Authors: K Priyadarshini, Namrata Sharma, Manpreet Kaur, Jeewan S Titiyal
Categories: Review Article - Clinical, Cataract, LSCD, Limbal stem cell deficiency, MGD, Meibomian gland dysfunction, Mooren’s ulcer, OCP, OSD, Ocular cicatricial pemphigoid, Ocular surface disease, SJS, Stevens–Johnson syndrome, dry eye disease
Source: Indian Journal of Ophthalmology
Authors: K Priyadarshini, Namrata Sharma, Manpreet Kaur, Jeewan S Titiyal
Cataract surgery, which is the most widely performed ophthalmic procedure, is usually done in the elderly population, who are also prone to ocular surface disorders. Ocular surface diseases are multifactorial in nature and associated with symptoms and signs such as foreign body sensation, burning, fatigue, photophobia, red or watery eyes, or reduced visual acuity. These include a spectrum of conditions that may be immune or non-immune in nature. Cataract surgery in itself is known to alter the normal ocular surface milieu and cause tear film disturbances which can last up to 6 months post-operatively. These symptoms can be exaggerated in patients with ocular surface diseases. The planning and execution of cataract surgery can also be difficult in patients with associated ocular surface diseases. In this review, we discuss the various aspects of planning and intraoperative modifications to optimize the outcomes of cataract surgery in patients with ocular surface diseases.
Cataract surgery is the most commonly performed ophthalmic procedure worldwide, with cataracts being one of the leading causes of reversible blindness globally. Most cataract surgeries are performed in people over 50 years of age, accounting for senile cataracts. Ocular surface disease (OSD), by definition, is a multifactorial disorder associated with related symptoms and signs, such as foreign body sensation, burning, fatigue, photophobia, red or watery eyes, or reduced visual acuity, which is widely prevalent among the elderly population.[1–3] These may be immunological or non-immunological, with immunological diseases requiring additional management by the concerned immunologist/rheumatologist.
The common immunological conditions associated with ocular surface disorders are Stevens–Johnson syndrome (SJS), peripheral ulcerative keratitis (PUK), Mooren’s ulcer, ocular cicatricial pemphigoid, and vernal keratoconjunctivitis. The other non-immune conditions leading to a poor ocular surface are chemical injury sequelae, limbal stem cell deficiency (LSCD), meibomian gland dysfunction (MGD), blepharitis, trachoma sequelae, and degenerative lesions of the cornea such as Salzmann nodular degeneration, pterygium, spheroidal degeneration, etc., The images of various ocular surface diseases which can complicate cataract surgery are given in Fig. 1. The etiology of cataracts in these eyes is likely related to steroid use, chronic inflammation, or age-related.
Gupta et al. report at least one abnormal ocular surface tear test in 80% of patients undergoing cataract surgery, while 40% of them had at least two abnormal tear tests.[4] Zamora et al. have further reiterated in their study that the ocular surface changes and superficial punctate keratopathy worsened post-phacoemulsification surgery.[5] Thus, cataract surgery can worsen the symptoms and signs in eyes with pre-existing OSD. It can also disturb the normal niche of the ocular surface and induce signs and symptoms of dry eye in previously normal eyes. The prevalence of OSDs in those undergoing cataract surgery reported in the literature so far shows a wide variance between 9 and 100%, with symptoms lasting as long as up to 6 months post-operatively.[6–9] Thus, it is imperative to understand the nuances in the planning and execution of cataract surgery in patients with pre-existing OSD. In this review, we aim to highlight the preoperative planning, intraoperative modifications, and post-operative outcomes related to cataract surgery in eyes with OSD.
A literature search was performed using PubMed, Medline, Cochrane Library Database, EMBASE, and Scopus (1960 onward), using the cataract surgery in ocular surface disease, cataract surgery in Stevens–Johnsons syndrome, cataract surgery in ocular cicatricial pemphigoid, cataract surgery in limbal stem cell deficiency, cataract surgery in pterygium, cataract surgery in meibomian gland dysfunction, and cataract surgery in dry eye disease. We found a total of 674 articles including systematic reviews, randomized controlled trials, and retrospective and prospective case series and case reports of which we included 58 studies, which were the most relevant to our discussion.
