Assessment of Health Disparities and Barriers to Accessing Keratoconus and Crosslinking at a Tertiary Referral Center

PURPOSE

The aim of this study was to determine the barriers to accessing the crosslinking service in Auckland, New Zealand.

METHODS

This was a prospective 1-year study of patients at Auckland District Health Board. Studied parameters included age, sex, body mass index, ethnicity, New Zealand Deprivation (NZDep; an area-based measure of socioeconomic status, 1 = low deprivation-10 = high deprivation) score of residence, disease severity (maximum keratometry and thinnest corneal thickness), attendance, distance travelled, car ownership, employment status, and visual outcomes. Statistical analysis was performed using independent t tests, Pearson correlation, independent samples ANOVA, MANCOVA, and binomial logistic regression.

RESULTS

Four hundred fifty-four patients with keratoconus were analyzed and had a mean age of 24.1 ± 0.8 years, mean body mass index of 33.0 ± 9.7 kg/m 2 , and 43% were female. Pacific Peoples consisted 40.2% of the population; Māori 27.2%; Europeans 21.2%; Asian 9.9%; and Middle Eastern, Latin American, and African (MELAA) 1.3%. The mean distance travelled was 12.5 ± 9.5 km, NZDep score was 6.8 ± 2.6, and attendance was 69.0 ± 42.5%. The lowest attendance was observed in Pacific Peoples (58.9%) and the highest was in Asians (90%) ( P = 0.019). The mean worst-eye visual acuity at attendance was 0.75 ± 0.47 logMAR (6/35). Unemployment was associated with worse best-eye visual acuity at FSA ( P = 0.01) and follow-up ( P < 0.05). Māori and Pacific Peoples had the highest NZDep ( P < 0.001), were younger at presentation ( P = 0.019), had higher disease severity ( P < 0.001), and worse visual acuity ( P < 0.001).

CONCLUSIONS

Poor attendance was seen in this cohort. Pacific Peoples and Māori presented younger with worse disease severity and visual acuity but also had the highest nonattendance. These results suggest that deprivation, factors associated with ethnicity, and unemployment are potential barriers to attendance.

Comparison of 110- and 145-µm Small-Incision Lenticule Extraction Cap Thickness: A Randomized Contralateral Eye Study

PURPOSE

To investigate the visual, refractive, and biomechanical outcomes of small incision lenticule extraction (SMILE) with two different cap thicknesses.

METHODS

Thirty-four patients were included in this prospective, randomized, contralateral eye study. Subjects were randomized to receive SMILE surgery with a 110-m cap thickness in one eye and 145-µm cap thickness in the fellow eye. Uncorrected and corrected distance visual acuity, contrast sensitivity (CS), total higherorder aberrations (THOAs) and corneal biomechanical properties were compared 3 months after surgery.

RESULTS

Postoperative refractive and visual outcomes, CS and THOAs were similar between the two groups ( P > 0.05 for all parameters). At 3 months postoperatively, there was a significant difference in Corvis ST Biomechanical Index (CBI); stiffness parameter at first applanation (SP A1), and Integrated Radius between the two groups (all P < 0.05).

CONCLUSIONS

Eyes with thicker SMILE corneal caps showed no advantage regarding visual acuity, CS and THOAs over eyes with thinner caps. However, higher cap thickness may result in better corneal biomechanical properties postoperatively.

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.

Comparing Repeatability and Agreement between Commonly Used Corneal Imaging Devices in Keratoconus

SIGNIFICANCE

Keratometry and pachymetry are important for diagnosis and monitoring of keratoconus. Many corneal imaging units exist, but comparison to determine repeatability and agreement is paramount for adequate keratoconus management in primary and secondary care.

PURPOSE

This study aimed to evaluate the repeatability and agreement of a Placido disc-based videokeratoscope (Melbourne, Victoria, Australia) used in primary care with spectral-domain optical coherence tomography (Optopol Technology, Zawiercie, Poland) and Scheimpflug corneal tomography (Oculus, Wetzlar, Germany) in secondary care.

METHODS

This was a prospective single-center study where one eye was randomized to have central corneal thickness;thinnest corneal thickness (TCT); and maximum, mean, steep, and flat keratometry (Kmax, Kmean, Ksteep, and Kflat, respectively), measured with all three devices. Three measurements were completed per device to assess intraobserver repeatability.

RESULTS

A total of 110 eyes from 110 patients with keratoconus were analyzed. Repeatability was best with the Pentacam for central corneal thickness, Kmax, Kmean, Ksteep, and Kflat parameters (precision, 9.21, 0.8, 0.38, 0.52, and 0.58). The Medmont had better repeatability than the Revo with Kmax, Kmean, Ksteep, and Kflat (precision, 1.41,1.35,1.43, and 1.59). Revo had the best repeatability with TCT (precision, 3.81). The intraclass correlation coefficient was >0.94 for all parameters in all devices. Agreement was generally poor between devices. However, there was good agreement between Pentacam and Medmont Kflat measurements ( P > .05).

CONCLUSIONS

Repeatability of keratometry parameters with the Pentacam and Medmont was greater than the Revo, suggesting a lower threshold for detecting change in anterior corneal parameters. The Revo had the greatest repeatability for TCT, suggesting a lower threshold for detecting thinning in disease progression and corneal-crosslinking safety. There was poor agreement between devices, and it is not recommended for them to be used interchangably.

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.

Ocular Antibiotic Utilisation across Aotearoa/New Zealand

Ocular antibiotics are integral to the prevention and treatment of bacterial ocular infections. This study aimed to describe their utilisation across New Zealand according to patient and healthcare factors. Every subsidy-eligible community dispensing of ocular chloramphenicol, fusidic acid and ciprofloxacin in New Zealand, between 2010 and 2019, was included in this analysis. Number of dispensings/1000 population/year was quantified, stratified by patient age and urban/non-urban health districts. Dispensing rates by ethnicity were determined and were age adjusted. The proportion of dispensings by socioeconomic deprivation quintile was also determined. Chloramphenicol was the most commonly dispensed antibiotic; however, its utilisation decreased over time. Ciprofloxacin use was higher in children, while chloramphenicol use was higher in older patients. Ciprofloxacin usage was higher among Māori and Pasifika ethnicities, while fusidic acid use was lower. Chloramphenicol usage was higher among Pasifika. Antibiotic utilisation was higher in urban health districts, and in the most deprived quintile; both were most marked with ciprofloxacin. The utilisation of publicly funded ocular antibiotics across New Zealand varied between patient subgroups. These findings will help improve the prevention, management and outcomes of bacterial ocular infections, and support wider initiatives in antibiotic stewardship and medicine access equity.

Agreement between a Spectral-Domain Ocular Coherence Tomography Biometer with a Swept-Source Ocular Coherence Tomography Biometer and an Optical Low-Coherence Reflectometry Biometer in Eyes with Cataract

Purpose

To assess the agreement between biometric parameters measured by a spectral-domain optical coherence tomography optical biometer device (Optopol Revo NX) with a validated swept-source biometer (IOLMaster 700) and a validated optical low-coherence reflectometry biometer (Lenstar LS 900), in cataract surgery candidates.

