BCLA CLEAR Presbyopia: Management with corneal techniques.

Corneal techniques for enhancing near and intermediate vision to correct presbyopia include surgical and contact lens treatment modalities. Broad approaches used independently or in combination include correcting one eye for distant and the other for near or intermediate vision, (termed monovision or mini-monovision depending on the degree of anisometropia) and/or extending the eye's depth of focus [1]. This report provides an overview of the evidence for the treatment profile, safety, and efficacy of the range of corneal techniques currently available for managing presbyopia. The visual needs and expectations of the patient, their ocular characteristics, and prior history of surgery are critical considerations for patient selection and preoperative evaluation. Contraindications to refractive surgery include unstable refraction, corneal abnormalities, inadequate corneal thickness for the proposed ablation depth, ocular and systemic co-morbidities, uncontrolled mental health issues and unrealistic patient expectations. Laser refractive options for monovision include surface/stromal ablation techniques and keratorefractive lenticule extraction. Alteration of spherical aberration and multifocal ablation profiles are the primary means for increasing ocular depth of focus, using surface and non-surface laser refractive techniques. Corneal inlays use either small aperture optics to increase depth of field or modify the anterior corneal curvature to induce corneal multifocality. Presbyopia correction by conductive keratoplasty involves application of radiofrequency energy to the mid-peripheral corneal stroma which leads to mid-peripheral corneal shrinkage, inducing central corneal steepening. Hyperopic orthokeratology lens fitting can induce spherical aberration and correct some level of presbyopia. Postoperative management, and consideration of potential complications, varies according to technique applied and the time to restore corneal stability, but a minimum of 3 months of follow-up is recommended after corneal refractive procedures. Ongoing follow-up is important in orthokeratology and longer-term follow-up may be required in the event of late complications following corneal inlay surgery.

Telephone follow-up for cataract surgery: feasibility and patient satisfaction study.

Purpose - The purpose of this paper is to investigate the feasibility of telephone follow-up (TFU) after uncomplicated cataract surgery in low-risk patients and patient satisfaction with this alternative clinical pathway. Design/methodology/approach - Prospective, non-randomised cohort study. A ten-point subjective ophthalmic assessment questionnaire and a six-point patient satisfaction questionnaire were administered to patients following routine cataract surgery at two to three weeks post-procedure. All patients were offered a further clinic review if required. Exclusion criteria comprised ophthalmic co-morbidities, hearing/language impairment and high risk of post-operative complications. Patient notes were retrospectively reviewed over the study period to ensure no additional emergency attendances took place. Findings - Over three months, 50 eyes of 50 patients (mean age: 80; age range 60-91; 66 per cent second eye surgery) underwent uncomplicated phacoemulsification surgery received a TFU at 12-24 days (mean: 16 days) post-operatively. Subjective visual acuity was graded as good by 92 per cent of patients; 72 per cent patients reported no pain and 20 per cent reported mild occasional grittiness. Patient satisfaction was graded 8.9 out of 10; 81.6 per cent defined TFU as convenient and 75.5 per cent of patients preferred TFU to routine outpatient review. No additional visits were required. Research limitations/implications - Non-randomised with no control group; small sample size. One patient was unable to be contacted. Practical implications - Post-operative TFU can be suitably targeted to low-risk patients following uncomplicated cataract surgery. This study demonstrated a high patient satisfaction. A larger, randomised study is in progress to assess this further. Originality/value - This is the first study reporting TFU results and patient satisfaction to the usual alternative two-week outpatient review.

In vivo optical coherence tomography (OCT) in periocular basal cell carcinoma: correlations between in vivo OCT images and postoperative histology.

AIM: To investigate in vivo optical coherence tomography (OCT) for imaging of periocular basal cell carcinoma (BCC). METHODS: Consecutive patients with periocular BCC were prospectively investigated with VivoSight OCT imaging prior to surgical excision. Histology sections were compared with OCT images with regard to lesion measurements (x, y and z dimensions) and histological features. RESULTS: A total of 15 patients with biopsy proven BCC were recruited. The OCT horizontal margins correlated positively with histology (r=0.8 and 0.66, x and y axes) and could be identified in 3/15 (x axis) and 6/15 (y axis) cases. The vertical margin correlation was r=0.43 and BCC depth could be measured in 9/15 cases. The following histological features of BCC could be identified on OCT images: (1) lobular pattern (100%); (2) dilated blood vessels (80%); (3) reflective margins of tumour lobules (100%); and (4) epidermal thinning overlying BCC lobules (100%). CONCLUSIONS: This study indicated a strong positive correlation between the margins of periocular BCCs measured using in vivo OCT and histology, and a weak positive correlation with depth of invasion. VivoSight OCT produced high resolution images of BCC morphology. The limitations in horizontal margin measurements could potentially be overcome by design modification of the scanning probe.

