Chemical Ocular Injuries
Classification · Pathophysiology · Stepwise Management
Examination question · ~800 words
What are chemical ocular injuries? Discuss their classification (Roper-Hall/Dua), pathophysiology, clinical features, and stepwise management including surgical reconstruction and recent advances.
Try to outline your answer mentally before expanding sections below.
Chemical ocular injuries constitute one of the most time-critical emergencies in ophthalmology. The severity of damage is determined by the nature of the chemical (alkali vs acid), concentration, volume, duration of contact, and the extent of limbal stem cell destruction. Prompt, adequate irrigation is the single most important determinant of outcome. Long-term prognosis depends on the degree of limbal ischaemia and corneal stromal involvement.
Chemical injuries are broadly classified by agent into alkali (base) and acid. The nature of the chemical determines the mechanism of tissue damage, depth of penetration, and overall prognosis.
Alkali vs Acid — Comparative Summary
| Feature | Alkali (Base) | Acid |
|---|---|---|
| Common agents | NaOH (lye), Ca(OH)2 (lime), NH3 (ammonia) | H2SO4, HCl, HF, glacial acetic acid |
| Mechanism | Liquefactive necrosis — saponification of fatty acids, cell membrane disruption | Coagulative necrosis — protein precipitation forms a self-limiting barrier |
| Penetration | Rapid, deep (unbuffered, lipophilic) | Self-limiting (coagulum limits penetration) |
| Anterior chamber | pH rises rapidly; damages trabecular meshwork, lens, ciliary body | Rarely penetrates beyond cornea (except HF) |
| Prognosis | Worse overall | Generally better, except HF |
Exception — Hydrofluoric Acid (HF)
- HF behaves like alkali: penetrates deeply due to small molecular size and high lipid solubility
- Fluoride ions chelate Ca2+ and Mg2+ causing liquefactive necrosis
- Systemic hypocalcaemia is a life-threatening complication — ECG monitoring mandatory
- Treatment: copious irrigation + topical 1% calcium gluconate drops (prepared by diluting 10% calcium gluconate solution with normal saline). NOTE: 2.5% calcium gluconate gel (Calgonate) is labelled for skin use only and must NOT be applied to eyes. Subconjunctival calcium gluconate injection is controversial and may worsen outcomes — avoid. Systemic calcium gluconate IV for documented systemic hypocalcaemia.
Roper-Hall Classification (1965) — Modified from Hughes (1946)/Ballen
The Roper-Hall classification (Trans Ophthalmol Soc UK, 1965) grades burns based on corneal involvement and limbal ischaemia in four grades. Note: some sources attribute it as 'modified Hughes' (Hughes 1946) while others cite 'modified Ballen' — both attributions exist in the literature; 'modified Ballen' appears more frequently in recent peer-reviewed sources.
Roper-Hall Classification
| Grade | Corneal Involvement | Limbal Ischaemia | Prognosis |
|---|---|---|---|
| I | Epithelial erosion only | None | Good |
| II | Hazy; iris details visible | < 1/3 limbus | Good |
| III | Total epithelial loss; iris details obscured | 1/3 – 1/2 limbus | Guarded |
| IV | Opaque; iris/pupil not visible | > 1/2 limbus | Poor |
Dua Classification (2001) — More Granular Limbal Assessment
Dua et al. (Br J Ophthalmol 2001) introduced clock-hour limbal involvement and conjunctival involvement expressed as percentage, yielding 6 grades (I–VI). The descriptive severity labels below are commonly used pedagogical descriptors supplementing the original numerical grading. Grade V and VI (>9 clock hours limbal + >75% conjunctiva) carry the worst prognosis. The Dua system is superior for predicting LSCD outcomes and planning stem cell transplantation.
Dua Classification
| Dua Grade | Limbal Involvement (clock hours) | Conjunctival Involvement | Prognosis |
|---|---|---|---|
| I (Very mild) | 0 | 0% | Excellent |
| II (Mild) | ≤3 | ≤30% | Good |
| III (Moderate) | >3–6 | >30–50% | Good |
| IV (Severe) | >6–9 | >50–75% | Good to guarded |
| V (Very severe) | >9–<12 | >75–<100% | Guarded to poor |
| VI (Total) | 12 (total) | 100% | Very poor |
Roper-Hall uses limbal ischaemia (quadrant estimation); Dua uses precise clock-hour + conjunctival % involvement.