Methods

In this prospective comparative study, 100 patients (100 eyes) who were eligible for cataract surgery were involved. Bland-Altman plots were used to assess agreement between devices for biometric parameters including axial length (AL), anterior chamber depth (ACD), lens thickness (LT), and central corneal thickness (CCT).

Results

AL measurements were successful in 82 eyes (82.0%) with Revo NX, in 91 eyes (91.0%) with Lenstar LS 900, and in 97 eyes (97.0%) with IOLMaster 700. When Revo NX was compared to IOL Master 700 and Lenstar LS 900, the mean differences were as follows: -0.02 ± 0.02 mm and -0.02 ± 0.03 mm (P = 0.313, P = 0.525) for AL, 0.01 ± 0.03 mm and 0.10 ± 0.03 mm (P = 0.691, P = 0.002) for ACD, -0.15 ± 0.03 mm and 0.001 ± 0.04 mm (P < 0.001, P = 0.95) for LT, and -2.29 ± 0.92 μm, and 0.73 ± 1.43 μm (P = 0.015, P = 0.612) for CCT. Three devices were highly correlated for AL, ACD, LT, and CCT (interclass correlation coefficient > 0.75). Bland-Altman plots showed a narrower 95% limit of agreement (-0.35 to 0.31) between Revo NX and IOLMaster 700 in measuring AL.

Conclusions

Despite the higher measurement failure rate in eyes with cataract, the Revo NX showed very good agreement with the IOLMaster 700 and Lenstar LS 900 optical biometers in measuring AL, ACD, LT, and CCT. However, ACD and LT measurements cannot be considered interchangeable between these devices.

The Vision Correction Questionnaire: an electronic patient-reported outcome measure for refractive surgery

PURPOSE

To develop a psychometrically robust electronic patient reported outcome measure (ePROM) for refractive surgery.

SETTING

Moorfields Eye Hospital, London, United Kingdom.

DESIGN

Questionnaire development study.

METHODS

Items were derived in 6 domains (spectacle dependence, visual quality, eye comfort, functional freedom, emotional wellbeing, and satisfaction with treatment) from existing Rasch adjusted instruments, patient and surgeon feedback, and refinement in semistructured interviews before administration to a field test cohort (n = 360) of patients undergoing routine refractive surgery. Spectacle dependence and satisfaction with treatment items were used to provide descriptive statistical information only. Contemporary criteria for item reduction and Rasch modeling were applied to the remaining domains. The finalized questionnaire was then administered to a second patient cohort (n = 120) before and after surgery to assess sensitivity to change.

RESULTS

A 5-item scale derived for emotional wellbeing was unidimensional and a good fit to the Rasch model with ordered category response profiles, adequate precision (person separation 2.22 logits, reliability coefficient 0.83), and no misfitting items. Mean logit scores were 0.91 higher after treatment (effect size 1.26) suggesting a positive impact on emotional wellbeing. Functional scales could not be derived for visual quality, eye comfort, or functional freedom. Single-item ratings for visual quality and eye comfort were retained in our final 11-item questionnaire.

CONCLUSIONS

This short ePROM should integrate well with routine clinical care and clinical trials in refractive surgery. The Rasch adjusted emotional wellbeing scale may help quantify the way patients feel about refractive surgery, with the remaining items providing useful descriptive information.

Toward Universal Eye Health Coverage-Key Outcomes of the World Health Organization Package of Eye Care Interventions: A Systematic Review

Importance

Despite persistent inequalities in access to eye care services globally, guidance on a set of recommended, evidence-based eye care interventions to support country health care planning has not been available. To overcome this barrier, the World Health Organization (WHO) Package of Eye Care Interventions (PECI) has been developed.

Objective

To describe the key outcomes of the PECI development.

Evidence Review

A standardized stepwise approach that included the following stages: (1) selection of priority eye conditions by an expert panel after reviewing epidemiological evidence and health facility data; (2) identification of interventions and related evidence for the selected eye conditions from a systematic review of clinical practice guidelines (CPGs); stage 2 included a systematic literature search, screening of title and abstracts (excluding articles that were not relevant CPGs), full-text review to assess disclosure of conflicts of interest and affiliations, quality appraisal, and data extraction; (3) expert review of the evidence extracted in stage 2, identification of missed interventions, and agreement on the inclusion of essential interventions suitable for implementation in low- and middle-income resource settings; and (4) peer review.

Findings

Fifteen priority eye conditions were chosen. The literature search identified 3601 articles. Of these, 469 passed title and abstract screening, 151 passed full-text screening, 98 passed quality appraisal, and 87 were selected for data extraction. Little evidence (≤1 CPG identified) was available for pterygium, keratoconus, congenital eyelid disorders, vision rehabilitation, myopic macular degeneration, ptosis, entropion, and ectropion. In stage 3, domain-specific expert groups voted to include 135 interventions (57%) of a potential 235 interventions collated from stage 2. After synthesis across all interventions and eye conditions, 64 interventions (13 health promotion and education, 6 screening and prevention, 38 treatment, and 7 rehabilitation) were included in the PECI.

Conclusions and Relevance

This systematic review of CPGs for priority eye conditions, followed by an expert consensus procedure, identified 64 essential, evidence-based, eye care interventions that are required to achieve universal eye health coverage. The review identified some important gaps, including a paucity of high-quality, English-language CPGs, for several eye diseases and a dearth of evidence-based recommendations on eye health promotion and prevention within existing CPGs.

Repeatability and Agreement of Horizontal Corneal Diameter Measurements Between Scanning-Slit Topography, Dual Rotating Scheimpflug Camera With Placido Disc Tomography, Placido Disc Topography, and Optical Coherence Tomography

PURPOSE

The purpose of this study was to assess the repeatability and agreement of horizontal white-to-white (WTW) measurements using 4 different imaging modalities including a slit-scanning elevation topographer, dual rotating Scheimpflug camera and Placido Disc tomographer, Placido Disc topographer, and anterior segment optical coherence (OCT) tomographer.

METHODS

In this prospective study, 33 eyes of 33 healthy subjects were scanned 3 times using each of the Orbscan IIz, Sirius, Nidek OPD III, and DRI OCT Triton devices and WTW measurements were recorded. Repeatability was assessed using the intraclass correlation coefficient (ICC), and agreement was analyzed using Bland-Altman plots.

RESULTS

Mean WTW values obtained from the Orbscan IIz, Sirius, Nidek, and DRI OCT Triton devices were 11.76 ± 0.41, 12.10 ± 0.45, 12.14 ± 0.41, and 12.40 ± 0.48 mm, respectively. Overall, there was high repeatability, with the ICC >0.86 for all devices. The Sirius showed the highest repeatability (ICC = 0.993), and the Nidek the lowest (ICC = 0.870). All pairwise comparison showed significant differences in the mean WTW measurements ( P < 0.01) except between Sirius and Nidek ( P = 0.27). Mean differences showed that the DRI OCT Triton had the highest WTW values, followed by Nidek, Sirius, and finally by Orbscan, which provided the lowest measurements. All pairwise comparisons had wide limits of agreements (between 0.60 and 0.80 mm).

CONCLUSIONS

In healthy subjects the 4 devices demonstrated high repeatability in WTW measurement. However, a poor agreement between the devices suggests that they should not be used interchangeably for WTW measurements in clinical practice.

