Intraocular lens power calculation after excimer laser corneal refractive surgery: A retrospective study to compare the predictability and the efficacy of commonly used and modified formulas.

PURPOSE: Our article aims to assess the accuracy of modified and commonly used formulas of intraocular lens (IOL) power calculation after excimer laser corneal refractive surgery. METHODS: This is a retrospective study, with data retrieved for 50 eyes of 32 patients who underwent uncomplicated cataract surgery after excimer laser corneal refractive surgery. The expected spherical equivalent was calculated using the American Society of Cataract and Refractive Surgeons (ASCRS) IOL power calculator for Shammas and Barrett True-K, using three-fourth generation formulas (Haigis-L, Barrett True-K no history, and Holladay 2), and using three-third generation formulas (SRKT, Holladay 1, and Hoffer Q) with single k, as a reference, and adjusting these formulas by calculating the keratometry readings by two methods (Jarade's index and formula). The mean refractive error and mean absolute refractive error (MARE) were calculated at the 1 postoperative month. RESULTS: When all data was available (eight eyes), 13 formulas were compared. Holladay 1 as modified by Jarade's index and formula, and Hoffer Q as modified by Jarade's formula resulted in MARE <0.75D (P < 0.05). In the group of 25 eyes with only ablation available, the formulas with MARE <0.75D were Haigis L, Barrett TK (from ASCRS), Hoffer Q, and the three conventional formulas in Jarade's index (P < 0.001). In the group of 17 eyes with no available prerefractive data, only Haigis-L and Barret TK (no history) had a MARE <0.75 D. CONCLUSION: The use of Hoffer Q or Holladay 1, when prerefractive data are available, gives reliable results with Jarade's index.

Cataract in keratoconus: Six-month results and a comparison of standard intraocular lens power calculation formulas.

PURPOSE: To report the results of cataract surgeries in keratoconus patients at 1 and 6 months postoperatively, and to compare the standard intraocular lens (IOL) calculation formulas in this population. METHODS: This is a retrospective study, carried out in 44 eyes of 26 patients known to have keratoconus who underwent cataract surgery at Beirut Eye and ENT Specialist Hospital between 2010 and 2021. The patients were divided into groups based on Dr Jarade updated algorithm. Visual acuities before and after cataract surgery, at 1 and 6 months were recorded, as well as spherical equivalent. The difference between the expected spherical equivalent with each formula was subtracted from the actual resultant refraction, and its absolute value deduced. The means of the values were calculated and the 4 standard formulas (SRK/T, SRK/II, Holladay, and Hoffer Q) were compared. RESULTS: Six eyes had similar topographic and manifest axes (category 1) and underwent toric IOL implantation. Corrected distance visual acuity (CDVA) at 1 and 6 months was 0.2 and 0.1 logMAR, respectively. 26 eyes had mismatching axes and had monofocal IOL placement. CDVA at 1 and 6 months was 0.3. Six eyes required intrastromal corneal ring placement before operating (category 3). CDVA was 0.3 and 0.2 at 1 and 6 months, respectively. Regarding category 4, requiring keratoplasty and cataract extraction, CDVA was 0.4 at both follow-ups. No statistically significant difference was found between the different formulas. CONCLUSION: Categorization of keratoconus patients gave favorable results after cataract surgery. No superior IOL formula was found.

Corneal Cross-Linking for Keratoconus and Post-LASIK Ectasia and Failure Rate: A 3 Years Follow-Up Study.