Dua Grade > Roper-Hall Grade IV for planning LSCD surgery (SLET, CLET). Dua Grade V/VI subdivides what was a single Roper-Hall Grade IV — critically important for surgical planning.
Limbal ischaemia = loss of limbal arcade vessels on slit-lamp = whitening/blanching at the limbus.
Roper-Hall Grade I prognosis is 'Good' (not 'Excellent'). Roper-Hall Grade IV is 'Poor' (not 'Very poor' — 'Very poor' belongs to Dua Grade VI).
3.1 Immediate Phase (0–7 days)
- Epithelial cell death → barrier loss → increased corneal permeability
- Alkali saponifies lipid membranes → liquefactive necrosis → unrestricted penetration
- Alkali rapidly raises aqueous humor pH → disrupts ciliary body → reduces aqueous production
- Collagenase (MMP-1, MMP-8, MMP-9) activation from PMNs and keratocytes → stromal melting
- Limbal stem cell (LSC) destruction → failure of corneal epithelial regeneration
- Subconjunctival vessels thrombose → limbal ischaemia → worse LSC damage
3.2 Reparative Phase (1–3 weeks)
- Healing attempted from limbal and conjunctival epithelium
- Persistent epithelial defect if LSCs destroyed → ulceration, melting risk
- Fibrovascular pannus formation (conjunctivalisation of cornea) if LSCD severe
- Symblepharon formation from adherence of raw conjunctival surfaces
- Raised IOP from trabecular damage, peripheral anterior synechiae
3.3 Late Phase (weeks–months)
- Corneal vascularisation, lipid keratopathy
- Cicatricial entropion/ectropion, trichiasis
- Dry eye from goblet cell and lacrimal ductule destruction
- Cataract, phthisis bulbi in severe cases
- Glaucoma from angle damage and steroid use
Copious irrigation must begin IMMEDIATELY — even before formal assessment. Every minute of delay worsens prognosis. The goal is to restore normal ocular pH to 7.0–7.4.
Emergency Step Sequence
| Step | Action | Detail |
|---|---|---|
| 1 | Irrigation — START IMMEDIATELY | Normal saline (preferred), lactated Ringer's, or water. Minimum 2–3 litres over 30 min (alkali: 6+ litres). Irrigate until pH 7.0–7.4. |
| 2 | pH check | Universal pH indicator paper at superior/inferior fornix. Irrigate until pH 7.0–7.4. Recheck 30 minutes after stopping irrigation (to detect alkaline rebound from residual chemical in tissues). |
| 3 | Double evert eyelids | During or after initial irrigation, double-evert eyelids and sweep fornices to remove retained solid particles (especially lime Ca(OH)2, which serves as a reservoir of ongoing chemical injury). |
| 4 | Topical anaesthesia | Proxymetacaine 0.5% — enables compliance with irrigation |
| 5 | Morgan lens / IV cannula | For sustained irrigation in A&E |
| 6 | Document grade | Roper-Hall / Dua grading after irrigation and stabilisation |
Irrigation target pH is 7.0–7.4 (physiologic/neutral). The upper bound of 7.7 overshoots physiologic tear film pH (~7.4) and is not supported in authoritative literature (EyeWiki AAO; PMC7002428).
Universal pH indicator paper (not litmus paper) is required — litmus only gives binary acid/base reading, not a numerical pH value.
pH recheck should be 30 minutes after stopping irrigation, not 5 minutes, to detect alkaline rebound from residual chemical leaching from tissues.
Lime particle removal: AAO consensus is that irrigation should begin IMMEDIATELY. Particle removal occurs during or immediately after the initial irrigation phase — not before irrigation is started.