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.

Changes in Corneal Biomechanical Properties After Small-Incision Lenticule Extraction and Photorefractive Keratectomy, Using a Noncontact Tonometer

PURPOSE

The aim of this study was to evaluate and compare early corneal biomechanical changes after small-incision lenticule extraction (SMILE) and photorefractive keratectomy (PRK).

METHODS

The study comprised 74 patients eligible for refractive surgery, equally allocated to PRK (37 patients) and SMILE (37 patients). Corneal biomechanical properties were recorded and compared between the 2 groups at preoperatively and 3 months after surgery using a dynamic ultra-high-speed Scheimpflug camera equipped with a noncontact tonometer.

RESULTS

Both procedures significantly affected corneal biomechanical properties at 3 months after surgery. Patients in the PRK group showed significantly better results for deformation amplitude ratio (DA ratio) ( P = 0.03), maximum inverse radius (InvRadMax) ( P = 0.02), and A2 time ( P = 0.03). The mean changes in DA ratio, HC radius, InvRadMax, and Ambrosio relational thickness were significantly higher in the SMILE group in comparison with those of the PRK group (all, P < 0.05). In both groups, change in CCT was significantly correlated with changes in DA ratio and InvRadMax ( P < 0.05).

CONCLUSIONSS

Both SMILE and PRK refractive surgeries significantly altered corneal biomechanical properties but the changes were more prominent after SMILE.

Flattening of Central, Paracentral, and Peripheral Cones After Non-accelerated and Accelerated Epithelium-off CXL in Keratoconus: A Multicenter Study

PURPOSE

To assess the flattening of central, paracentral, and peripheral cones following non-accelerated (non-A-CXL) and accelerated (A-CXL) epithelium-off corneal cross-linking with 10 times higher intensity.

METHODS

In this multicenter study of 200 eyes (100 in each group), following 10 minutes of soak time with riboflavin 0.1%, continuous CXL was performed for 30 minutes (intensity: 3 mW/cm², fluence: 5.4 J/cm²) in the non-A-CXL group and 3 minutes (intensity: 30 mW/cm², fluence: 5.4 J/cm²) in the A-CXL group. Anterior and posterior cone flattening were compared at 12 months. Multiple regression analysis was performed to establish correlation of age, sex, cone location, and preoperative maximum keratometry (Kmax) values with postoperative flattening at 12 months.

RESULTS

In the non-A-CXL and A-CXL groups, central cones were the steepest, followed by paracentral and peripheral cones. Both groups showed significant flattening in central (1.54 ± 1.94 and 1.09 ± 1.79 diopters [D]) and paracentral (0.62 ± 1.59 and 0.55 ± 0.98 D) cones only. In the non-A-CXL group, there was a positive correlation between postoperative flattening and preoperative Kmax values, whereas paracentral and peripheral cone locations were negatively related. In the A-CXL group, only paracentral location was negatively correlated to postoperative flattening and showed posterior cone steepening at 12 months.

CONCLUSIONS

Although central cones were the steepest in both groups, there was no difference in postoperative flattening between the groups for all cone locations. In the non-A-CXL group, postoperative flattening was proportional to preoperative Kmax values in central cones and was less with paracentral and peripheral locations. With A-CXL, postoperative flattening was less only with paracentral location. In the A-CXL group, significant posterior cone steepening was noticed only in paracentral cones. [J Refract Surg. 2022;38(5):310-316.].

Effect of oral vitamin D supplementation on dry eye disease patients with vitamin D deficiency

CLINICAL RELEVANCE

Dry eye disease (DED) and vitamin D deficiency are both common clinical entities. Vitamin D has been reported to play a significant role in ocular surface homeostasis.

BACKGROUND

This study aimed to determine the therapeutic effect of oral vitamin D supplementation in dry eye disease patients with vitamin D deficiency.

METHODS

A randomized, controlled study was completed in 100 patients with dry eye disease and concurrent vitamin D deficiency (< 20 ng/ml). Participants were randomly allocated to 8 weeks of oral vitamin D supplementation with both groups receiving conventional dry eye treatment with artificial tears. Schirmer's, tear break-up time (TBUT) and osmolarity tests were measured before and after eight weeks of treatment.

RESULTS

The mean age of participants was 36.8 ± 8.56 years in the treatment group (n: 50) and 34.8 ± 10.13 year in the control group (n: 50). After eight weeks of treatment the mean differences in Schirmer's, TBUT and tear osmolarity were 2.38 ± 1.55 mm, 3.95 ± 1.48 s and -16.9 ± 6.28 mOsm/L, respectively in the treatment group, and 0.7 ± 0.86 mm, 0.92 ± 1.57s and -3.34 ± 2.0 mOsm/L respectively in the control group (p < 0.001 for all parameters). The treatment group demonstrated a more significant improvement than the control group in Schirmer<apos;>s, TBUT and osmolarity values (p < 0.001).

CONCLUSION

Vitamin D supplementation as an adjuvant to routine dry eye treatment improves ocular surface hemostasis parameters, results in better tear stability and a more improved tear osmolarity in patients with vitamin D deficiency.

The Aotearoa Research Into Keratoconus Study: Geographic Distribution, Demographics, and Clinical Characteristics of Keratoconus in New Zealand

PURPOSE

To investigate the epidemiologic, demographic, and basic clinical characteristics of individuals with keratoconus managed by optometrists in New Zealand (NZ)/Aotearoa.

METHODS

A prospective, longitudinal, nationwide, survey protocol was completed for every patient with keratoconus who underwent a consultation with participating optometrists in a 2-year period. Data for each patient included date of birth, sex, self-reported ethnicity, new or previous diagnosis, uncorrected (UCVA) and best-corrected visual acuity (BCVA), type of refractive correction required to obtain BCVA and keratometric readings obtained using keratometry or computerized topography.

RESULTS

One thousand eight hundred sixty-nine cases were identified, with a mean age of 41.0 ± 15.7 years, 56.4% being men, and 87.3% with previous diagnosis. The distribution of cases was skewed toward Auckland (41.6%), Waikato (21.3%), Wellington (16.8%), and Bay of Plenty (13.3%). Self-reported ethnicities were predominantly NZ European (54.4%), Māori (24.7%), and Pacific Peoples (15.5%), disproportionate to the general population profile (74.0%, 14.9%, and 7.4% respectively). Most eyes (64.3%) were managed with rigid contact lenses (corneal lens in 34.2%). The mean K-mean was 49.0 ± 5.7 D. The mean UCVA was 6/42 and BCVA was 6/9. Māori and Pacific Peoples had both the highest K-mean and proportions of eyes graded stage IV on the Amsler-Krumeich scale.

CONCLUSIONS

The results indicate that keratoconus is relatively common in NZ with at least 1869 patients managed by optometrists in 2 years. Most eyes had mild to moderate disease; however, Māori and Pacific Peoples seem to have greater disease severity. An ethnic predilection is apparent, with Māori and Pacific Peoples overrepresented relative to their population proportions, reinforcing a long-held clinical suspicion.