Purpose To report the response of keratoconus (KC) and post-LASIK ectasia (referred to as "ectasia") to the corneal crosslinking (CXL) and to compare the rate of progression between KC and ectasia at three years. Methods A retrospective cohort study of patients undergoing CXL for either KC or ectasia. Fifty-four eyes (31 patients) with ectasia and 111 eyes (67 patients) with KC were included in the study. Corrected distance visual acuities (CDVA), refraction, keratometry (K), and pachymetry were followed up for three years. Simultaneous photorefractive keratectomy (PRK) and CXL were performed on 20 KC and 20 ectasia eyes. Intrastromal Corneal Ring Segments (ICRS) were performed on 51 KC and six ectasia eyes. Results In KC, CDVA, spherical equivalence, sphere, cylinder, and mean K improved at three years post-CXL (p-value<0.05), but these values improved without reaching a statistical significance in ectasia(p-values <0.05). 12 of 54 eyes with ectasia (22.2%) and 4 of 111 eyes (3.6%) with KC had progression post CXL(p-value:0.0001). Ectasia patients diagnosed with progression were older at presentation (36.1 years) than non-progressive ectasia patients (31 years) (p-value 0.02) and also older than KC patients. Sub-analysis excluding PRK and ICRS cases showed that there was an improvement in mean sphere (from -5.23±4.2D to-4.46±3.89D) (p-value 0.03) cylinder (from 2.54 ± 1.68D to 1.97 ± 1.51D) (p-value 0.03) mean keratometry (from 46.81 ± 3.78D to 46.01 ± 3.25D) (p-value 0.006) in KC patients 3 years post CXL (40 patients). Compared to baseline, all the mean refractive and topographic variables deteriorated at three years post CXL in ectasia (28 patients) (p-value>0.05). Also, 2 of 40 patients with KC (5%) vs. 7 of 28 patients with ectasia (25%) had progression three years post-CXL, and the difference between both groups remained statistically significant(p-value 0.027). Conclusion Eyes with post-LASIK ectasia seem to be less responsive to CXL than KC.

The use of soft contact lens for intraocular foreign body removal to avoid inadvertent cataract formation.

Ocular injuries carry a significant morbidity worldwide. Visual outcomes vary depending on the mechanism of injury, the damage on arrival and the surgical technique used. The presence of an intraocular foreign body further complicates matters, due to its constituents, the infectious potential, and/or damage to intraocular structures. Another described problem is the inadvertent cataract formation due to contact with the natural lens during removal of the foreign body. The purpose of this paper is to describe a case with a mechanical foreign body lodging in the posterior chamber without harming the lens. The surgical challenge was to remove it without causing cataractous changes. Therefore, a soft contact lens was used to form a protective layer between the foreign body and the natural lens of the eye allowing successful removal of the foreign body.

Incidence, Risk Factors and Treatment Outcomes of Intraocular Hypertension and/or Glaucoma Post-Penetrating Keratoplasty: A 5-Year Lebanese Retrospective Descriptive Study.

PURPOSE: Glaucoma is one of the most common complications post-penetrating keratoplasty (PK). In this study, we report the Incidence, risk factors and treatment outcomes of intraocular hypertension (IOH) or/and glaucoma post-penetrating keratoplasty (PKG). METHODS: A 5-year descriptive retrospective study, Lebanese patients who underwent PK at Beirut Eye & ENT Specialist Hospital, between 2012 and 2017, were included. Patients with history of glaucoma were excluded. IOH/PKG cases that necessitate treatment were identified and analyzed for the incidence, risk factors and treatment outcomes. RESULTS: A total of 189 eyes of 159 patients were included, with male/female ratio 1.6 and the mean age 47.2±21.3 years. Bullous keratopathy (BK) presented with a high mean age: 70.3 years while ectasia patients were the youngest: 36.5 years. 34.9% of eyes developed high IOP within a mean of 25 months of follow-up distributed between sub-groups of patient with corneal ectasia (22.5%), redo-PK (51.2%), bullous keratopathy (BK) (50%), keratitis (24.9%), and others (dystrophy, trauma …) (21.4%). High IOP developed in 67.4% of the diabetic patients. Visual acuity was less likely to improve in cases developing elevated IOP while postoperative complications were significantly high. In those refractory to medical treatment, trabeculectomy as a glaucoma surgery was effective in lowering the IOP. Combining procedures with PK was not a risk factor for glaucoma. Interrupted sutures and higher number of suturing were associated with increased IOP levels. CONCLUSION: IOH developed in one out of three patients who underwent penetrating keratoplasty. DM, bullous keratopathy, infectious keratitis and redo-PK were highly associated with PKG, whereas high IOP was less likely to develop in cases with keratoconus. Glaucoma is considered a poor prognostic factor in patients post-PK.

