35 Posterior Segment Complications of Anterior Segment Surgery
35.1 Postoperative Endophthalmitis
Infectious endophthalmitis following ocular surgery is an uncommon clinical entity that often causes severe visual loss. 1 Pseudophakic endophthalmitis is the most frequently encountered postoperative endophthalmitis category in reported series, as would be expected because more than 1.8 million cataract operations were performed on Medicare beneficiaries alone in 2010. 2 Other types of intraocular surgery, such as secondary intraocular lens (IOL) implantation, corneal transplant, pars plana vitrectomy (PPV), and glaucoma filtering surgery, may also lead to endophthalmitis but are less frequent in clinical series. 3 , 4 , 5
The overall incidence of postoperative endophthalmitis has decreased over a 10-year period from 0.05–0.37% to 0–0.11% (Table 35-1). 6 , 7 , 8 The incidence of endophthalmitis after penetrating ocular trauma is much higher and ranges from 0 to 30% in reported trauma series. 9 , 10 , 11 , 12 A number of clinical factors are associated with a higher frequency of endophthalmitis after ocular surgery. 3 , 5 , 13 , 14 , 15 , 16 , 17
Factors associated with higher acute-onset postoperative endophthalmitis incidence
Factors common to all surgical procedures
Active blepharitis or conjunctivitis
Contaminated eye drops
Active systemic infection
Wound leak on POD1a
Inferior bleb location
Longer length of surgery
Use of topical lidocaine gel before povidone
Repeated incisions in surgical limbus with potentially poor wound healing
Lacrimal drainage system obstruction
Contact lens wear
Immune deficiency (e.g., diabetes mellitus, immunosuppressive medications)
Use of adjunctive antimetabolites
History of bleb infection
Topical corticosteroid use
Suture manipulation or dehiscence
aPostoperative day 1.
35.1.1 Clinical Features and Diagnosis
The diagnosis of postoperative endophthalmitis is made by recognition of clinical features and microbiologic confirmation. The characteristic clinical feature of endophthalmitis after cataract surgery is marked intraocular inflammation (Fig. 35-1), often with fibrin in the anterior chamber (AC) and hypopion. 1 Conjunctival congestion, corneal edema, and lid edema are common associated signs. Symptoms often include pain and marked loss of vision. The loss of vision is usually profound and out of proportion to the typical postoperative vision measured during the first days or weeks after intraocular surgery.
Pain is present in the majority of patients with postoperative endophthalmitis but may be minimal or absent, especially when the endophthalmitis is caused by less virulent organisms.
The symptoms of acute-onset endophthalmitis historically occur during the first postoperative week; however, there is a tendency toward later occurrence (mean: 13 days postoperatively in one study) following clear cornea cataract surgery. 13 , 18
When a clinical diagnosis of endophthalmitis is made, confirmation by microbiologic growth from intraocular specimens is attempted. Vitreous specimens are more likely to yield a positive culture result than are simultaneously obtained aqueous specimens. 19 An AC specimen is often obtained; a syringe with a 30-gauge needle is usually effective because aqueous is easily obtained, in contrast to vitreous. Two different techniques are utilized to procure vitreous specimens; either a needle tap or a vitrectomy (cutting–aspirating) instrument. In the needle tap technique, a 21- to 23-gauge needle is generally introduced through the pars plana and directed toward the midvitreous cavity. Neither a conjunctival incision nor a suture closure is necessary for the needle entry site. The vitrectomy cutter is used when the vitreous sample is obtained in an operating room setting, but some authors have described using a portable, in-office unit. The undiluted aspirate is collected through a syringe interposed proximally in the aspiration line. A small specimen (0.2–0.5 mL) is obtained and inoculated into culture media. If the diluted vitrectomy cassette is to be submitted, the specimen may be passed through a membrane filter system to concentrate the microorganisms on the filter paper. With sterile techniques, the filter paper sections are placed on appropriate culture media, into thioglycolate broth, and on slides for Gram stain. 20 There is a higher chance of achieving a positive culture using the vitrectomy cassette after PPV compared to a vitreous tap. 19 , 21
The recommended culture media include blood agar, chocolate agar, Sabouraud’s agar, Lowenstein-Jensen’s agar, and anaerobic media 22 (Table 35-2). If these are not available, the freshly collected vitreous specimen can be injected directly into blood culture bottles for analysis. Agar-based conventional media or blood culture bottles carry satisfactory sensitivity of microorganism detection with diluted or undiluted vitreous samples, but the culture yield increases when both techniques are combined. 19 , 20 , 21 , 23 , 24 , 25 , 26 , 27 The polymerase chain reaction (PCR) technique has emerged as a promising new development for microbiologic diagnosis in endophthalmitis due to its very high sensitivity even with very limited sample quantity and faster results than conventional culture methods. 28 The intrinsic low specificity carried by this technique might be surpassed with additional PCR-based tests (e.g., in situ hybridization).
