as a best‑ corrected visual acuity (BCVA) worse than 3/60. Results: Nighty‑ eight eyes were ultimately included in analyses. Following surgery, 37. 0% of eyes achieved BCVA better than 6/18. The incidence of blindness (BCVA worse than 3/60) was reduced from 47. 0% before surgery to 17. 3% after surgery. Additionally, 33. 7% of eyes did not require refractive correction. Forty‑ two percent of eyes were under‑ corrected (>0. 5 D hyperopia) following surgery. Age, gender, silicone oil viscosity, axial length, IOL type, initial vitreoretinal pathology, surgeon, and IOL calculation formula were not significantly associated with surgical outcomes (all P > 0. 05). Conclusion: A combined silicone oil removal/cataract surgery with IOL implantation procedure restored functional vision in approximately one‑ third of cases. However, nearly half of patients were under‑ corrected. Unfortunately, we did not identify any factors that predicted surgical success.

Purpose: To investigate the effect of Ozurdex (dexamethasone intravitreal implant) on multifocal electroretinography (mfERG) findings during the treatment of macular edema secondary to the central retinal vein occlusion (CRVO). Methods: Fifteen eyes of 15 patients who were treated with Ozurdex implant due to CRVO‑ related macular edema were included in this study. Best corrected visual acuity (BCVA), central macular thickness (CMT), and mfERG evaluations were performed for all patients before injection of Ozurdex. After the injection, BCVA and CMT were measured at months 3 and 6 and mfERG test was performed at month 6 for all patients. Results: Pre‑ implantation mfERG P wave amplitude values of r1, r2, r3, r4 and r5 were 57. 8 ± 14. 8, 25. 1 ± 10. 6, 17. 2 ± 7. 3, 12. 0 ± 5. 0 and 7. 1 ± 3. 6 nV/deg² , respectively. They increased to 72. 9 ± 33. 2, 31. 2 ± 9. 3, 22. 6 ± 7. 6, 15. 6 ± 7. 1 and 10. 9 ± 5. 7 nV/deg² , respectively, at month 6. However, these increases were not statistically significant (all P > 0. 05). Pre‑ implantation mfERG r1, r2, r3, r4 and r5 P wave implicit times were 40. 1 ± 10. 9, 39. 4 ± 3, 38. 4 ± 3. 4, 38. 2 ± 3. 1 and 39. 3 ± 2. 2 ms, respectively and these values were measured as 38. 9 ± 8. 2, 38. 4 ± 4. 7, 37 ± 3. 8, 37. 5 ± 4. 6 and 37. 7 ± 4. 7 ms at 6 months. Although there were reductions in P wave implicit times in all rings, they were not statistically significant (all P > 0. 05). Conclusion: In this prospective study, we found that the Ozurdex implant had no effect on mfERG findings 6 months after insertion for treatment of CRVO‑ related macular edema.

Purpose: To describe the efficacy of intravitreal bevacizumab for the treatment of type 1 retinopathy of prematurity (ROP) in zone I. Methods: Preterm infants with type 1 ROP in zone I (zone I ROP, any stage with plus disease or zone I ROP, stage 3 without plus disease) were enrolled in this prospective study. Intravitreal bevacizumab (0. 625 mg/0. 025 ml) was injected under topical anesthesia. Patients were followed weekly for 4 weeks and then biweekly till 90 weeks gestational age. Results: Seventy eyes of 35 patients with type 1 ROP in zone I were enrolled. At a gestational age of 90 weeks, ROP regressed with complete or near‑ complete peripheral retinal vascularization, in 82. 9% of eyes after a single injection and in 92. 9% of eyes after up to two injections. In five eyes (7. 1%), ROP progressed to stage 4B or 5, so surgical management was required. There were no major complications such as endophthalmitis, cataract, or vitreous hemorrhage after injection. Conclusion: Intravitreal bevacizumab injection is an effective method for the management of patients with Zone I ROP requiring treatment; however, some cases may progress to more advanced stages and require surgical management. Close monitoring for recurrence or progression is necessary. Eyes with persistent zone I ROP may progress to advanced stages when treated with intravitreal bevacizumab injection and re‑ treatment may be needed.

Purpose: We aimed to present the ophthalmic manifestations of neuro‑ metabolic disorders. Methods: Patients who were diagnosed with neuro‑ metabolic disorders in the Neurology Department of Mofid Pediatric Hospital in Tehran, Iran, between 2004 and 2014 were included in this study. Disorders were confirmed using clinical findings, neuroimaging, laboratory data, and genomic analyses. All enrolled patients were assessed for ophthalmological abnormalities. Results: A total of 213 patients with 34 different neuro‑ metabolic disorders were included. Ophthalmological abnormalities were observed in 33. 5% of patients. Abnormal findings in the anterior segment included Kayser– Fleischer rings, congenital or secondary cataracts, and lens dislocation into the anterior chamber. Posterior segment (i. e., retina, vitreous body, and optic nerve) evaluation revealed retinitis pigmentosa, cherry‑ red spots, and optic atrophy. In addition, strabismus, nystagmus, and lack of fixation were noted during external examination. Conclusion: Ophthalmological examination and assessment is essential in patients that may exhibit neuro‑ metabolic disorders.