The Effect of Age on Corneal Topographic Indices, Keratometry and Visual Acuity After Combined Intrastromal Corneal Ring Segment (ICRS) Implantation and Corneal Crosslinking.

We aimed to assess age-related changes in corneal topographic indices, keratometry and visual acuity after sequential intracorneal ring segment implantation (ICRS) and crosslinking (CXL). This was a retrospective matched case-control series including 26 eyes of patients ≤18 years as cases and 26 eyes of adult patients as controls. All eyes received ICRS+CXL for progressive keratoconus. Eyes were matched regarding the keratoconus parameters and the treatment (type, number and thickness of ICRS). Data was analyzed for refractive and topographic values (uncorrected and corrected distance visual acuity (UDVA; CDVA) sphere; cylinder; spherical equivalent; maximum keratometry (Kmax); flat keratometry (Kflat); steep keratometry (Ksteep); all 7 pentacam topographic indices) preoperatively and one year postoperatively. Preoperatively, there was no significant difference for any refractive, clinical or topographic parameters between the groups except for index of vertical asymmetry. After one year, children had a significantly higher improvement in Ksteep (3.05D) than adults (2.10D; P=0.036) and a trend to significance for Kflat (2.7D compared to 1.78D, respectively; P=0.081). UDVA improved by 4.3 ETDRS lines in children compared to 3.3 ETDRS lines in adults and CDVA improved by 1.7 ETDRS lines in children compared to 1.2 ETDRS lines in adults, but with no statistical significance. The effects on keratometry indicated that corneal response after ICRS and CXL for keratoconus is more pronounced in young patients than adults. This assumption is also supported by functional improvement and by the fact that a few eyes (5) of some very young patients (<13years) showed highly remarkable improvements after surgery (higher than any adult eye).

A Modified Customized Rigid Gas Permeable Contact Lens to Improve Visualization During Phacoemulsification in Ectatic Corneas.

Advanced Keratoconus and ectatic corneal diseases may lead to corneal thinning and irregular astigmatism. The optical distortion caused by these pathologies may result in poor visibility for the surgeon during phacoemulsification. Thus, the risk of complication would be increased intraoperatively (capsular rupture, vitreous loss). The aim of this case series was to use a modified customized Rigid Gas Permeable (RGP) contact lens to improve visualization during all the stages of phacoemulsification in irregular corneas and to avoid open sky technique for cataract removal during penetrating keratoplasty (PK). A customized, 12 mm, RGP contact lens was designed and manufactured. Two peripheral notches were customized to fit the hand position of the surgeon (at 11 O'clock and 2 Clock in this case series) to allow clear corneal incisions. Six eyes of 6 patients were included (3 eyes with advanced keratoconus and a severely optically distorted, yet clear corneas, planned for PK on the same day; 2 eyes were status post-intracorneal ring segment implantation for stage 4 keratoconus and 1 eye had combined phacoemulsification with superficial keratectomy to remove paracentral corneal Salzmann's nodule). Lens opacities ranged from +2 to +4 nuclear sclerosis in all eyes. Good visualization of the anterior lens and capsule attained with the RGP contact lens fitting. Improved visualization was reported during all the steps (Capsulorhexis, Irrigation/Aspiration, Phaco. Intraocular lens implantation). The phacoemulsification was smooth and non-complicated in a total of 6 eyes of 6 patients. In these cases, without RGP fitting, the operation was not technically possible. The customized notches allowed any insertion of surgical instruments, and with the help of viscoelastic maintained a good stability of the contact lens during the operation. We concluded that customized method RGP contact lens, may help reducing complications during phacoemulsification in advanced corneal ectasia and perhaps in irregular corneas as well.

Unilateral Malignant Glaucoma Postbilateral Implantable Collamer Lens: Effect of Miotics.