Acute Medical Management
| Drug | Dose/Route | Mechanism | Duration |
|---|---|---|---|
| Topical steroid (e.g. prednisolone acetate 1%) | Q1–2h initially | Suppress PMN infiltration, reduce collagenase | First 7–10 days only (taper rapidly); risk of melting if prolonged |
| Topical antibiotic (e.g. chloramphenicol, moxifloxacin) | QID | Prevent secondary infection of epithelial defect | Until epithelium healed |
| Topical ascorbate (Vit C 10%) | Q2h | Substrate for collagen synthesis; reduces PMN oxidant damage | 4–6 weeks |
| Systemic ascorbic acid (oral) | 2 g QID (8 g/day total); dose-reduce in renal impairment | Systemic replenishment; reduces stromal melting (Pfister rabbit models) | 4–6 weeks |
| Systemic tetracycline (doxycycline 100 mg BD) | Oral | MMP inhibitor — reduces collagenase-mediated ulceration | 4–6 weeks |
| Topical citrate (10% sodium citrate) | Q2h | Chelates calcium → reduces PMN chemotaxis, oxidant burst | 4–6 weeks |
| Topical cyclopentolate or atropine | BD–TID | Prevent synechiae, reduce ciliary spasm, improve comfort | Until quiet |
| IOP-lowering agents (e.g. timolol, brimonidine) | BD | Raised IOP common from trabecular damage | As required |
| Preservative-free lubricants | Hourly | Maintain ocular surface; reduce desiccation | Long-term |
Systemic ascorbic acid dose: 2 g QID (8 g/day total in adults with normal renal function). The lower dose of 1–2 g/day cited in some older texts is 4–8 times below the standard clinical dose and provides inadequate anti-collagenase and collagen-synthesis support (EyeWiki AAO; Medscape Chemical Burns Treatment).
Use steroids aggressively in week 1. TAPER RAPIDLY after day 7–10: in the reparative phase, steroids inhibit keratocyte collagen synthesis, shifting the balance toward MMP-mediated degradation — risk of stromal melt/perforation. After week 3, avoid topical steroids unless epithelium is intact and re-inflammation is documented.
Avoid prostaglandin analogues for IOP elevation in acute phase (disrupted blood-aqueous barrier).
5.1 Amniotic Membrane Transplantation (AMT)
- Indication: moderate-to-severe injuries (Grade II–IV Roper-Hall, depending on clinical response); within 2 weeks of injury in the acute phase
- Acts as biological bandage: anti-inflammatory, anti-scarring, promotes epithelialisation
- Multilayer sutured AMT for severe cases with stromal loss; single-layer AMT or Prokera device for moderate cases. NOTE: Prokera is a single-layer cryopreserved amniotic membrane device (mounted on a polycarbonate ring) — NOT a multilayer AMT. Multilayer AMT is a distinct surgical technique involving sutured multiple layers of AM.
- Reduces symblepharon, limbal inflammation, stromal melt
- Landmark: Meller et al. (Ophthalmology 2000) — AMT in acute chemical burns markedly reduced scarring and LSCD
5.2 Limbal Stem Cell Transplantation — For LSCD
LSCT Procedures
| Procedure | Source | Indication | Note |
|---|---|---|---|
| CLAU (Conjunctival-Limbal Autograft) | Fellow eye (autologous) | Unilateral severe chemical injury | No systemic immunosuppression required; carries risk to donor eye |
| CLET (Cultured Limbal Epithelial Transplant) | Small biopsy, cultured on AM/fibrin substrate | When donor limbus is limited | Avoids large donor harvest |
| SLET (Simple Limbal Epithelial Transplant) | Small autologous biopsy, transplanted directly on AM | Unilateral LSCD | Simple, low-cost; pioneered by Sangwan et al. (Br J Ophthalmol 2012) |
| KLAL (Keratolimbal Allograft) | Cadaveric / living related donor | Bilateral severe LSCD | Requires systemic immunosuppression lifelong |
| COMET (Cultivated Oral Mucosal Epithelial Transplant) | Autologous oral mucosa | No suitable limbal tissue (bilateral disease) | Reduces conjunctivalisation; provides alternative mucosal epithelial surface — outcomes variable |
5.3 Keratoprosthesis (KPro)
- Boston KPro Type II: indicated for end-stage bilateral chemical burns with severe dry eye/keratinisation where conventional PKP/DALK would fail
- Type II has an anterior-posterior stem traversing the permanently closed lid (permanent tarsorrhaphy required)
- High risk of retroprosthetic membrane, glaucoma, endophthalmitis — requires lifelong topical antibiotics
- Osteo-odonto-keratoprosthesis (OOKP): Uses patient's own tooth/bone lamina to support optical cylinder — gold standard for end-stage bilateral chemical burns in select centres
5.4 Other Reconstructive Procedures
