Clinical Performance of a New Bitangential Mini-scleral Lens.

SIGNIFICANCE: New bitangential mini-scleral lens designs provide a highly precise fit, follow the scleral shape, are comfortable to wear, and can correct residual astigmatism. This new scleral lens design complements the arsenal of medical contact lenses available to eye care practitioners. PURPOSE: The aim of this study was to evaluate the subjective and objective performance of a new mini-scleral lens design with a bitangential periphery. METHODS: In this observational study, data were collected for up to 15 months (median, 84 days; interquartile range, 76 days) from the left eyes of 133 patients fitted with this newly designed lens. Data were recorded during regular visits at Visser Contact Lens Practice's scleral lens clinics: diagnosis, clinical indication for scleral lenses, previous contact lens type, subjective performance, horizontal visible iris diameter, corrected distance visual acuity, and scleral lens fitting characteristics. RESULTS: The most common indication was keratoconus (45%), followed by irregular astigmatism (22%), keratoplasty (16.5%), ocular surface disease (13.5%), and other forms of irregular astigmatism (3%). The majority of patients (79%) scored comfort as either a 4 or 5 (out of 5), and 82% wore their lenses 12 hours or longer a day. Most lenses (81%) had a diameter of 16 mm (median, 16 mm; range, 15.5 to 17 mm) and were composed of Boston XO2 (46%), Menicon Z (44%), Boston XO (9%), or Boston Equalens II (1%). The median corrected distance visual acuity was 0.022 logarithm of the minimal angle of resolution (interquartile range, 0.155). The fitting characteristics revealed optimal values for centration and movement in 91% and 83%, respectively. Finally, the median stabilization axis was 50 degrees. CONCLUSIONS: New mini-scleral lenses with bitangential peripheral geometry yield satisfactory clinical results and good subjective performance and are therefore an effective option for managing patients who have irregular astigmatism or other corneal pathology.

Objective and subjective evaluation of the performance of medical contact lenses fitted using a contact lens selection algorithm.

PURPOSE: To evaluate the performance of medical contact lenses (CLs) for a wide range of clinical indications. DESIGN: Prospective cross-sectional study. METHODS: A total of 281 eyes were evaluated in 281 consecutive patients (≥18 years of age; CL use ≥3 months) who visited the contact lens service in a tertiary academic clinic for a scheduled follow-up visit. The main outcome measured were clinical indications for CL wear; CL type; change in corrected distance visual acuity (CDVA) with CL use; CL wearing duration; CL wearing time; subjective performance measured using a visual analog scale (VAS) questionnaire (score range: 0-100); and effectiveness of the lens-selection algorithm. RESULTS: Wearing CLs significantly improved CDVA compared to wearing spectacles (median change: -0.15 logMAR, range: 1.00 to -2.10; P<.001). Daily-wear CLs were worn by 77% of patients for a median of 15h/day (range: 5-18h/day), median 7 days/week (range: 1-7 days/week). High subjective scores were measured, with similar results obtained between the scleral lens and soft lens groups. The medical CL fitting was found to be generally effective (the overall satisfaction rating was ≥70 for 81% of patients). CONCLUSIONS: Fitting CLs based on the lens-selection algorithm yielded positive clinical results, including improved visual acuity, satisfactory wearing time, and high overall subjective performance. Moreover, subjective performance was similar between users of scleral lenses and users of soft lenses. These results underscore the importance of prescribing scleral lenses and the need for tertiary eye clinics to offer patients a variety of CL types.

Scleral lens influence on corneal curvature and pachymetry in keratoconus patients.