Prospective one year study of corneal biomechanical changes following high intensity, accelerated cornea cross-linking in patients with keratoconus using a non-contact tonometer

PURPOSE

To characterize corneal biomechanical properties utilizing a dynamic ultra-high-speed Scheimpflug camera equipped with a non-contact tonometer (CorVis ST, CST) in keratoconic corneas following continuous high intensity, high irradiance corneal cross-linking.

DESIGN

Prospective longitudinal single-centre study at a tertiary referral center.

METHODS

Corneal biomechanical properties were measured in patients with progressive keratoconus undergoing high intensity (30 mW/cm2), high irradiance (5.4 J/cm2), accelerated corneal cross-linking with continuous exposure to ultraviolet-A for 4 min. CST was used to assess corneal biomechanical properties pre-operatively and at 1, 3, 6 and 12 months post-operatively. CST output videos were further analyzed using several previously reported algorithms.

RESULTS

A total of 25 eyes of 25 participants were examined. The mean age of participants was 20.9 ± 5.3 years; 56% were male and 80% were of Māori or Pacific Island origin. Energy absorbed area (mN mm), was the only significantly changed parameter compared to baseline at all time points measuring 3.61 ± 1.19 preoperatively, 2.81 ± 1.15 at 1 month (p = 0.037), 2.79 ± 0.81 (p = 0.033) at 3 months, 2.76 ± 0.95 (p = 0.028) at 6 months and 2.71 ± 1.18 (p = 0.016) at 12 months.

CONCLUSIONS

The significant difference between the pre and post-operative energy absorbed area appears to reflect changes in corneal viscous properties that occur following corneal cross-linking.

Repeatability and agreement of white-to-white measurements between slit-scanning tomography, infrared biometry, dual rotating Scheimpflug camera/Placido disc tomography, and swept source anterior segment optical coherence tomography

Purpose

To assess the agreement and repeatability of horizontal visible iris diameter (HVID) or white-to-white (WTW) measurements between four imaging modalities; combination slit scanning elevation/Placido tomography, infrared biometry, dual rotating scheimpflug camera/Placido tomography, and swept source anterior segment optical coherence tomography (AS-OCT).

Methods

A prospective study of 35 right eyes of healthy volunteers were evaluated using the Orbscan IIz, IOL Master 700, Galilei G2, and DRI Triton OCT devices. The inter-device agreement and repeatability of HVID/WTW measurements for each device were analysed.

Results

Mean HVID/WTW values obtained by the Orbscan IIz, IOL Master 700, Galilei G2 and DRI Triton OCT were 11.77 ± 0.40 mm, 12.40 ± 0.43 mm, 12.25 ± 0.42 mm, and 12.42 ± 0.47 mm, respectively. All pairwise comparisons revealed statistically significant differences in mean HVID/WTW measurements (p = <0.01) except for the IOL Master 700—DRI OCT Triton pair (p = 0.56). Mean differences showed that the DRI Triton OCT produced the highest HVID/WTW values, followed by the IOL Master 700, Galilei G2 and Orbscan IIz, respectively. The limits of agreement were large on all device pairs. There was high repeatability for all devices (ICC ≥ 0.980). The highest repeatability was seen in the Galilei G2 (ICC = 0.995) and lowest in the Orbscan IIz (ICC = 0.980).

Conclusions

The four devices exhibit high repeatability, but should not be used interchangeably for HVID/WTW measurements in clinical practice.

Keratoconus detection of changes using deep learning of colour-coded maps

Objective

To evaluate the accuracy of convolutional neural networks technique (CNN) in detecting keratoconus using colour-coded corneal maps obtained by a Scheimpflug camera.

Design

Multicentre retrospective study.

Methods and analysis

We included the images of keratoconic and healthy volunteers’ eyes provided by three centres: Royal Liverpool University Hospital (Liverpool, UK), Sedaghat Eye Clinic (Mashhad, Iran) and The New Zealand National Eye Center (New Zealand). Corneal tomography scans were used to train and test CNN models, which included healthy controls. Keratoconic scans were classified according to the Amsler-Krumeich classification. Keratoconic scans from Iran were used as an independent testing set. Four maps were considered for each scan: axial map, anterior and posterior elevation map, and pachymetry map.

Results

A CNN model detected keratoconus versus health eyes with an accuracy of 0.9785 on the testing set, considering all four maps concatenated. Considering each map independently, the accuracy was 0.9283 for axial map, 0.9642 for thickness map, 0.9642 for the front elevation map and 0.9749 for the back elevation map. The accuracy of models in recognising between healthy controls and stage 1 was 0.90, between stages 1 and 2 was 0.9032, and between stages 2 and 3 was 0.8537 using the concatenated map.

Conclusion

CNN provides excellent detection performance for keratoconus and accurately grades different severities of disease using the colour-coded maps obtained by the Scheimpflug camera. CNN has the potential to be further developed, validated and adopted for screening and management of keratoconus.

Repeatability of corneal and epithelial thickness measurements with anterior segment optical coherence tomography in keratoconus

PURPOSE

To investigate the repeatability in corneal thickness (CT) and epithelial thickness (ET) measurements using spectral domain anterior segment optical coherence tomography (AS-OCT, REVO NX, Optopol) in keratoconus, and examine the effect of corneal crosslinking (CXL) on repeatability.

METHODS

A cross-sectional study of 259 eyes of 212 patients with keratoconus attending the corneal disease clinic at a university hospital tertiary referral center were enrolled. Two groups were analysed: eyes with no prior history of CXL (Group A) and eyes with prior CXL (Group B). Repeatability of measurements was assessed using the intraclass correlation coefficient (ICC) and coefficient of variation (CV).

RESULTS

In Group A, central corneal thickness (CCT) was 472.18 ± 45.41μm, and the ET was found to be the thinnest in the inferior-temporal aspect at 51.79 ± 5.97μm and thickest at the superior-nasal aspect at 56.07 ± 5.70μm. In Group B, CCT was 465.11± 42.28μm, and the ET was the thinnest at the inferior-temporal aspect at 50.63 ± 5.52μm and thickest at the superior aspect at 56.80 ± 6.39μm. When evaluating CT measurements, ICC was above 0.86 and 0.83 for Group A and Group B respectively. When evaluating ET measurements, ICC was above 0.82 for both groups. CXL had no statistically significant impact on the repeatability of measurements.

CONCLUSIONS

AS-OCT provides repeatable CT and ET measurements in the central and peripheral cornea in patients with keratoconus. Repeatability is not affected by a history of CXL.

Repeatability and agreement of biometric measurements using spectral domain anterior segment optical coherence tomography and Scheimpflug tomography in keratoconus

Purpose

To compare the repeatability and agreement in biometric measurements using Spectral Domain Anterior Segment OCT (AS-OCT, REVO-NX, Optopol) and Scheimpflug tomography (Pentacam-AXL, Oculus) in keratoconus.

Methods

Prospective case series at a university hospital tertiary center. Axial length (AL), anterior chamber depth (ACD), central corneal thickness (CCT), and thinnest corneal thickness (TCT) were measured using both devices in patients with keratoconus. Three groups were analyzed: eyes with no prior crosslinking or contact lens wear (Group A), eyes with prior crosslinking (Group B), and eyes with prior contact lens wear (Group C). Repeatability and agreement of measurements were analyzed.