When the microbiology staff is not available to process the vitreous specimen in the standard way, blood culture bottles are particularly useful substitute for standard culture plates.
The source of the infecting organisms causing postoperative endophthalmitis is commonly the patient’s flora from the lids, conjunctiva, and periocular tissues. 29 The American Academy of Ophthalmology “Cataract in the Adult Eye” Preferred Practice Patterns guidelines acknowledge this finding by reinforcing the necessity to follow stringent surgical site preparation before eye surgery—which includes application of 5% povidone iodine to the conjunctival cul-de-sac, periocular skin preparation with 10% povidone iodine, and careful sterile draping of the eyelid margins and eyelashes—to reduce resident flora. 30
35.1.2 Management and Course: The Endophthalmitis Vitrectomy Study
The Endophthalmitis Vitrectomy Study (EVS) was a randomized prospective clinical trial evaluating treatment strategies for acute-onset endophthalmitis following cataract surgery or secondary IOL surgery. 31 , 32 , 33 , 34 Two management issues were investigated: immediate three-port PPV versus immediate tap/biopsy and the value of intravenous antibiotics (amikacin and ceftazidime) administered for a minimum of 5 days.
The EVS entry criteria are listed in the following text box. A double randomization scheme allowed four groups for analysis: immediate three-port PPV with intravenous antibiotics, immediate three-port PPV without intravenous antibiotics, immediate tap/biopsy with intravenous antibiotics, and immediate tap/biopsy without intravenous antibiotics. 31 All groups received intravitreal injections of vancomycin and amikacin along with subconjunctival injections of vancomycin, ceftazidime, and dexamethasone at the time of vitrectomy or vitreous tap. Ceftazidime has been widely substituted for intravitreal amikacin due to potential retinal toxicity and microbiologic sensitivity considerations. 21 , 35 , 36 , 37 Furthermore, all groups also received topical vancomycin, amikacin, and prednisolone acetate postoperatively. The value of subconjunctival injections has been questioned 38 , 39 and the authors no longer administer subconjunctival antibiotics and dexamethasone routinely.
EVS entry criteria
Clinical diagnosis of endophthalmitis within 6 weeks of cataract surgery or secondary IOL implantation
Hypopyon or clouding of AC or vitreous media sufficient to obscure clear visualization of second-order retinal arterioles
Cornea and AC clear enough to visualize some part of iris
Cornea clear enough to allow adequate visualization, possibly to perform PPV
Visual acuity (VA) worse than 20/50 but at least light perception
No serious coexisting diseases that might compromise visual outcomes
The microbiologic results of the EVS demonstrated bacterial growth in 69.3% of intraocular cultures. 31 The gram-positive, coagulase-negative micrococci (e.g., Staphylococcus epidermidis) comprised 70% of the EVS isolates. Staphylococcus aureus (9.9%), Streptococcus species (9.0%), Enterococcus species (2.2%), gram-negative organisms (5.9%), and miscellaneous gram-positive organisms (3.1%) occurred less often. All gram-positive organisms were sensitive to vancomycin, but two of the gram-negative organisms were resistant to both amikacin and ceftazidime.
