Ultrasound biomicroscopy of the anterior segment in patients with primary congenital glaucoma: a review of the literature

PURPOSE

Primary congenital glaucoma (PCG) is a form of childhood glaucoma caused by maldevelopment of the anterior chamber. Disease severity differs greatly amongst patients. Ultrasound biomicroscopy (UBM) is a non-invasive technique that can visualize the anterior segment in infants in vivo. The purpose of this narrative review is to make an overview of the UBM data in PCG and study the applicability of UBM in characterizing the disease.

METHODS

An online search was performed on PubMed in December 2020. After a critical appraisal of the included articles, study and patient characteristics were summarized. The UBM measurements of the anterior segment in PCG of the different studies were analysed.

RESULTS

Six studies were included in this review. All were cross-sectional prospective studies. A total of 221 PCG eyes were examined. PCG eyes showed a larger trabecular iris angle, decreased iris thickness, narrower or absent Schlemm's canal and an increased zonular length compared to controls. Abnormal tissue membrane covering the trabecular meshwork and abnormal insertion of the iris and ciliary process were frequently found. The success rate of glaucoma surgery depended on the severity of anterior segment malformations found with UBM.

CONCLUSION

Malformations of the anterior segment in PCG can be demonstrated by UBM in vivo. This imaging can help to characterize disease severity and might support surgical treatment decisions.

Chlorhexidine for the Treatment of Fusarium Keratitis: A Case Series and Mini Review

Fungal keratitis is difficult to treat, especially Fusarium keratitis. In vitro studies show that chlorhexidine could be an interesting option as monotherapy. We describe a case series of four patients (four eyes) with Fusarium keratitis at Radboud University Medical Center (Nijmegen, the Netherlands). The patients were treated with chlorhexidine 0.02% eye drops. The in vitro activity of eight antifungals and chlorhexidine was determined according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) broth microdilution method. We also reviewed the literature on the use of chlorhexidine in the treatment of fungal keratitis. Topical chlorhexidine was well tolerated, and all patients showed complete resolution of the keratitis upon treatment with chlorhexidine. A PubMed search of the available literature was conducted (last search 8 March 2020) and yielded two randomized clinical trials (natamycin versus chlorhexidine) and one case report addressing the treatment of fungal keratitis with chlorhexidine. Chlorhexidine was found to be safe with regard to toxicity and to be superior to natamycin in the clinical trials. Chlorhexidine showed in vitro fungicidal activity against Fusarium and clinical effectiveness in our cases, supporting further clinical evaluation. Advantages of chlorhexidine are its topical application, its general availability, its low costs, its broad-spectrum activity, and its fungicidal mechanism of action at low concentrations.

Increase in treatment of retinopathy of prematurity in the Netherlands from 2010 to 2017

Purpose

Compare patients treated for Retinopathy of Prematurity (ROP) in two consecutive periods.

Methods

Retrospective inventory of anonymized neonatal and ophthalmological data of all patients treated for ROP from 2010 to 2017 in the Netherlands, subdivided in period (P)1: 1‐1‐2010 to 31‐3‐2013 and P2: 1‐4‐2013 to 31‐12‐2016. Treatment characteristics, adherence to early treatment for ROP (ETROP) criteria, outcome of treatment and changes in neonatal parameters and policy of care were compared.

Results

Overall 196 infants were included, 57 infants (113 eyes) in P1 and 139 (275 eyes) in P2, indicating a 2.1‐fold increase in ROP treatment. No differences were found in mean gestational age (GA) (25.9 ± 1.7 versus 26.0 ± 1.7 weeks, p = 0.711), mean birth weight (791 ± 311 versus 764 ± 204 grams, p = 0.967) and other neonatal risk factors for ROP. In P2, the number of premature infants born <25 weeks increased by factor 1.23 and higher oxygen saturation levels were aimed at in most centres. At treatment decision, 59.6% (P1) versus 83.5% (P2) (p = 0.263) infants were classified as Type 1 ROP (ETROP classification). Infants were treated with laser photocoagulation (98 versus 96%) and intravitreal bevacizumab (2 versus 4%). Retreatment was necessary in 10 versus 21 (p = 0.160). Retinal detachment developed in 6 versus 13 infants (p = 0.791) of which 2 versus 6 bilateral (p = 0.599).

