Limited Visual Potential Research Articles

Excimer Laser Phototherapeutic Keratectomy for Anterior Corneal Opacification After Descemet Membrane Endothelial Keratoplasty.

The aim of this study was to assess the long-term outcome of excimer laser phototherapeutic keratectomy (PTK) for treating remaining anterior corneal opacities after Descemet membrane endothelial keratoplasty (DMEK). This cohort study analyzed 67 eyes of 66 patients undergoing PTK in addition to and after DMEK between 2012 and 2021 at the Department of Ophthalmology, University of Cologne. Patients who were treated by PTK after previous DMEK on the same eye were included. The outcome parameters were best corrected visual acuity (BCVA), changes in refraction, endothelial cell density, corneal densitometry, central corneal thickness, and total corneal higher order aberrations. Patients with visual limitations in addition to anterior opacification were analyzed separately for their visual outcome. Eyes with severe visual limitations that have a very limited visual potential were excluded from the study. In addition, patients with not at least 1 postoperative follow-up examination were excluded from the study. In this study, 67 eyes of 66 patients met all inclusion criteria. The median follow-up period was 13.1 (quartiles: 4.1; 30.7; interquartile range 26.6) months. The mean (±SD) BCVA improved from (logarithm of the minimum angle of resolution) 0.54 (±0.32) to 0.38 (±0.27) at the first postoperative visit ( P < 0.001) and remained significantly improved at all follow-up examinations compared with preoperative BCVA. Refraction and endothelial cell density did not change significantly after PTK. There was a significant decrease in corneal backscatter in the anterior corneal layer ( P < 0.001), and the total higher order aberration ( P = 0.02) and central corneal thickness were significantly reduced at the most recent postoperative visit ( P < 0.001). No immune reactions were observed. Excimer laser PTK after DMEK for persisting anterior corneal opacities has the potential to significantly improve patients' vision without affecting refractive parameters or endothelial cell density.

Cyclophotocoagulation - current applications and practical aspects

Despite the advent of a large variety of minimally invasive glaucoma surgery (MIGS) techniques cyclophotocoagulation (CPC) remains a popular treatment option to lower intraocular pressure (IOP) in glaucoma patients. Guidelines for glaucoma treatment point to the rather unphysiological mode of action and, thus, recommend CPC mainly for refractory glaucoma and/or eyes with limited visual potential. The primary target of CPC is the pigmented secretory ciliary body epithelium resulting in a decreased production of aqueous humor. In addition, an increase of aqueous outflow may contribute to the IOP lowering. CPC is generally considered a low risk intervention. However, macular edema, prolonged intraocular inflammation, vision loss, hypotony, pain or phthisis occur at considerable rates. Over the past decades new promising modes of cyclophotocoagulation have evolved aiming at reducing the risk of adverse effects and improving the efficiency. This article provides an overview of the different currently available cyclophotocoagulation modes: Besides the classic transscleral continuous-wave cyclophotocoagulation it covers endoscopic cyclophotocoagulation, micropulse transscleral laser treatment and transscleral controlled cyclophotocoagulation. Various practical aspects of the treatment in light of the current literature are being discussed.

An update on continuous-wave cyclophotocoagulation (CW-CPC) and micropulse transscleral laser treatment (MP-TLT) for adult and paediatric refractory glaucoma.