The EVS treatment outcomes demonstrated no difference in final VA or media clarity outcomes whether or not systemic antibiotics were employed (see the following text box). Likewise, if the patient had hand motion or better vision on the initial examination, the EVS showed no difference in these outcomes between the immediate three-port PPV group versus the immediate tap/biopsy group. However, for patients with initial vision of light perception only (26% of patients in the EVS), much better outcomes occurred in the immediate three-port PPV group. On multivariate analysis, the presenting VA was the single most important factor in predicting EVS outcomes regardless of the treatment group.
No difference in final VA or media clarity whether or not EVS systemic antibiotics were employed
For patients with hand motion or better vision, no difference in outcomes between immediate three-port PPV versus tap/biopsy
For patients with initial VA of light perception only, better visual results occurred in the immediate three-port PPV group (vs. tap/biopsy group)
Three times more likely to achieve > 20/40 (33 vs. 11%)
Two times more likely to achieve a 20/100 (56 vs. 30%)
Less likely to incur < 5/200 (20 vs. 47%)
The EVS VA outcomes can be stratified by microbiologic results. 18 , 33 , 34 The best EVS outcomes occurred in the groups with either no or equivocal growth, and in the coagulase-negative Micrococci group. EVS patients with gram-negative organisms had intermediate visual outcomes compared with the “other” gram-positive category (comprised mainly S. aureus and Streptococcus species), which had the poorest outcomes. In the EVS, all cataract surgeries were performed by extracapsular/scleral tunnel phacoemulsification technique. Lalwani et al 18 recently reported remarkably similar VA outcomes and microbiologic results in acute endophthalmitis after clear corneal cataract surgery—VA = 20/40 in 49% (vs. 53% in the EVS), = 20/100 in 71% (vs. 74% in the EVS), and 68% of coagulase-negative staphylococci cases (vs. 70% in the EVS).
The aminoglycosides have a narrow range of safety for intravitreal use during endophthalmitis treatment. Since vancomycin has been shown to cover almost 100% of gram-positive and ceftazidime has been shown to cover more than 90% of gram-negative organisms causing postoperative endophthalmitis, 22 , 36 the authors recommend intravitreal vancomycin and ceftazidime (instead of amikacin) for empirical coverage of organisms in the treatment of clinically diagnosed endophthalmitis.
The EVS evaluated amikacin and ceftazidime for intravenous use. Subsequently, other (possibly better) antibiotic choices (e.g., vancomycin) have become available, but there are no randomized data available to evaluate its use. 40 , 41 , 42 The EVS protocol included fortified topical antibiotics, and these are still generally used by clinicians treating endophthalmitis, but have not been evaluated separately from intravitreal antibiotics for efficacy. Orally administered antibiotics were not evaluated in the EVS. Owing to the lack of supporting evidence regarding the use of systemic antibiotics and the proven efficiency of intravitreal therapy guided by clinical response and culture results, the authors do not routinely use systemic antibiotics via any route in endophthalmitis treatment. Although systemic and even subconjunctival antibiotics are not uniformly used in the treatment of endophthalmitis, the drug dosages used in the EVS and the proper doses to use if the clinician chooses to use them are listed in Table 35-3.
Systemic corticosteroids were used in all patients in the EVS. In the elderly postcataract surgery population, the use of systemic corticosteroids may often be contraindicated because of the high prevalence of diabetes mellitus and other medical conditions precluding the use of systemic corticosteroids. Intravitreal corticosteroids have generally supplanted systemic usage as an adjunct to intraocular antibiotics. 4 The authors recommend intravitreal dexamethasone as a part of the initial treatment in postoperative endophthalmitis (Table 35-3).