Conclusion

In period 2, the number of infants treated according to the ETROP criteria (Type 1) increased, the number of ROP treatments, retinal detachments and retreatments doubled and the absolute number of retinal detachments increased. Neonatal data did not provide a decisive explanation, although changes in neonatal policy were reported.

Epidemiology and Clinical Management of Fusarium keratitis in the Netherlands, 2005-2016

Introduction: Recognizing fungal keratitis based on the clinical presentation is challenging. Topical therapy may be initiated with antibacterial agents and corticosteroids, thus delaying the fungal diagnosis. As a consequence, the fungal infection may progress ultimately leading to more severe infection and blindness. We noticed an increase of fungal keratitis cases in the Netherlands, especially caused by Fusarium species, which prompted us to conduct a retrospective cohort study, aiming to describe the epidemiology, clinical management, and outcome.

Materials and Methods: As fungi are commonly sent to the Dutch mycology reference laboratory for identification and in vitro susceptibility testing, the fungal culture collection was searched for Fusarium isolates from corneal scrapings, corneal swabs, and from contact lens (CL) fluid, between 2005 and 2016. All Fusarium isolates had been identified up to species level through sequencing of the ITS1-5.8S-ITS2 region of the rDNA and TEF1 gene. Antifungal susceptibility testing was performed according to the EUCAST microbroth dilution reference method. Antifungal agents tested included amphotericin B, voriconazole, and natamycin. In addition, susceptibility to the antisepticum chlorhexidine was tested. Ophthalmologists were approached to provide demographic and clinical data of patients identified through a positive culture.

Results: Between 2005 and 2016, 89 cases of Fusarium keratitis from 16 different hospitals were identified. The number of cases of Fusarium keratitis showed a significant increase over time (R² = 0.9199), with one case in the first 5 years (2005–2009) and multiple cases from 2010 and onwards. The male to female ratio was 1:3 (p = 0.014). Voriconazole was the most frequently used antifungal agent, but treatment strategies differed greatly between cases including five patients that were treated with chlorhexidine 0.02% monotherapy. Keratitis management was not successful in 27 (30%) patients, with 20 (22%) patients requiring corneal transplantation and seven (8%) requiring enucleation or evisceration. The mean visual acuity (VA) was moderately impaired with a logMAR of 0.8 (95% CI 0.6–1, Snellen equivalent 0.16) at the time of Fusarium culture. Final average VA was within the range of normal vision [logMAR 0.2 (95% CI 0.1–0.3), Snellen equivalent 0.63]. CL wear was reported in 92.9% of patients with Fusarium keratitis. The time between start of symptoms and diagnosis of fungal keratitis was significantly longer in patients with poor outcome as opposed to those with (partially) restored vision; 22 vs. 15 days, respectively (mean, p = 0.024). Enucleation/evisceration occurred in patients with delayed fungal diagnosis of more than 14 days after initial presentation of symptoms. The most frequently isolated species was F. oxysporum (24.7%) followed by F. solani sensu stricto (18%) and F. petroliphilum (9%). The lowest MICs were obtained with amphotericin B followed by natamycin, voriconazole, and chlorhexidine.

Conclusion: Although Fusarium keratitis remains a rare complication of CL wear, we found a significant increase of cases in the Netherlands. The course of infection may be severe and fungal diagnosis was often delayed. Antifungal treatment strategies varied widely and the treatment failure rate was high, requiring transplantation or even enucleation. Our study underscores the need for systematic surveillance of fungal keratitis and a consensus management protocol.

The rising incidence of Acanthamoeba keratitis: A 7-year nationwide survey and clinical assessment of risk factors and functional outcomes

Purpose

To evaluate the incidence of Acanthamoeba keratitis in the Netherlands between 2009 and 2015 and to analyse predicting factors for treatment outcome.

Methods

Patient characteristics, diagnostic methods, diagnostic delay, therapy prior to and after diagnosis, and visual outcome were obtained from medical files of all patients diagnosed with Acanthamoeba keratitis in the Netherlands between 2009 and 2015. A logistic regression analysis on treatment failure, defined as a best corrected visual acuity of less than 20/40 Snellen decimals (i.e. >0.3 logMAR or an approximate loss of three lines of visual acuity) and/or the need for keratoplasty, was performed to determine predicting factors.

