Elsie Chan

A randomised, prospective study to investigate the efficacy of riboflavin/ultraviolet A (370 nm) corneal collagen cross-linkage to halt the progression of keratoconus

Aims A blind, randomised, prospective, bilateral study to investigate the efficacy of riboflavin/ultraviolet A corneal collagen cross-linkage to halt the progression of keratoconus. Methods 24 patients with early/moderate bilateral keratoconus with recent progression were recruited. One eye was randomly assigned to undergo collagen cross-linkage following epithelial removal with riboflavin 0.1% and ultraviolet A (370 nm at 3 mW/cm2). The other remained untreated as a control. The follow-up was 18 months in 22 patients. Results At 18 months, Orbscan II 3 mm, 5 mm keratometry and simulated astigmatism and cone apex power and wave-front measurements (Keraton Scout), including root mean square, coma and pentafoil showed significant reductions from baseline in treated compared with untreated eyes (p=0.04). In treated eyes at 18 months, the best spectacle-corrected acuity improved (p=0.01), and Orbscan II-simulated keratometry (p<0.001), 3 mm keratometry (p=0.008), simulated astigmatism (p=0.007), cone apex power (p=0.002), root mean square, coma, spherical aberration, secondary astigmatism and pentafoil (p=0.05) decreased from baseline. One treated eye experienced transient recurrent corneal erosions; otherwise there were no complications attributable to the treatment. Conclusions Corneal collagen cross-linkage appears to be an effective and safe modality to halt the progression of keratoconus. Improvements in visual and topographic parameters are seen in some eyes.

Complications of cataract surgery

Modern cataract surgery is safe in more than 95 per cent of patients. In the small number of cases where a serious complication occurs, the most common is an intra-operative posterior capsular rupture. This can lead to vitreous loss or a dropped nucleus and can increase the risk of post-operative cystoid macular oedema or retinal detachment. Post-operatively, posterior capsular opacification is the most common complication and can be readily treated with a YAG capsulotomy. The most devastating complication is endophthalmitis, the rate of which is now significantly decreased through the use of intracameral antibiotics. As a clinician, the most important step is to assess the patient pre-operatively to predict higher risk individuals and to counsel them appropriately. In these patients, various pre- or intra-operative management steps can be taken in addition to routine phacoemulsification to optimise their visual outcome.Modern cataract surgery is safe in more than 95 per cent of patients. In the small number of cases where a serious complication occurs, the most common is an intra‐operative posterior capsular rupture. This can lead to vitreous loss or a dropped nucleus and can increase the risk of post‐operative cystoid macular oedema or retinal detachment. Post‐operatively, posterior capsular opacification is the most common complication and can be readily treated with a YAG capsulotomy. The most devastating complication is endophthalmitis, the rate of which is now significantly decreased through the use of intracameral antibiotics. As a clinician, the most important step is to assess the patient pre‐operatively to predict higher risk individuals and to counsel them appropriately. In these patients, various pre‐ or intra‐operative management steps can be taken in addition to routine phacoemulsification to optimise their visual outcome.

Current status of corneal collagen cross‐linking for keratoconus: a review

Over the past decade, corneal collagen cross-linking has become commonplace as a treatment option for individuals with progressive keratoconus. This is based on laboratory data suggesting that cross-linking using riboflavin and ultraviolet-A irradiation increases collagen diameter and the biomechanical strength of the treated cornea. Case series and limited randomised controlled trials support these findings with data demonstrating that cross-linking slows and possibly halts the progression of keratoconus. In some patients cross-linking results in an improvement in maximum corneal curvature, visual acuity, spherical equivalent and higher-order aberrations. The number of reported complications is small. More recently, variations in the treatment protocol have been described, although they have not yet been subject to comparative studies. While the published data indicate cross-linking is effective in modifying the natural history of keratoconus, the long-term impact of this treatment is still unknown. This paper reviews the theoretical basis, pre-clinical research and clinical results of corneal collagen cross-linking in keratoconus.Over the past decade, corneal collagen cross‐linking has become commonplace as a treatment option for individuals with progressive keratoconus. This is based on laboratory data suggesting that cross‐linking using riboflavin and ultraviolet‐A irradiation increases collagen diameter and the biomechanical strength of the treated cornea. Case series and limited randomised controlled trials support these findings with data demonstrating that cross‐linking slows and possibly halts the progression of keratoconus. In some patients cross‐linking results in an improvement in maximum corneal curvature, visual acuity, spherical equivalent and higher‐order aberrations. The number of reported complications is small. More recently, variations in the treatment protocol have been described, although they have not yet been subject to comparative studies. While the published data indicate cross‐linking is effective in modifying the natural history of keratoconus, the long‐term impact of this treatment is still unknown. This paper reviews the theoretical basis, pre‐clinical research and clinical results of corneal collagen cross‐linking in keratoconus.