Continuous-wave cyclophotocoagulation (CW-CPC) is often preferred to medical and surgical treatments for managing refractory glaucoma. This review summarizes diode CW-CPC indications, history, histopathology, methods, efficacy and safety. It also provides an overview of the latest data available on micropulse transscleral laser treatment (MP-TLT) that uses repetitive micropulses of diode laser energy in an off-and-on cyclical fashion. A literature review was conducted on transscleral CW-CPC (CW-TSCPC), endoscopic CPC (ECP) and MP-TLT. Relevant series of adult and paediatric patients were included for assessing the procedures. Regarding CW-TCPC, highly variable success rates are reported in the literature, depending on the definition of success, type of underlying glaucoma, energy settings, follow-up duration and retreatment rates. CW-CPC often needs to be repeated, especially in paediatric patients. CW-CPC exposes to risks of inflammation and chronic ocular hypotony or phthisis with irreversible visual loss. CW-TSCPC has mainly been used in very severe forms of glaucoma, in painful eyes with limited visual potential or after filtering surgery failure. Published data on ECP are more limited but overall good success rates have been reported. Through the direct visualization of the targeted ciliary body in anatomically abnormal eyes, ECP is the preferred surgical procedure in paediatric refractory glaucoma. Complication rates are relatively low after ECP; however, large studies with long-term follow-up are needed. ECP may be used in difficult, refractory cases, but it is often used earlier when combined with cataract surgery. Despite limited data on the exact mechanism of action of MP-TLT and a lack of standardization of laser settings, the first data from heterogeneous case series shows that it has a similar efficacy and a better safety profile compared to CW-TSCPC in the medium term. Although they may lead to sight-threatening complications, both CW-TSCPC and ECP seem effective. ECP appears to be superior to CW-TSCPC in paediatric refractory glaucoma. Unlike ECP combined with cataract surgery, evidence supporting a wider use of CW-TSCPC and MP-TLT in earlier stages of neuropathy is lacking. While it now appears that the safety profile of MP-TLT is superior to that of CW-CPC, robust prospective comparative studies including homogeneous and well-defined cohorts of patients are still needed to confirm an at least comparable efficacy in the long term.

Removal of calcific band keratopathy without ethylenediaminetetraacetic acid (EDTA) in eyes with limited visual potential.

PurposeTreatment of calcific band keratopathy (CBK) is commonly performed with ethylenediaminetetraacetic acid (EDTA), but EDTA has become more difficult to obtain. This paper describes a technique for treating CBK using a diamond-dusted burr without EDTA in eyes with limited visual potential.Patients and methodsIn this paper, we provide detailed instructions on how to perform the surgical technique for treating CBK, along with a surgical video. We performed a retrospective review of consecutive patients with clinically significant CBK who underwent this procedure from December 2012 to July 2015.ResultsSeven eyes of six patients were included for analysis. Preoperatively, all patients suffered from ocular discomfort. All eyes had poor preoperative visual acuity due to non-corneal ocular disease. The most common causes of CBK in this series were retinopathy of prematurity (three eyes) and chronic uveitis (two eyes). Postoperatively, all patients reported partial or complete relief of discomfort. The length of follow-up ranged from 15 days to 31 months. Two eyes experienced recurrence of CBK. This occurred at 4 and 28 months after treatment.ConclusionThe diamond-dusted burr can easily and effectively remove the corneal epithelium and underlying calcium deposits. Therefore, it may be used to effectively treat discomfort from CBK.

Micropulse Cyclophotocoagulation: Initial Results in Refractory Glaucoma

The purpose of this study is to evaluate the use of micropulse transscleral cyclophotocoagulation (MP-TSCPC), a new and increasingly popular treatment, in patients with uncontrolled glaucoma. A retrospective chart review was performed for all patients who underwent a MP-TSCPC at the Glaucoma Associates of Texas. A total of 84 eyes were treated with MP-TSCPC in this study with a mean follow-up time of 4.3 months. The mean age of treated patients was 74 years and 48 (57%) were female. Preoperatively, mean intraocular pressure (IOP) was 27.7 mm Hg and mean number of ocular antihypertensive medications used was 3.3. Mean postoperative IOP at months 1, 3, 6, and 12 were lowered to 16.3 mm Hg (41.2% reduction), 14.6, 13.0, and 11.1 mm Hg, respectively. Postoperative ocular antihypertensive medication use was also lowered to 1.9, 2.0, 2.0, and 2.3 medications at months 1, 3, 6, and 12, respectively. Five patients required further laser or surgical intervention for adequate IOP control. Complications included hypotony, IOP spike, hyphema, serous choroidal detachment, persistent inflammation, and vision loss. At 3 months, inflammation was still present in 46% of eyes and vision loss of at least 1 line was present in 41% of eyes. MP-TSCPC is effective at lowering IOP and decreasing the need for ocular antihypertensive medications. Eyes with limited visual potential or at high risk for incisional glaucoma surgery can successfully be treated with MP-TSCPC as a reasonable and effective alternative to traditional CPC. These results present short-term data and both longer follow-up and further studies are necessary.

