Long-Term Follow-Up of Combined Photorefractive Keratectomy and Corneal Crosslinking in Keratoconus Suspects

Purpose

To present the long-term outcomes of photorefractive keratectomy (PRK) combined with accelerated corneal cross-linking (CXL) for refractive error correction in a series of keratoconus suspects.

Setting

University practice.

Design

Retrospective case series.

Methods

A series of patients with topographic findings suspicious for keratoconus underwent simultaneous PRK and prophylactic accelerated CXL (5 minutes with intensity of 18 mW/cm²) for the correction of their refractive error. The results were recorded for more than 4 years postoperatively.

Results

Ten eyes of 5 patients were included. Mean follow-up was 58.2 months (range from 54 to 62 months). Mean age at presentation was 25 years (range from 22 to 32 years). Mean spherical equivalent (SE) refraction was −2.76 (standard deviation [SD] 0.97D, range from −1.25 to −4.00 diopters [D]), while mean central corneal thickness was 511μm (SD 13μm, range from 485 to 536 μm). At last, follow-up 9 out of 10 eyes had SE refraction within ± 0.50D and all eyes had SE within ± 1.00D. None of the eyes lost any line of corrected distance visual acuity (CDVA), whereas 1 eye gained one line of CDVA. All eyes demonstrated stability of their results during the follow-up period.

Conclusion

Simultaneous PRK followed by prophylactic accelerated CXL (PRK plus) appeared to be a safe and effective option for the correction of the refractive error in this series of keratoconus suspect patients, without compromising corneal stability for up to 5 years postoperatively.

Surgical and Perioperative Considerations for the Treatment of Cataract in Eyes with Glaucoma: A Literature Review

Cataract surgery in the presence of glaucoma poses certain challenges that need to be addressed to offer the maximum benefit without complications. In this paper, we are reviewing the preoperative assessment, surgical options, the planning, and postoperative care. Cataract surgery can help reduce the intraocular pressure alone or combined with MIGS. When performed in patients with glaucoma, it can transiently increase the intraocular pressure and later on decrease the IOP to levels lower than the postoperative. The preoperative IOP and biometric characteristics are the main predictors of the postoperative course of IOP. The combination of cataract surgery with trabeculectomy remains controversial, in terms of best timing of each operation.

Combined Corneal Wedge Resection And Corneal Cross-Linking For Pellucid Marginal Degeneration: A First Report

Background

Advanced pellucid marginal degeneration is a debilitating disease that warrants the use of surgery when the visual acuity is reduced and contact lenses are not tolerated anymore. It is traditionally managed with corneal transplantation, however alternative surgical options exist. Corneal wedge resection allows for good visual rehabilitation without the risks of tissue rejection. However topographical and refractive results are in some instance fluctuating. We present here the use of corneal cross-linking in order to stabilize the parameters on the long term.

Case presentation

We present here the case of a 53 years old patient with bilateral advanced pellucid marginal degeneration. As he is now intolerant to contact lenses a surgical option is offered to him. In order to avoid using donated tissue through corneal grafting we decide to perform a sectorial lamellar crescentric wedge excision of the thinner inferior part of the cornea involving the pellucid marginal degeneration and suture it. The first eye shows initial good results however after few months regression is observed. The second eye is then treated with the same surgical technique combined with cornea cross-linking. Long-term follow-up shows stabilization and absence of regression in the second eye up to eight months after the surgery.

Conclusion

Combining corneal cross-linking with corneal wedge resection in the case of advanced pellucid marginal degeneration patients could be a good option in order to stabilize topographical and refractive results and reduces the risk of regression.

Acute glufosinate-based herbicide treatment in rats leads to increased ocular interleukin-1β and c-Fos protein levels, as well as intraocular pressure

Glufosinate is a common herbicide with neurotoxic effects, leading to seizures, convulsions and memory loss. Glufosinate indirectly induces glutamate toxicity by inhibiting glutamine synthesis in astrocytes. Here, we studied the acute toxic effects of a glufosinate-based herbicide in rat optic nerve at three doses (40, 80 or 120 μM, equal to 714 or 21 mg/kg bw/day). Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), urea, glucose, calcium, as well as creatinine concentrations were analyzed after 24, 48 and 72 h treatment. Intraocular pressure (IOP) (expressed as the average of both eyes) was measured with a rebound tonometer. Interleukin-1β (IL-1β) and c-Fos expression were determined by immunohistochemistry. The results established that the glufosinate-based herbicide significantly increased IL-1β and c-Fos immunopositivity in the optic nerve (p < 0.05), concomitant with increased IOP. These results suggest that commercial formulations of glufosinate acutely affect the optic nerve.

Correlation between age and corneal edema in pediatric patients with Peters anomaly

PURPOSE

To evaluate corneal edema in different-aged pediatric patients with Peters anomaly and to correlate in vivo with ex vivo histopathologic findings.