An implantable collamer lens® (ICL) V4c model (STAAR Surgical, Monrovia, CA, USA) was placed in the eye of a 31-year-old male patient with high myopia followed by the development of malignant glaucoma. After failing medical treatment for 5 days, a noncomplicated pars plana vitrectomy and anterior hyaloidectomy succeeded in breaking the aqueous misdirection. Sixteen months later, intraoperative miotics were purposefully withheld from the ICL surgery in the fellow eye and malignant glaucoma did not develop. Even though the patient's visual acuity postoperatively was 20/20, OU, a single small atrophic iris patch in the affected eye resulted in slightly more halos and glare in mesopic conditions as compared to the fellow eye. Earlier surgical intervention may have prevented iris ischemia and iridocorneal touch with its subsequent iris atrophy and resulted in an even more favorable visual outcome. Withholding intraoperative miotics during ICL surgery appeared to be beneficial in this case.

Management of cataract in keratoconus: early visual outcomes of different treatment modalities.

A review of 31 eyes with keratoconus who developed cataract and underwent phacoemulsification. Visual acuities were measured 1mo postoperatively. Six eyes with a history of good corrected distance visual acuity (CDVA) and a similar refractive and topographic astigmatic axis were implanted with toric intraocular lenses (IOLs). The mean postoperative uncorrected distance visual acuity (UDVA) was 0.2 logMAR with a spherical equivalent (SE): 0.75D. Eleven eyes with a history of good CDVA and different refractive and topographic axis were implanted with monofocal IOL+/-Toric implantable collamer lenses to treat anisometropia and ametropia; mean UDVA was 0.25 logMAR with a mean SE: -0.51 D postoperatively. Six eyes with poor CDVA were first treated with intra-corneal ring segments, followed by phacoemulsification, the mean postoperative UDVA was 0.82 logMAR with an SE: 0.22 D. Eight eyes had advanced ectesia and received combined phacoemulsification and penetrating keratoplasty. Our approach is efficient in addressing ametropia after cataract surgery in keratoconic eyes.

Biologic stromal ring to manage stromal melting after intrastromal corneal ring segment implantation.

We report a new technique to replace a manufactured poly(methyl methacrylate) (PMMA) ring with a biologic stromal ring fashioned from human corneal donor tissue in eyes with stromal melting above the PMMA ring. The biologic stromal ring is prepared using manual or femtosecond laser trephination of a donor cornea to obtain a 360-degree ring that is denuded and adjusted to match the PMMA ring being replaced. The biologic ring is attached to the PMMA ring. The PMMA ring is pushed and retrieved from the other side, which installs the biologic ring in place. Six biologic stromal rings were implanted successfully in 5 eyes of 5 patients with previous stromal melting; no complications were reported up to 6 months postoperatively. The biologic stromal ring stopped and healed the melting, prevented further ring complications, and preserved the therapeutic refractive effect of the previously implanted PMMA ring.

Corrigendum to "Under-the-Flap Crosslinking and LASIK in Early Ectasia with Hyperopic Refractive Error".

[This corrects the article DOI: 10.1155/2018/4342984.].

Late-Onset Sterile Peripheral Ulcerative Keratitis Post-Corneal Collagen Crosslinking.

PURPOSE: To report the incidence, characteristics, clinical presentations, risk factors, and the available treatment modalities of sterile peripheral ulcerative keratitis (PUK) post-corneal collagen crosslinking (CXL). METHODS: This study is a retrospective study including 771 eyes of 474 patients operated for keratoconus or ectasia after LASIK between January 2010 and June 2017 at Beirut Eye & ENT Specialist hospital. The average follow-up period was 4.2 years with a minimum of 1 year post-CXL. RESULTS: Eleven eyes (1.4%) of 8 patients developed late-onset PUK with or without corneal haze and sterile infiltrates. The complications occurred between 3 months and 6 years postoperatively. Their mean age of 39.6 ± 7.1 years was higher than the age of the noncomplicated patients 21.9 ± 8.8 years (P = 0.0001). Four affected patients had inflammatory and autoimmune conditions. Sex, presence of intrastromal ring segments, mean keratometry, and the thinnest pachymetry were found to be insignificantly different between groups, and photorefractive keratectomy was performed more in patients with keratitis. Duration of ultraviolet light exposure was related to sterile ulcerative keratitis development. All patients responded to steroid treatment, and only one had a relapse which resolved with topical cyclosporine 1% drops. CONCLUSIONS: PUK is a rare but serious complication after CXL. Long-term follow-up is necessary to detect late-onset PUK. It is a treatable condition associated with older age and autoimmune conditions but has a good visual outcome.

