Influence of Specialty Contact Lens Wear on Posterior Corneal Tomography in Keratoconus Subjects.

OBJECTIVE: To evaluate the effect of specialty contact lens (CL) wear on posterior corneal tomography in keratoconus subjects. METHODS: Patients with keratoconus who were wearing specialty CL were included in this retrospective cohort study. Tomographic parameters were evaluated with Scheimpflug imaging (Pentacam HR) before lens fitting and immediately after removal of CLs worn habitually for a period of several months. Subjects were divided into groups, according to type of lens (corneal, scleral, and hybrid) and keratoconus severity based on Belin/Ambrosio D (BAD-D) score, for further analysis. RESULTS: Thirty-four eyes of 34 subjects diagnosed with keratoconus were included. Mean duration of habitual CL wear was 7.0±0.3 months. For the entire cohort, a small increase in flat keratometric reading at the anterior corneal surface (K1F; P =0.032) and at the posterior surface (K1B; P =0.041) was found. In the corneal CL group (10 eyes; 29.4%), flattening of the anterior corneal curvature was detected (K max ; P =0.015). An increase in K1B value was seen in the scleral CL group (15 eyes; 44.1%) ( P =0.03). Combined topometric indices showed a small but significant difference in the entire cohort ( P <0.05) and in the subgroups of corneal CL wear and of moderate keratoconus (BAD-D score≥7). CONCLUSION: Various types of specialty CLs exert a differential influence on corneal parameters. A small steepening of keratometry at the posterior surface (K1B) was observed in the scleral lens group. Although corneal lens wear flattens the anterior cornea (K max ), it does not significantly alter the posterior corneal surface.

Anterior eye surface changes following miniscleral contact lens wear.

PURPOSE: To quantify the effect of short-term miniscleral contact lens wear on the anterior eye surface of healthy eyes, including cornea, corneo-scleral junction and sclero-conjuctival area. METHODS: Twelve healthy subjects (29.9 ±â€¯5.7 years) wore a highly gas-permeable miniscleral contact lens of 16.5 mm diameter during a 5-hour period. Corneo-scleral height profilometry was captured before, immediately following lens removal and 3 h after lens removal. Topography based corneo-scleral limbal radius estimates were derived from height measurements. In addition, elevation differences in corneal and scleral region were calculated with custom-written software. Sclero-conjuctival flattening within different sectors was analysed. RESULTS: Short-term miniscleral lens wear significantly modifies the anterior eye surface. Significant limbal radius increment (mean ±â€¯standard deviation) of 146 ±â€¯80 µm, (p = 0.004) and flattening of -122 ±â€¯90 µm in the sclero-conjuctival area, (p << 0.001) were observed immediately following lens removal. These changes did not recede to baseline levels 3 h after lens removal. The greatest anterior eye surface flattening was observed in the superior sector. No statistically significant corneal shape change was observed immediately following lens removal or during the recovery period. CONCLUSIONS: Short-term miniscleral contact lens wear in healthy eyes does not produce significant corneal shape changes measured with profilometry but alters sclero-conjuctival topography. In addition, sclero-conjuctival flattening was not uniformly distributed across the anterior eye.

Scleral asymmetry as a potential predictor for scleral lens compression.

PURPOSE: To identify the position and magnitude of lens compression due to short-term miniscleral contact lens wear, as well as evaluating the usefulness of scleral asymmetry as a predictor for scleral lens decentered compression. METHODS: Fourteen healthy subjects (mean ± S.D.: 29.2 ± 6.0 years) wore a highly gas-permeable spherical haptic miniscleral contact lens during a 5-h period. Corneo-scleral height Fourier profilometry was captured using an Eye Surface Profiler (www.eaglet-eye.com) before and immediately after lens removal. Scleral asymmetry, lens compression location and magnitude were processed using custom-made algorithms, both globally and for scleral quadrants. RESULTS: Miniscleral contact lenses do not set uniformly on the ocular surface, with the largest decentration seen along the horizontal meridian. The greatest flexural stress exerted by the lens on the ocular surface occurs at the point coinciding with the inner diameter landing point of the lens and not with its overall diameter. Scleral asymmetry was significantly correlated with compression location (R = 0.71, p = 0.002) and compression magnitude (R = 0.81, p < 0.001), showing its potential as compression predictor. CONCLUSION: Larger amounts of scleral asymmetry will lead to more decentration of spherical haptic scleral lenses. Objective and accurate methods, like the one presented here, could help the practitioner prevent cases of scleral blanching or discomfort due to an excessive compression by the lens.

A Case of Late Spontaneous Post-Radial Keratotomy Corneal Perforation Managed With Specialty Lenses.

PURPOSE: To describe a case of spontaneous wound dehiscence 29 years after radial keratotomy (RK) and to illustrate how specialty contact lenses were used for tectonic support and optic correction. SETTING: Tertiary referral center for corneal pathology. DESIGN: Case report. RESULTS: In November 2014, a 62-year-old woman presented to the emergency department with a spontaneous corneal perforation in her left eye. Her ocular history was significant only for uncomplicated RK surgery performed in 1985 to correct myopia (-5.50 D) in both eyes. At the slit-lamp pronounced, bullous edema was seen in the inferotemporal quadrant of the left cornea with internal opening of the 3.30- and 5-o'clock positions incisions and severe localized thinning and aqueous leakage at the 5-o'clock position incision. There was no history of trauma. A conservative approach was adopted: application of a standard bandage lens was effective in tamponading the leakage, allowing the anterior chamber to reform; a custom-made soft lens was worn for tectonic support over a period of 4 months. Finally, visual acuity was restored to 20/20-by fitting a scleral lens. CONCLUSION: Spontaneous corneal perforation is a rare but more dramatic long-term complication after RK. The pivotal role of appropriately fitted soft bandage lenses in the conservative management of this type of complex perforation is highlighted. For optical correction, a scleral lens was fitted with excellent visual result, illustrating the added value of specialty contact lenses as an alternative to surgery in the management of postrefractive corneas.

Scleral Lenses Reduce the Need for Corneal Transplants in Severe Keratoconus.

PURPOSE: To investigate the success and failure rates of scleral lens correction in severe keratoconus. DESIGN: Retrospective case series. METHODS: Study population comprised patients with keratoconus who attended the keratoconus clinic at the Antwerp University Hospital, Belgium, between January 1, 2010, and December 31, 2014. The included eyes had maximal keratometry values ≥ 70 diopters, as measured using the sagittal curvature map that was obtained by Scheimpflug tomography. The exclusion criteria included amblyopia, mental retardation, and concomitant ocular disease that limited their visual potential. RESULTS: Scleral lens fitting was proposed for the 75 eyes included in the study. Eight eyes underwent transplant surgery because of insufficient visual acuity with the lenses, lens intolerance, and issues with handling the lenses. Twelve eyes did not have lenses fitted because of good visual acuity in the other eye or a contraindication for lens wear. Three eyes were successfully fitted with corneal or hybrid lens wear. Scleral lenses were prescribed in 51 of 75 eyes. The mean gain in visual acuity (lens vs spectacle-corrected visual acuity) was 0.54 ± 0.18 (decimal fraction, Snellen eye chart). Seven eyes were lost to follow-up, 4 eyes abandoned wearing the scleral lens because of an inability to handle the lenses, and 40 eyes wore the lenses at their last follow-up visit, with a mean follow-up interval of 30.15 ± 12.83 months. CONCLUSIONS: Forty of the 51 eyes with severe keratoconus that would otherwise have undergone transplant surgery were successfully treated with long-term scleral lens wear. In this way, the indication for keratoplasty was more than halved in our keratoconus population.