Purpose: To measure the choroidal thickness by enhanced depth imaging optical coherence tomography (EDI‑ OCT) in normal eyes. Methods: In a prospective case series, 208 eyes of 104 normal Iranian subjects were enrolled. Complete ophthalmic examination was performed. Inclusion criteria were best corrected visual acuity (BCVA) ≥ 20/20, ≤ ± 1 diopter of refractive error in either spherical or cylindrical components, normal intraocular pressure (IOP) and no systemic or ocular diseases. The choroidal thickness was measured by EDI‑ OCT subfoveally, and 1500 µ m and 3000 µ m nasal and temporal to the fovea. Results: Mean age was 34. 6 ± 9. 8 years (range, 18– 57 years). Mean subfoveal choroidal thickness was 363 ± 84 µ m. Choroidal thickness was 292 ± 76 and 194 ± 58 µ m at 1500 and 3000 µ m nasal to the fovea, respectively, and 314 ± 77 and 268 ± 66 µ m at 1500 and 3000 µ m temporal to the fovea, respectively. There was no statistically significant difference in the choroidal thickness between sexes and laterality of the eyes. Choroidal thickness at fovea (P < 0. 001) and at all extrafoveal locations decreased significantly for every 10 years increase in age. Conclusion: In normal Iranian subjects participating in this study, mean choroidal thickness was comparable with other reports.

Purpose: To investigate visual performance during reading under different illumination sources. Methods: This experimental quantitative study included 40 (20 females and 20 males) emmetropic participants with no history of ocular pathology. The participants were randomly assigned to read a near visual task under four different illuminations (400‑ lux constant): compact fluorescent light (CFL), tungsten light (TUNG), fluorescent tube light (FLUO), and light emitting diode (LED). Subsequently, we evaluated the participants’ experiences of eight symptoms of visual comfort. Results: The mean age of the participants was 19. 86 ± 1. 09 (range: 18– 21) years. There was no statistically significant difference between the reading rates of males and females under the different illuminations (P = 0. 99); however, the reading rate was fastest among males under CFL, and among females under FLUO. One way analysis of variance (ANOVA) revealed a strong significant difference (P = 0. 001) between males and females (P = 0. 002) regarding the visual performance and illuminations. Conclusion: This study demonstrates the influence of illumination on reading rate; there were no significant differences between males and females under different illuminations, however, males preferred CFL and females preferred FLUO for faster reading and visual comfort. Interestingly, neither preferred LED or TUNG. Although energy‑ efficient, visual performance under LED is poor; it is uncomfortable for prolonged reading and causes early symptoms of fatigue.

Purpose: To study the demographic profile, severity and causes of visual impairment among registered patients in a tertiary care hospital in north Kolkata, eastern India, and to assess the magnitude of under‑ registration in that population. Methods: This is a retrospective analytical study. A review of all visually impaired patients registered at our tertiary care hospital during a ten‑ year period from January 2005 to December 2014, which is entitled for certification of people of north Kolkata, eastern India (with a population denominator of 1. 1 million), was performed. Overall, 2472 eyes of 1236 patients were analyzed in terms of demographic characteristics, cause of visual impairment, and percentage of visual disability as per the guidelines established by the government of India. Results: Male patients (844, 68. 28%; 95% confidence interval [CI], 65. 69‑ 70. 87) registered more often than female patients (392; 31. 72%, P = 0. 0004). The registration rate for visual impairment was 11. 24 per 100, 000 per annum; this is not the true incidence rate, as both new patients and those visiting for renewal of certification were included in the study. Optic atrophy was the most common cause of visual impairment (384 eyes, 15. 53%; 95% CI, 14. 1‑ 16. 96). Conclusion: Commonest cause of visual impairment was optic atrophy followed by microphthalmos. Under‑ registration is a prevalent problem as the registration system is voluntary rather than mandatory, and female patients are more likely to be unregistered in this area.

Cyclodestructive techniques have been a treatment option for refractory glaucoma since its first use in the 1930s. Over the past nine decades, cyclodestruction has advanced from the initial cyclodiathermy to micropulse transscleral cyclophotocoagulation (MP‑ TSCPC) which is the current treatment available. Complications associated with cyclodestruction including pain, hyphema, vision loss, hypotony and phthisis have led ophthalmologists to shy away from these techniques when other glaucoma treatment options are available. Recent studies have shown encouraging clinical results with fewer complications following cyclophotocoagulation, contributing greatly to the current increase in the use of cyclophotocoagulation as primary treatment for glaucoma. We performed our literature search on Google Scholar Database, Pubmed, Web of Sciences and Cochrane Library databases published prior to September 2017 using keywords relevant to cyclodestruction, cyclophotocoagulation and treatment of refractory glaucoma.

