Evaluation of a Toric Implantable Collamer Lens After Corneal Collagen Crosslinking in Treatment of Early-Stage Keratoconus: 3-Year Follow-up

Refractive surgical approaches to keratoconus: A systematic review and network meta-analysis

Advancements in diagnostic methods and surgical techniques for keratoconus (KC) have increased non-invasive treatment options. Successful surgical planning for KC involves a combination of clinical science, empirical evidence, and surgical expertise. Assessment of disease progression is crucial, and halting the progression should be the focus if it is progressive. While surgeons used to rely on experience alone to decide the surgical method, comparing the network of primary factors, such as visual acuity, across studies can help them choose the most appropriate treatments for each patient and achieve optimal outcomes. Meticulous tabulation methods facilitate interpretation, highlighting the importance of selecting the correct surgical and rehabilitation approach based on each patient's condition and stage of the disease. We detail the outcomes of a comprehensive network meta-analysis comparing the effectiveness of various combined therapeutic refractive treatments for KC at identical stages of the disease, spanning 4 distinct follow-up intervals. Additionally, the comprehensive analysis suggests that for corneas with optimal best corrected visual acuity (BCVA) preoperatively (classified as regular), combining phakic intraocular lenses with intracorneal ring segments (ICRS) and corneal cross-linking (CXL) could offer the best therapeutic approach provided the disease stage does not exceed stage 3. For irregular corneas, although initial follow-ups show a significant difference in BCVA with surface ablation, longer-term follow-ups recommend combining surface ablation with ICRS and CXL, especially at higher stages.

Refractive surgical correction and treatment of keratoconus

Keratoconus is an ectatic corneal disorder that causes severe vision loss. Surgical options allow us to correct, partially or totally, the induced refractive error. Intracorneal ring segments (ICRS) implantation represents a minimally invasive surgical option that improves visual acuity, with a high success rate and a low overall complication rate. Corneal allogenic ICRS consists of ring segments derived from allogenic eye bank-processed donor corneas. Selective topography-guided transepithelial photorefractive or phototherapeutic keratectomy combined with CXL is another way in selected cases to improve spectacles corrected distance visual acuity. The microphotoablative remodeling of the central corneal profile is generally planned by optimizing the optical zones and minimizing tissue consumption. Phakic intraocular lens (PIOL) implant is considered in patients with stable disease and acceptable anatomical requirements. The two types of pIOLs, depending on their implantation inside the eye, are anterior chamber-pIOLs, which fixate to the anterior surface of the iris by using a polymethomethacrolate claw at the two haptics, and posterior chamber-pIOLs. In patients with both cataracts and keratoconus, the correct IOL power is difficult to obtain due to the irregular corneal shape and K values. Toric IOL is recommended, but carefully judging the topography and the possible need of subsequent keratoplasties.

The efficacy of 2 different phakic intraocular lens implant in keratoconus as an isolated procedure or combined with collagen crosslinking and intra-stromal corneal ring segments: a systematic review and meta-analysis

PURPOSE

To compare the efficacy of phakic intra-ocular lenses in isolation or in combination with corneal crosslinking (CXL) and/or intra-stromal corneal ring segments (ICRS) in keratoconus.

METHODS

Data extracted from the publications meeting the selection. The outcome parameters included mean pre- and post-operative uncorrected distance visual acuity, corrected distance visual acuity (CDVA), sphere and cylinder of refraction and complications. Available data analyzed with Cochrane Review Manager.

RESULTS

A total of 23 studies including 464 eyes were included. All the parameters showed significant improvement in all subgroups other than CDVA in ACPIOL + CXL subgroup and cylinder in PIOL + CXL subgroups. There was not a significant difference between PCPIOL and ACPIOL in the outcomes, exception was more improvement of CDVA in "ACPIOL only" than" PCPIOL only" subgroup.

CONCLUSION

Both PCPIOLs and ACPIOLs are comparably safe and efficient options in management of KCN and their efficacy significantly improves when combined with CXL/ICRS.

