Medical Hypothesis, Discovery, and Innovation in Ophthalmology最新文献

Background: This study aimed to compare the rate of endothelial cell loss (ECL) after penetrating keratoplasty (PKP) for optical versus therapeutic grafts at 3-, 6-, and 12-month postoperatively. Furthermore, the study aimed to investigate postoperative graft viability and the rate of graft rejection during the first year of follow-up for both indications.

Methods: This was a prospective, observational, comparative study that included patients who sought medical advice at the cornea outpatient clinic of Ain Shams University Hospitals, Cairo, Egypt. The study recruited 60 patients: group 1 included 30 transplanted corneas of 30 patients who underwent optical PKP for various indications, while group 2 included 30 transplanted corneas of 30 patients who underwent therapeutic PKP for unhealed, resistant infectious keratitis. Specular microscopy was performed for all patients at the 3-, 6-, and 12-month follow-up visits using Nidek CEM-530 specular microscopy. Postoperative clinical examinations were performed at the same follow-up visits to detect graft rejection.

Results: There were no statistically significant differences between the groups concerning the postoperative timing of graft clarity or the rate of ECL at 3- and 6-months postoperatively; however, the rate of ECL was significantly greater in group 2 than in group 1 at 12-months postoperatively (P = 0.03), although the difference was small from a clinical point of view. Moreover, there was no statistically significant difference between the groups in terms of the graft rejection rate.

Conclusions: Therapeutic PKP results were comparable to optical PKP with respect to graft viability, the rate of ECL, and the rate of graft rejection 1 year after grafting.

Background: The role of scleral contact lenses (SCLs) has increasingly expanded since the first lens was fitted more than a century ago. While it was initially prescribed for the management of severely compromised corneas, the indications for modern SCL use have expanded to include less severe diseases. In this review, we aimed to provide an up-to-date overview of the current indications, complications, and outcomes for the various types of SCLs.

Methods: In this narrative review, we thoroughly searched the PubMed/MEDLINE database for literature published from January 1980 to November 2021. Only relevant up-to-date English references were included. Furthermore, the figures in this manuscript were derived from our unit's patient documentation.

Results: Currently, SCLs can successfully be used to manage ocular surface diseases, visually rehabilitate irregular corneas, and correct irregular refractive errors. Although newer materials have yielded the same visual outcomes with fewer complications, these consequences still occur in approximately one-third of contact lens wearers, including difficulties in insertion and/or removal, discomfort or pain, and developing either halos, blurriness, or haze. Even though most of these complications are minor and can be easily treated, a good practice is essential to avoid sight-threatening complications such as microbial keratitis.

Conclusions: SCLs are indispensable in ophthalmic clinics. The development of better-quality SCLs has increased the number of indications and improved the achievable visual rehabilitation. The future of developing improvements in SCL design, materials, and fit, and the expansion of their indication range is promising.

Background: Surgical procedures are used as 1 of the main treatment modalities for pediatric glaucoma, even though progression may occur. In this study, we aimed to investigate the risk factors affecting the progression of pediatric glaucoma.

Methods: In this retrospective cohort study, we reviewed the medical records of patients diagnosed with pediatric glaucoma between April 2009 and March 2017. Pediatric glaucoma patients who underwent regular follow-up for at least 1 year were included. Demographics, intraocular pressure (IOP), central corneal thickness (CCT), axial length (AL), cup-to-disc ratio (C/D ratio), corneal diameter, type of glaucoma, age at time of diagnosis, and age at surgery were recorded. Progression was defined as an increase in AL > 2 mm, C/D ratio > 0.2, or corneal diameter > 1 mm during 1 year of follow-up.

Results: Eighty-three eyes from 46 patients were included: 37 eyes (45%) with primary congenital glaucoma (PCG), 46 eyes (55%) with secondary glaucoma, and 27 of these 83 eyes (32.5%) showed progression. Progression was comparable between eyes with PCG and secondary glaucoma (PCG, 22%; secondary glaucoma, 41%; P = 0.152). Age at the time of diagnosis and age at the time of the first surgery were significantly lower in the eyes with progression (P = 0.046 and 0.012, respectively). The mean (standard deviation) of surgeries in progressed versus non-progressed eyes was 1.88 (1.1) versus 1 (0.8) (P = 0.015). The frequency of comorbid systemic disease was significantly higher in patients with glaucoma progression (P = 0.043). The progressed and non-progressed eyes were comparable in terms of other demographic characteristics and ocular parameters (all P > 0.05).