Results

The study comprised of 214 eyes of 157 subjects. In Group A (n = 95 eyes), Group B (n = 86 eyes), and Group C (n = 33 eyes), intraclass correlation coefficient (ICC) was higher than 0.90 for all examined parameters, except for ACD readings in Group A with the REVO-NX (ICC = 0.83). Differences in ACD, TCT, and CCT were significantly different between the two devices for Groups A, B and C (p<0.05). AL measurements differed significantly in Groups A and B (p<0.05) but not in Group C (p = 0.18). Repeatability did not vary significantly between Groups A, B, or C in any parameter with both devices (p>0.05). There was poor agreement between the two devices across all parameters (p<0.05).

Conclusions

Both devices demonstrated good repeatability but poor agreement across AL, ACD, CCT and TCT measurements. There was no significant difference in repeatability in virgin eyes compared to eyes with prior crosslinking or contact lens wear, however, the interchangeable use of the two devices is not recommended.

Corneal Biomechanical Properties in Varying Severities of Myopia

Purpose: To investigate corneal biomechanical response parameters in varying degrees of myopia and their correlation with corneal geometrical parameters and axial length.

Methods: In this prospective cross-sectional study, 172 eyes of 172 subjects, the severity degree of myopia was categorized into mild, moderate, severe, and extreme myopia. Cycloplegic refraction, corneal tomography using Pentacam HR, corneal biomechanical assessment using Corvis ST and Ocular Response Analyser (ORA), and ocular biometry using IOLMaster 700 were performed for all subjects. A general linear model was used to compare biomechanical parameters in various degrees of myopia, while central corneal thickness (CCT) and biomechanically corrected intraocular pressure (bIOP) were considered as covariates. Multiple linear regression was used to investigate the relationship between corneal biomechanical parameters with spherical equivalent (SE), axial length (AXL), bIOP, mean keratometry (Mean KR), and CCT.

Results: Corneal biomechanical parameters assessed by Corvis ST that showed significant differences among the groups were second applanation length (AL2, p = 0.035), highest concavity radius (HCR, p < 0.001), deformation amplitude (DA, p < 0.001), peak distance (PD, p = 0.022), integrated inverse radius (IR, p < 0.001) and DA ratio (DAR, p = 0.004), while there were no significant differences in the means of pressure-derived parameters of ORA between groups. Multiple regression analysis showed all parameters of Corvis ST have significant relationships with level of myopia (SE, AXL, Mean KR), except AL1 and AL2. Significant biomechanical parameters showed progressive reduction in corneal stiffness with increasing myopia (either with greater negative SE or greater AXL), independent of IOP and CCT. Also, corneal hysteresis (CH) or ability to dissipate energy from the ORA decreased with increasing level of myopia.

Conclusions: Dynamic corneal response assessed by Corvis ST shows evidence of biomechanical changes consistent with decreasing stiffness with increasing levels of myopia in multiple parameters. The strongest correlations were with highest concavity parameters where the sclera influence is maximal.

Case Report: Successful Corneal Crosslinking in a Patient with Corneal Ectasia Associated with Stevens-Johnson Syndrome

SIGNIFICANCE

Corneal ectasia can be a complication of Stevens-Johnson syndrome. When detected in a timely manner, corneal crosslinking can be a safe treatment. This is an important association to highlight that early diagnosis and treatment can prevent the need for invasive surgical procedures such as keratoplasty.

PURPOSE

This study aimed to report a successful accelerated epithelium-off corneal crosslinking in a rare case of corneal ectasia secondary to Stevens-Johnson syndrome.

CASE REPORT

A 25-year-old Indian man presented with a progressive visual acuity decline 5 years after an acute episode of Stevens-Johnson syndrome secondary to penicillin ingestion. Serial tomography scans confirmed the diagnosis of corneal ectasia. After the preparation of the ocular surface, which was deemed to have a mild degree of limbal stem cell deficiency, with frequent preservative-free lubrication and steroid use, accelerated epithelium-off crosslinking was performed with 4 minutes of continuous ultraviolet-A exposure at 30 mW/cm2 and a total energy dose of 7.2 J/cm2. Complete re-epithelialization was observed at 72 hours after crosslinking with no complications. Corneal tomography 15 months after treatment showed stabilization of ectasia, with improvement in visual acuity.

CONCLUSIONS

Corneal ectasia is a rare but important complication of Stevens-Johnson syndrome. Accelerated epithelium-off crosslinking treatment can be considered in patients with a compromised ocular surface after Stevens-Johnson syndrome. Pre-operative optimization of the ocular surface and vigilant monitoring in the early post-operative period are recommended for the prevention of complications.

Corneal transplantation after failed grafts: Options and outcomes

Corneal transplantation is the most commonly performed human tissue transplantation procedure worldwide. Because of the large number of transplants, corneal graft failure has become one of the most common indications for corneal transplantation. The relatively recently developed lamellar transplant techniques have brought about specific potential complications leading to graft failure that may require different approaches to repeat transplantation other than penetrating keratoplasty. On the other hand, these new lamellar techniques also provide novel ways of rescuing failed penetrating grafts, with potential advantages over successive penetrating keratoplasties, such as reduced intraoperative risks and faster visual rehabilitation. We summarize the incidence and risk factors of graft failure for penetrating and lamellar (stromal and endothelial) corneal transplants and discuss the various surgical alternatives currently available to rescue such failed grafts, with a focus on the reported outcomes and limitations.

Microdroplet and spatter contamination during phacoemulsification cataract surgery in the era of COVID-19

IMPORTANCE

Determine phacoemulsification cataract surgery risk in a Covid-19 era.

BACKGROUND

SARS-CoV-2 (Covid-19) transmission via microdroplet and aerosol-generating procedures presents risk to medical professionals. As the most common elective surgical procedure performed globally; determining contamination risk from phacoemulsification cataract surgery may guide personal protection equipment use.

DESIGN

Pilot study involving phacoemulsification cataract surgery on enucleated porcine eyes by experienced ophthalmologists in an ophthalmic operating theatre.

PARTICIPANTS

Two ophthalmic surgical teams.

METHODS

Standardized phacoemulsification of porcine eyes by two ophthalmologists accompanied by an assistant. Fluorescein incorporated into phacoemulsification irrigation fluid identifying microdroplets and spatter. Contamination documented using a single-lens reflex camera with a 532 nm narrow bandpass (fluorescein) filter, in-conjunction with a wide-field blue light and flat horizontal laser beam (wavelength 532 nm). Quantitative image analysis using Image-J software.

MAIN OUTCOME MEASURES

Microdroplet and spatter contamination from cataract phacoemulsification.

RESULTS

With phacoemulsification instruments fully within the eye, spatter contamination was limited to <10 cm. Insertion and removal of the phacoemulsification needle and bimanual irrigation/aspiration, with irrigation active generated spatter on the surgeons' gloves and gown extending to >16 cm below the neckline in surgeon 1 and > 5.5 cm below the neckline of surgeon 2. A small tear in the phacoemulsification irrigation sleeve, presented a worse-case scenario the greatest spatter. No contamination above the surgeons' neckline nor contamination of assistant occurred.