There were 10 patients among the 420 patients in the EVS in whom acute-onset postoperative endophthalmitis developed, even though antibiotics were used in the irrigation solution during the cataract surgery. The European Society of Cataract and Refractive Surgery study group has advocated the use of prophylactic intracameral cefuroxime at the conclusion of cataract surgery 49 despite endophthalmitis rates comparable to subsequent publications not supporting this practice. 50 , 51 The use of irrigating solution antibiotics for routine cataract surgery or prophylactic intracameral antibiotics is generally discouraged due to toxicity concerns, risks of contamination when using compounding medication, and the potential to foster the emergence of multiresistant organisms. 52 , 53
35.1.3 Other Postoperative Endophthalmitis Categories
Other postoperative categories include endophthalmitis associated with secondary IOL implantation, penetrating keratoplasty, or vitrectomy. 1 , 3 Because of coexisting ocular pathology, eyes with endophthalmitis after penetrating keratoplasty and PPV may have poorer visual prognoses compared to cases after secondary IOL implantation. Endophthalmitis may also occur following suture removal or manipulation, 16 or late-onset keratitis involving the wound. 54 The removal of 10–0 nylon sutures may facilitate entry of organisms in sufficient quantity through suture tracts to cause intraocular infection. The transition to sutureless cataract surgery has obviated this concern, but it bears consideration in contexts involving suture removal. Delayed-onset keratitis associated with a previous cataract wound may cause breakdown of the wound, allowing entry of organisms. These keratitis-associated cases are often caused by more virulent organisms and generally have a poor visual prognosis. 54
Even though the EVS results apply only to cataract and secondary IOL surgery, some apply the EVS (or EVS-modified) antibiotic treatment regimen (Table 35-3) to other etiologic categories of endophthalmitis, and use a vitreous tap and injection, unless the VA is light perception, in which case vitrectomy is more commonly pursued.
Delayed-onset or chronic postoperative endophthalmitis occurs, by definition, more than 6 weeks after surgery, and is commonly associated with pseudophakia. These patients present with progressive intraocular inflammation and a chronic indolent course. The most frequently reported organisms include less virulent bacteria Propionibacterium acnes, S. epidermidis, and fungi. 55 , 56
The clinical features of delayed-onset endophthalmitis observed on slit-lamp examination may help distinguish between these causative organisms. P. acnes cases are characterized by the presence of a large, white intracapsular plaque associated with chronic granulomatous inflammation that may seem to respond initially to topical corticosteroid treatment (Fig. 35-2). These eyes may have large keratic precipitates on the corneal endothelium and beaded fibrin strands in the AC. In cases caused by S. epidermidis, chronic progressive vitritis is a typical feature, with no white intracapsular plaque.
Fungal endophthalmitis is a commonly overlooked cause of delayed-onset endophthalmitis and should be considered, especially when the clinical response to broad-spectrum antibiotics is poor. The AC may often be relatively quiet initially, but linear, white strands resembling a “string of pearls” may be present in the anterior vitreous, indicating the presence of Candida organisms (Fig. 35-3). Because these organisms generally replicate more slowly, they may seem to respond to topical corticosteroid initially but frequently require vitrectomy combined with intravitreal therapy. 1 Characteristically, a more fulminant course eventually ensues. The efficacy of intravitreal antifungal agents has not been proven as has the efficacy of antibiotics for bacterial endophthalmitis, but intravitreal antifungal agents are generally recommended for suspected fungal endophthalmitis cases. Recommended doses for suspected yeast infections (e.g., Candida) include intravitreal amphotericin B 0.005 mg/0.1 mL or oral fluconazole 200 mg bid 57 ; mold infections (e.g., Aspergillus) are generally resistant to these agents and sequential intravitreal voriconazole injections 0.05 to 0.1 mg/0.1 mL 58 are recommended.
PPV is commonly recommended for cases of delayed-onset endophthalmitis to establish the correct diagnosis by culture, as well as to remove offending organisms and localized foci of infectious material, such as the white intracapsular plaque, when present. Recurrent infection despite vitrectomy may require removal of the entire capsular bag and the IOL, and more prolonged antimicrobial treatment, including reinjection intravitreally. 59 , 60
Endophthalmitis Associated with Filtering Blebs or Glaucoma Drainage Implants
Delayed-onset endophthalmitis can also be associated with conjunctival filtering blebs or glaucoma drainage implants (GDIs). A number of reports show incidence varying between 0.2 and 9.6% following glaucoma filtering surgery. 5 , 61 , 62 , 63 , 64 The offending organisms initially gain access to the bleb (“blebitis”) and subsequently spread to involve the AC and adjacent intraocular structures. Blebitis may respond to periocular and topical therapy without the need for injection of intravitreal antibiotics, but close monitoring is recommended. 65
The clinical features of conjunctival filtering bleb-associated endophthalmitis are similar to those of acute-onset postoperative endophthalmitis. These eyes may present with sudden onset of conjunctival congestion, intraocular inflammation, and pain months or years after previous glaucoma filtering surgery or cataract surgery with an unintentional bleb. The organisms in this category are often more virulent (Streptococcus or gram-negative organisms such as Haemophilus, Pseudomonas, or Serratia species) than the organisms present in other postoperative endophthalmitis categories. 5 , 17 , 61 , 64 Even with prompt treatment, the visual outcomes in this category are generally worse than for acute-onset pseudophakic cases.