Results

Two hundred and twenty-four eyes of 224 patients were included. Ninety-five percent of the patients were contact lens wearers, of whom 74% wore soft contact lenses. The number of cases increased from 16 in 2009 to 49 in 2015. This resulted in an estimated incidence of 1 in 21,000 for soft contact lens wearers in 2015. Eighty-seven eyes (39%) met the criteria for treatment failure. In a multivariable regression analysis, higher age at presentation, a higher severity stage and corticosteroid use before diagnosis were positively correlated with treatment failure. Early referral to a cornea specialist was associated with better clinical outcomes.

Conclusions

Although Acanthamoeba keratitis is still a relatively uncommon disease, the incidence in soft contact lens wearers has increased to reach 1 in 21,000 in 2015. Treatment failure occurred in 39% of cases, with age, higher severity stage, corticosteroid use before diagnosis and indirect referral to a cornea specialist as important risks factors.

[Infectious keratitis in contact lens wearers]

Infectious keratitis in contact lens wearers Infectious keratitis is a sight-threatening complication in contact lens wearers. The infection is most frequently caused by bacteria (Pseudomonas aeruginosa). However, fungi or Acanthamoeba are found in increasing frequency. Three cases illustrate a characteristic course: patient A (11-year-old male) was treated for three weeks before the characteristic aspect of Acanthamoeba keratitis was recognized and confirmed. Patient B (45-year-old female) developed a severe corneal ulcer within 4 days; microbiological diagnostics confirmed Pseudomonas aeruginosa keratitis. Examination of patient C (27-year-old female) showed an infiltrate with satellites, typical of fungal keratitis. It is important to check the use of contact lenses in patients with keratitis. Referral to the ophthalmologist is mandatory: immediate in cases with an infiltrate. A dentritiform epithelial lesion in a contact lens wearer is indicative of Acanthamoeba keratitis, whereas fungal keratitis shows satellites or feathering edges. Steroids may only be prescribed by an ophthalmologist after confirmation of the causative agent.

Successful Treatment ofFusarium Keratitis with Cornea Transplantation and Topical and Systemic Voriconazole

A case of invasive Fusarium keratitis in a previously healthy male patient was treated successfully with cornea transplantation and systemic and topical voriconazole after treatment failure with topical amphotericin B and systemic itraconazole. Topical voriconazole was well tolerated, and, in conjunction with the oral administration, it resulted in a high level of the drug in the anterior chamber of the eye (which was 160% of the plasma drug level).

Clinical and theoretical results of intraocular lens power calculation for cataract surgery after photorefractive keratectomy for myopia

OBJECTIVES

To describe the refractive results of cataract surgery after photorefractive keratectomy (PRK) for patients with myopia, and to find a more accurate method to predict intraocular lens (IOL) power in these cases.

DESIGN

Nonrandomized, retrospective clinical study.

PATIENTS AND METHODS

Nine patients (15 eyes) who underwent cataract surgery after prior PRK to correct myopia were identified. The medical records of both the laser and cataract surgery centers were reviewed.

MAIN OUTCOME MEASURES

Eight different keratometric values (K values; measured or calculated) were entered into 3 different IOL calculation formulas: SRK/T, Holladay 1, and Hoffer Q. The actual biometry and IOL parameters were used to predict postoperative refraction, which was compared with the actual refractive outcome. Also, the relative underestimation of the refractive change in corneal dioptric power by keratometry after PRK was calculated.

RESULTS

In 7 of 15 eyes, IOL exchange or piggybacking was performed because of hyperopia. Retrospectively, the most accurate K value for IOL calculation was found to be the pre-PRK K value corrected by the spectacle plane change in refraction. Use of the Hoffer Q formula would have avoided postoperative hyperopia in more cases than the other formulas. The mean underestimation of the change in corneal power after PRK varied from 42% to 74%, depending on the method of calculation.

CONCLUSION

The predictability of IOL calculation for cataract surgery after PRK can be improved by using a corrected, refraction-derived K value instead of the measured, preoperative K value.