CONCLUSIONS AND RELEVANCE

Cataract phacoemulsification generates microdroplets and spatter. Until further studies on SARS-CoV-2 transmission via microdroplets or aerosolisation of ocular fluid are reported, this pilot study only supports standard personal protective equipment.

Measurement of refractive, wavefront, topographic, and keratometric changes attributable to epithelial removal in keratoconus

OBJECTIVE

The corneal epithelium is able to mask topographic and keratometric abnormalities of the underlying Bowman layer in keratoconus, but its contribution to refractive and wavefront parameters has not yet been studied. This study compared the refractive and aberrometric features of the corneal epithelium and Bowman layer in eyes with keratoconus before and after epithelial debridement.

METHODS

Corneal refractive and wavefront variables were measured in patients with keratoconus undergoing corneal crosslinking-immediately before and after epithelial debridement using a third-generation combined corneal topographer, autorefractor, and aberrometer.

RESULTS

After epithelial debridement, there were significant changes in spherical equivalent (-1.37 D; p < 0.01) and asphericity (-0.64; p = 0.03). The mean difference in the magnitude of epithelium-induced astigmatism in the 3rd and 5th central millimeter rings was 0.44 ± 3.20 D × 8 and 0.43 ± 2.75 D × 21 (positive cylinder), respectively. Corneal astigmatism axis shifted in the against-the-rule orientation after epithelial debridement. There were no significant changes in any corneal higher-order aberration parameter after epithelial debridement (p > 0.05).

CONCLUSIONS

In eyes with keratoconus, epithelial debridement increased the magnitude of anterior corneal prolateness and tended to increase astigmatism and shift its axis toward the against-the-rule orientation. This study supports the notion that the corneal epithelium smooths underlying Bowman layer irregularity in keratoconus.

Outcomes in randomised controlled trials of multifocal lenses in cataract surgery: the case for development of a core outcome set

BACKGROUND/AIMS

To describe and summarise the outcomes reported in randomised controlled trials of multifocal versus monofocal intraocular lenses in cataract surgery.

METHODS

We identified all randomised controlled trials of multifocal versus monofocal lenses in a Cochrane review (last search date June 2016). We extracted and summarised data on all outcomes reported using the framework of domain, measurement, metric and method of aggregation.

RESULTS

All studies collected data on distance and near visual acuity but there was considerable variation in the measures used and whether these outcomes were unaided or best corrected. Most studies reported final value measurements, rather than change from baseline. Approximately half of the studies reported data as a continuous measure only, one-third reported both continuous and categorical measures and a minority reported categorical measures only. There was little consensus as to cut-points. Although a majority of studies included one or more patient-reported outcome measures, none of the studies reported patient involvement in the choice of outcomes.

CONCLUSION

The collection and analysis of data on outcome measures in studies of multifocal intraocular lenses in cataract surgery are complicated. As a result, there is considerable heterogeneity in collection and reporting in the medical literature. This makes it difficult to synthesise such data to provide robust estimates of effect and is a potential source of research waste. Investigators in this field must produce a core outcome set that is informed by patients' views and we propose an initial set of outcomes on which these could be based.

Peripheral Cornea Crosslinking Before Deep Anterior Lamellar Keratoplasty

Since Cornea crosslinking (CXL) has been proven to halt progression and biomechanically stabilize keratoconus, we hypothesized that CXL of the corneal periphery 3 months prior to corneal transplantation can reduce the incidence of recurrent ectasia by strengthening the peripheral corneal tissue and causing apoptosis of diseased peripheral host keratocytes. Thus, the aim of this case-report was to propose a novel peripheral CXL technique prior to keratoplasty and evaluate its safety. A 22-year-old woman was admitted with advanced right keratoconus and corrected distance visual acuities of 20/30 in the right eye and 20/200 in the left eye with a manifest refraction of -3.00D/ -8.00D × 36° and -17.00D/ -11.50D × 90°, respectively. The proposed treatment involved crosslinking of peripheral corneal tissue (6.5-9.5mm), sparing the central cornea and limbus, three months prior to corneal transplantation as a means of biomechanically strengthening the peripheral cornea tissue. This procedure was feasible and safe with repopulation of the peripheral cornea with keratocytes, no significant endothelial cell loss and a routine postoperative course following CXL and DALK. This method might reduce or eliminate the need for repeat corneal transplantation in patients with recurrent ectasia. Further studies are needed to confirm the results.

Comparison of corneal biomechanical properties following penetrating keratoplasty and deep anterior lamellar keratoplasty for keratoconus

IMPORTANCE

Keratoplasty is a surgical procedure to create a more regular optical surface following biomechanical weakening of the cornea in keratoconus. The ideal keratoplasty procedure should also restore corneal biomechanics to that of the healthy cornea.

BACKGROUND

This study aimed to evaluate and compare the biomechanical properties of corneas following penetrating keratoplasty (PKP) and predescematic deep anterior lamellar keratoplasty (DALK) to those of healthy eyes.

DESIGN

Prospective cross-sectional study.

PARTICIPANTS

Two cohorts of post-keratoplasty eyes (42 eyes with PKP and 27 eyes with DALK) with each other, and with a cohort of 152 healthy eyes.

METHODS

All eyes were examined by slit-lamp biomicroscopy, tomography, anterior segment-OCT and non-contact tonometry CorVis ST (CST).

MAIN OUTCOME MEASURES

CST biomechanical parameters, maximum corneal deformation (MCD) and corneal energy dissipation were compared between keratoplasty techniques, and with healthy eyes.

RESULTS

The mean age of participants with PKP and DALK were 35 ± 13.7 and 36.1 ± 12.6 years, respectively. None of the CST parameters were significantly different between PKP and DALK eyes. However, when compared to healthy corneas, numerous parameters were significantly different for both keratoplasty techniques. Of note, MCD was significantly higher in PKP compared to DALK and healthy corneas, after controlling for co-factors.

CONCLUSIONS AND RELEVANCE

Neither type of keratoplasty technique utilized in keratoconus completely restored corneal biomechanical properties to that of healthy corneas. However, PKP resulted in a greater number of parameters significantly different to healthy corneas, compared to DALK.

Direct measurement of anterior corneal curvature changes attributable to epithelial removal in keratoconus

PURPOSE

To compare the tomography of the corneal epithelium and Bowman layer in eyes with moderate to severe keratoconus before and after epithelial debridement.

SETTING

University hospital tertiary referral center.

DESIGN

Prospective case series.

METHODS

Dual-channel Scheimpflug combined with Placido-disk tomography was used to measure the corneal variables in eyes with keratoconus having corneal crosslinking immediately before and after epithelial debridement. The differences in pachymetry, axial keratometry, astigmatism magnitude, asphericity, total corneal power, and spherical aberrations were computed.

RESULTS

The study comprised 30 eyes of 30 patients. After epithelial removal, the central (0.0 to 4.0 mm) and midperipheral (4.0 to 7.0 mm) corneal zones were significantly thinner mean (21 μm ± 14 [SD] and 35 ± 44 μm, respectively). The mean anterior axial flat keratometry (K) (+1.71 diopters [D]), steep K (+2.14 D), maximum K (+2.13 D), corneal astigmatism (+1.11 D), asphericity (-0.31), and total corneal power changes (+2.03 D) were significantly different after epithelial debridement. There were no significant changes in posterior corneal flat K or steep K, posterior corneal astigmatism, or posterior asphericity. There were no significant differences in the mean astigmatic axis (anterior or posterior corneal surface) or spherical aberration after epithelial debridement.