Under-the-Flap Crosslinking and LASIK in Early Ectasia with Hyperopic Refractive Error.

PURPOSE: To present safety, efficacy, and early results of a new combinational treatment for early corneal ectasia with hyperopic refractive error aimed to reinstate emmetropia and stabilize cornea. METHOD: This is a retrospective case series. All surgeries were performed at the Beirut Eye Specialist Hospital, Lebanon. Surgical procedure consisted of (1) lifting flap (post-LASIK ectasia)/creation of corneal flap (keratoconus), (2) application of excimer laser ablation to correct refractive error, (3) loose repositioning of flap, (4) under-the-flap irrigation with riboflavin 0.1% dextran solution, and (5) application of UVA light. RESULTS: A total of 7 eyes (4 patients; mean age 24.25 years; all male) were included. 2 patients had early keratoconus, and 2 patients had early post-LASIK ectasia. Pretreatment vs. last postoperative follow-up visit (mean 11.25 months; range 6-15 months) UDVA (logMAR), spherical equivalent (SE) (D), astigmatism (D), and central pachymetry (µm) were 0.35 ± 0.18 vs. 0.05 ± 0.07, p=0.017; -0.81 ± 0.67 vs. -0.46 ± 0.57, p=0.078; 2.46 ± 0.53 vs. 0.68 ± 0.28, p=0.018; and 547 ± 58 vs. 536 ± 49, p=0.07, respectively. In all eyes, BCVA was 0.1 logMAR or better before and after treatment. No eye showed a decrease in BCVA. Two eyes of one patient had an epithelial ingrowth, which was removed in one case. Follow-up results showed no major complications and no progression of corneal ectasia. CONCLUSION: Early results showed that under-the-flap CXL with excimer laser correction is an effective treatment for early hyperopic keratectasia, with the advantage of rapid recovery, postoperative corneal stability, and no epithelial healing complications. The procedure seems to bear a risk for postoperative epithelial growth into the flap interface.

Third- and fourth-generation formulas for intraocular lens power calculation before and after phakic intraocular lens insertion in high myopia.

PURPOSE: To determine the effect of Visian Implantable Collamer Lens phakic intraocular lens (pIOL) insertion on biometric parameters and IOL power calculation. SETTING: Beirut Eye and ENT Specialist Hospital, Beirut, Lebanon. DESIGN: Prospective case series. METHODS: The IOLMaster 500 biometer was used to measure axial length (AL), keratometry (K), and anterior chamber depth (ACD) values before and 2 months after pIOL implantation. The IOL power was calculated using third-generation formulas (SRK/T, Holladay 1, Hoffer Q) and fourth-generation formulas (Haigis, Barrett Universal II). RESULTS: The study comprised 24 eyes (12 patients). The preoperative and postoperative AL were comparable (27.35 mm ± 1.51 [SD] versus 27.36 ± 1.6 mm; P = .91), as were the K values. There was a significant difference between the preoperative and postoperative ACD (3.67 ± 0.46 mm versus 3.4 ± 0.56 mm; P = .008). The mean IOL power calculation did not change significantly using the Haigis (10.04 ± 3.42 diopters [D] versus 10.1 ± 3.59 D; P = .69), SRK/T (9.85 ± 3.41 D versus 9.94 ± 3.58 D; P = .44), Holladay 1 (9.70 ± 3.47 D versus 9.80 ± 3.64 D; P = .45), Hoffer Q (9.70 ± 3.40 D versus 9.85 ± 3.59 D; P = .37), or Barrett Universal II (9.29 ± 3.52 D versus 9.35 ± 3.71 D; P = .63) formula. CONCLUSIONS: Phakic IOL insertion did not affect IOL power calculation. If preoperative data are not available, postoperative values can be used in IOL calculation formulas.

Inducing fibrogenesis and new interfibrillary bonds in post-laser in situ keratomileusis keratectasia.