Retina rejuvenation therapy for diabetic macular edema: a pilot study.

PURPOSE: To prospectively investigate the safety and efficacy of a novel frequency-doubled nanosecond-pulsed laser with discontinuous beam energy distribution (2RT, Ellex) for the treatment of diabetic macular edema. METHODS: Twenty-three consecutive patients (38 eyes) with newly diagnosed diabetic macular edema were recruited and assessed with logarithm of the minimum angle of resolution best-corrected visual acuity, central macular thickness measured with optical coherence tomography (OCT/scanning laser ophthalmoscope, OPKO/OTI), microperimetry, fundus photography, and fundus fluorescein angiography. Macular grid treatments were performed with 2RT laser system by 1 operator. Patients were examined with logarithm of the minimum angle of resolution best-corrected visual acuity, central macular thickness, microperimetry, and fundus photography at 3 weeks and 6 weeks and 3 months and 6 months. Fundus fluorescein angiography was repeated at 3 months and 6 months. RESULTS: Six months postoperatively, 17 patients (28 eyes) completed the study. No complications were identified after 2RT therapy. Intraoperative retinal discoloration was observed in 2 cases, fully resolved at 3 months with no permanent anatomical or functional changes. Mean logarithm of the minimum angle of resolution visual acuity improved from 20/44 at baseline to 20/27 at 6 months. The change in best-corrected visual acuity was significant (P = 0.0190). Central macular thickness in the central 1-mm subfield, retinal exudates and vascular leakage decreased in the majority of patients at 6 months (46, 41, and 55%, respectively), although the change from baseline was not statistically significant. Microperimetry confirmed photoreceptor integrity and showed a trend of improvement that correlated with decreased central macular thickness. CONCLUSION: For the first time, we achieved a beneficial effect on diabetic macular edema without the side effects of conventional laser therapy. The efficacy of this system in comparison with standard argon laser photocoagulation and in the treatment of other conditions affecting the retinal pigment epithelium needs further investigation.

Optical coherence tomography may be used to predict visual acuity in patients with macular edema.

PURPOSE: To determine whether the volume of retinal tissue passing between the inner and outer retina in macular edema could be used as an indicator of visual acuity. METHODS: Diabetic and uveitic patients with cystoid macular edema (81 subjects, 129 eyes) were recruited. Best corrected logMAR visual acuity and spectral optical coherence tomography (OCT/SLO; OTI, Toronto, ONT, Canada) were performed in all patients. Coronal OCT scans obtained from a cross section of the retina between the plexiform layers were analyzed with a grid of five concentric radii (500, 1000, 1500, 2000, and 2500 µm centered on the fovea). The images were analyzed to determine the amount of retinal tissue present within each ring. A linear regression model was developed to determine the relationship between tissue integrity and logMAR visual acuity. RESULTS: A linear relationship between tissue integrity and VA was demonstrated. The volume of retinal tissue between the plexiform layers in rings 1 and 2 (up to 1000 µm from the foveal center) predicted 80% of visual acuity. By contrast, central macular thickness within the central 1000 µm predicted only 14% of visual acuity. CONCLUSIONS: This study showed that the cross-sectional area of retinal tissue between the plexiform layers in cystoid macular edema, as imaged by OCT, is the best indicator of visual function at baseline. Further prospective treatment trials are needed to investigate this parameter as a predictor of visual outcome after intervention.

Further insight into West African crystalline maculopathy.

OBJECTIVE: To describe new features and ocular coherence tomographic scans of individuals with West African crystalline maculopathy (WACM). DESIGN: Prospective observational case series. PARTICIPANTS: All 14 patients with WACM identified in the medical retina clinic during a 6-month period. METHODS: Full ophthalmic examination and high-resolution ocular coherence tomographic imaging and fluorescein angiography where indicated. MAIN OUTCOME MEASURES: Ethnicity and dietary history of individuals, location of crystals, and associated retinal comorbidity. RESULTS: Patients originated from several West African countries. Two patients had unilateral WACM. The crystals were yellow-green in color, birefringent, and located in the layer of Henle of the fovea. Coexistent retinal pathology was present in all patients. CONCLUSIONS: Several new features of the condition are described. Breakdown of the blood retinal barrier may play a role in the formation of the crystals.

Antibacterial activity of preservative-free topical anesthetic drops in current use in ophthalmology departments.