CONCLUSIONS

In eyes with moderate to severe keratoconus, the tomography of Bowman layer was significantly steeper than that of the epithelium; thus, epithelial debridement increased the magnitude of anterior corneal keratometry, astigmatism, and prolateness. These data suggest that the corneal epithelium smooths the underlying Bowman layer irregularity in keratoconus.

Prospective 2-year study of accelerated pulsed transepithelial corneal crosslinking outcomes for Keratoconus

AIMS

To report 2-year outcomes of transepithelial, accelerated, pulsed, corneal crosslinking (t-ACXL) for patients with progressive keratoconus.

METHODS

Prospective, interventional case series at a university hospital tertiary referral centre. Forty eyes with progressive keratoconus undergoing t-ACXL were included. Treatment was performed with pulsed illumination (1 s on/1 s off) using 45 mW/cm² for 5 min and 20 s, for a surface dose of 7.2 J cm². Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction spherical equivalent (MRSE), corneal tomography, anterior segment optical coherence tomography (OCT) and confocal microscopy were evaluated preoperatively and at 12 and 24 months postoperatively.

RESULTS

The mean patient age was 23.32 ± 5.18 years (SD) (range 14-42 years). The mean CDVA significantly improved from 0.38 ± 0.32 logMAR at baseline to 0.30 ± 0.21 logMAR at 24 months (P < 0.01). There was no significant difference in UDVA, MRSE, asymmetry indices, tomographic parameters and endothelial density. The improvement in visual acuity was inversely correlated with preoperative CDVA and preoperative K_Max. No complications were encountered.

CONCLUSIONS

In this prospective study, t-ACXL appeared safe and effective in halting progression of keratoconus within a follow-up period of 24 months.

Wound healing in the eye: Therapeutic prospects

In order to maintain a smooth optical surface the corneal epithelium has to continuously renew itself so as to maintain its function as a barrier to fluctuating external surroundings and various environmental insults. After trauma, the cornea typically re-epithelializes promptly thereby minimizing the risk of infection, opacification or perforation. A persistent epithelial defect (PED) is usually referred to as a non-healing epithelial lesion after approximately two weeks of treatment with standard therapies to no avail. They occur following exposure to toxic agents, mechanical injury, and ocular surface infections and are associated with significant clinical morbidity in patients, resulting in discomfort or visual loss. In the case of deeper corneal injury and corneal pathology the wound healing cascade can also extend to the corneal stroma, the layer below the epithelium. Although significant progress has been made in recent years, pharmaco-therapeutic agents that promote corneal healing remain limited. This article serves as a review of current standard therapies, recently introduced alternative therapies gaining in popularity, and a look into the newest developments into ocular wound healing.

Descemet's membrane macroperforation during interface irrigation in big bubble deep anterior lamellar keratoplasty

This report describes the macroperforation of descemet's membrane (DM) during irrigation of the interface following successful removal of stromal tissue in big bubble (BB) deep anterior lamellar keratoplasty (DALK). A 42-year-old woman with keratoconus underwent a BB DALK procedure. After successful formation of Type 2 bubble and removal of stromal tissue, interface irrigation was performed to remove residual viscoelastic. This led to a macroperforation of DM, and the case was converted to penetrating keratoplasty. To the best of our knowledge, this is the first report of such a complication in the literature. Recognition of a 2 bubble formation during pneumodissection should alert the surgeon to a high risk of DM rupture. We advise against the removal of DM from the donor in such cases as an added measure of safety.

Multifocal versus monofocal intraocular lenses after cataract extraction

BACKGROUND

Good unaided distance visual acuity (VA) is now a realistic expectation following cataract surgery and intraocular lens (IOL) implantation. Near vision, however, still requires additional refractive power, usually in the form of reading glasses. Multiple optic (multifocal) IOLs are available which claim to allow good vision at a range of distances. It is unclear whether this benefit outweighs the optical compromises inherent in multifocal IOLs.

OBJECTIVES

To assess the visual effects of multifocal IOLs in comparison with the current standard treatment of monofocal lens implantation.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (2016, Issue 5), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to June 2016), Embase (January 1980 to June 2016), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov), and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 13 June 2016.

SELECTION CRITERIA

All randomised controlled trials comparing a multifocal IOL of any type with a monofocal IOL as control were included. Both unilateral and bilateral implantation trials were included. We also considered trials comparing multifocal IOLs with "monovision" whereby one eye is corrected for distance vision and one eye corrected for near vision.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. We assessed the 'certainty' of the evidence using GRADE.

MAIN RESULTS

We found 20 eligible trials that enrolled 2230 people with data available on 2061 people (3194 eyes). These trials were conducted in Europe (13), China (three), USA (one), Middle East (one), India (one) and one multicentre study in Europe and the USA. Most of these trials compared multifocal with monofocal lenses; two trials compared multifocal lenses with monovision. There was considerable variety in the make and model of lenses implanted. Overall we considered the trials at risk of performance and detection bias because it was difficult to mask participants and outcome assessors. It was also difficult to assess the role of reporting bias.There was moderate-certainty evidence that the distance acuity achieved with multifocal lenses was not different to that achieved with monofocal lenses (unaided VA worse than 6/6: pooled RR 0.96, 95% confidence interval (CI) 0.89 to 1.03; eyes = 682; studies = 8). People receiving multifocal lenses may achieve better near vision (RR for unaided near VA worse than J3/J4 was 0.20, 95% CI 0.07 to 0.58; eyes = 782; studies = 8). We judged this to be low-certainty evidence because of risk of bias in the included studies and high heterogeneity (I² = 93%) although all included studies favoured multifocal lenses with respect to this outcome.People receiving multifocal lenses may be less spectacle dependent (RR 0.63, 95% CI 0.55 to 0.73; eyes = 1000; studies = 10). We judged this to be low-certainty evidence because of risk of bias and evidence of publication bias (skewed funnel plot). There was also high heterogeneity (I² = 67%) but all studies favoured multifocal lenses. We did not additionally downgrade for this.Adverse subjective visual phenomena were more prevalent and more troublesome in participants with a multifocal IOL compared with monofocals (RR for glare 1.41, 95% CI 1.03 to 1.93; eyes = 544; studies = 7, low-certainty evidence and RR for haloes 3.58, 95% CI 1.99 to 6.46; eyes = 662; studies = 7; moderate-certainty evidence).Two studies compared multifocal lenses with monovision. There was no evidence for any important differences in distance VA between the groups (mean difference (MD) 0.02 logMAR, 95% CI -0.02 to 0.06; eyes = 186; studies = 1), unaided intermediate VA (MD 0.07 logMAR, 95% CI 0.04 to 0.10; eyes = 181; studies = 1) and unaided near VA (MD -0.04, 95% CI -0.08 to 0.00; eyes = 186; studies = 1) compared with people receiving monovision. People receiving multifocal lenses were less likely to be spectacle dependent (RR 0.40, 95% CI 0.30 to 0.53; eyes = 262; studies = 2) but more likely to report problems with glare (RR 1.41, 95% CI 1.14 to 1.73; eyes = 187; studies = 1) compared with people receiving monovision. In one study, the investigators noted that more people in the multifocal group underwent IOL exchange in the first year after surgery (6 participants with multifocal vs 0 participants with monovision).