Long-term Outcomes of Deep Anterior Lamellar Keratoplasty Versus Penetrating Keratoplasty in Australian Keratoconus Patients

Purpose: The aim of this study is to compare long-term visual and surgical outcomes after performing deep anterior lamellar keratoplasty (DALK) and penetrating keratoplasty (PK) for keratoconus. Methods: This is a retrospective review of 73 consecutive patients with keratoconus, managed with DALK or PK, between 2000 and 2010, by a single surgeon. Data were collected on baseline parameters, best-corrected visual acuity (BCVA) in logarithm of the mean angle of resolution (logMAR), subjective refraction, graft survival, and complications. Results: Thirty-one (42.5%) eyes underwent a DALK, and 42 (57.5%) eyes underwent a PK. All PK-operated and 29 out of 31 (93.5%) DALK-operated eyes remained clear at the last review. Postoperative complications were significantly more frequent after PK (57.1%) than after DALK (26.5%; P = 0.0197). The mean BCVA was not significantly different for DALK (0.14 logMAR, SD 0.2) versus PK (0.05 logMAR, SD 0.11); however, eyes that underwent PK were more likely to achieve a BCVA of 0.0 logMAR (P = 0.0029). Subjective refraction and method of visual correction (spectacles or contact lenses) were similar for each group. Conclusions: DALK-operated patients in this study showed similar graft survival, fewer postoperative complications, and equivalent refractive outcomes. No significant difference in the mean BCVA was noted between DALK and PK cases.

Trypan blue dye for anterior segment surgeries

Use of vital dyes in ophthalmic surgery has gained increased importance in the past few years. Trypan blue (TB) has been a popular choice among anterior segment surgeons mainly due to its safety, ease of availability, and remarkable ability to enable an easy surgery in difficult situations mostly related to visibility of the targeted tissue. It is being used in cataract surgery since nearly a decade and its utilization has been extended to other anterior segment surgeries like trabeculectomy and corneal transplantation. This review will discuss the techniques and outcome of TB dye-assisted anterior segment surgeries.

Treatment of infectious keratitis with riboflavin and ultraviolet-A irradiation

UNLABELLED We report 4 eyes with infectious keratitis treated with riboflavin/ultraviolet-A irradiation (corneal collagen crosslinking [CXL]) in addition to medical treatment. In 2 eyes with bilateral keratitis, the fellow eye was treated with medical treatment alone. The other 2 eyes had refractory keratitis. The results suggest that CXL may be more worthwhile in cases refractory to conventional medical treatment. FINANCIAL DISCLOSURE No author has a financial or proprietary interest in any material or method mentioned.

A randomised controlled trial of alcohol delamination and phototherapeutic keratectomy for the treatment of recurrent corneal erosion syndrome