Descemet membrane endothelial keratoplasty for graft failure following penetrating keratoplasty.

Descemet membrane endothelial keratoplasty (DMEK) is superior to penetrating keratoplasty (PK) in terms of visual rehabilitation, intraoperative safety and risk of rejection. Therefore, it seems reasonable to perform DMEK in eyes with endothelial failure following PK. We herein report our first clinical results. Nineteen eyes with endothelial graft failure following PK were treated with DMEK. The majority of these eyes (12) had limited visual potential. The major indication for DMEK was pain relief in patients with bullous keratopathy. Visual acuity (VA), central corneal thickness (CCT), rate of graft dislocations, graft survival, graft rejections and other complications were extracted from the medical records. Although comorbidities limiting VA were present in 12 of the 19 eyes, VA increased from 0.05 to 0.1 (median) in 16 eyes. CCT decreased substantially (range 63-363μm). Rebubbling was necessary in five eyes with incomplete graft adherence. There were two immunologic graft reactions and three graft failures. No major complications like endophthalmitis or expulsive bleeding occurred. DMEK is feasible to treat endothelial graft failure following PK. This is even true for eyes with limited visual potential.

When Should We Give Up Filtration Surgery: Indications, Techniques and Results of Cyclodestruction.

Cyclodestructive procedures are traditionally used in cases of glaucoma that are refractory to medical and surgical therapy. The goal of this chapter is to describe the indications, contraindications, techniques, and pitfalls of cyclodestructive procedures, including transscleral cyclophotocoagulation (TCP), micropulse TCP (MP-TCP), endoscopic cyclophotocoagulation (ECP), and ultrasound cilioplasty. A literature search for cyclodestructive techniques was performed, and relevant studies were included for evaluation and review. It is encouraging that TCP seems relatively efficacious even for patients who have been refractory to other treatments, depending on the energy setting, follow-up period, and definition of success. Repeated TCP is often required. TCP was more often used in eyes with limited visual potential caused by severe forms of glaucoma than in eyes with good visual potential. Serious complications were significant vision loss, inflammation, hypotony, and phthisis. ECP came later into clinical use for the treatment of refractory glaucoma. ECP is able to specifically target the ciliary epithelium under direct viewing as compared to TCP, which is an indirect cyclodestructive procedure. In the literature, it has been demonstrated that ECP has overall good success with relatively low complication rates when used for adult forms of glaucoma. A new technology using MP-TCP is a promising alternative to conventional cyclophotocoagulation. Early evidence shows that MP-TCP has clinical utility and a good safety profile. Ultrasound cilioplasty is a possible alternative to laser cyclodestruction that is already being commercialized and is currently under investigation. Both TCP and ECP are effective cyclodestructive procedures and alternatives for the treatment of glaucoma refractory to medical and surgical therapy, though potential for serious complications exists. TCP, ECP, and ultrasound cilioplasty are being used increasingly as the primary surgery for various kinds and stages of glaucoma.

Correlation between visual acuity and interface reflectivity measured by pentacam following DSAEK

Descemet-stripping automated endothelial keratoplasty (DSAEK) is an advanced method of lamellar endothelial keratoplasty. In comparison with penetrating keratoplasty, visual rehabilitation seems to be faster. Final visual outcome of DSAEK, however, seems to be limited, especially in comparison with Descemet membrane endothelial keratoplasty (DMEK). DSAEK cases without graft failure often do not show any definite correlate for the reduced optical performance. In this study, we tried to correlate visual acuity following DSAEK with interface reflectivity as measured by a rotating Scheimpflug system. We examined 14 eyes of 13 patients with the pentacam for 2-11 months following DSAEK. Reflectivity of the interface region in the centre of the optical axis as well as central corneal thickness was determined. Statistical correlation between interface reflectivity and best spectacle-corrected visual acuity, central corneal thickness and follow-up time was drawn (multifactorial linear regression analysis). Statistically significant correlation between interface reflectivity and BSCVA as well as follow-up time was found. Reflectivity was highest in regions of interface (metal) particles. There was no statistically significant correlation between interface reflectivity and central corneal thickness. We present a measurable correlate for reduced visual outcome following DSAEK despite a clear graft. Inverse correlation between interface reflectivity and best spectacle-corrected visual acuity (BSCVA) indicates that irregularities or scarring in the interface region may influence the optical quality following DSAEK.