The preoperative evaluation should include a comprehensive evaluation of lids and adnexa with objective and subjective tests to assess the tear film status.
The assessment of corneal staining helps assess pre-existing punctate keratopathy and impacts further decision making.[10] It helps assess tear breakup time, presence of dellen or conjunctivochalasis, which can cause exaggerated symptoms post-surgery if missed preoperatively due to disturbances in tear film stability.[11] Moderate-to-severe grades of dry eye need further evaluation and optimization of ocular surface before proceeding with cataract surgery. If aqueous tear deficiency is identified, we need to treat it ruling out possible systemic causes with referral to a rheumatologist if required.[12]
Various machines such as LIPIVIEW II, IDRA-ocular surface analyzer, Kanghua dry eye analyzer, Lipiscan Dynamic Meibomian Imager, etc., can help assess the tear film stability objectively. These devices provide us with dynamic meibomian gland imaging, near-infrared surface imaging highlighting the morphology of meibomian glands, lipid layer thickness, blink dynamics and tear film redistribution, non-invasive tear film breakup time, and tear meniscus height. IDRA further helps us analyze whether the tear film instability is the effect of aqueous deficiency or lipid layer deficiency, categorizing the type of dry eye disease.
Schirmer test is another easily available bedside evaluation test to determine the tear film stability. It is an easily doable test in an ophthalmic setup wherein the more recent advancements are unavailable.
There are various reports which have indicated exacerbation of dry eye disease (DED) post-cataract surgery.[4,7,9,10,13] Park et al. further reports exacerbation of meibomian gland dysfunction post-cataract surgery, associated with structural changes of the glands.[14] Incidence of DED was found to be higher in manual small incision cataract surgery in comparison to phacoemulsification.[6,15] Yu et al. further report higher scores of ocular staining in those who underwent femtosecond-assisted cataract surgery in comparison to conventional phacoemulsification.[16] Zamora et al. report worsening of ocular surface disease in patients with pre-existing altered values, which results in prolonged post-operative symptoms.[5] Thus, it is imperative to augment the ocular surface with preferably preservative-free lubricants perioperatively in patients with preoperative values suggestive of tear film instability. Also, adnexal disorders such as MGD, recurrent marginal keratitis, and internal hordeolum should be medically managed before planning cataract surgery.[17] Aqueous tear deficiency can occur as a result of old age, systemic medications, post-menopausal hormonal changes, post-herpetic viral infection, and conjunctivitis and can occur in association with dryness of mouth or pain in small joints which are indicative of rheumatological disorders.[18,19]
The instability of tear film can also hinder preoperative keratometry evaluation in addition to causing post-operative complications such as epithelial defects, corneal melts, infection, and impaired visual outcomes.[12] Use of surface augmentation methods such as preservative-free lubricants, autologous tears, and punctal plugs can help reduce post-operative complications due to DED.[20–24]
The lid margin should be evaluated for presence of entropion, ectropion, trichiatric lashes, fornices shortening, and lid margin keratinization, which are commonly associated with conditions such as SJS syndrome, chemical and thermal injury sequelae, ocular cicatricial pemphigoid, and trachoma sequelae.[25,26] If present, these abnormalities should be addressed first before going ahead with cataract surgery, as these can result in occurrence of non-healing epithelial defects and secondary infections post-operatively.[26,27] Thus, procedures for correction of entropion, ectropion, fornix reconstruction with amniotic membrane and mucous membrane grafting, and lid margin keratin excision with mucous membrane graft should be undertaken prior to cataract surgery to augment the ocular surface.[26–28]
The corneal should be examined for any irregularities, scarring, localized thinning, peripheral vascularization, and signs of limbal stem cell deficiency (LSCD). The source of corneal scarring can be multifactorial and could be suggestive of persistent epithelial defects, which is a sign of LSCD.[26,29–31] The cornea can be affected in degenerative disorders, chemical injury sequelae, post-VKC shield ulcer or secondary infection, SJS sequelae, PUK, Mooren’s ulcer, OCP, etc., The systemic disorders, if not adequately treated with immunomodulators, can result in post-operative sterile corneal melt or necrotizing scleritis.[31]