OBJECTIVES: To investigate the influence of full scleral lenses on corneal curvature and pachymetry in keratoconus patients. METHODS: In this intervention study, 20 eyes of 14 patients were measured by Scheimpflug imaging (Pentacam HR, Oculus) at two time points: directly and ≥1 week after scleral lens removal. Steep, flat and maximal keratometry (K(steep), K(flat) and K(max)) and optical pachymetry were analyzed. A generalized estimating equation analysis was performed to correct for paired eyes. RESULTS: Directly after scleral lens removal, all three curvature parameters were significantly flatter compared to ≥1 week after scleral lens removal. Average K(steep) was 0.7 diopter (D) lower (P<0.001), average K(flat) was 0.5D lower (P=0.037) and average K(max) was 1.1D lower (P<0.001). Directly after scleral lens removal, average optical pachymetry was ±2.5% higher (P<0.001) compared to ≥1 week after scleral lens removal. CONCLUSIONS: Although scleral lenses do not mechanically touch the cornea, curvature and pachymetry seem to be influenced by scleral lens wear in keratoconus patients. The duration of these changes remain unclear.

Scleral lens tolerance after corneal cross-linking for keratoconus.

PURPOSE: Subjective and objective evaluation of scleral lens tolerance and fitting before and after corneal cross-linking (CXL) for progressive keratoconus. METHODS: In this prospective cohort, evaluations were made of 18 unilateral eyes in patients who underwent CXL and had been wearing scleral lenses before the procedure. All the patients gave informed consent; they were able to cooperate with the study, were eligible for CXL, had been wearing well-fitting scleral lenses for at least 3 months, and had no other active ocular disease. Data were collected before and 1 year after CXL. Outcome measures were changes in clinical and subjective scleral lens performance. The following components were studied: scleral lens corrected distance visual acuity, scleral lens specifications, scleral lens fit, wearing time, and subjective measures on visual analogue scale questionnaires (1 to 100 mm). RESULTS: There was no significant change in scleral lens corrected distance visual acuity (p = 0.632). Sixty-one percent of eyes needed a scleral lens fit and/or power change. Wearing time (median, 16 hours per day) and subjective tolerance were found to be stable. CONCLUSIONS: Scleral lens tolerance after CXL appeared to be stable.

Medical applications and outcomes of bitangential scleral lenses.

PURPOSE: To evaluate the clinical results of a new scleral lens design with a bitangential (nonrotationally symmetrical) periphery. METHODS: All the necessary data were obtained during the 1-year study period. The bitangential scleral lenses were fitted and monitored according to a standardized fitting methodology. They were cut by precise submicron lathing from high-oxygen-permeable materials (including 10 scleral lenses from Menicon Z material). Subjective performance, visual acuity, and scleral lens-fitting characteristics were recorded after a median of 9.4 weeks (range, 3 weeks to 1 year). RESULTS: Diagnoses in the 213 eyes (in 144 patients) were keratoconus (n = 121 eyes; 56.8%), ocular surface diseases (n = 31 eyes; 14.6%), penetrating keratoplasty (n = 29 eyes; 13.6%), and other forms of irregular astigmatism (n = 28 eyes; 13.1%). Many patients (164 lenses; 77.0%) gave high ratings for comfort. The most common diameter was 20.0 mm (162 lenses; 76.1%) (range, 18.5 to 21.5 mm). Median decimal best-corrected visual acuity with the bitangential scleral lenses was 0.8 (equivalent to Snellen 20/25) (range, 0 to 1.5). Most bitangential scleral lenses showed good fitting characteristics: optimal values were seen for lens movement (208 lenses; 97.7%) and lens position (208 lenses; 97.7%). Median central corneal clearance was 0.2 mm; clearances differed in the four peripheral directions. The median stabilization axis was 140 degrees (range, 0 to 180 degrees) in the right eyes and 60 degrees (range, 0 to 180 degrees) in the left eyes. CONCLUSIONS: The bitangential scleral lens-fitting and performance characteristics were clear and effective for the health professional and the patient. The high-oxygen-permeable material Menicon Z may, in theory, be of benefit to corneas with a high oxygen demand.

Modern scleral lenses part I: clinical features.