Update on results and complications of cyclophotocoagulation

This review highlights recently published studies on transscleral and endoscopic diode cyclophotocoagulation (TCP, ECP) and summarizes the treatment results and complications. Although both TCP and ECP are efficacious procedures for the treatment of refractory glaucoma, no consensus exists for optimum treatment protocol. TCP has mainly been used as a last-resort treatment for intractable glaucoma with very limited visual potential. Repeated treatment is often required. Serious complications include vision loss, hypotony, and phthisis. High treatment energy per session and underlying abnormality seem risk factors for these complications. Recent growing numbers of investigations are giving promising results for TCP as a primary surgery in eyes with good vision. Although ECP came later into clinical use for glaucoma treatment, it is becoming more accepted and no longer reserved for end-stage cases. ECP is most commonly performed in conjunction with cataract surgery and shows overall good success with relatively low complication rates. Serious complications include hypotony, phthisis, cystoid macular edema, and retinal detachment. Recent literatures suggest that both TCP and ECP are performed increasingly as the primary surgery for various types and stages of glaucoma. Both treatments are effective procedures, although potential for serious complications exists.

Special Considerations for Pars Plana Tube-Shunt Placement in Boston Type 1 Keratoprosthesis

The Boston type 1 keratoprosthesis has been successfully used in eyes with a poor prognosis for a conventional penetrating keratoplasty. The Boston Type 1 Keratoprosthesis Study Group reported significant postoperative vision improvement with a high rate of graft retention. However, glaucoma has significantly limited visual potential in patients with otherwise successful transplants. Given a crowded anterior chamber, scarring, and/or inability to visualize the anterior segment after the keratoprosthesis implantation, vitrectomy and pars plana tube placement is frequently necessary for intraocular pressure control. In addition, the need for optimal contact lens fitting after surgery necessitates a modified surgical technique for the combined procedure to avoid complications and to achieve optimal visual rehabilitation. We present our technique in a case series of combined vitrectomy and pars plana glaucoma shunt placement for the Boston type 1 keratoprosthesis.

Early Outcomes of Descemet Stripping Automated Endothelial Keratoplasty in Pseudophakic Eyes With Anterior Chamber Intraocular Lenses

To evaluate complications and clinical outcomes of Descemet stripping automated endothelial keratoplasty in eyes with preexisting anterior chamber intraocular lenses. Retrospective review. Thirty-one patients who underwent Descemet stripping automated endothelial keratoplasty and who had a preexisting anterior chamber intraocular lens were identified from May 2006 through March 2009. Patient follow-up ranged from a minimum of 1 month up to 30 months. Preoperative and postoperative best spectacle-corrected visual acuity, manifest refraction, comorbid conditions, and complications were recorded. Endothelial cell loss, graft dislocation, graft failure rates were calculated. The mean age at surgery was 78 ± 9 years (range, 53 to 91 years). All eyes had pseudophakic bullous keratopathy, except 1 patient who had a failed penetrating keratoplasty graft. Excluding those patients with severely limited visual potential because of noncorneal pathologic features, the mean best spectacle-corrected visual acuity improved significantly from 20/200 to 20/400 before surgery to 20/63 at 3 months (P < .0001), 20/60 at 6 months (P = .0006), 20/50 at 12 to 15 months (n = 10; P = .004), and 20/40 between 23 and 30 months (n = 8; median, 25 months; P = .007). The preoperative mean spherical equivalent was -0.3 ± 1.8 diopters compared with -0.15 ± 1.5 diopters after surgery (P = .78). The graft dislocation rate was 13%, and the graft failure rate was 16%. For those patients with endothelial cell density data available, the average endothelial cell loss was 48% at a mean of 14 months. Although Descemet stripping automated endothelial keratoplasty surgery in patients with an anterior chamber intraocular lens remains a controversial topic, the visual and anatomic outcomes from this limited study support this approach as a surgical option in selected cases.