Holmium Laser Thermal Keratoplasty for Hyperopia and Astigmatism After Photorefractive Keratectomy

PURPOSE

To report results of holmium laser thermal keratoplasty used to treat induced hyperopia and induced, as well as pre-existing astigmatism after photorefractive keratectomy.

METHODS

Sixteen eyes of 16 patients were included in this study. Contact holmium laser (Technomed Holmium 25) was used in 7 patients to correct hyperopia (8 spots at 8 or 9 mm) and in 9 patients to correct astigmatism (4 spots at 7, 8, or 9 mm). Follow-up evaluation was done after at least 6 months. The effectiveness, stability, and safety of the procedure were investigated.

RESULTS

Spherical correction was ineffective (1.00 D or less) when applied at the 9-mm diameter treatment zone. Spherical correction applied at the 8-mm diameter treatment zone was ineffective in 1 eye. Three eyes achieved 1.00 to 2.00 D change, but 2 of these eyes showed an induced astigmatic change as well. Correction of astigmatism at the 7-mm diameter treatment zone resulted in a 0 to 4.00 D cylinder component change. Treatment at the 8-mm diameter treatment zone showed a 0 to 1.50 D effect and at the 9-mm treatment zone, 0.25 to 1.50 D. All eyes that achieved significant improvement (1.00 D or more change in cylinder component) showed significant overcorrection in the first postoperative phase. There were no sight threatening complications.

CONCLUSION

Holmium laser thermal keratoplasty can be useful for the treatment of overcorrection and induced as well as pre-existing astigmatism after photorefractive keratectomy. However, predictability is low and astigmatism can be induced with the attempted spherical correction.

Photorefractive keratectomy with an ablatable mask for myopic astigmatism

PURPOSE

To evaluate efficacy, safety, and stability of photoastigmatic keratectomy (PARK) carried out with a Summit Apex Plus laser using an ablatable mask.

METHODS

Forty-one eyes of 41 patients with myopic astigmatism with follow-up of 12 months were evaluated. Treatment efficacy was compared in groups with high (>6.00 D) versus low (< or =6.00 D) preoperative spherical equivalent subjective manifest refraction, in groups with high (>2.00 D) versus low (< or =2.00 D) preoperative cylindrical component and in groups divided according to preoperative axis of cylinder.

RESULTS

At 12 months after surgery, mean spherical equivalent manifest refraction in all 41 eyes was -0.30 +/- 0.90 D. Mean cylinder component was 0.60 +/- 0.70 D. Mean reduction in astigmatic component was 67 +/- 47%. Uncorrected visual acuity of 0.5 or more was achieved in 79% of eyes; 71% of eyes achieved 0.8 or more. At 1 month after surgery, 49% of eyes had a loss of 2 or more lines of spectacle-corrected visual acuity. This loss was restored at 12 months. No statistically significant differences were found between the different subgroups.

CONCLUSION

Photoastigmatic keratectomy with ablatable mask gives satisfactory results. No relation in efficacy was found when taking into account the amount of preoperative spherical component, the cylindrical component, or the cylinder axis direction.

Treatment of hyperopia with contact Ho:YAG laser thermal keratoplasty

PURPOSE

To evaluate the effectiveness, safety, and stability of contact Ho:YAG laser thermal keratoplasty for low to moderate hyperopia.

METHODS

Fifty-five hyperopic eyes of 39 patients were treated with a Technomed contact Ho:YAG laser; 23 eyes were treated a second time. Treatment parameters were 1 octagonal ring of 8 spots with a treatment diameter of 6 mm, 7 mm, or 8 mm. Efficacy of the Ho:YAG laser treatment was evaluated after 6 months, comparing 3 treatment zone diameters. Stability and efficacy after 12 months was evaluated comparing 7-mm and 8-mm treatment zone diameters.