METHODS

A retrospective cross-sectional study was performed. The medical records of patients diagnosed with Peters anomaly who underwent examination under anesthesia (EUA) between 2011 and 2015 were reviewed. Eyes in which central corneal thickness (CCT) measurements were taken were included. The thickest point in the CCT pachymetric map was used to objectively quantify corneal edema. Correlation between CCT and age was calculated. Additionally, a retrospective review of histopathologic studies of excised corneal buttons from pediatric eyes with Peters anomaly between 2011 and 2015 was performed.

RESULTS

Eighteen eyes of 12 children were included. Mean age was 14 ± 15 months, and mean CCT was 842 ± 304 µm. A significant inverse correlation was noted between the CCT and the age of the patients, with lower CCT values in older children (r = 0.6; P = 0.01). Seven excised corneal buttons that underwent penetrating keratoplasty were reviewed. All corneal buttons showed absence of Descemet membrane and localized absence of endothelium. However, three specimens showed presence of corneal endothelium in areas of absent or attenuated Descemet membrane.

CONCLUSIONS

In Peters anomaly, the CCT decreases with age, possibly due to a decrease in corneal edema. Histopathologic studies show cases of endothelial expansion in areas of absent or attenuated Descemet membrane. This may contribute to improved endothelial function and decreased edema with age.

Comparison of endothelial/Descemet's membrane complex thickness with endothelial cell density for the diagnosis of corneal transplant rejection

Purpose:

This study compared the effectiveness of endothelial/Descemet’s membrane complex thickness obtained using high-definition anterior segment optical coherence tomography with endothelial cell density obtained using confocal microscopy as diagnostic tools in predicting corneal transplant rejection.

Methods:

This observational, prospective, cross-sectional study evaluated penetrating keratoplasty grafts. Slit lamp examination organized the grafts into healthy or rejecting grafts. Grafts were scanned using both high-definition anterior segment optical coherence tomography and confocal microscopy. Central corneal thickness, endothelial/Descemet’s membrane complex thickness, endothelial cell density, and coefficient of variation were each compared with the clinical status. Descemet’s rejection index, defined by endothelial/Descemet’s membrane complex thickness divided by central corneal thickness multiplied by 33, further compared endothelial/Descemet’s membrane complex thickness with central corneal thickness.

Results:

Endothelial/Descemet’s membrane complex thickness, central corneal thickness, and Descemet’s rejection index were all able to differentiate between clear and rejected corneal grafts (p < 0.0001, p = 0.001, and p = 0.012, respectively). Endothelial cell density and coefficient of variation did not correlate with the clinical status (p = 0.054 and p = 0.102, respectively). Endothelial/Descemet’s membrane complex thickness had the largest area under the curve using receiver operating characteristic curves (p < 0.0001). Endothelial/Descemet’s membrane complex thickness had a sensitivity of 86% and specificity of 81% with a cutoff value of >16.0 µm (p < 0.0001). The sensitivity and specificity of endothelial cell density were both 71% with a cutoff value of ⩽897 cells/mm² (p = 0.053). There was a high correlation between endothelial/Descemet’s membrane complex thickness and both Descemet’s rejection index and central corneal thickness (p < 0.0001).

Conclusion:

Endothelial/Descemet’s membrane complex thickness measured by high-definition anterior segment optical coherence tomography is a useful parameter for the diagnosis of corneal graft rejection. The diagnostic performance of endothelial/Descemet’s membrane complex thickness was significantly better than that of endothelial cell density and central corneal thickness. Endothelial cell density and the coefficient of variation were unable to diagnose corneal graft rejection in our cross-sectional study.

Factors Associated With Ocular Cyclotorsion Detected by High-Speed Dual-Detection Eye Tracker During Single-Step Transepithelial Photorefractive Keratectomy

PURPOSE

To determine demographic, surgical, and preoperative visual factors affecting the level of static and dynamic cyclotorsion (SC and DC) in eyes undergoing single-step transepithelial photorefractive keratectomy (TransPRK).

METHODS

In this cross-sectional study, 386 patients with different types of refractive errors scheduled for single-step TransPRK were enrolled. A comprehensive profile of personal, optic, and visual characteristics of patients as surgical parameters were collected. Statistical modeling was used to explore correlates of SC and DC before and during the refractive procedure, respectively.

RESULTS

There was no difference in various indices of SC and DC between right and left eyes. Lower age (beta = -0.20), uncorrected (beta = -0.99) and corrected (beta = -0.72) visual acuities, and keratometry (beta = -0.09) were significantly associated with higher ranges of DC during the laser ablation procedure. Worse mesopic contrast sensitivity (beta = 0.24) and higher (beta = 0.002, left eyes) or lower (beta = -0.002, right eyes) kappa locus also showed significant associations with a higher range of DC. In cases of SC before the procedure, amount (beta = 0.46) and axis (beta = -0.003) of the astigmatism demonstrated notable associations.