Aim To compare the efficacy of alcohol delamination (ALD) and phototherapeutic keratectomy (PTK) for the treatment of recurrent corneal erosion syndrome (RCES) in a prospective, randomised, controlled trial. Methods Patients with RCES not responding to conservative treatment were recruited and randomised to undergo ALD or PTK. Patients were masked to their treatment group. The primary outcome measure was the intensity of pain on waking, using a numerical rating scale between 0 and 10 to record a subjective pain score. Results 17 eyes were treated with ALD and 16 eyes were treated with PTK. The mean follow-up period was 16.25 and 17.25 months, respectively. There were no differences in baseline parameters or pain scores at 3, 6, 12 and 24 months between the groups. The pain score improved from baseline at 3 months (ALD, p=0.022; PTK, p=0.014) and 6 months (ALD, p=0.033; PTK, p=0.036) in both groups, but only in the ALD group at 24 months (ALD, p=0.035; PTK, p=0.500). Overall, there was complete or partial resolution of symptoms in 11 (65%) eyes in the ALD group and 10 (63%) eyes in the PTK group. Recurrence of symptoms was observed in five eyes in the ALD group and six eyes in the PTK group. There was one treatment failure in the ALD group. There were no long-term complications. Conclusions ALD should be considered as an alternative treatment for the management of RCES with promising results compared with PTK.

Nature and incidence of severe limbal stem cell deficiency in Australia and New Zealand

This study aimed to determine the nature and incidence of severe limbal stem cell deficiency (LSCD) in Australia and New Zealand.

Assessment of anterior segment parameters of keratoconus eyes in an Australian population.

Purpose To assess anterior segment parameters of eyes with keratoconus (KC) at different clinical stages of disease. Methods KC and non-KC patients were recruited from public and private clinics in Melbourne, Australia. Axial length (AL), mean front corneal curvature (Front Km), mean back corneal curvature (Back Km), central corneal thickness (CCT), corneal thickness at the apex (CTA), corneal thickness at the thinnest point (CTT), anterior chamber depth (ACD), and corneal volume were noted for all the eyes. Results A total of 181 individuals comprising 44 (24.3%) subclinical KC, 118 (65.2%) clinical KC, and 19 (10.5%) control subjects were analyzed. Significant differences were noticed between the subclinical KC and control group for ACD and CTT, whereas between clinical and control groups, significant differences were obtained for AL, CCT, CTA, CTT, and ACD (p < 0.05). In the case of mild, moderate, and severe KC groups, Back Km, CCT, CTA, and CTT were significantly associated (p < 0.001) with increasing disease severity. We further did receiver operating characteristic analysis to confirm the importance of pachymetric parameters in differentiating between control and KC eyes. The area under the receiver operating characteristic curve value of CTT for subclinical and clinical KC was 0.68 and 0.82, which showed that it may be a potential marker for the early detection and prevention of KC. Conclusions This study identified the anterior chamber parameters that differ between subclinical and clinical KC as well as the severity of KC. There is a significant reduction in CTT between control and subclinical eyes, although there are no significant alterations in Front and Back Km or AL between the two groups. Also, a progressive reduction in the pachymetric readings at the pupil center, apex, and thinnest corneal point was identified when comparing mild to severe KC groups. Thus, corneal thickness represents an important parameter that needs to be considered in monitoring KC disease severity.

A retrospective study of the indications and outcomes of capsular tension ring insertion during cataract surgery at a tertiary teaching hospital

Background The purpose was to determine preoperative indications, intraoperative procedures, and outcomes of capsular tension ring (CTR) insertion during cataract surgery. Methods A review of all patients undergoing cataract surgery with insertion of a CTR between July 2000 and June 2010 was conducted at The Royal Victorian Eye and Ear Hospital, a large tertiary teaching hospital in Victoria, Australia. Information relating to each patient’s demographic details, preoperative assessment, surgical procedure, and postoperative assessment were obtained. Results Eighty-four eyes of 82 patients were included in this study. The main indications for CTR insertion were previous trauma, pseudoexfoliation syndrome, and mature cataracts. Twenty-one eyes (25.0%) did not have any obvious preoperative indication. A posterior capsule tear was the most common intraoperative complication (3.6%). An intraocular lens was successfully implanted in the bag in 72 eyes (85.7%). Postoperatively, the most common complications were a decentered intraocular lens (8.3%) and persistent corneal edema (6.0%). Overall, 61 eyes (72.6%) had better postoperative visual acuity compared with preoperative acuity, with 67 patients (79.8%) achieving vision of 20/40 or better. Conclusion For the majority of cases, CTR use in complex cataract surgeries is associated with improved postoperative outcomes. CTR implantation is most commonly required in patients with known risk factors for zonular instability.