Conclusions: Pediatric glaucoma patients who were younger at the time of diagnosis and the first glaucoma surgery and those with comorbid systemic disease are at higher risk of glaucoma progression. These findings are useful for clinicians when counseling parents of children with pediatric glaucoma about disease outcomes. However, future prospective studies with larger sample sizes and longer follow-up periods are needed to confirm our findings.

Background: The most frequent primary ocular malignancy in the western world is the uveal melanoma. While it mainly affects Caucasians, it is extremely uncommon among non-Caucasians. Continuous improvement in therapies for local treatment has allowed sparing of the eye, although this approach apparently does not improve survival. The present review aimed to explain different radiotherapy (RT) methods and compare the pros and cons of each method, along with the main complications that may be encountered in the treatment of uveal melanoma.

Methods: Relevant papers published between September 2009 and January 2021 were retrieved, reviewed, and screened. Four databases, including PubMed, MEDLINE, Google Scholar, and GeneCards, were searched for this purpose.

Results: Forty-one relevant articles were identified. Based on the selected papers, we highlighted the advantages and disadvantages of the different RT methods that have allowed sparing of the eye, even though they have not, as yet, improved survival. We listed a detailed comparison between therapies that allow an educated choice among the different available RT methods.

Conclusions: The choice of uveal melanoma management is determined by the location of the tumor and volume of the extraocular extent. At present, there is no gold standard for the management of all ocular melanomas, and each case should be approached individually. Therefore, classification is a valuable prognostic tool. Many cases in cT3-4 classification categories are treated by primary enucleation and conservative treatment follow-up, while in cT2 and most cT1 classifications (i.e., 3.1-6.0-mm tumor thickness), several forms of RT are used.

Background: Optical coherence tomography angiography (OCTA) is an advanced imaging modality that provides high resolution images at the level of different retinal layers. This study aime to evaluate choroidal neovascular membranes (CNVMs) secondary to age-related macular degeneration (AMD) quantitatively and qualitatively, according to their classification, morphological features, and flow areas, using OCTA.

Methods: In this descriptive, comparative, cross-sectional study, CNVMs were divided into 2 groups according to their classification as type 1 or type 2 neovascularization. Mied CNVMs were excluded from the study. The size (mm²) and the flow area (mm²) of the CNVMs were calculated via OCTA and the presence of the perivascular halo and loop anastomoses were analyzed. The morphological appearance of the CNVMs were classified as: medusa, sea-fan, lacy-wheel, glomerular, dead tree, and mature vascular networks.

Results: Of the 85 eyes assessed for eligibility, 45 eyes of 34 individuals with CNVM were enrolled in this retrospective study. Twenty-eight eyes had type 1 and 17 eyes had type 2 CNVMs. The mean size and flow area were greater in type 1 than in type 2 CNVMs (mean [standard deviation], 6.69 [4.54] and 3.61 [3.56] mm² versus 3.04 [1.98] and 1.77 [1.62] mm²; P = 0.044 and 0.046, respectively). Among the 22 eyes with type 1 CNVMs and the 9 eyes with type 2 CNVMs, 31 eyes had exudative membranes. Among the eyes with exudative CNVMs, 22 eyes had a perivascular halo and 22 eyes had loop anastomoses; this was significantly more than in the non-exudative eyes (P = 0.042 and 0.041, respectively). The lacy-wheel (38.7%) and dead tree (71.4%) patterns were the most frequent morphological appearance of the CNVMs in the exudative and non-exudative membranes, respectively.

Conclusions: OCTA provides objective documantation about CNVMs. A perivascular dark halo around CNVMs could be a criterion to define exudative membranes activity.

Background: This study was conducted to investigate ocular biometry parameters in cataract surgery candidates in northern Tehran, Iran using OA-2000 biometry device.

