New developments in the management of persistent corneal epithelial defects

A persistent epithelial defect (PED) is a corneal epithelial defect that failed to heal after 2weeks. It is a condition that carries much morbidity, and our understanding of PED remains poor, with current treatment methods often having unsatisfactory outcomes. With PEDs becoming more prevalent, more efforts are required to establish reliable treatment modalities. Our reviews describe the causes of PEDs and the different approaches developed to manage them, as well as their associated limitations. Emphasis is placed on understanding various advances in the development of new treatment modalities. We have also described a case of a woman with a background of graft-versus-host disease on long-term topical corticosteroids who developed complicated PED involving both eyes. The current approach to managing PEDs generally involves exclusion of an active infection, followed by treatment modalities that aim to encourage corneal epithelial healing. Success rates, however, remain far from desirable, as treatment remains challenging due to multiple underlying etiologies. In summary, advances in the development of new therapies may be able to facilitate progress in the understanding and treatment of PED.

Assessment of long-term visual outcomes in aphakic children wearing scleral contact lenses

BACKGROUND

Timely management of aphakic children is critical for the rehabilitation of adequate visual gain. This study aims to evaluate the long-term efficacy of scleral contact lenses in terms of visual outcomes, complications, and compliance in aphakic children.

METHODS

Retrospective data review of children with congenital or acquired cataract, or subluxated crystalline lenses, who underwent lensectomy from 2004 to 2018 and who used scleral contact lenses for refractive correction. Collected data from the follow up period included recorded aphakic refraction and visual acuity, complications following scleral contact lens wear documented in the clinic and ophthalmic emergency room and compliance to lens wear according to parental feedback on every visit in the clinic.

RESULTS

76% of cases, with final best corrected visual acuity (BCVA) of 20/40 or better achieved in seventeen eyes (34%). The rate of amblyopia was 50%. Strabismus developed in 56% of children, and those had less favourable visual outcomes (0.43 ± 0.4 LogMAR without strabismus and 0.8 ± 0.5 LogMAR with strabismus, p = 0.015). No corneal infections were documented during the follow up. Main adverse effect on the ocular surface was superficial punctate keratopathy (n = 16). Compliance was good in 48 children (96%)- except for two cases, the scleral lenses were tolerated well by all children.

CONCLUSION

Scleral contact lenses are an effective means of visual rehabilitation in aphakic children after lensectomy and may be used long-term with good compliance of wear, excellent visual outcomes, and tolerable adverse events.

Microbial Keratitis Associated With Penetrating Keratoplasty and Scleral Lens Wear: A Case Series

OBJECTIVES

To report on microbial keratitis (MK) in three scleral lens (SL) wearers who had undergone penetrating keratoplasty (PKP).

METHODS

This retrospective case series describes 3 cases of MK in patients who wore SLs after PKP.

RESULTS

All three patients wore SLs for visual rehabilitation for corneal irregularity induced by PKP; all three also had concurrent ocular surface disease (keratoconjunctivitis sicca and corneal exposure). Cultures identified the causative organism in two patients, and septated hyphae suggestive of fungal infection were identified in tissue removed during therapeutic PKP in the third patient. All three patients were receiving either topical or systemic immunosuppressive therapy before the infection developed.

CONCLUSIONS

Scleral lenses are often used to manage complex ocular disease, which can make it difficult to determine the precise cause of complications that arise after wearing the lenses. Multiple factors, including SL wear, may have contributed to the initial development of MK in the three patients in this case series. Patients who wear SLs after PKP should be monitored closely.

CLEAR - Medical use of contact lenses

The medical use of contact lenses is a solution for many complex ocular conditions, including high refractive error, irregular astigmatism, primary and secondary corneal ectasia, disfiguring disease, and ocular surface disease. The development of highly oxygen permeable soft and rigid materials has extended the suitability of contact lenses for such applications. There is consistent evidence that bandage soft contact lenses, particularly silicone hydrogel lenses, improve epithelial healing and reduce pain in persistent epithelial defects, after trauma or surgery, and in corneal dystrophies. Drug delivery applications of contact lens hold promise for improving topical therapy. Modern scleral lens practice has achieved great success for both visual rehabilitation and therapeutic applications, including those requiring retention of a tear reservoir or protection from an adverse environment. This report offers a practical and relevant summary of the current evidence for the medical use of contact lenses for all eye care professionals including optometrists, ophthalmologists, opticians, and orthoptists. Topics covered include indications for use in both acute and chronic conditions, lens selection, patient selection, wear and care regimens, and recommended aftercare schedules. Prevention, presentation, and management of complications of medical use are reviewed.