- Symblepharon lysis + mucous membrane grafting (hard palate, buccal mucosa)
- Penetrating Keratoplasty (PKP) / DALK: Only after ocular surface is fully stable (LSCD corrected); failure rate near-universal without prior LSC transplant
- Glaucoma drainage devices (Ahmed, Baerveldt): For refractory post-chemical IOP elevation
- Lid reconstruction: Cicatricial entropion correction, punctal occlusion for severe dry eye
Complications by System
| System | Complication | Management Principle |
|---|---|---|
| Cornea | Persistent epithelial defect, stromal ulcer, perforation | AMT, bandage CL, cyanoacrylate glue, tectonic graft |
| Cornea | Corneal opacification, vascularisation | LSCT then PKP/DALK after stable surface |
| Limbus | LSCD → conjunctivalisation | SLET/CLET/KLAL depending on laterality |
| Conjunctiva | Symblepharon, fornix shortening | Mucous membrane grafting, ring conformers |
| Lids | Cicatricial entropion/ectropion, trichiasis | Tarsal fracture, mucous membrane graft |
| IOP | Glaucoma (acute/chronic) | Medical, trabeculectomy, GDD |
| Lens | Cataract (alkali penetration) | Phacoemulsification after surface stabilised |
| Dry eye | Goblet cell / lacrimal ductule destruction | Autologous serum, punctal occlusion, scleral lens |
| Anterior segment | Phthisis bulbi (end-stage) | Evisceration / cosmetic prosthesis |
- Cultivated Oral Mucosal Epithelial Transplant (COMET): Avoids need for limbal tissue; useful when both eyes affected. Nishida et al. (NEJM 2004) and Inatomi et al. (AJO 2006) have shown promising results.
- Ex vivo expanded limbal epithelial stem cells on fibrin/AM substrate (CLET): Rama et al. showed long-term restoration in 76.6% of patients (N Engl J Med 2010 — NEJM 2010;363(2):147–155). Note: Rama P is first author; Pellegrini G is senior author.
- Induced pluripotent stem cells (iPSC) → corneal epithelium: Investigational; future promise for bilateral LSCD.
- Anti-VEGF therapy: Subconjunctival bevacizumab (monoclonal antibody/biologic agent) reduces corneal neovascularisation and pannus — distinct from gene therapy.
- Gene therapy: Experimental viral vector delivery of anti-angiogenic genes (e.g., sFlt-1) to reduce post-chemical corneal neovascularisation — ongoing preclinical/early clinical research.
- Boston KPro Type II modifications: Improved haptic design to reduce sterile keratolysis.
- Corneal neurotisation: For neurotrophic keratopathy post-chemical injury — coaptation of supratrochlear nerve.
Chemical ocular injuries demand a tiered, time-sensitive approach. Irrigation within seconds is the single most impactful intervention. Grading (Dua/Roper-Hall) drives prognosis and reconstructive planning. Medical management suppresses the destructive inflammatory cascade, while surgical management addresses LSCD, symblepharon, corneal opacity, and raised IOP in a staged, logical sequence. The goal is progressive ocular surface rehabilitation — from emergency irrigation to eventual visual restoration.
Trap 1 — FALSE
“Roper-Hall Grade I prognosis is 'Excellent'”
Roper-Hall Grade I prognosis is 'Good', not 'Excellent'. Most authoritative sources (StatPearls NBK459221, PMC4106115, EyeRounds Iowa) consistently list Grade I as 'Good'.
Trap 2 — FALSE
“Roper-Hall Grade IV prognosis is 'Very poor'”
Roper-Hall Grade IV prognosis is 'Poor', not 'Very poor'. 'Very poor' belongs to Dua Grade VI (12 clock hours + 100% conjunctiva). Conflating the two systems is a common error — Dua Grade VI subdivides what was Roper-Hall Grade IV.
Trap 3 — FALSE
“Prokera rings are used for multilayer AMT in severe cases”
Prokera is a single-layer, self-retaining cryopreserved amniotic membrane device mounted on a polycarbonate ring — it is NOT a multilayer AMT. Multilayer (sutured) AMT is a distinct surgical technique for severe cases with stromal loss. Prokera is used for moderate cases.
Trap 4 — FALSE
“SLET was pioneered by Amescua et al.”
SLET (Simple Limbal Epithelial Transplantation) was pioneered by Sangwan VS et al. (Br J Ophthalmol 2012;96(7):931–934). Amescua et al. published a modification using cryopreserved AM (AJO 2014) but are not the originators of the procedure.
Trap 5 — FALSE
“Pellegrini et al. showed 78% long-term corneal restoration in the NEJM 2010 CLET landmark”
Three errors: (1) First author is Rama P, not Pellegrini (Pellegrini G is the senior author); (2) Success rate was 76.6%, not 78%; (3) The correct citation is: Rama P, Matuska S, Paganoni G, et al. N Engl J Med. 2010;363(2):147–155.
