The effect of different thickness scleral lens on corneal parameters in eyes with keratoconus

Purpose: To investigate the impact of different?thickness scleral lenses (SLs) on corneal thickness, curvature, and fluid reservoir thickness in keratoconic eyes. Methods: Schiempflug imaging and AS?OCT was captured before and immediately following 6 h of SL wear. Different?thickness lenses were used while keeping the other parameters the same. The timing of the measurement for day 1 and day 2 was matched to allow for the control of the confounding influence of diurnal variation. Results: Immediately after 6 h of lens wear, no statistically significant difference (P > 0.05) was noted in corneal edema in any region and quadrants between thin? and thick?lens wearers. The calculated percentage of corneal edema was also within the range of overnight closed eye physiological swelling. Pentacam measured higher central corneal thickness compared to AS?OCT in both baselines and after 6 h of lens wear. The current investigation reported minimal but not statistically significant (P > 0.05) flattening in anterior and steepening in posterior curvature parameters in both thin and thick SLs. The mean reduction in the fluid reservoir thickness was 80.00 ± 3.99 and 79.36 ± 3.84 microns after 6 h of thin? and thick?lens wear, respectively, which was not statistically significant (P > 0.05). A statistically significant positive correlation (r = 0.67, P = 0.02) was found between lens thickness and change in anterior steep k with thick?lens wear. Conclusion: Central lens thickness of 200–400 ?m did not cause any significant change in corneal curvature and fluid reservoir thickness and did not induce clinically significant corneal edema after short?term SL wear.

Reabilitação visual com lentes de contato após transplante de córnea / Visual reabilitation with contact lenses after corneal keratoplasty

Resumo A adaptação de lentes de contato após o transplante de córnea tem sido considerada um desafio na reabilitação visual. Atualmente existe a possibilidade de adaptação de lentes de contato de vários tamanhos, diversos desenhos e com diferentes espessuras e materiais, como por exemplo lentes gelatinosas, lentes corneanas rígidas gás-permeáveis, lentes córneo-esclerais, mini esclerais e esclerais. O objetivo deste estudo foi apresentar uma revisão da literatura atual que possa exemplificar a utilização de alguns dos diferentes tipos de lentes de contato que possam ser usadas após o transplante de córnea. Foi realizada uma revisão integrativa da literatura médica na língua inglesa, utilizando como base de dados para a pesquisa, Pubmed e Mendeley. Como critério de inclusão, foi estabelecido a relevância do artigo de acordo com a experiência da equipe. Foram selecionados 26 artigos, com ano de publicação entre 2001 e 2018. Dentre os artigos selecionados, cinco possuem como principal assunto o transplante de córnea, nove artigos sobre lentes de contato em geral, e 12 artigos sobre lentes de contato esclerais ou mini esclerais. Devido a maior transmissibilidade de oxigênio para a córnea, o uso das lentes corneanas rígidas gás-permeáveis mostrou-se mais seguro e com probabilidade de uso por um período maior de tempo.

Abstract Contact lens fitting after corneal transplantation has been considered a challenge in visual rehabilitation. There is currently the possibility of adapting contact lenses of various sizes, various designs and with different thicknesses and materials, such as gelatinous lenses, gas-permeable rigid corneal lenses, corneal-scleral lenses, mini-scleral and scleral lenses. The objective of this study was to present a review of current literature that may exemplify the use of some of the different types of contact lenses that can be used after corneal transplantation. An integrative review of the medical literature in the English language, using as a database for the research, Pubmed and Mendeley. Twenty six articles were selected, with year of publication between 2001 and 2018, as inclusion criterion, the relevance of articles according to the authors' experience was used. Five articles were selected that have as main subject corneal transplantation, nine articles on contact lenses in general, and 12 articles on scleral or mini scleral contact lenses. Due to the greater transmissibility of oxygen to the cornea, the use of rigid gas-permeable corneal lenses was shown to be safer and more likely to be used for a longer period of time.

Scleral Lens Application for Preventing Corneal Edema During Vitrectomy

PURPOSE: To analyze the effect of scleral lens application for preventing corneal edema during vitrectomy on postoperative corneal status using anterior segment OCT (RTVue 100, Optovue, Fremont, CA, USA). METHODS: The medical records of 42 eyes (42 patients) who underwent total vitrectomy with no appreciable corneal disease between November 2014 and June 2015 were retrospectively reviewed. Evaluations were performed at 1 day, 1 week, and 1 month after total vitrectomy. Corneal status was noted at every follow-up visit using anterior segment OCT. An analysis was performed to define the changes in corneal status in association with scleral lens application during the surgery. RESULTS: 18 of 42 eyes were treated with a scleral lens during total vitrectomy. The corneal thickness increased after vitrectomy in all cases. The mean corneal thickness increment was 23.9 ± 9.7 µm in the scleral lens group and 43.0 ± 19.5 µm in the non-scleral lens group at 1 day after vitrectomy (p < 0.001). At 1 week after vitrectomy, the mean corneal thickness increment was 8.1 ± 7.2 µm in the scleral lens group and 32.3 ± 19.2 µm in the non-scleral lens group (p < 0.001). The difference in superficial punctate keratitis grade between the two groups was not statistically significant. CONCLUSION: Scleral lens application during vitrectomy seems to prevent postoperative corneal edema. More cases and a longer period of study is needed to draw definitive conclusions.

Fitting the Miniscleral Contact Lens in Patients with Corneal Abnormalities

PURPOSE: To evaluate the clinical results of fitting the miniscleral contact lens (MSD; Happy Vision Corp., Anyang, Korea) in patients with corneal abnormalities. METHODS: Thirty-eight patients (56 eyes) fitted with MSD lenses were recruited for this study. Clinical indication, visual acuity, degree of comfort, mean wearing time, parameters of the finally prescribed lenses, number of fittings with trial lenses, success rate with the first prescribed lens, and adverse events were evaluated. RESULTS: Forty-two (75%) of 56 eyes were enrolled in this study due to keratoconus. Other conditions included Stevens-Johnson syndrome (6 eyes, 11%), high postkeratoplasty astigmatism (3 eyes, 5%), corneal scarring (3 eyes, 5%), and ectasia after laser in situ keratomileusis (LASIK; 2 eyes, 4%). The mean log MAR visual acuity improved from 1.01 ± 0.64 to 0.13 ± 0.19 after wearing lenses (p= 0.0001). In 53 eyes (94.6%), patients reported the miniscleral contact lenses to be comfortable, and the mean daily wear time was 12.9 ± 2.5 hours. The mean sagittal depth of finally prescribed lenses was 4.67 ± 0.37 mm (3.7-5.4). An average of 3.3 ± 1.5 (1-7) trials were needed for the trial fitting, and the average number of re-prescriptions to achieve the optimal fitting was 1.5 ± 0.48 (1-3). One patient discontinued the lenses after 3 months due to discomfort. CONCLUSIONS: Miniscleral contact lenses are a good alternative for patients with corneal abnormalities and result in both successful visual outcome and comfort.

Contact lens in keratoconus.

Contact lenses are required for the visual improvement in patients with keratoconus. Various contact lens options, such as rigid gas permeable (RGP) lenses, soft and soft toric lenses, piggy back contact lenses (PBCL), hybrid lenses and scleral lenses are availble. This article discusses about selection of a lens depending on the type of keratoconus and the fitting philosophies of various contact lenses including the starting trial lens. A Medline search was carried out for articles in the English language with the keywords keratoconus and various contact lenses such as Rose k lens, RGP lens, hybrid lens, scleral lens and PBCL.