RESULTS

Mean reduction of spherical equivalent refraction after 6 months was not statistically significantly different between the 6-mm or 7-mm diameter zones: 1.42 (+/- 1.30) D versus 2.22 (+/- 0.44) D. An 8-mm diameter treatment zone was significantly less effective, 1.12 (+/- 0.47) D. Longer follow-up did not show stability: mean reduction of spherical equivalent manifest refraction was 1.58 (+/- 0.45) D for the 7-mm diameter treatment zone and 0.82 (+/- 0.61) D for the 8-mm diameter treatment zone after approximately 12 months. Retreatment had a limited additive effect. No clinically significant loss of spectacle-corrected visual acuity was reported. No eyes lost more than 1 line of visual acuity.

CONCLUSION

Contact Ho:YAG laser thermal keratoplasty corrected hyperopia up to 2.50 D, but predictability was poor and a regression of initial effect occurred. Instability of refraction persisted to 1 year after surgery.

Ocular hypotony after laser suture lysis following trabeculectomy with mitomycin C

BACKGROUND

To report our experience with laser suture lysis (LSL) following trabeculectomy with mitomycin C, its timing, effectiveness and related complications.

METHODS

We retrospectively examined 38 consecutive eyes of 36 patients that underwent LSL following trabeculectomy with mitomycin C.

RESULTS

The mean preLSL intraocular pressure (IOP) was 27.0 mm Hg (SD 6.3, range 16-39 mm Hg) and the postLSL IOP (IOP 1 h after the last session of LSL) was 16.0 mm Hg (SD 7.2, range 3-31 mm Hg). Following the LSL in 7 eyes (7 of 38) hypotony (IOP<6 mm Hg, lasting more than 24 h) developed. Two groups were defined. In group I no hypotony was found after LSL and group II went through a period of hypotony. The time interval between surgery and LSL was significantly shorter in group II (mean 5.7, SD 7.5, range 1-19 days), compared to group I ( mean 14.7, SD 13.0, range 1-44 days) (p=0.041). The mean final IOP (IOP measured at the last visit) was 13.3 mm Hg (SD 3.4, range 6-20 mm Hg) and mean follow-up was 6.1 months (SD 3.9, range 2.0-15.2 months). No hypotony was found at final examination. PostLSL IOP and final IOP were significantly lower in group II (p=0.002 and p=0.024 respectively). IOP reduction by LSL was significantly greater in group II (p=0.046).

CONCLUSION

LSL is an effective and safe procedure to lower the IOP following trabeculectomy with mitomycin C. Early application of LSL results in lower final IOPs, but has a higher risk of hypotony.

[Ocular infection by Pseudomonas aeruginosa in a mechanically ventilated patient]

A 59-year-old man developed bilateral keratitis several weeks after the initiation of mechanical ventilation because of respiratory failure and sepsis following abdominal surgery. Colonisation of the upper airways by P. aeruginosa had been established before. Invasion through corneal epithelial defects based on dehydration keratitis was the presumed route of infection. Despite aggressive treatment, including antibiotics, the infection was rapidly progressive in both eyes. The patient died of deterioration of his general condition. In order to prevent such eye infections in a patient on mechanical ventilation, there is a need of good eye care, prevention of corneal lesions and alertness, especially when the patient is colonised by virulent micro-organisms like P. aeruginosa.

Bilateral, anterior stromal ring opacity of the cornea

AIMS/BACKGROUND

To describe a bilateral, mid peripheral, ring-shaped corneal opacity, not resembling any known corneal degeneration, dystrophy, or other disorder, and occurring without ocular or systemic disease.

METHODS

Ophthalmic examination, haematological screening, and ultrasound biomicroscopy.

RESULTS

A 25 year old man showed grey-white, granular opacities in both corneas, with an 8 mm diameter ring configuration, and a V-shaped distribution in the anterior stroma. The surrounding corneal stroma was clear, and the tear film, the epithelium and its basement membrane, Descemet's membrane, and the endothelium were normal. Evidence of systemic disease was not found. Family members did not show corneal abnormalities.

CONCLUSION

A bilateral corneal ring opacity may occur in healthy, asymptomatic, young people. These corneal rings may result from depositions of unknown origin, or possibly a rare corneal dystrophy.