Trap 6 — FALSE
“Bevacizumab is a form of gene therapy for corneal neovascularisation”
Bevacizumab is a monoclonal antibody (biologic agent), NOT gene therapy. Gene therapy involves delivering genetic material via viral vectors (e.g., sFlt-1, endostatin gene transfer). Subconjunctival bevacizumab is anti-VEGF therapy, a distinct modality from experimental gene therapy.
Trap 7 — FALSE
“Litmus paper accurately measures tear pH after irrigation”
Litmus paper only provides a binary acid/base indication — it cannot give a numerical pH reading. Universal pH indicator strips (or a pH meter) are required for accurate pH assessment at the fornix.
Trap 8 — FALSE
“Irrigation target pH is 7.3–7.7”
The target endpoint is pH 7.0–7.4 (physiologic/neutral). An upper bound of 7.7 overshoots physiologic tear film pH (~7.4) and is not supported in authoritative literature (EyeWiki AAO; PMC7002428).
Trap 9 — FALSE
“2.5% calcium gluconate gel (Calgonate) can be applied to the eye in HF burns”
Calgonate 2.5% gel is explicitly labelled for skin use only. It must NOT be applied to eyes (CDC/NIOSH; manufacturer labelling). For ocular HF burns, use 1% calcium gluconate eye drops (prepared by diluting 10% calcium gluconate with normal saline).
Trap 10 — FALSE
“Steroids should be continued throughout the reparative phase to suppress inflammation”
Steroids must be tapered rapidly after day 7–10. In the reparative phase, steroids inhibit keratocyte collagen synthesis — shifting the balance toward MMP-mediated degradation and increasing the risk of stromal melt and corneal perforation. Anti-MMP agents (tetracyclines, sodium citrate, ascorbic acid) are preferred beyond this phase.
Q: Why is alkali worse than acid in ocular chemical injuries?
A: Alkali causes liquefactive necrosis with saponification of fatty acids in cell membranes — there is no coagulum barrier (unlike acid). This allows unrestricted penetration into the anterior chamber, damaging the trabecular meshwork, lens, ciliary body, and even the retina in severe cases. The aqueous pH can rise rapidly (especially with NH3). Acid coagulative necrosis is self-limiting — except hydrofluoric acid, which penetrates like an alkali due to small molecular size and lipid solubility.
Q: What is the clinical significance of limbal blanching in chemical injuries?
A: Limbal blanching = thrombosis/ischaemia of episcleral vessels at the limbus = destruction of the limbal stem cell niche (palisades of Vogt). Loss of LSCs leads to LSCD → conjunctivalisation of the cornea → loss of transparency, vascularisation, and recurrent erosions. Grading limbal ischaemia (Roper-Hall/Dua) directly predicts prognosis and guides surgical planning for stem cell transplantation.
Q: Why should topical steroids be tapered after 10 days in chemical injury?
A: In the reparative phase (weeks 2–3), stromal keratocytes are actively proliferating and depositing collagen. Steroids inhibit keratocyte collagen synthesis, shifting the balance toward MMP-mediated degradation — increasing the risk of stromal melt and corneal perforation. Anti-MMP agents (tetracyclines, sodium citrate, ascorbic acid) are preferred beyond this phase.
Q: Which alkali penetrates the eye most rapidly, and why?
A: Ammonia (NH3) — smallest molecular weight alkali — rapidly penetrates the cornea and elevates anterior chamber pH within seconds. Not NaOH (though highly caustic): NH3's combination of small molecular size and lipid solubility gives it the fastest anterior chamber penetration of all alkalis.
Q: When is PKP contraindicated after chemical burns?
A: PKP should NOT be performed until: (a) LSCD is corrected with limbal stem cell transplantation, (b) ocular surface is fully stable with no active inflammation, (c) dry eye is adequately managed. Performing PKP on a stem-cell-deficient, inflamed eye leads to near-universal graft failure from recurrent conjunctivalisation.
Q: Explain the dual role of vitamin C (ascorbic acid) in chemical injury management.
A: Ascorbate serves two roles: (1) Substrate for collagen hydroxylation — chemical injury depletes ascorbate in the aqueous and cornea, impairing collagen synthesis and stromal repair; (2) Antioxidant — reduces PMN-derived reactive oxygen species that cause stromal melting. Topical 10% Q2h and systemic 2 g QID (8 g/day) are standard (Pfister & Paterson rabbit models; EyeWiki AAO).
