Indications and outcomes of pediatric penetrating keratoplasty: A retrospective observational study

Background

Pediatric corneal transplantation can be indicated in congenital and acquired conditions. Challenges include preoperative evaluation, multiple intraoperative obstacles, and postoperative problems in follow-up and management. This study was aimed at identifying the indications and clinical outcomes of pediatric penetrating keratoplasty (PKP) in Jordan.

Methods

This retrospective cohort study was conducted in Amman, Jordan. Using the hospital's electronic database, all medical records of patients aged < 18 years who underwent PKP between January 2004 and October 2019 were reviewed. Preoperative evaluations included best-corrected distance visual acuity (BCDVA) and anterior and posterior segment examinations. Postoperative complications, BCDVA, and graft survival were examined 1 year postoperatively.

Results

A total of 149 cases of pediatric PKP were performed on 141 eyes of 118 patients with an age mean ± standard deviation (SD) of 11.44 ± 4.97 years at the time of surgery. Acquired non-traumatic corneal pathologies accounted for 65.8% of indications for PKP. The most frequent indication was advanced keratoconus (55.7%). Preoperative and 1-year postoperative BCDVAs significantly differed (P < 0.001), with 111 (74.5%) patients showing improved BCDVA, 12 (8.05%) patients showing worsened BCDVA, and 26 (17.45%) patients showing no change in BCDVA. The overall 1-year graft survival rate was 80.54%.

Conclusions

This was the largest study in Jordan involving pediatric patients who underwent PKP for various indications, showing a significant improvement in BCDVA, with a high survival rate at 1 year. Future studies with longer follow-up periods could provide stronger evidence for surgical outcomes and graft survival. Further, the option of lamellar keratoplasty in the pediatric age group should be assessed.

Worldwide inequality in access to full text scientific articles: the example of ophthalmology

Background

The problem of access to medical information, particularly in low-income countries, has been under discussion for many years. Although a number of developments have occurred in the last decade (e.g., the open access (OA) movement and the website Sci-Hub), everyone agrees that these difficulties still persist very widely, mainly due to the fact that paywalls still limit access to approximately 75% of scholarly documents. In this study, we compare the accessibility of recent full text articles in the field of ophthalmology in 27 established institutions located worldwide.

Methods

A total of 200 references from articles were retrieved using the PubMed database. Each article was individually checked for OA. Full texts of non-OA (i.e., “paywalled articles”) were examined to determine whether they were available using institutional and Hinari access in each institution studied, using “alternative ways” (i.e., PubMed Central, ResearchGate, Google Scholar, and Online Reprint Request), and using the website Sci-Hub.

Results

The number of full texts of “paywalled articles” available using institutional and Hinari access showed strong heterogeneity, scattered between 0% full texts to 94.8% (mean = 46.8%; SD = 31.5; median = 51.3%). We found that complementary use of “alternative ways” and Sci-Hub leads to 95.5% of full text “paywalled articles,” and also divides by 14 the average extra costs needed to obtain all full texts on publishers’ websites using pay-per-view.

Conclusions

The scant number of available full text “paywalled articles” in most institutions studied encourages researchers in the field of ophthalmology to use Sci-Hub to search for scientific information. The scientific community and decision-makers must unite and strengthen their efforts to find solutions to improve access to scientific literature worldwide and avoid an implosion of the scientific publishing model. This study is not an endorsement for using Sci-Hub. The authors, their institutions, and publishers accept no responsibility on behalf of readers.

Iris and ciliary body cysts and phakic intraocular lenses

Phakic intraocular lenses are used to correct refractive errors. The procedure is predictable and potentially reversible. The procedure is not free of complications though. The occurrence of iris cyst after implantation of a phakic intraocular lens was not described previously in the literature. We describe two cases of iris cysts in the presence of a phakic intraocular lens; the first case describes a cyst which was not present prior to the anterior chamber phakic intraocular lens implantation. The second case describes a hidden iris cyst that affected the posterior chamber phakic intraocular lens position and lead to glaucoma.

Optimizing Genipin Concentration for Corneal Collagen Cross-Linking: An ex vivo Study

PURPOSE

Studying genipin variable concentrations, treatment durations, and delivery methods as a substance to increase corneal stiffness by inducing corneal collagen cross-linking (CXL).

MATERIALS AND METHODS

100 bovine corneas treated with different genipin concentrations (0.1, 0.5, and 1%) and treatment durations (15 min, 40 min, 2 h, and 3 days) through different delivery methods compared to 10 controls treated with riboflavin/UV. Histology examination, enzymatic digestion with collagenase and thermal differential scanning calorimetry were performed on the different samples.