Delayed-onset endophthalmitis associated with GDI is a rare event compared to conjunctival filtering bleb-associated endophthalmitis. 66 , 67 , 68 A major risk factor for its development is erosion of the conjunctiva overlying the tube. Manipulation of the tube may also be involved on its pathogenesis. Clinical features and causative organisms are similar to those associated with filtering bleb-associated endophthalmitis. The visual prognosis varies depending on the pathogen(s) involved and preexisting disease from glaucoma. Removal of the GDI at the time of management is controversial. Some cases are treated successfully only with vitreous tap and injection. 69 Prompt surgical conjunctival repair is advised if erosion is identified, and even placement of a patch graft over the tube at the time of the primary GDI procedure may be considered.
35.2 Suprachoroidal Hemorrhage
Suprachoroidal hemorrhage (SCH), also referred to as a hemorrhagic choroidal detachment, may occur during or after any form of intraocular surgery. Reported risk factors for SCH include glaucoma, aphakia, myopia, previous PPV, glaucoma surgery, dropped lens fragments (cataract surgery), phacoemulsification conversion, advanced age, arteriosclerotic cardiovascular disease, diabetes, hypertension, and intraoperative tachycardia. 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 Transient hypotony is a feature common to any intraocular surgery that may leave an eye susceptible to choroidal vascular congestion which, followed by rupture of long or short posterior ciliary arteries, may develop into a SCH. Rhegmatogenous retinal detachment (RRD), scleral buckling, dropped lens fragment, cryotherapy, external drainage of subretinal fluid, and use of aspirin or warfarin are associated with the occurrence of SCH during PPV. 79 , 80 Obstruction of vortex veins with scleral buckling may also predispose to the formation of choroidal effusions.
35.2.1 Clinical Features
The extent of a SCH may range from limited (and inconsequential) to massive (360-degree SCH), forcing the retinal surfaces into apposition in the midportion of the vitreous cavity (“kissing choroidals”); if there is an open wound, extrusion of intraocular contents may ensue (“expulsive choroidals”). Limited SCHs appear as dark gray-brown, dome-like elevations peripherally that have a solid appearance and are immobile. Chorioretinal folds may result from hypotony, and there may be some degree of overlying exudative retinal detachment which might be more visible at the margin of the SCH. Substantial intraocular pressure (IOP) elevation and eye pain are typically associated with the acute development of large SCHs. B-scan ultrasonography will show a relatively thick, dome-shaped elevation with little after movement and variable echogenicity within the suprachoroidal space.
35.2.2 Management and Course
For intraoperative SCH, all ocular incisions or wound leaks should be closed as quickly as possible. Most surgeons recommend removal of vitreous prolapse into the wound (if possible) and some recommend acute drainage of SCH if continued high IOP is present. 70 , 71 , 72 , 78 , 79 , 80 The only goal in pursuing primary intraoperative SCH drainage is to lower IOP sufficiently to avoid central retinal artery occlusion. Thus, intraoperative drainage of SCH should be considered only as a last resort, as the freshly clotted blood usually does not drain well, and lowering of the pressure often merely propagates more bleeding. The use of perfluorocarbon liquid or silicone oil tamponade has been advocated to provide long-term internal tamponade postoperatively. 78 , 81
Drainage may be accomplished by making a full-thickness sclerotomy in any quadrant (preferably in the maximal choroidal elevation quadrant), approximately 4 to 8 mm posterior to the limbus. Generally, it is not necessary to make a drain posterior to the site corresponding to the ora serrata. The sclerotomy should be left open for continued postoperative drainage.
