Orthokeratology practice in children in a university clinic in Hong Kong*

Purposes: The aim of this study was to analyse clinical data of children undergoing orthokeratology (ortho‐k) and to investigate patients’/parents’ perspective on ortho‐k via telephone interviews. Methods: Clinical records of children undergoing ortho‐k from a university optometry clinic were reviewed and the effects of ortho‐k on refraction, vision and cornea were investigated. A telephone interview was conducted to solicit patients’/parents’ perspective of the treatment. Results: One hundred and eight files were reviewed. Median age of the children was nine years (range six to 15); mean (±SD) pre‐treatment refractive sphere was ‐3.56 ± 1.49 D and the median refractive cylinder was ‐0.50 D (range zero to ‐4.25 D). Significant refractive spherical reduction (58 per cent), improvement in unaided vision and corneal topographical changes were noted after only one night of wear. No significant change in astigmatism was found. Corneal staining was the most commonly observed complication with ortho‐k and more than 80 per cent of patients were advised to apply ocular lubricants to loosen the lens before lens removal. Ortho‐k was mainly undertaken for myopic control and about 90 per cent of the respondents reported good/very good unaided vision after ortho‐k and ranked the treatment as satisfactory or very good. Lens binding and ocular discharge were the most frequently reported problems during the treatment. Conclusion: Under close monitoring, overnight ortho‐k is effective and safe for reducing low to moderate myopia and the treatment is well accepted by the children.     

The influence of lens conditioning on signs and symptoms with new hydrogel contact lenses

Background: Daily disposable contact lenses are considered to be the pinnacle of safe contact lens wear, yet it has been suggested that it takes some period of wear for the lens surface to reach optimal compatibility with the ocular surface. This study assesses the influence of brief treatment with a conditioning drop on the ocular response to new contact lenses over a single day of wear. Methods: The study was a single‐masked, paired (contralateral) comparison of the signs and symptoms with wear of new Acuvue 2 contact lenses pretreated with a conditioning agent containing carboxymethylcellulose (carmellose, CMC) against new lenses inserted directly from the blister pack. Sixty‐one subjects participated in the study, of whom 59 were considered eligible for data analysis. Subjects were also divided into symptomatic and asymptomatic lens wearers based on their overall comfort level in lens wear. Symptoms and signs were recorded at lens delivery and following eight hours of wear. Results: A set of slitlamp signs, comprising corneal staining (p < 0.05), limbal redness (p < 0.05), bulbar conjunctival hyperaemia (p < 0.05), bulbar conjunctival staining (p < 0.01) and palpebral conjunctival redness (p < 0.05) showed small but statistically significant (p < 0.05) end‐ofday mean values in favour of the lens that was conditioned with the rewetting agent. These data were supported by the proportion of subjects showing lower gradings with conditioned lenses versus unconditioned lenses, as follows: corneal staining (35 per cent versus 12 per cent, p <0.05), limbal redness (43 per cent versus 22 per cent, p < 0.05), bulbar conjunctival hyperaemia (50 per cent versus 15 per cent, p < 0.05), bulbar conjunctival staining (46 per cent versus 30 per cent, p < 0.1) and palpebral conjunctival hyperaemia (28 per cent versus 17 per cent, NS). For those subjects reporting symptoms with lens wear (n = 12), there was a statistically significant (p < 0.05) preference in terms of comfort as a result of preconditioning. Conclusions: The results of the investigation suggest that use of a conditioning agent can provide a more physiologically suitable environment for a new lens, thereby reducing the clinical signs associated with lens discomfort. The protocol used here, which is based on a statistical paradigm using standard pictorial grading scales, allows high sensitivity in detecting small changes in ocular parameters.     