Toric Implantable Phakic Contact Lens in the Correction of Stable Keratoconus after Corneal Collagen Crosslinking

Background:

The study aims to evaluate the safety profile and efficacy of toric Implantable Phakic Contact Lens (IPCL) in patients with stable keratoconus after corneal collagen crosslinking (CXL).

Methods:

A prospective interventional case series study involving 30 keratoconic eyes between 22 to 39 years of age implanted with toric IPCL 6 months after CXL. The refractive error, visual acuity, corneal endothelium, intraocular pressure (IOP), and adverse effects were observed for 12 months following the implantation.

Results:

The preoperative mean for the sphere was approximately -8.3±3.6, which improved postoperatively by -0.58±0.23 after 1 month, -0.48±0.19 after 3 months, -0.36±0.18 after 6 months, and -0.35±0.2 after 12 months respectively. About the cylinder, the preoperative mean for the cylinder was approximately -3.4±1.6, which improved postoperatively by -1.06±0.3 after 1 month, -0.76±0.19 after 3 months, -0.48±0.28 after 6 months and -0.53±0.12 after 12 months, respectively. The preoperative BCDVA was 0.34±0.13, which increased postoperatively to 0.18±0.11 after 12 months. The mean values for IOP were 14.5±1.5 mm Hg, 15.1±2.09 mm Hg, 13.8±2.2 mmHg, 13.3±1.7 mm Hg, 13.1±1.6 mm Hg at preoperative period, 1 month, 3 months, 6 months and 12 months postoperatively. The mean preoperative endothelial count was 2912.9±111.1 per square millimeter, 2854.7±113.2 cells per square millimeter after 6 months, and 2829.0±112.2 cells per square millimeter after 12 months.

Conclusions:

Toric IPCL is a safe approach for treating residual refractive errors, particularly astigmatism, after 6 months of CXL in patients with stable KCS.

Clinical Outcomes of Toric Implantable Collamer Lens (T-ICL) and Toric Implantable Phakic Contact Lens (IPCL) for High Myopia with Astigmatism: A Comparative Study

Background:

Our study aimed to compare the clinical, visual outcomes, and efficacy of toric Implantable Collamer Lens (T-ICL) and toric implantable phakic contact lens (IPCL) in patients with high myopia and astigmatism over a follow-up period of 6 months.

Methods:

A prospective interventional randomized comparative study included 60 myopic eyes divided into 2 groups, group A including 30 eyes that were implanted with T-ICL, and group B, including 30 eyes that were implanted with toric IPCL. The refractive results, visual acuity, central corneal endothelial cell count, and intraocular pressure (IOP) were evaluated at baseline and at 1 and 6 months post-surgery. Any complications either during or after surgery were assessed.

Results:

In both study groups, the mean central corneal endothelial cell count was significantly decreased after 1 month and improved to reach near pre-operative values after 6 months postoperatively, indicating good lens biocompatibility. A statistically significant increase in IOP was found in both groups during the early follow-up, and a significant decrease after 6 months postoperatively (p=0.036) was reported in group A. A significant reduction in both spherical and cylindrical refractive errors with good predictability was reported in both groups compared with pre-operative values. Regarding the predictability, In T-ICL group (A), the median spherical and cylindrical errors were significantly improved from (-10 D & -4.5 D) pre-operatively to (-0.3 D & - 0.3 D) at the end of 6 months follow up period. Similarly, in the toric IPCL group (B), the median spherical and cylindrical errors were significantly improved from (-11 D & -4.5 D) pre-operatively to (-0.3 D & - 0.3 D) by the end of follow up period. A statistically significant improvement of UCDVA at 6 months postoperatively was found in both groups, as median preoperative LogMAR UCDVA was 1.1 and 1.3 in groups A and B respectively, which was improved to 0.3 in both groups at the end of follow-up period. There were no reported intra- or postoperative complications such as cataract, keratitis, or lens decentration.

Conclusion:

Toric IPCL is a suitable alternative to T-ICL for the management of high myopia with astigmatism, especially in developing countries, as it is cheaper and easier to implant than T-ICL. However, data over longer follow-up periods are needed to confirm its safety and stability.