The timing of a secondary surgical intervention for either an intraoperative or postoperative massive SCH is somewhat controversial, but most surgeons recommend waiting 10 to 14 days to allow liquefaction of the SCH, which facilitates draining the hemorrhage. Some case reports demonstrated satisfactory benefit with injection of recombinant tissue plasminogen activator in the suprachoroidal space to induce earlier clot dissolution, 82 , 83 but this rarely seems necessary; further investigation is needed to support its use. Systemic and/or topical corticosteroids along with antiocular hypertensives and analgesics may be necessary during this observation period. Earlier surgical intervention, however, may be warranted for intractable pain or uncontrollable IOP elevation. There are no randomized prospective clinical trials addressing this timing issue because it is a rare problem with complex variables at play.
The surgical objective in treating patients with massive SCH is to drain as much hemorrhage as possible. If there is prolapsed vitreous gel or retinal detachment, vitrectomy is considered; a scleral buckle and/or intraocular gas tamponade are potential adjuncts if there is retinal detachment (Fig. 35-4). 70 , 71 , 72 , 73 Perfluorocarbon liquids may be useful intraoperatively in managing a combined SCH and RRD. 78 , 81 , 84
35.3 Retinal Detachment following Cataract Surgery
Structural changes occur within the vitreous following cataract surgery that are likely initiated by biochemical changes which may lead to progressive syneresis, increased mobility of the vitreous gel, and eventual posterior vitreous detachment. 85 Hypotony might play a role in facilitating vitreous detachment. Acute posterior vitreous detachment is associated with retinal tears and subsequent retinal detachment in a small percentage of patients. 86 , 87 Although the incidence of RRD following cataract surgery is relatively low, it is an important cause of moderate to severe visual impairment consequent to cataract surgery. Patients undergoing cataract extraction should be aware of symptoms that could be indicative of a retinal tear or detachment, such as flashes, floaters, and a progressive loss of peripheral vision.
35.3.1 Clinical Features, Incidence, and Risk Factors
The reported incidence of retinal detachment following cataract surgery ranges from approximately 0.26 to 1.5%. 30 , 88 , 89 , 90 , 91 When patients are followed up for longer postoperative intervals (8–20 years), the incidence has been reported to rise to 2.3%. 92 , 93 A 1991 retrospective study of 338,141 Medicare beneficiaries older than 65 years who underwent various forms of cataract surgery demonstrated incidences in retinal detachment of 1.6% after intracapsular surgery, 0.9% after extracapsular surgery, and 1.2% following phacoemulsification, during a 4-year follow-up period. The same study detected an increase to 5.0% when cataract surgery was accompanied by vitreous loss. 88 Recent studies have shown decreasing incidence of retinal detachment after phacoemulsification 90 , 93 and have corroborated evidence for vitreous loss during cataract surgery as a major factor for the development of retinal detachment after cataract surgery, increasing the risk at least four times. 94 , 95 A case–control study evaluating 63,298 cataract surgeries identified an increased risk for pseudophakic retinal detachment in patients with myopia (3×), RRD in the fellow eye (12×), zonule dehiscence (12×), and male gender (2×). 96 Other risk factors for retinal detachment after cataract surgery include loss of lens fragments into the vitreous cavity, lattice degeneration, younger age (< 60 years old) and white race. 86 , 87 , 88 , 89 , 90 , 91 , 92 , 93 , 94 , 95 , 96 , 97
Another risk factor for retinal detachment that has been cited is the performance of YAG (yttrium–aluminum–garnet) laser capsulotomy. 89 , 93 , 96 , 98 , 99 , 100 , 101 The largest reported study involved Medicare patients who underwent extracapsular surgery in 1986 and 1987 and who were followed up for 1 to 2 years after YAG laser capsulotomy. 100 Overall, patients who underwent posterior capsulotomy were about two times more likely to have either retinal tears or retinal detachment during the follow-up interval. Later studies using a variety of methodologies showed variable but lower RD rates. 89 , 93 , 96 , 101
The risk for retinal detachment after cataract surgery is between 0.26 and 1.5%. When cataract surgery is accompanied by vitreous loss, the incidence of retinal detachment or tear formation may increase more than four times.