Severe keratitis due to Nocardia farcinica

Keratitis due to Nocardia farcinica occurred in a 49-year-old female after inappropriate cleaning of her semipermeable rigid contact lenses with basin-stored water during a holiday in France. N. farcinica was differentiated from Nocardia asteroides by its growth at 45 degrees C, acid production from rhamnose, its opacification of Middlebrook 7H10 agar, and its marked degree of resistance to all cephalosporins, aminoglycosides, tetracyclins, macrolides, and trimethoprim-sulfamethoxazole. To the best of our knowledge, this is the first reported case of human N. farcinica keratitis, confirming that this microorganism can be responsible for serious human disease.

[Acanthamoeba keratitis]

Three patients, women aged 69, 25 and 30 years, with refractory keratitis were found to have a rare infection with Acanthamoeba. All wore soft contact lenses. The frequency of Acanthamoeba keratitis increased in recent years. At present, an efficacious antiprotozoal therapy is available, for instance in the form of polyhexamethylene biguanide and propamidine. In cases of refractory keratitis, the possibility of an Acanthamoeba infection should be taken into account.

[Results of photorefractive keratectomy using the excimer laser in the treatment of myopia; 1-year follow-up]

OBJECTIVE

Evaluation of the first excimer laser treatments of myopia.

DESIGN

Descriptive.

SETTING

Excimer Laser Centrum, Department of Ophthalmology, University of Nijmegen, Nijmegen, the Netherlands.

METHOD

312 patients underwent spherical excimer laser treatment to correct myopia of 1.2 up to 10 diopters between February 1992 and October 1993. 245 patients completed a follow-up of one year or more; 36 retreatments were carried out. Group I (treatment 1.2 to 6 D) numbered 174 patients, group II (6.1-10 D) 71 patients.

RESULTS

After a follow-up period of one year or just before retreatment 79% of group I and 48% of group II achieved a refractive correction within 1 D of the attempted correction. Visual acuity without correction was 0.5 or more in 94% of group I and in 76% of group II. Less than one percent (n = 1) of group I and 6% (n = 4) of group II lost more than one line of best corrected visual acuity. Retreatment could correct 50% of those eyes that did not achieve a refraction within 1 D of attempted correction. Loss of visual acuity was corrected by retreatment in 5 of 6 cases of group I and in 7 of 11 cases of group II.

CONCLUSION

Based on a one-year follow-up, refractive surgery with the excimer laser appears to correct myopia between 1 and 10 D effectively. Predictability is diminishing on correcting higher amounts of refractive error. Thorough information of the patients regarding the results to be expected will prevent disappointment.

Toxic keratopathy due to the accidental use of chlorhexidine, cetrimide and cialit

Due to economical reasons some ophthalmologists are using an irrigating solution made by the hospital pharmacy instead of the commercially available solutions. These irrigating solutions come in bottles which are identical to the ones used for other solutions. During the last three years bottles were accidentally mixed up five times. Consequently, bottles containing solutions such as chlorhexidine, cetrimide, chlorhexidine/centrimide and cialit solutions were used during cataract surgery. This resulted in immediate corneal edema which, in its turn resulted in a bullous keratopathy. Four patients underwent a penetrating keratoplasty. In one patient the cornea was covered with a conjunctival flap. Light microscopy of the corneas included epithelial edema, loss of keratocytes, and a disrupted and sometimes absent endothelial cell layer.

Peters' anomaly: an unusual case

The authors report on a case of congenital bilateral protruding corneal opacities. Clinical and histological examination was consistent with a diagnosis of Peters' anomaly with a defect in the endothelium and Descemet's membrane but without abnormalities of iris and lens. Corneal grafting was performed on both eyes. During a follow-up period of one year the corneas have remained clear. However, surgical intervention for glaucoma has been necessary.

Dominant inherited tilted disc syndrome and lacquer cracks

Three patients with the tilted disc syndrome from one family were examined. The presence of the trait in three consecutive generations suggests an autosomal dominant mode of inheritance, although in these patients with variable expression. The propositus showed bilateral inferonasal retinal ectasia, with atrophic subretinal scars. Linear-like lacquer cracks, radiating from the central scars, were also present running parallel to the margin of the optic nerve head. The linear streaks were very similar to those usually seen in traumatic tears of Bruch's membrane. The mechanical stretching of the ectatic area, and its abnormal location inferonasal to the optic disc might have been responsible for the unusual pattern of the lacquer cracks in our patient.