The irregularities of the cornea can pose challenges in obtaining preoperative biometry for IOL calculation and in intraoperative visibility. Additional procedures such as optical iridectomy/pupilloplasty maybe required in such cases to provide visual rehabilitation during cataract surgery. Preoperative lamellar keratoplasty procedures, tectonic grafts (PUK, Mooren’s ulcer), pterygium excision, phototherapeutic keratectomy, or procedures to address LSCD might be required in these eyes before planning cataract surgery for improving visual outcomes.[32] Post-operative rehabilitation of these eyes with rigid gas permeable lenses or scleral contact lenses may also be required to address the irregular astigmatism which prevails due to corneal irregularities.[33]
Since the cornea accounts for two-thirds of the refractive power of the eye, the keratometry values are subject to change with relative changes in corneal curvatures. In diseases like EMBD and SND, it was found that there was a significant change in keratometry with differences as high as 3.2D in EBMD eyes and 2.2D in SND eyes post-surface augmenting procedures such as superficial keratectomy (SK) and phototherapeutic keratectomy (PTK).[34] Successful pterygium excision can also reverse corneal astigmatism resulting in corneal flattening and significant topographic changes.[35] Thus, any pterygium >2.5 mm into the cornea and those with significant corneal distortion (<2.5 mm) should be addressed first before planning cataract surgery.[36] In cases <2.5 mm extension into the cornea without much corneal distortion, a simultaneous cataract surgery with pterygium excision can be planned. It is ideal to wait for 4–12 weeks till stabilization of keratometry in patients who have undergone procedures to segment ocular surface such as pterygium excision, SK, or PTK before planning cataract surgery.[36]
It is important to address the surface irregularities and tear film abnormalities and associated inflammation before planning cataract surgery in patients with OSD. This can help obtain better biometry and keratometry and thus help in improving visual outcomes. Thus, any corneal procedure or ocular surface procedure should precede cataract surgery and IOL planning. Simultaneous cataract extraction and IOL implantation can be considered in eyes with severe corneal scarring, wherein penetrating keratoplasty is indicated.[36]
In scarred corneas, the average keratometry obtained over the central 3 mm of the cornea is considered for IOL calculation. It can be obtained using video-keratography (VKG) or Scheimpflug imaging. IOL master 700 can also provide reliable biometry values in eyes with OSDs. Though Barrett Universal II can be used for mild–moderate tear film instability, the IOL formulas based on artificial intelligence (AI) algorithms such as Hill-RBF and Kane formula are ideal to calculate the IOL power for rather steep/flat corneas with irregularities due to scarring.[37] In eyes with significant scarring, in which subsequent or simultaneous keratoplasty procedures are planned, standard keratometry values can be used for IOL calculation. When the standard keratometry values are used, the patient should be counseled for requirement of post-operative contact lenses to address the residual astigmatism.
The toricity of eyes with OSD can be dynamic with the progressive changes in ocular surface. So toric IOLs are best avoided in these eyes, unless in certain conditions like pterygium in which the keratometry is unlikely to change. However, a recent study done by Teshigawara et al. showed that preoperative use of topical rebamipide improves the irregular corneal astigmatism, thereby decreasing intrapatient variation in corneal power, thus improving the toric IOL calculation, enabling better predictability of post-operative outcome.[38] This is because rebamipide was known to suppress the inflammatory cytokines and increase mucin-like substances in the tear film, thus stabilizing it.[39] Premium IOLs like multifocals should also be avoided in these patients. In cases where the intraoperative visibility becomes a challenge, and the status of posterior capsule cannot be clearly visualized, it is better to place a three-piece IOL with haptics in sulcus.[12] The patients with risk of further corneal decompensation post-cataract surgery should be counseled for a possible need of keratoplasty for visual rehabilitation post-cataract surgery.[25,30,40]
Patients with ocular surface disease are prone to recurrent inflammation. The changes in their tear film dynamics and corneal irregularities cause visual disturbances with changing astigmatism. The established treatment guidelines should be followed for each condition causing the OSD before cataract surgery. The required preoperative optimization for some common conditions is discussed below.