A 28-year-old construction worker presents 6 hours after bilateral lime splash. Vision: perception of light bilaterally. Dua Grade V bilaterally. IOP 48 mmHg right, 42 mmHg left. Outline your surgical strategy over the next 12 months.
Immediate (Day 0–2)
IV mannitol + topical IOP lowering; avoid prostaglandin analogues (disrupted blood-aqueous barrier). Continue irrigation until pH 7.0–7.4 with universal pH indicator strips. Commence systemic ascorbic acid 2 g QID, doxycycline 100 mg BD, topical cycloplegic, topical ascorbate 10% Q2h, sodium citrate 10% Q2h, preservative-free lubricants hourly.
Week 1–2
Bilateral multilayer sutured amniotic membrane transplantation to suppress acute inflammation and reduce LSCD extension. Ring conformers to prevent symblepharon formation. Taper topical steroids after day 7–10 to avoid stromal melt in the reparative phase.
Month 2–3
After stabilisation, plan bilateral limbal stem cell transplantation. As bilateral LSCD: options are (1) KLAL from cadaveric donor (requires systemic immunosuppression — MMF + tacrolimus + low-dose prednisolone) or (2) bilateral CLET from small cultivated biopsy (smaller donor harvest, suitable for bilateral disease) or (3) COMET if no usable limbal tissue.
Month 6+
Once ocular surface re-epithelialised and stable, consider PKP/DALK for visual rehabilitation if corneal opacification persists. Only proceed after LSCD is corrected, surface is quiet, and dry eye is managed — premature PKP carries near-universal graft failure risk.
Long-term and Fallback
Glaucoma drainage device (Ahmed valve) if IOP remains uncontrolled medically. Boston KPro Type II or OOKP reserved for failure of all above in a keratinised, dry, closed-lid environment. Psychosocial: Low vision aids, occupational counselling, medicolegal documentation for workplace compensation.
References
- Kanski JJ, Bowling B. Clinical Ophthalmology: A Systematic Approach. 8th ed. Elsevier; 2016.
- Yanoff M, Duker JS. Ophthalmology. 6th ed. Elsevier; 2022.
- Roper-Hall MJ. Thermal and chemical burns. Trans Ophthalmol Soc UK. 1965;85:631–653.
- Dua HS, King AJ, Joseph A. A new classification of ocular surface burns. Br J Ophthalmol. 2001;85(11):1379–1383.
- Pfister RR, Paterson CA. Ascorbic acid in the treatment of alkali burns of the eye. Ophthalmology. 1980;87:1050–1057.
- Meller D, Pires RTF, Mack RJS, et al. Amniotic membrane transplantation for acute chemical or thermal burns. Ophthalmology. 2000;107(5):980–989.
- Pellegrini G, Rama P, Mavilio F, De Luca M. Epithelial stem cells in corneal regeneration and epidermal gene therapy. J Pathol. 2009;217(2):217–228.
- Rama P, Matuska S, Paganoni G, Spinelli A, De Luca M, Pellegrini G. Limbal stem-cell therapy and long-term corneal regeneration. N Engl J Med. 2010;363(2):147–155.
- Inatomi T, Nakamura T, Koizumi N, et al. Midterm results on ocular surface reconstruction using cultivated autologous oral mucosal epithelial transplantation. Am J Ophthalmol. 2006;141(2):267–275.
- Sangwan VS, Basu S, MacNeil S, Balasubramanian D. Simple limbal epithelial transplantation (SLET): a novel surgical technique for the treatment of unilateral limbal stem cell deficiency. Br J Ophthalmol. 2012;96(7):931–934.
- Amescua G, Atallah M, Nikpoor N, Galor A, Perez VL. Modified simple limbal epithelial transplantation using cryopreserved amniotic membrane for unilateral limbal stem cell deficiency. Am J Ophthalmol. 2014;158(3):469–475.
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- Sharma N, Kaur M, Agarwal T, Sangwan VS, Vajpayee RB. Treatment of acute ocular chemical burns. Surv Ophthalmol. 2018;63(2):214–235.
- Wagoner MD. Chemical injuries of the eye: current concepts in pathophysiology and therapy. Surv Ophthalmol. 1997;41(4):275–313.