Visual and Refractive Outcomes of Toric Implantable Collamer Lens Implantation in Stable Keratoconus After Combined Topography-Guided PRK and CXL

PURPOSE

To evaluate the safety and efficacy of toric implantable Collamer lens (ICL) (STAAR Surgical) implanted at least 6 months after combined topography-guided photorefractive keratotomy (TG-PRK) and corneal cross-linking (CXL) in keratoconus.

METHODS

This retrospective study included 46 eyes with keratoconus of 31 patients who underwent toric ICL implantation after previous TG-PRK+CXL. Patients were examined for uncorrected (UDVA) and corrected (CDVA) distance visual acuity, flat and steep keratometry, and manifest refraction spherical equivalent preoperatively and 12 months postoperatively.

RESULTS

At 12 months postoperatively, there was a statistically significant improvement in visual and refractive outcomes (all P < .001). Mean UDVA improved to 0.17 ± 0.14 logMAR (vs 1.00 ± 0.38 logMAR preoperatively) and mean manifest refraction spherical equivalent improved to -0.32 ± 1.42 diopters (D) (vs -7.35 ± 5.20 D preoperatively). At 12 months, 63% of eyes achieved UDVA of 20/32 or better and 60.9% of eyes were within ±0.50 D of manifest refraction spherical equivalent. Mean refractive astigmatism improved from -2.90 ± 2.21 D preoperatively to -1.47 ± 1.46 D at postoperative 12 months (P < .001), with 30.4% and 45.7% of eyes having a postoperative astigmatic error within ±0.50 and ±1.00 D, respectively. No complications were observed.

CONCLUSIONS

Toric ICL implantation was found to be safe and effective for the correction of myopia and myopic astigmatism in patients with stable keratoconus who had undergone TG-PRK+CXL, as revealed by the statistically significant improvement in visual and refractive outcomes at 12 months after toric ICL implantation. [J Refract Surg. 2021;37(12):824-829.].

Simplifying and understanding various topographic indices for keratoconus using Scheimpflug based topographers

Keratoconus (KC) is a progressive ectatic corneal disorder. There are multiple topographic devices and their varied indices used for diagnosis, detecting progression, and deciding management. It is important to understand the repeatablility, intra- test variabililty, and comparability amongst various topographic devices. The Scheimpflug camera-based devices, such as the Pentacam (Oculus, Wetzlar, Germany), Galilei (Ziemer, Biel, Switzerland), and Sirius (Costruzione Strumenti Oftalmici, Florence, Italy) are known to assist in the detection of early keratoconus and subclinical keratoconus. This article reviews the various Scheimpflug camera-based devices in depth, addressing their different indices, diagnostic accuracy, repeatability, and agreement and identifying the strongest parameter of each device. It will guide the practicing clinician by giving practical tips for decision making in the diagnosis and management of keratoconus.

Posterior Chamber Phakic Intraocular Lens Implantation for Refractive Correction in Corneal Ectatic Disorders: A Review

PURPOSE

To summarize the indications and outcomes of posterior chamber phakic intraocular lens (PIOL) implantation in corneal ectasias including keratoconus, pellucid marginal degeneration (PMD), post-refractive surgery, and post-keratoplasty ectasias.

METHODS

A review of the literature was conducted using the relevant keywords from various databases up to August 15, 2020. All pertinent studies were reviewed, and the relevant articles were studied in detail for efficacy, stability, predictability, and safety outcomes. In addition, visual quality, corneal biomechanical outcomes, complications, the role of posterior chamber PIOL in combination treatment, and comparison of posterior chamber PIOL with other PIOLs for ectasias were also evaluated.

RESULTS

A total of 30 relevant studies (13 prospective, 13 retrospective, 4 case reports) on the subject were studied and summarized. All studies showed a favorable refractive outcome. Quality of vision remained unaffected and no significant complications were reported in any of the studies.

CONCLUSIONS

Posterior chamber PIOLs represent a viable option in the treatment of mild to moderate and stable corneal ectasia in patients with contact lens intolerance who have low irregular astigmatism, a clear central cornea, and good preoperative corrected distance visual acuity. [J Refract Surg. 2021;37(5):351-359.].