This includes treatment of multifactorial problems causing the dry eye disease, which might be present as a continuum. This spectrum includes MGD, allergic conjunctivitis, blepharitis, VKC, and other systemic causes such as Sjogren’s syndrome. Thus, the ocular components of allergy need to be addressed with topical antihistamines, mast cell stabilizers, immunomodulators, and preservative-free lubricants, while the systemic component needs management with the help of a rheumatologist. Lid hygiene and hot fomentation, procedural therapies like meibomian gland thermal pulsation and expression, and punctal occlusion are important components in the treatment of MGD and aqueous tear deficiency.[20,41] The treatment of associated infections with topical antibiotics is required to manage blepharitis.[42,43] Thus, the medical management should encircle the infectious, inflammatory, and allergic components of the spectrum to optimize the ocular surface for cataract surgery [Fig. 1f].
The visual acuity in SJS is usually affected due to lid and tear film abnormalities, lid-margin keratinization, corneal scarring, windshield-wiper keratopathy, and persistent epithelial defects due to LSCD.[44] Cataractogenesis in these eyes occur as a result of ongoing inflammation and chronic use of steroids. Cataract surgery in these eyes can be attempted only after the primary manifestations of the disease are addressed. The lid and surface procedures are done first followed by procedures to rejuvenate the limbal stem cells. Once the ocular surface is stabilized, cataract surgery can be performed if that is the main cause of suboptimal visual acuity. The eye needs to be free of inflammation while planning the cataract surgery to obtain favorable outcomes [Fig. 1c].
Ocular cicatricial pemphigoid (OCP) is an immune-mediated cicatricial disease which primarily affects the older people. The main manifestations of this disorder are subepithelial fibrosis, LSCD, symblepharon formation, and surface keratinization.[45] Despite treatment with immunosuppressive drugs, 33% continue to have a low-grade inflammation.[46] Thus, systemic immunosuppression is mandatory in patients with OCP undergoing cataract surgery to control low-grade conjunctival inflammation along with topical steroids and immunomodulators [Fig. 1b]. Systemic immunosuppression with systemic immunomodulators and steroids has been advocated in various studies.[27,47] The lid and adnexal abnormalities such as entropion, ectropion, trichiasis, and symblepharon/ankyloblepharon should be treated before attempting cataract surgery in these patients to minimize post-operative complications.[27]
Mooren’s ulcer is a non-infectious keratitis of autoimmune etiology, chronic in nature, characterized by painful peripheral ulceration of the cornea with multiple exacerbations. The disease sequelae include corneal scarring, neovascularization, irregular astigmatism, and complicated cataract. The major risk in cataract surgery in these eyes is reactivation of the ulcer post-surgery, which has been reported in literature.[48,49] Thus, perioperative systemic and topical immunosuppression has been advocated with pulse intravenous followed by oral steroids in the study done by Sangwan et al.[48] In addition, immunomodulators such as cyclophosphamide can also be used in the long term to prevent recurrence of ulcer post-operatively. However, a recent study by Das et al. showed that 80% cases on maintenance therapy showed recurrence, making the role of maintenance in cases of Mooren’s ulcer questionable.[49] In the study done by Sangwan et al., all eyes were operated after an inflammation-free period ranging from 2 to 11 months, while in the study by Das et al., cataract surgery was done after a disease-free period of at least 6 months.[48,49]
Limbal stem cell deficiency is a common association with many OSDs, most commonly thermochemical injury sequelae and SJS sequelae. It can also be associated with chronic cases of VKC. Long-term use of steroid in these patients can also predispose them to cataractogenesis. There have been few reports of cataract surgery in patients who have undergone limbal stem cell transplant procedures and penetrating keratoplasties and surface augmenting procedure such as amniotic membrane transplant.[50–52] The LSCD should be addressed first to obtain optimal results in patients with associated cataract.