RESULTS

Bovine corneas soaked in 0.5% genipin morphologically showed 4.7% CXL in comparison to 5.6% in controls (p < 0.05). Corneas treated with topical 0.5% genipin, by a 140-µL drop applied hourly for 2 h, showed 7% corneal CXL. Corneas treated with topical genipin 0.5% for 30 min, 1 and 2 h showed 54 ± 6, 40 ± 7, and 39 ± 9% enzymatic degradation, respectively, in comparison to controls (74%). Corneas treated with 0.5% genipin for 1, 2, and 8 h showed higher thermal denaturation resistance (Td values of 64.9 ± 0.3, 64.7 ± 0.0 and 67.3 ± 0.9), respectively, in comparison to the control group (64.6 ± 0.5) (p < 0.05).

CONCLUSIONS

Genipin 0.5%, in a 140-µL drop applied hourly for 2 h, showed better potential to enhance corneal stiffness and stability through inducing CXL.

Endophthalmitis Following Pediatric Cataract Surgery: An International Pediatric Ophthalmology and Strabismus Council Global Perspective

PURPOSE

To compile international data on the risk factors, diagnosis, and treatment of endophthalmitis following pediatric cataract surgery.

METHODS

An e-mail containing a link to an online survey was sent to all members of the American Association for Pediatric Ophthalmology and Strabismus. The questionnaire examined the incidence, risk factors, treatment, outcomes, and prophylaxis of endophthalmitis following pediatric cataract surgery around the world.

RESULTS

Two hundred thirty-seven ophthalmologists answered the questionnaire. Eight ophthalmologists (3.4%) encountered 22 cases of endophthalmitis following pediatric cataract surgery during their practice. Most patients with endophthalmitis following pediatric cataract surgery were 2 to 4 years of age (36.4%). An intraocular lens was implanted in 59.1% of cases, most of which were acrylic intraocular lenses (53.8%). The main presenting symptoms were photophobia (50%) and pain (40.9%). The most common signs were conjunctival injection (36.4%) and hypopyon (31.8%). The final visual acuity was counting fingers or worse in 86% of cases. The most common cultured organism was Staphylococcus aureus (31.8%). The most common management of endophthalmitis following pediatric cataract surgery was a combination of intravitreal, systemic, and topical antibiotics (36.4%). Most ophthalmologists (68.2%) administered prophylactic intracameral antibiotic treatment during surgery and 50% used vancomycin.

CONCLUSIONS

Endophthalmitis following pediatric cataract surgery is an uncommon, multifactorial complication with poor visual prognosis. Efforts directed at minimizing its risk, such as treating potential predisposing systemic conditions, improving sterilization techniques, optimizing operative conditions to reduce complications and surgery duration, and using subconjunctival and intracameral antibiotics, decrease its incidence. Early postoperative evaluation, subsequent follow-up visits, and keeping a high index of suspicion should facilitate the recognition of endophthalmitis following pediatric cataract surgery to avoid delaying treatment. [J Pediatr Ophthalmol Strabismus. 2018;55(1):23-29.].

Ferrara ring segments implantation for treating keratoconus

AIM

To investigate the efficacy of Ferrara rings (FR) implantation in the treatment of keratoconus.

METHODS

It was a retrospective case series descriptive study. The sample was comprised of 50 patients 79 eyes diagnosed with progressive keratoconus. This included 24 (48%) males and 26 (52%) females between the age of 13 and 44 years. All participants underwent surgical implantation of FR in the period between January 2009 and September 2010 at Jordan University Hospital. Thorough ophthalmologic examinations were applied to measure vital variables for each pathological condition before and after surgery.

RESULTS

Findings indicated an overall significant postoperative improvement in both uncorrected visual acuity (UCVA) and best spectacle corrected visual acuity (BSCVA) throughout follow up visits. Moreover, results illustrated a significant decrease in spherical equivalent (SE) and keratometric readings (lower, higher and the average).

CONCLUSION

Surgical intervention strategies are being frequently developed to meet the needs of patients with keratoconus. The implantation of Ferrara rings has proven to be a safe and feasible alternative procedure for the treatment of mild-moderate keratoconus especially for patients with contact lenses intolerance. We have found that this procedure has improved visual outcomes in all eyes studied. Nevertheless, further research is needed to investigate long term outcomes.