Outcomes and complications of implantable collamer lens for mild to advance keratoconus

PURPOSE

To evaluate the outcome and safety of implantable collamer lens (ICL; (Visian, STAAR Surgical, Monrovia, CA, USA) in mild to advance keratoconus patients with myopia and myopic astigmatism.

METHODS

This retrospective study evaluated all patients who underwent ICL implantation for the management of keratoconus at a tertiary care eye hospital from January 2012 to January 2018. The mean duration of follow-up was 15.3 months (range, 3.13 to 38.97 months). Data were collected on preoperative and postoperative uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA), refraction was compared, and adverse effects were evaluated.

RESULTS

Thirty-two eyes (32 patients) were evaluated. The median CDVA was 20/30 preoperatively and 20/20 at last follow-up. The median UDVA was 20/25 at last follow-up. Thirteen patients (40.6%) had 20/20 UDVA in comparison to none at baseline. The median spherical equivalent in diopters (D) was -7.875 D (-4.125 to -10.0 D) preoperatively and decreased to -0.3125 D at last follow-up. The median manifest refractive cylinder was 3.00 D (2.25 to 5.25 D) preoperatively and decreased to 1.125 D postoperatively. Cylinder axis rotation of 10° or greater occurred in 3 eyes (9.375%) and required repositioning of the ICL. One patient (3%) developed nonvisually significant anterior subcapsular cataract. One ICL (3.125%) had to be explanted due to residual refractive error and unsatisfactory vision.

CONCLUSION

ICLs are a suitable refractive option for the correction of refractive error associated with stable, nonprogressive keratoconus even in advance cases. However, the risk of ICL rotation and subsequent repositioning remain. Careful patient selection is necessary for achieving good outcomes and mitigating intraoperative and postoperative complications.

Toric intraocular lens power calculation in cataract patients with keratoconus

Purpose

Intra-ocular lens (IOL) power calculation in eyes with keratoconus typically results in hyperopic postoperative refractive error. We investigated the visual and refractive outcomes in keratoconus patients having cataract surgery with a toric IOL and compared IOL power calculation accuracy of conventional formulae and keratoconus specific formulae.

Setting

Ein-Tal Eye Center, Tel-Aviv, Israel.

Design

Retrospective case-series study.

Methods

Post-operative visual acuity and manifest refraction were examined. The error in predicted refraction and IOL power calculation accuracy within a range of 0.5 to 2.0 diopters were compared between different IOL calculating formulae.

Results

Thirty-two eyes with keratoconus were included. Visual acuity improved in all cases and subjective astigmatism decreased from -2.95+/-2.10 D to -0.95+/-0.80 D (p<0.001). Mean absolute errors were: Barrett True-K for keratoconus with measured or predicted posterior corneal power, 0.34 D; Barrett Universal II, 0.64 D; Kane Formula, 0.69 D; Kane Formula for keratoconus, 0.49 D; SRK/T, 0.56 D; Haigis, 0.72 D; Holladay 1, 0.71 D and Hoffer Q, 0.87 D. Barrett True-K formula with measured posterior corneal power, SRK/T and Kane Formula for keratoconus resulted in a prediction error within 0.5 D of 87.5%, 59.4% and 53.1%, respectively.

Conclusions

Cataract removal with a toric IOL significantly improves visual acuity and decreases astigmatism in keratoconic eyes with a topographic central relatively regular astigmatic component. Keratoconus specific formulae resulted in lower mean error in predicted refraction compared with conventional calculating formulae. Utilizing the posterior corneal power within the Barrett True K formula for keratoconus improved IOL power prediction accuracy.