Methods: In this cross-sectional study, values of ocular biometry parameters, including axial length (AL), anterior chamber depth (ACD), mean corneal curvature (mean K), lens thickness (LT), corneal astigmatism (CA), and white-to-white (WTW) of 818 eyes with cataracts, were measured using the OA-2000 biometry device (Tomey, Nagoya, Japan). The participants were divided into si age subgroups, in 10-year intervals. Finally, the values of the biometry parameters were calculated, and the trend of changes was examined for both age and sex subgroups.

Results: The mean (standard deviation [SD]) of age of the participants was 63.82 (13.25) years. Mean (SD) of biometry parameters were as follows: AL, 23.36 (1.55) mm; ACD, 3.09 (0.40) mm; LT, 4.45 (0.55) mm; mean K, 44.51 (1.72) D; CA, 1.06 (0.94) D; and WTW, 11.81 (0.45) mm. Most of the parameters showed significant age-related changes in the total population. There was an increase in LT (P < 0.001) and mean K (P = 0.001), as well as a decrease in AL (P < 0.001) and ACD (P < 0.001) with age. Moreover, AL had a negative negligible correlation with LT (r = - 0.24; P < 0.001) and mean K (r = - 026; P < 0.001), as well as a weak positive correlation with ACD (r = + 0.44; P < 0.001).

Conclusions: Our study revealed that the mean values of most biometric parameters varied across age and sex subgroups. Moreover, most of the parameters showed significant age-related changes in the total population.

Background: The aim of this study was to develop a modified capsulorhexis technique featuring a new maneuver for the removal of subcortical fluid in fluid-filled mature cataracts to avoid high intralenticular pressure.

Methods: This prospective interventional study included 33 eyes with mature cataracts and evidence of subcapsular fluid spaces by slit lamp examination. For each patient, 20% mannitol was administered intravenously according to the bodyweight 1 h preoperatively. Under peribulbar anesthesia, a 2.2-mm main incision was made, and the anterior chamber was filled with a dispersive ophthalmic viscosurgical device. Using a bent-tip cystotome, a 2-mm curved incision was made in the center of the anterior capsule, which released subcortical fluid and was drained through compression of the posterior lip of the main incision using a spatula. Then, fine gentle milking in all quadrants around the puncture on the anterior lens capsule from the periphery toward the site of puncture using the blunt-edged spatula further assists drainage of subcortical fluid and breaks fine septa inside the lens to remove fluid from intralenticular fluid pocket collections.

Results: The study included 15 (45.5%) men and 18 (54.5%) women with a mean (standard deviation [SD]) of age of 63.2 (5.33) and 64.4 (6.21) years, respectively. The modified capsulorhexis technique was performed for 33 intumescent cataracts. Capsulorhexis was completed in all cases; capsulorhexis was easy in 31 (94%) eyes and difficult in 2 (6%) eyes. In the two difficult cases, radial extension occurred in one eye, and it was retrieved using the Little technique; the other case with radial tear was completed successfully using a retinal micro scissor from the other edge of the capsulorhexis until reaching an oval, continuous capsulorhexis.

Conclusions: This modified capsulorhexis technique with compression on the posterior lip of the main incision and capsule milking allowed for a safe, continuous curvilinear capsulorhexis. Further comparative studies are necessary to confirm our preliminary results.

Background: To correlate multifocal visual evoked potential (mfVEP) findings with static automated perimetry (SAP) and spectral-domain optical coherence tomography (SD-OCT) in eyes with primary open- angle glaucoma (POAG).

Methods: This cross-sectional study included a consecutive sample of 40 eyes of 40 patients with POAG. The participants underwent a complete ophthalmologic assessment, axial length (AL) measurement, and assessments with SAP, SD-OCT, and mfVEP.

Results: POAG cases were aged 49.70 (14.16) years (mean [SD]) and most were females (n = 24, 60%). For eyes of patients with POAG, the mfVEP upper-ring signal-to-noise ratio (SNR) showed a significant negative correlation with best-corrected logMAR visual acuity (r = - 0.33; P = 0.038), and a significant positive correlation with the superior hemifield of the visual field (VF) and the inferior-quadrant retinal nerve fiber layer (RNFL) thickness (r = + 0.34; P = 0.030; r = + 0.51; P < 0.001, respectively). Similarly, the mfVEP lower-ring SNR showed a significant negative correlation with best-corrected logMAR visual acuity (r = - 0.36; P = 0.024) and a significant positive correlation with the inferior hemifield of the VF and superior quadrant RNFL thickness (r = + 0.55; P < 0.001 and r = + 0.70; P < 0.001, respectively).