Confocal microscopic observations of the human cornea following overnight contact lens wear

Background: Striae and folds are observed with a slidamp biomicroscope in the cornea following overnight contact lens wear. These phenomena are poorly understood. The aim of this study is to employ confocal microscopy to observe and document these and other morphological changes in die human cornea following overnight contact lens wear. Methods: Slitlamp biomicroscopy, slit‐scanning confocal microscopy and ultrasonic pachometry were performed on both eyes of 13 subjects (3M, 10F, age 24 ± 3 years) before and after eight hours overnight wear of a ‐3.00 D Bausch & Lomb one day disposable soft contact lens (Dk/t = 15.1 times 10^‐9 (cm/sec) x {ml O²/ml x mmHg)) in one eye; the other non‐lens‐wearing eye acted as a control. Results: Following sleep, both corneas were swollen (lens‐wearing eye 11.8 ± 3.8 per cent; control eye 2.1 ± 1.9 per cent) and the stroma of both corneas displayed an apparent reduction in keratocyte density (lens‐wearing eye 21 per cent; control eye 10 per cent). Folds were observed with the slidamp biomicroscope and long, straight, dark, orthogonal lines were observed widi die confocal microscope, in the posterior stroma of the oedematous lens‐wearing eyes. Such features were not observed in die control eyes. The keratocytes appeared less distinct with greater levels of corneal oedema. Conclusion: The apparent loss of keratocytes following overnight lens wear is an optical artefact that can be explained in terms of corneal oedema causing volumetric tissue expansion and a loss of optical clarity, which hampers keratocyte detection. These findings place the onus on researchers postulating a loss of stromal keratocytes following clinical interventions, such as contact lens wear, to account for the effects of oedema.     

The ocular response to extended wear of a high Dk silicone hydrogel contact lens

Purpose: A four‐month extended wear clinical trial was conducted to compare die ocular effects of a high Dk Balafilcon A silicone hydrogel lens and a low Dk HEMA 38.6 per cent H²O soft lens. Method: Twenty‐four subjects who were adapted to daily wear of soft lenses wore a high Dk lens in one eye and a low Dk HEMA lens in the other eye for four months on an extended wear basis after one week of daily wear. Thirteen progress evaluations were conducted using standard clinical procedures. Results: Eighteen subjects (75 per cent) completed the study. The high Dk lens induced significantly less bulbar and limbal injection and corneal vascularisation dian the low Dk HEMA lens (p < 0.05). Epithelial microcysts were observed only in the eyes wearing the low Dk lens. A significant increase in myopia was found in die eyes wearing die low Dk HEMA lens (mean = 0.50 D, p < 0.01) compared to die insignificant myopic increase of 0.06 D in the eyes wearing the high Dk lens. Three subjects developed small infiltrates in the high Dk lens wearing eyes and significantly more post‐lens debris was observed under the high Dk lens. Six subjects developed papillary conjunctivitis in die eye wearing silicone hydrogel lenses but only two of those were discontinued from the study. Conclusion: No hypoxia‐related effects were observed with extended wear of the high Dk Balafilcon A silicone hydrogel lens.     

Inter‐observer variability of central corneal thickness measurements using non‐contact specular microscopy after laser in situ keratomileusis

Background: The aim of this study was to investigate the inter‐observer variability of central corneal thickness measurements carried out with a non‐contact specular microscope in patients who had undergone myopic laser in situ keratomileusis. Methods: Twenty‐six eyes of 26 subjects who had undergone myopic laser in situ keratomileusis were studied with the Topcon SP‐2OOOP non‐contact specular microscope (Topcon Corp, Tokyo, Japan). The mean of three consecutive measurements of the central corneal thickness was recorded by two investigators prior to and one month after myopic laser in situ keratomileusis. Results obtained by each of the two physicians were compared. Results: Prior to surgery the mean central corneal thickness was 536.2± 22.2 μm for physician 1 and 536.3 ± 22.2 μm for physician 2 (p = 0.980). The pre‐operative 95 per cent confidence interval was 522.7 to 544.2 μm (physician 1) and 523.1 to 544.1 μm (physician 2). The mean central corneal thickness was 485.8 ± 29.3 μm for physician 1 and 485.6 ± 28.0 μm for physician 2 one month after laser in situ keratomileusis (p = 0.977). The post‐operative 95 per cent confidence intervals were 470.1 to 496.2 μm and 470.3 to 495.4 μm for physicians 1 and 2, respectively. Conclusion: Central corneal thickness measurements can be carried out by different clinicians after laser in situ keratomileusis with non‐contact specular pachymetry, without there being any significant differences among them.     