Corneal cross-linking (CXL) combined with refractive surgery for the comprehensive management of keratoconus: CXL plus

The past two decades have witnessed an unprecedented evolution in the management of keratoconus that demands a holistic approach comprising of inhibiting the ectatic progression as well as visual rehabilitation. The advent of corneal cross-linking (CXL) in the late 1990s resulted in long-term stabilization of the ectatic cornea along with limited reduction in corneal steepening and regularization of corneal curvature. However, CXL as a standalone procedure does not suffice in rehabilitating the functional vision especially in patients who are unwilling or intolerant towards contact lenses. The concept of “CXL plus” was proposed which incorporates adjunctive use of refractive procedures with CXL in order to overcome the optical inefficiency due to corneal irregularity, decrease the irregular astigmatism, correct the residual refractive error and improve functional visual outcome in keratoconus. Several refractive procedures such as conductive keratoplasty (CK), photorefractive keratectomy (PRK), transepithelial phototherapeutic keratectomy (t-PTK), intrastromal corneal ring segments (ICRS) implantation, phakic intraocular lens (PIOL) implantation and multiple other techniques have been combined with CXL to optimize and enhance the CXL outcome. This review aimed to summarize the different protocols of CXL plus, provide guidelines for selection of the optimum CXL plus technique and aid in decision-making for the comprehensive management of cases with primary keratoconus in addition to discussing the future and scope for innovations in the existing treatment protocols.

Phakic intraocular lenses: Recent advances and innovations

Phakic intraocular lenses (pIOL) are recommended when counselling refractive surgery candidates presenting with high ametropia or ocular surface and/or corneal conditions that contraindicate corneal refractive surgery. This review aims to present the state-of-the-art regarding pIOL models currently available in Europe, addressing their newer indications and recent design innovations. These include, in the case of posterior chamber pIOLs, the addition of a central hole to improve aqueous humour circulation, the availability of larger optical zones, and multifocal optics for the compensation of presbyopia. The review also highlights their good safety and efficacy results, as well as the role of patient education to ensure adequate outcomes in the medium-long term. The indications of pIOLs in special situations, as well as bi-lensectomy, a procedure that most pIOL patients may eventually require as they age and develop cataracts, are also addressed.

Visual and refractive outcomes of posterior chamber phakic IOL in stable keratoconus

We evaluated the visual and refractive outcomes after phakic visian toric implantable collamer lens (ICL) insertion in stable keratoconus (KC). This retrospective study investigated toric ICL implantation in 14 eyes of 8 patients with stable KC. After 6mo, the mean uncorrected distance visual acuity improved significantly from 0.77 to 0.15 logMAR. The mean best corrected distance visual acuity (BCDVA) improved from 0.18±0.1 to 0.15±0.1 logMAR. Fifty percent of eyes maintained their preoperative BCDVA; 42.8% gained one line. There was no statistical difference in high order or coma aberration. The mean refractive manifest spherical equivalent (MSE), mean refractive manifest spherical error, mean manifest astigmatism decreased significantly postoperatively. At 6mo postoperatively, our achieved mean spherical equivalent was approximately 74%. No intraoperative or postoperative complications occurred. Toric ICL implantation was effective, predictable and safe to correct refractive error and improve visual acuity in patients with stable KC.

Intrasubject Repeatability and Interdevice Agreement of Anterior Chamber Depth Measurements by Orbscan and Pentacam in Different Grades of Keratoconus

OBJECTIVES

To evaluate the repeatability of anterior chamber depth (ACD) measurements by Orbscan and Pentacam imaging devices in different grades of keratoconus.

METHODS

One examiner performed 3 consecutive ACD measurements with both devices on 74 eyes of 42 keratoconus patient. Repeatability was assessed using intrasession test-retest variability. Within-subject SD was determined for repeatability, and the coefficient of variation was calculated for each measurement. The intraclass correlation coefficient (ICC) was also determined to assess the variance of repeated data.

RESULTS

Overall, the three ACD measurements were not significantly different either with Pentacam or Orbscan. The ICC index values were greater than 90% with both devices, and it significantly reduced at higher grades of keratoconus with Pentacam. Interdevice differences were statistically significant. The interdevice agreement with ACD measurements was 0.981, and the agreement was lower at higher grades of keratoconus. The 95% limits of agreement between the 2 devices for ACD was from -0.19 to 0.04.

CONCLUSIONS

Our results indicate acceptable repeatability for ACD measurements with both Orbscan and Pentacam in keratoconus patients. The progression of keratoconus has no significant effect on repeatability results of these devices. The good agreement between them allows their interchangeable use.