CONCLUSIONS

Through comprehensive modeling, age, visual axis indices, visual acuity, and contrast sensitivity were found to be the main factors significantly associated with dynamic ocular globe cyclotorsions during single-step TransPRK. This could help identify eyes at higher risk of cyclotorsion and its potential complications in refractive surgery. [J Refract Surg. 2018;34(11):736-744.].

Nonorganic visual loss in a child due to school bullying

Purpose

To describe a case of a child with nonorganic visual loss due to school bullying.

Observations

An eight-year-old boy presented with bilateral painless vision loss for a few days. His best corrected visual acuity (BCVA) was 20/200 in the right eye and 20/140 in the left eye. Color vision was normal. Fundoscopy, visual fields, electroretinography, electrooculography and visual evoked potentials were within normal limits. A nonorganic (psychogenic) cause of visual loss was suspected. A conversation with his parents and school teachers revealed that he was undergoing intense school bullying. Discussion between the boy and his parents and teachers' awareness helped in relieving the boy's stress. After two weeks BCVA was 20/20 bilaterally.

Conclusions and importance

School bullying is a potential cause of nonorganic vision loss in children. Correct diagnosis, and support by the parents and teachers might rapidly alleviate the symptoms.

Long-term visual outcomes after Crystalens(®) HD intraocular lens implantation

Purpose

Our purpose was to evaluate the long-term visual outcomes after bilateral implantation of Crystalens^® HD (Bausch and Lomb, Inc.) accommodative intraocular lenses.

Methods

In this study, 25 patients (50 eyes) who underwent cataract surgery and bilateral Crystalens HD accommodative intraocular lens implantation were included. The Crystalens HD lens was implanted in the bag in both eyes, without any intra- or postoperative complications. The visual parameters measured before and after surgery were: uncorrected distance visual acuity, corrected distance visual acuity (CDVA) (using the Early Diabetic Retinopathy Study [EDTRS] logMAR charts), uncorrected intermediate visual acuity, and uncorrected near visual acuity using a Birkhäuser reading chart, at a distance of 66 cm and 33 cm for intermediate and near vision, respectively, directly illuminated by a lamp of 60 watts. After surgery, the patients were evaluated at 1, 3, 6, 12, 24, and 36 months.

Results

The mean age was 68.70±7.1 (range: 54 to 83) years. The mean follow-up was 42.72±0.49 (range: 42.33 to 43.27) months. The uncorrected distance visual acuity improved from 0.56±0.41 (range: 0 to 2) preoperatively to 0.19±0.13 (range: 0 to 0.38) (logMAR scale) at the last follow-up visit, and the CDVA improved from 0.17±0.18 (range: 0 to 0.7) preoperatively to 0.05±0.05 (range: −0.02 to 0.22) at the last follow-up visit. No eyes lost lines of CDVA during the follow-up period, while 54% of patients gained one or more lines of CDVA. The uncorrected intermediate and near visual acuity was J2 or better in 71% and 69% of our patients, respectively.

Conclusion

Crystalens HD implantation seems to provide an improvement in visual acuity for far, intermediate, and near distances.

Anterior chamber angle evaluation with ultrasound biomicroscopy and optical coherence tomography in eyes implanted with a Crystalens

This study employs optical coherence tomography (OCT) and ultrasound biomicroscopy (UBM) imaging as well as optical aberrometry to examine correlations between the anterior chamber angle aperture and visual acuity for near vision as well as coma along the horizontal and vertical axes in eyes implanted with an accommodative intraocular lens (Crystalens). A retrospective comparative consecutive case series of 22 eyes of 11 patients (5 males) uneventfully implanted with a Crystalens. Eyes with signs of posterior capsular opacification were excluded. All eyes were examined with 40 MHz UBM (Ellex Eyecubed) and spectral-domain OCT (Zeiss Visante). The angle aperture along the horizontal and vertical meridians was recorded based on the software of the systems. The coma root mean square (RMS) scores for the horizontal and vertical meridians were also recorded with the iTrace aberrometer. The anterior chamber angle was significantly wider along the horizontal axis compared with the vertical axis by UBM (46.37° and 44.20°, respectively) and by OCT (46.79° and 43.58°, respectively) (p = 0.02 in both cases, paired-samples t test). The correlations between the logMAR-converted Jaeger near vision score and the horizontal or vertical angle apertures was not statistically significant. Horizontal coma RMS was significantly inversely correlated with the horizontal angle aperture (r = -0.45, p = 0.03 and r = -0.39, p = 0.04 by OCT and UBM, respectively). Measurement of the horizontal angle aperture by the modalities used may represent an anatomical and clinical predictor of the optical aberrations induced by the Crystalens.