35.3.2 Management and Course
The efficacy of prophylactic treatment of peripheral retinal disease before cataract surgery is controversial. While all symptomatic tears are generally treated, asymptomatic horseshoe retinal tears are commonly treated, and atrophic round holes or operculated holes are usually not treated. Likewise, lattice retinal degeneration, present in approximately 7% of the general population, is usually not treated before cataract surgery unless associated with a flap tear. 102
Pneumatic retinopexy is not commonly performed in the early postoperative period following cataract surgery, especially when there is a limited view of the retinal periphery. Primary PPV with or without scleral buckling is more frequently used in these eyes. Sutures may be placed to reinforce the cataract surgery incision in selected patients. Potential complications from pseudophakic retinal detachment surgery include recurrent retinal detachment with proliferative vitreoretinopathy, choroidal detachment, and complications from drainage of subretinal fluid. 103
35.4 Needle Penetration of the Globe
Cataract surgery today is usually performed under topical anesthesia using clear cornea incision and phacoemulsification. This technique obviates the concern of needle penetration of the globe during administration of traditional retrobulbar or peribulbar anesthesia. Because a retrobulbar or peribulbar block results in both deep anesthesia and akinesia, some anterior segment surgeons still prefer the various block techniques.
The Atkinson retrobulbar block employs an elevated and adducted eye position to place the needle tip into the muscle cone adjacent to the optic nerve. Because of the risk for needle entry into either the globe or the optic nerve, many ophthalmologists have adopted a peribulbar block, in which the eye is positioned straight ahead, the needle is directed more peripherally to the globe, and larger volumes of anesthetic are used to fill the orbit. 104 The delineation between peribulbar and retrobulbar is often indistinct. While some advocate a shorter needle than the traditional 1.5-inch, 25-gauge needle (which is not always inserted to the hub), this too is a somewhat artificial permutation because orbit sizes and other anatomic variations require a customized application of anesthetic for individual patients. Many also advocate a flat grind needle rather than the sharp end.
Factors predisposing to needle penetration of the globe include axial high myopia, posterior staphyloma, previous scleral buckling surgery, and poor patient cooperation with the injection. 105 , 106 , 107
35.4.1 Clinical Features
Globe penetration during administration of the anesthesia should be suspected if any unusual resistance is felt by the surgeon during entry or if the IOP is noted to be either very low or very high after the block is given. The loss of the red reflex after the block is given could also indicate a needle penetration. Patients experience severe pain when needle entry of the globe occurs.
Factors that predispose to needle penetration of the globe during administration of a retrobulbar or peribulbar block include axial high myopia, posterior staphyloma, previous scleral buckling surgery, and poor patient cooperation with the injection.
When needle entry into the globe is suspected, the diagnosis can be confirmed by indirect ophthalmoscopy. One or two focal retinal penetration sites may be evident, and some degree of retinal disruption (retinal detachment) and subretinal or vitreous hemorrhage is typically present. Suprachoroidal detachments may also develop.
35.4.2 Management and Course
The early management of posterior segment needle entry wounds is controversial. Most authors recommend prompt laser treatment or retinocryopexy to peripheral visible retinal perforation sites, but blood or lens opacities may preclude a satisfactory view of the area. The patient can be followed up with serial echography examinations for the development of retinal detachment until the vitreous hemorrhage clears. If retinal detachment occurs, early intervention is recommended. The location of the retinal tears along with the type and extent of associated findings (e.g., hemorrhage, choroidal detachment) will determine the specific surgical approach utilized.
The visual prognosis usually depends on the presence or absence of retinal detachment and damage inflicted directly to the posterior pole by the needle. In one report, eyes that had retinal breaks without retinal detachment had a much better visual prognosis than eyes complicated by retinal detachment. In the former category, seven of nine cases without retinal detachment achieved 20/50 or better VA, whereas in the latter category, only 2 of 14 retinal detachment cases achieved 20/400 or better VA. 105