Endoscopic and Transscleral Cyclophotocoagulation for the Treatment of Refractory Glaucoma

Cyclophotocoagulation (CPC) is traditionally used in cases of glaucoma that are refractory to medical and surgical therapy. The goal of this review is to provide an update on the methods, efficacy, complications, indications, and histopathology of transscleral and endoscopic CPC. A literature review was conducted for transscleral and endoscopic CPC. Relevant studies were included for evaluation of the procedures. For transscleral CPC (TCP), there is a wide range of success rates reported in the literature, depending on energy settings, follow-up period, and definitions of success. Repeat TCP is often required. Serious complications have included significant vision loss, hypotony, and phthisis. TCP has mostly been performed in very severe forms of glaucoma, in eyes with limited visual potential, or after filtration surgery has failed, although more recently TCP has been used as a primary surgery in eyes with good visual potential. There are more limited published results on endoscopic CPC (ECP), which have demonstrated overall good success. Complication rates are relatively low with ECP, however, large studies with long-term follow-up are lacking. ECP has also been used in difficult, refractory cases, but often used earlier when combined with cataract surgery. Both TCP and ECP are effective surgeries with potential for serious complications. Recent studies suggest they may be used increasingly as the primary surgery for various stages of glaucoma.

Indications for and outcomes of penetrating keratoplasty performed by resident surgeons

PurposeTo analyze the indications for and outcomes of penetrating keratoplasty (PKP) performed by resident surgeons at both county hospital and Veterans Affairs facilities. DesignObservational case series MethodsRetrospective review of 79 eyes from 61 patients undergoing PKP from January 1, 1997, through December 31, 2001, to determine indications for surgery and outcomes, including graft clarity and final visual acuity. ResultsThere were 52 (65.8%) primary and 27 (34.2%) repeat transplants performed. Follow-up after surgery averaged 21.9 months. Indications for PKP included failed graft, 23 (29.1%), bullous keratopathy, 17 (21.5%), keratoconus, 16 (20.3%), corneal scar, 15 (19.0%), corneal perforation from infection, 5 (6.3%), and Fuchs endothelial dystrophy, 3 (3.8%). Twenty-one eyes had pre-existing ocular disease limiting final acuity. Overall, 51 grafts (64.6%) remained clear. More primary than repeat grafts remained clear (75% vs 44.4%, P = .012) and achieved 20/40 or better final acuity (30.8% vs 11.8%, P = .05). Excluding failed grafts or eyes with limited visual potential, final acuities achieved were: 19 (47.5%) 20/40 or better, 18 (45%) 20/50 to 20/150, 3 (7.5%) 20/200 or worse. Grafts remaining clear by indication were: failed graft, 9 (39.1%); keratoconus, 14 (87.5%); bullous keratopathy, 13 (76.5%); corneal scar, 10 (66.7%); corneal perforation, 2 (40%); Fuchs, 3 (100%). Eyes achieving final acuity of 20/40 or better by indication were: keratoconus, 9 (56.2%); failed graft, 3 (13%); bullous keratopathy, 3 (17.7%); corneal scar, 2 (13.3%); corneal perforation, 0 (0%); Fuchs, 2 (66.7%). ConclusionsCounty hospital and Veterans Affairs facilities provide a challenging subset of patients for penetrating keratoplasty. Failed graft was the leading indication for transplantation for our population. Graft clarity and final visual acuity varied by indication for transplantation. Resident surgeons can achieve favorable results for penetrating keratoplasty performed at these venues, especially for primary transplants.