Keratoconus Management in the Community: A Survey of Optometrists.

OBJECTIVES: Defining the patterns of practice and referral criteria of optometrists within New Zealand to investigate the diagnosis and management of keratoconus. METHODS: Optometrists recruited through the New Zealand Association of Optometrists, Cornea and Contact Lens Society of New Zealand, and private practices were invited to complete an anonymous survey. RESULTS: Responses were received from 168 optometrists (representing 20.0% of the optometrist population). Half (48%) of optometrists had ≥15 years of experience, and 22% prescribed soft contact lenses daily, whereas only 6.4% prescribed rigid gas-permeable (RGP) lenses daily. The main barriers to prescribing RGPs were experience with fitting, low market demand, and patient discomfort. When referring to an ophthalmologist, 41% reported referring on progression of corneal parameters, 27% on initial diagnosis, 21% at no set time, and 10% with a reduction in visual acuity. Most optometrists (64%) would refer for possible surgery when visual acuity dropped between 6/9 and 6/12. Optometrists with greater experience were more likely to prescribe RGP lenses and co-manage patients with ophthalmologists. Ownership of a corneal imaging unit suggested an increased likelihood of prescribing RGP lenses but did not alter referral patterns. CONCLUSION: This survey provides an overview of current practice and highlights the importance of optometrists in the diagnosis and management of keratoconus. There was a significant discrepancy in keratoconus management, regarding optical correction modality and referral criteria for ophthalmology review. Further interdisciplinary work is required between optometry and ophthalmology to standardize referral guidelines and enhance visual outcomes.

Repeatability of Scheimpflug based corneal tomography parameters in advanced keratoconus with thin corneas.

OBJECTIVE: To determine the repeatability limits of corneal tomography parameters in patients with advanced and moderately thin keratoconic corneas to assist in planning thickness-based procedural interventions. METHODS: Prospective, single-centre, repeatability study. Three tomography scans using the Pentacam AXL were obtained from patients with keratoconus with thinnest corneal thickness (TCT) ≦400 µm (sub-400 group) and compared to those with TCT = 450-500 µm (450-plus group). Eyes with previous crosslinking, intraocular surgery, or acute corneal hydrops were excluded. Eyes were age and gender-matched. The within-subject standard deviations for flat keratometry (K1), steep keratometry (K2), maximal keratometry (Kmax), astigmatism and TCT were used to calculate respective repeatability limits (r). Intra-class correlation coefficients (ICC) were also analysed. RESULTS: The sub-400 group comprised 114 eyes from 114 participants, and the 450-plus group comprised 114 eyes from 114 participants. In the sub-400 group, TCT was amongst the least repeatable parameters (33.92 µm; ICC 0.96), compared with the 450-plus group (14.32 µm; ICC 0.99, p < 0.01). In the sub-400 group, K1 and K2 of the anterior surface were the most repeatable parameters (r 3.79 and 3.22 respectively; ICC 0.97 and 0.98 respectively) compared with the 450-plus group (r 1.17 and 0.92 respectively; and ICC 0.98 and 0.99 respectively, p < 0.01). CONCLUSIONS: The repeatability of corneal tomography measurements is significantly reduced in sub-400 keratoconic corneas when compared to 450-plus corneas. Repeatability limits should be carefully considered when surgical interventions are planned for such patients.

Therapeutic non-ectasia applications of cornea cross-linking.

Corneal cross-linking is a photopolymerization technique traditionally used to strengthen corneal tissue. Corneal cross-linking utilizes riboflavin (vitamin B2) as a photosensitizer and ultraviolet-A light (UVA) to create strong covalent bonds within the corneal stroma, increasing tissue stiffness. Multiple studies have demonstrated corneal cross-linking's effectiveness in treating corneal ectasia, a progressive, degenerative, and non-inflammatory thinning disorder, as quantified by key tomographic, refractive, and visual parameters. Since its introduction two decades ago, corneal cross-linking has surpassed its original application in halting corneal ectatic disease and its application has expanded into several other areas. Corneal cross-linking also possesses antibacterial, antienzymolytic and antioedematous properties, and has since become a tool in treating microbial keratitis, correcting refractive error, preventing iatrogenic ectasia, stabilising bullous keratopathy and controlling post keratoplasty ametropia. This review provides an overview of the current evidence base for the therapeutic non-ectasia applications of cornea cross-linking and looks at future developments in the field.

Corneal Crosslinking: Present and Future.

Keratoconus is a progressive corneal thinning disorder that can lead to vision loss. In the last 2 decades, corneal crosslinking (CXL) has emerged as an effective method to halt the progression of keratoconus and reduce the number of patients requiring keratoplasty. The procedure has been adopted globally and has evolved to become a part of combination treatments to regularize the cornea and improve visual outcomes. CXL has even been extrapolated in managing other ocular pathologies such as progressive myopia, infectious keratitis, and bullous keratopathy. This review aims to summarize the current role of CXL in keratoconus and its alternative uses, and provide insights into future developments in this fast-developing field.

Thyroid eye disease in New Zealand: interaction between ethnicity and smoking status.

AIM: This study was conducted to describe the epidemiology of thyroid eye disease (TED) in New Zealand. METHODS: One hundred and sixty-one subjects with TED seen over a 14-year period in Auckland, from a combined ophthalmology-endocrinology clinic, had data extracted from clinical notes. RESULTS: Median age at onset was 47.0±15.1 years and 77.6% were female. Crude yearly incidence of TED (per 1,000,000) was 12.6 in non-smokers and 67.3 in smokers (p<0.001).  On univariate analysis, female gender, Maori ethnicity and smoking were associated with incidence of TED. On multivariate analysis, female gender and smoking status were associated with risk of TED, and the difference in ethnicity was explained by smoking status. Maori subjects with TED were more likely to be current smokers (72.7%) compared to European (39.2%), Pacific Peoples (33.3%), Asian (8.3%) and Other (12.5%). Maori ethnicity and current smokers were associated with a higher clinical activity score at presentation (p=0.049 and p=0.027). CONCLUSION: A strong association was demonstrated with female gender and smoking status and rate of TED. Maori have increased rates of TED; however, this difference was explained by smoking. Eliminating smoking would result in at least a 28.1% reduction in TED incidence in New Zealand.