AUTHORS' CONCLUSIONS

Multifocal IOLs are effective at improving near vision relative to monofocal IOLs although there is uncertainty as to the size of the effect. Whether that improvement outweighs the adverse effects of multifocal IOLs, such as glare and haloes, will vary between people. Motivation to achieve spectacle independence is likely to be the deciding factor.

Deep anterior lamellar keratoplasty versus penetrating keratoplasty for treating keratoconus

BACKGROUND

Keratoconus is an ectatic (weakening) disease of the cornea, which is the clear surface at the front of the eye. Approximately 10% to 15% of patients diagnosed with keratoconus require corneal transplantation. This may be full-thickness (penetrating) or partial-thickness (lamellar).

OBJECTIVES

To compare visual outcomes after deep anterior lamellar keratoplasty (DALK) and penetrating keratoplasty for keratoconus, and to compare additional outcomes relating to factors which may contribute to poor visual outcomes (e.g. astigmatism, graft rejection and failure).

SEARCH METHODS

We searched a number of electronic databases including CENTRAL, PubMed and EMBASE without using any date or language restrictions. We last searched the electronic databases on 31 October 2013. We also handsearched the proceedings of several international ophthalmic conferences.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) comparing the outcomes of DALK and penetrating keratoplasty in the treatment of keratoconus.

DATA COLLECTION AND ANALYSIS

Two authors assessed trial quality and extracted data independently. For dichotomous data (graft failure, rejection, achievement of functional vision) results were expressed as odds ratios (ORs) and 95% confidence intervals (CIs). For continuous data (postoperative best corrected visual acuity (BCVA), uncorrected visual acuity (UCVA), keratometric astigmatism and spherical equivalent) results were expressed as mean differences (MDs) and 95% CIs.

MAIN RESULTS

We identified two completed studies, with a total of 111 participants (n = 30 and n = 81), both conducted in Iran, that met our inclusion criteria. Participants had moderate to severe keratoconus pre-operatively and were randomly allocated to receive either DALK or penetrating keratoplasty. Only one eye of each participant was treated as part of the trials. The smaller study had 12 month follow-up data for all participants. For the larger study, four DALK surgeries had to be abandoned due to technical failure and visual and refractive outcomes were not measured in these participants. Follow-up length for the remaining 77 participants ranged from 6.8 to 36.4 months, with all 77 followed for at least three months post-suture removal. Details of the randomisation procedure were unavailable for the smaller study and so sensitivity analyses were conducted to determine if the results from this study had affected the overall results of the review.Neither of the included studies reported a difference between groups on any of the measures of post-graft visual achievement, keratometric astigmatism or spherical equivalent. A single case of graft failure in a penetrating keratoplasty was reported. No postoperative graft failures were reported in the DALK group of either study.Instances of graft rejection were reported in both groups, in both studies. The majority of these cases were successfully treated with steroids. The data, which related to all cases in each study - given that the four cases that did not go ahead as planned had already technically failed without presence of rejection - showed that rejection was less likely to occur in DALK (odds ratio (OR): 0.33, 95% confidence interval (CI) 0.14 to 0.81, GRADE rating: moderate).Results of the sensitivity analysis indicated that inclusion of the Razmju 2011 study did not bias the results with regards to rejection episodes. While sensitivity analysis showed altered results with regards to failure rates, the data available from the Javadi 2010 study alone had a very wide 95% CI, suggesting an imprecise estimate. Therefore, even after removal of the Razmju 2011 data, it is still difficult to draw conclusions regarding superiority of one technique over another with regards to graft failure.DALK was unable to be completed as planned in four cases and in a further three cases, complications during dissection required further intervention. Other adverse events, of varying severity, were reported in both intervention groups with similar frequency. For both types of surgery, these included postoperative astigmatism, steroid induced ocular hypertension and persistent epithelial defects. In recipients of DALK, one participant had interface neovascularisation (a proliferation of blood vessels where the host and donor cornea come together) and one had wrinkling of Descemet's membrane, the basement membrane separating the corneal stroma from the corneal endothelium. In the penetrating keratoplasty groups, one participant required graft resuturing and one had an atonic pupil, a condition in which the pupil dilates and is non-reactive.Overall, the quality of the evidence was rated as very low to moderate, with methodological limitations, incomplete data analysis and imprecision of findings, as well as high risk of bias in several areas for both studies.

AUTHORS' CONCLUSIONS

We found no evidence to support a difference in outcomes with regards to BCVA at three months post-graft or at any of the other time points analysed (GRADE rating: very low). We also found no evidence of a difference in outcomes with regards to graft survival, final UCVA or keratometric outcomes. We found some evidence that rejection is more likely to occur following penetrating keratoplasty than DALK (GRADE rating: moderate). The small number of studies included in the review and methodological issues relating to the two, mean that the overall quality of the evidence in this review is low. There is currently insufficient evidence to determine which technique may offer better overall outcomes - final visual acuity and time to attain this, keratometric stabilisation, risk of rejection or failure, or both, and risk of other adverse events - for patients with keratoconus. Large randomised trials comparing the outcomes of penetrating keratoplasty and DALK in the treatment of keratoconus are needed.

Parotid Duct Repair by Facial Vein Graft versus Gore-Tex, A Sialographic Evaluation

STATEMENT OF PROBLEM

The most common method for parotid duct anastomosis is suturing. A ductal defect of greater than 1cm may prevent a direct anastomosis.

PURPOSE

The goal of this study was a sialographic evaluation to compare repairing a parotid duct with facial vein graft versus Gore-Tex tub in 19 dogs.

MATERIAL AND METHODS

Nineteen dogs were studied in this experimental trial. Extra oral transverse incisions were made in buccal regions bilaterally to expose parotid ducts and a defect (2 cm) was performed in similar areas (right and left). The right resected duct was repaired with facial vein graft and the left anastomosis was performed by using the Gore-Tex tube microscopically. Sialography was used to evaluate the ductal leakage. Statistical analysis was performed, using SPSS software and McNemar's test.

RESULTS

Based on the sialography evaluation; the ductal leakage was seen in five cases (26.31%) on the right side and in seven cases (36.84%) in the left side. Statistical analysis using McNemar's test suggested no statistically significant difference between ductal leakages in right and left parotid ducts (p> 0.05).

CONCLUSION

The results of this study suggest that the efficacies of Gore-Tex tube and vein graft in parotid duct anastomosis are similar, but the use of Gore-Tex tube had a number of advantages, including reduced morbidity of the graft and short operation time.

Corneal inlay implantation in a young pseudophakic patient

We describe the surgical correction of a 32-year-old pseudophakic patient with the Kamra corneal inlay. To our knowledge, this is the youngest patient to have such a procedure.

FINANCIAL DISCLOSURE

Neither author has a financial or proprietary interest in any material or method mentioned.