Conclusions: mfVEP is a promising tool for objective assessment of the VF in patients with POAG, as it is positively correlated with the VF and OCT RNFL thickness. Future longitudinal studies with a larger sample size and a specific glaucoma subtype, along with multiple follow-up evaluations, are warranted to confirm our preliminary results.

Background: Angiogenesis causes severe vision loss in patients with exudative or wet forms of age-related macular degeneration (AMD). The pathogenesis involves upregulation of several proangiogenic factors, particularly the vascular endothelial growth factor (VEGF). Contrary to the pathogenesis of exudative AMD, molecular events leading to the development of dry AMD remain unclear. Dry AMD is characterized by loss of the retinal pigment epithelium (RPE). The mechanism that triggers RPE cell loss remains unclear. Choriocapillaris development is absent in mice with RPE-specific deletion of VEGF. Moreover, in later life, background VEGF secretion promotes the survival of the RPE and maintains choriocapillaris integrity.

Hypothesis: We hypothesized that reduced synthesis of VEGF (hypo-angiogenesis) or abnormalities in its receptors, VEGF receptor-1 (VEGFR1) and VEGFR2, may be involved in the pathogenesis of non-exudative AMD or dry AMD. If the concept of hypo-angiogenesis as a driver for dry AMD is proven, treatment with VEGF or induction of angiogenesis could be considered. Similar attempts at therapeutic angiogenesis have been actively investigated in cardiac and limb ischemia.

Conclusions: The reasons for a patient developing exudative AMD or dry AMD remain poorly understood. Nevertheless, targeting increased VEGF production in patients with exudative AMD using anti-VEGF drugs is highly efficacious in preserving vision. Similarly, dry AMD may be a manifestation of reduced VEGF synthesis (hypo-angiogenesis) and subsequent decreased RPE cell survival. Experimental studies exploring the possibility of reduced VEGF secretion and/or increased receptor resistance/abnormality could pave the way for clinical trials of angiogenesis to treat dry AMD.

Background: With advances in medical facilities and increased survival of premature infants, the prevalence of retinopathy of prematurity (ROP) has increased. This study aimed to determine the frequency of ROP and its associated risk factors.

Methods: This descriptive-analytical, retrospective study included all premature infants with a birth weight (BW) ≤ 2,500 g and/or gestational age (GA) ≤ 35 weeks who were referred to Imam Khomeini Hospital in Ahvaz, Iran, for ROP screening over a 7-year period from April 2013 to April 2020. Demographic criteria, associated risk factors, and findings of eye examinations were collected and analyzed.

Results: Of the 812 at-risk infants screened, 807 met the inclusion criteria. ROP was observed in 316 (39.0%) of the 807 premature infants, with types I and II in 142 (45.0%) and 174 (55.0%) infants, respectively. The mean (SD) GA (29.6 [2.5] weeks versus 30.7 [2.5] weeks) and BW (1,203.6 [382.8] g versus 1,333.5 [386.5] g) were significantly lower in infants with ROP than in those without ROP (both P < 0.001). GA (r = 0.80; P < 0.001) and BW (r = 0.85; P < 0.001) had a strong positive correlation with ROP, and the correlation increased as GA and BW decreased (all P < 0.001). Associated risk factors in infants with ROP, in order of frequency, were oxygen therapy (22.8%), respiratory distress (16.1%), phototherapy (14.6%), blood transfusion (5.7%), apnea (4.1%), mechanical ventilation (1.6%), and intraventricular hemorrhage (0.9%). Multivariate regression analyses showed low GA and BW (both P < 0.05) as independent predictors of ROP.

Conclusions: The frequency of ROP in premature infants was slightly higher than the average range reported for domestic and foreign statistics. Low BW and GA were independent predictors of ROP.