High-performance liquid chromatographic determination of floctafenine and its major metabolite, floctafenic acid in plasma

A simple, rapid and selective high-performance liquid chromatographic method for the determination of floctafenine and its major metabolite, floctafenic acid, in plasma is reported. Plasma samples were purified using the mobile phase as a protein precipitant. The supernatant containing parent compounds and diazepam (internal standard) were eluted from a 5 micron C 18 reversed-phase column at ambient temperature. The mobile phase consisted of 0.05 M sodium acetate:acetonitrile: methanol (200:100:100 v/v/v) adjusted to pH 5 and pumped isocratically at a flow rate of 1.5 ml/min. The effluent was monitored at 350 nm. Quantification was achieved by the measurement of the peak-height ratio of each drug to the internal standard. The mean percentage recoveries from plasma samples spiked with floctafenine and floctafenic acid ranged from 88.13 to 101.93%. Detection limits were 100 ng/ml for floctafenine and 50 ng/ml for floctafenic acid. The coefficients of variation (RSD, %) for within-day and day-to-day analysis were less than 8%.

Bioequivalence of two oral dosage forms prepared from different polymorphic modifications of tenoxicam

The bioavailability of two pharmaceutical dosage forms formulated using different polymorphs of tenoxicam were compared. Serum levels of TNX were analysed using high performance liquid chromatography. The pharmacokinetic parameters were estimated following the oral administration of a single dose (20 mg) of the drug as two different polymorphs to 12 healthy volunteers. The differences between formulations were statistically insignificant.

Analysis and bioequivalency study on two tablet formulations of co-trimoxazole

This paper describes an analytical procedure for simultaneous quantification of trimethoprim (TMP) and sulphamethoxazole (SMZ) in serum. Serum samples were rendered alkaline with glycine-sodium hydroxide buffer (pH 9.1) and extracted with ethyl acetate. The reconstituted sample was analysed using reversed-phase C-18 column high-performance chromatography. The mobile phase consisted of 75% triethyl ammonium acetate buffer, 20% methanol and 5% acetonitrile. The analytes were monitored at 289 nm and tetroxoprim was used as an internal standard. The maximum values for intra-day coefficients of variation (CV) for TMP-and SMZ were 5.7 and 2.1%, respectively. Interday CV values were 6.4 and 2.2%, respectively. The method was used to compare the bioavailability of two tablet formulations in terms of their pharmacokinetic parameters following oral administration of the tablets to 18 volunteers.

Bioequivalency studies on tablet formulation of tetroxoprim and sulphadiazine

The paper describes a comparative bioavailability study on two tablet formulations containing 100 mg of tetroxoprim and 250 mg of sulphadiazine. The comparison was based on the estimated pharmacokinetic parameters from time--serum concentration profiles obtained following the administration of the tablets to 12 healthy volunteers. Statistical analysis performed on the parameters showed that the differences are statistically insignificant and the formulations are bioequivalent.

High-performance liquid chromatographic determination of methotrexate in plasma

A procedure for the determination of methotrexate in human plasma is reported. The analysis involved extraction of methotrexate as an ion pair in ethyl acetate. Reconstituted residue was analyzed using reverse phase C-18 column and a mobile phase consisting of acetate buffer (87%), methanol (6.5%), and acetonitrile (6.5%). The methotrexate recovery range was 95-97%. Theophylline was used as internal standard with a recovery of 96%. The intraday coefficient of variation for the assay ranged from 1.8-3.0%, while interday variation coefficient range was 3.5-3.7%. The method is selective, reproducible, and covers a wide range of methotrexate concentrations in patient's plasma.

Bioequivalency of ranitidine tablets

The bioavailability of two brands of ranitidine tablets was studied in 10 healthy volunteers. Formulation factors were compared by performing disintegration, dissolution and content uniformity tests. Plasma concentrations of ranitidine were measured using a sensitive and precise high pressure liquid chromatographic (HPLC) procedure. Pharmacokinetic parameters were determined for both formulations and included: Cmax, AUCt, AUC infinity, tmax, t1/2 and the terminal rate of elimination (k). Statistical analysis revealed that differences between the brands were not significant. The two formulations can be considered to be bioequivalent.

High-performance liquid chromatographic analysis of ranitidine in plasma and urine

A high-performance liquid chromatographic method for the analysis of ranitidine in plasma and urine is described. Plasma samples were extracted with dichloromethane while urine samples were injected directly after dilution. The mobile phase consisted of: 0.05 M ammonium acetate buffer containing 0.01 M octane sulphonate, 5.3%; methanol, 31.6%; and acetonitrile, 63.1%. Detection was carried out at 330 nm. Metoclopramide was used as the internal standard. Peak height ratios were measured. Absolute recovery from plasma was 83-85%. Within and between day coefficients of variation ranged from 0.79 to 2.42% and 1.09-2.95% respectively. Plasma and urine samples from a healthy volunteer were analysed.