Scleral Lens Use in Neurotrophic Keratopathy: A Review of Current Concepts and Practice

OBJECTIVE

Neurotrophic keratopathy (NK) is a rare corneal condition characterized by epitheliopathy, which is associated with reduced or absent corneal sensation. The main goal of treatment of this condition is the preservation of ocular surface integrity. Contact lenses provide a nonsurgical and reversible option to provide the necessary corneal protection. The purpose of this review was to summarize the available literature regarding the use of contact lenses in the management of NK, with particular emphasis on the use of scleral lenses.

METHODS

Literature related to both soft and scleral contact lens use as treatment options for NK was reviewed.

RESULTS

As of yet, randomized clinical trials have compared neither the efficacy of contact lens therapy for NK to other therapeutic alternatives nor outcomes of therapy with different contact lens modalities. However, clinical case reports and limited case series have suggested that scleral lenses may be a safe and effective treatment option for NK at any stage of the disease, preserving epithelial integrity and even improving visual function in patients with this condition.

CONCLUSIONS

Scleral lenses may be effective in reducing the need for surgical intervention and improving the quality of life in patients with NK.

Current perspectives in the management of keratoconus with contact lenses

Our aim is to review current and significant articles on contact lens wear in keratoconus patients. A comprehensive literature search of PubMed was performed for the following topics on contact lens wear in keratoconus patients: (1) characteristics of contact lens wearers, (2) safety and efficacy, (3) complications, (4) fitting techniques, (5) contact lens wear after procedures/surgeries, (6) patient satisfaction. A total of 104 studies were finally selected and reviewed. Gas permeable (GP) lens wear provided significantly better vision than glasses. Special cone design lenses had better patient comfort levels though there was no difference in best corrected visual acuity among the GP lenses. Soft lenses showed good efficacy for the treatment of mild-to-moderate keratoconus with newer designs improving visual performance such as customised hydrogel and novel pinhole lenses. Scleral and hybrid lenses provide good visual acuity and comfort for keratoconic patients previously intolerant to RGP lenses. RGP lens wear post-cross linking (CXL) is relatively well-tolerated. Contact lenses may still be required post intrastromal corneal ring procedures and post keratoplasty. Scheimpflug imaging and anterior segment optical coherent tomography (ASOCT) are useful in contact lens fitting. Computerized contact lens fitting techniques could reduce the chair time of lens fitting as well as improve comfort and visual performance. Contact lenses play an important role in the visual rehabilitation of keratoconus patients. New contact lens designs and materials have significantly expanded the available fitting options for keratoconus patients. Imaging technology can be utilized to guide contact lens fitting.

Indications for Wear, Visual Outcomes, and Complications of Custom Imprint 3D Scanned Scleral Contact Lens Use

PURPOSE

To report indications for wear, visual outcomes, and complications of EyePrintPRO (EPP) scleral contact lens (SCL) use.

METHODS

A retrospective review identified all patients fitted with this device between December 2013 and March 2018. Baseline demographics, wear indication, and contact lens history were determined. Habitual-corrected visual acuity was measured at baseline and follow-up. Adverse wear symptoms and signs, reprinting, and device cessation were tracked.

RESULTS

Ninety-five eyes from 69 patients were followed for a median of 12.1 months (interquartile range 4.4-19.6). Indications for wear included vision improvement and/or ocular surface stabilization in the setting of irregular corneal shape (n = 68 eyes, 72%), ocular surface disease (n = 17, 18%), exposure keratopathy (n = 7, 7%), neurotrophic keratitis (n = 5, 5%), and extracorneal topographical abnormalities preventing noncustom lens fitting such as glaucoma drainage devices (n = 8, 8%). Median habitual-corrected visual acuity improved from 0.67 to 0.08 (P = 0.0003). One-third of eyes (33.1%) developed adverse wear symptoms. Fifteen of 95 eyes (16%) developed adverse wear signs. Device cessation occurred in 10 eyes (10.5%) and reprinting occurred in 14 eyes (14.7%) unrelated to prior lens wear or indication (P = 0.67 and 0.15, respectively). In eyes that previously failed SCLs (n = 56), 12 eyes required reprinting and 49 eyes continued use.