全角膜羊膜覆盖和绷带型角膜接触镜用于较大翼状胬肉切除术的疗效比较

目的：针对较大翼状胬肉,采用胬肉切除、角膜缘干细胞移植联合全角膜羊膜覆盖术,或胬肉切除和角膜缘干细胞移植术后配戴绷带型角膜接触镜进行治疗,观察两种方法的临床效果。

方法：将侵及瞳孔区的较大翼状胬肉40眼随机分成两组,一组行翼状胬肉切除、角膜缘干细胞移植术联合全角膜羊膜覆盖术(羊膜组),另一组行胬肉切除和角膜缘干细胞移植术后配戴绷带型角膜接触镜(绷带镜组),每组各20眼。比较两组患者手术时间,以及术后第1、3d,1、3wk眼部舒适程度和角膜愈合情况与随访复发情况等。

结果：平均手术时间：羊膜组为61.4±5.2min,绷带镜组为34.5±2.7min,绷带镜组手术时间明显缩短,两组差异有统计学意义(P<0.05)。两组患者的眼部舒适度在术后第1d无明显差异,但在术后第3d和术后1wk,绷带镜组患者的眼部舒适度明显优于羊膜组(P<0.01),至术后3wk时两组间差异无统计学意义(P>0.05)。术后3wk时两组患者的角膜愈合率评分分别为0.85±0.18分和1.15±0.18分,两组差异无统计学意义(P=0.25)。羊膜组有1眼胬肉复发。

结论：在侵及角膜的较大翼状胬肉治疗中,胬肉切除和角膜缘干细胞移植术后联合全角膜羊膜覆盖或术后配戴绷带型角膜接触镜均有助于缓解眼部不适症状和促进角膜创面修复,使用绷带型角膜接触镜患者更舒适,治疗更便捷。     

Ocular refractive and biometric characteristics in patients with thalassaemia major

Background: Thalassaemia major is associated with characteristic findings in craniofacial bony structures and thereby may render abnormal bony orbit and subsequently distinctive ocular biometry. The purpose of the present study was to evaluate the ocular refractive and biometric characteristics in patients with thalassaemia major. Methods: This case‐controlled study comprised 94 eyes of 47 patients with thalassaemia major and 88 eyes of 44 age‐ and sex‐matched healthy control subjects. All participants had a complete ocular examination including slitlamp biomicroscopy, fundoscopy, ocular biometry, keratometry, refraction and analysis using Fourier transformation. Results: There were no significant differences in spherical equivalent (p = 0.66) and total astigmatism (p = 0.83) between groups. Mean uncorrected vision and visual acuities (logMar) were similar (p = 0.32 and p = 0.71, respectively). Compared with controls, thalassaemic patients had a shorter axial length (23.01 ± 0.12 [SEM] mm versus 23.46 ± 0.12 mm, p = 0.035), thicker crystalline lens (4.01 ± 0.11 mm versus 3.87 ± 0.1 mm, p = 0.046) and steeper average keratometry (44.02 ± 0.24 D versus 43.44 ± 0.24, p = 0.03). Fifty‐seven per cent of thalassaemic patients had against‐the‐rule astigmatism (total), while 64.6 per cent of controls showed a with‐the‐rule pattern (p < 0.05). These patterns were also found for corneal astigmatism. The magnitudes of total, corneal and lenticular astigmatism were similar among groups. Regression analysis showed significant correlation between corneal (J0 and J45) and total (J0 and J45) astigmatism. The correlations were less prominent between lenticular and total J0 and J45. The mean intraocular pressure was 14.68 ± 0.27 mmHg and 13.3 ± 0.26 mmHg in the thalassaemia and control groups, respectively (p < 0.001). Six eyes (12.8 per cent) of four patients in the thalassaemia group had posterior subcapsular cataract, while the condition had not been observed in controls (p = 0.049). Conclusions: Shorter axial length, thicker lens, steeper corneal curvature and more against‐the‐rule pattern were characteristic findings in patients with thalassaemia major.     

Silicone hydrogel mini‐scleral contact lenses in early stage after corneal collagen cross‐linking for keratoconus: a retrospective case series