Flap creation weakens the cornea and is a risk factor for keratectasia after laser in situ keratomileusis (LASIK). We describe a new technique to halt the progression of keratectasia by mechanically reintegrating the flap into the residual stroma. Deep stromal vertical puncturing is performed in the 4.0 to 9.0 mm paracentral corneal zone at a depth of 350 to 420 µm. The puncturing is applied in circumferential rows using a 25-gauge needle or a diamond blade, with denser puncturing at the level of the cone. In 5 eyes with worsening post-LASIK keratectasia, improved uncorrected and corrected visual acuities, corneal flattening, and a hyperopic shift were observed. There was no progression of keratectasia on serial topographies. New collagen fibrogenesis was documented by optical coherence tomography. The technique seems to be promising to halt the progression of post-LASIK keratectasia. More clinical data and longer follow-up are needed for validation.

Toric ICL Implantation After Sequential Intracorneal Ring Segments Implantation and Corneal Cross-linking in Keratoconus: 2-Year Follow-up.

PURPOSE: To evaluate 6-month and 2-year safety and clinical outcomes of Visian toric Implantable Collamer Lens (toric ICL) (STAAR Surgical, Monrovia, CA) implantation for the treatment of residual refractive errors after sequential intracorneal ring segments (ICRS) insertion and cross-linking (CXL) in keratoconus. METHODS: This consecutive case series included the results of a three-step ICRS-CXL-toric ICL procedure in 16 eyes of 13 patients with moderate to severe keratoconus (stages II and III of Amsler-Krumeich classification). The ICRS and CXL procedures were performed sequentially with an interval of 4 weeks and the toric ICL implantation was performed at least 6 months after CXL. Data were collected preoperatively, at 6 months after sequential ICRS-CXL, and at 6 and 24 months following toric ICL implantation. All 16 eyes were evaluated at the 2-year follow-up. RESULTS: There was a significant decrease in keratometry (steep, flat, and maximum) and refraction (sphere and spherical equivalence, but not cylinder) and a significant increase in both uncorrected (UDVA) (from 1.06 to 0.76 logMAR, P = .004) and corrected (CDVA) (from 0.42 to 0.26 logMAR; P = .002) distance visual acuity 6 months following sequential ICRS-CXL, whereas UDVA and refraction significantly improved 6 months after ICL insertion (UDVA reached 0.33 logMAR, P = .001). At the 24-month follow-up, UDVA and keratometric readings were stable, whereas CDVA, sphere, and cylinder showed a significant improvement. CONCLUSIONS: Implantation of Visian toric ICL following sequential ICRS insertion and CXL is an effective and safe option for correcting high residual refractive error and improving visual acuity in patients with moderate to severe keratoconus in the long term. [J Refract Surg. 2017;33(9):610-616.].

Limbal Stem Cell-Sparing Corneoscleroplasty with Peripheral Intralamellar Tuck: A New Surgical Technique for Keratoglobus.

PURPOSE: To describe the technique of limbal stem cell-sparing corneoscleroplasty for the management of advanced keratoglobus. METHODS: A patient with bilateral advanced keratoglobus, with best-corrected visual acuity of 20/400 in the right eye and 20/200 in the left eye, underwent limbal stem cell-sparing corneoscleroplasty of the right eye. Initially, a 360-degree limbal incision with 200-µm depth was created, followed by a sublimbal tunnel dissection into the sclera, in order to conserve stem cells. Next, a limbus-to-limbus lamellar keratectomy at 200-µm depth was performed. Meanwhile, a donor corneoscleral button with preserved endothelium of the central 8 mm was fashioned. Prior to suturing the donor corneoscleral graft using a modified suturing technique to cover its scleral component, a full-thickness trephination of 8-mm diameter was completed in the central host cornea. RESULTS: Reepithelialization occurred within the first week. No episodes of rejection, intraocular pressure spikes, or epithelial breakdown were observed postoperatively. At the 6-month follow-up, the patient had 20/70 best-corrected vision and a smooth cornea with regular astigmatism on topography. CONCLUSION: Limbal stem cell-sparing corneoscleroplasty is a single-step technique for restoring the structural integrity of the cornea in advanced keratoglobus while preserving the host limbal stem cells.