Pregnancy leads to significant changes in the body, which potentially affect the retina. Pregnancy can induce disease, such as that seen in hypertensive retinopathy and choroidopathy. It can cause exudative retinal detachments in the HELLP syndrome (hemolysis, elevated liver enzymes and low platelets), disseminated intravascular coagulation (DIC), and thrombotic thrombocytopenic purpura (TTP), and provoke arterial and venous retinal occlusive disease. Pregnancy may also exacerbate pre‑ existing retinal disease, such as idiopathic central serous chorioretinopathy (ICSC) and diabetic retinopathy. Special consideration needs to be exercised when treating pregnant patients in choosing medications, as well as in selecting diagnostic modalities and surgical methods.

Glaucoma is the leading cause of irreversible blindness and vision loss in the world. Although intraocular pressure (IOP) is no longer considered the only risk factor for glaucoma, it is still the most important one. In most cases, high IOP is secondary to trabecular meshwork dysfunction. High IOP leads to compaction of the lamina cribrosa and subsequent damage to retinal ganglion cell axons. Damage to the optic nerve head is evident on funduscopy as posterior bowing of the lamina cribrosa and increased cupping. Currently, the only documented method to slow or halt the progression of this disease is to decrease the IOP; hence, accurate IOP measurement is crucial not only for diagnosis, but also for the management. Due to the dynamic nature and fluctuation of the IOP, a single clinical measurement is not a reliable indicator of diurnal IOP; it requires 24‑ hour monitoring methods. Technological advances in microelectromechanical systems and microfluidics provide a promising solution for the effective measurement of IOP. This paper provides a broad overview of the upcoming technologies to be used for continuous IOP monitoring.

Purpose: To report two cases of spontaneous Descemet’ s membrane detachment (DMD) and dehiscence following penetrating keratoplasty (PK). Case Reports: Spontaneous DMD or Descemet’ s membrane (DM) dehiscence following PK is a rare occurrence. Here, we describe two cases of such an occurrence following PK arising from the graft– host interface. A possible causative relation between DMD/dehiscence and DM– stromal interface attachment is suggested. Conclusion: DMD and dehiscence after PK can be explained by the peripheral thinning of DM and possible changes to the recently characterized anchoring zone of interwoven collagen fibers and proteoglycans at the Descemet– stroma interface.

Purpose: We report the variability in flow angiogram during the course of branch retinal artery occlusion (BRAO) in a case imaged by optical coherence tomography angiography (OCTA). Case Report: OCTA was performed in a patient with BRAO at initial examination and 6 hours later. Initially, the occluded retinal artery and its branches were not detected on OCTA whereas a slow perfusion was present on fluorescein angiography. Six hours after initial examination, flow was detected on OCTA image in the previously occluded artery. Conclusion: This case confirmed the relevance of using OCTA in monitoring BRAO and showed that capillaries with a very slow flow are not visible on OCTA angiograms. It emphasizes that non‑ perfusion on OCTA should be interpreted with caution.

Purpose: To describe a case of primary atypical orbital lipomatous tumor (ALT). Case Report: A 35‑ year‑ old man presented with a two‑ month history of left eye proptosis and vertical diplopia. His visual acuity was 20/30 OD and 20/60 OS. External examination showed proptosis and downward displacement of the left eye with mild lid erythema. Extraocular movements were reduced in the left eye, with 10% and 70% motility in upgaze and abduction/adduction, respectively. Imaging showed a mass (22 × 16 × 46 mm) in the superior left orbit that infiltrated the orbital fat and the superior rectus muscle. A biopsy of the mass showed mature adipose tissue intermingled with fibrous zones of hyperchromatic stromal cells with nuclear atypia. Fluorescence in situ hybridization analysis demonstrated positive amplification for MDM2/CEP12. The MDM2 to CEP12 ratio was 5: 7. A diagnosis of ALT was confirmed. An orbital exenteration was recommended, which the patient declined. Conclusion: Although rare, the differential for unilateral proptosis with or without diplopia should include orbital liposarcomas including the ALT subtype. Imaging, biopsy, staining, and/or FISH analysis for proto‑ oncogenes can assist with diagnosis and staging, while the standard treatment is exenteration.

Dear Editor, We report a case of a 69‑ year‑ old man with right eye conjunctival rhinosporidiosis involving the lateral rectus muscle. The patient presented with a progressive swelling of the temporal conjunctiva of the right eye and intermittent binocular diplopia for four months. There was no history of diminished vision, epiphora, and photophobia. The patient was a swimmer...

Dear Editor, I read the photo essay titled “ Unilateral Myelinated Retinal Nerve Fibers” with interest. [1] The authors reported a case of unilateral extensive myelination with amblyopia, with partial improvement after occlusion therapy. However, there was no comment about the status of the optic nerve head. Several reports have suggested that myelinated nerve fibers are associated with optic nerve dysplasia. [2] Williams proposed that retinal myelination leads to a decrease in the ganglion cells, which causes optic nerve hypoplasia, resulting in decreased visual acuity. [3] Holland and Anderson postulated that the myelinated nerve fibers induce overall disorganization of neural elements, leading to a disc anomaly, which is responsible for refractory amblyopia...

Dear Editor, We would like to thank Dr. Mohan for his comments and for sharing his interesting case with us...