Background : The aim was to the evaluate performance of a novel silicone hydrogel mini‐scleral contact lens (SHmS) for optical correction of keratoconus in the early stages after the corneal collagen cross‐linking procedure (CXL). Methods : We retrospectively analysed the visual acuity improvement and corneal adaptation in the first 10 eyes of nine patients fitted with SHmS lenses one to 3.5 months after corneal collagen cross‐linking. The lenses were designed to rest over the patients’ sclera and peri‐limbal cornea and vault the central cornea with minimal support over it. Visual acuities with manifest refraction and contact lenses, refractive and topographical values (Kmin and Kmax) were evaluated on lens dispensing and after six month of lens wearing. Ocular physiological responses were evaluated using the Institute of Eye Research (IER) grading scales. Results : SHmS fitting was performed 2.1 ± 0.97 (SD) months after collagen cross‐linking. Mean follow up was 10.9 ± 4.41 months (range six to 18 months). Mean decimal visual acuity with SHmS was 0.66 ± 0.22 (approximately 6/9 Snellen fraction, range 0.3 to 0.1) or 0.75 ± 0.14 (approximately 6/8.1, range 0.5 to 1.0), when omitting two amblyopic eyes. Nine (90 per cent) eyes were successfully fitted, that is, able to wear the lenses for 10 hours per day or longer. Mean wearing time was 11.7 hours (range six to 14) per day. No corneal neovascularisation or papillary reaction was found in all fitted eyes. Conclusions : SHmS contact lenses provide successful visual rehabilitation shortly after corneal collagen cross‐linking. This new soft contact lens design with scleral fixation and minimal apical touch was demonstrated to be safe shortly after collagen cross‐linking, as the avoidance of contact with the treated zone minimises contact lens influence on corneal recovery.     

Trends in Australian contact lens prescribing 2000

Background: This study was conducted to ascertain current modes of contact lens prescribing in Australia. Methods: One thousand questionnaires were randomly distributed to proportionate samples of optometrists in each state of Australia. The profession fits the majority of contact lenses in Australia and the sample represents 55 per cent of all optometrists. We requested details of the first 10 patients fitted with contact lenses after receipt of the questionnaire. Results: We received 224 completed questionnaires, detailing contact lens fits to 2,230 patients. The mean age of the patient group was 32.3 ± 12.9 years and 65 per cent of these were female. Sixty per cent of patients were existing wearers, the remainder being new fits. The data indicated that 94 per cent of new fits were with soft lenses, of which six per cent were for extended wear. For refits 83 per cent were soft lenses and 24 per cent were extended wear. It was clear that the lens of first choice was mid‐water‐content (52 per cent of all soft lens fits). Only nine per cent of all soft fits were for lenses which were not replaced on a planned basis. The majority of rigid lenses were prescribed using mid‐Dk materials (71 per cent). Analysis of solution prescribing indicates that multipurpose products were the most common regimens for planned replacement soft lenses. The percentage of hydrogen peroxide prescribed increased as lens replacement became less frequent. Conclusions: Non‐planned replacement lenses are now rarely prescribed to patients. Extended wear lenses and rigid lenses are prescribed more to existing contact lens wearers. The impact of multifocal lens designs on contact lens prescribing is very small, namely, five per cent of soft contact lenses and eight per cent of rigid lenses, despite 20 per cent of patients being over 45 years of age.     

An assessment of consecutively presenting orthokeratology patients in a Hong Kong based private practice

Purpose: The aim of this study was to collect objective, subjective and demographic data on consecutively presenting orthokeratology (ortho‐k) patients who attended for routine followup examination in a Hong Kong based private practice in May 2001. Method: Sixty‐nine patients who returned to the surveyed practice for follow‐up visits during the study period (May 2001) were interviewed and relevant data extracted from their files. Data collected included identification and estimation of the extent of complications encountered by ortho‐k patients and their satisfaction with the treatment. Results: Among the 61 patients who had been wearing ortho‐k lenses for at least one month, 50 patients were younger than 16 years old. Twelve children (24 per cent) had been reluctant to wear ortho‐k lenses before undergoing the treatment but, after commencement of lens wear, only one child was not very willing to wear the ortho‐k lenses. The mean pre‐ortho‐k spherical refractive error of these patients was ‐3.93 ± 2.30 D (OS only). Of the 59 patients who wore ortho‐k lenses for at least one month and who were on night therapy, 10 patients had to wear spectacles or contact lenses in the daytime due to significant residual myopia. There was no statistically significant correlation between post‐ortho‐k unaided visual acuity and pre‐ortho‐k refractive error (spherical, cylindrical or the equivalent sphere) in the 49 patients who did not need to wear any vision correction in the daytime. Of the 61 patients, four reported eye inflammation/infection during the treatment. All recovered their ocular health without any effect on their vision or corneal health. The incidence of corneal staining that required lens wear to be stopped appeared to increase with the duration of ortho‐k lens treatment. The incidence of staining was not related to refractive error, unaided visual acuity or the age of the subjects. The most common problem reported by the patients was lens binding and there were also reports of increased redness, itching, light sensitivity and secretion of mucus in the morning after opening their eyes. More than 50 per cent of the patients experienced some distance vision blur, which was worse towards the end of the day. For most patients, these problems occurred only occasionally. Higher pre‐ortho‐k spherical refractive error was related to poor near and distance vision and worse distance vision towards the end of the day. Conclusion: The majority of the patients interviewed were children who reported being ‘happy with the results of the treatment’. Night wear is the main wearing modality and in view of the increased risk of complications in overnight wear and the fact that a large number of the patients are children, the need for strict compliance with the practitioner's instructions for lens use and care cannot be overemphasised. With careful monitoring and good compliance, complications with overnight ortho‐k wear can be minimised. In view of the high incidence of lens binding, it is essential that patients and parents of young patients know the correct method to free a bound lens.     