CONCLUSIONS

Indications for EPP wear include irregular corneal shape, ocular surface disease, and extracorneal topographic abnormalities. Visual acuity improves with the use of EPP. Clinicians and patients should be aware of potential adverse wear symptoms/signs and device cessation that may occur with EPP use. EPP is a viable salvage therapy in eyes that previously failed SCLs.

Multicenter review of impression-based scleral devices

OBJECTIVE

To describe outcomes using impression based-scleral devices for the management of anterior segment disease.

METHODS

Retrospective chart review identified all patients who were fitted with impression-based scleral devices between January 1, 2013 and June 30, 2019 at three specialty contact lens practices. Patient demographic data, indication for device use, visual and physiological outcomes, as well as details of the fitting process and survival of device use were determined.

RESULTS

Forty-four patients (70 eyes) were included in the study. Primary indications for device use included corneal irregularity (28 patients, 44 eyes) and ocular surface disease (16 patients, 26 eyes). Fifty-four percent of patients had more than one ocular surface condition, and 39 % of patients had undergone at least one anterior segment surgical procedure. Twenty-nine patients had unsuccessfully attempted to wear standard scleral lenses prior to being fit with impression-based devices. Visual acuity improved significantly with impression-based devices compared to habitual correction (p < 0.001). Completion of the fitting process (including visit to acquire the impression and post-fitting assessments) required an average of 4 [1.5] visits.Ideal haptic alignment was achieved with 74 % and complete limbal clearance was achieved in 83 % of fits. Device use was discontinued due to complications in two eyes.

CONCLUSION

Patients with complex eye disease who are unable to successfully wear standard scleral lenses successfully may achieve visual and therapeutic success with impression-based devices.

Safety and Efficacy of Scleral Lenses for Keratoconus

SIGNIFICANCE

This study affirms the long-term safety and efficacy of scleral contact lens use in patients with keratoconus.

PURPOSE

This study aimed to evaluate the safety and efficacy of contemporary scleral contact lenses in the visual rehabilitation of the keratoconic population.

METHODS

A retrospective study of keratoconic subjects examined between 2013 and 2018 was conducted. Subjects were included regardless of age, sex, pre-existing morbidity, or scleral lens design. Only eyes fit successfully with scleral contact lenses for ≥1 year were included. Exclusion criteria were prior corneal surgery, dystrophy, degeneration, and trauma.

RESULTS

A total of 157 eyes of 86 subjects met the study criteria. The mean Keratoconus Severity Score at initial fitting was 3.6 ± 1.0. Lenses were gas-permeable and nonfenestrated, with a mean overall diameter of 15.8 ± 0.6 mm and 70.1% toric scleral periphery. Physiological adverse events occurred in 9.6% of eyes, including microbial keratitis (0.6%), phlyctenulosis (0.6%), corneal abrasion (1.3%), contact lens–induced acute red eye (1.3%), corneal infiltrative events (1.3%), pingueculitis (1.3%), and hydrops (3.2%). Lens-related adverse events were documented in 55.4% of eyes. Adverse events related to surface issues included poor wetting in 1.9%, handling in 3.8%, reservoir fogging in 7.0%, lens intolerance in 7.6%, deposit in 8.9%, and broken lenses in 26.1% of eyes. The most common management strategies involved refits (54.0% of interventions), patient reeducation (29.5%), medical treatment (5.5%), surgical referral (6.8%), adjustment to wear time (2.5%), surface treatment (1.2%), and lens replacement (0.6%). Best-corrected distance logMAR visual acuity improved significantly from a mean of 0.50 in spectacles to a mean of 0.08 in scleral lenses (P < .0001). During the study period, 14.6% of eyes lost best-corrected scleral lens visual acuity, all from keratoconus progression.

CONCLUSIONS

Consistent with other groups, our study demonstrates excellent safety and efficacy of scleral contact lenses in subjects with keratoconus.