Preoperatively once cataract surgery is planned after optimizing the ocular surface as per the OSD present in the patient, the patient should be prescribed preservative-free antibiotics. Most of these patients are likely to require a peribulbar anesthesia rather than topical anesthesia in view of poor visibility and associated lid and adnexal abnormalities, longer duration of surgery since it is technically challenging and the associated photophobia in these patients.[40] Also, topical anesthetic can further disturb the milieu of the ocular surface, thus augmenting the existing ocular surface problems. Thus, it would be better to avoid topical anesthesia.[36] One should also remember to not irrigate the eye repeatedly and avoid all means of unnecessary surgical trauma. As discussed earlier, phacoemulsification is the surgery of choice in patients with OSD. In eyes with poor visibility with endoilluminator and eyes in which intraoperative complications such as posterior capsular defect occur in early stage, ICCE, ECCE, or MSICS can be done.[40] The important tips and tricks to follow in various steps of phacoemulsification in eyes with OSD have been discussed below.
The incision should be aligned such that the thinned-out areas of the cornea are avoided and the areas of clear cornea are accessible through the phacoemulsification probe. So, the surgeon can cater the incision position to handle the requirements of every individual case either superiorly, temporally, or supero-temporally.[40] A clear corneal incision is ideal in cases where there is cicatrization and scarring of the surrounding conjunctiva. It avoids occurrence of conjunctival ballooning and decreases chances of post-operative conjunctival inflammation.[40] However, in cases of Mooren’s ulcer, a scleral incision maybe preferred since corneal incision was found to cause an immune response to the corneal antigen calgranulin C.[49,53] It is better to avoid epithelial debridement in these cases as much as possible, since wound healing during re-epithelialization may not be as expected in normal eyes. Viscoelastic device can be used for better visualization on the ocular surface. Endoilluminator can also aid in improving visibility during surgery.[30,36]
It is important to stain the anterior capsule with trypan blue dye in all cases to aid in better visualization during capsulorrhexis. Nylon hooks can be used in eyes with poorly dilating pupil to aid better visibility in the areas of clear cornea. While Vasavada et al. recommends regrasping of the rhexis margin frequently, the modified technique by Sharma et al. where the authors insist in regrasping the flap only in areas of relatively clear cornea appears more technically safe and plausible.[40,54] Thus, we should be careful not to leave the grasp of the flap margin in areas which are not visible. Endoilluminators can help enhance visibility at this stage, highlighting the rhexis margin with a shimmering reflex.[40]
The parameters of phacoemulsification such as torsional force, vacuum, aspiration, and irrigation should be kept on the lower side. Phacoemulsification can be done in the iris plane for better visibility, to avoid posterior capsular tear and at the same time not damage the endothelium much.[40] Endoilluminator can enhance visualization at this stage as well, enhancing the visibility of the chopper and helping us in gauging the exact depth during nuclear fragmentation, so as to avoid thin slices of nuclear fragments and prevent posterior capsular rent.[40] It also helps to better visualize the capsulorrhexis margin during IOL insertion.[40]
Optical iridectomy and sphincterotomy should be done in cases in which the clear cornea is decentered, to aid in visual recovery. Whenever in doubt about the wound integrity, it is better to suture the wound in these cases.[36] Early suture removal can be advocated to avoid post-operative astigmatism.
The earliest reported case series of cataract surgery in ocular surface disorders was in 1988 by Sainz de la Maza et al., wherein the authors reported the outcomes of extracapsular cataract extraction (ECCE) done in 26 eyes of patients with ocular cicatricial pemphigoid (OCP).[55] There was a significant improvement in the mean post-operative BCVA, with keratitis occurring in three eyes post-operatively. The occurrence of keratitis is probably due to the long-term immunosuppression which is required in these patients. The outcomes of cataract surgery in various ocular surface disorders have been shown in Table 1.