The vascular response to long-term extended contact lens wear

The effects of long-term extended wear of soft contact lenses on human conjunctival and limbal vasculature were determined by examining 27 patients who had worn a high water content hydrogel contact lens in one eye only for an average of 62 ± 29 months (mean ± SD). The levels of general conjunctival hyperaemia (p > 0.01), limbal hyperaemia (p > 0.001), and the extent of limbal vessel penetration (p > 0.001) were found to be significantly greater in the lens-wearing eye, relative to the control eye, immediately on lens removal. The patients ceased lens wear for up to one month, and changes in the levels of vascular response were monitored during this period. General conjunctival hyperaemia and limbal hyperaemia recovered to levels observed in the non-lens-wearing eye within two and seven days after lens removal, respectively. However, limbal vessel penetration was still significantly greater in the lens-wearing eye 33 days after ceasing lens wear (p > 0.05).     

Gas-permeable scleral contact lens therapy in ocular surface disease

PURPOSE: To describe the therapeutic benefits of nonfenestrated gas-permeable scleral contact lenses in the management of patients with ocular surface disease.METHODS: The charts of 49 consecutive patients (76 eyes) with ocular surface disease whose management included the use of gas-permeable scleral contact lenses were reviewed. We also developed a questionnaire to assess the impact of lens wear on subjective aspects of activities of daily living. RESULTS: The mean age of the 49 patients was 44.6 years (range, 3 to 87 years); 31 patients were female and 18 were male. The most common indication for fitting of the lenses was Stevens-Johnson syndrome (54 [71%] of the 76 eyes). Other indications included ocular cicatricial pemphigoid, exposure keratitis, toxic epidermal necrolysis, postherpetic keratitis, congenital deficiency of meibomian glands, superior limbal keratoconjunctivitis, Sj?gren syndrome, and inflammatory corneal degeneration. The mean follow-up was 33.6 months (range, 2 to 144 months). Improvement in best-corrected visual acuity (defined as a gain of 2 or more Snellen lines) was observed in 40 (53%) of the eyes. In eight (53%) of the 15 eyes with active corneal epithelial defects at the time of lens fitting, the defects healed, whereas in the remaining seven eyes the corneal epithelial defects remained unchanged. Forty-five (92%) of the 49 patients reported improvement in their quality of life as a result of reduction of photophobia and discomfort. The mean wearing time of the gas-permeable scleral contact lenses was 13.7 hours per day (range, 4 to 18 hours). Many patients had preparatory surgical procedures before lens fitting (for example, punctal occlusion or mucous membrane grafting), and some had visual rehabilitation surgical procedures (for example, keratoplasty and/or cataract surgery) after lens fitting.CONCLUSIONS: Gas-permeable scleral contact lens wear provides an additional effective strategy in the surface management and visual rehabilitation of patients with severe ocular surface disease.     

Changes of ocular higher order aberration in on- and off-eye of rigid gas permeable contact lenses.