Scleral lens wear: Measuring inflammation in the fluid reservoir

PURPOSE

To measure inflammatory mediators in the scleral lens fluid reservoir (FR) in healthy eyes and to compare them to basal tear samples after 8-hs (8h) and 4-days (4d) of scleral lens (SL) wear.

METHODS

Fifteen normal, habitual soft contact lens wearers were fitted with 14.8- or 15.4-mm SLs (Zenlens, Alden Optical, USA). Basal ocular surface tears and FR samples were collected after 8h and 4d of daily SL wear. Levels of interleukin (IL) -4 and -8, matrix metalloproteinase (MMP)-7, -9, and -10, and tissue inhibitor of MMPs (TIMPs) 1-4 were measured in all samples using Luminex assays. Visual acuity, corneal and conjunctival staining, and comfort assessments were completed at the baseline, 8h and 4d time points.

RESULTS

MMP-9 and MMP-10 were greater in FR than basal ocular surface tears. After 8h of SL wear, the median concentration of MMP-9 in the FR and basal tears were 62.7 and 15.2 ng/mL, respectively (p = 0.047). Likewise, MMP-10 was significantly greater in FR compared to basal tears, after 8h (25.8 ng/mL vs 2.8 ng/mL, p < 0.001) and 4d (2.1 ng/mL vs17.2 ng/mL, p = 0.047). IL-4 and IL-8 levels were greater in FR but not significantly at 8h (2.2 vs 3.1 ng/mL; and 0.1 vs 0.4 ng/mL, respectively) or 4d (0.9 vs 3.5 ng/mL; 0.0 vs 0.2 ng/mL). MMP-7 was not affected by SL wear after 8h (46.0 basal vs 54.4 ng/mL FR) or 4d (34.2 vs 87.5 ng/mL). Visual acuity, corneal and conjunctival staining did not change; comfort was reduced in SL compared to soft contact lens wear.

CONCLUSIONS

This is the first study to compare the FR with the basal ocular surface tears. MMP-9 and MMP-10 were elevated in the FR after several hours of SL wear, suggesting potential clinical implications of SL wear and deserves further investigation.

Inhibitory effect of chitooligosaccharides on retinol metabolism and bioavailability in mice

This study investigated the intervention effects of chitooligosaccharides (COS) on retinol metabolism and included comparisons of the retinol level, retinol binding protein 4 (RBP4) content, key genes, and protein expression between mice on a COS-enriched diet and a normal diet. The results showed that COS markedly decreased the retinol and RBP4 concentrations in the serum and liver. Furthermore, COS suppressed the mRNA and protein expression of RBP4, cellular retinol binding protein 1 (CRBP1), lecithin: retinol acyltransferase (LRAT) and cytochrome P45026A1 (CYP26A1). In addition, COS inhibited the mRNA expression of stimulated by retinoic acid 6 (STRA6). However, the protein expression of STRA6 was not significantly decreased. Thus, COS reduced the retinol concentration in the serum and disrupted the metabolism of retinol. The intervention mechanism of COS on retinol metabolism may be attributed to the modulation of RBP4, CRBP1, LRAT, STRA6, and CYP26A1 expression at the mRNA and protein levels. PRACTICAL APPLICATIONS: Chitooligosaccharides (COS), known to be the degradation products of chitosan, have been found to induce pinkeye in industrial workers who participate in the manufacturing of COS. Meanwhile, 5% population with COS dietary supplement also have similar phenomenon. The aim of this study is to explore the possible mechanism underlay of this potential risk. The results of this study showed that high exposure to COS during manufacture influences retinol metabolism and leads to a decrease in retinol content, ultimately causing pinkeye. These findings provide new evidence for understanding COS-induced retinol metabolism alteration and drawing attention toward the prevention of potential risk in high-exposure populations.

Contact Lenses for Keratoconus- Current Practice

Background:

Keratoconus is a chronic, bilateral, usuallly asymmetrical, non-inflammatory, ectatic disorder, being characterized by progressive steepening, thinning and apical scarring of the cornea. Initially, the patient is asymptomatic, but the visual acuity gradually decreases, resulting in significant vision loss due to the development of irregular astigmatism, myopia, corneal thinning and scarring. The classic treatment of visual rehabilitation in keratoconus is based on spectacles and contact lenses (CLs).

Objective:

To summarize the types of CLs used in the treatment of keratoconus. This is literature review of several important published articles focusing on the visual rehabilitation in keratoconus with CLs.