Cataract surgery has been most reported in eyes with SJS sequelae among all ocular surface disorders, with phacoemulsification being the most commonly performed type of surgery since its introduction.[40,54,56,57] Other procedures like manual small incision cataract surgery (MSICS), extracapsular cataract extraction (ECCE), and intracapsular cataract extraction (ICCE) have been done only in cases, wherein the visibility was too poor, in very hard cataracts, or in cases in which posterior capsular tear occurred intraoperatively. The initial case of cataract surgery in eyes with SJS sequelae was reported by Sangwan and Burman in 2005, in which ECCE was done in three eyes, with improvement in immediate post-operative BCVA ranging between 20/40 and 20/50, which later regressed to 20/100-20/200.[56] Later, Narang et al. reported phacoemulsification done in a retrospective series of 40 eyes, in which there was improvement in BCVA, though ocular surface breakdown was noted in 10% of eyes which was managed appropriately.[57] Sharma et al. in a prospective interventional series of phacoemulsification done in 21 eyes of SJS sequelae report a 9.5% conversion to ECCE and 4.5% conversion to ECCE due to posterior capsular rupture in which the eyes were left aphakic.[40] The reported complications in their series were conjunctival inflammation in 14%, epithelial defect in 9%, and filamentary keratitis in 9% eyes post-operatively, which were medically managed.[40]
Overall, the studies reported so far in literature showed improved visual outcomes after cataract surgery in the immediate post-operative period after good control of ocular inflammation in eyes with concurrent OCP and cataract.[27,47,55] Since the initially reported case series by Sain de la Maza et al., in which ECCE was performed in eyes with OCP, Geerling and Dart report a prospective series in which the patients underwent ICCE, ECCE as well as phacoemulsification.[27] They documented that 50% (2/4) of eyes which underwent ECCE showed early progression of the disease post-operatively, with regression in the initially attained visual acuity in 8/15 eyes.[27] Puranik et al. in his series report a disease progression in 2/9 eyes at the end of 1 year.[47]
There are two case series reported so far in which cataract surgery was done in patients with Mooren’s ulcer. Both the studies show significant improvement in post-operative visual outcomes, with recurrences occurring in some patients (16.7% in the study done by Sangwan et al. and 19.2% in the study done by Das et al.) in the post-operative period up to 7 years.[48,49] Thus, cataract surgery can provide temporary improvement in visual acuity in most patients. However, these cases should be closely monitored for recurrence of the disease post-cataract surgery.
The outcomes of cataract surgery in eyes which have undergone corrective procedures for limbal stem cell deficiency have been reported. Arora et al. report a case in which cataract surgery was done in a patient with limbal stem cell deficiency post-chemical injury sequelae, for which penetrating keratoplasty with simple limbal epithelial transplant was initially done, after which the patient gained a post-operative BCVA of 6/18, maintained till last follow-up.[50] In another case report, Nair et al. document a case in which the patient underwent cataract surgery after a primary SLET was done in an eye with LSCD following chemical injury, in which the patient gained a post-operative visual acuity of 20/60.[51] Das et al. report a case of bilateral phacoemulsification in a chronic case of VKC which underwent pannus excision with AMT for ocular surface augmentation initially, following which the cataract surgery was done with the patient gaining post-operative BCVA of 20/25 in both eyes with scleral lens prosthetic device.[52] Thus, the cases reported so far in literature insist on the timely ocular surface augmentation in cases of LSCD and stepwise management of cataract after optimizing the ocular surface.
Phacoemulsification is thus far the most commonly procedure and best suited for patients with dry eye disease.[58] Donthineni et al. report the outcomes of cataract surgery of 668 eyes in patients with dry eye disease due to various etiologies such as cicatricial conjunctivitis (CC), MGD, and Sjogren’s syndrome (SS).[58] Eyes with both MGD and SS showed better improvement in final BCVA (0.1 logMAR) in comparison with eyes with CC (0.1 logMAR). They report occurrence of posterior capsular tear in vitreous loss in 3% eyes. Thus, with proper ocular surface augmentation, perioperatively, the visual outcomes of cataract surgery are good in patients with DED.
Though it is quite challenging to operate in eyes with severe OSDs, salvaging the visual potential and providing these patients with the best possible visual rehabilitation is also important. The timing of cataract surgery is very crucial to optimize outcomes of cataract surgery and avoid complications in these patients. It is also important to identify and manage the primary pathology leading to the OSD adequately with the required immunosuppressive therapy and surface augmentation procedures. Thus, a stepwise and holistic management of all factors affecting the visual acuity and quality of vision should is required in these patients.
Nil.
There are no conflicts of interest.