PURPOSE: To investigate ocular higher order aberration (HOA) changes caused by rigid gas permeable (RGP) contact lens (CL) wear. METHODS: Twenty-two eyes of 22 myopic patients and 14 eyes of 14 keratoconic patients who were fitted with an RGP CL were enrolled to examine ocular HOAs using a Hartmann-Shack wavefront sensor before and after RGP wear. Root mean square (RMS) values and Zernike coefficients in RGP-on and RGP-off eyes were compared for both myopic and keratoconic eyes, or between patient groups divided according to their prefitted total HOA value (RMS<0.33 microm or>or=0.33 microm in myopic eyes and RMS<0.46 microm or>or=0.46 microm in keratoconic eyes). All HOA values were recomputed for a 4-mm pupil for comparison purposes. RESULTS: In keratoconic eyes, RGP CL changed the direction of vertical coma from -0.185 to 0.134 microm (p=0.024). In the low HOA myopic group, total HOA increased from 0.23 to 0.35 microm (p=0.006) by RGP CL wear, mainly due to increased coma aberration from 0.0951 to 0.2146 microm (p=0.006). The direction of vertical coma changed from the inferior to superior cornea in the low HOA group (p=0.020). In the high HOA keratoconic group, total HOA decreased from 0.54 to 0.36 microm (p=0.049), and the direction of the vertical coma changed from the inferior to superior cornea (p=0.049). CONCLUSIONS: RGP CL wear may enhance or reduce HOA based on original existing ocular aberration mainly through directional changes in vertical coma.     

The influence of soft contact lens material on the corneoscleral profile

Purpose

To objectively quantify changes in corneoscleral profile, as evaluated by the limbus position and corneoscleral junction (CSJ) angle, as a consequence of wearing different soft contact lens (CL) materials.

Methods

Twenty-two healthy participants wore silicone hydrogel (SiHy, MyDay, CooperVision) and hydrogel (Hy, Biomedics 1 day extra, CooperVision) soft CLs for 8 h per lens in their left eye. In each session, corneoscleral topography was captured before and immediately after CL removal with an Eye Surface Profiler. Previously validated automatic and objective algorithms for limbal position and CSJ angle calculation were applied to 360 semi-meridians to investigate the effect of short-term CL wear on corneoscleral topography, globally and by sectors, depending on the soft CL material worn.

Results

Short-term soft CL wear significantly impacted limbal position (SiHy: 120 ± 97 μm, Hy: 128 ± 85 μm) and CSJ angle (SiHy: 0.57 ± 0.36°, Hy: 0.55 ± 0.40°); all p < 0.05. A statistically significant difference was found between the sectors with regard to limbus position and CSJ angle before CL wear that remained following lens wear (all pairwise comparisons, p < 0.001). Although individual differences were observed, there was no evidence that one material caused more substantial corneoscleral alterations.

Conclusion

Corneoscleral profile parameters were altered significantly following 8 h of soft CL wear. The observed changes in limbus position and CSJ angle support the importance of participant-material biocompatibility.     

Inflammatory status predicts contact lens discomfort under adverse environmental conditions

PurposeTo characterize and predict the clinical and tear molecular response of contact lens (CL) wearers exposed to a controlled adverse desiccating environment (CADE).MethodsObjective and subjective variables and tear cytokine levels were evaluated of monthly silicone hydrogel CL wearers pre- and post-90 min of CADE exposure. Unsupervised hierarchical agglomerative clustering based on relative change from baseline values was used to identify response profiles (clusters). A multiple logistic regression model was used to identify cluster membership predictors.ResultsForty-seven CL wearers were divided into 3 clusters having similar age (mean: 27.7 ± 7.7 years) and sex distribution. All of them showed a significant (p ≤ 0.05) increase in limbal hyperemia and staining after CADE exposure. Additionally, Cluster-1 (n = 22, 46.8%) membership was characterized by a significant (p ≤ 0.05) higher worsening of corneal and limbal staining, increased CL wear symptoms, and reduced epidermal-growth-factor and increased interleukin (IL)-4 and IL-6 tear levels. Cluster-2 (n = 22, 46.8%) showed no changes (p > 0.05) in symptoms after CADE; however, their IL-12p70, monocyte-chemoattractant-protein-1 and regulated-on-activation, normal-T-cell-expressed-and-secreted (RANTES) post-exposure tear levels significantly (p ≤ 0.05) increased. Finally, Cluster-3 (n = 3, 6.4%) mainly showed significant higher blink rate (78.1 ± 21.7) during CADE. Corneal staining and tear IL-12p70 levels were identified as Cluster-1 membership predictors.ConclusionsMost of silicone hydrogel CL wearers exposed to CADE showed a worsening of the ocular surface integrity and an upregulated tear inflammatory status. However, only half of them reported worsening of CL wear symptoms. These CL wearers were detected based on corneal integrity and tear inflammatory status. These findings can help reduce CL wear discontinuation and drop out.     