Method:

Gas permeable (GP) CLs have been found to achieve better best corrected visual acuity than spectacles, eliminating 3rd-order coma root-mean-square (RMS) error, 3rd-order RMS, and higher-order RMS. However, they have implicated in reduction of corneal basal epithelial cell and anterior stromal keratocyte densities. Soft CLs seem to provide greater comfort and lower cost, but the low oxygen permeability (if the lens is not a silicone hydrogel), and the inability to mask moderate to severe irregular astigmatism are the main disadvantages of them. On the other hand, scleral CLs ensure stable platforms, which eliminate high-order aberrations and provide good centration and visual acuity. Their main disadvantages include the difficulties in application and removal of these lenses along with corneal flattening and swelling.

Result:

The modern hybrid CLs are indicated in cases of poor centration, poor stability or intolerance with GP lenses. Finally, piggyback CL systems effectively ameliorate visual acuity, but they have been related to corneal neovascularization and giant papillary conjunctivitis.

Conclusion:

CLs seem to rehabilitate visual performance, diminishing the power of the cylinder and the high-order aberrations. The final choice of CLs is based on their special features, the subsequent corneal changes and the patient’s needs.

Nonsurgical Procedures for Keratoconus Management

Objectives

To describe the past 20 years' correction modalities for keratoconus and their visual outcomes and possible complications.

Methods

A review of the published literature related to the visual outcomes and possible complications in the context of keratoconus management using nonsurgical procedures for the last 20 years (glasses and contact lenses) was performed. Original articles that reported the outcome of any correction modalities of keratoconus management were reviewed.

Results

The most nonsurgical procedure used on keratoconus management is the contact lens fitting. Soft contact lenses and soft toric contact lenses, rigid gas-permeable contact lenses, piggyback contact lens system, hybrid contact lenses, and scleral and corneoscleral contact lenses form the contemporary range of available lens types for keratoconus management with contact lenses. All of them try to restore the vision, improve the quality of life, and delay surgical procedures in patients with this disease. Complications are derived from the intolerance of using contact lens, and the use of each depends on keratoconus severity.

Conclusions

In the context of nonsurgical procedures, the use of contact lenses for the management of keratoconic patients represents a good alternative to restore vision and improve the quality of live in this population.

Scleral lens for keratoconus: technology update

Scleral lenses are large diameter lenses which rest over the sclera, unlike the conventional contact lenses which rest on the cornea. These lenses are fitted to not touch the cornea and there is a space created between the cornea and the lens. These lenses are inserted in the eyes after filling with sterile isotonic fluid. Generally, scleral contact lenses are used for high irregular astigmatism as seen in various corneal ectatic diseases such as keratoconus, pellucid marginal degeneration, or/and as liquid bandage in ocular surface disorders. In this article, we review the new developments, that have taken place over the years, in the field of scleral contact lenses as regard to new designs, materials, manufacturing technologies, and fitting strategies particularly for keratoconus.

Scleral Lenses

OBJECTIVE

To present a comprehensive review of current and historical literature on scleral lenses.

METHODS

A comprehensive search of several databases from each database's earliest inception to May 23, 2014 was conducted by an experienced librarian with input from the author to locate articles related to scleral lens design, fabrication, prescription, and management.

RESULTS

A total of 899 references were identified, 184 of which were directly related to scleral lenses. References of interest were organized by date, topic, and study design. Most of articles published before 1983 presented lens design and fabrication techniques or indications for scleral lens therapy. Case reviews published after 1983 identified major indications for scleral lenses (corneal ectasia, ocular surface disease, and refractive error) and visual and functional outcomes of scleral lens wear. Statistically significant improvements in visual acuity, vision-related quality of life, and ocular surface integrity were reported. Reviews of ocular and systemic conditions suggested that comprehensive management strategies for these conditions could include scleral lenses. Early work investigating scleral lens fitting characteristics, optical qualities, and potential physiological impact on anterior ocular structures have been published in the past 5 years.

CONCLUSIONS

Indications for scleral lens wear are well-established. Developing areas of research on the physiologic impact of scleral lens wear on the ocular surface, the use of technology to improve scleral lens vision and fit, and the impact of these devices on the quality of life should further enhance our understanding of scleral lenses in the future.