Surgical Options for the Refractive Correction of Keratoconus: Myth or Reality

Keratoconus provides a decrease of quality of life to the patients who suffer from it. The treatment used as well as the method to correct the refractive error of these patients may influence on the impact of the disease on their quality of life. The purpose of this review is to describe the evidence about the conservative surgical treatment for keratoconus aiming to therapeutic and refractive effect. The visual rehabilitation for keratoconic corneas requires addressing three concerns: halting the ectatic process, improving corneal shape, and minimizing the residual refractive error. Cross-linking can halt the disease progression, intrastromal corneal ring segments can improve the corneal shape and hence the visual quality and reduce the refractive error, PRK can correct mild-moderate refractive error, and intraocular lenses can correct from low to high refractive error associated with keratoconus. Any of these surgical options can be performed alone or combined with the other techniques depending on what the case requires. Although it could be considered that the surgical option for the refracto-therapeutic treatment of the keratoconus is a reality, controlled, randomized studies with larger cohorts and longer follow-up periods are needed to determine which refractive procedure and/or sequence are most suitable for each case.

Comparative analysis of the visual performance after implantation of the toric implantable collamer lens in stable keratoconus: a 4-year follow-up after sequential procedure (CXL+TICL implantation)

Aims

To report on 4-year postoperative visual performance with the toric implantable collamer lens (TICL) for stable keratoconus after sequential procedure (corneal collagen crosslinking plus TICL implantation).

Methods

Forty eyes of 24 patients with stable keratoconus with myopia between 0.00 and −18.00 dioptres (D) and astigmatism between 1.25 and 8.00 D were evaluated in this prospective interventional study (https://clinicaltrials.gov/ct2/show/NCT02833649). We evaluated refraction, visual outcomes, astigmatic changes analysed by Alpins vector, contrast sensitivity, aberrometry, modulation transfer functions (MTFs), defocus curve, and operative and postoperative complications.

Results

At 4-year follow-up, 45% had 20/20 vision or better and 100% had 20/40 or better uncorrected visual acuity (UCVA). Vector analysis of refractive astigmatism shows that the surgically induced astigmatism (SIA) (3.20±1.46 D) was not significantly different from the target induced astigmatism (TIA) (3.14±1.42 D) (p=0.620). At 4 years postoperatively, none of the eyes showed a decrease in UCVA, in contrast to 24 eyes in which UCVA was increased by ≥1 lines, with contrast sensitivity and improvement in total aberrations and MTF value at 5 per degree (*p=0.004) after TICL implantation. The cumulative 4-year corneal endothelial cell loss was ≤5%. No patients reported dissatisfaction. At the end of follow-up, the vault was 658±54.33m (range, 500–711) and the intraocular pressure was 11.7±2.08 mm Hg. Occurrences of glare and night-driving troubles diminished after TICL surgery.

Conclusion

The results from this standardised clinical investigation support TICL implantation from clinical and optical viewpoints in patients with stable keratoconus.

Trial registration number

NCT02833649, Pre-results

Keratoconus Treatment Algorithm

Keratoconus management has significantly changed over the last two decades. The advent of new interventions such as cornea cross-linking, intrastromal corneal ring segments, and combined treatments provide corneal clinicians a variety of treatment options for the visual rehabilitation of keratoconus patients. This review summarizes current evidence for these treatments and highlights their place in keratoconus management while new promising emerging therapies are being investigated.

Safety and Visual Outcome of Visian Toric ICL Implantation after Corneal Collagen Cross-Linking in Keratoconus: Up to 2 Years of Follow-Up