PURPOSE: To evaluate the indications for modern scleral lenses and their clinical performance in patients who were fitted with scleral lenses at the authors' practices. METHODS: In this cross-sectional survey, all the necessary data were obtained at the first follow-up visit during the 5-month study period. There were four types of scleral lenses: spherical, front-surface toric, back-surface toric, and bitoric. The preformed scleral lens fitting technique developed at Visser Contact Lens Practice was used in all patients. The lenses were cut by precise Sub Micron Lathing from a Boston Equalens II blank at Procornea. Visual acuity and slitlamp findings were recorded. A specially designed classification for scleral lens fitting was used to investigate clinical performance. RESULTS: The largest proportion of the 178 patients (284 eyes) were diagnosed with keratoconus (143 [50.4%] eyes) followed by postpenetrating keratoplasty (56 [19.7%] eyes). The remaining diagnoses were irregular astigmatism, keratitis sicca, corneal dystrophy, and multiple diagnoses. The ratio of spherical to back-surface toric designs was 1:1.1. Clinical examination showed sharp increases in visual acuity (median increase, 0.45) and safe physiologic responses of the anterior eye. All the patients could continue to wear scleral lenses, with 79.2% with the same lens parameters. CONCLUSIONS: Several types of corneal abnormality were managed successfully with modern scleral lenses. The main indication was optical correction of an irregular corneal surface. Satisfactory clinical performance meant that all the patients could continue to wear their scleral lenses.

Modern scleral lenses part II: patient satisfaction.

PURPOSE: To evaluate the subjective performance of modern scleral lenses in patients of the clinics of Visser Contact Lens Practice. METHODS: In this cross-sectional survey, all the necessary data were collected at the first follow-up visit during the 5-month study period. In accordance with the preformed fitting technique developed at Visser Contact Lens Practice, four types of scleral lenses were used: spherical, front-surface toric, back-surface toric, and bitoric. Subjective performance was investigated during an interview that included the use of a five-point Likert scale and by means of a questionnaire supplemented by a 100-mm visual analog scale (VAS). RESULTS: The interview and questionnaire showed high scores for patient satisfaction with the current scleral lens in the 178 patients (284 eyes) (median score, 4; range Likert scale, 1-5; median score, >or=75; range VAS, 1-100). Significant increases in scores were seen with the current scleral lens compared to the former correction: 78.9% for comfort, 78.2% for visual quality, and 87.7% for overall satisfaction (n=284 eyes) (P<0.001). In the 99 eyes that switched from back-surface spherical to back-surface toric designs, the following significant increases were seen: 61.6%, 37.4%, and 65.7%, respectively (P<0.001). CONCLUSIONS.: High patient satisfaction was seen with all the modern scleral lens designs in the management of several forms of corneal abnormality. The interview showed differences in comfort, visual quality, and overall satisfaction in favor of the back-surface toric designs compared to the back-surface spherical designs.

Advantages of toric scleral lenses.

PURPOSE: The purpose of this study was to investigate whether back surface toric scleral lenses stabilized (i.e., returned to their original position after rotation) and how long the return times were. Return time was studied in relation with actual wearing time and comfort; moreover, the performance of the spherical scleral lens was compared with the toric scleral lens design. METHODS: Toric scleral lenses were rotated clockwise and counterclockwise over 60 degrees. Return times and the actual wearing time were recorded. Results were transformed into nasal and temporal return times for symmetry reasons. The present and former types of correction were compared for comfort (ranging from 0: very poor to 10: excellent) and regular wearing time. All the subjects attended regular follow-up visits. RESULTS: Forty-three subjects (43 lenses) entered the study. All the lenses returned to the original position within a median of 4 seconds after nasal rotation and 6 seconds after temporal rotation. A significant correlation was found between mean return times and actual wearing time (r = 0.63). Significant increases in median comfort (from 6-8) and median wearing time (from 15-16 hours) were demonstrated when the toric scleral lens designs were compared with the former type of correction (both p < 0.001). Median comfort and median wearing time also increased significantly after changing from spherical scleral lenses to the toric design (from 7-8 and from 14-16 hours, both p < 0.001, n = 27 eyes). CONCLUSIONS: Toric scleral lenses returned rapidly to their original position after rotation. The flattest meridian of the toric scleral lenses stabilized symmetrically. Patient interviews demonstrated differences in comfort and wearing time in favor of the toric design.