Contact lens prescribing in the Australian states and territories 2001

Background : This study was conducted to ascertain current preferences for contact lens prescribing in the Australian states and territories. Methods : One thousand questionnaires were randomly distributed to proportionate samples of optometrists in each state of Australia. We requested details of the first 10 patients fitted with contact lenses after receipt of the questionnaire. Results : One hundred and seventy‐eight completed questionnaires were returned, detailing contact lens fits to 1,611 patients. The mean age of the patient group was 32.1 $pL 13.0 yrs (65 per cent female). For Australia as a whole: 53 per cent of patients were existing wearers, the remainder were new fits; 93 per cent of new fits were with soft lenses, of which seven per cent were for extended wear. Of the refits, 89 per cent were soft lenses and 18 per cent for extended wear. The lens material of first choice was mid‐water‐content (62 per cent of all soft lens fits). Only eight per cent of all soft fits were for lenses that were not replaced on a planned basis, with two weeks being the replacement interval of choice in all states and territories. The majority of rigid lenses were prescribed using mid‐Dk materials (50 per cent). Analysis of solution prescribing indicates that multi‐purpose products were the most common regimens for planned replacement soft lenses. The percentage of hydrogen peroxide prescribed increased as lens replacement became less frequent. By state or territory: practitioners in Tasmania prescribed more extended wear than those in any other state (p = 0.007) and practitioners in Queensland prescribed more daily disposable contact lenses than those in any other state (p = 0.009). Conclusions : Non‐planned replacement lenses are now rarely prescribed to patients. Extended‐wear lenses and rigid lenses continue to be prescribed more to existing contact lens wearers than to new patients. The impact of soft multifocal lens designs on contact lens prescribing is very small, ranging from 2.6 per cent in Queensland to 4.7 per cent in Victoria, despite 20 per cent of patients being more than 45 years of age.     

Reverse geometry contact lens fitting after corneal refractive surgery

PURPOSE: To describe reverse geometry rigid gas permeable (RGP) contact lens fitting in eyes with irregular surface induced by complications after myopic corneal refractive surgery. METHODS: Reverse geometry RGP contact lenses were fit in nine eyes that underwent myopic corneal refractive surgery and experienced a reduction in best spectacle-corrected visual acuity (BSCVA) Snellen lines postoperatively. RESULTS: Comparing the BSCVA with contact lenses, 5 (55.6%) eyes improved > or = 2 lines of BSCVA, 2 (22.2%) eyes improved 1 line, and 2 (22.2%) eyes maintained the same BSCVA as the one eye with spectacles (P < .004). No eye lost lines of BSCVA. All patients reported excellent tolerance and subjective visual quality with the contact lenses. The mean time of contact lens wear was 10.44 +/- 0.88 hours per day (95% confidence interval, 9.76 to 11.12). CONCLUSIONS: Reverse geometry RGP contact lens fitting is effective in correcting surgically induced irregular surfaces with improved visual acuity and comfortable wear. These lenses may be the best choice in cases in which surgical retreatment is unfeasible or undesirable.     

Therapeutic use of Bausch & Lomb PureVision contact lenses.