Purpose. To evaluate the long-term safety and clinical outcome of phakic Visian toric implantable collamer lens (ICL) insertion after corneal collagen cross-linking (CXL) in progressive keratoconus. Methods. This was a retrospective study of 30 eyes (19 patients), with progressive keratoconus, who underwent sequential CXL followed by Visian toric ICL implantation after 6 months. Results. At baseline, 6 eyes had stage I, 14 eyes stage II, and 10 eyes stage III keratoconus graded by Amsler-Krumeich classification. At 6 months after CXL, only K (steep) and K (max) decreased significantly from baseline, with no change in visual acuity or refraction. Flattening in keratometric readings was stable thereafter. There was significant improvement in mean uncorrected distance visual acuity (1.57 ± 0.56 to 0.17 ± 0.06 logMAR, P < 0.001) and mean corrected distance visual acuity (0.17 ± 0.08 to 0.11 ± 0.05 logMAR, P < 0.001) at 12 months after ICL implantation that was maintained at the 2-year follow-up. Mean cylinder power and mean spherical equivalent (SE) also decreased significantly after ICL implantation. A small hyperopic shift in SE (+0.25 D) was observed at 2 years that did not alter visual outcomes. Conclusions. Visian toric ICL implantation following CXL is an effective option for improving visual acuity in patients with keratoconus up to 2 years.

Implantable collamer lens in a case of corneal scar with anisometropic amblyopia in an adult: an expanded indication

A 35-year-old man, a unilateral high myope with corneal scarring, presented for evaluation. He had a stromal scar that started temporally, traversed along the pupillary zone partially and extended across the horizontal diameter of the cornea. The Descemet's membrane appeared intact even though the scar was extending into deep stroma towards the nasal end, as seen in the optical coherence tomography image. The patient had an uncorrected distance visual acuity (UDVA) of 4/60 OD, which improved with a refraction of -9.0 DS/-1.50 DC at 15 to 6/18p and 6/6p OS. He underwent an uneventful toric implantable collamer lens (ICL) implantation of -15.0 D/-2.0 D at 102 after preoperative yttrium-aluminium-garnet (YAG) laser iridotomy in the right eye. The postoperative UDVA and corrected distance visual acuity for the right eye were 6/12 and 6/9p (with a refraction of +0.50 D/-0.50 D at 85), respectively. The corneal scar and topography were stable. This case reports an expanded indication for toric ICL in cases with corneal scar/opacity but good spectacle corrected visual acuity.

Current review and a simplified "five-point management algorithm" for keratoconus

Keratoconus is a slowly progressive, noninflammatory ectatic corneal disease characterized by changes in corneal collagen structure and organization. Though the etiology remains unknown, novel techniques are continuously emerging for the diagnosis and management of the disease. Demographical parameters are known to affect the rate of progression of the disease. Common methods of vision correction for keratoconus range from spectacles and rigid gas-permeable contact lenses to other specialized lenses such as piggyback, Rose-K or Boston scleral lenses. Corneal collagen cross-linking is effective in stabilizing the progression of the disease. Intra-corneal ring segments can improve vision by flattening the cornea in patients with mild to moderate keratoconus. Topography-guided custom ablation treatment betters the quality of vision by correcting the refractive error and improving the contact lens fit. In advanced keratoconus with corneal scarring, lamellar or full thickness penetrating keratoplasty will be the treatment of choice. With such a wide spectrum of alternatives available, it is necessary to choose the best possible treatment option for each patient. Based on a brief review of the literature and our own studies we have designed a five-point management algorithm for the treatment of keratoconus.

Evaluation of the toric implantable collamer lens for simultaneous treatment of myopia and astigmatism

Myopic astigmatism is a prevalent condition that can be treated with spectacles, contact lenses, or laser refractive surgery. However, these treatment options have functional limitations at higher levels of refractive error. The toric implantable collamer lens is designed to treat a broad range of refractive error, generally up to -18 diopters with +1 to +6 diopters of astigmatism. Approval for a more limited treatment range of up to 15 diopters of myopia with +1 to +4 diopters of astigmatism is being sought in the US, where this device has not yet received marketing approval. Surgical correction of high-myopic astigmatism can be life-altering and allow people to participate in activities that were not previously feasible because of visual limitations. The toric implantable collamer lens is implanted behind the iris and in front of the natural crystalline lens. With earlier lens designs, it was necessary to create an iridectomy or iridotomy to prevent pupillary block. The newest toric implantable collamer lens model has a small central hole that is not visually noticeable. This eliminates the need to create a hole in the iris, thereby enhancing the safety of the procedure.