AIM: The antibacterial effect of topical anesthetics may lead to false-negative cultures from corneal specimens of bacterial keratitis. This in vitro study compared the antibacterial effect of 3 unpreserved topical anesthetics to indicate the most appropriate agent for corneal scrapes. METHODS: Four bacterial strains (Staphylococcus epidermidis, Staphylococcus aureus, Pseudomonas aeruginosa, and Streptococcus pneumoniae) derived from the most frequently isolated microorganisms from corneal ulcers were cultured from stored control stocks and clinical specimens. These strains were used to determine the minimum inhibitory concentration (MIC) of 3 preservative-free anesthetic eyedrops: proxymetacaine 0.5%, oxybuprocaine 0.4%, and tetracaine 1%. RESULTS: There was no inhibition of growth seen with proxymetacaine 0.5% (5000 microg/mL) with any of the organisms except S. epidermidis, which demonstrated an MIC of 2500 microg/mL (equivalent to a dilution of (1/2)). Tetracaine 1% (10,000 microg/mL) produced an MIC ranging between 625 and 1250 microg/mL, inhibiting all 4 strains at the commercially available dilution. Oxybuprocaine 0.4% (4000 microg/mL) resulted to be the second most inhibitory preparation with an MIC ranging between 1000 and 2000 microg/mL. CONCLUSIONS: Currently used preservative-free topical anesthetics differ in bacterial growth inhibition. This in vitro study showed that proxymetacaine 0.5% is the least inhibitory on bacterial growth and therefore the most appropriate to be used before corneal scrapes.

A large deletion in the adRP gene PRPF31: evidence that haploinsufficiency is the cause of disease.

PURPOSE: To report a large deletion that encompasses more than 90% of PRPF31 gene and two other neighboring genes in their entirety in an adRP pedigree that appears to show only the typical clinical features of retinitis pigmentosa. METHODS: To identify PRPF31 mutation in a dominant RP family (ADRP2) previously linked to the RP11 locus, the 14 exons of PRPF31 were screened for mutations by direct sequencing. To investigate the possibility of a large deletion, microsatellite markers near PRPF31 gene were analyzed by non-denaturing PAGE. RESULTS: Initial screening of PRPF31 gene in the ADRP2 family did not reveal an obvious mutation. A large deletion was however suspected due to lack of heterozygosity for nearly all PRPF31 intragenic single nucleotide polymorphysm (SNPs). In order to estimate the size of the deletion, SNPs and microsatellite markers spanning and flanking PRPF31 were analyzed in the entire ADRP2 family. Haplotype analysis with the above markers suggested a deletion of approximately 30 kb that included the putative promoter region of a novel gene OSCAR, the entire genomic content of genes NDUFA3, TFPT and more than 90% of PRPF31 gene. Sequence analysis of the region flanking the potential deletion showed a high presence of Alu elements implicating Alu mediated recombination as the mechanism responsible for this event. CONCLUSIONS: This mutation provides evidence that haploinsufficiency rather than aberrant function of mutated proteins is the cause of disease in these adRP patients with mutations in PRPF31 gene.

Expression of PRPF31 mRNA in patients with autosomal dominant retinitis pigmentosa: a molecular clue for incomplete penetrance?

PURPOSE: To investigate whether the incomplete penetrance phenotype characteristic of adRP families linked to chromosome 19q13.4 (RP11) with mutations in the PRPF31 gene is due to differentially expressed wild-type alleles in symptomatic and asymptomatic individuals. METHODS: Real-time quantitative RT-PCR was performed on RNA from lymphoblastoid cell lines derived from a large adRP family (RP856/AD5) that segregates an 11bp deletion in exon 11 of PRPF31. The mRNA levels from only the wild-type allele of PRPF31 were assayed using a probe designed across the deletion. The Mann-Whitney U test was used to compare the median mRNA copy numbers of the symptomatic with the asymptomatic carriers of the mutant PRPF31 allele. The PRPF31 protein levels from symptomatic and asymptomatic individuals were also assayed by Western blot analysis using an antibody specific to the wild-type PRPF31 protein. RESULTS: The use of cell lines was validated by the observation that cell transformation did not alter PRPF31 expression in the cell lines compared with nucleated blood cells and donor retinas. A significant difference in wild-type PRPF31 mRNA levels was observed between symptomatic and asymptomatic individuals (P < 0.001) and was supported by Western blot analysis of the PRPF31 protein. CONCLUSIONS: Partial penetrance in RP11 could be due to the coinheritance of a PRPF31 gene defect and a low-expressed wild-type allele. This study revealed a potential avenue for future therapy in that it appears the moderate overexpression of wild-type PRPF31 may prevent clinical manifestation of the disease.