PURPOSE: To evaluate the Bausch & Lomb PureVision contact lens as a continuous wear contact lens for therapeutic indications in a prospective open-ended non-randomized clinical trial. METHODS: Patients with a variety of corneal and ocular surface disease conditions presenting at the Singapore National Eye Centre who required therapeutic continuous contact lens wear were enrolled. Therapeutic indications included pain relief, corneal protection, and enhancement of corneal wound healing. Success or failure of specific treatment indications was assessed in all cases, with evaluation of lens performance and fit characteristics, and the presence of ocular complications or lens-related complications was noted. RESULTS: There were 54 patients (54 eyes), and the mean duration of continuous contact lens wear was 1.1 months. Conditions treated included post-surgical indications (n = 36) (post-keratoplasty or ocular surface transplantation, post-LASIK or PRK surgery) bullous keratopathy (n = 7), chemical burns (n = 3), epithelial abrasions or recurrent corneal erosion syndromes (n = 3), corneal perforations (n = 3), neurotrophic ulcer (n = 1), and corneal laceration (n = 1). For the indication of corneal healing (40 eyes), improved healing was noted in 38 eyes (96%), with full healing occurring in 33 eyes (83%). For pain relief (28 eyes), 27 patients (96%) had considerable or complete pain relief, and the remaining patient reported partial pain relief. For corneal protection (21 eyes), lens wear was fully protective in all cases. The lens performance and fitting characteristics surpassed any previous therapeutic lenses used by the investigators. Complications related to contact lens wear were limited to one case of a culture-negative corneal infiltrate requiring cessation of therapeutic lens wear and one case of a loosely fit lens. CONCLUSIONS: Our results show that the PureVision contact lens exhibits good safety and efficacy when utilized as a continuous wear therapeutic lens. With the theoretical advantage of increased oxygen transmissibility reducing the risk of hypoxia-related complications, this new lens may be one step closer to the ideal therapeutic contact lens. The PureVision contact lens is now our primary bandage lens of choice in our corneal, external disease, and refractive surgery services.     

Trends in Australian contact lens prescribing during the first decade of the 21st Century (2000–2009)

Purpose: The aim was to document contact lens prescribing trends in Australia between 2000 and 2009. Methods: A survey of contact lens prescribing trends was conducted each year between 2000 and 2009. Australian optometrists were asked to provide information relating to 10 consecutive contact lens fittings between January and March each year. Results: Over the 10‐year survey period, 1,462 practitioners returned survey forms representing a total of 13,721 contact lens fittings. The mean age (± SD) of lens wearers was 33.2 ± 13.6 years and 65 per cent were female. Between 2006 and 2009, rigid lens new fittings decreased from 18 to one per cent. Low water content lenses reduced from 11.5 to 3.2 per cent of soft lens fittings between 2000 and 2008. Between 2005 and 2009, toric lenses and multifocal lenses represented 26 and eight per cent, respectively, of all soft lenses fitted. Daily disposable, one‐ to two‐week replacement and monthly replacement lenses accounted for 11.6, 30.0 and 46.5 per cent of all soft lens fittings over the survey period, respectively. The proportion of new soft fittings and refittings prescribed as extended wear has generally declined throughout the past decade. Multi‐purpose lens care solutions dominate the market. Rigid lenses and monthly replacement soft lenses are predominantly worn on a full‐time basis, whereas daily disposable soft lenses are mainly worn part‐time. Conclusions: This survey indicates that technological advances, such as the development of new lens materials, manufacturing methods and lens designs, and the availability of various lens replacement options, have had a significant impact on the contact lens market during the first decade of the 21st Century.     

Long-term outcomes of donor eyes after conjunctival limbal autograft and allograft harvesting

ObjectiveTo investigate the ocular surface stability of donor eyes after conjunctival limbal autograft (CLAU) or conjunctival limbal allograft (CLAL).DesignRetrospective interventional case series.ParticipantsPatients diagnosed with limbal stem cell deficiency (LSCD) who underwent ocular surface stem cell transplantation with postoperative follow-up of at least 3 months.MethodsDonor eye data collected included preoperative and postoperative Snellen best-corrected visual acuity (BCVA), intraoperative and postoperative complications, re-epithelialization times, and ocular surface stability at the last follow-up.ResultsSixteen donor eyes of 16 patients were included, the mean age at the time of surgery was 59.3 years, and the mean follow-up period was 53 months. The most common injury etiology was chemical injury, followed by iatrogenic causes and Stevens-Johnson syndrome, then congenital aniridia. Eleven patients underwent CLAU, 3 underwent living-related CLAL, and 2 underwent CLAL combined with keratolimbal allograft. Preoperative mean donor eye BCVA was 0.22 ± 0.32 logMAR (Snellen equivalent ≈ 20/33), and mean BCVA at the last follow-up was 0.18 ± 0.24 logMAR (Snellen equivalent ≈ 20/30) (p = 0.4). All donor eyes had a stable ocular surface at the last follow-up, with no signs of iatrogenic LSCD or delayed corneal epithelial healing. There were no intraoperative or postoperative complications such as infections, persistent epithelial defects, corneal neovascularization, or chronic inflammation.ConclusionThis study provides additional evidence for the long-term safety of donor eyes when providing limbal stem cell tissue for CLAU or CLAL.